JP2021197753A - Inverter device - Google Patents

Abstract

To solve a problem such that, in an inverter device that implements torque suppression control executed for protecting a motor from overheat, while when a motor is started without cooling, a torque suppression value of operation end is stored because the motor cannot be protected from overheat, when the previous torque suppression value stored at the time of operation end is low, torque of the motor is restricted.SOLUTION: A torque suppression value is calculated and control is adapted to be performed in accordance with downtime based on a previous torque suppression value at the time of operation end of an inverter, a temperature detection value, and downtime of the inverter or a motor using information on the downtime of the inverter or the motor.SELECTED DRAWING: Figure 1

Description

The present application relates to an inverter device.

The in-vehicle motor is used as a drive source for a vehicle or a drive source for a steering device, and is driven by an inverter device. This inverter device converts direct current into alternating current and drives the motor with a predetermined torque and frequency. Since the temperature of the switching element of the inverter that composes the inverter device fluctuates greatly depending on the usage condition of the vehicle, the inverter is cooled so as not to exceed the preset temperature, or the temperature of the inverter or the temperature of the motor is adjusted. Control is performed such as detecting by a temperature sensor, storing the detected temperature information in a storage device, and limiting the torque or switching frequency according to the temperature information.

In particular, in Patent Document 1, the control of the motor used in the electric power steering device is shown, and the stored temperature information is not reset by the engine stall, even if there is no power supply. Using a non-volatile storage means that can be stored, the detected temperature information is stored in the storage means after the engine is started and before the engine stalls with the ignition switch turned on. It has been proposed that when the motor is restarted, the temperature information detected by the temperature sensor is compared with the temperature information stored in the storage means, and control is performed using the high temperature information. There is.

Japanese Patent No. 4513367

In the control device shown in Patent Document 1, since the value used at the time of starting is the information at the higher temperature among the stored value and the value detected by the temperature sensor as the initial value, the high estimated temperature stored at the time of starting is used. The value may limit the motor output. In particular, if the stall state continues and the motor ends with a high temperature, the value memorized at the end will be used as it is at startup, so if the pause time is sufficiently long, that is, the ignition switch will be turned on. If the off state is long enough, the initial value is set using the higher temperature of the stored value and the value detected by the temperature sensor, even though the actual temperature detection value has dropped. , There is a problem that the motor output is limited.
Further, when the proposed technique is applied to the vehicle drive motor, there is a problem that the vehicle may not be able to start due to the suppression of the motor output (torque).

The present application discloses a technique for solving the above-mentioned problems, and an object of the present application is to provide an inverter device that controls according to the actual state of temperature change.

The inverter device disclosed in the present application is connected between a power supply and a motor, an inverter that converts the voltage of the power supply and outputs the output to the motor, a temperature detection unit that detects the temperature of the motor, and a suspension of the inverter or the motor. A pause time information providing device that provides time information, a storage device that stores the previous torque suppression value at the end of operation of the inverter, a command value calculation unit that outputs a torque command value, the temperature detection value, and the pause. It has a suppression value calculation unit that calculates the torque suppression value according to the time and the previous torque suppression value, and a minimum selection processing unit that sets the final torque command value based on the torque command value and the torque suppression value. However, it is characterized by being provided with a control device for controlling the switching operation of the inverter.

When the pause time is long and the coil temperature is low, the torque at startup can be increased by calculating using the pause time information.

It is a block diagram which shows the structure of the motor drive device of Embodiment 1. FIG. It is a block diagram which shows the structure of the control device of Embodiment 1. FIG. It is a block diagram which shows the structure of the control device of Embodiment 1. FIG. It is a block diagram which shows the structure of the suppression value calculation part of Embodiment 1. FIG. It is a timing diagram which shows the torque final command value of Embodiment 1. FIG. It is a timing diagram which shows the torque final command value of the comparative example 1. FIG. It is a flow diagram of the process in the start-up process part of Embodiment 1. FIG. It is a timing diagram which shows the torque final command value of Embodiment 1. FIG. It is a timing diagram which shows the torque final command value of the comparative example 2. FIG. It is a block diagram which shows the structure of the suppression value calculation part of Embodiment 2. It is a flow diagram of the process in the start-up process part of Embodiment 2. FIG. It is explanatory drawing which shows the relationship between the start value, the coil temperature detection value, and the start value.

