阅读说明：本技术 一种永磁同步电机及其切换开关 (Permanent magnet synchronous motor and change-over switch thereof ) 是由 李毅拓 陈西山 翟秀果 于 2019-09-26 设计创作，主要内容包括：本发明涉及一种永磁同步电机及其切换开关。切换开关包括：至少两组导电滑块,各导电滑块分别用于与定子绕组中不同匝数的绕组导电连接,相邻两组导电滑块之间设置有绝缘滑块,以使绝缘滑块与导电滑块围成封闭的环状结构；碳刷,可绕环状结构的中心转动,以逐次与导电滑块接触；驱动机构,配置有控制器,可根据电机转速大小带动碳刷转动,以使碳刷逐次与导电滑块导电接触。根据永磁同步电机定子绕组的结构,可扩大定子绕组中的分段段数,并根据转速大小调节接入定子绕组的匝数,无需弱磁扩速,可使电机在转速调节过程中具有较稳定的输出功率、较高的转速调节精度和输出效率；无需扩大环状结构的径向尺寸,使永磁同步电机可用在电动汽车上。(The invention relates to a permanent magnet synchronous motor and a change-over switch thereof. The change-over switch includes: the stator comprises at least two groups of conductive sliding blocks, wherein each conductive sliding block is respectively used for being in conductive connection with windings with different turns in a stator winding, and an insulating sliding block is arranged between every two adjacent groups of conductive sliding blocks so that the insulating sliding blocks and the conductive sliding blocks form a closed annular structure; the carbon brush can rotate around the center of the annular structure so as to be contacted with the conductive sliding block successively; the driving mechanism is provided with a controller and can drive the carbon brush to rotate according to the rotating speed of the motor so as to enable the carbon brush to be in conductive contact with the conductive sliding block successively. According to the structure of the stator winding of the permanent magnet synchronous motor, the number of the segmented segments in the stator winding can be enlarged, the number of turns connected into the stator winding is adjusted according to the rotating speed, the flux weakening and speed expansion are not needed, and the motor can have stable output power, high rotating speed adjusting precision and high output efficiency in the rotating speed adjusting process; the radial size of the annular structure does not need to be enlarged, so that the permanent magnet synchronous motor can be used on an electric automobile.)

1. A change-over switch of a permanent magnet synchronous motor, comprising:

the conductive sliding blocks are arranged at intervals, each group of conductive sliding blocks comprises three-phase sliding blocks arranged at intervals so as to respectively correspond to three phases of the stator winding, each conductive sliding block is respectively used for being in conductive connection with windings with different turns in the stator winding, and an insulating sliding block is arranged between every two adjacent groups of conductive sliding blocks so that the insulating sliding blocks and the conductive sliding blocks form a closed annular structure;

the carbon brush can rotate around the center of the annular structure so as to be in conductive contact with the conductive sliding block successively;

and the driving mechanism is in transmission connection with the carbon brushes and is provided with a controller which can be used for driving the carbon brushes to rotate according to the rotating speed of the permanent magnet synchronous motor so that the carbon brushes are in conductive contact with each group of conductive sliding blocks successively.

2. The change-over switch of a permanent magnet synchronous motor according to claim 1, further comprising an annular housing for being disposed on a rear end cover of the permanent magnet synchronous motor, wherein the conductive slider and the insulating slider are both fixed on the annular housing.

3. The change-over switch for a permanent magnet synchronous motor according to claim 1 or 2, wherein the driving mechanism is based on a rear end cover of the permanent magnet synchronous motor and is disposed corresponding to a central position of the ring structure.

4. The change-over switch for a permanent magnet synchronous motor according to claim 1 or 2, wherein the maximum number of sets N ═ N x (Q/3) of said conductive sliders can be set, where N is the number of series turns of each winding element in the stator winding and Q is the number of slots of the stator winding.

5. The diverter switch according to claim 1 or 2, wherein said conductive and insulating sliders are equidistant from the center of the ring structure.

6. The change-over switch for a permanent magnet synchronous motor according to claim 1 or 2, wherein the insulating sliders between two adjacent sets of the conductive sliders are of an integrated structure, and the number of sets of the insulating sliders is equal to the number of sets of the conductive sliders.

