JPH07264701A - Trouble detector for electric railcar and protective device using the same - Google Patents

Abstract

PURPOSE:To provide a trouble detecting method for an electric railcar which can early and easily detect a malfunction of a control system and a protective device using the same. CONSTITUTION:The trouble detector for an electric railcar having a controller 5 for generating a signal to be applied to a gate of an inverter 3 based on three-phase AC current commands and phase currents flowing to windings of a three-phase AC motor 4 detects malfunctions of the controller 5 and a speed sensor 6 based on a direction of a phase rotation of the three-phase AC current to be detected by a phase sequence detector 52, a command of FR command means 9 and an opening of an accelerator 8. The malfunction of the controller, etc., is detected by phase sequence detection of whether phases (u), (v), (w) of the three-phase ACs are present as normal sequence or not. For example, when the sequence of v-phase and w-phase becomes reverse to the normal sequence, a sequence is judged. Further, when the controller 5, the sensor 6, etc., are abnormal, drive of the motor is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle failure detection device and a protective device using the same, and more particularly to an electric vehicle protective device suitable for an electric vehicle driven by an AC electric motor using a battery as a power source. .

[0002]

2. Description of the Related Art Generally, an electric vehicle includes an inverter for converting a DC power source of a battery into an AC power source of variable voltage and variable frequency, a three-phase AC motor for driving a vehicle, a three-phase AC motor and a drive shaft of the vehicle. FR command means for controlling a connecting portion for connecting the positive and negative sides, a current sensor and a speed sensor for detecting a current and a rotation speed of the three-phase AC motor, and a torque command for the three-phase AC motor according to an accelerator opening. And a three-phase AC current command for generating a three-phase AC current command for controlling the phase current flowing in the winding of the three-phase AC motor based on the torque command and the output of the current sensor. And a signal generating means for generating a signal to be 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.

In such an electric vehicle, a torque control system is based on a torque command issued by a driver through an accelerator opening, a motor current detected by a current sensor, and a motor rotation angular velocity detected by a speed sensor. Are configured. In order to ensure the safety of such a torque control system, as disclosed in Japanese Patent Publication No. 3-277101, the sensors are made into a dual system, and if one sensor fails, the other auxiliary sensor is used. It is known to switch and drive an electric motor based on information obtained from this auxiliary sensor.

[0004]

The reliability of the sensing itself is improved by using a multiple sensor system, but the reliability of the torque control system as a whole is not necessarily increased because the number of cables and connectors for drawing the detected signals increases. It does not always rise. Further, there may be a case where a malfunction occurs in another sensor that should be an auxiliary depending on the cause of the failure, and it may be dangerous depending on how to switch the auxiliary means. Rather, it is desirable that the torque control system failure can be detected reliably at an early stage with a simple configuration.

Among the control system faults of electric vehicles, a fault in which the rotational direction of the electric motor cannot be controlled correctly is particularly dangerous because, for example, a situation in which the vehicle tries to move forward and then moves backward.

It is an object of the present invention to provide a failure detection method for an electric vehicle that can detect an abnormality in a control system of the electric vehicle early and easily, and a protection device using the failure detection method.

Another object of the present invention is to provide a highly reliable method for detecting an abnormality in a control system of an electric vehicle and a protective device using the method.

[0008]

According to the present invention, there is provided an inverter for converting a DC power supply of a battery into an AC power supply of a variable voltage and a variable frequency, a three-phase AC motor for driving a vehicle, and a current of the three-phase AC motor. A current sensor for detecting, a torque command calculation means for determining a torque command of the three-phase AC motor according to an accelerator opening, and a current of the three-phase AC motor based on the torque command and the output of the current sensor. For generating a three-phase AC current command for generating a signal for generating a signal for controlling the inverter based on the three-phase AC current command and the current flowing in the three-phase AC motor In an electric vehicle controller having means, a phase sequence detection circuit for detecting phase rotation of the three-phase alternating current, a shift for controlling output of operation command means and three-phase AC motor phase rotation. Based on the output of the pitch, characterized in that it comprises an abnormality detecting means for detecting an abnormality of the control device.

[0009]

The abnormality detecting means of the control system makes the determination based on the information on the traveling direction of the vehicle and the information on the rotating direction of the electric motor. The traveling direction of the vehicle is determined based on information such as the output of the driving command means (accelerator switch or brake switch) and the output of the shift switch. The rotation direction of the electric motor is
It is determined by phase sequence detection such as whether or not each phase u, v, w in the three-phase alternating current appears in a regular sequence. For example,
Since it is essentially impossible that the order of the v-phase and the w-phase is reversed during normal forward traveling, it is determined that there is an abnormality in either the control device or the inverter.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the block diagram of the control device for an electric vehicle shown in FIG. In FIG. 1, 1 is a battery which is a main power source of an electric car, 2 is a main contactor for opening and closing a main circuit, 3 is an inverter for converting direct current of the battery 1 into alternating current using a power switching element, and 4 is for driving the electric car Electric motor, 5 is a controller, 6
Is an encoder for detecting the rotation speed of the electric motor 4. Further, 7 (7a, 7b, 7c) is a current detector that detects the current of the electric motor 4, and 8 is an accelerator switch that outputs when the accelerator is depressed. The controller 5 detects an abnormality of the encoder 6 in order to perform fail-safe control of the waveform shaping circuit 51, the phase sequence detection circuit 52, the power switching elements (31 to 36) of the inverter 3 and the electric vehicle. It has a traveling abnormality detection circuit 54 for detecting. Reference numeral 9 is a shift switch for changing over between forward and backward movement of the vehicle. That is,
The shift switch 9 controls the direction of phase rotation of the inverter drive circuit 53 to be forward or reverse.

