阅读说明：本技术 旋转电机的驱动装置 (Drive device for rotating electric machine ) 是由 金城博文 谷口真 于 2019-02-05 设计创作，主要内容包括：旋转电机的驱动装置包括：第一逆变器(40),该第一逆变器通过使针对第一绕组(33a)的各相的上下臂开关(41、42)开闭来进行第一绕组的通电；第二逆变器(50),该第二逆变器通过使针对第二绕组(33b)的各相的上下臂开关(51、52)开闭来进行第二绕组的通电；设于电流路径(47)的第一切换开关(48)；设于电流路径(57)的第二切换开关(58)；第一通电控制部(65),该第一通电控制部在使第一切换开关和第二切换开关打开的状态下,使第一逆变器和第二逆变器中的上下臂的各开关以相同的通电期间分别互补地开闭,从而控制第一绕组和第二绕组的通电；以及第二通电控制部(65),该第二通电控制部在使第一切换开关和第二切换开关闭合的状态下,使第一逆变器的上臂开关和第二逆变器的下臂开关交替地开闭,从而控制第一绕组和第二绕组的通电。(A drive device for a rotating electric machine includes: a first inverter (40) that energizes the first winding (33a) by opening and closing upper and lower arm switches (41, 42) for each phase of the first winding; a second inverter (50) that energizes the second winding (33b) by opening and closing upper and lower arm switches (51, 52) for each phase of the second winding; a first changeover switch (48) provided in the current path (47); a second selector switch (58) provided in the current path (57); a first energization control unit (65) that controls energization of the first winding and the second winding by opening and closing the switches of the upper and lower arms in the first inverter and the second inverter in a complementary manner for the same energization period in a state where the first changeover switch and the second changeover switch are opened; and a second energization control unit (65) that controls energization of the first winding and the second winding by alternately opening and closing an upper arm switch of the first inverter and a lower arm switch of the second inverter in a state where the first changeover switch and the second changeover switch are closed.)

1. A drive device for a rotating electric machine is provided,

is applied to and drives a rotating electrical machine (10) having: a stator core (31); a first winding (33a) and a second winding (33b) that are wound around the stator core, each of the first and second windings being formed of at least three-phase winding portions, and each of the phases having one end of the winding portion connected to a neutral point (N1, N2), the drive device for a rotating electrical machine comprising:

a first inverter (40) connected to a direct-current power supply (60) and configured to perform energization of each phase of the first winding by opening and closing an upper arm switch (41) and a lower arm switch (42) provided for each phase of the first winding;

a second inverter (50) connected to the DC power supply, and configured to perform energization of each phase of the second winding by opening and closing an upper arm switch (51) and a lower arm switch (52) provided for each phase of the second winding;

a first changeover switch (48) provided in a current path (47) connecting a neutral point of the first winding and a low potential side of the direct current power supply;

a second selector switch (58) provided on a current path (57) connecting a neutral point of the second winding and a high potential side of the DC power supply;

a first energization control unit (65) that controls energization of the first winding and the second winding by opening and closing the switches of the upper and lower arms of the first inverter and the second inverter in a complementary manner in the same energization period in a state where the first changeover switch and the second changeover switch are opened; and

and a second energization control unit (65) that controls energization of the first winding and the second winding by alternately opening and closing the upper arm switch among the switches of the upper and lower arms of the first inverter and the lower arm switch among the switches of the upper and lower arms of the second inverter for a predetermined energization period in a state where the first changeover switch and the second changeover switch are closed.

2. The drive apparatus of a rotating electric machine according to claim 1,

in an operation region on a low rotation side of the rotating electrical machine, the first energization control unit performs energization control of the windings in a state where the first changeover switch and the second changeover switch are opened,

in an operation region on a high rotation side of the rotating electrical machine, the second energization control unit performs energization control of the windings in a state where the first changeover switch and the second changeover switch are closed.

3. The drive device of a rotating electric machine according to claim 1 or 2,

the upper arm switch and the lower arm switch of the first inverter and the upper arm switch and the lower arm switch of the second inverter are semiconductor switching elements (41, 42, 51, 52) having free wheeling diodes (43, 44, 53, 54) connected in a direction to be antiparallel,

the first inverter has a first cut-off unit (45, 42a, 42b) that cuts off a return path (R1) that includes the return diode and the first winding of the lower arm switch of the first inverter when the second conduction control unit switches from a state in which the upper arm switch of the first inverter is opened and closed to a state in which the lower arm switch of the second inverter is opened and closed,

the second inverter has a second cut-off unit (55, 51a, 51b) that cuts off a return path (R2) that includes the return diode and the second winding of the upper arm switch of the second inverter when the second conduction control unit switches from a state in which the lower arm switch of the second inverter is opened and closed to a state in which the upper arm switch of the first inverter is opened and closed.

4. The drive apparatus of a rotating electric machine according to claim 3,

an AC line connecting the intermediate point of each switch of the upper and lower arms of the first inverter and the winding part of each phase of the first winding is provided with a first additional switch (45) as the first cut-off part for opening and closing the AC line,

a second additional switch (55) for opening and closing an alternating current line connecting an intermediate point of each switch of the upper and lower arms of the second inverter and the winding part of each phase of the second winding is provided as the second cut-off part,

the first energization control unit turns on the first changeover switch and the second changeover switch and turns off the first additional switch and the second additional switch,

the second energization control unit turns off the first additional switch and turns on the second additional switch during an energization period for turning on and off the upper arm switch of the first inverter in a state where the first changeover switch and the second changeover switch are closed, and turns on the first additional switch and turns off the second additional switch during an energization period for turning on and off the lower arm switch of the second inverter.

5. The drive apparatus of a rotating electric machine according to claim 3,

the first inverter has a pair of semiconductor switching elements (42a, 42b) as the lower arm switches of the respective phases, the pair of semiconductor switching elements being connected in series with each other and having return diodes (44a, 44b) arranged in reverse directions to each other,

the second inverter has a pair of semiconductor switching elements (51a, 51b) as the upper arm switches of the respective phases, the pair of semiconductor switching elements being connected in series with each other and having reflux diodes (53a, 53b) arranged in reverse directions to each other,

the first cut-off unit is configured by a pair of the semiconductor switching elements of the first inverter, and the second cut-off unit is configured by a pair of the semiconductor switching elements of the second inverter.

6. The drive apparatus of a rotating electric machine according to claim 5,

the first energization control unit controls energization of the first winding and the second winding such that one semiconductor switching element of a pair of the semiconductor switching elements of the first inverter is complementarily opened and closed with respect to the upper arm switch of the first inverter and the other semiconductor switching element is kept in a closed state,

one of the pair of semiconductor switching elements of the second inverter is complementarily opened and closed with respect to the lower arm switch of the second inverter, and the other semiconductor switching element is held in a closed state.

7. The drive device of a rotating electric machine according to claim 1 or 2,

the first inverter has a semiconductor switching element (41) as the upper arm switch of the first inverter and a pair of IGBTs (42c, 42d) as the lower arm switch, the semiconductor switching element having a reflux diode (43) connected in a direction to become anti-parallel, the pair of IGBTs being connected in anti-parallel with each other,

the second inverter has a semiconductor switching element (52) as the lower arm switch of the second inverter and a pair of IGBTs (51c, 51d) as the upper arm switch, the semiconductor switching element having a reflux diode (54) connected in a direction to become antiparallel, the pair of IGBTs being connected in antiparallel with each other,

a second switching control unit configured to switch the upper arm switch of the first inverter from a state of opening and closing the upper arm switch to a state of opening and closing the lower arm switch of the second inverter, wherein a return path, which is a path including the lower arm switch of the first inverter and the first winding, is cut off by a pair of IGBTs provided as the lower arm switch,

when the second energization control unit switches from a state in which the lower arm switch of the second inverter is opened and closed to a state in which the upper arm switch of the first inverter is opened and closed, a return path, which is a path including the upper arm switch of the second inverter and the second winding, is cut off by a pair of IGBTs provided as the upper arm switch.

