阅读说明：本技术 控制装置、电动压缩机及控制方法 (Control device, electric compressor, and control method ) 是由 渡边恭平 鹰繁贵之 于 2020-03-11 设计创作，主要内容包括：本发明的一方式为控制装置,其具备：电气检测部,检测有关设置于直流电源与逆变器的开关元件之间的主电容器的电气物理量；及保护控制部,根据所述电气物理量的变化,控制所述逆变器的开关元件,以防止电流流向所述主电容器。(One aspect of the present invention is a control device including: an electrical detection unit that detects an electrical physical quantity related to a main capacitor provided between a direct-current power supply and a switching element of an inverter; and a protection control unit that controls the switching element of the inverter so as to prevent a current from flowing to the main capacitor in accordance with a change in the electrical physical quantity.)

1. A control device is provided with:

an electrical detection unit that detects an electrical physical quantity related to a main capacitor provided between a direct-current power supply and a switching element of an inverter; and

and a protection control unit that controls the switching element of the inverter so as to prevent a current from flowing to the main capacitor in accordance with a change in the electrical physical quantity.

2. The control device according to claim 1,

when an absolute value of a slope of a change in the electrical physical quantity is greater than a predetermined value, the protection control portion controls the switching element of the inverter to prevent a current from flowing to the main capacitor.

3. The control device according to claim 1 or 2,

the protection control unit controls the switching element of the inverter to prevent a current from flowing to the main capacitor when the value of the electrical physical quantity satisfies a criterion of magnitude and an absolute value of a slope of a change of the electrical physical quantity is greater than a predetermined value.

4. The control device according to any one of claims 1 to 3, further comprising:

and a motor stop control unit configured to turn off all the switching elements of the inverter when a predetermined time has elapsed in a state in which the switching elements of the inverter are controlled to prevent a current from flowing to the main capacitor.

5. The control device according to any one of claims 1 to 4,

the inverter is a driving circuit of the motor,

the main capacitor is connected to the dc power supply via a switch that is turned on and off by an external device.

6. An electric compressor is provided with:

a compressor;

a motor driving the compressor;

an inverter that drives the motor;

a main capacitor provided between a direct-current power supply and a switching element of the inverter;

an electrical detection unit that detects an electrical physical quantity related to the main capacitor; and

and a protection control unit that controls the switching elements of the inverter so as to prevent a current from flowing to the main capacitor in accordance with a change in the electrical physical quantity.

7. A control method for a control device, the control device including:

an electrical detection unit that detects an electrical physical quantity related to a main capacitor provided between a direct-current power supply and a switching element of an inverter; and

a protection control unit for controlling the switching elements of the inverter,

in the control device, the control device is provided with a control unit,

the protection control unit controls the switching element of the inverter so as to prevent a current from flowing to the main capacitor in accordance with a change in the electrical physical quantity.

Technical Field

The invention relates to a control device, an electric compressor and a control method.

The present application claims priority based on patent application No. 2019-047681 filed on japanese application No. 3, 14, 2019, and the contents of which are incorporated herein by reference.

Background

A vehicle electric compressor, which is an example of a vehicle device using a motor, is configured by a compressor that compresses a refrigerant, a motor that rotates the compressor, and an inverter that controls the motor. The inverter is equipped with a plurality of switching elements for converting a dc voltage into an ac voltage in order to cause an ac current to flow through a stator winding of the motor, a control device for detecting a current/voltage of each unit and controlling the switching elements based on the detected current/voltage, a main capacitor provided to suppress a surge voltage generated by the operation of the switching elements or smooth the dc voltage, and the like (patent document 1).

The electric compressor is installed in a narrow space of a vehicle, and therefore, is required to be downsized. In order to miniaturize the electric compressor, the main capacitor is also required to be miniaturized. Since the capacitance of the main capacitor is related to its size, the capacitance of the main capacitor is necessarily reduced when the main capacitor is miniaturized.

