JPH08214402A - Protective device and control method of motor car - Google Patents

Abstract

PURPOSE: To provide a protective device capable of preventing failure owing to the erroneous control of a driving motor and an inverter owing to the disconnection of a temperature sensor in a motor car by deciding the disconnection of the temperature sensor without mounting a circuit for detecting the disconnection. CONSTITUTION: A protective device for a motor car has a signal generating means 5 for receiving the command value of a torque command means 1 and generating a control signal, an inverter 6 for receiving the signal of the signal generating means and driving a motor 3, and temperature detecting means 8-11, 16 for detecting the temperatures of the motor and the inverter, and the signal generating means is controlled in response to outputs from the temperature detecting means and the motor and the inverter are protected so as not to reach a high temperature. A motor- temperature sensor short-circuit disconnection decision section 5A and an inverter- temperature sensor short-circuit disconnection decision section 5B are provided, the temperature detecting means under the state of a short circuit and disconnection are decided, when outputs from the temperature detecting means reach a set value or more at a high temperature, where normal operation cannot reach, and a temporary value is substituted for outputs from the temperature detecting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective device for an electric vehicle, and more particularly to a protective device and a control method for coping with a failure of a temperature detecting sensor of the electric vehicle.

[0002]

2. Description of the Related Art In recent years, an electric motor of vector control type has been widely used in order to use an induction motor driven by an inverter for vehicle propulsion and to control the induction motor at high speed and with high accuracy. Generally, an electric vehicle includes an inverter that converts a DC power source of a battery into an AC power source of a variable voltage and a variable frequency, a three-phase AC motor for driving a vehicle, a current sensor that detects a current and a rotation speed of the three-phase AC motor, and A speed sensor, a torque command calculation means for determining a torque command of the three-phase AC motor according to the accelerator opening, and a phase current flowing through a winding of the three-phase AC motor based on the torque command and the output of the current sensor. Three-phase AC current command generating means for generating a three-phase AC current command for controlling, and applied to the gate of the inverter based on the three-phase AC current command and the phase current flowing in the winding of the three-phase AC motor. A signal generating means for generating a signal for

In such an electric vehicle, the conventional apparatus is disclosed in Japanese Unexamined Patent Publication No. 4-145802, page 2, upper right column, line 12 to page 3, lower left column, line 5, as shown in FIG. Is measured by a temperature sensor, and when the temperature data indicating that the electric motor or the like is overheated is abnormal, the change progress of the operating temperature is predicted based on the detected value in the past certain period or its integrated value and used for vector control. Further, as described in the above-mentioned known example, page 3, upper right column, lines 4 to 13,
When the temperature data shows 0 or infinity and is out of the measurement range, an abnormality in the temperature detection system is detected.

As for the abnormality of the sensors other than the temperature sensor, Japanese Patent Laid-Open No. 5-91601 discloses a technique of switching the control method from vector control to v / f control when the rotation sensor is abnormal. JP-A-4-252
Japanese Patent Publication No. 775 discloses a technique in which the auxiliary steering torque sensor controls the steering angle when the torque sensor is abnormal. Japanese Unexamined Patent Publication No. 61-46188 discloses a technique of limiting the detected value of the rotation speed within the range of the upper and lower limit detectors.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the conventional technique disclosed in Japanese Patent No. 802, the operating temperature cannot be predicted when the temperature detection system has an abnormality from the beginning. Further, in the case of a temperature sensor used for protecting a drive motor of a drive control device for an electric vehicle and an inverter, the operating point is at a high temperature exceeding 100 ° C., and therefore, the circuit is configured to easily detect the high temperature. When a thermistor is used as the temperature sensor, the electric resistance changes logarithmically. Therefore, in the above circuit configuration, there is only a slight difference in the temperature data between when the temperature is low in winter and when the temperature sensor is abnormal, for example, the wire is disconnected. Therefore, considering the variations in the temperature sensor and the circuit, there is a drawback that the disconnection of the temperature sensor cannot be detected accurately. Also, the coil temperature is 2
When the temperature rises above 20 ° C., the inverter is stopped to prevent deterioration of the insulating material. At this time, if the temperature sensor is short-circuited, it is detected that the coil temperature is high even though the coil temperature is low.If the temperature protection is activated by the output value, the high temperature protection will work and the inverter will be stopped. The car cannot run.

