JP2022037282A - Driving device and control method - Google Patents

Abstract

To provide a driving device capable of suppressing temperature rise of a heat source in a component which generates heat in a case of high-current driving of a driver part for increasing output torque from the driver part.SOLUTION: An embodiment of the invention includes: a driver part 3 for driving a load 8; a power conversion part 30 for supplying power to the driver part by converting power from a current source 2; a temperature detection part 11 for detecting a temperature nearby a heat source generating heat in the power conversion part or the driver part; and a control part 10 for controlling the power conversion part so as to output torque determined based on a command signal input from an input part 5 and the temperature acquired based on a detection result of the temperature detection part. The control part controls the power conversion part so as to output limited torque smaller than command torque corresponding to the command signal if the temperature acquired based on the detection result is in a limited state greater than a preset limit threshold value and less than a preset abnormal threshold value higher than the limit threshold value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a drive device and a control method.

The electric vehicle has a motor for driving a load and a drive device for controlling the motor and the like (see, for example, Patent Document 1 and Patent Document 2).

In such an electric vehicle, for example, when the torque output from the motor is increased according to the operation of the user at the time of starting the pitching on a slope, when the motor is driven at a low angular velocity and a high current flows. There is a problem that the temperature of the device or motor rises too much.

Japanese Unexamined Patent Publication No. 2009-113676 Japanese Unexamined Patent Publication No. 2014-168341

Various aspects of the present invention are a drive device capable of suppressing a temperature rise of a heat source of a component that generates heat when the drive unit is driven with a high current in order to increase the torque output from the drive unit, and a control method. The purpose is to provide.

Various aspects of the present invention will be described below.

[1] A drive unit that drives the load and
A power conversion unit that converts power from a current source and supplies power to the drive unit,
A temperature detection unit that detects the temperature in the vicinity of the heat source that generates heat in the power conversion unit or the drive unit, and
A control unit that controls the power conversion unit so that the drive unit outputs a command signal input from the torque input unit and a torque determined by the temperature obtained based on the detection result of the temperature detection unit. When,
Equipped with
The control unit
When the temperature obtained based on the detection result is in a restricted state equal to or higher than a preset limit threshold value and lower than a preset abnormal threshold value higher than the limit threshold value, a command corresponding to the command signal is given. A drive device characterized in that the power conversion unit is controlled so that a limit torque smaller than the torque is output from the drive unit.

[2] The control unit is
When the temperature obtained based on the detection result is equal to or higher than the abnormality threshold value, the power conversion unit is controlled so that the torque output from the drive unit becomes zero. The drive device according to the above [1].

[3] The control unit is
When the temperature obtained based on the detection result is in a normal state below the limit threshold value, the power conversion unit is controlled so that the command torque corresponding to the command signal is output from the drive unit. The drive device according to the above [1] or [2].

[4] Further provided is a storage unit that stores a target limit torque table in which the frequency of the current flowing through the drive unit and the target limit torque are associated with each other when the temperature obtained based on the detection result is the limit threshold. The drive device according to any one of the above [1] to [3].

[5] The control unit in the restricted state is
The frequency of the current flowing through the drive unit is acquired, and the frequency is obtained.
With reference to the target limit torque table stored in the storage unit, the limit torque is set so as to be equal to or larger than the magnitude of the target limit torque corresponding to the acquired frequency [4]. The drive device described in.

[6] The control unit in the restricted state is
A temperature difference value is calculated by integrating a positive adjustment coefficient into a value obtained by subtracting the limiting threshold value from the temperature obtained based on the detection result.
The frequency of the current flowing through the drive unit is acquired, and the frequency is obtained.
With reference to the target limit torque table stored in the storage unit, the target limit torque corresponding to the acquired frequency is calculated.
By adding the temperature difference value to the value obtained by subtracting the current torque currently output by the drive unit from the calculated target limit torque, a negative cut torque to be subtracted from the command torque is calculated. ,
The limit torque is calculated by adding the negative cut torque to the command torque.
The drive device according to the above [4], wherein the power conversion unit is controlled so that the limit torque is output from the drive unit.

[7] In the target limit torque table, the target limit torque is set to increase when the frequency of the current flowing through the drive unit is high, and the target limit torque is set to decrease when the frequency of the current flowing through the drive unit is low. The drive device according to any one of the above [4] to [6].

[8] The temperature obtained based on the detection result is the estimated control temperature obtained by the control unit.
The storage unit stores a saturation temperature information table that associates a combination of the current value flowing through the drive unit and the frequency of the current flowing through the drive unit with the saturation temperature, which is the maximum temperature at which the heat of the heat source saturates. And
The control unit
The current value flowing through the drive unit is acquired, and the frequency of the current flowing through the drive unit is acquired.
With reference to the saturation temperature information table stored in the storage unit, step a for calculating the current saturation temperature of the heat source corresponding to the combination of the current value and the frequency, and
Step c to calculate the current estimated heat source temperature by estimating the temperature of the heat source by using the current saturation temperature and the first coefficient, and
Step e to calculate the current estimated detection unit temperature that estimates the temperature in the vicinity of the heat source by using the current estimated heat source temperature and the second coefficient.
Step f to acquire the actual temperature detected by the temperature detection unit, and
The g step of calculating the temperature difference by subtracting the actual temperature from the current estimated detection unit temperature,
The h step of calculating the temperature correction value by multiplying the temperature difference by a preset temperature correction coefficient, and
It has a function to execute the i-step of calculating the estimated temperature for control by adding the temperature correction value to the current estimated heat source temperature.
The current estimated heat source temperature in step c is
When the current saturation temperature is equal to or higher than the past estimated heat source temperature, and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is equal to or higher than the first P threshold, the first coefficient is used. Calculated by the following formula 31 with 1P coefficient.
When the current saturation temperature is equal to or higher than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is less than the first P threshold, the first coefficient. Is the second P coefficient smaller than the first P coefficient, and is calculated by the following equation 32.
When the current saturation temperature is lower than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is equal to or less than the first N threshold, the first coefficient is used. Calculated by the following formula 33 with a 1N coefficient.
When the current saturation temperature is lower than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is larger than the first N threshold, the first coefficient is used. The second N coefficient is smaller than the first N coefficient, and it is calculated by the following formula 34.
The past estimated heat source temperature is a temperature calculated by the same calculation method as the current estimated heat source temperature before the first time.
The current estimated detection unit temperature in the e step is
When the current estimated heat source temperature is higher than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is equal to or larger than the second P threshold, the second coefficient is used. Calculated by the following formula 41 as the 3rd P coefficient.
When the current estimated heat source temperature is higher than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is less than the second P threshold, the second coefficient Is the 4th P coefficient smaller than the 3rd P coefficient, and is calculated by the following equation 42.
The second coefficient is when the current estimated heat source temperature is equal to or lower than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is equal to or less than the second N threshold. Is the 3rd N coefficient, and it is calculated by the following formula 43.
If the current estimated heat source temperature is equal to or lower than the past estimated heat source temperature, and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is larger than the second N threshold, the second coefficient is used. It is calculated by the following equation 44 with the 4N coefficient smaller than the 3N coefficient.
One of claims 4 to 7, wherein the past estimated detection unit temperature is a temperature calculated by the same calculation method as the current estimation detection unit temperature calculation method before the first time. The drive device described in.
Current estimated heat source temperature = 1st P coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 31)
Current estimated heat source temperature = 2nd P coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 32)
Current estimated heat source temperature = 1st N coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 33)
Current estimated heat source temperature = 2nd N coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 34)
Current estimated detector temperature = 3rd P coefficient × (current estimated heat source temperature-past estimated detector temperature) + past estimated detector temperature ... (Equation 41)
Current estimated detection unit temperature = 4th P coefficient × (current estimated heat source temperature-past estimated detection unit temperature) + past estimated detection unit temperature ... (Equation 42)
Current estimated detector temperature = 3N coefficient × (current estimated heat source temperature-past estimated detector temperature) + past estimated detector temperature ... (Equation 43)
Current estimated detector temperature = 4th N coefficient × (current estimated heat source temperature-past estimated detector temperature) + past estimated detector temperature ... (Equation 44)

[9] The a step, the c step, the e step, and the i step are repeated every first time.
The control device according to the above [8], wherein the f step, the g step, and the h step are repeated every second time longer than the first time.

[10] In the above [8] or [9], the first coefficient is a value larger than 0 and smaller than 1, and the second coefficient is a value larger than 0 and smaller than 1. The control device described.

[11] The control unit is
When the current value flowing through the drive unit is less than the preset switching threshold current, or the frequency of the current flowing through the drive unit is equal to or higher than the preset switching threshold frequency, it is obtained based on the detection result. The drive device according to any one of the above [8] to [10], wherein the temperature is not the estimated temperature for control but the actual temperature detected by the temperature detection unit.

[12] When the temperature obtained based on the detection result becomes equal to or higher than the abnormal threshold value, the control unit stops the drive unit until the operation of the control unit is reset. The drive device according to any one of the above [1] to [11], wherein the control of the drive unit is not restarted.