7. The diverter switch according to claim 1 or 2, wherein said three-phase sliders are arranged along a line parallel to the central axis of said ring structure.

8. The change-over switch for a permanent magnet synchronous motor according to claim 1 or 2, wherein a central angle of the conductive slider is equal to a central angle of a contact surface of the carbon brush with the annular structure.

9. The change-over switch for the PMSM according to claim 1 or 2, wherein the conductive slider includes a high conductive slider corresponding to the PMSM at the lowest speed and in contact with the carbon brush, the high conductive slider is used to connect the most turns in the stator winding, and a low conductive slider corresponding to the PMSM at the highest speed and in contact with the carbon brush, the low conductive slider is used to connect the least turns in the stator winding, the low conductive slider is adjacent to the high conductive slider, and a limit stop is provided between the two conductive sliders to limit the carbon brush from directly switching between the two conductive sliders.

10. A permanent magnet synchronous machine comprising a stator winding and a machine housing, characterized by further comprising a change-over switch for switching the number of turns of a coil inserted into the stator winding, the change-over switch being the change-over switch of the permanent magnet synchronous machine according to any one of claims 1 to 9.

Technical Field

The invention relates to a permanent magnet synchronous motor and a change-over switch thereof.

Background

In order to meet the requirement of maintaining constant-power operation in a wide rotating speed range, a flux weakening and speed expansion method is basically adopted for the existing permanent magnet synchronous motor of the electric automobile, because the back electromotive force of the permanent magnet synchronous motor is in direct proportion to the rotating speed, the back electromotive force of the permanent magnet synchronous motor reaches the system limit after the rotating speed reaches a certain value, and a higher-speed operating interval can only inhibit the rise of the back electromotive force by means of reverse direct-axis current in a stator, namely, in a high rotating speed interval of the motor, the direct-axis component flux weakening of the stator current does negative work, and the negative work of the part is increasingly larger along with the rise of the rotating speed, so that the output efficiency of the motor in the.

In order to avoid using a weak magnetic speed expanding method to improve the output efficiency of a high-speed interval motor, in the prior art, a method of reducing the number of turns of a part of stator windings is adopted to reduce the counter electromotive force when a few permanent magnet synchronous motors run at a high speed, the stator windings are led out in sections and connected to a relay, and the working turns of the motor windings are controlled by the relay.

Disclosure of Invention

The invention aims to provide a change-over switch of a permanent magnet synchronous motor, which aims to solve the technical problems that the motor rotating speed adjusting precision is low and the output power is unstable in the motor rotating speed adjusting process due to limited sections when a stator winding of the motor is led out in sections in the prior art; correspondingly, the invention also aims to provide a permanent magnet synchronous motor, so as to solve the technical problem that the permanent magnet synchronous motor which reduces the back electromotive force by reducing the number of turns of a part of stators without the need of flux weakening and speed extension in the prior art is not suitable for being used on an electric automobile.

In order to achieve the purpose, the technical scheme of the change-over switch of the permanent magnet synchronous motor is as follows: the change-over switch of the permanent magnet synchronous motor comprises: the conductive sliding blocks are arranged at intervals, each group of conductive sliding blocks comprises three-phase sliding blocks arranged at intervals so as to respectively correspond to three phases of the stator winding, each conductive sliding block is respectively used for being in conductive connection with windings with different turns in the stator winding, and an insulating sliding block is arranged between every two adjacent groups of conductive sliding blocks so that the insulating sliding blocks and the conductive sliding blocks form a closed annular structure; the carbon brush can rotate around the center of the annular structure so as to be in conductive contact with the conductive sliding block successively; and the driving mechanism is in transmission connection with the carbon brushes and is provided with a controller which can be used for driving the carbon brushes to rotate according to the rotating speed of the permanent magnet synchronous motor so that the carbon brushes are in conductive contact with each group of conductive sliding blocks successively.

The invention has the beneficial effects that: according to the change-over switch of the permanent magnet synchronous motor, at least two groups of conductive sliding blocks are arranged at intervals, under the condition that the circumferential size of the conductive sliding blocks is smaller, the number of the conductive sliding blocks is larger, the number of the segmented segments in the stator winding is furthest expanded according to the structure of the stator winding of the permanent magnet synchronous motor, the number of corresponding turns of the stator winding connected into the motor is adjusted according to the rotating speed of the motor, the field weakening and speed expansion are not needed, the motor can have higher output efficiency in a high-speed interval, and the rotating speed adjusting precision and the stable output power are realized in the rotating speed adjusting process.