An object of the present invention is to accurately determine the disconnection of a temperature sensor without providing a circuit for detecting disconnection,
It is an object of the present invention to provide a protection device and a control method capable of preventing damage due to erroneous control of a drive motor or an inverter due to a break in a temperature sensor in an electric vehicle.

Another object of the present invention is to provide a protective device and a control method capable of safely controlling an electric motor or an inverter while the output value is limited without using the output value of the temperature sensor which is short-circuited. Especially.

[0008]

In order to achieve the above object, the present invention provides an electric motor using a battery as a power source and a torque command means for calculating a torque command value of the electric motor at least by receiving an output signal of an accelerator. A signal generating means for receiving a command value of the torque commanding means to generate a control signal; an inverter for driving the electric motor in response to the signal of the signal generating means; and a temperature for detecting the temperature of the electric motor and the inverter. In a protection device for an electric vehicle that includes a detection unit and controls the signal generation unit according to the output of the temperature detection unit to protect the electric motor and the inverter from becoming high temperature, the output of the temperature detection unit is usually When a value corresponding to a high temperature that is impossible in the operation of is set as a set value, and the output value of the temperature detecting means is equal to or more than the set value,
It is characterized in that the temperature detecting means is judged to be in a short-circuit disconnection state, and the output of the temperature detecting means is substituted by a provisional value.

[0009]

According to the present invention, when the output of the temperature detecting means exceeds a high temperature set value which is not possible in normal operation, for example, 260 ° C. or more, it is determined that the temperature detecting means is in a short circuit disconnection state, The output of the temperature detecting means is substituted by the provisional value, and the control of the electric motor and the inverter is continued. As a result, it is possible to provide a protection device capable of preventing damage due to erroneous control of the drive motor and the inverter due to the disconnection of the temperature sensor in the electric vehicle. Further, it becomes possible to control the minimum necessary electric motor by limiting the output value of the temperature sensor which is short-circuited.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a drive control device for an electric vehicle according to an embodiment of the present invention. The torque command device 1 receives the electric signal of the potentiometer that changes according to the amount of depression of the accelerator 2 and the electric signal of the rotation speed sensor 4 that detects the rotation speed of the electric motor 3, and calculates and outputs a torque command value. . The signal generator 5 uses the PW to generate the torque of the command value.
The M control signal is output, and the PWM control signal causes the inverter 6 to convert the electric power supplied from the battery 7 into an alternating current and apply it to the electric motor 3.

Each of the motor 3 and the inverter 6 is provided with two thermistor temperature sensors 8, 9, 10, 11 respectively, and the outputs of these are input to the signal generator 5.
It is used to monitor the overheat condition of the electric motor 3 and the inverter 6. For example, when the coil temperature is 220 ° C. or higher, the signal generator 5 stops the inverter 6 in order to prevent deterioration of the insulating material.

Further, in order to detect the circulation condition, the electric signal of the outside air temperature sensor 13 of the air conditioner controller (indoor air conditioner) 12 is also input to the signal generator 5.

In order to cool the electric motor 3 and the inverter 6, cooling water is circulated by the circulation pump 14 and radiated by the radiator 15. A thermistor temperature sensor 16 is provided in the cooling water pipe to cool the cooling fan 1 when the water temperature rises.
Operate 7 to help radiate heat.

The signal generator 5 is provided with an electric motor temperature sensor short circuit disconnection determination unit 5A and an inverter temperature sensor short circuit disconnection determination unit 5B. The motor temperature sensor short circuit disconnection determination unit 5A determines whether the temperature sensor of the motor has a short circuit disconnection. When the temperature sensor of the electric motor is abnormal, the output is limited and the electric motor is controlled to drive the electric vehicle so that the temperature does not rise. As described above, when it is determined that the temperature sensor is short-circuited or disconnected, control is performed such that the electric vehicle is run while limiting the output so that the electric motor does not become hot.

Inverter temperature sensor short circuit disconnection determination unit 5B
Determines whether the temperature sensor of the inverter is short-circuited or broken. Even when the temperature sensor of the inverter is abnormal, the output is limited so that the temperature of the inverter does not rise, and the inverter is controlled to drive the electric vehicle.