[13] The drive unit is a motor.
The power converter includes a bridge circuit that generates a motor drive voltage for driving the motor from a DC voltage supplied from the current source.
The control unit controls the power conversion unit so as to drive the motor by supplying the motor drive voltage to the motor.
The driving device according to any one of the above [1] to [12], wherein the temperature detecting unit is a thermistor for detecting a temperature in the vicinity of the heat source.

[14] The heat source is
It is a transistor constituting the bridge circuit of the power conversion unit, and is a transistor.
The thermistor is
The drive device according to the above [13], wherein the drive device is arranged close to the transistor.

[15] The heat source is
It is the coil of the motor.
The thermistor is
The drive device according to the above [13], wherein the drive device is arranged close to the coil.

[16] The drive device is loaded on an electric motorcycle and
The load is the wheel of the electric motorcycle.
The drive device according to any one of the above [13] to [15], wherein the motor is connected to the wheels of the electric motorcycle.

[17] The torque input unit includes an accelerator position sensor that detects an operation amount with respect to the accelerator by the user of the electric motorcycle and transmits it as an electric signal to the control unit.
The driving device according to the above [16], wherein the electric signal is the command signal.

[18] In a control method for controlling a power conversion unit that converts power from a current source and supplies power to a drive unit.
The temperature obtained based on the detection result by the temperature detection unit arranged in the vicinity of the heat source that generates heat in the power conversion unit or the drive unit is equal to or higher than a preset limit threshold value and higher than the limit threshold value in advance. When the limit state is less than the set abnormal threshold value, the power conversion unit is controlled so that the drive unit outputs a limit torque smaller than the command torque corresponding to the command signal input from the torque input unit. A control method characterized by that.

[19] The control unit is
When the temperature obtained based on the detection result is equal to or higher than the abnormality threshold value, the power conversion unit is controlled so that the torque output from the drive unit becomes zero. The control method according to the above [18].

According to various aspects of the present invention, a drive device capable of suppressing a temperature rise of a heat source of a component that generates heat when the drive unit is driven with a high current in order to increase the torque output from the drive unit, and a drive device. A control method can be provided.

It is a schematic diagram which shows the drive device which concerns on one aspect of this invention. It is a schematic diagram for demonstrating the electric vehicle provided with the drive device which concerns on one aspect of this invention. It is a figure which shows an example of the structure around the power conversion part 30c shown in FIG. It is a figure which shows the relationship between the temperature of a heat source, and the control of a motor in order to perform a temperature protection function. It is a figure which shows an example of the characteristic of the target limiting torque 57 at the limiting threshold value 51 shown in FIG. 4, and is the figure which shows the relationship between the target limiting torque at a limiting threshold value, and the frequency of the current flowing through a motor 3x. An example of the relationship between the current value of the motor 61, the actual thermistor temperature 62 detected by the thermistor S, the actual temperature 63 of the heat source Z, and the saturation temperature 64 of the heat source Z when the motor is driven at a predetermined rotation speed. It is a figure which shows. It is a figure which shows an example of the relationship between the current of a motor, and the saturation temperature of a heat source Z when the motor is driven at a predetermined rotation speed for a predetermined drive period. When controlling the drive of a motor as a drive unit, the control unit determines the temperature of the heat source, which is the reference for executing the temperature protection function, in the relationship between the current value (phase current value) of the motor and the frequency of the current flowing through the motor. It is a figure explaining the method of selecting the said estimated control temperature or the actual thermistor temperature according to. It is a figure which shows the structure around the power conversion part 30c which concerns on 3rd Embodiment. It is a figure which shows the relationship between the energization time and the temperature of a heat source when a motor is driven by a constant current and the temperature of a heat source rises. It is a figure which shows the relationship between the energization time and the temperature of a heat source when the temperature of a heat source drops even if a motor is driven by a constant current.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that the form and details thereof can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention is not construed as being limited to the description of the embodiments shown below.

For example, although the drive device will be described as the first embodiment, this drive device can also be applied to an electric vehicle control device that drives a load of an electric vehicle, and this drive device can be applied to a drive device other than the load of the electric vehicle. It can also be applied to a device that controls a drive unit that drives a load.

(First Embodiment)
<Drive device>
FIG. 1 is a schematic view showing a drive device according to an aspect of the present invention. FIG. 4 is a diagram showing the relationship between the temperature of the heat source and the control of the motor in order to execute the temperature protection function.

The drive device shown in FIG. 1 has a drive unit 3 that drives a load 8, a power conversion unit 30 that converts power from a current source 2 and supplies power to the drive unit 3, and heat generation by the power conversion unit 30 or the drive unit 3. It has a temperature detecting unit 11 that detects a temperature in the vicinity of a heat source to be generated. Further, the drive unit 3 drives a torque determined by a command signal input from the input unit (torque input unit) 5 for inputting torque and a temperature obtained based on the detection result of the temperature detection unit 11. A control unit 10 for controlling the power conversion unit 30 is provided so as to output from. The torque means a force in the direction of twisting a rod-shaped object such as a shaft. Further, the current source 2 may be, for example, a battery, the drive unit 3 may be, for example, a motor, and the load 8 may be, for example, a wheel.

The control unit 10 has a temperature obtained based on the detection result of the temperature detection unit 11 which is equal to or higher than the preset limit threshold value 51 shown in FIG. 4 and lower than the preset abnormal threshold value 52 which is higher than the limit threshold value 51. In the limited state 53 of, it is preferable to control the power conversion unit 30 so that the drive unit 3 outputs a limit torque 54 smaller than the command torque corresponding to the command signal input from the input unit 5. As a result, when the drive unit 3 is driven with a high current in order to increase the torque output from the drive unit 3 by the command signal input from the input unit 5, the temperature of the power conversion unit 30 or the drive unit 3 that generates heat becomes high. It is possible to suppress the rise too much. As a result, it is possible to prevent the parts from being damaged by the heat generated by the power conversion unit 30 or the drive unit 3.

When the temperature obtained based on the detection result of the temperature detection unit 11 is equal to or higher than the abnormality threshold value 52 shown in FIG. 4, the control unit 10 makes the torque output from the drive unit 3 zero. In addition, it is preferable to control the power conversion unit 30. As a result, it is possible to prevent the operation of the drive unit 3 from being stopped and the temperature of the power conversion unit 30 or the drive unit 3 that generates heat from rising too high.

When the temperature obtained based on the detection result of the temperature detection unit 11 is the normal state 56 which is less than the limit threshold value 51 shown in FIG. 4, the control unit 10 responds to the command signal input from the input unit 5. The power conversion unit 30 may be controlled so that the command torque 58 is output from the drive unit 3. In such a normal state 56, the temperature of the power conversion unit 30 or the drive unit 3 that generates heat does not rise too much.

Further, the drive device shown in FIG. 1 has a storage unit 20 that stores a preset target limit torque table. In this target limit torque table, the frequency of the current flowing through the drive unit 3 and the target limit torque 57 are associated with each other when the temperature obtained based on the detection result of the temperature detection unit 11 is the limit threshold shown in FIG. It is a thing. By using this target limit torque 57, the minimum torque can be secured.

In the above limited state 53, the control unit 10 acquires the frequency of the current flowing through the drive unit 3, refers to the target limiting torque table stored in the storage unit 20, and refers to the target corresponding to the acquired frequency. The limit torque 54 may be set so as to be equal to or larger than the size of the limit torque 57. As a result, when the drive unit 3 is driven with a high current in order to increase the torque output from the drive unit 3 by the command signal input from the input unit 5, the temperature of the power conversion unit 30 or the drive unit 3 that generates heat becomes high. It is possible to secure the minimum torque while suppressing the rise too much.

(Second embodiment)
<Electric vehicle>

FIG. 2 is a schematic diagram for explaining an electric vehicle provided with a drive device according to an aspect of the present invention.

The electric vehicle of FIG. 2 is a vehicle that moves forward or backward by driving a motor 3x using electric power supplied from a battery 2a as a current source. The motor 3x is an example as a drive unit.

This electric vehicle is, for example, an electric two-wheeled vehicle such as an electric motorcycle, and more specifically, an electric two-wheeled vehicle in which a motor 3x and a load 8 such as a wheel are mechanically and directly connected without a clutch. The electric vehicle according to one aspect of the present invention is not limited to a two-wheeled vehicle, and may be, for example, a three-wheeled or four-wheeled electric vehicle.

The drive device shown in FIG. 1 is loaded on this electric vehicle. As shown in FIG. 2, this drive device includes a load 8, a motor 3x as a drive unit, a power conversion unit 30c that converts power from a battery 2a as a current source and supplies power to the motor 3x, and temperature detection. It has a control device 1 having a unit 11a and a control unit 10, and an accelerator position sensor (not shown) as a torque input unit. By loading the drive device on the electric vehicle in this way, power conversion that generates heat when the motor 3x is driven with a high current in order to increase the torque output from the motor 3x by the command signal input from the accelerator position sensor. It is possible to prevent the temperature of the portion 30c or the motor 3x from rising too high.
Further, as shown in FIG. 2, the electric vehicle includes an angle sensor 4, an assist switch 6, a meter (display unit) 7, and a charger 9.