The electric compressor receives a high voltage supply from a high voltage battery mounted on the vehicle, and compresses a refrigerant by rotating a motor and the compressor by an inverter (fig. 8). Fig. 8 to 11 are simple circuit diagrams showing a configuration example of the electric compressor 100. The electric compressor 100 shown in fig. 8 includes a compressor 4, a motor 3 for rotating the compressor 4, and an inverter 200 for controlling the motor 3. The inverter 200 includes 6 switching elements 201 to 206 and a main capacitor 207. The main capacitor 207 is connected to the high-voltage battery 5 via a switch (contactor or the like) 6. Fig. 8 shows the flow of current at a certain timing when the motor is operating. Fig. 9 shows an example of the flow of current immediately after the inverter stops (when the shutter 6 is turned on). Fig. 10 shows an example of the flow of current immediately after the inverter stops (when the shutter 6 is "off"). Fig. 11 shows an example of the flow of current immediately after the inverter stops.

When the switching elements are both in the "off" state (inverter stop state) during the operation of the electric compressor, the motor continues to rotate although the time is short due to the inertia of the compressor and the motor itself, and the current that has previously flowed through the motor or the induced voltage due to the rotation returns to the high-voltage battery through the inverter (fig. 9). This causes a voltage increase in the high-voltage battery.

On the other hand, a shutter is provided between the electric compressor and the high-voltage battery, and a system on the vehicle side controls the shutter. In the operation of the electric compressor, the shutter is opened by a command from the vehicle system, and the supply of electric power to the electric compressor may be interrupted. When the power supply from the high-voltage battery is lost, a voltage charged only in the main capacitor is supplied from the inverter to the motor. As described above, the main capacitor has a small capacity, and thus the voltage across it drops immediately. The control device of the electric compressor, for example, puts both the switching elements in the "off" state when the input voltage (i.e., the voltage across the main capacitor) is lower than the threshold value. As described above, when the shutter 6 is closed, the current flows into the high-voltage battery 5 (fig. 9), and when the shutter 6 is opened, the current flows into the main capacitor 207, and a sudden voltage increase in the voltage across the main capacitor occurs (fig. 10). If the increased voltage exceeds the withstand voltage of the switching element, the switching element may malfunction. As a method for preventing this, non-patent document 1 and the like have studied a method of appropriately controlling a switching element of an inverter in order to suppress a current from flowing into a main capacitor (fig. 11).

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-55582

Non-patent document

Non-patent document 1: qingmu, Zhongdao Xiongzai, Yidongchun, bird feather and nutv, method for suppressing voltage rise of dc capacitor at emergency stop of inverter, Nippon institute of Electrical and relation, conference of the 2012, A-72(2012)

Disclosure of Invention

Technical problem to be solved by the invention

In order to execute a method of appropriately controlling the switching elements of the inverter in order to suppress the current flowing into the main capacitor, it is preferable to recognize that the open state of the shutter is set on the side of the electric compressor. However, the above-described shutter is controlled by a system on the vehicle side. Therefore, there is a possibility that the information that the shutter is opened is not transmitted to the electric compressor. Therefore, in a configuration assuming that the information transmission is performed such that the shutter is opened, there is a case where a problem of controlling to suppress the current flowing in the main capacitor cannot be appropriately performed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device and a control method that can solve the above problems.

Means for solving the technical problem

According to the 1 st aspect of the present invention, a control device includes: an electrical detection unit that detects an electrical physical quantity related to a main capacitor provided between a direct-current power supply and a switching element of an inverter; and a protection control unit that controls the switching element of the inverter so as to prevent a current from flowing to the main capacitor in accordance with a change in the electrical physical quantity.

According to the 2 nd aspect of the present invention, the control device according to the 1 st aspect may be as follows: when an absolute value of a slope of a change in the electrical physical quantity is greater than a predetermined value, the protection control portion controls the switching element of the inverter to prevent a current from flowing to the main capacitor.

According to the 3 rd aspect of the present invention, the control device according to the 1 st or 2 nd aspect may be as follows: the protection control unit controls the switching element of the inverter to prevent a current from flowing to the main capacitor when the value of the electrical physical quantity satisfies a criterion of magnitude and an absolute value of a slope of a change of the electrical physical quantity is greater than a predetermined value.

According to the 4 th aspect of the present invention, the control device according to any one of the 1 st to 3 rd aspects may further include: and a motor stop control unit configured to turn off all the switching elements of the inverter when a predetermined time has elapsed in a state in which the switching elements of the inverter are controlled to prevent a current from flowing to the main capacitor.

According to the 5 th aspect of the present invention, the control device according to any one of the 1 st to 4 th aspects may be as follows: the inverter is a drive circuit of a motor, and the main capacitor is connected to the dc power supply via a switch that is turned on and off by an external device.