In the controller 5, the inverter 3 converts the direct current power supplied through the battery 1 and the main contactor 2 into alternating current by the drive signal from the inverter drive circuit 53. Then, this AC voltage is supplied to the electric motor 4.

2 and 3 show details of the configuration and operation of the controller 5. Current detector 7 (7a, 7b, 7c)
The three-phase current values Iu, Iv, and Iw detected in 1 are input to the waveform shaping circuit 51. These three-phase current values Iu, Iv, Iw
3 has a waveform as shown in FIG. 3A, which is waveform-shaped by the waveform shaping circuit 51 as rectangular waves u, v, w as shown in FIG.

In the phase sequence detection circuit 52, the waveform shaping circuit 51
It is detected whether or not the respective phases u, v, w in the three-phase alternating current sent from the device appear in a regular order. In FIG. 3B, the solid line indicates a normal state.
If the order of the v-phase and the w-phase is reversed, as indicated by the broken line, the phase-sequence detection circuit 52 judges that it is abnormal and outputs φ.

The running abnormality detection circuit 54 is a phase sequence detection circuit 5.
The presence / absence of a traveling abnormality is detected based on the output φ of 2, the output AC of the accelerator switch 8 and the output F (forward) or R (reverse) of the shift switch 9.

FIG. 4 shows details of the traveling abnormality detection circuit 54. This circuit 54 includes an exclusive OR circuit 541 that receives two inputs of φ and F · R, and an output AC of the accelerator switch 8.
A logic circuit including an amplifier 542 that amplifies the signal, an exclusive OR circuit 541, and an AND gate 543 that receives two inputs of the amplifier 542. The output of the AND gate 543 goes through a timer circuit composed of a resistor 544, a capacitor 545, and a diode 546, and then the gate 54 of the thyristor 547.
8 is connected.

The timer circuit transmits the output of the AND gate 543 to the gate 548 of the thyristor 547 when the output of the AND gate 543 continues for a predetermined time t or longer (for example, 2 to 3 seconds or longer). This distinguishes a normal error from a regular start on a slope. That is, in the case of starting on a slope, even if the torque control system is normal, the vehicle retreats due to its own weight even though the accelerator is stepped on, so the armature of the electric motor 4 temporarily rotates in the reverse direction. This is because u, v, w may be output in a low rotation phase. This thyristor 547 is a transistor switch 5 connected between the relay 20 for opening and closing the main contactor 2 and the power supply.
It is connected to the base of 49. 550 is a key switch.

When the vehicle moves backward on a slope, the driver normally steps on the accelerator harder, so that the driving force exceeds the backward force of the vehicle, and the vehicle moves forward. If the armature of the electric motor 4 continues to rotate in reverse, that is, if the armature of the electric motor 4 does not move forward even after a lapse of a predetermined time t, it is abnormal. In such a case, it is determined that the torque control system is abnormal.

FIG. 5 shows a truth table of the logic circuit of the traveling abnormality detection circuit 54. Input φ of exclusive OR circuit 541
When FR and FR are both 0 or 1, the output is 0, and when one of the inputs is 1 and the other is 0, the output is 1
Becomes

On the other hand, the output AC of the accelerator switch 8 is
It is 1 when the accelerator is depressed and 0 when it is not depressed. When the accelerator switch AC is 1 and the output of the exclusive OR circuit 54 is 1, it is determined to be abnormal. In the case of forward operation, the FR output is 0, the value of φ is 0 when the encoder 6 or the controller is normal, and 1 when there is an abnormality in the encoder or the controller. In this way, the abnormality of the encoder 6 or the controller can be detected.

In the reverse operation, the FR output is 0, the value of φ is 1 if the encoder or the like is normal, and it is 0 if the encoder or the like is abnormal. In this way, the abnormality of the encoder 6 or the controller can be detected.

Even if the encoder and the controller are normal, even if the inverter has an abnormality, the φ output becomes different from that at the normal time, and it can be detected as an abnormality.

When the traveling abnormality detection circuit 54 detects an abnormality in the encoder, controller or inverter, the relay 20 is actuated for safety and the operation of the main circuit is stopped.