Hereinafter, each component of the electric vehicle of FIG. 2 will be described in detail.

The control device 1 is a device that controls each configuration of the electric vehicle, and is loaded on, for example, an electric motorcycle (electric vehicle) as described above. In this case, the load 8 is a wheel of an electric motorcycle. The motor 3x is connected to the wheels of the electric motorcycle. Then, the control device 1 can control the power conversion unit 30 that converts power from the battery 2a and supplies power to the motor 3x. By controlling the power conversion unit 30c, it is possible to control the motor 3x that drives the load 8.

The control device 1 may be configured as an ECU (Electronic Control Unit) that controls the entire electric vehicle.

As shown in FIG. 2, the control device 1 includes a control unit 10a, a storage unit 20a, and a temperature detection unit 11a. The temperature detection unit 11a is a thermistor S for detecting the temperature in the vicinity of the heat source Z of the power conversion unit 30c (see FIG. 3). However, as will be described later, the control device 1 may include a thermistor S for detecting the temperature in the vicinity of the heat source Z of the motor 3x.

Then, the battery 2a supplies electric power to the motor 3x that rotates the load 8 of the electric vehicle. More specifically, the battery 2a supplies DC power to the power conversion unit 30c. The battery 2a is, for example, a lithium ion battery, but may be another type of battery. Further, the battery 2a may include a lead battery for supplying an operating voltage to the control unit 10a.

Further, the battery 2a includes a battery management unit (BMU). The battery management unit transmits battery information regarding the voltage of the battery 2a and the state (charge rate, etc.) of the battery 2a to the control unit 10a. The number of batteries 2a is not limited to one, and may be plural. That is, the electric vehicle may be provided with a plurality of batteries 2a connected in parallel or in series with each other.

Further, the motor 3x is a three-phase motor driven by AC power supplied from the power conversion unit 30c. The motor 3x is mechanically connected to the wheel as the load 8 and rotates the wheel in a desired direction. In this embodiment, the motor 3x is mechanically directly connected to the wheels without the intervention of a clutch (including a transmission mechanism). The type of motor 3x is not particularly limited.

Further, the angle sensor 4 is a sensor that detects the rotation angle of the rotor of the motor 3x. N-pole and S-pole magnets (sensor magnets) are alternately attached to the peripheral surface of the rotor (not shown).

The angle sensor 4 is composed of, for example, a Hall element, and is adapted to detect a change in the magnetic field accompanying the rotation of the motor 3x.

Further, the accelerator position sensor detects the amount of operation of the electric vehicle (motorcycle) with respect to the accelerator (hereinafter referred to as "accelerator operation amount") and transmits it as an electric signal to the control unit 10a. The accelerator operation amount corresponds to the throttle opening of the engine vehicle.

With the above accelerator position sensor, the accelerator operation amount becomes large when the user wants to accelerate, and the accelerator operation amount becomes small when the user wants to decelerate.

Further, the assist switch 6 is a switch operated when the user requests assistance of the electric vehicle. When the assist switch 6 is operated by the user, the assist switch 6 transmits an assist request signal to the control unit 10a.

Further, the meter (display unit) 7 is a display (for example, a liquid crystal panel) provided in the electric vehicle, and displays various information. The meter 7 is provided, for example, on the steering wheel (not shown) of the electric vehicle. Information such as the traveling speed of the electric vehicle, the remaining amount of the battery 2a, the current time, the total mileage, and the remaining mileage is displayed on the meter 7. The remaining mileage indicates how far the electric vehicle can travel.

Further, the charger 9 has a power plug (not shown) and a converter circuit (not shown) that converts an AC power supply supplied via the power plug into a DC power supply. The battery 2a is charged by the DC power converted by the converter circuit. The charger 9 is communicably connected to the control device 1 via, for example, a communication network (CAN or the like) in the electric vehicle.

Further, the control unit 10a is configured to input / output information from various devices connected to the control device 1.

Specifically, the control unit 10a receives various signals output from the battery 2a, the angle sensor 4, the accelerator position sensor, the assist switch 6, and the charger 9. The control unit 10a outputs a signal to be displayed on the meter 7. Further, the control unit 10a controls the motor 3x via the power conversion unit 30c. The details of the control unit 10a will be described later.

Further, the storage unit 20a stores information used by the control unit 10a (various maps described later, etc.) and a program for operating the control unit 10a. The storage unit 20a is, for example, a non-volatile semiconductor memory, but is not limited thereto. The storage unit 20a may be incorporated as a part of the control unit 10a.

In particular, the storage unit 20a is designed to store a saturation temperature information table (not shown). This saturation temperature information table shows a combination of the current value flowing through the motor 3x and the frequency of the current flowing through the motor 3x when the motor 3x is continuously driven at a predetermined rotation speed for a preset drive period, and the motor. It is a table associating with the saturation temperature which is the maximum temperature at which the heat of the heat source Z which generates heat when driving 3x is saturated.
The above-mentioned "combination of the frequency of the current value flowing through the motor 3x and the frequency of the current flowing through the motor 3x" may be replaced with "a combination of the phase current value of the phase current of the motor 3x and the rotation speed of the motor 3x".

Further, as will be described later, the storage unit 20a stores a target limit torque table in which the frequency of the current flowing through the motor 3x as the drive unit and the target limit torque are associated with each other when the heat source temperature is the limit threshold. It has become. The above-mentioned "frequency of the current flowing through the motor 3x" may be replaced with "the rotation speed of the motor 3x".

Then, the saturation temperature described above is a bridge of the power conversion unit 30c so that the control unit 10a continuously energizes the motor 3x (continuous current (phase current) flows) at least during the above-mentioned drive period. It is the temperature of the heat source Z that is saturated by controlling the circuit X (see FIG. 6).

Further, the power conversion unit 30c converts the DC power output from the battery 2a into AC power and supplies it to the motor 3x (see FIG. 3).

Then, the power conversion unit 30c, which is an inverter device, provides a three-phase bridge circuit X including a first to third half bridge that generates a motor drive voltage for driving the motor 3x from the DC voltage supplied from the battery 2a. Be prepared. By providing this bridge circuit X, the phase and wave height of the sine wave required to drive the motor can be controlled, and heat generation can be minimized by efficiently using the motor.

As shown in FIG. 3, the first to third half bridges have high-side transistors (semiconductor switches Q1, Q3, Q5) and low-side transistors (semiconductor switches Q2, Q4, Q6) connected in series, respectively. include.

The control terminals of these semiconductor switches Q1 to Q6 are electrically connected to the control unit 10a. A smoothing capacitor C is provided between the power supply terminal 30a and the power supply terminal 30b. The semiconductor switches Q1 to Q6 are, for example, MOSFETs, IGBTs, or the like.

Then, as shown in FIG. 3, the semiconductor switch Q1 is connected between the power supply terminal 30a to which the positive electrode of the battery 2a is connected and the input terminal 3a of the motor 3x.

Similarly, the semiconductor switch Q3 is connected between the power supply terminal 30a and the input terminal 3b of the motor 3x.

The semiconductor switch Q5 is connected between the power supply terminal 30a and the input terminal 3c of the motor 3x.

The semiconductor switch Q2 is connected between the input terminal 3a of the motor 3x and the power supply terminal 30b to which the negative electrode of the battery 2a is connected.

Similarly, the semiconductor switch Q4 is connected between the input terminal 3b of the motor 3x and the power supply terminal 30b.

The semiconductor switch Q6 is connected between the input terminal 3c of the motor 3x and the power supply terminal 30b.

The input terminal 3a is a U-phase input terminal of the motor 3x, the input terminal 3b is a V-phase input terminal of the motor 3x, and the input terminal 3c is a W-phase input terminal of the motor 3x.

Further, the control unit 10a controls the power conversion unit 30c so that the command torque corresponding to the command signal input from the outside is output from the motor 3x, and supplies the motor drive voltage to the motor 3x to supply the motor. It can drive 3x.

Here, as described above, the accelerator position sensor detects the amount of operation of the electric vehicle (motorcycle) with respect to the accelerator and transmits it to the control unit 10 as an electric signal. The electrical signal output by the accelerator position sensor corresponds to the command signal in this case.

The control unit 10a controls on / off of the semiconductor switches Q1 to Q6 of the power conversion unit 30c according to the motor stage. As a result, the DC power supplied from the battery 2a is converted into AC power.

The thermistor S is arranged in the vicinity of the heat source Z so as to detect the temperature of the heat source Z (see FIG. 3). Then, as shown in FIG. 3, the heat source Z is the transistors Q1 to Q6 constituting the bridge circuit X of the power conversion unit 30c.

In this embodiment, the thermistor S is arranged close to the transistors Q1 to Q6. By using the thermistor S, the board design is easy and the temperature can be read by the resistance change due to the temperature, so the conversion control can be simply constructed.

In particular, as shown in FIG. 3, the thermistor S includes three thermistors S1, S2, S3. The thermistor S1 is arranged in the vicinity of the high-side transistor Q1 of the first half bridge. Further, the thermistor S2 is arranged in the vicinity of the high side transistor Q3 of the second half bridge. Further, the thermistor S3 is arranged in the vicinity of the high side transistor Q5 of the third half bridge.