According to the 6 th aspect of the present invention, an electric compressor includes: a compressor; a motor driving the compressor; an inverter that drives the motor; a main capacitor provided between a direct-current power supply and a switching element of the inverter; an electrical detection unit that detects an electrical physical quantity related to the main capacitor; and a protection control unit that controls the switching element of the inverter so as to prevent a current from flowing to the main capacitor in accordance with a change in the electrical physical quantity.

According to the 7 th aspect of the present invention, in the control device including the electrical detection unit that detects the electrical physical quantity related to the main capacitor provided between the dc power supply and the switching element of the inverter and the protection control unit that controls the switching element of the inverter, the protection control unit controls the switching element of the inverter in accordance with the change in the electrical physical quantity so as to prevent the current from flowing to the main capacitor.

Effects of the invention

According to at least one of the above aspects, even when information that the shutter is opened is not transmitted, control for suppressing the current flowing in the main capacitor can be performed.

Drawings

Fig. 1 is a simplified circuit diagram for explaining a configuration example of an electric compressor according to an embodiment of the present invention.

Fig. 2 is a state transition diagram for explaining an operation example of the electric compressor 1 shown in fig. 1.

Fig. 3 is a diagram showing an example of the contents of the events E1 to E8 shown in fig. 2.

Fig. 4 is a graph showing an example of a measurement result of a change with time in the voltage across the main capacitor 27 shown in fig. 1.

Fig. 5 is a schematic diagram for explaining an operation example of another embodiment of the present invention.

Fig. 6 is a diagram showing another example of the contents of the events E1 to E8 shown in fig. 2.

Fig. 7 is a schematic block diagram showing a configuration of a computer according to at least one embodiment.

Fig. 8 is a schematic diagram showing an operation example of the electric compressor.

Fig. 9 is a schematic diagram showing an operation example of the electric compressor.

Fig. 10 is a schematic diagram showing an operation example of the electric compressor.

Fig. 11 is a schematic diagram showing an operation example of the electric compressor.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

< embodiment 1 >

Fig. 1 is a simple circuit diagram showing a configuration example of an electric compressor 1 according to embodiment 1 of the present invention. The electric compressor 1 shown in fig. 1 includes an inverter 2, a motor 3, and a compressor 4. The compressor 4 compresses a refrigerant. The motor 3 rotates the compressor 4. The inverter 2 is a drive circuit of the motor 3, and controls the motor 3.

The inverter 2 includes a plurality of switching elements 21 to 26 for converting a dc voltage into an ac voltage so that an ac current flows through a stator winding of the motor 3, and a plurality of flywheel diodes D1 to D6 connected in parallel to the respective switching elements 21 to 26. The inverter 2 further includes a control device 20, a main capacitor 27, a voltage detection unit 28 and a current detection unit 29 that detect the voltage or current of each unit, and the like. In this case, the main capacitor 27 suppresses a surge voltage generated by the operation of the switching elements 21 to 26, and smoothes a dc voltage of a dc power supply as a driving power supply of the motor 3. The voltage detection unit 28 detects the voltage across the main capacitor 27. The current detector 29 detects currents flowing between the plurality of switching elements 21 to 26 and the flywheel diodes D1 to D6 and the main capacitor 27. The control device 20 controls the switching elements 21 to 26 based on a command value of the rotation speed (rotation speed) of the motor 3 commanded from a system (external device) on the vehicle side and detection results of the voltage detection unit 28 and the current detection unit 29.

The control device 20 is configured to include, for example, a CPU (central processing unit), a storage device, an input/output device, and the like, and operates by the CPU executing a program stored in the storage device. The control device 20 includes a protection control unit 201, a motor stop control unit 202, and a rotation speed control unit 203 as a component of a function configured by a combination of hardware included in the control device 20 and software such as a program executed by a CPU.

The protection control unit 201 estimates whether or not the switch 6 is "off" based on a change in voltage or current (a change in an electrical physical quantity) detected by the voltage detection unit 28 or the current detection unit 29, and controls the switching elements 21 to 26 to prevent current from flowing to the main capacitor 27 when the estimation is "off". For example, when the absolute value of the slope of the change in voltage or current (change in the electrical physical quantity) detected by the voltage detection unit 28 or the current detection unit 29 is greater than a predetermined value, the protection control unit 201 estimates that the shutter 6 is "off" and controls the switching elements 21 to 26 so as to prevent the current from flowing to the main capacitor 27. The protection control unit 201 prevents a current such as a regenerative current of the motor 3 from flowing to the main capacitor 27 by turning all of the upper 3 switching elements 21 to 23 OFF and turning all of the lower 3 switching elements 24 to 26 ON. Alternatively, the protection control unit 201 prevents the regenerative current of the motor 3 from flowing to the main capacitor 27 by turning on all the upper 3 switching elements 21 to 23 and turning off all the lower 3 switching elements 24 to 26, for example.