8. The drive apparatus of a rotating electric machine according to claim 7,

the first energization control unit controls the first winding and the second winding to be energized, wherein the first energization control unit causes one of the IGBTs of the pair of IGBTs of the first inverter to open and close complementarily with respect to the upper arm switch of the first inverter, and causes the other IGBT to be kept in a closed state,

one of the pair of IGBTs of the second inverter is complementarily opened and closed with respect to the lower arm switch of the second inverter, and the other IGBT is kept in a closed state.

9. The drive device of a rotating electric machine according to any one of claims 1 to 8,

the first winding and the second winding have the same number of turns, and the conductors in the same phase are accommodated in the same slot (32) of the stator core.

10. The drive apparatus of a rotating electric machine according to claim 9,

the first winding and the second winding are formed of conductors having a rectangular cross section.

Technical Field

The present invention relates to a drive device for a rotating electric machine.

Background

Conventionally, in a drive device for a rotating electrical machine, a technique has been proposed in which a control mode of the rotating electrical machine is appropriately switched between two rotation modes, i.e., high-speed rotation and low-speed rotation. For example, according to the technique described in patent document 1, a series connection body including an upper arm switch and a lower arm switch is provided for each phase of a Y-connected three-phase winding, and a speed change switch is connected to a neutral point of the three-phase winding. In addition, the speed switch is turned off in the low-speed rotation mode to perform full-wave driving, and the speed switch is turned on in the high-speed rotation mode to perform half-wave driving, thereby obtaining two torque characteristics.

Disclosure of Invention

However, according to the technique described in patent document 1, the full-wave drive and the half-wave drive can be switched by turning on and off the speed switch, but there is a concern that torque ripple may become large when the half-wave drive is performed by turning on the speed switch.

The present invention has been made in view of the above-described problems, and a main object of the present invention is to provide a driving device for a rotating electrical machine, which can perform full-wave driving and half-wave driving in an ideal manner, and which can reduce torque ripple during half-wave driving.

The following describes a solution to the above-described problems and its operational effects.

According to a first aspect of the present invention,

a drive device for a rotating electrical machine, which is applied to and drives the rotating electrical machine, includes: a stator core; a first winding and a second winding wound around the stator core, each of the first and second windings being formed of at least three-phase winding portions, and one end of each of the winding portions of each phase being connected to each other through a neutral point, the drive device including:

a first inverter connected to a direct current power supply (60) and configured to perform energization of each phase of the first winding by opening and closing an upper arm switch and a lower arm switch provided for each phase of the first winding;

a second inverter connected to the dc power supply, the second inverter performing energization of each phase of the second winding by opening and closing an upper arm switch and a lower arm switch provided for each phase of the second winding;

a first changeover switch provided in a current path connecting a neutral point of the first winding and a low potential side of the direct current power supply;

a second changeover switch provided in a current path connecting a neutral point of the second winding and a high potential side of the dc power supply;

a first energization control unit that controls energization of the first winding and the second winding by opening and closing the switches of the upper and lower arms of the first inverter and the second inverter in a complementary manner for the same energization period in a state where the first changeover switch and the second changeover switch are opened; and

and a second energization control unit that controls energization of the first winding and the second winding by alternately opening and closing the upper arm switch among the switches of the upper and lower arms of the first inverter and the lower arm switch among the switches of the upper and lower arms of the second inverter for a predetermined energization period in a state where the first changeover switch and the second changeover switch are closed.

The rotating electric machine has a first winding and a second winding of at least three phases, and energization of the windings is controlled by a first inverter and a second inverter, respectively. In particular, a first change-over switch is provided on a path connecting the neutral point of the first winding and the low potential side of the dc power supply, and a second change-over switch is provided on a path connecting the neutral point of the second winding and the high potential side of the dc power supply, whereby the on/off states of the change-over switches are appropriately changed. According to the above configuration, the full-wave drive mode and the half-wave drive mode can be switched as the drive mode of the rotating electrical machine by switching each of the changeover switches to the on state and the off state.

That is, in a state where the first changeover switch and the second changeover switch are opened, the switches of the upper and lower arms of the first inverter and the second inverter are complementarily opened and closed, respectively, for the same energization period, thereby controlling the energization of the first winding and the second winding. That is, the inverters perform full-wave driving of the rotating electric machine. In this case, the same energization period is controlled for the same energization period in the first winding and the second winding, and high torque can be output.

In addition, in a state where the first changeover switch and the second changeover switch are closed, an upper arm switch among the respective switches of the upper and lower arms of the first inverter and a lower arm switch among the respective switches of the upper and lower arms of the second inverter are alternately opened and closed for a certain energization period, respectively, thereby controlling energization of the first winding and the second winding. That is, the half-wave drive of the rotating electric machine is performed alternately in each inverter. In this case, the first winding and the second winding are wound around the stator core and magnetically coupled to each other, and on the other hand, on the first winding side, the neutral point and the low potential side of the dc power supply are short-circuited by the first changeover switch, and on the second winding side, the neutral point and the high potential side of the dc power supply are short-circuited by the second changeover switch. Therefore, during the energization of the first winding and during the energization of the second winding, the directions of the phase currents are respectively opposite to each other and change positively and negatively. Further, by setting the energization period of the first winding and the energization period of the second winding to be different from each other, a synthetic magnetomotive force of a full wave shape can be obtained. That is, although half-wave driving is performed, a sinusoidal rotating magnetic field similar to that in full-wave driving can be obtained. In summary, it is possible to desirably perform full-wave driving and half-wave driving, and reduce torque ripple at the time of half-wave driving.

According to the second aspect, the first energization control unit opens the first changeover switch and the second changeover switch to control energization of the windings in an operating region on a low rotation side of the rotating electrical machine, and the second energization control unit closes the first changeover switch and the second changeover switch to control energization of the windings in an operating region on a high rotation side of the rotating electrical machine.

According to the above configuration, since the respective change-over switches are opened and closed in accordance with the operation region of the rotating electric machine, different output characteristics can be obtained desirably, and the high-efficiency operation region of the rotating electric machine can be enlarged. Further, as described above, according to the configuration in which the neutral point of the first winding and the low potential side of the dc power supply are short-circuited by the first changeover switch, and the neutral point of the second winding and the high potential side of the dc power supply are short-circuited by the second changeover switch, the applied voltage per unit winding of the winding unit of each phase can be made higher than that in the full-wave driving in the state in which each changeover switch is closed. Therefore, an advantageous configuration can be realized in addition to expanding the operation region of the rotating electric machine toward the high rotation region side.

According to a third aspect, the upper arm switch and the lower arm switch of the first inverter and the upper arm switch and the lower arm switch of the second inverter are semiconductor switching elements having a reflux diode connected in a direction of being antiparallel to each other, the first inverter has a first cutoff portion that cuts off a reflux path including the reflux diode and the first winding of the lower arm switch of the first inverter when the second energization control portion switches from a state of opening and closing the upper arm switch of the first inverter to a state of opening and closing the lower arm switch of the second inverter, the second inverter has a second cutoff portion that opens and closes the upper arm switch of the first inverter from a state of opening and closing the lower arm switch of the second inverter, the second cutoff unit cuts off a return path including the return diode of the upper arm switch of the second inverter and the second winding.

In the half-wave drive, when the upper arm switch of the first inverter is switched from the on/off state to the on/off state, the first winding and the second winding are magnetically coupled to each other, and therefore, the current is transferred from the first winding to the second winding. However, when the switching is performed, if a return path is formed on the first inverter side, there is a possibility that the switching cannot be performed appropriately. That is, in the first inverter, since the upper arm switch and the lower arm switch are provided with the free wheeling diodes, a free wheeling path is formed in the first inverter via the free wheeling diodes and the windings. Conversely, the same applies to switching from the state in which the lower arm switch of the second inverter is opened and closed to the state in which the upper arm switch of the first inverter is opened and closed.