As described above, the thermistors S (S1, S2, S3) are arranged in the vicinity of the high-side transistors Q1, Q3, and Q5 of the first to third half bridges, which are said to have a particularly large calorific value.

<Execution of temperature protection function>
FIG. 4 is a diagram showing the relationship between the temperature of the heat source and the control of the motor in order to execute the temperature protection function. FIG. 5 is a diagram showing an example of the characteristics of the target limiting torque 57 at the limiting threshold value 51 shown in FIG.

As shown in FIG. 5, the target limiting torque 57 at the limiting threshold and the frequency of the current flowing through the motor 3x have a quadratic function relationship. That is, the target limiting torque 57 increases when the frequency of the current flowing through the motor 3x increases when the heat source temperature is the limiting threshold value 51 shown in FIG. 4, while it decreases when the frequency of the current flowing through the motor 3x decreases. (See FIG. 5).
In addition, the above-mentioned and the following "frequency of the current flowing through the motor 3x" may be replaced with "the rotation speed of the motor 3x". Further, the heat source temperatures described above and below are temperatures obtained based on the detection results of the thermistor S as a temperature detection unit.

Further, the storage unit 20a stores a target limiting torque table in which the frequency of the current flowing through the motor 3x and the target limiting torque 57 are associated with each other when the heat source temperature is the limiting threshold value 51. Therefore, the control unit 10a can acquire the target limit torque 57 associated with the frequency of the current flowing through the motor 3x by referring to the target limit torque table stored in the storage unit 20a.

Further, in the target limit torque table, the target limit torque 57 is set to increase when the frequency of the current flowing through the motor 3x as a drive unit is high, and the target limit torque 57 is set to decrease when the frequency of the current flowing through the motor 3x is low. It should be done. As a result, the minimum torque at the limit threshold value 51 can be secured.
It should be noted that "the target limit torque 57 is set to increase when the frequency of the current flowing through the motor 3x increases, and the target limit torque 57 decreases when the frequency of the current flowing through the motor 3x decreases". The target limit torque is set to increase when the rotation speed of the motor 3x is high, and the target limit torque is set to decrease when the rotation speed of the motor 3x is low. "

Here, in order to execute the temperature protection function, as shown in FIG. 4, the control unit 10a has a heat source temperature obtained based on the detection result of the thermistor S having a preset limit threshold value 51 or more. The power conversion unit 30c is controlled so as to output a limit torque 54 smaller than the command torque corresponding to the command signal described above in the limit state 53 which is higher than the limit threshold 51 and less than the preset abnormality threshold 52. , Drives the motor 3x.

As the heat source temperature described above and below, the estimated control temperature described later or the actual thermistor temperature (actual temperature) may be used.

Explaining the above-mentioned limiting torque 54 in detail, first, the control unit 10a acquires the frequency of the current flowing through the motor 3x.

Further, the above-mentioned "acquiring the frequency of the current flowing through the motor 3x" may be replaced with "acquiring the rotation speed of the motor 3x". The control unit 10a can acquire the rotation speed of the motor 3x, for example, based on a signal output by a Hall element (not shown) provided in the motor 3x according to the rotation of the motor 3x.

Next, the control unit 10a refers to the target limit torque table stored in the storage unit 20a so that the limit torque becomes equal to or larger than the size of the target limit torque 57 corresponding to the acquired frequency. Set. In addition, this "acquired frequency" may be replaced with "acquired rotation speed".

As a result, it is possible to suppress the temperature of the transistors Q1 to Q6, which are the heat sources Z, from rising and being damaged, and to continue the running of the electric vehicle while reducing the torque of the motor 3x. The reason for setting the target limit torque to be equal to or larger than the size of the limit state 57 is not to try to lower the temperature range of the limit state 53 shown in FIG. 4 to the temperature of the normal state 56, but to exceed the limit state 53 and make an abnormality. This is because the purpose is to prevent the temperature range of the state 55 from being reached. When set to be less than the magnitude of the target limit torque 57, the purpose is to lower the temperature from the limit state 53 to the normal state 56, but in such a case, the user can only output a torque considerably lower than the command torque. This is because the user's satisfaction cannot be obtained.
The limiting torque 54 is set so that the heat source temperature does not exceed the abnormal threshold value 52.

According to the above description, the operation of the control unit 10a in the restricted state 53 increases the torque of the motor 3x by the user's operation, and a high current flows in the state where the motor 3x has a low angular speed to drive the motor 3x. When the temperature of the heat source Z, which sometimes generates heat, rises above the limit threshold value 51 for executing the temperature protection function, the temperature rise can be suppressed by limiting the output torque of the motor regardless of the user's operation. ..

On the other hand, when the heat source temperature is in the abnormal state 55 which is equal to or higher than the abnormal threshold value 52, the control unit 10a is a power conversion unit so that the torque output from the motor 3x becomes zero regardless of the command signal. 30c is controlled to stop the motor 3x (see FIG. 4).

For example, the control unit 10a may determine the abnormal state 55 in which the heat source temperature is equal to or higher than the abnormality threshold value 52 as a state in which an abnormality has occurred in the system of the control unit 10a. Thereby, for example, when an abnormality occurs in the transistors Q1 to Q6, the running of the electric vehicle can be appropriately stopped.

Further, when the heat source temperature exceeds the abnormal threshold value 52, the control unit 10a restarts the control of the motor 3x until the operation of the control unit 10a is reset, for example, after stopping the motor 3x. You may not do it. By doing so, if heat that exceeds the abnormal threshold that cannot occur within the designed normal range is generated, it is judged that the system is abnormal, and it can be safely stopped before it is damaged. ..

When the operation of the control unit 10a in the abnormal state 55 causes an abnormality in the control unit 10a, the power conversion unit 30c, or the like and the heat source Z reaches a very high temperature, the motor 3x can be appropriately stopped. can.

The control unit 10a controls the power conversion unit 30c so that the command torque 58 corresponding to the command signal is output in the normal state 56 where the heat source temperature is less than the limit threshold value 51, and the motor. Drive 3x (see FIG. 4).

By the operation of the control unit 10a in the normal state 56, the command torque 58 corresponding to the command signal based on the user's operation can be output from the motor.

<Example of operation with limited torque in the limited state>
Here, an example of an operation in which the control unit 10a calculates the limit torque 54 and drives the motor 3x with the limit torque 54 in the above-mentioned limited state will be described.

First, in the restricted state shown in FIG. 4, the control unit 10a subtracts the limiting threshold value 51 (for example, 130 ° C.) from the above heat source temperature (for example, 150 ° C.) as shown in the following (formula A). By accumulating a positive adjustment coefficient (for example, 0.02), a temperature difference value (for example, 0.4), which is a parameter of the temperature difference between the heat source temperature and the limit threshold value 51, is calculated.

Further, the above-mentioned adjustment coefficient is set so that the heat source temperature falls within the range from the limit threshold value 51 to the abnormal threshold value 52, for example, in a state where the torque output by the motor 3x is the limit torque 54.

Temperature difference value = Positive adjustment coefficient x (heat source temperature-limit threshold) ... (Equation A)

Next, the control unit 10a acquires the frequency of the current flowing through the motor 3x as the drive unit or the rotation speed of the motor 3x (for example, 1000 rpm).
Next, the target limit torque 57 (for example, 20 Nm) corresponding to the acquired frequency is calculated with reference to the target limit torque table stored in the storage unit 20a.

Next, as shown in the following (Equation B), the control unit 10a subtracts the current torque (for example, 26 Nm) currently output by the motor 3x from the target limit torque 57 described above. By integrating the above temperature difference value (for example, 0.4), a negative cut torque (for example, -2.4 Nm) for subtracting from the command torque 58 is calculated.

Cut torque = temperature difference value x (target limit torque-current torque) ... (Equation B)

Next, the control unit 10a adds a negative cut torque (for example, -2.4 Nm) to the command torque 58 (for example, 26 Nm) as shown in the following (formula C) (that is, the command torque). By subtracting the absolute value of the cut torque from), the limit torque 54 (for example, 23.6 Nm) is calculated.

Limit torque = command torque + cut torque ... (Formula C)

Then, the control unit 10a controls the power conversion unit 30c so as to output the limit torque 54 (for example, 23.6 Nm) to drive the motor 3x, whereby the heat source temperature is set to the limit threshold value 51 (for example, 130). It is possible to keep the temperature within the range from the abnormality threshold value 52 (for example, 160 ° C.).

As a result, the output torque of the motor is increased by the user's throttle operation, and when a high current flows in the motor at a low angular speed and the temperature of the heat source rises above the threshold for executing the temperature protection function, the user's throttle By limiting the output torque of the motor regardless of the operation, it is possible to suppress the temperature rise of the heat source and continue the running of the electric vehicle.