Embodiment 1
FIG. 1 is a configuration diagram of a motor drive device according to the first embodiment. In the figure, the same reference numerals indicate the same or corresponding parts.
As shown in FIG. 1, the inverter device 1 is composed of an inverter 4 that converts direct current from a power source 2 into alternating current and inputs it to a motor 3, and a control device 5 that controls the inverter 4. In FIG. 1, the power supply 2 includes a high voltage power supply system 21 and a low voltage power supply system 22. The high voltage power supply system 21 supplies electric power to the motor 3 through the inverter 4. The low voltage power supply system 22 is configured to supply electric power to the control device 5 of the inverter device 1. A contactor 220 is provided between the low voltage power supply system 22 and the control device 5, and is configured to turn on / off the electric power.

The inverter 4 includes a first voltage conversion circuit 41 for converting electric power to the motor 3, a second voltage conversion circuit 42, and a third voltage conversion circuit 43, and the inverter 4 includes a first voltage conversion circuit 41 in front of the first voltage conversion circuit 41. A capacitor 44 and a voltage detection unit 45 for detecting the voltage of the capacitor 44 are provided.
The first voltage conversion circuit 41 is a first connection portion 41c between a first switching element 41a and a second switching element 41b connected in series, and a first switching element 41a and a second switching element 41b. It is composed of.

The second voltage conversion circuit 42 is a second connection portion 42c of a third switching element 42a and a fourth switching element 42b connected in series, and a third switching element 42a and a fourth switching element 42b. It is composed of.
The third voltage conversion circuit 43 is a third connection portion 43c between the fifth switching element 43a and the sixth switching element 43b connected in series, and the fifth switching element 43a and the sixth switching element 43b. It is composed of.

A diode is connected in parallel to each of the first switching element 41a to the sixth switching element 43b of the first voltage conversion circuit 41, the second voltage conversion circuit 42, and the third voltage conversion circuit 43.
The switching of the first voltage conversion circuit 41, the second voltage conversion circuit 42, and the third voltage conversion circuit 43 of the inverter 4 is controlled by the gate signals Gate41a, Gate41b, Gate42a, Gate42b, Gate43a, and Gate43b from the control device 5. Has been done.

The output of the inverter 4 is detected by the current detection unit 6. The current detection unit 6 is a third connection unit 41c of the first voltage conversion circuit 41 of the inverter 4, a second connection unit 42c of the second voltage conversion circuit 42, and a third voltage conversion circuit 43. The current value IU that flows between the connection portion 43c and the motor 3 and flows through the first voltage conversion circuit 41, the current value IV that flows through the second voltage conversion circuit 42, and the current value that flows through the third voltage conversion circuit 43. Detect IW.
The voltage value Vin detected by the voltage detection unit 45 and the current values IU, IV, and IW detected by the current detection unit 6 are input to the control device 5, respectively.

Further, the motor 3 is provided with a rotation position detection unit 7 that detects the rotation position θ of the motor 3, and a temperature detection unit 8 that detects the coil temperature of the motor 3 and the temperature of the oil that cools the motor 3. Information on θ, coil temperature, and oil temperature is provided to the control device 5.
Further, the inverter device 1 is provided with a pause time information providing device 9 that detects the pause time of the inverter device 1 and provides the pause time information to the control device 5.
Further, the control device 5 has a receiving unit 50 that receives the pause time information provided by the pause time information providing device 9, and receives the pause time information provided by the pause time information providing device 9 when the inverter device 1 is started. Use downtime information. In the following description, the pause time of the inverter device 1 is described as the pause time information, but the same control can be performed even if the pause time of the motor 3 is provided as the pause time information.