In this regard, according to the above aspect, in the first inverter, when the second energization controlling unit switches from the state in which the upper arm switch of the first inverter is opened and closed to the state in which the lower arm switch of the second inverter is opened and closed, the first cutting unit cuts the return path, which is the path including the return diode and the first winding of the lower arm switch of the first inverter. In the second inverter, when the second energization control unit switches from a state in which the lower arm switch of the second inverter is opened and closed to a state in which the upper arm switch of the first inverter is opened and closed, the second cutoff unit cuts off a return path that includes a path between the return diode and the second winding of the upper arm switch of the second inverter. This makes it possible to desirably perform commutation between the first winding side and the second winding side, and to appropriately perform complementary half-wave drive in each winding.

According to a fourth aspect, the first cut-off unit includes a first additional switch for opening and closing an ac line connecting an intermediate point of each switch of the upper and lower arms of the first inverter and the winding unit of each phase of the first winding, the second cut-off unit includes a second additional switch for opening and closing the ac line connecting an intermediate point of each switch of the upper and lower arms of the second inverter and the winding unit of each phase of the second winding, the first energization control unit opens the first and second change-over switches and closes the first and second additional switches, and the second energization control unit closes the first and second change-over switches during energization for opening and closing the upper arm switch of the first inverter, the first additional switch is turned off and the second additional switch is turned on, and the first additional switch is turned on and the second additional switch is turned off during the conduction period for turning on and off the lower arm switch of the second inverter.

According to the above aspect, since the first additional switch is provided as the first cutoff portion on the ac line connecting the intermediate point of the upper and lower arms of the first inverter and the winding portion of each phase, when the lower arm switch of the second inverter is opened and closed by the second energization controlling portion, the return path formed by the lower arm switch including the first inverter can be desirably cut by the first additional switch.

Further, since the second additional switch is provided as the second cutoff portion on the ac line connecting the intermediate point of the upper and lower arms of the second inverter and the winding portion of each phase, when the upper arm switch of the first inverter is opened and closed by the second energization controlling portion, the return path formed by the upper arm switch including the second inverter can be desirably cut by the second additional switch. Thus, complementary half-wave drive in the winding that becomes the power-on side can still be appropriately performed.

According to a fifth aspect, the first inverter has a pair of semiconductor switching elements as the lower arm switch of each phase, the pair of semiconductor switching elements are connected in series with each other and have reflux diodes provided in opposite directions from each other, the second inverter has a pair of semiconductor switching elements as the upper arm switch of each phase, the pair of semiconductor switching elements are connected in series with each other and have reflux diodes provided in opposite directions from each other, the first cut-off portion is constituted by the pair of semiconductor switching elements of the first inverter, and the second cut-off portion is constituted by the pair of semiconductor switching elements of the second inverter.

According to the above aspect, a pair of semiconductor switching elements (i.e., anti-series semiconductor switching elements) serving as the lower arm switches of the respective phases of the first inverter are provided, the pair of semiconductor switching elements being connected in series with each other and having the return diodes provided in opposite directions to each other, the pair of semiconductor switching elements being the first cut-off portion, and the pair of semiconductor switching elements functioning as the bidirectional switches capable of bidirectional energization and bidirectional cutting-off. This makes it possible to desirably cut off the return path formed by the lower arm switch including the first inverter.

In the second inverter as well, a pair of semiconductor switching elements (i.e., anti-series semiconductor switching elements) serving as upper arm switches of the respective phases are provided, the pair of semiconductor switching elements being connected in series with each other and having reflux diodes provided in opposite directions to each other, the pair of semiconductor switching elements serving as second cut-off sections, and the pair of semiconductor switching elements functioning as bidirectional switches capable of bidirectional energization and bidirectional cut-off. This makes it possible to desirably cut off the return path formed by the upper arm switch including the second inverter.

According to a sixth aspect, when controlling the current supply to the first winding and the second winding, the first current supply control unit performs: one of the pair of semiconductor switching elements of the first inverter is complementarily opened and closed with respect to the upper arm switch of the first inverter and the other semiconductor switching element is kept in a closed state, and one of the pair of semiconductor switching elements of the second inverter is complementarily opened and closed with respect to the lower arm switch of the second inverter and the other semiconductor switching element is kept in a closed state.

According to the above aspect, in the configuration having the pair of semiconductor switching elements connected in anti-series as the lower arm switch of the first inverter and the pair of semiconductor switching elements connected in anti-series as the upper arm switch of the second inverter, during full-wave driving, one of the pair of semiconductor switching elements of each inverter is opened and closed, and the other is kept in the closed state, thereby controlling the current to be supplied. In this case, the full-wave drive can be appropriately performed by performing the reflux operation or the regeneration operation when the power factor is not 1.

According to a seventh aspect, the first inverter has a semiconductor switching element as the upper arm switch of the first inverter and a pair of IGBTs as the lower arm switch, the semiconductor switching element has a reflux diode connected in a direction to become antiparallel, the pair of IGBTs are connected in reverse parallel to each other, the second inverter has a semiconductor switching element as the lower arm switch of the second inverter and a pair of IGBTs as the upper arm switch, the semiconductor switching element has a reflux diode connected in a direction to become antiparallel, the pair of IGBTs are connected in reverse parallel to each other, and when switching is made by the second energization control portion from a state in which the upper arm switch of the first inverter is turned on and off to a state in which the lower arm switch of the second inverter is turned on and off, the lower arm switch including the first inverter and the first IGBT are turned on and off by the pair of IGBTs provided as the lower arm switch A return path, which is a path of the winding, is cut off, and when the second energization control unit switches from a state in which the lower arm switch of the second inverter is opened and closed to a state in which the upper arm switch of the first inverter is opened and closed, the return path, which is a path including the upper arm switch of the second inverter and the second winding, is cut off by the pair of IGBTs provided as the upper arm switches.

According to the above aspect, in the first inverter, when the second energization control unit switches from the state in which the upper arm switch of the first inverter is opened and closed to the state in which the lower arm switch of the second inverter is opened and closed, the return path including the first winding is cut off by the pair of IGBTs provided as the lower arm switch. In the second inverter, when the second energization control unit switches from a state in which the lower arm switch of the second inverter is opened and closed to a state in which the upper arm switch of the first inverter is opened and closed, the return path including the second winding is cut off by the pair of IGBTs provided as the upper arm switch. This makes it possible to desirably perform commutation between the first winding side and the second winding side, and to appropriately perform complementary half-wave drive in each winding.

In addition, even if the lower arm switch of the first inverter and the upper arm switch of the second inverter are configured by a pair of IGBTs connected in parallel to each other, the number of switching elements that are turned on at the time of half-wave drive (i.e., the number of series elements on the conduction path) is not increased. Therefore, the conduction loss at the time of half-wave driving can be reduced.

According to the eighth aspect, when the current is controlled to the first winding and the second winding, the first current control unit performs the following operations: one of the pair of IGBTs of the first inverter is complementarily opened and closed with respect to the upper arm switch of the first inverter and the other IGBT is kept in a closed state, and one of the pair of IGBTs of the second inverter is complementarily opened and closed with respect to the lower arm switch of the second inverter and the other IGBT is kept in a closed state.

According to the above aspect, in the configuration having the pair of anti-parallel IGBTs as the lower arm switch of the first inverter and the pair of anti-parallel IGBTs as the upper arm switch of the second inverter, one of the pair of IGBTs of each inverter is opened and closed and the other is kept in the closed state during full-wave driving, thereby controlling the current. In this case, the full-wave drive can be appropriately performed by performing the reflux operation or the regeneration operation when the power factor is not 1.

In addition, in the configuration in which the pair of IGBTs are connected in anti-parallel (for example, the configuration in fig. 13), the number of series elements in the conduction path during full-wave driving can be reduced, and the conduction loss can be reduced, as compared with the configuration in which the pair of IGBTs with a free wheeling diode are connected in anti-series (for example, the configuration in fig. 12).