<Method of estimating the heat source temperature used when executing the temperature protection function>
An example of a method of estimating the heat source temperature used when executing the temperature protection function by the above-mentioned control device 1 will be described.
Here, consider a physical model based on heat conduction between the on-resistance of the transistor that is the heat source Z, the temperature rise due to the current of the motor 3x as the drive unit, the heat capacity of the unit, and the ambient temperature of the unit. Then, the temperature of the transistor is estimated from the saturation temperature when the time has elapsed until the heat of the heat source is saturated. In order to prevent the deviation between the estimated temperature and the actual temperature due to the calculation error, the method using the actual temperature is used (see FIG. 6).
The above-mentioned and the following "motor 3x current" may be replaced with "motor 3x phase current".

First, in order to implement the temperature protection function, the control unit 10a acquires the current value flowing through the motor 3x (the phase current of the motor 3x is detected and the phase current value (for example, 100A)), and the current flowing through the motor 3x. Frequency (or the number of revolutions of the motor 3x (eg 1000 rpm)).

In addition, when detecting the current (phase current), in 120 ° energization and 180 ° energization, each current is specified for each of the six stages specified by the on / off combination of each transistor Q1 to Q6 of the motor 3x. The current value (phase current value) may be acquired by acquiring the peak current of (each phase current), removing the switching noise, and averaging the peak current.

As described above, the storage unit 20a determines the current value (phase current value) flowing through the motor 3x and the motor 3x when the motor 3x is continuously driven for a preset drive period at a predetermined rotation speed. Stores a saturation temperature information table that associates the combination of the frequency of the flowing current (or the number of revolutions of the motor 3x) with the saturation temperature, which is the maximum temperature at which the heat of the heat source Z that generates heat when driving the motor 3x is saturated. (See Fig. 7).

(Step a) The control unit 10a refers to the saturation temperature information table stored in the storage unit 20a, and refers to the acquired current value (phase current value; for example 100A) and the acquired frequency (or rotation speed (for example, 1000 rpm)). The current saturation temperature (eg, 90 ° C.) of the heat source Z corresponding to (associating) with is calculated.

In this way, the current saturation temperature of the heat source Z is calculated with reference to the preset saturation temperature information table based on the current current value (phase current value) and frequency (or rotation speed) measurement data. do.

Next, as shown in the following (Equation 1), the control unit 10a uses a first coefficient (time constant) based on the relationship of the first-order delay of the time change of the temperature of the heat source Z with respect to the current saturation temperature. , The current estimated heat source temperature is calculated as the temperature of the heat source Z tentatively estimated. That is, as shown in FIG. 6, the temperature of the heat source is estimated by using the time constant (first coefficient) based on the relationship 65 of the first-order lag with respect to the current saturation temperature.
The first coefficient is, for example, a value larger than 0 and smaller than 1. This first coefficient can correct the first-order lag with respect to the current saturation temperature.

The method for calculating the current estimated heat source temperature described above will be described in detail below.
First, the first coefficient will be described in detail below. FIG. 10 is a diagram showing the relationship between the energization time and the temperature of the heat source when the motor is driven with a constant current and the temperature of the heat source rises. FIG. 11 is a diagram showing the relationship between the energization time and the temperature of the heat source when the temperature of the heat source drops even if the motor is driven with a constant current.

(Step b) The current saturation temperature is compared with the past estimated heat source temperature (for example, 100 ° C.) calculated before the first time (for example, 10 ms) (once before). At this time, if the current saturation temperature is equal to or higher than the past estimated heat source temperature (formula a), it is determined that the temperature of the heat source rises. The first coefficient at this time is positive (P).

(Current saturation temperature-past estimated heat source temperature) ≧ 0 ・ ・ ・ (Equation a)

The past estimated heat source temperature is a temperature calculated by the same method as the current estimated heat source temperature calculation method before the first time. If the estimated heat source temperature in the past has not been calculated, the actual thermistor temperature detected by the thermistor S may be used.

When the first coefficient is positive (P) and the temperature difference between the current saturation temperature and the past estimated heat source temperature is the P slope threshold (first P threshold; for example, 20 ° C.) or more, the following (Equation b) Judges as the following (i) where the temperature rise of the heat source is rapid. The P slope threshold is also referred to as.

(Current saturation temperature-past estimated heat source temperature) ≧ P slope threshold ・ ・ ・ (Equation b)

(i) When the temperature of the heat source rises sharply toward the current saturation temperature (reference numeral 81 shown in FIG. 10), the P coefficient (steep) is used as the first coefficient. This P coefficient (sudden) is, for example, 0.05. This P coefficient (sudden) is also referred to as a first P coefficient.

Further, when the first coefficient is positive (P), the temperature difference between the current saturation temperature and the past estimated heat source temperature is less than the P slope threshold value (first P threshold value; for example, 20 ° C.) below (Equation c). In the case of, it is judged that the temperature rise of the heat source is gradual (ii) below.

(Current saturation temperature-past estimated heat source temperature) <P slope threshold ... (Equation c)

(ii) When the temperature of the heat source gradually rises toward the current saturation temperature (reference numeral 82 shown in FIG. 10), the P coefficient (slow) is used as the first coefficient. This P coefficient (loose) is, for example, 0.03. This P coefficient (slow) is smaller than the P coefficient (sudden) and is also called the second P coefficient.

Further, when the current saturation temperature is lower than the past estimated heat source temperature (Equation d), it is judged that the temperature of the heat source drops. The first coefficient at this time is negative (N).

(Current saturation temperature-past estimated heat source temperature) <0 ... (Equation d)

When the first coefficient is negative (N), the temperature difference between the current saturation temperature and the past estimated heat source temperature is equal to or less than the N slope threshold (first N threshold; for example, −30 ° C.) of the following (Equation e). In this case, it is judged that the temperature of the heat source drops sharply in (iii) below.

(Current saturation temperature-past estimated heat source temperature) ≤ N slope threshold ... (Equation e)

(iii) When the temperature of the heat source drops sharply toward the current saturation temperature (reference numeral 83 shown in FIG. 11), the N coefficient (steep) is used as the first coefficient. This N coefficient (sudden) is, for example, 0.06. This N coefficient (sudden) is also referred to as the first N coefficient.

Further, when the first coefficient is negative (N), the temperature difference between the current saturation temperature and the past estimated heat source temperature is larger than the N slope threshold (first N threshold; for example, −30 ° C.) or less (Equation f). In the case of, it is judged that the temperature drop of the heat source is gradual (iv) below.

(Current saturation temperature-past estimated heat source temperature)> N slope threshold ... (Equation f)

(iv) When the temperature of the heat source gradually decreases toward the current saturation temperature (reference numeral 84 shown in FIG. 11), the N coefficient (slow) is used as the first coefficient. This N coefficient (slow) is, for example, 0.04. The N coefficient (slow) is smaller than the N coefficient (sudden) and is also referred to as a second N coefficient.

Based on the above judgment, any one of the P coefficient (sudden) to the N coefficient (slow) of (i) to (iv) above is used as the first coefficient.
Since the first coefficient is a time constant, the coefficient is complicated when the temperature rises or falls, but the calculation load can be reduced by approximating the time constant to the above four cases. At the same time, the accuracy of temperature estimation of the heat source can be improved.

(Step c) Next, as shown in the following (Equation 1), the first coefficient determined as described above (that is, P coefficient (sudden), P coefficient (slow), N coefficient (sudden), N By multiplying the coefficient (slow)) by the difference between the current saturation temperature (for example, 90 ° C.) calculated by the above method and the past estimated heat source temperature (for example, 100 ° C.) and adding it to the past estimated heat source temperature, it is tentatively added. The current estimated heat source temperature (eg, 99.6 ° C.) is calculated as the estimated heat source temperature.

Current estimated heat source temperature = 1st coefficient (one of P coefficient (sudden), P coefficient (slow), N coefficient (sudden), N coefficient (slow)) × (current saturation temperature-past estimated heat source temperature) + past Estimated heat source temperature ・ ・ ・ (Equation 1)

In this way, the temperature of the transistor, which is the heat source Z, is tentatively estimated from the current saturation temperature using the first coefficient obtained by counting the time constant.

Next, as shown in the following (Equation 2), the control unit 10a has a second coefficient based on the relationship of the first-order delay of the time change of heat conduction from the heat source Z to the thermistor S and different from the first coefficient described above. By using (time constant), the currently estimated thermistor temperature, which is the tentatively estimated temperature of the thermistor, is calculated. That is, as shown in FIG. 6, the actual thermistor temperature is estimated by using a time constant (second coefficient) based on the relationship 66 of the first-order delay of the time change of heat conduction from the heat source Z to the thermistor S.
The current estimated thermistor temperature is also referred to as the current estimated detector temperature.
Further, this second coefficient is, for example, a value larger than 0 and smaller than 1. This second coefficient can correct the first-order delay of the time change of heat conduction from the heat source Z to the thermistor S.

The method of calculating the above-mentioned current estimated thermistor temperature (currently estimated detection unit temperature) will be described in detail below.

First, the second coefficient will be described in detail below.
(Step d) The current estimated heat source temperature calculated by the above (Equation 1) is compared with the past estimated thermistor temperature calculated before the first time (for example, 10 ms) (one time before). At this time, if the current estimated heat source temperature is higher than the past estimated thermistor temperature (Equation g), it is determined that the temperature of the thermistor rises. The second coefficient at this time is positive (P).