Furthermore, the change-over switch of the permanent magnet synchronous motor also comprises an annular shell, the annular shell is used for being arranged on a rear end cover of the permanent magnet synchronous motor, and the conductive sliding block and the insulating sliding block are both fixed on the annular shell. The annular shell structure is arranged, so that the conductive sliding block and the insulating sliding block can be conveniently installed and positioned.

Furthermore, the driving mechanism takes the rear end cover of the permanent magnet synchronous motor as an installation basis and is arranged corresponding to the central position of the annular structure. The driving mechanism is positioned on the rear end cover of the permanent magnet synchronous motor, so that the driving mechanism is convenient to fixedly install, and the driving mechanism is arranged corresponding to the central position of the annular structure and is convenient to be connected with the carbon brush in a transmission manner.

Further, the maximum number of sets N of the conductive sliders that can be set is N × (Q/3), where N is the number of series turns of each winding element in the stator winding and Q is the number of slots of the stator winding. Under the condition that the number N of the series turns and the number Q of the slots of each winding element in a stator winding of the permanent magnet synchronous motor are determined, the maximum group number N of the conductive sliding block, namely the maximum subsection number which the sectional winding can have can be calculated so as to determine the maximum adjusting precision which can be achieved by the rotating speed of the permanent magnet synchronous motor, and the output power of the motor in the rotating speed adjusting process can be enabled to be the most stable.

Further, the distance between the conductive slider and the insulating slider and the center of the annular structure is equal. The distance between the insulating slide block and the conductive slide block is equal to the distance between the insulating slide block and the conductive slide block and the center of the annular structure, so that the insulating slide block can play a transition switching role in the rotating switching process of the carbon brush between the adjacent conductive slide blocks, and the carbon brush is prevented from being stuck.

Furthermore, the insulating sliding blocks positioned between the two adjacent groups of conductive sliding blocks are of an integrated structure, and the number of the groups of the insulating sliding blocks is equal to that of the groups of the conductive sliding blocks. The insulating slider of integral type structure simple structure, the processing of being convenient for.

Further, the three-phase slider is arranged along a line parallel to a central axis of the ring structure. The structure arrangement enables the three-phase sliding block to be simple in structure and convenient to arrange.

Furthermore, the central angle corresponding to the conductive slider is equal to the central angle corresponding to the contact surface of the carbon brush and the annular structure. The central angle corresponding to the conductive sliding block is equal to the central angle corresponding to the contact surface of the carbon brush and the annular structure, so that the carbon brush is exactly matched and contacted with the three-phase sliding block in the circumferential direction.

Furthermore, the conductive sliding block comprises a high-position conductive sliding block which is in contact fit with the carbon brush when the permanent magnet synchronous motor is at the lowest speed, the high-position conductive sliding block is used for connecting the maximum number of turns in the stator winding, and the low-position conductive sliding block which is in contact fit with the carbon brush when the permanent magnet synchronous motor is at the highest speed is used for connecting the minimum number of turns in the stator winding and is adjacent to the high-position conductive sliding block, and a limiting blocking piece is arranged between the two conductive sliding blocks so as to limit the direct switching of the carbon brush between the two conductive sliding blocks. The breakdown of components of the permanent magnet synchronous motor due to instantaneous back electromotive force surge in a stator winding caused by switching the carbon brush misoperation from the low-position conductive sliding block to the high-position conductive sliding block is avoided.

In order to achieve the purpose, the technical scheme of the permanent magnet synchronous motor is as follows: permanent magnet synchronous machine, including stator winding and motor casing, still include change over switch to the coil turn that the switching inserts in the stator winding, change over switch includes: the conductive sliding blocks are arranged at intervals, each group of conductive sliding blocks comprises three-phase sliding blocks arranged at intervals so as to respectively correspond to three phases of the stator winding, each conductive sliding block is respectively used for being in conductive connection with windings with different turns in the stator winding, and an insulating sliding block is arranged between every two adjacent groups of conductive sliding blocks so that the insulating sliding blocks and the conductive sliding blocks form a closed annular structure; the carbon brush can rotate around the center of the annular structure so as to be in conductive contact with the conductive sliding block successively; and the driving mechanism is in transmission connection with the carbon brushes and is provided with a controller which can be used for driving the carbon brushes to rotate according to the rotating speed of the permanent magnet synchronous motor so that the carbon brushes are in conductive contact with each group of conductive sliding blocks successively.