The control device 5 is a part of the inverter device 1, and the control device 5 has a voltage value Vin detected by the voltage detection unit 45 and a current value detected by the current detection unit 6 in order to control the motor 3. Switching element 41a of the first voltage conversion circuit 41, the second voltage conversion circuit 42, and the third voltage conversion circuit 43 based on the rotation speed ω calculated from the IU, IV, IW and the rotation position θ of the motor 3. , 41b, 42a, 42b, 43a, 43b are generated to generate gate signals Gate41a, Gate41b, Gate42a, Gate42b, Gate43a, Gate43b for on / off control (opening / closing operation) to control by PWM (Pulse Voltage Modulation) control, and a motor. Control the output of 3.

The control device 5 includes a processor 51 for on / off control of the first switching element 41a to the sixth switching element 43b. The processor 51 of the control device 5 may be composed of an analog electronic circuit such as a comparator, an operational amplifier, or a differential amplifier circuit, may be composed of a digital electronic circuit such as an arithmetic processing device, or may be composed of a digital electronic circuit and an analog. It may be composed of both electronic circuits.
That is, as shown in FIG. 2, an example of hardware is composed of a processor 51 and a storage device 52. Although the storage device is not shown, it includes a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. Further, the auxiliary storage device of the hard disk may be provided instead of the flash memory. The processor 51 executes the program input from the storage device 52.

In this case, a program is input from the auxiliary storage device to the processor 51 via the volatile storage device. Further, the processor 51 may output data such as a calculation result to the volatile storage device of the storage device 52, or may store the data in the auxiliary storage device via the volatile storage device.
Here, the storage device 52 is a device that stores data or values even if there is no electric power. When the inverter device 1 ends its operation, it stores the values in the state before the end, and there is no power supply during the pause time. Even in some cases, it remembers the information.

FIG. 3 is a block diagram showing a configuration of a control unit 500 provided in the control device 5 shown in the first embodiment.
The control unit 500 is a part of the control device 5. The control unit 500 uses the oil temperature detection value Tool detected from the temperature detection unit 8, the rotation speed ω calculated from the rotation position θ, the pause time information, and the torque command final value Tf to set the torque suppression value Tsave. Torque by selecting the smallest value among the suppression value calculation unit 501 that calculates and outputs, the command value calculation unit 502 that calculates and outputs the torque command value Tref, the torque command value Tref, and the torque suppression value Tsave. The minimum selection processing unit 503 with the command final value Tf, the torque command final value Tf, the voltage detection value Vin, the current detection values IU, IV, IW, and the rotation speed ω for motor control are used. It is composed of a motor control unit 504 that generates PWM signals Gate41a, Gate41b, Gate42a, Gate42b, Gate43a, and Gate43b that control the voltage conversion circuit 41 of 1, the second voltage conversion circuit 42, and the third voltage conversion circuit 43. ..

FIG. 4 is a block diagram showing the configuration of the suppression value calculation unit 501.
The suppression value calculation unit 501 includes a selection unit 501a for selecting a torque suppression rate coefficient Tr using an oil temperature value Tool and a rotation speed ω, and a torque suppression rate coefficient Tr for the purpose of expanding the motor output range. , The calculation unit 501b that calculates the torque change rate Te using the torque command final value Tf, the torque change rate Te, and the four-rule calculation unit 501c that performs the four-rule calculation Tt of the start value Tk calculated by the start processing unit 501g. , The limiting unit 501d that limits the four-rule calculation value Tt and outputs the torque suppression value Tsave in order to improve the control stability, the previous value calculation unit 501e that calculates the previous value Td of the torque command value Tref, and the storage device 52. The storage / reading unit 501f that stores the torque suppression value Tsave in the storage device 52 and performs the reading processing of the torque suppression value (referred to as the previous torque suppression value) Tsave 01 at the time of the previous processing stored in the storage device 52, and the reception unit 50 receives the torque suppression value Tsave. It is composed of a start processing unit 501g that calculates a start value Tk using the pause time information, the pre-torque suppression value Tsave01 stored in the storage device 52, and the previous value Td of the torque command value Tref.