(Current estimated heat source temperature-Past estimated thermistor temperature) ≧ 0 ・ ・ ・ (Equation g)

The past estimated thermistor temperature is a temperature calculated by the same method as the current estimated thermistor temperature calculation method before the first time. If the past estimated thermistor temperature has not been calculated, the actual thermistor temperature detected by the thermistor S may be used.

When the second coefficient is positive (P) and the temperature difference between the current estimated heat source temperature and the past estimated thermistor temperature is the P slope threshold (second P threshold; for example, 20 ° C.) or more, the following (Equation h) Judges the following (i) that the temperature rise of the thermistor is rapid.

(Current estimated heat source temperature-Past estimated thermistor temperature) ≧ P slope threshold ・ ・ ・ (Equation h)

(i) When the temperature of the thermistor rises sharply, the P coefficient (sudden) is used as the second coefficient. This P coefficient (sudden) is, for example, 0.03. This P coefficient (sudden) is also referred to as a third P coefficient.

Further, when the second coefficient is positive (P), the temperature difference between the current estimated heat source temperature and the past estimated thermistor temperature is less than the P slope threshold value (second P threshold value; for example, 20 ° C.) below (Equation i). In the case of, it is judged that the temperature rise of the thermistor is gradual (ii) below.

(Current estimated heat source temperature-Past estimated thermistor temperature) <P slope threshold ... (Equation i)

(ii) When the temperature of the thermistor rises slowly, the P coefficient (slow) is used as the second coefficient. This P coefficient (slow) is, for example, 0.02. This P coefficient (slow) is smaller than the P coefficient (sudden) and is also referred to as a fourth P coefficient.

Further, when the current estimated heat source temperature is lower than the past estimated thermistor temperature (Equation j), it is determined that the temperature of the thermistor drops. The second coefficient at this time is negative (N).

(Current estimated heat source temperature-Past estimated thermistor temperature) <0 ... (Equation j)

When the second coefficient is negative (N), the temperature difference between the current estimated heat source temperature and the past estimated thermistor temperature is N inclination threshold (second N threshold; for example, −10 ° C.) or less. In this case, it is judged that the temperature of the thermistor drops sharply in (iii) below.

(Current estimated heat source temperature-Past estimated thermistor temperature) ≤ N slope threshold ... (Equation k)

(iii) When the temperature of the thermistor drops sharply, the N coefficient (steep) is used as the second coefficient. This N coefficient (sudden) is, for example, 0.02. The N coefficient (sudden) is also referred to as the third N coefficient.

Further, when the second coefficient is negative (N), the temperature difference between the current estimated heat source temperature and the past estimated thermistor temperature is larger than the N slope threshold (second N threshold; for example, −10 ° C.) or less (formula m). In the case of, it is judged that the temperature drop of the thermistor is gradual (iv) below.

(Current estimated heat source temperature-Past estimated thermistor temperature)> N slope threshold ... (Equation m)

(iv) When the temperature of the thermistor drops slowly, the N coefficient (slow) is used as the second coefficient. This N coefficient (slow) is, for example, 0.01. The N coefficient (slow) is smaller than the 3rd N coefficient and is also referred to as the 4th N coefficient.

Based on the above judgment, any one of the P coefficient (sudden) to the N coefficient (slow) of (i) to (iv) above is used as the second coefficient.
Since the second coefficient is a time constant, the coefficient is complicated when the temperature rises or falls, but the calculation load can be reduced by approximating the time constant to the above four cases. At the same time, the accuracy of temperature estimation of the heat source can be improved.

(Step e) Next, as shown in the following (Equation 2), the second coefficient determined as described above (that is, P coefficient (sudden), P coefficient (slow), N coefficient (sudden), N By multiplying the coefficient (loose)) by the difference between the current estimated heat source temperature (for example, 46.65 ° C.) calculated by the above (Equation 1) and the past estimated thermista temperature (for example, 30 ° C.), and adding it to the past estimated thermista temperature. , The current estimated thermister temperature (eg, 30.5), which is the tentatively estimated temperature of the thermista, is calculated.

Current estimated thermistor temperature = 2nd coefficient (one of P coefficient (sudden), P coefficient (slow), N coefficient (sudden), N coefficient (slow)) × (current estimated heat source temperature-past estimated thermistor temperature) + past Estimated thermistor temperature ... (Equation 2)

In this way, the temperature of the thermistor S is estimated using the second coefficient obtained by counting the time constant.

(F step) Next, the control unit 10a acquires the actual thermistor temperature (for example, 30.9 ° C.) detected by the thermistor S.

(Step g) Next, as shown in the following (Equation 3), the control unit 10a receives the actual thermistor temperature (for example, 30.5 ° C.) detected by the thermistor S from the current estimated thermistor temperature (for example, 30.5 ° C.) of the above (Equation 2). For example, by subtracting 30.9 ° C.), the temperature difference (for example, 0.4 ° C.) is calculated.

Current estimated thermistor temperature-actual thermistor temperature = temperature difference ... (Equation 3)

The actual thermistor temperature is also referred to as an actual temperature.

(H step) Next, as shown in the following (Equation 4), the control unit 10a multiplies the preset temperature correction coefficient (for example, 0.9) by the temperature difference calculated in the above (Equation 3). By doing so, it is possible to calculate a temperature correction value (for example, 0.36 ° C.) for correcting the current estimated heat source temperature (for example, 46.65 ° C.) of the above (Equation 1).

Temperature difference x temperature correction coefficient = temperature correction value ... (Equation 4)

The temperature correction coefficient is a ratio that reflects the temperature difference in the estimated temperature for control from the type of the temperature detection unit (for example, thermistor) and the variation of the individual.

(Step i) Next, as shown in the following (Equation 5), the control unit 10a controls by adding the temperature correction value of the above (Equation 4) to the current estimated heat source temperature of the above (Equation 1). Estimated temperature (for example, 47.01 ° C.) is calculated.

Current estimated heat source temperature + temperature correction value = estimated temperature for control ... (Equation 5)

The above steps (a) to (e) and (i) are repeated every first time (for example, every 10 ms), and the above (steps) to (h) are repeated every second time (for example, every 10 ms). Repeat every 100 ms). As a result, the accuracy of the estimated temperature for control is maintained by calculating the temperature correction value for correcting the temperature error (step f) to (step h) every second time, which is longer than the first time. While doing so, the load on the control unit can be reduced. Since the temperature correction value in (step h) can be obtained only every 100 ms, the same value is used 10 times as the temperature correction value used in (step i) performed every 10 ms.
Further, the control estimated temperature obtained every first time (for example, every 10 ms) and the current estimated heat source temperature of the calculation process are stored in the storage unit, and the temperature obtained every second time (for example, every 100 ms). The correction value and the current estimated thermistor temperature in the calculation process are stored in the storage unit. Further, the current saturation temperature obtained every first time may be stored in the storage unit, and the actual temperature obtained every second time may also be stored in the storage unit.

The past estimated thermistor temperature may be returned to the actual thermistor temperature at regular intervals. The reason is that the error of the estimated control temperature shifts due to the accumulation, and as a countermeasure, it is corrected and returned before the difference from the actual temperature due to the error greatly deviates. For example, the current estimated heat source temperature and the current estimated thermistor temperature are calculated every 10 msec, and the correction of the current estimated heat source temperature using the actual thermistor temperature is performed every 100 msec.

When performing the temperature protection function, the temperature of the heat source (transistor of the driver circuit) Z is estimated based on the detected temperature of the thermista, the current of the motor and the frequency of the current, taking into consideration the influence of heat conduction and ambient temperature. can do. As a result, the calculated estimated temperature for control can be used as the heat source temperature when the temperature protection function described above is executed.

Further, when executing the temperature protection function, by using the above-mentioned estimated control temperature estimated in consideration of the characteristics of the first-order lag with the saturation temperature of the heat source Z as a reference, the failure of the transistor which is the heat source Z can be prevented. It can be prevented more reliably.

<How to select the temperature of the heat source that is the standard for executing the temperature protection function>
FIG. 8 shows the temperature of a heat source, which is a reference for the control unit to execute the temperature protection function when controlling the drive of the motor as the drive unit, with respect to the current value of the motor and the frequency of the current flowing through the motor as the drive unit. It is a figure explaining the method of selecting the said estimated control temperature or the actual thermistor temperature (actual temperature) according to the relation with. That is, the control unit 10a may switch the temperature of the heat source, which is the reference for executing the temperature protection function, between the above-mentioned estimated temperature for control and the temperature (actual temperature) detected by the thermistor S.
In FIG. 8, the temperature of the heat source, which is the reference for executing the temperature protection function, is set to the above-mentioned estimated control temperature or the actual thermista temperature (actual temperature) according to the relationship between the current value of the motor and the frequency of the current flowing through the motor. However, the temperature of the heat source, which is the reference for executing the temperature protection function, is set to the above estimated temperature for control or the actual thermista temperature (actual temperature) according to the relationship between the phase current value of the motor and the rotation speed of the motor. ) Can also be selected.