The invention has the beneficial effects that: in the permanent magnet synchronous motor, at least two groups of conducting slide blocks of the change-over switch are arranged at intervals, under the condition that the peripheral size of the conducting slide blocks is smaller, the number of the segmented sections in the stator winding can be enlarged, so that the conducting slide blocks have more number, the number of the segmented sections in the stator winding is enlarged to the maximum extent according to the structure of the stator winding of the permanent magnet synchronous motor, the corresponding number of turns of the stator winding connected into the motor is adjusted according to the rotating speed of the motor, the flux weakening speed expansion is not needed, the motor can have higher output efficiency in a high-speed interval, and the rotating speed adjusting precision and the more stable output power are realized in the rotating speed adjusting process; the radial size of the annular structure does not need to be enlarged, so that the permanent magnet synchronous motor can be used on an electric automobile.

Furthermore, the change-over switch of the permanent magnet synchronous motor also comprises an annular shell, the annular shell is used for being arranged on a rear end cover of the permanent magnet synchronous motor, and the conductive sliding block and the insulating sliding block are both fixed on the annular shell. The annular shell structure is arranged, so that the conductive sliding block and the insulating sliding block can be conveniently installed and positioned.

Furthermore, the driving mechanism takes the rear end cover of the permanent magnet synchronous motor as an installation basis and is arranged corresponding to the central position of the annular structure. The driving mechanism is positioned on the rear end cover of the permanent magnet synchronous motor, so that the driving mechanism is convenient to fixedly install, and the driving mechanism is arranged corresponding to the central position of the annular structure and is convenient to be connected with the carbon brush in a transmission manner.

Further, the maximum number of sets N of the conductive sliders that can be set is N × (Q/3), where N is the number of series turns of each winding element in the stator winding and Q is the number of slots of the stator winding. Under the condition that the number N of the series turns and the number Q of the slots of each winding element in a stator winding of the permanent magnet synchronous motor are determined, the maximum group number N of the conductive sliding block, namely the maximum subsection number which the sectional winding can have can be calculated so as to determine the maximum adjusting precision which can be achieved by the rotating speed of the permanent magnet synchronous motor, and the output power of the motor in the rotating speed adjusting process can be enabled to be the most stable.

Further, the distance between the conductive slider and the insulating slider and the center of the annular structure is equal. The distance between the insulating slide block and the conductive slide block is equal to the distance between the insulating slide block and the conductive slide block and the center of the annular structure, so that the insulating slide block can play a transition switching role in the rotating switching process of the carbon brush between the adjacent conductive slide blocks, and the carbon brush is prevented from being stuck.

Furthermore, the insulating sliding blocks positioned between the two adjacent groups of conductive sliding blocks are of an integrated structure, and the number of the groups of the insulating sliding blocks is equal to that of the groups of the conductive sliding blocks. The insulating slider of integral type structure simple structure, the processing of being convenient for.

Further, the three-phase slider is arranged along a line parallel to a central axis of the ring structure. The structure arrangement enables the three-phase sliding block to be simple in structure and convenient to arrange.

Furthermore, the central angle corresponding to the conductive slider is equal to the central angle corresponding to the contact surface of the carbon brush and the annular structure. The central angle corresponding to the conductive sliding block is equal to the central angle corresponding to the contact surface of the carbon brush and the annular structure, so that the carbon brush is exactly matched and contacted with the three-phase sliding block in the circumferential direction.

Furthermore, the conductive sliding block comprises a high-position conductive sliding block which is in contact fit with the carbon brush when the permanent magnet synchronous motor is at the lowest speed, the high-position conductive sliding block is used for connecting the maximum number of turns in the stator winding, and the low-position conductive sliding block which is in contact fit with the carbon brush when the permanent magnet synchronous motor is at the highest speed is used for connecting the minimum number of turns in the stator winding and is adjacent to the high-position conductive sliding block, and a limiting blocking piece is arranged between the two conductive sliding blocks so as to limit the direct switching of the carbon brush between the two conductive sliding blocks. The breakdown of components of the permanent magnet synchronous motor due to instantaneous back electromotive force surge in a stator winding caused by switching the carbon brush misoperation from the low-position conductive sliding block to the high-position conductive sliding block is avoided.