The thermistor temperature sensor 10 provided in the electric motor 3 is a temperature sensor provided in the coil portion of the electric motor and detects the temperature TM1 of the coil portion. Also, the electric motor 3
Another thermistor temperature sensor 11 provided in is a rotor temperature sensor provided near the motor rotor, and its output is used for secondary resistance correction of the motor winding.

FIG. 2 is a flow of software stored in the memory of the microcomputer constituting the signal generator 5, which is activated every 2 milliseconds. The numbers in the flow are step numbers.

In the temperature detection process (step 20), the output signals of the temperature sensors 8, 9, 10, 11, 16 and the outside air temperature sensor 13 are input to the signal generator 5 and converted into temperature data. Next, it is determined whether or not the signal system of each temperature sensor is short-circuited in a short circuit disconnection determination process (step 30) shown in detail in FIG. As described above, the electric vehicle can run even if the temperature sensor of the electric motor is abnormal, so the electric motor is controlled by limiting the output so as not to reach a high temperature.

The temperature = resistance characteristic of the temperature sensor is as follows. R = R ₀ exp {B × (1 / (T + 273.15) −1 /
(T ₀ +273.15))} where R, R ₀ : electrical resistance, T, T ₀ : temperature, B: constant When the temperature sensor is short-circuited, the resistance R is small and is output as a detected value from the relationship of the above equation. The temperature T that is applied increases. When a voltage equivalent to a high temperature, which is not normally possible, for example, 0.204V is detected, it can be determined that the temperature sensor is short-circuited.

In the torque command input process, the torque command value calculated by the torque command device 1 is received by the serial communication interface (step 40).

In the target torque limiting process (step 50) shown in detail in FIG. 5, the torque is limited as necessary to protect the electric motor 3 and the inverter 6.

In the next electric motor control process (step 60), electric motor control for supplying three-phase alternating current to the electric motor 3 so as to obtain the target torque is performed. Among these, in order to correct the secondary resistance of the winding of the electric motor 3, the electric motor temperature TM detected by the temperature sensors 10 and 11 and determined by the temperature detection (step 20) is used. Finally, in the cooling fan control process (step 70) shown in detail in FIG. 6, the cooling fan 17 is controlled, and the series of controls is ended.

FIG. 3 is a detailed flow chart of the short circuit disconnection determination process (step 30) of the electric motor temperature sensor shown in FIG. The first detection voltage VM1 corresponding to the detection temperature TM1 of the temperature sensor 10 attached to the coil portion of the electric motor 3 is changed to the voltage VML (= 10 ° C. in the present embodiment) of the determination temperature TML (= 10 ° C.).
4.04 V). When the result is true, that is, when the first detected voltage VM1 is higher than the voltage VML, the second detected voltage VM2 corresponding to the detected temperature TM2 of the temperature sensor 11 of the rotor is further compared with the voltage VML, and the result is If true, it is determined that the temperature sensor of the coil portion and the temperature sensor 11 of the rotor are at a low temperature, and the secondary resistance correction and temperature protection are substituted by the voltage VML (corresponding to 10 ° C.).

If the result of comparison between the second detection voltage VM2 and the disconnection determination voltage VML is false, the second detection voltage VM2 is not the normal determination temperature TMH (260 in this embodiment).
C.) and the voltage VMH (= 2.04V) corresponding to the voltage. If the result is true, the temperature sensor 11 of the rotor is determined to be abnormal, and the secondary resistance correction and temperature protection are performed by the voltage VML (10 ° C
Equivalent) and write it to the memory and display it on the fault monitor. If the result of the comparison is false, it is checked whether the temperature TM2 detected by the temperature sensor 11 of the rotor is 50 ° C. or higher. If the temperature is 50 ° C. or higher, the temperature sensor 10 determines that the disconnection is abnormal and writes the error in the memory. Display on the monitor.

The value of 50 ° C. is the judgment temperature TML.
(10 ° C. in this embodiment) is the value obtained by adding the difference between the temperatures normally detected by both sensors, that is, TM1-TM2. Regardless of the value of the detected temperature TM2 of the rotor temperature sensor 11, the secondary resistance correction and temperature protection are performed by the detected temperature TM2 of the temperature sensor 11.
Control using.