In the first case, the control unit 10a has a current value of the current of the motor 3x of 45 or more, which is a preset switching threshold current, and the frequency of the current flowing through the motor 3x is less than a preset switching threshold frequency of 46. Based on the estimated control temperature 47, the electric power supplied from the power conversion unit 30c to the motor 3x is controlled. As a result, the drive of the motor 3x is controlled.
The above-mentioned "first case where the current value of the current of the motor 3x is equal to or more than the preset switching threshold current 45 and the frequency of the current flowing through the motor 3x is less than the preset switching threshold frequency 46". , "The first case where the phase current value flowing through the motor 3x is equal to or higher than the preset switching threshold current and the rotation speed of the motor 3x is less than the preset switching threshold current" may be replaced.
Further, the above-mentioned and the following "current value of the current of the motor 3x" may be replaced with "the phase current value of the phase current of the motor 3x".

In the first case described above, since the motor 3x is driven with a high current and a low frequency, the temperature detected by the thermistor S cannot sufficiently follow the actual temperature of the heat source Z. However, in such a case, the power conversion unit 30c controls the drive of the motor 3x while executing the temperature protection function based on the above-mentioned estimated temperature for control calculated by estimating the temperature of the heat source more accurately. do. This makes it possible to prevent damage to the power conversion unit 30c having a heat source.

On the other hand, in the second case where the current value of the current of the motor 3x is less than the switching threshold current 45 or the frequency of the current flowing through the motor 3x is the switching threshold frequency 46 or more, the control unit 10a detects it by the thermista S. Based on the actual thermister temperature (actual temperature) 50, the electric power supplied from the power conversion unit 30c to the motor 3x is controlled. As a result, the drive of the motor 3x is controlled.

The above "second case where the current value of the current of the motor 3x is less than the switching threshold current 45 or the frequency of the current flowing through the motor 3x is the switching threshold frequency 46 or more" is referred to as "the phase current flowing through the motor 3x". It may be replaced with "the second case where the value is less than the switching threshold current or the rotation speed of the motor 3x is equal to or more than the switching threshold rotation speed".

In the second case described above, since the motor 3 is driven at a low current or a high frequency, the temperature detected by the thermistor S can sufficiently follow the actual temperature of the heat source Z. In such a case, the power conversion unit 30c controls the drive of the motor 3x while executing the temperature protection function based on the actual thermistor temperature detected by the thermistor S. This makes it possible to prevent damage to the power conversion unit 30c having a heat source.

Here, as shown in FIG. 8, the estimated temperature for control and the actual thermistor temperature detected by the thermistor S may be switched so as to have a hysteresis characteristic.

Specifically, in the control unit 10a, the frequency of the current flowing through the motor 3x is less than the switching threshold frequency 46, and the current value of the current of the motor 3x is smaller than the switching threshold current 45 from the switching threshold current 45 or more. When the current is reduced to the set hysteresis threshold current 49, that is, when the transition is made from the first case to the second case as shown by the arrow 41, the power conversion unit is continuously based on the estimated control temperature. 30 controls the drive of the motor 3 (see FIG. 8).

In addition, the above-mentioned "frequency of the current flowing through the motor 3x is less than the switching threshold frequency 46, and the current value flowing through the motor 3x is smaller than the switching threshold current 45 from the switching threshold current 45 or more, which is a preset hysteresis threshold. "The current drops to 49" is preset so that "the rotation speed of the motor 3x is less than the switching threshold rotation speed and the phase current value of the phase current of the motor 3x is smaller than the switching threshold current from the switching threshold current or more". It may be replaced with "reduces to the hysteresis threshold current".

When transitioning from the first case to the second case as shown by the arrow 41, it takes time for the temperature to converge, so that the detected temperature of the thermistor S cannot sufficiently follow the temperature of the heat source Z. be. In this case, the power conversion unit 30c controls the drive of the motor 3x while executing the temperature protection function based on the above estimated temperature for control. This makes it possible to prevent damage to the power conversion unit 30c having a heat source.

On the other hand, in the control unit 10a, the frequency of the current flowing through the motor 3x is less than the switching threshold frequency 46, and the current value of the current of the motor 3x rises from the hysteresis threshold current 49 or less to the switching threshold current 45, that is. When transitioning from the second case to the first case as shown by the arrow 42, the power conversion unit 30 continuously controls the drive of the motor 3 based on the actual thermista temperature (actual temperature) 50. (See FIG. 8).

The above-mentioned "the frequency of the current flowing through the motor 3x is less than the switching threshold frequency 46, and the current value of the current of the motor 3x rises from the hysteresis threshold current 49 or less to the switching threshold current 45" is described in "Motor 3x". The number of rotations of the motor 3x is less than the switching threshold current, and the phase current value of the phase current of the motor 3x rises from less than the hysteresis threshold current to the switching threshold current. "

When the transition from the second case to the first case is performed as shown by the arrow 42, the temperature rises rapidly, so that the detected temperature of the thermistor S can sufficiently follow the temperature of the heat source Z. In this case, the power conversion unit 30c controls the drive of the motor 3x while executing the temperature protection function based on the above-mentioned actual thermistor temperature. This makes it possible to prevent damage to the power conversion unit 30c having a heat source.

Further, in the control unit 10a, the current value of the current of the motor 3x is set to be equal to or higher than the switching threshold current 45, and the frequency of the current flowing through the motor 3x is set in advance from less than the switching threshold frequency 46 to higher than the switching threshold frequency 46. When the transition is made so as to rise to the hysteresis threshold frequency 48, that is, from the first case to the second case as shown by the arrow 43, the power conversion unit 30 continuously bases the estimated control temperature. , Controls the drive of the motor 3 (see FIG. 8).

It should be noted that the above-mentioned "preset hysteresis in which the current value of the current of the motor 3x is equal to or more than the switching threshold current 45 and the frequency of the current flowing through the motor 3x is lower than the switching threshold frequency 46 and higher than the switching threshold frequency 46". "Increases to the threshold frequency 48", "the phase current value of the phase current of the motor 3x is equal to or higher than the switching threshold current, and the rotation speed of the motor 3x is lower than the switching threshold rotation number to higher than the switching threshold rotation number." It may be replaced with "rises up to the set hysteresis threshold rotation number".

When transitioning from the first case to the second case as shown by the arrow 43, it takes time for the temperature to converge, so that the detected temperature of the thermistor S cannot sufficiently follow the temperature of the heat source Z. be. In this case, the power conversion unit 30c controls the drive of the motor 3x while executing the temperature protection function based on the above estimated temperature for control. This makes it possible to prevent damage to the power conversion unit 30c having a heat source.

On the other hand, the control unit 10a so that the current value of the current of the motor 3x is the switching threshold current 45 or more, and the frequency of the current flowing through the motor 3 decreases from the hysteresis threshold frequency 48 or more to the switching threshold frequency 46, that is. When transitioning from the second case to the first case as shown by the arrow 44, the power conversion unit 30 continuously controls the drive of the motor 3 based on the actual thermista temperature (actual temperature) 50. (See FIG. 8).
The above-mentioned "the current value of the current of the motor 3x is the switching threshold current 45 or more, and the frequency of the current flowing through the motor 3 decreases from the hysteresis threshold frequency 48 or more to the switching threshold frequency 46" is described in "Motor 3x". The phase current value of the phase current of the above is equal to or higher than the switching threshold current, and the rotation speed of the motor 3x decreases from the hysteresis threshold rotation speed or higher to the switching threshold rotation speed. ”

When the transition from the second case to the first case is performed as shown by the arrow 44, the temperature rises rapidly, so that the detected temperature of the thermistor S can sufficiently follow the temperature of the heat source Z. In this case, the power conversion unit 30c controls the drive of the motor 3x while executing the temperature protection function based on the above-mentioned actual thermistor temperature. This makes it possible to prevent damage to the power conversion unit 30c having a heat source.

(Third embodiment)
In the second embodiment described above, the case where the heat source Z is a transistor of the bridge circuit X of the power conversion unit 30c has been described. However, it is also assumed that the heat source Z is a coil of the motor 3x. Therefore, a third embodiment in which the heat source Z is a coil of the motor 3x will be described with reference to FIG. The third embodiment is the same as the second embodiment except that the heat source Z is a coil of the motor 3x.

As shown in FIG. 9, the heat source Z is the coils L1, L2, and L3 of the motor 3x. In the example of FIG. 9, the transistors Q1 to Q6 of the driver circuit X are also described as the heat source Z, as in the second embodiment.

The thermistor S is arranged close to the coils L1, L2, and L3. That is, the first thermistor S1a is arranged close to the coil L1 which is a heat source. The second thermistor S2a is arranged close to the coil L2 which is a heat source. The third thermistor S3a is arranged close to the coil L3 which is a heat source.

In the present embodiment, for example, the temperature value of the first phase coil of the motor 3x is the temperature detection value of the second thermistor Sa2 arranged in the vicinity of the second phase coil of the motor 3x, and the motor. An average value with the detected value of the temperature of the third thermistor Sa3 arranged in the vicinity of the coil of the third phase of 3x may be substituted.