Drawings

Fig. 1 is a schematic structural diagram of a permanent magnet synchronous motor according to an embodiment of the present invention;

fig. 2 is a left side view of the permanent magnet synchronous machine of fig. 1;

fig. 3 is a schematic diagram of a circuit connection structure of a stator winding and a carbon brush in the permanent magnet synchronous motor in fig. 1;

FIG. 4 is a schematic structural diagram of the diverter switch of FIG. 1;

in the figure: the motor comprises a motor shell 1, a stator winding 2, a three-phase incoming line interface 3, a front end cover 4, a rear end cover 5, a change-over switch 6, a ring-shaped shell 7, a conductive sliding block 8, a connecting terminal 9, a phase A sliding block 10, a phase B sliding block 11, a phase C sliding block 12, an insulating sliding block 13, a carbon brush 14, a stepping motor 15, a high-position conductive sliding block 16, a low-position conductive sliding block 17 and a limit stop 18.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

The specific embodiment of the permanent magnet synchronous motor of the invention comprises the following steps:

as shown in fig. 1 to 2, the permanent magnet synchronous motor includes a motor housing 1, a stator winding 2 located in the motor housing 1, and a three-phase incoming line interface 3 disposed on an outer circumferential surface of the motor housing 1.

As shown in fig. 1 and 2, the motor housing 1 includes a rear end cover 5 and a front end cover 4 for penetrating through an output shaft of the motor, and the front end cover 4 and the rear end cover 5 are both circular and are arranged coaxially with the output shaft of the permanent magnet synchronous motor. The permanent magnet synchronous motor further comprises a change-over switch 6 arranged on the rear end cover 5, the change-over switch 6 comprises an annular shell 7, the annular shell 7 has insulating performance, and the annular shell 7 is fixed on the rear end cover 5 and is coaxially arranged with an output shaft of the motor.

As shown in fig. 1, 2 and 4, the change-over switch 6 further includes conductive sliders 8 fixed on the inner side wall of the annular housing 7 and arranged at intervals along the circumferential direction of the annular housing 7, the conductive sliders 8 are provided with 15 groups and uniformly arranged along the circumferential direction of the annular housing 7, and a connection terminal 9 is arranged on the outer side wall of the annular housing 7 corresponding to each group of conductive sliders 8.

Each set of conductive sliders 8 comprises three-phase sliders arranged at intervals, namely an a-phase slider 10, a B-phase slider 11 and a C-phase slider 12, as shown in fig. 4, the three-phase sliders are arranged at intervals along a straight line parallel to the central axis of the annular shell 7 and are electrically connected with three phases in corresponding sections of windings through phase terminals and phase connector terminals on the connecting terminals 9, so that 15 positions to be connected outside the motor shell 1 are formed in segmented winding lines, and as shown in fig. 3, the three-phase sliders arranged at intervals along the direction parallel to the central axis of the annular shell are simple in structure and convenient to process and assemble. Of course, in other embodiments, the three-phase sliding blocks can also be arranged at intervals along the direction which is arranged at an acute angle with the central axis of the annular shell.

As shown in fig. 4, an insulating slider 13 is disposed between two adjacent conductive sliders 8, and the insulating slider 13 is fixed on the annular housing 7, so that the insulating slider and the conductive slider 8 enclose a closed annular structure. Only one set of insulating sliders 13 is arranged between two adjacent sets of conductive sliders 8, so that the number of sets of insulating sliders 13 is equal to the number of sets of conductive sliders 8. In this embodiment, insulating slider 13 formula structure as an organic whole to insulating slider 13's processing preparation, in other embodiments, insulating slider also can split type setting, and a set of insulating slider includes three slider promptly, with respectively with the three-phase slider in the electrically conductive slider in arranging side by side in week.