If the comparison result of the first detection voltage VM1 corresponding to the detection temperature TM1 of the temperature sensor 10 and the voltage VML (= 4.04V) is false, the second detection voltage VM2 and the voltage V2 are further detected.
ML is compared, and if the result is true, the first detection voltage VM1
And the voltage VMH (= 2.04V) are compared. When the result is true, it is determined that the temperature sensor 10 is short-circuited, the error is displayed on the monitor, and the secondary resistance correction and the temperature protection are substituted by the voltage VML (= 4.04 V). If the result of comparison between the first detection voltage VM1 and the voltage VMH is false, it is checked whether the detection temperature TM1 of the temperature sensor 10 is 50 ° C. or higher, and if it is 50 ° C. or higher, the temperature sensor 11 is determined to be a disconnection abnormality. Then, write it to the memory and display it on the fault monitor. Regardless of the temperature detected by the temperature sensor 10, the secondary resistance correction and temperature protection are controlled by using the detected temperature TM1 of the temperature sensor 10.

The detected temperatures TM1 and TM2 are compared, and if the result is true, the first detected voltage VM1 and the voltage VMH (= 2.0).
4V), and if the first detection voltage VM1 is small, the temperature sensor 10 is determined to be abnormal, and secondary resistance correction and temperature protection are performed using the output of the temperature sensor 11. On the contrary, when the first detection voltage VM1 is large, both the temperature sensor 10 and the temperature sensor 11 are determined to be normal, and the secondary resistance correction is controlled by using TM2 and the temperature protection is controlled by using TM1.

When the result of comparison between the detected temperatures TM1 and TM2 is false, the second detected voltage VM2 and the voltage VMH (= 2.04V) are compared, and when the second detected voltage VM2 is small, the temperature sensor 11 operates. It is determined to be abnormal, and control is performed using the output TM1 of the temperature sensor 10. On the contrary, when the first detection voltage VM1 is small, the output TM2 of the temperature sensor 11 is used for control.

FIG. 4 is a detailed flow of the short circuit disconnection determination processing of the thermistor temperature sensor attached to the inverter 6. Thermistor temperature sensor 8 attached to the inverter 6
The detected temperature TI1 and the determination temperature TIL on the low temperature side (10 ° C. in this embodiment) are compared, and if true, the thermistor temperature sensor 8 is short-circuited, the protection function is stopped, and it is used for controlling the motor. If the temperature is 60 ° C. or higher, it is determined that the inverter temperature sensor is broken. This is because when the temperature of the electric motor is 60 ° C. or higher, it is considered that the inverter temperature should also be rising.

In the case of false, the detected temperature TI1 of the thermistor temperature sensor 8 is compared with the judgment temperature TIH (200 ° C. in this embodiment) on the high temperature side which cannot be normally taken, and in the case of true, the inverter temperature sensor is short-circuited. The protection function is stopped. If false, the inverter temperature sensor is assumed to be normal and the temperature is protected by TM1.

FIG. 5 is a detailed flow of the target torque limiting process of FIG. The detected temperature TM of the electric motor is compared with the temperature TMC for limiting the torque command of the electric motor (step 13
0), if false, the inverter temperature TI is compared with the temperature TIC for limiting the torque command (step 131). If the result of the comparison of these (steps 130, 131) is true, the torque command value Trq received from the torque command device is compared with the maximum torque value TrqC when the sensor is abnormal (step 132). The command value Trq is limited to the maximum torque value TrqC (step 133).

FIG. 6 is a detailed flow of the cooling fan control process of FIG. Temperature TW detected by the thermistor temperature sensor 16 provided in the cooling water pipe and temperature TWf requiring air cooling
(60 ° C. in this embodiment) is compared (step 140),
If true, turn on the cooling fan, (step 14
1) If false, stop the cooling fan (step 142).

[0033]

According to the present invention, the breakage of the temperature sensor in the electric vehicle is determined without providing a special circuit for detecting the breakage, and the breakage of the drive motor or the inverter due to the breakage of the temperature sensor in the electric vehicle is damaged. It is possible to provide a protection device capable of preventing the above.