As a result, the first thermistor Sa1 can be omitted.

Further, in the present embodiment, if necessary, the higher temperature of the actual thermistor temperature detected by the above-mentioned thermistor S and the estimated control temperature may be selected for driving the motor. ..

According to this embodiment, in consideration of the influence of heat conduction and ambient temperature, the heat source (power conversion unit (inverter circuit) transistor or motor The temperature of the coil) can be estimated to perform the temperature protection function.

1 Control device 2 Current source 3 Drive unit 5 Input unit 8 Load 10 Control unit 11 Temperature detection unit 20 Storage unit 30 Power conversion unit

Claims (14)

The drive unit that drives the load and
A power conversion unit that converts power from a current source and supplies power to the drive unit,
A temperature detection unit that detects the temperature in the vicinity of the heat source that generates heat in the power conversion unit or the drive unit, and
A control unit that controls the power conversion unit so that the drive unit outputs a command signal input from the torque input unit and a torque determined by the temperature obtained based on the detection result of the temperature detection unit. When,
Equipped with
The control unit
When the temperature obtained based on the detection result is in a restricted state equal to or higher than a preset limit threshold value and lower than a preset abnormal threshold value higher than the limit threshold value, a command corresponding to the command signal is given. A drive device characterized in that the power conversion unit is controlled so that a limit torque smaller than the torque is output from the drive unit. The control unit
When the temperature obtained based on the detection result is equal to or higher than the abnormality threshold value, the power conversion unit is controlled so that the torque output from the drive unit becomes zero. The drive device according to claim 1. The control unit
When the temperature obtained based on the detection result is in a normal state below the limit threshold value, the power conversion unit is controlled so that the command torque corresponding to the command signal is output from the drive unit. The driving device according to claim 1 or 2. It is further provided with a storage unit that stores a target limit torque table in which the frequency of the current flowing through the drive unit and the target limit torque are associated with each other when the temperature obtained based on the detection result is the limit threshold. The drive device according to any one of claims 1 to 3. In the restricted state, the control unit is
The frequency of the current flowing through the drive unit is acquired, and the frequency is obtained.
The fourth aspect of the present invention is characterized in that the limit torque is set so as to be equal to or larger than the magnitude of the target limit torque corresponding to the acquired frequency with reference to the target limit torque table stored in the storage unit. The drive device described. In the restricted state, the control unit is
A temperature difference value is calculated by integrating a positive adjustment coefficient into a value obtained by subtracting the limiting threshold value from the temperature obtained based on the detection result.
The frequency of the current flowing through the drive unit is acquired, and the frequency is obtained.
With reference to the target limit torque table stored in the storage unit, the target limit torque corresponding to the acquired frequency is calculated.
By adding the temperature difference value to the value obtained by subtracting the current torque currently output by the drive unit from the calculated target limit torque, a negative cut torque to be subtracted from the command torque is calculated. ,
The limit torque is calculated by adding the negative cut torque to the command torque.
The drive device according to claim 4, wherein the power conversion unit is controlled so that the limit torque is output from the drive unit. In the target limiting torque table, the target limiting torque is set to increase as the frequency of the current flowing through the drive unit increases, and the target limiting torque decreases as the frequency of the current flowing through the drive unit decreases. The drive device according to any one of claims 4 to 6, wherein the drive device is characterized by that. The temperature obtained based on the detection result is the estimated control temperature obtained by the control unit.
The storage unit stores a saturation temperature information table that associates a combination of the current value flowing through the drive unit and the frequency of the current flowing through the drive unit with the saturation temperature, which is the maximum temperature at which the heat of the heat source saturates. And
The control unit
The current value flowing through the drive unit is acquired, and the frequency of the current flowing through the drive unit is acquired.
With reference to the saturation temperature information table stored in the storage unit, step a for calculating the current saturation temperature of the heat source corresponding to the combination of the current value and the frequency, and
Step c to calculate the current estimated heat source temperature by estimating the temperature of the heat source by using the current saturation temperature and the first coefficient, and
Step e to calculate the current estimated detection unit temperature that estimates the temperature in the vicinity of the heat source by using the current estimated heat source temperature and the second coefficient.
Step f to acquire the actual temperature detected by the temperature detection unit, and
The g step of calculating the temperature difference by subtracting the actual temperature from the current estimated detection unit temperature,
The h step of calculating the temperature correction value by multiplying the temperature difference by a preset temperature correction coefficient, and
It has a function to execute the i-step of calculating the estimated temperature for control by adding the temperature correction value to the current estimated heat source temperature.
The current estimated heat source temperature in step c is
When the current saturation temperature is equal to or higher than the past estimated heat source temperature, and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is equal to or higher than the first P threshold, the first coefficient is used. Calculated by the following formula 31 with 1P coefficient.
When the current saturation temperature is equal to or higher than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is less than the first P threshold, the first coefficient. Is the second P coefficient smaller than the first P coefficient, and is calculated by the following equation 32.
When the current saturation temperature is lower than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is equal to or less than the first N threshold, the first coefficient is used. Calculated by the following formula 33 with a 1N coefficient.
When the current saturation temperature is lower than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current saturation temperature is larger than the first N threshold, the first coefficient is used. The second N coefficient is smaller than the first N coefficient, and it is calculated by the following formula 34.
The past estimated heat source temperature is a temperature calculated by the same calculation method as the current estimated heat source temperature before the first time.
The current estimated detection unit temperature in the e step is
When the current estimated heat source temperature is higher than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is equal to or larger than the second P threshold, the second coefficient is used. Calculated by the following formula 41 as the 3rd P coefficient.
When the current estimated heat source temperature is higher than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is less than the second P threshold, the second coefficient Is the 4th P coefficient smaller than the 3rd P coefficient, and is calculated by the following equation 42.
The second coefficient is when the current estimated heat source temperature is equal to or lower than the past estimated heat source temperature and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is equal to or less than the second N threshold. Is the 3rd N coefficient, and it is calculated by the following formula 43.
If the current estimated heat source temperature is equal to or lower than the past estimated heat source temperature, and the temperature difference obtained by subtracting the past estimated heat source temperature from the current estimated heat source temperature is larger than the second N threshold, the second coefficient is used. It is calculated by the following equation 44 with the 4N coefficient smaller than the 3N coefficient.
One of claims 4 to 7, wherein the past estimated detection unit temperature is a temperature calculated by the same calculation method as the current estimation detection unit temperature calculation method before the first time. The drive device described in.
Current estimated heat source temperature = 1st P coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 31)
Current estimated heat source temperature = 2nd P coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 32)
Current estimated heat source temperature = 1st N coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 33)
Current estimated heat source temperature = 2nd N coefficient × (current saturation temperature-past estimated heat source temperature) + past estimated heat source temperature ... (Equation 34)
Current estimated detector temperature = 3rd P coefficient × (current estimated heat source temperature-past estimated detector temperature) + past estimated detector temperature ... (Equation 41)
Current estimated detection unit temperature = 4th P coefficient × (current estimated heat source temperature-past estimated detection unit temperature) + past estimated detection unit temperature ... (Equation 42)
Current estimated detector temperature = 3N coefficient × (current estimated heat source temperature-past estimated detector temperature) + past estimated detector temperature ... (Equation 43)
Current estimated detection unit temperature = 4th N coefficient × (current estimated heat source temperature-past estimated detection unit temperature) + past estimated detection unit temperature ... (Equation 44) The a step, the c step, the e step, and the i step are repeated every first time.
The control device according to claim 8, wherein the f step, the g step, and the h step are repeated every second time longer than the first time. The control device according to claim 8 or 9, wherein the first coefficient is a value greater than 0 and less than 1, and the second coefficient is a value greater than 0 and less than 1. The control unit
When the current value flowing through the drive unit is less than the preset switching threshold current, or the frequency of the current flowing through the drive unit is equal to or higher than the preset switching threshold frequency, it is obtained based on the detection result. The driving device according to any one of claims 8 to 10, wherein the temperature is not the estimated temperature for control but the actual temperature detected by the temperature detecting unit. When the temperature obtained based on the detection result becomes equal to or higher than the abnormal threshold value, the control unit stops the drive unit and then resets the operation of the control unit until the operation of the control unit is reset. The drive device according to any one of claims 1 to 11, wherein the control of the above is not resumed. In a control method that controls a power conversion unit that converts power from a current source and supplies power to the drive unit.
The temperature obtained based on the detection result by the temperature detection unit arranged in the vicinity of the heat source that generates heat in the power conversion unit or the drive unit is equal to or higher than a preset limit threshold value and higher than the limit threshold value in advance. When the limit state is less than the set abnormal threshold value, the power conversion unit is controlled so that the drive unit outputs a limit torque smaller than the command torque corresponding to the command signal input from the torque input unit. A control method characterized by that. The control unit
When the temperature obtained based on the detection result is equal to or higher than the abnormality threshold value, the power conversion unit is controlled so that the torque output from the drive unit becomes zero. The control method according to claim 13.

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