The change-over switch 6 further comprises a carbon brush 14 rotating around the center of the annular structure, and the carbon brush 14 is located inside the annular shell 7 and elastically pressed against the annular structure, so that the structure of the change-over switch 6 is more compact. In other embodiments, the conductive slider and the insulating slider may also be fixed to the outer side wall of the annular housing, the connection terminal is fixed to the inner side wall, and the carbon brush is located outside the annular housing and elastically pressed against the conductive slider or the insulating slider.

In the embodiment, as shown in fig. 1 and 4, the carbon brush 14 is provided with a driving mechanism, specifically, a stepping motor 15, the stepping motor 15 is powered by an external power source of the permanent magnet synchronous motor, and the stepping motor 15 is fixed at a central position of the rear end cover 5 so as to be in transmission connection with the carbon brush 14, and can drive the carbon brush 14 to rotate around the center of the ring structure, so that the carbon brush 14 is only in contact with one set of conductive sliders 8 at any determined position, so that A, B and the C three-phase winding are in star connection, and the carbon brush 14 forms a star connection neutral point of the three-phase winding, as shown in fig. 3.

In this embodiment, the driving mechanism is the stepping motor 15, which facilitates control of the rotation angle of the carbon brush 14. In other embodiments, the drive mechanism may also be a servo motor or a hydraulic control device.

In this embodiment, the driving mechanism is provided with a controller, which can control the action of the stepping motor 15 according to the rotation speed of the motor, so as to drive the carbon brush 14 to rotate by a corresponding angle to be in conductive contact with the corresponding conductive slider 8.

As shown in fig. 1, 3 and 4, in this embodiment, when the motor is running at a low speed, the carbon brush 14 is connected to a position S15 in the stator winding 2, where the carbon brush 14 is correspondingly connected to the high-position conductive slider 16 with the largest number of turns of the stator winding 2, and when the motor speed exceeds 6000r/min, the controller controls the stepper motor 15 to drive the carbon brush 14 to rotate 24 ° counterclockwise, so that the carbon brush 14 is connected to a position S14, a part of the number of turns of the stator winding is cut off, the flux linkage in the stator winding 2 is reduced, and the back electromotive force in the stator winding 2 is reduced; after that, every time the rotating speed of the motor is increased by 500r/min, the carbon brush 14 rotates 24 degrees anticlockwise, the number of turns of the stator winding of 1/15 is cut off, the magnetic linkage in the stator winding 2 is reduced, and every time the rotating speed of the motor is reduced by 500r/min, the carbon brush 14 rotates 24 degrees clockwise, the number of turns of the stator winding of 1/15 is increased, the magnetic linkage in the stator winding 2 is improved to improve the counter electromotive force in the stator winding 2, and the constant power output of the motor is ensured. When the rotating speed of the motor reaches the highest speed of 13000r/min, the carbon brush 14 is connected at the position of S1, the carbon brush 14 is correspondingly connected at the position of S1 on the low-level conductive sliding block 17 with the least number of turns of the stator winding 2, the number of turns of the stator winding connected with the motor is the least, but the back electromotive force value is consistent with that of the motor at the low speed, so that the motor does not need flux weakening and speed expansion in the whole speed adjusting range.

In this embodiment, as shown in fig. 1 and 4, the low-position conductive slider 17 and the high-position conductive slider 16 are arranged on the annular housing 7 adjacently and at intervals, and the insulating slider 13 between the low-position conductive slider 17 and the high-position conductive slider 16 is provided with a limit stopper 18 to limit the carbon brush 14 to switch between the high-position conductive slider 16 and the low-position conductive slider 17, so as to avoid that the instantaneous back electromotive force on the stator winding 2 increases suddenly to break down components in the permanent magnet synchronous motor due to the false operation of the carbon brush 14 switching from the low-position conductive slider 17 to the high-position conductive slider 16.

In other embodiments, the insulating slider between the low-position conductive slider and the high-position conductive slider may not be provided with a limit stop, and since the carbon brush connecting arm is arranged between the stepping motor and the carbon brush, the limit stop may be arranged on the rear end cover of the motor housing to limit the carbon brush connecting arm from being switched from the low-position conductive slider to the high-position conductive slider; or in other embodiments, the limit stop may not be provided, and the controller controls the circumferential movement of the carbon brush, so that the controller can only drive the carbon brush to rotate clockwise when the rotation speed of the motor is at a high speed and the carbon brush is in conductive contact with the low-position conductive slider.