When a predetermined time has elapsed while the protection control unit 201 controls the switching elements 21 to 26 to prevent the current from flowing to the main capacitor 27, the motor stop control unit 202 turns off all the switching elements 21 to 26. The fixed time is a time required for the rotation speed of the motor 3 rotated by inertia to be sufficiently reduced to be in a state where current does not flow to the main capacitor 27 (or a state where current hardly flows).

The rotation speed control unit 203 controls the rotation speed of the motor 3 by controlling the switching elements 21 to 26 based on a command value of the rotation speed of the motor 3 (hereinafter, referred to as a motor rotation speed command) issued from a system on the vehicle side.

In the example shown in fig. 1, the main capacitor 27 is connected to the high-voltage battery 5 as a dc power supply via a switch (contactor, electromagnetic switch, relay, etc.) 6. In the configuration shown in fig. 1, the voltage detection unit 28 and the current detection unit 29 are an example of an electrical detection unit that detects an electrical physical quantity related to the main capacitor 27 provided between the high-voltage battery 5 (dc power supply) and the inverter 2.

Next, an operation example of the electric compressor 1 shown in fig. 1 will be described with reference to fig. 1 to 3. Fig. 2 is a state transition diagram for explaining an operation example of the electric compressor 1 shown in fig. 1. Fig. 3 is a diagram showing an example of the contents of the events E1 to E8 shown in fig. 2.

As shown in fig. 2, the electric compressor 1 of the present embodiment operates in any of 4 states, namely, a motor stopped state S1, a motor operated state S2, a shutter state estimation state S3, and a main capacitor charge prevention state S4. The initial state is a motor stop state S1. The states S1-S4 transition according to the events E1-E8 shown in FIG. 3.

The motor stop state S1 is an operation state in which the rotation speed control unit 203 or the motor stop control unit 202 turns off all the switching elements 21 to 26 of the inverter 2. The motor operating state S2 is an operating state in which the rotational speed control unit 203 controls the switching elements 21 to 26 of the inverter 2 to be turned on/off in accordance with the motor rotational speed command to operate the motor 3. The shutter state estimation state S3 is an operation state in which the protection control unit 201 estimates whether the shutter 6 is "on" or "off" based on the detection result of the voltage detection unit 28 (or the current detection unit 29). The main capacitor charge prevention state S4 is an operation state in which the protection control section 201 controls the switching elements 21 to 26 to prevent a current from flowing to the main capacitor 27.

When the event E1 is generated in the motor stop state S1, the electric compressor 1 maintains the motor stop state S1. And, when the event E2 is generated in the motor stop state S1, the electric compressor 1 transits to the motor operation state S2. When the event E3 is generated in the motor operation state S2, the electric compressor 1 maintains the motor operation state S2. And, when the event E4 is generated in the motor running state S2, the electric compressor 1 transitions to the motor stop state S1. When the event E5 occurs in the motor operating state S2, the electric compressor 1 transitions to the shutter state estimation state S3. When the event E6 occurs in the shutter state estimation state S3, the state transitions to the main capacitor charge prevention state S4. And, when the event E7 is generated in the main capacitor charge prevention state S4, the transition is made to the motor stop state S1. When the event E8 occurs in the shutter state estimation state S3, the state transitions to the motor stop state S1.

The contents of the events E1 to E8 are shown in FIG. 3. Event E1 indicates whether the motor rotation speed command is 0rps (rotations per second), or whether the voltage across the main capacitor is less than a predetermined threshold Vx. Event E2 indicates that the motor rotation speed command is not 0rps, and the voltage across the main capacitor is equal to or higher than the threshold Vx. Event E3 indicates that the motor rotation speed command is not 0rps, and the voltage across the main capacitor is equal to or higher than the threshold Vx. Event E4 indicates that the motor speed command is 0 rps. Event E5 indicates that the voltage across the main capacitor is less than the threshold Vx. Event E6 indicates that the absolute value of the slope of the change in voltage across the main capacitor is greater than a prescribed threshold. Event E7 indicates that a certain time has elapsed. Event E8 means that the absolute value of the slope of the change in voltage across the main capacitor is less than a prescribed threshold.