According to the ninth aspect, the first winding and the second winding have the same number of turns, and the conductors of the same phase are accommodated in the same slot of the stator core.

According to the mode, the magnetic force combination degree of the first winding and the second winding can be improved. This reduces the current loss between the windings during half-wave driving, that is, reduces the current loss between the windings during the time when the upper arm switch of the first inverter and the lower arm switch of the second inverter are alternately opened and closed for each energization period, thereby improving the driving efficiency.

According to a tenth aspect, the first winding and the second winding are formed of a conductor having a rectangular cross section.

Since the first winding and the second winding are formed of conductors having a rectangular cross section, the conductors of the windings can be arranged in order in the slot. Therefore, the deviation of the magnetic coupling degree of each of the first winding and the second winding can be suppressed. This can further reduce the commutation loss between the windings appropriately.

Drawings

The above objects, other objects, features and advantages of the present invention will become more apparent with reference to the accompanying drawings and the following detailed description. The drawings are as follows.

Fig. 1 is a longitudinal sectional view of a rotating electric machine.

Fig. 2 is a cross-sectional view showing a rotor and a stator.

Fig. 3 is a diagram showing a state of housing a conductor in a stator.

Fig. 4 is a circuit diagram showing a control system of the rotating electric machine.

Fig. 5 is a timing chart for explaining an operation in the full-wave drive mode.

Fig. 6 is a timing chart for explaining the operation in the half-wave drive mode.

Fig. 7 is a time chart showing a time-series change in torque of the rotating electric machine.

Fig. 8 is a diagram illustrating a return path formed in each inverter.

Fig. 9 is a diagram showing the output of the rotating electric machine when full-wave driving is performed and the output of the rotating electric machine when half-wave driving is performed.

Fig. 10 is a diagram showing a first operation region in which full-wave driving is performed and a second operation region in which half-wave driving is performed.

Fig. 11 is a flowchart showing the mode switching process.

Fig. 12 is a circuit diagram showing a control system of a rotating electric machine according to a second embodiment.

Fig. 13 is a circuit diagram showing a control system of a rotating electric machine according to a third embodiment.

Fig. 14 is a circuit diagram showing a control system of a rotating electric machine according to a fourth embodiment.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings. The rotating electric machine in the present embodiment is used as a vehicle power source, for example. However, the rotating electric machine is widely used for industrial use, vehicles, ships, aircrafts, home appliances, OA equipment, games, and the like. In the following embodiments, the same or equivalent portions are denoted by the same reference numerals in the drawings, and the description thereof will be referred to for the portions having the same reference numerals.

(first embodiment)

The rotating electric machine 10 of the present embodiment is an inner rotor type (inner rotor type) multiphase ac motor, and fig. 1 and 2 schematically show the same. Fig. 1 is a longitudinal sectional view of a rotary electric machine 10 in a direction along a rotary shaft 11, and fig. 2 is a sectional view showing a cross section of a rotor 12 and a stator 13 in a direction orthogonal to the rotary shaft 11. In the following description, a direction in which the rotary shaft 11 extends is defined as an axial direction, a direction in which the rotary shaft 11 radially extends with respect to the center is defined as a radial direction, and a direction in which the rotary shaft 11 circumferentially extends with respect to the center is defined as a circumferential direction.

The rotating electric machine 10 includes: a rotor 12 fixed to the rotating shaft 11; a stator 13 provided at a position surrounding the rotor 12; and a housing 14 for housing the rotor 12 and the stator 13. The rotor 12 and the stator 13 are coaxially arranged. The housing 14 has a pair of cylindrical housing members 14a, 14b, and the housing members 14a, 14b are integrated by fastening bolts 15 in a state where the opening portions are joined to each other. The housing 14 is provided with bearings 16 and 17, and the rotary shaft 11 and the rotor 12 are rotatably supported by the bearings 16 and 17.

The rotor 12 has a rotor core 21, and a plurality of permanent magnets 22 are circumferentially arranged in parallel on an outer peripheral portion of the rotor core 21 (i.e., on a side facing an inner peripheral portion of the stator 13 in a radial direction). The rotor core 21 is configured by laminating a plurality of electromagnetic steel plates in the axial direction and fixing the electromagnetic steel plates by caulking or the like.

A plurality of permanent magnets 22 are provided on the outer peripheral surface of the rotor core 21 so that magnetic poles alternate in the circumferential direction. In the present embodiment, a quadrupole surface magnet type structure is used as the rotor structure. However, the rotor 12 may be of an embedded magnet type. The permanent magnet may be a rare earth magnet or a ferrite magnet.

The stator 13 includes: an annular stator core 31; and six-phase (U1 phase, V1 phase, W1 phase, U2 phase, V2 phase, and W2 phase) stator windings 33 wound around the plurality of slots 32 of the stator core 31. The stator winding 33 has two sets of three-phase symmetrical windings. The stator core 31 is configured by laminating a plurality of annular electromagnetic steel plates in the axial direction and fixing the annular electromagnetic steel plates by caulking or the like. The stator core 31 includes an annular yoke 34 and a plurality of pole teeth 35 extending radially inward from the yoke 34 and arranged circumferentially at equal intervals, and a slot 32 is formed between adjacent pole teeth 35.

In the present embodiment, the rotating electrical machine 10 has a four-pole twenty-four slot structure and a six-phase structure having two sets of three-phase windings. That is, the stator winding 33 includes, as two sets of three-phase windings: a first winding 33a having windings of respective phases of U1 phase, V1 phase and W1 phase; and a second winding 33b (refer to fig. 4) having windings of the respective phases of U2 phase, V2 phase, and W2 phase.

In this case, as shown in fig. 3, in the stator 13, one phase is formed by two slots that are continuous in the circumferential direction, and four conductors are inserted into each slot 32 in a state where the first winding 33a and the second winding 33b are mixed. That is, four layers of conductors are accommodated radially inside and outside each slot 32, and the conductor on the first winding 33a side and the conductor on the second winding 33b side are alternately arranged. In this case, the first winding 33a and the second winding 33b have the same number of turns and are accommodated in the same slot 32 for each phase. The windings 33a and 33b are formed of flat wires (i.e., conductors having a rectangular cross section), and the windings 33a and 33b are arranged in the slots 32 in a radially inward and outward arrangement.

For example, in the slots 32 of #1 and #2, the conductors of the respective windings 33a and 33b are accommodated in the order of U2 → U1 → U2 → U1 from the radially inner side (i.e., the rotor 12 side), in the slots 32 of #3 and #4, the conductors of the respective windings 33a and 33b are accommodated in the order of V1 → V2 → V1 → V2 from the radially inner side, and in the slots 32 of #5 and #6, the conductors of the respective windings 33a and 33b are accommodated in the order of W2 → W1 → W2 → W1 from the radially inner side. According to the above configuration, in each slot 32, the conductor on the first winding 33a side and the conductor on the second winding 33b side are magnetically coupled to each other for each phase.

The number of poles, the number of phases, the number of slots, and the number of layers of conductors are not limited to these, and in short, the first winding 33a and the second winding 33b may be wound around the stator core 31, and the windings 33a and 33b may be magnetically coupled to each other for each phase in the wound state.

Next, the configuration of a control system for controlling the rotating electric machine 10 will be described with reference to fig. 4. In fig. 4, two sets of three-phase windings (i.e., a first winding 33a and a second winding 33b) are shown as the stator windings 33, and a first inverter 40 and a second inverter 50 are provided for the windings 33a and 33b, respectively. The inverters 40 and 50 are constituted by a full bridge circuit having upper and lower arms, the number of which is the same as the number of phases of the windings 33a and 33b, and the current flowing through the windings 33a and 33b is adjusted by turning on and off switches (semiconductor switching elements) provided in the arms.