Here, the timing diagram of FIG. 5 shows that the coil is protected from overheating by providing the start processing unit 501g and the storage / reading unit 501f. Here, the torque suppression value at the end is stored in the storage device 52, the previous torque suppression value Tsave01 stored in the storage device 52 at the time of startup is read out from the storage / reading unit 501f, and the operation is started after the pause period. This protects the coil from overheating. In the timing diagram of FIG. 5, the period Tq represents a period in which the torque is limited according to the torque suppression value.
On the other hand, FIG. 6 shows a timing diagram as Comparative Example 1 in the case where the storage device 52, the start processing unit 501g, and the storage / reading unit 501f are not provided. In the case of Comparative Example 1, when the stall state continues, since the storage device 52 is not provided and the value at the end is not stored, the torque suppression value is initially set at the start after the rest period. The coil may not be protected from overheating in the case of a short rest period because it is reset or reset.

Next, the processing in the activation processing unit 501g of the first embodiment will be described with reference to the flow chart of FIG.
In step S11, it is determined whether the state of the inverter device 1 is at the time of startup. When the state of the inverter device 1 is operating, in step S12, the previous value Td of the torque command value Tref is used as it is as the starting value Tk. In the case of startup, in step S13, the value obtained by multiplying the previous torque suppression value Tsave01 stored in the storage device 52 at the end and the pause time received by the receiving unit 50 by the coefficient α (= pause time ×). By outputting the value (= Tsave01 + pause time × α) obtained by adding α), the torque suppression value at the time of starting is increased.
Here, the timing diagram of FIG. 8 shows that the coil is protected from overheating even in the processing state when the pause time is long.

During the operation of the inverter device 1, the previous value Td of the torque suppression value Tsave is output as the start value Tk, and the minimum value is selected from the torque suppression value Tsave or the torque command value Tref to output the torque command final value Tf. Therefore, the motor 3 can be protected from overheating. That is, at the end of the inverter device 1, the storage device 52 stores the torque suppression value Tsave at the end. During the pause time of the inverter device 1, even if there is no electric power, it is stored as the previous torque suppression value Tsave 01 in the storage device 52.
When the inverter device 1 is started, the previous torque suppression value Tsave01 stored in the storage device 52 is read out, and the value obtained by multiplying the previous torque suppression value Tsave01 by the pause time and the coefficient (pause time × α) is added. Since the torque suppression value Tsave is output accordingly and the motor is controlled according to the torque suppression value Tsave, the torque suppression value Tsave is not reset at startup, and the value obtained by multiplying the pause time and the coefficient (pause time x α) is added. Therefore, even if the stall state continues, the torque of the motor 3 can be controlled without limitation.

On the other hand, FIG. 9 shows a timing diagram as Comparative Example 2 in which the output is limited due to the absence of the activation processing unit 501g even if the storage device 52 and the storage / reading unit 501f are provided. FIG. 9 shows a temperature detection value having a long pause time, although the coil can be protected from overheating because the value at the end can be stored and read out at the start when the pause time is short due to the mounting of the storage device 52. Even if the temperature drops sufficiently, the stored value at the end is read out and used as it is, so the torque is limited.

Embodiment 2
In the second embodiment, a part of the suppression value calculation unit 501 of the first embodiment is changed, and as shown in FIG. 10, the coil temperature detection value Tcoil of the motor 3 is input to the start processing unit 501g for calculation. It is configured to do. That is, FIG. 10 is a block diagram showing the configuration of the suppression value calculation unit 501. Here, the coil temperature detection value is input to the start processing unit 501 g, which is different from FIG.

Next, the processing in the activation processing unit 501g of the second embodiment will be described with reference to the flow chart of FIG.
In step S21, it is determined whether the state of the inverter device 1 is at the time of startup. When the state of the inverter device 1 is operating, in step S22, the previous value Td of the torque command value Tref is used as it is as the starting value Tk. When the state of the inverter device 1 is the start-up time, in step S23, it is determined whether or not the pause time is longer than the predetermined predetermined time.