For example, when a motor rotation speed command other than 0rps is input in the motor stop state S1 and the voltage across the main capacitor is equal to or higher than the threshold Vx (event E2 occurs), the rotation speed control unit 203 performs "on"/"off" control of the switching elements 21 to 26 of the inverter 2 in accordance with the motor rotation speed command to operate the motor 3 (motor operation state S2). When the motor rotation speed command becomes 0rps in the motor operating state S2 (event E4 occurs), the rotation speed control unit 203 turns "off" the switching elements 21 to 26 of the inverter 2 to stop the motor 3 (motor stop state S1).

When the voltage across the main capacitor becomes smaller than the threshold Vx in the motor operating state S2 (event E5 occurs), the protection control unit 201 estimates whether the switch 6 is "on" or "off" based on the voltage across the main capacitor detected by the voltage detection unit 28 (switch state estimation state S3). Here, an example in which the voltage across the main capacitor 27 changes with time after the shutter 6 is "off" is described with reference to fig. 4. Fig. 4 is a graph showing an example of a measurement result of a change with time in the voltage across the main capacitor 27 shown in fig. 1. In the example shown in fig. 4, the switch 6 is turned from "on" to "off" at time t1, the voltage across the main capacitor 27 becomes smaller than the threshold Vx at time t2, and the protection control unit 201 controls the switching elements 21 to 26 at time t3 so as to prevent the current from flowing to the main capacitor 27.

In the example shown in fig. 4, the electric compressor 1 is operated in the motor operation state s2 before the time t 2. When the end voltage of the main capacitor 27 becomes smaller than the threshold Vx at time t2, the electric compressor 1 transitions from the motor operation state S2 to the shutter state estimation state S3. When the state transitions to the shutter state estimation state S3, the protection control unit 201 calculates the absolute value of the slope of the change in the voltage across the main capacitor 27 (in this case, the voltage drop amount per unit time) for a certain period of time before the time t 2. At this time, the protection control unit 201 calculates the absolute value of the slope in the predetermined period shown in fig. 4, for example, a plurality of times (3 times in the example of fig. 4). When the absolute values of the slopes calculated a plurality of times are all greater than a predetermined threshold value (or greater than the predetermined threshold value 2 or more times), for example, the protection control unit 201 estimates that the shutter 6 is "off", and controls the switching elements 21 to 26 to prevent the current from flowing to the main capacitor 27 (main capacitor charge prevention state S4) in view of the occurrence of the event E6 (time t 3). After time t3, since no current flows in the main capacitor 27, the voltage across the main capacitor 27 is constant. After the transition to the main capacitor charge prevention state S4 at time t3, when a certain time has elapsed (event E7), the motor stop control unit 202 turns "off" all the switching elements 21 to 26 (motor stop state S1). As shown by the chain line in fig. 4, assuming that the switching elements 21 to 26 are all turned "off" at time t2, the voltage across the main capacitor 27 rises sharply.

In fig. 2, in the shutter state estimation state S3, when the absolute value of the slope of the change in the voltage across the main capacitor 27 for a certain period of time before the occurrence of the event E5 (in this case, the voltage drop amount per unit time) is smaller than the predetermined threshold value (corresponding to the event E8), the protection control unit 201 shifts the operating state to the motor stop state S1 without passing through the main capacitor charge prevention state S4, and the motor stop control unit 202 turns "off" all the switching elements 21 to 26 (the motor stop state S1). When the absolute value of the slope of the change in the voltage across the main capacitor 27 for a certain period before the occurrence of the event E5 is smaller than the predetermined threshold value, it is estimated that the switch 6 is not "off" and the voltage of the high-voltage battery 5 is in a state of decreasing. When the switch 6 is turned "on" and the high-voltage battery 5 is connected, even if the switching elements 21 to 26 are all turned "off", the regenerative current of the motor 3 flows into the high-voltage battery 5, and therefore the voltage across the main capacitor 27 does not increase rapidly. On the other hand, in the main capacitor charge prevention state S4, a short-circuit current caused by regenerative power generated by the motor 3 flows to a part of the switching elements 21 to 26, and therefore a relatively large load is imposed on a part of the switching elements 21 to 26. Therefore, when the event E8 occurs, the operating state of the electric compressor 1 is transitioned to the motor stop state S1 without going through the main capacitor charge prevention state S4.