Specifically, the first inverter 40 includes a series connection body of an upper arm switch 41 and a lower arm switch 42 in three phases composed of a U1 phase, a V1 phase, and a W1 phase, respectively. The high-potential-side terminal of the upper arm switch 41 of each phase is connected to the positive terminal of the dc power supply 60, and the low-potential-side terminal of the lower arm switch 42 of each phase is connected to the negative terminal (ground) of the dc power supply 60. The upper arm switch 41 and the lower arm switch 42 are semiconductor switching elements, more specifically, IGBTs having free wheeling diodes 43, 44 connected in a direction to be antiparallel, respectively. That is, the free wheeling diodes 43 and 44 are provided in a direction in which the cathode is on the high potential side and the anode is on the low potential side, respectively.

At an intermediate point between the upper arm switch 41 and the lower arm switch 42 of each phase, one end of the U1 phase winding, the V1 phase winding, and the W1 phase winding are connected via the additional switch 45, respectively. That is, the additional switch 45 corresponds to a "first additional switch", and the ac line connecting the intermediate point of each of the switches 41 and 42 of the upper and lower arms in the first inverter 40 and the winding portion of the first winding 33a for each phase is turned on or off by the additional switch 45. The additional switch 45 is a semiconductor switching element formed of, for example, an IGBT. In the additional switch 45, a free wheeling diode 46 is provided in a direction in which the midpoint side of each of the switches 41 and 42 of the upper and lower arms is a cathode and the winding portion side for each phase is an anode.

The respective phase windings of the first winding 33a are star-connected (Y-connected), and the other ends of the respective phase windings are connected to each other at a neutral point N1. The neutral point N1 is connected to the low potential side of the dc power supply 60 via a current path 47, and a changeover switch 48 is provided on the current path 47. The changeover switch 48 corresponds to a "first changeover switch", and the neutral point N1 is turned on or off from the low potential side of the dc power supply 60 by the changeover switch 48. The changeover switch 48 is a semiconductor switching element formed of, for example, an IGBT. In the changeover switch 48, a reflux diode 49 is provided in a direction such that the neutral point N1 side is a cathode and the low potential side of the dc power supply 60 is an anode.

The second inverter 50 has the same configuration as the first inverter 40, and includes a series connection body of an upper arm switch 51 and a lower arm switch 52 in each of three phases including a U2 phase, a V2 phase, and a W2 phase. The high-potential-side terminal of the upper arm switch 51 of each phase is connected to the positive terminal of the dc power supply 60, and the low-potential-side terminal of the lower arm switch 52 of each phase is connected to the negative terminal of the dc power supply 60 (grounded). The upper arm switch 51 and the lower arm switch 52 are semiconductor switching elements, and more specifically, are IGBTs having free wheeling diodes 53, 54 connected in a direction to become antiparallel, respectively. That is, the free wheeling diodes 53 and 54 are provided in a direction in which the cathode is on the high potential side and the anode is on the low potential side, respectively.

At an intermediate point between the upper arm switch 51 and the lower arm switch 52 of each phase, one end of the U2 phase winding, the V2 phase winding, and the W2 phase winding are connected via the additional switch 55, respectively. That is, the additional switch 55 corresponds to a "second additional switch", and the ac line connecting the intermediate point of each of the switches 51 and 52 of the upper and lower arms in the second inverter 50 and the winding portion of the second winding 33b for each phase is turned on or off by the additional switch 55. The additional switch 55 is a semiconductor switching element formed of, for example, an IGBT. In the additional switch 55, a free wheeling diode 56 is provided in a direction in which the midpoint side of each of the switches 51 and 52 of the upper and lower arms is a cathode and the winding portion side for each phase is an anode.

The respective phase windings of the second winding 33b are star-connected (Y-connected), and the other ends of the respective phase windings are connected to each other at a neutral point N2. The neutral point N2 is connected to the high potential side of the dc power supply 60 via a current path 57, and a changeover switch 58 is provided on the current path 57. The changeover switch 58 corresponds to a "second changeover switch", and the neutral point N2 is turned on or off from the high potential side of the dc power supply 60 by the changeover switch 58. The changeover switch 58 is a semiconductor switching element formed of, for example, an IGBT. In the changeover switch 58, a reflux diode 59 is provided in a direction such that the neutral point N2 side is an anode and the high potential side of the dc power supply 60 is a cathode.

The control device 65 includes a microcomputer including a CPU and various memories, and performs energization control by opening and closing (turning on and off) of the switches of the inverters 40 and 50 based on various kinds of detection information in the rotating electric machine 10 and requests for power running drive and power generation. The detection information of the rotating electrical machine 10 includes: for example, the rotation angle (electrical angle information) of the rotor 12 detected by an angle detector such as a resolver, the power supply voltage (inverter input voltage) detected by a voltage sensor, and the conduction current of each phase detected by a current sensor. The control device 65 generates and outputs operation signals for operating the switches of the inverters 40 and 50.

In the present embodiment, the energization of the first winding 33a and the second winding 33b of the rotating electrical machine 10 is controlled by the first inverter 40 and the second inverter 50, respectively. In this case, in particular, the drive of the rotating electrical machine 10 is controlled in the full-wave drive mode by turning the changeover switches 48 and 58 to the on state (off state), and the drive of the rotating electrical machine 10 is controlled in the half-wave drive mode by turning the changeover switches 48 and 58 to the off state (on state). That is, switching between the full-wave drive mode and the half-wave drive mode, which are drive modes of the rotary electric machine 10, is performed by switching the selector switches 48 and 58 between the on state and the off state. In the present embodiment, the control device 65 constitutes a first energization control unit and a second energization control unit.

Fig. 5 shows a control method of each switch in the full-wave drive mode, and fig. 6 shows a control method of each switch in the half-wave drive mode. Although fig. 5 and 6 show only the W1 phase and the W2 phase in the two-phase three-stator winding 33, the same operation is performed in the other phases of the windings 33a and 33b, which are different in electrical angle by 120 degrees.

As shown in fig. 5, in the full-wave drive mode, the changeover switches 48 and 58 are turned off, and the additional switches 45 and 55 of the inverters 40 and 50 are turned on. Further, the energization of the first winding 33a is controlled by complementarily turning on and off the upper arm switch 41 and the lower arm switch 42 in the first inverter 40. Further, the energization of the second winding 33b is controlled by complementarily turning on and off the upper arm switch 51 and the lower arm switch 52 in the second inverter 50. In short, in the full-wave drive mode, the energization of the first winding 33a and the second winding 33b is controlled by opening and closing the switches of the upper and lower arms in the inverters 40 and 50 in a complementary manner during the same energization period.

According to the energization control in the full-wave drive mode, in the winding portions of the W1 phase and the W2 phase of the same phase, as shown in the drawing, the W1 current and the W2 current are made to flow in the same phase, and the rotary electric machine 10 is driven by the resultant current, i.e., "W1 + W2 current". In this case, the stator winding 33 is energized with the three-phase ac current of the full wave shape by controlling energization of the two sets of winding portions of the same phase during the same energization period. This enables high torque output.

On the other hand, as shown in fig. 6, in the half-wave drive mode, the switching switches 48, 58 are turned on, and the additional switch 45 of the first inverter 40 and the additional switch 55 of the second inverter 50 are alternately turned on at a 180-degree cycle (half electric cycle). Further, while the additional switches 45, 55 are on, the upper arm switch 41 of the first inverter 40 is turned on and off, and the lower arm switch 52 of the second inverter 50 is turned on and off.

In detail, during the period T1, the additional switch 45 of the first inverter 40 is turned on, and the additional switch 55 of the second inverter 50 is turned off. In this state, in the first inverter 40, the upper arm switch 41 is turned on and off and the lower arm switch 42 is kept off, and in the second inverter 50, both the upper arm switch 51 and the lower arm switch 52 are kept off.

Further, during the period T2, the additional switch 45 of the first inverter 40 is turned off, and the additional switch 55 of the second inverter 50 is turned on. In this state, in the first inverter 40, both the upper arm switch 41 and the lower arm switch 42 are kept off, and in the second inverter 50, the upper arm switch 51 is kept off and the lower arm switch 42 is turned on and off.