Further, it is possible to provide a protection device in which the output value of the short-circuited temperature sensor is limited and the motor can be controlled.

[Brief description of drawings]

FIG. 1 is a diagram showing a drive control device for an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a software flow chart of the microcomputer of the signal generator of FIG.

FIG. 3 is a detailed flowchart of a short circuit / open circuit detection process of the electric motor temperature sensor of FIG.

FIG. 4 is a detailed flow chart of the inverter temperature sensor short circuit and disconnection detection processing of FIG.

5 is a detailed flowchart of the target torque limiting process of FIG.

FIG. 6 is a detailed flowchart of the cooling fan control process of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Torque command device, 2 ... Accelerator, 3 ... Electric motor (electric motor), 4 ... Rotation speed sensor, 5 ... Signal generator, 6 ... Inverter, 7 ... Battery, 8, 9, 10, 11, 16 ... Thermistor temperature sensor , 12 ... Air conditioner control device (indoor air conditioner), 13 ... Outside air temperature sensor, 14 ... Circulation pump, 15 ... Ragetor, 17 ... Cooling fan

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shotaro Naito 2520, Takaba, Hitachinaka City, Ibaraki Pref., Ltd. Automotive Equipment Division, Hitachi, Ltd. (72) Nobuki Matsudaira 2520, Takaba, Hitachinaka City, Ibaraki Prefecture Ceremony Company Hitachi, Ltd. Automotive Equipment Division (72) Inventor Sanshiro Ohara 2520, Takaba, Hitachinaka City, Ibaraki Prefecture Stock Company Hitachi Ltd. Automotive Equipment Division (72) Inventor Shigeyuki Yoshihara Kajima, Hitachinaka City, Ibaraki Prefecture Yatsu 2477 3 Hitachi Automotive Engineering Co., Ltd. (72) Inventor Hiroyuki Yamada Kashima Yatsu 2477 3 Hitachi Automotive Engineering Ring Co., Ltd. Hirotaka Yamada Ibaraki

Claims (4)

[Claims] 1. A battery-powered electric motor, a torque command means for calculating a torque command value of the motor by receiving at least an output signal of an accelerator, and a control signal generated by receiving a command value of the torque command means. Signal generating means, and an inverter that receives the control signal and drives the electric motor,
A protection device for an electric vehicle, comprising: temperature detection means for detecting temperatures of the electric motor and the inverter, and controlling the signal generation means in accordance with an output of the temperature detection means to prevent overheating of the electric motor and the inverter. In the above, as the output value of the temperature detecting means, a value corresponding to a high temperature that is not possible in normal operation is set as a set value, and when the output value of the temperature detecting means becomes equal to or more than the set value, the temperature detection is performed. A means for protecting the electric vehicle is characterized in that the means determines that there is a short circuit disconnection state, and substitutes the output of the temperature detecting means with a provisional value. 2. When the temperature detecting means of the electric motor is judged to be in a short circuit disconnection state according to claim 1, the output of the temperature detecting means is replaced with a provisional value so that the output of the electric motor is kept below a predetermined value. A protective device for an electric vehicle, characterized in that the vehicle is allowed to continue traveling while being limited. 3. When the temperature detecting means of the inverter is determined to be in a short circuit open state according to claim 1, the output of the temperature detecting means is replaced with a provisional value so that the control by the inverter is continued. An electric vehicle protection device characterized by the following. 4. An electric motor using a battery as a power source, a torque command means for calculating a torque command value of the motor by receiving at least an output signal of an accelerator, and a control signal generated by receiving a command value of the torque command means. Signal generating means, and an inverter that receives the control signal and drives the electric motor,
A method of controlling an electric vehicle, comprising: a temperature detection unit that detects temperatures of the electric motor and the inverter; and controlling the signal generation unit according to an output of the temperature detection unit to prevent overheating of the electric motor and the inverter. In the above, as the output value of the temperature detecting means, a value corresponding to a high temperature that is not possible in normal operation is set as a set value, and when the output value of the temperature detecting means becomes equal to or more than the set value, the temperature detection is performed. A means for controlling the electric vehicle is characterized in that the means determines that there is a short circuit disconnection state, and substitutes the output of the temperature detecting means with a provisional value.