In embodiment 1, the open/close state of the shutter 6 is determined by monitoring the change in the voltage across the main capacitor 27. When the shutter 6 is opened in the operation of the electric compressor 1, the electric compressor 1 continues the operation by the voltage charged to the main capacitor 27. The main capacitor 27 has a small capacity, and the voltage across it continues to decrease rapidly as shown in fig. 4. On the other hand, since the voltage of the high-voltage battery 5 also decreases due to the driving of the vehicle, the voltage across the main capacitor 27 may decrease. However, the speed of the decrease in the voltage of the high-voltage battery 5 caused by the driving of the vehicle is much slower than the speed of the rapid decrease in the voltage across the main capacitor 27 when the shutter 6 is opened. By using this difference, the electric compressor 1 can discriminate between a voltage drop in the closed state of the shutter 6 and a voltage drop in the open state of the shutter 6. With this characteristic, in embodiment 1, when the absolute value of the slope of the change in the voltage across the main capacitor is large and the voltage across the main capacitor is lower than the threshold Vx, it is determined that the shutter 6 is in the open state.

In embodiment 1, when it is determined that the shutter 6 is open, the switching elements 21 to 26 are controlled so as to suppress charging of the main capacitor 27 in a short time until the inertial operation of the motor 3 is stopped. Conversely, when the absolute value of the slope of the change in the voltage across the main capacitor is small and the voltage across the main capacitor is lower than the threshold Vx, it is determined that the voltage of the high-voltage battery 5 drops in a state where the shutter 6 remains closed.

In addition, the threshold value of the absolute value of the slope of the change in the voltage across the main capacitor can be determined experimentally in advance. When the voltage across the main capacitor exceeds the threshold Vx, it can be determined that the shutter 6 is closed.

According to embodiment 1, the open/close state of the shutter 6 can be estimated without receiving information on the shutter 6 from the vehicle side. Further, for example, the open/close state of the shutter 6 can be estimated without adding a component to an existing product.

< embodiment 2 >

Next, embodiment 2 of the present invention will be described with reference to fig. 5 and 6. Fig. 5 is a schematic diagram for explaining an operation example of embodiment 2. Fig. 6 is a graph showing an example of the contents of each event shown in fig. 2 in embodiment 2.

The electric compressor according to embodiment 2 has the same configuration as the electric compressor 1 according to embodiment 1 shown in fig. 1. The state transition diagram of the electric compressor according to embodiment 2 is the same as the state transition diagram of the electric compressor 1 according to embodiment 1 shown in fig. 2. However, the contents of the events E1 to E8 in the state transition diagram shown in fig. 2 are partially different between embodiment 1 and embodiment 2.

Fig. 5 schematically shows the time-dependent changes in the voltage across the main capacitor detected by the voltage detection unit 28 and the current detected by the current detection unit 29 when the switch 6 is switched from "on" to "off". When the shutter 6 is opened (at the time of "off") during the operation of the electric compressor 1, the voltage across the main capacitor decreases rapidly, but the current flowing between the switching elements 21 to 26 and the main capacitor 27 increases rapidly. The current flowing through the main capacitor 27 can be detected by a current detection unit 29 provided between the switching elements 21 to 26 and the main capacitor 27 when the shutter 6 is opened. In embodiment 2, this operation is used to estimate the open/closed state of the shutter 6 from the magnitude of the main capacitor current and the absolute value of the slope of the change in the main capacitor current, instead of the change in voltage in embodiment 1.

As shown in fig. 6, in embodiment 2, the contents of events E5, E6, and E8 shown in fig. 2 are changed as follows, compared with embodiment 1. That is, event E5 of embodiment 2 means that the current between the main capacitor and the switching element is greater than the threshold Ix. Event E6 of embodiment 2 is when the absolute value of the slope of the change in current between the main capacitor and the switching element is greater than a predetermined threshold. Event E8 in embodiment 2 is a case where the absolute value of the slope of the change in current between the main capacitor and the switching element is smaller than a predetermined threshold value.