The difference between the start on the slope and the start on the flat ground may be detected by incorporating an inclination switch. As shown in FIG. 6, when the output of the EXOR is 1, that is, the output is reversed, even if the output of the tilt switch is 0 on a flat ground, it is determined to be abnormal. If the tilt switch output is 1
In case of, there is a possibility of reversing on the slope and it is not judged as abnormal.

As a method of detecting the rotation direction of the electric motor, instead of the method of detecting the phase current of the electric motor 4 described in the above embodiment, the phase voltage may be detected. In addition, the phase of the drive signal output from the inverter drive circuit 53, the voltage and current on the gates and output sides of the power switching elements (31 to 36) of the inverter are detected, and it is determined whether the order is normal. May be.

Furthermore, instead of the accelerator switch,
The determination may be made in combination with a brake switch.

[0026]

According to the present invention, the abnormality of the control system in the control device for the electric vehicle can be detected early and easily. Also,
It is possible to provide a highly reliable abnormality detection method for a torque control system.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration of a controller in the control device for the electric vehicle of FIG.

FIG. 3 is a diagram showing details of the operation of the controller of FIG.

FIG. 4 is a diagram showing details of a traveling abnormality detection circuit in FIG.

5 is a diagram showing a truth table of the logic circuit shown in FIG. 4;

FIG. 6 is a diagram showing a truth table of a modified example of a logic circuit.

[Explanation of symbols]

1 ... Battery, 2 ... Main contactor, 3 ... Inverter,
4 ... Electric motor, 5 ... Controller, 6 ... Encoder, 7 ...
Current detector, 51 ... Waveform shaping circuit, 52 ... Phase sequence detection circuit, 53 ... Inverter drive circuit, 54 ... Running abnormality detection circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeyuki Yoshihara 2477 Kashima Yatsu, Takaba, Katsuta-shi, Ibaraki Prefecture 3 Hitachi Automotive Engineering Co., Ltd. (72) Hiroyuki Yamada, Katsuta-shi, Ibaraki Prefecture Kajima 2477 Yatsu 3 Hitachi Automotive Engineering Co., Ltd.

Claims (7)

[Claims] 1. An inverter for converting a DC power source of a battery into an AC power source of variable voltage and variable frequency, a three-phase AC motor for driving a vehicle, a current sensor for detecting a current of the three-phase AC motor, and an accelerator opening. Torque command computing means for determining a torque command of the three-phase AC motor according to the degree, and a three-phase AC current command for controlling the current of the three-phase AC motor based on the torque command and the output of the current sensor. A control device for an electric vehicle having a three-phase AC current command generating means for generating a signal, and a signal generating means for generating a signal for controlling the inverter based on the three-phase AC current command and a current flowing through the three-phase AC motor. In the above, based on the output of the phase sequence detection circuit for detecting the phase rotation of the three-phase AC current, the operation command means and the output of the shift switch for controlling the three-phase AC motor phase rotation, An abnormality detection device for an electric vehicle, comprising an abnormality detection means for detecting an abnormality of the control device. 2. The phase sequence detection circuit determines whether or not each phase u, v, w in the three-phase alternating current detected by the current sensor appears in a regular sequence, and the sequence of each phase is determined. The fault detection device for an electric vehicle according to claim 1, further comprising an abnormality detection unit that determines an abnormality when the order is not normal. 3. The electric vehicle according to claim 1, wherein the phase sequence detection circuit determines whether the voltage of each phase of the three-phase AC motor appears in a normal order. Failure detection device. 4. The electric vehicle according to claim 1, wherein the phase sequence detection circuit determines whether the voltage of each power switching element of the inverter appears in a normal order or not. Failure detection device. 5. The fault detection device for an electric vehicle according to claim 1, wherein the abnormality detection means includes a timer that outputs an abnormality signal after the abnormal state continues for a predetermined time or longer. 6. An inverter for converting 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, and the three-phase AC motor and a drive shaft of the vehicle in forward and reverse directions. FR command means for controlling the connecting portion to be connected,
A current sensor and a speed sensor for detecting a current and a rotation speed of the three-phase AC motor, a torque command calculation means for determining a torque command of the three-phase AC motor according to an accelerator opening, the torque command and the current sensor. Three-phase AC current command generating means for generating a three-phase AC current command for controlling the phase current flowing in the winding of the three-phase AC motor, based on the output of the three-phase AC current command and the three-phase AC In a control device for an electric vehicle having signal generating means for generating a signal to be applied to the gate of the inverter based on a phase current flowing in a winding of an electric motor, each phase u in the three-phase alternating current detected by the current sensor , V, w determine whether or not they appear in a regular order, and an abnormality detecting unit that determines that the phases are abnormal when the order of the phases is not in a regular order. The abnormality determination time, electric vehicle protection device is characterized in that a abnormal stop means for stopping the driving of the three-phase AC motor. 7. The electric vehicle protection device according to claim 6, wherein the abnormality detecting means includes a timer, and determines an abnormality when the abnormal state of the sequence of each phase continues for a predetermined time or longer.