In addition, the carbon brush 14 can be switched between other adjacent conductive sliders 8 except the high-position conductive slider 16 and the low-position conductive slider 17 according to the gradual change of the rotating speed of the motor, so that the counter electromotive force in the motor can be adjusted according to the rotating speed requirement of the motor, the output efficiency of the high-speed operation region of the motor is improved, and the constant power output of the motor is kept.

In this embodiment, the conductive sliders on the switch 6 are provided with 15 groups to achieve an even division of the stator winding 2 into 15 segments. In other embodiments, according to the requirement of the adjustment precision of the motor rotation speed, the number of groups of the conductive sliding blocks on the change-over switch can be set to any number of groups between 2 and 15, the more the number of groups of the conductive sliding blocks is set, the higher the adjustment precision of the motor rotation speed is, and the more stable the output power of the motor is in the process of adjusting the motor rotation speed.

The maximum number of the sections which can be arranged on the stator winding of the permanent magnet synchronous motor is n, namely the maximum number of the groups of the conductive sliding blocks which can be arranged on the change-over switch is also n, the n groups of the conductive sliding blocks are respectively in conductive connection with the n sections of the windings with different turns in the stator winding, so that an S1 position, an S2 position and an S3 position … … Sn position which can be in conductive connection with the carbon brush are formed in the stator winding circuit. The maximum number of segments N that can be provided for the stator winding, or the maximum number of groups N of electrically conductive sliders that can be provided in the electric machine, is determined by the number of series turns N and the number of slots Q of each winding element in the stator winding, where the maximum number of segments/maximum number of groups N is N × (Q/3). In the permanent magnet synchronous motor according to the present embodiment, the number N of series turns of each winding element in the sectional winding is 5, and the number Q of slots is 48, so that the maximum number of sections that can be set in the sectional winding, that is, the maximum number N of groups of conductive sliders that can be set is 80; or in other embodiments, the number of serial turns N of each winding element in the segmented winding is 10, the number Q of motor slots is 42, and the maximum number of segments that the segmented winding can be set, that is, the maximum number N of groups of conductive sliders that can be set is 140. Therefore, in order to enable the motor to have the highest rotating speed adjusting precision, the number of the segmented segments of the stator winding, namely the number of the groups of the sliding blocks, is equal to the product of the number of the serial turns of each winding element in the stator winding and the number of each phase of slots only according to the number N of the serial turns of each winding element in the stator winding and the number Q of the slots.

In other embodiments, the number of the conductive sliding block groups on the change-over switch can be set to any number between 15 and 80, when the number of the conductive sliding block groups is set to 80, the rotating speed of the motor can reach the maximum adjusting precision, the flux weakening and speed expansion are not needed, and the output power of the motor in the speed adjusting process can be kept to be most stable.

In the permanent magnet synchronous motor, a relay is not required to be additionally arranged, the purpose of reducing the counter electromotive force in the stator winding can be realized by adopting a method of reducing the number of turns of part of the stator winding by arranging a change-over switch, and the number of the segmented segments of the stator winding can be enlarged under the limitation of the stator winding structure of the permanent magnet synchronous motor, so that the motor has higher output efficiency in a high-speed interval and has higher rotating speed adjusting precision and more stable output power in the rotating speed adjusting process; and the change-over switch has simple structure, no noise in the speed regulation process of the motor, and convenient replacement after the carbon brush is worn, so that the permanent magnet synchronous motor can be used on the electric automobile. As shown in fig. 1 and 4, in order to ensure that the carbon brush 14 only contacts one set of conductive sliders 8 at any determined position to avoid the phase-to-phase short circuit of the stator winding 2 and cause the motor to malfunction, in the embodiment, the central angle of the contact surface of the carbon brush 14 with the annular structure is smaller than that of the insulating slider 13, specifically, the central angle of the contact surface of the carbon brush 14 with the annular structure is 10 °, and the central angle of the corresponding insulating slider 13 is 14 °.

The corresponding central angle of the conductive slider 8 is also equal to the central angle of the carbon brush 14 corresponding to the contact surface of the annular structure, that is, the central angle of the conductive slider 8 is 10 °, so that the contact surface of the carbon brush 14 and the annular structure is exactly matched and contacted with the three-phase slider of the conductive slider 8 in the circumferential direction.