According to embodiment 2, as in embodiment 1, the open/close state of the shutter 6 can be estimated without receiving information on the shutter 6 from the vehicle side. Further, the open/close state of the shutter 6 can be estimated without adding a component.

In embodiment 1 and embodiment 2, for example, the slope of the change in voltage or current may be periodically monitored without depending on the magnitude of the voltage or current and the result of comparison between the predetermined threshold values Vx or Ix, and it may be estimated that the shutter 6 is in the open state when the absolute value of the slope of the change exceeds the predetermined threshold value. In this case, in order to avoid erroneous estimation due to the influence of noise or the like, for example, it is preferable that the absolute value of the slope of the change is compared with a predetermined threshold value a plurality of times (for example, 3 times or more), and when a predetermined comparison result is obtained a plurality of times, it is estimated that the shutter 6 is in the open state.

As described above, the control device 20 according to each embodiment of the present invention includes the voltage detection unit 28 or the current detection unit 29 (electrical detection unit) that detects the voltage or the current (electrical physical quantity) of the main capacitor 27 provided between the high-voltage battery 5 (dc power supply) and the switching elements 21 to 26 of the inverter 2, and the protection control unit 201 that controls the switching elements 21 to 26 of the inverter 2 in accordance with the change in the voltage or the current (electrical physical quantity) to prevent the current from flowing to the main capacitor 27. According to this configuration, even when the information that the shutter 6 is opened is not transmitted to the electric compressor 1, it is possible to appropriately perform control for suppressing the current flowing into the main capacitor 27.

When the absolute value of the slope of the change in voltage or current (electrical physical quantity) is greater than a predetermined value, the protection control unit 201 controls the switching elements 21 to 26 of the inverter 2 so as to prevent the current from flowing to the main capacitor 27. When the value of the voltage or the current (the electrical physical quantity) satisfies the reference of the magnitude and the absolute value of the slope of the change in the voltage or the current (the electrical physical quantity) is larger than a predetermined value, the protection control unit 201 controls the switching elements 21 to 26 of the inverter 2 so as to prevent the current from flowing to the main capacitor 27. When a predetermined time has elapsed while the switching elements 21 to 26 of the inverter 2 are controlled to prevent the current from flowing to the main capacitor 27, the control device 20 turns off all the switching elements 21 to 26 of the inverter 2. The inverter 2 is a drive circuit of the motor, and the main capacitor 27 is connected to the high-voltage battery 5 (dc power supply) via the switch 6 that is turned on or off by an external device.

While the embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to the above embodiments, and design changes and the like are included within the scope not departing from the gist of the present invention.

< computer Structure >

Fig. 7 is a schematic block diagram showing a configuration of a computer according to at least one embodiment.

The computer 90 includes a processor 91, a main memory 92, a memory 93, and an interface 94.

The control device 20 is mounted on the computer 90. The operations of the processing units are stored in the memory 93 as programs. The processor 91 reads out the program from the memory 93 and expands the program in the main memory 92, and executes the above-described processing in accordance with the program. The processor 91 also secures a storage area corresponding to each storage unit in the main memory 92 according to the program.

The program may be a program for realizing a part for causing the computer 90 to function. For example, the program may be a program that functions in combination with another program stored in the memory or in combination with another program installed in another device. In another embodiment, the computer may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (general Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, a part or all of the functions realized by the processor may be realized by the integrated circuit.

Examples of the Memory 93 include an HDD (Hard Disk Drive), an SSD (Solid State Drive), a magnetic Disk, an optical magnetic Disk, a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital versatile Disc Read Only Memory), a semiconductor Memory, and the like. The memory 93 may be an internal medium directly connected to the bus of the computer 90, or may be an external medium connected to the computer 90 via the interface 94 or a communication line. When the program is transferred to the computer 90 via the communication line, the computer 90 that has received the transfer may expand the program in the main memory 92 and execute the processing described above. In at least one embodiment, the memory 93 is a non-transitory tangible storage medium.

Industrial applicability

According to the control device, even when information that the shutter is opened is not transmitted, it is possible to appropriately perform control for suppressing the current flowing into the main capacitor.

Description of the symbols

1-electric compressor, 2-inverter, 3-motor, 4-compressor, 5-high voltage battery, 6-shutter, 20-control device, 21-26-switching element, 27-main capacitor, 28-voltage detection part, 29-current detection part, 201-protection control part, 202-motor stop control part, 203-rotation speed control part.