In short, in the half-wave drive mode, the upper arm switch 41 of the switches 41 and 42 of the upper and lower arms of the first inverter 40 and the lower arm switch 52 of the switches 51 and 52 of the upper and lower arms of the second inverter 50 are alternately opened and closed for a predetermined energization period (T1, T2) with the switching switches 48 and 58 closed. Thereby, the energization of the first winding 33a and the second winding 33b is controlled.

The inverter 40 and the inverter 50 alternately perform half-wave driving of the rotating electric machine 10 according to the energization control in the half-wave driving mode. In this case, in the stator 13, the first winding 33a and the second winding 33b are magnetically coupled to each other, and the low potential side of the neutral point N1 and the dc power supply 60 is short-circuited by the changeover switch 48 on the first winding 33a side, and the high potential side of the neutral point N2 and the dc power supply 60 is short-circuited by the changeover switch 58 on the second winding 33b side, so that the directions of the phase currents are opposite to each other and change positively and negatively during the energization period of the first winding 33a and the energization period of the second winding 33b, respectively. Further, by setting the energization period of the first winding 33a and the energization period of the second winding 33b to be different from each other, the resultant magnetomotive force of the windings 33a, 33b is made to be in a full wave shape.

That is, as shown in fig. 6, in the period T1, a negative current initially flows as W1 current but gradually changes to a positive current, whereas in the period T2, a positive current initially flows as W1 current but gradually changes to a negative current. Thus, although the half-wave drive is performed, the combined current (W1+ W2 current) of the W1 current and the W2 current has a sine wave waveform or a waveform close to the sine wave waveform. That is, a sinusoidal rotating magnetic field (magnetomotive force) can be obtained as in the case of full-wave driving.

Fig. 7 is a time chart showing a time-series change in the torque of the rotating electric machine 10, in which a solid line shows a change in the torque in the present embodiment and a dashed-dotted line shows a change in the torque in the conventional example. From fig. 7, it is understood that the torque ripple is reduced and the average torque is raised (AVE1 → AVE 2).

In switching between the half-wave drive in the first inverter 40 and the half-wave drive in the second inverter 50, a commutation by magnetic induction is performed between the winding portions magnetically coupled to each other, which will be described later.

When the upper arm switch 41 of the first inverter 40 is switched so that a half-wave current flows through the first winding 33a, a positive current flows in a direction from the upper arm switch 41 toward the neutral point N1 of the first winding 33a via the additional switch 45. In the above case, for example, at time ta in fig. 6, when the upper arm switch 41 and the additional switch 45 are turned off to cut off the current of the first winding 33a, a voltage is generated in the first winding 33a and the second winding 33b in a direction to prevent the current from changing. Thus, a current path is formed on the second winding 33b side through the second winding 33b, the changeover switch 58, the dc power supply 60, the reflux diode 54 of the lower arm switch 52, the reflux diode 53 of the upper arm switch 51, and the second winding 33b, and the current flowing through the first winding 33a flows into the second winding 33 b.

Next, the additional switch 55 is turned on, and the switching of the lower arm switch 52 of the second inverter 50 is started, thereby causing a half-wave current to flow through the second winding 33 b. The same applies to the case where the current is transferred from the second winding 33b to the first winding 33 a. However, as a different point, when a half-wave current flows through the second winding 33b, the current direction is opposite to that when the first winding 33a is energized to flow a negative current from the neutral point N2 of the second winding 33b in the direction toward the lower arm switch 52 via the additional switch 55.

Further, as described above, for example, when the upper arm switch 41 of the first inverter 40 is switched to cause a half-wave current to flow through the first winding 33a, the current of the first winding 33a is cut off, and the current is transferred to the second winding 33b side, but a return path is formed in the first inverter 40 immediately after the current is cut off, and therefore there is a possibility that the current is prevented from being transferred. That is, as shown in fig. 8, a return path R1, which is a path including the return diode 44 of the lower arm switch 42 and the first winding 33a, is formed on the first inverter 40 side. When the current of the second winding 33b is cut off, a return path R2 is formed on the second inverter 50 side as a path including the return diode 53 of the upper arm switch 51 and the second winding 33 b. In addition, fig. 8 shows a return flow path R1 passing through the winding portion of the W1 phase and a return flow path R2 passing through the winding portion of the W2 phase.

In this regard, when the switching of the upper arm switch 41 of the first inverter 40 is stopped and the switching of the lower arm switch 52 of the second inverter 50 is started, the additional switch 45 is turned off in accordance with the stop of the switching of the upper arm switch 41. Therefore, the return path R1 is cut off by the additional switch 45. When switching of the lower arm switch 52 of the second inverter 50 is stopped and switching of the upper arm switch 41 of the first inverter 40 is started, the additional switch 55 is turned off in accordance with the stop of the switching of the lower arm switch 52. Therefore, the return path R2 is cut off by the additional switch 55. The additional switch 45 corresponds to a "first cut-off portion", and the additional switch 55 corresponds to a "second cut-off portion".

In the first inverter 40, the lower arm switch 42 and the additional switch 45 are connected in series in directions opposite to each other, and the two switches 42 and 45 constitute a bidirectional switch capable of bidirectional energization and bidirectional interruption. In the second inverter 50, the upper arm switch 51 and the additional switch 55 are connected in series in directions opposite to each other, and the two switches 51 and 55 constitute a bidirectional switch capable of bidirectional energization and bidirectional interruption.

The control device 65 switches the full-wave drive mode and the half-wave drive mode based on the rotation speed of the rotating electrical machine 10. Specifically, in the low-rotation-side operation region of the rotary electric machine 10, the control device 65 turns off (opens) the change-over switches 48 and 58, and performs energization control of the windings 33a and 33b in the full-wave drive mode. In the operating region on the high rotation side of the rotating electrical machine 10, the switching switches 48 and 58 are turned on (closed), and the energization control of the windings 33a and 33b is performed in the half-wave drive mode.

In fig. 9, the output of the rotating electric machine when full-wave driving is performed is indicated by a solid line, and the output of the rotating electric machine when half-wave driving is performed is indicated by a broken line. The full-wave drive is more suitable for high-torque operation because the magnetomotive force is doubled as compared with the half-wave drive. Compared with full-wave driving, half-wave driving is more suitable for high rotation operation because the applied voltage per unit winding is twice as high. In this case, when the full-wave drive and the half-wave drive are performed, the output characteristics partially overlap. Therefore, in the present embodiment, as shown in fig. 10, the first operation region for full-wave driving and the second operation region for half-wave driving are determined, and mode switching is performed according to the operation regions. In fig. 10, the first operation region is shaded.

Fig. 11 is a flowchart showing a mode switching process performed by the control device 65, and this process is repeatedly performed at a predetermined cycle.

In step S11, it is determined whether or not the operating state of the rotary electric machine 10 has entered the first operating region, and in step S12, it is determined whether or not the operating state of the rotary electric machine 10 has entered the second operating region. In steps S11 and S12, for example, it is preferable to determine the operation region based on the rotational speed calculated using the rotational information of the rotor 12 and the requested torque for the rotating electrical machine 10.

When the operating state of the rotating electrical machine 10 enters the first operating region, the process proceeds to step S13, and it is determined that the rotating electrical machine 10 is driven in the full-wave drive mode. In this case, the changeover switches 48, 58 are turned off. In addition, the additional switches 45 and 55 of the inverters 40 and 50 are turned on, and the upper and lower arm switches of each phase are switched to perform full-wave driving.

When the operating state of the rotary electric machine 10 enters the second operating region, the process proceeds to step S14, and it is determined that the rotary electric machine 10 is driven in the half-wave drive mode. In this case, the changeover switches 48, 58 are turned on. In each phase, the additional switches 45 and 55 of the inverters 40 and 50 are alternately turned on every half electric cycle, and the upper arm switch 41 is switched in the first inverter 40 and the lower arm switch 52 is switched in the second inverter 50, thereby performing half-wave drive.