In other embodiments, the central angle of the contact surface of the carbon brush and the annular structure can also be equal to the central angle of the insulating sliding block, and the structural arrangement can also ensure that the carbon brush is only contacted with one group of conductive sliding blocks at any determined position; or in other embodiments, under the condition that the central angle corresponding to the contact surface of the carbon brush and the annular structure is smaller than or equal to the central angle corresponding to the insulating slider, the size of the central angle corresponding to the conductive slider does not need to be limited, and the requirement that the carbon brush can be in conductive contact with the three-phase slider in the conductive slider in the rotating process is met.

In this embodiment, the length of the contact surface of the carbon brush 14 with the annular structure in the central axis direction of the annular structure is equal to the sum of the length of the three-phase slider in the central axis direction of the annular structure and the gaps of the two adjacent sliders in the central axis direction of the annular structure, so that the contact surface of the carbon brush 14 with the annular structure in the central axis direction of the annular structure can completely cover the inner surface of the three-phase slider. In other embodiments, the length of the contact surface of the carbon brush with the annular structure in the central axis direction of the annular structure may not be limited as long as the contact surface of the carbon brush with the annular structure can contact the three-phase slider of the conductive slider.

In this embodiment, the distances between the conductive sliding block 8 and the insulating sliding block 13 and the center of the annular structure are equal, so that the insulating sliding block 13 can perform a transition switching function in the process that the carbon brush 14 rotates between the adjacent conductive sliding blocks, and the carbon brush 14 is prevented from being stuck. In other embodiments, the distance from the insulating sliding block to the center of the ring structure may be greater than or less than the distance from the conductive sliding block to the center of the ring structure, and the arc between the insulating sliding block and the conductive sliding block is smoothly transited, so that the carbon brush can smoothly transit in rotation between the conductive sliding block and the insulating sliding block.

In this embodiment, the change-over switch is arranged on the rear end cover of the motor shell, so that the change-over switch and the motor shell are assembled into an integrated structure, and the whole motor is convenient to assemble and transport. In other embodiments, the diverter switch may be arranged separately from the motor housing, i.e., a base for supporting the diverter switch is additionally provided on the diverter switch, and the connection terminals on the diverter switch are connected to the corresponding segments of the segmented winding by wires.

In this embodiment, change over switch includes annular housing for set up on the rear end of motor covers, and electrically conductive slider, insulating slider and binding post are all fixed on annular housing, are convenient for electrically conductive slider, insulating slider and binding post's installation and location. In other embodiments, the annular shell can also be arranged on the outer peripheral surface of the motor shell, or the annular shell is positioned on the rear end cover of the motor and is arranged with the insulating slide block into an integral structure; or in other embodiments, the annular shell is not arranged in the change-over switch, the conductive sliding block is connected with the insulating sliding block through the insulating connecting piece, the conductive sliding block is electrically connected with the wiring terminal through the connecting piece, the structures are fixed on the rear end cover of the motor shell through the insulating sliding block, and the structure can also facilitate the installation and the positioning of the conductive sliding block, the insulating sliding block and the wiring terminal.

In this embodiment, the annular shell is arranged coaxially with the output shaft of the permanent magnet synchronous motor, so that the length of the connecting wire between each group of conductive sliding blocks and the corresponding segmented winding can be reduced, and the harness arrangement is facilitated. In other embodiments, the annular housing and the output shaft of the permanent magnet synchronous motor can be arranged in different shafts.

In this embodiment, actuating mechanism is fixed on the rear end cover, and corresponds the central point with annular structure and put the setting, and the fixed mounting of actuating mechanism is convenient for, and the actuating mechanism of being convenient for is connected with the transmission of carbon brush moreover. In other embodiments, the driving mechanism may be separately disposed from the motor housing, and the driving mechanism is disposed corresponding to a central position of the annular structure.

The invention relates to a specific embodiment of a change-over switch of a permanent magnet synchronous motor, which comprises the following steps:

the specific structure of the change-over switch of the permanent magnet synchronous motor is the same as that of the change-over switch in the specific embodiment of the permanent magnet synchronous motor, and the detailed description is omitted here.