When the pause time is longer than the specified time, in step S24, the value (= f (Tcoil)) of the coil temperature detection value Tcoil function received from the temperature detection unit 8 is output as the start value Tk. The "specified time" is the time from the overheated state until the inverter 4 or the motor 3 is saturated with the outside air temperature or the temperature of the oil that cools the motor 3, and is set in advance based on the actual measurement result. ..
FIG. 12 shows the relationship between the coil temperature detection value Tcoil and the start value Tk. When the pause time is sufficiently long, the coil temperature detection value Tcoil detected by the temperature detection unit 8 of the motor 3 is predicted to be the temperature of the hottest part in the motor 3, so that the higher the coil temperature, the more torque. Use a function or map that suppresses.

When the state of the inverter device 1 is at the start and the pause time is shorter than the specified time, it is received by the previous torque suppression value Tsave 01 and the receiving unit 50 stored in the storage device 52 at the end in step S24. By outputting a value (= Tsave01 + pause time x α) obtained by multiplying the pause time by the coefficient α (= pause time x α), control is performed without torque limitation of the motor 3 even if the stall state continues. Can be done.

The motor drive device of the embodiment is mounted on an electric vehicle or a hybrid vehicle, and is detected by a temperature detection unit provided in an inverter for driving a vehicle drive motor or an engine drive motor generator. It can also be applied in configurations that use values.
The temperature detection unit 8 of the embodiment may be the temperature of any part of the motor 3, the coil, the inverter device 1, or the motor drive device, and the temperature of two or more places may be used according to the temperature distribution state. It may be controlled.
The limiting portion 501d of the embodiment can be omitted in order to expand the range of the torque suppression value Tsave.

Similar control can be applied to a device including two or more inverter devices 1 or motors 3 according to the embodiment.
A system including a boost converter can be provided between the inverter device 1 and the power supply 2 of the embodiment.
The electric power of the control device 5 of the embodiment can be stepped down from the high voltage power supply system 21 to use the power source.
The pause time information of the embodiment can be detected from the state of the contactor or the state of change due to the pause of the inverter device such as the voltage value between the contactor and the control device.

Although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are applications of a particular embodiment. It is not limited to, but can be applied to embodiments alone or in various combinations.
Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

1 Inverter device, 2 power supply, 3 motor, 4 inverter, 5 control device,
6 current detection unit, 7 rotation position detection unit, 8 temperature detection unit, 9 pause time information providing device,
21 High voltage power supply system, 22 Low voltage power supply system, 41 First voltage conversion circuit,
42 Second voltage conversion circuit, 43 Third voltage conversion circuit, 50 Receiver,
51 processor, 52 storage device, 220 contactor, 501 suppression value calculation unit,
502 Command value calculation unit, 503 Minimum selection processing unit, 504 Motor control unit

Claims (5)

An inverter that is connected between the power supply and the motor and converts the voltage of the power supply and outputs it to the motor, a temperature detector that detects the temperature of the motor, and a pause time that provides information on the downtime of the inverter or the motor. The information providing device, the storage device that stores the previous torque suppression value at the end of the operation of the inverter, the command value calculation unit that outputs the torque command value, the temperature detection value of the temperature detection unit, the pause time, and the previous time. The inverter has a suppression value calculation unit that calculates a torque suppression value according to a torque suppression value, and a minimum selection processing unit that sets a final torque command value based on the torque command value and the torque suppression value. An inverter device characterized by being equipped with a control device that controls the switching operation of. The control device is characterized in that it adds a value obtained by multiplying the rest time by a preset coefficient to the previous torque suppression value read from the storage device, and performs an operation of the suppression value calculation unit. Item 1. The inverter device according to Item 1. The first or second aspect of the present invention, wherein when the pause time is longer than a preset predetermined time, the suppression value calculation unit is calculated according to the temperature detected by the temperature detection unit. Inverter device. Claims 1 to 3 include the suppression value calculation unit including a selection unit for selecting a coefficient of the torque suppression rate using the temperature detection value of the temperature detection unit and the rotation speed of the motor. The inverter device according to any one of the above items. The claim is characterized in that the control device includes a minimum selection processing unit that selects the minimum value of the torque command value of the output of the command value calculation unit and the torque suppression value of the output of the suppression value calculation unit. Item 4. The inverter device according to any one of Items 1 to 4.

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