According to the present embodiment described in detail above, the following excellent effects can be obtained.

In the full-wave drive mode, the switching switches 48 and 58 are turned off (opened), and full-wave energization of the first winding 33a and the second winding 33b is performed by the first inverter 40 and the second inverter 50. In this case, the energization control is performed for the same energization period for the same phase winding portions in the first winding 33a and the second winding 33b, thereby achieving high torque output.

In the half-wave drive mode, the switching switches 48 and 58 are turned on (closed), and the first inverter 40 and the second inverter 50 perform half-wave energization of the first winding 33a and the second winding 33 b. In this case, the first winding 33a and the second winding 33b are magnetically coupled to each other, and the neutral point N1 is short-circuited to the low potential side of the dc power supply 60 by the changeover switch 48 on the first winding 33a side, and the neutral point N2 is short-circuited to the high potential side of the dc power supply 60 by the changeover switch 58 on the second winding 33b side, so that the directions of the phase currents are opposite to each other during the energization period of the windings 33a and 33b, and a full-wave magnetomotive force can be obtained from the combined magnetomotive force of the windings 33a and 33 b. In summary, it is possible to desirably perform full-wave driving and half-wave driving, and reduce torque ripple at the time of half-wave driving.

Since the switches 48 and 58 are opened and closed in accordance with the operation region of the rotating electric machine 10, different output characteristics can be obtained as desired, and the efficient operation region of the rotating electric machine 10 can be expanded. In the state where the switches 48 and 58 are closed, the applied voltage per unit winding is higher in the winding portion of each phase than in the full-wave driving. Therefore, an advantageous configuration can be realized while expanding the operation region of the rotating electric machine 10 toward the high rotation region side.

In the half-wave drive mode, when the half-wave conduction by the first inverter 40 and the half-wave conduction by the second inverter 50 are switched, the return paths R1, R2 formed by the return diodes of the arm switches and the windings 33a, 33b are cut off by the additional switches 45, 55. This makes it possible to desirably perform commutation between the first winding 33a side and the second winding 33b side, and to appropriately perform complementary half-wave drive in the windings 33a and 33 b.

Specifically, in each of the inverters 40 and 50, the additional switches 45 and 55 are provided on the ac lines connecting the intermediate points of the upper and lower arms to the winding portions of each phase, so that the return paths formed when switching to the half-wave conduction can be cut off by the additional switches 45 and 55 as desired. Thus, complementary half-wave drive in the winding that becomes the power-on side can still be appropriately performed.

Since the first winding 33a and the second winding 33b have the same number of turns and the same phase conductor is accommodated in the same slot 32 of the stator core 31, the magnetic coupling degree between the first winding 33a and the second winding 33b can be improved. This reduces the turn loss between the windings during half-wave driving, that is, reduces the turn loss between the windings when the upper arm switch 41 of the first inverter 40 and the lower arm switch 52 of the second inverter 50 are alternately opened and closed for each energization period, thereby improving the driving efficiency.

Since the first winding 33a and the second winding 33b are formed by conductors having a rectangular cross section, the conductors of the windings 33a and 33b can be arranged in order in the slot 32. Therefore, the deviation of the magnetic coupling degree of each of the first and second windings 33a and 33b can be suppressed. This can further reduce the commutation loss between the windings appropriately.

Since the rotating electric machine 10 is configured to include two sets of windings and inverters, the drive system can be made redundant, and the reliability of the system can be improved.

Hereinafter, second to fourth embodiments in which the configurations of a part of the first inverter 40 and the second inverter 50 are changed will be described. Note that the same reference numerals are given to the same portions as those of the first embodiment as the configuration of the control system, and the description thereof is omitted. For convenience, the description of the control device 65 is also omitted.

(second embodiment)

Fig. 12 is a circuit diagram showing a control system of a rotating electric machine according to a second embodiment. In fig. 12, in the first inverter 40, a pair of semiconductor switching elements 42a, 42b are provided as the lower arm switch 42 of each phase, the semiconductor switching elements 42a, 42b are connected in series with each other, and have free wheeling diodes 44a, 44b provided in reverse directions to each other. The pair of semiconductor switching elements 42a and 42b are reverse conducting semiconductor switching elements connected in anti-series, and function as a bidirectional switch capable of bidirectional conduction and bidirectional disconnection. In the present embodiment, the pair of semiconductor switching elements 42a and 42b corresponds to a "first cut portion".

Further, in the second inverter 50, a pair of semiconductor switching elements 51a, 51b are provided as the upper arm switch 51 of each phase, the semiconductor switching elements 51a, 51b are connected in series with each other, and have free wheeling diodes 53a, 53b provided in reverse directions to each other. The pair of semiconductor switching elements 51a and 51b are reverse conducting type semiconductor switching elements connected in anti-series, and function as a bidirectional switch capable of bidirectional conduction and bidirectional disconnection. In the present embodiment, the pair of semiconductor switching elements 51a and 51b corresponds to a "second cut-off unit".

The configurations of the upper arm switch 41 of the first inverter 40 and the lower arm switch 52 of the second inverter 50 are the same as those of fig. 4.

In the above configuration, when the inverters 40 and 50 are driven in full-wave, the controller 65 causes one semiconductor switching element 42a (i.e., the semiconductor switching element having the same direction as the upper arm switch 41 as the free-wheeling diode) of the pair of semiconductor switching elements 42a and 42b of the lower arm switch 42 in the first inverter 40 to be complementarily opened and closed with respect to the upper arm switch 41, and causes the other semiconductor switching element 42b to be maintained in an on state (off state). In the second inverter 50, one semiconductor switching element 51a (i.e., the semiconductor switching element having the same direction as that of the lower arm switch 52 as the free wheeling diode) of the pair of semiconductor switching elements 51a, 51b as the upper arm switch 51 is complementarily opened and closed with respect to the lower arm switch 52, and the other semiconductor switching element 51b is held in an on state (off state).

Further, when half-wave driving is performed by the first inverter 40 in the half-wave driving mode, the control device 65 switches the upper arm switch 41 while keeping the semiconductor switching element 42a of the pair of semiconductor switching elements 42a, 42b in an off state (on state) and keeping the semiconductor switching element 42b in an on state (off state). Each of the switches 51, 52 on the second inverter 50 side is maintained in an off state (open state).

Further, as the half electric cycle elapses, the control device 65 stops switching the upper arm switch 41, and brings both the pair of semiconductor switching elements 42a, 42b into the off state (on state). Further, the lower arm switch 52 in the second inverter 50 starts to be switched. When the lower arm switch 52 is switched, the semiconductor switching element 51a of the pair of semiconductor switching elements 51a, 51b is kept in an off state (on state), and the semiconductor switching element 51b is kept in an on state (off state).

In contrast to the operation shown in fig. 6 described in the first embodiment, the semiconductor switching element 42a operates in the same manner as the lower arm switch 42, and the semiconductor switching element 42b operates in the same manner as the additional switch 45. The semiconductor switching element 51a operates similarly to the upper arm switch 51, and the semiconductor switching element 51b operates similarly to the additional switch 55.

Here, when switching from the state of half-wave driving by the first inverter 40 to the state of half-wave driving by the second inverter 50, the pair of semiconductor switching elements 42a and 42b are turned off, and bidirectional conduction is interrupted by the mutually opposite free wheeling diodes 44a and 44b in this state. Therefore, when the switching of the upper arm switch 41 is stopped, the return path R1 (see fig. 8) in the first inverter 40 is cut off.

Similarly, when switching from the state of half-wave driving by the second inverter 50 to the state of half-wave driving by the first inverter 40, the pair of semiconductor switching elements 51a and 51b are turned off, and bidirectional conduction is interrupted by the mutually opposite return diodes 53a and 53b in this state. Therefore, when switching of the lower arm switch 52 is stopped, the return path R2 (see fig. 8) in the second inverter 50 is cut off.

In the present embodiment, as compared with the configuration of fig. 4 of the first embodiment, the number of series elements in the on state during full-wave driving can be reduced, and the on loss can be reduced.

During full-wave driving, one of the pair of semiconductor switching elements (i.e., the lower arm switch 42 of the first inverter 40 and the upper arm switch 51 of the second inverter 50) connected in anti-series is opened and closed in each of the inverters 40 and 50, and the other is kept in a closed state, thereby controlling the current. In this case, the full-wave drive can be appropriately performed by performing the reflux operation or the regeneration operation when the power factor is not 1.

(third embodiment)

Fig. 13 is a circuit diagram showing a control system of a rotating electric machine according to a third embodiment. In fig. 13, the first inverter 40 is provided with a pair of IGBTs 42c, 42d connected in reverse parallel with each other as the lower arm switch 42 of each phase. The pair of IGBTs 42c, 42d are reverse-resistance IGBTs connected in antiparallel, and function as a bidirectional switch capable of bidirectional energization and bidirectional interruption. More specifically, the collector of one IGBT42c is on the high potential side and the emitter is on the low potential side, and the emitter of the other IGBT42d is on the high potential side and the collector is on the low potential side, and the pair of IGBTs 42c and 42d are connected in anti-parallel with each other.

The second inverter 50 is provided with a pair of IGBTs 51c, 51d connected in parallel in reverse to each other as the upper arm switch 51 of each phase. The pair of IGBTs 51c, 51d are reverse-resistance IGBTs connected in antiparallel, and function as a bidirectional switch capable of bidirectional energization and bidirectional interruption. More specifically, the collector of one IGBT51c is on the high potential side and the emitter is on the low potential side, and the emitter of the other IGBT51d is on the high potential side and the collector is on the low potential side, and the pair of IGBTs 51c and 52d are connected in anti-parallel with each other.

The configurations of the upper arm switch 41 of the first inverter 40 and the lower arm switch 52 of the second inverter 50 are the same as those of fig. 4.

In the above configuration, when the inverters 40 and 50 are driven in full-wave, the controller 65 causes one IGBT42c (i.e., the IGBT whose collector is connected to the upper arm switch 41) of the pair of IGBTs 42c and 42d as the lower arm switch 42 in the first inverter 40 to open and close complementarily to the upper arm switch 41, and causes the other IGBT42d to be kept in an on state (off state). In the second inverter 50, one IGBT51c (i.e., the IGBT whose emitter is connected to the lower arm switch 52) of the pair of IGBTs 51c, 51d as the upper arm switch 51 is complementarily opened and closed with respect to the lower arm switch 52, and the other IGBT51d is held in an on state (off state).

Further, when half-wave driving is performed with the first inverter 40 in the half-wave driving mode, the control device 65 switches the upper arm switch 41, and on the other hand, keeps the IGBT42c of the pair of IGBTs 42c, 42d in an off state (open state), and keeps the IGBT42d in an on state (closed state). Each of the switches 51, 52 on the second inverter 50 side is maintained in an off state (open state).

Further, as the half electric cycle elapses, the control device 65 stops switching the upper arm switch 41, and brings both the pair of IGBTs 42c, 42d into the off state (open state). Further, the lower arm switch 52 in the second inverter 50 starts to be switched. When the lower arm switch 52 is switched, the IGBT51c of the pair of IGBTs 51c, 51d is kept in an off state (on state), and the IGBT51d is kept in an on state (off state).

In contrast to the operation of fig. 6 described in the first embodiment, the IGBT42c operates in the same manner as the lower arm switch 42, and the IGBT42d operates in the same manner as the additional switch 45. The IGBT51c operates similarly to the upper arm switch 51, and the IGBT51d operates similarly to the additional switch 55.

Here, when switching from the state of half-wave driving by the first inverter 40 to the state of half-wave driving by the second inverter 50, the pair of IGBTs 42c, 42d are turned off to cut the bidirectional current. Therefore, when the switching of the upper arm switch 41 is stopped, the return path R1 (see fig. 8) in the first inverter 40 is cut off.

Similarly, when switching from the state of half-wave driving by the second inverter 50 to the state of half-wave driving by the first inverter 40, the pair of IGBTs 51c, 51d are turned off to cut the bidirectional current. Therefore, when switching of the lower arm switch 52 is stopped, the return path R2 (see fig. 8) in the second inverter 50 is cut off.

In summary, in the half-wave drive mode, the commutation between the first winding 33a side and the second winding 33b side can be desirably performed, so that the complementary half-wave drive in each of the windings 33a, 33b can be appropriately performed.

In addition, even if the lower arm switch 42 of the first inverter 40 and the upper arm switch 51 of the second inverter 50 are configured by a pair of IGBTs connected in parallel to each other, the number of switching elements that are turned on at the time of half-wave drive (i.e., the number of series elements on the conduction path) is not increased. Therefore, the conduction loss at the time of half-wave driving can be reduced.

In the present embodiment, during full-wave driving, one IGBT of a pair of IGBTs (i.e., the lower arm switch 42 of the first inverter 40 and the upper arm switch 51 of the second inverter 50) connected in anti-parallel is turned on and off in each of the inverters 40 and 50, and the other IGBT is kept in an off state, thereby controlling the current. In this case, the full-wave drive can be appropriately performed by performing the reflux operation or the regeneration operation when the power factor is not 1.

In the configuration in which the pair of IGBTs are connected in anti-parallel (the configuration in fig. 13), the number of series elements that are in a conductive state during full-wave driving can be reduced, and conduction loss can be reduced, as compared with the configuration in which the pair of IGBTs with free wheeling diodes are connected in anti-series (the configuration in fig. 12).

(fourth embodiment)

The configuration may be such that MOSFETs are used as switches of the inverters 40 and 50. Fig. 14 is a circuit diagram showing a control system of the rotating electric machine 10 according to the fourth embodiment. In fig. 14, MOSFETs 42e and 42f made of wide bandgap semiconductors are provided as the lower arm switch 42 of the first inverter 40 in a state of being connected in series in reverse. Further, as the upper arm switch 51 of the second inverter 50, MOSFETs 51e and 51f made of wide bandgap semiconductors are connected in series in reverse. As a result, the lower arm switch 42 of the first inverter 40 and the upper arm switch 51 of the second inverter 50 are provided with the bidirectional on/off function.

As a MOSFET made of a wide band gap semiconductor, a wide band gap semiconductor element made of SiC (silicon carbide) -based material, GaN (gallium nitride) -based material, or the like is preferably used. By using a wide band gap semiconductor element, the on-resistance can be reduced. According to the configuration of fig. 14, the conduction loss at the time of switching each switch in the full-wave drive mode can be further reduced.

(other embodiments)

For example, the above embodiment may be modified as described below.

As the changeover switches 48 and 58, a mechanical contact switch may be used in addition to the semiconductor switching element. For example, in an application where the low rotation operation region and the high rotation operation region are intermittently switched, the semiconductor switching element may not be used.

The number of turns of the first winding 33a may be different from that of the second winding 33 b. In this case, although the magnitude of the current flowing through the first winding 33a is different from the magnitude of the current flowing through the second winding 33b, half-wave driving can be performed.

The stator winding 33 is not limited to a three-phase winding, and may be a five-phase winding, for example, as long as it has a neutral point.

The two inverters 40 and 50 may be connected to separate dc power supplies.

The rotary electric machine 10 may be a rotary electric machine other than the magnet rotor structure, and may be a rotary electric machine of an induction rotor structure, for example. Further, instead of the inner rotor structure, an outer rotor structure may be employed.

Although the present invention has been described based on the embodiments, it should be understood that the present invention is not limited to the embodiments and the configurations described above. The present invention also includes various modifications and modifications within an equivalent range. In addition, various combinations and modes, and other combinations and modes including only one element, one or more elements, and one or less elements also belong to the scope and the idea of the present invention.