JP2005253156A - Fault detector in motor controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable fault detector in a motor controller for a vehicle which detects the fault of a relay exactly and reduces the fault. <P>SOLUTION: The problem is solved by being equipped with a motor operation stopping means which stops a motor before the motor controller for a vehicle starts the control of the motor, and a relay switching control means which switches on or switches off the relay for power source two or more times and cleans the pollution adhering to the contact of the relay for power source. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to failure detection for a power supply relay of a motor control device mounted on a vehicle.

In order to meet social needs such as improving safety and operability for automobiles, there is a motor control device that uses a microcomputer to control motors to support and facilitate driving, driving, and operation of cars. Many have come to be installed in vehicles. These motor control devices use many relays such as power supply relays and motor relays in order to improve safety and reliability by fail-safe and self-diagnosis. The relay may be affected by dust generated in the traveling environment of the vehicle, and the contact of the relay may cause an abnormality in the dirt operation. If these relays fail, the above-mentioned fail-safe cannot be achieved. Therefore, it is necessary to take safety measures such as detecting the failure and stopping the motor control, and Patent Document 1 introduces the method.
JP 2000-72020 A

  However, in such a method, when an abnormality occurs in the contact of the relay and a failure occurs intermittently, there is a possibility that the failure cannot be detected accurately due to the timing of detecting the relay failure. In addition, since the failure of the relay is not cured, it is necessary to remove the motor control device including the relay from the vehicle and replace it with a normal motor control device.

  An object of the present invention is to provide a highly reliable vehicle motor control device failure detection device that accurately detects a failure of a relay and reduces the failure.

Means for Solving the Problems and Effects of the Invention

A failure detection device for a vehicle motor control device according to the present invention includes a power relay connected to a power line of a battery, a motor relay that controls energization of the motor, and a motor that receives power supply via the power relay. A vehicle motor control device comprising a control unit for controlling a relay for the vehicle,
Before the vehicle motor control device starts controlling the motor,
The control unit includes motor operation stopping means for stopping the motor,
And a relay open / close control means for performing on / off control of the power supply relay a plurality of times and removing dirt adhering to the contact of the power supply relay.

  If it does in this way, before a motor control apparatus starts control of a motor, the control part will perform ON / OFF operation | movement several times in order to detect the failure of a power supply relay. As a result, every time the vehicle travels, dirt adhering to the contact of the power supply relay of the motor control device is scattered to restore the contact, thereby reducing the failure of the relay.

  In the vehicle motor control device failure detection device according to the present invention, the relay opening / closing control means charges the capacitor of the control unit when supply current is supplied from the power supply line to the control unit via the power supply relay. The power relay can be controlled to be turned on and off at intervals larger than the time constant of the charging current.

  In this case, since the failure detection device firmly controls the opening and closing of the contact of the power relay, it is possible to reliably remove the dirt adhering to the contact. If the ON / OFF interval is too short, the contacts cannot be opened and closed properly, and if the ON / OFF interval is too long, the time spent for detecting the failure of the power relay becomes too long, and the motor control of the motor control device starts. That is, the start of the system is delayed.

  Further, the failure detection device for a vehicle motor control device according to the present invention is such that the contact of the relay opening / closing means is caused by a breaking arc discharge generated when the supply current flowing through the power supply relay opens the contact of the energized power supply relay. The power relay can be configured to be turned off when the critical current to be welded falls below.

  In this way, even when the peak current of the supply current flowing through the power supply relay is very large, such as several tens of amperes, when the power supply relay is turned on / off for fault detection, the relay contact is disconnected. It is not welded or worn out by arc discharge.

Moreover, in the failure detection device for a vehicle motor control device of the present invention, the control unit includes:
Relay on / off control means for turning on the power relay again after the power relay is turned on / off multiple times;
An open-circuit failure detection means for generating a power relay failure signal indicating a failure of the power supply relay when the output voltage of the power supply relay falls below a threshold value of the logic circuit at the time of turning on again can be provided.

  In this way, the power relay is forcibly turned ON / OFF several times, the dirt adhering to the contact of the power relay of the motor control device is scattered to recover the contact, and then the failure of the relay is checked. Since the inspection is performed, it is possible to accurately detect the failure of the power relay.

  Further, the failure detection device for a vehicle motor control device according to the present invention is such that when the relay opening / closing control means controls the power supply relay to be turned on / off a plurality of times to remove the dirt adhering to the contact of the power supply relay, The controller can be configured to stop the motor by turning off the motor relay.

  In this way, when the power supply relay is controlled to turn on / off for failure detection, the motor is in a stopped state, so that it is possible to reliably prevent the motor control device from malfunctioning due to this failure detection. Can do. As a result, the safety of the motor control device is improved in combination with the effect of the failure detection device.

  Further, the failure detection device for a vehicle motor control device according to the present invention is such that when the relay opening / closing control means controls the power supply relay to be turned on / off a plurality of times to remove the dirt adhering to the contact of the power supply relay, The motor can also be configured to stop by stopping the motor drive circuit that controls the current flowing through the motor.

  In this way, when the power supply relay is controlled to turn on / off for failure detection, the motor is in a stopped state, so that it is possible to reliably prevent the motor control device from malfunctioning due to this failure detection. Can do. As a result, the safety of the motor control device is improved in combination with the effect of the failure detection device.

  Further, the failure detection device for a vehicle motor control device according to the present invention is such that when the ignition switch is in the start position and the engine is started, the relay opening / closing control means is used for the power supply to remove dirt attached to the contact of the power supply relay. The relay may be configured to be turned on / off a plurality of times.

  In this case, since the fine sound generated when the relay is turned on / off to detect a failure of the power relay is buried in the engine start sound, the quietness of the vehicle is not affected.

Further, in the vehicle motor control device failure detection device of the present invention, the open failure detection means,
A binary counter that counts the pulses of the power relay control signal that turns the power relay on and off;
A first AND circuit that takes the logical product of the output of the binary counter and the power relay control signal;
A second AND circuit that takes the logical product of an inverted power signal obtained by dividing the polarity of the power signal obtained by dividing the power voltage generated in the control unit by the supply current energized through the power relay and the output of the first AND circuit. Prepared,
When the output of the second AND circuit is at a high level, a failure in the open state of the power relay can be detected.

  In this way, immediately after the controller turns on / off the power relay several times and removes dirt on its contacts, the power relay is energized and whether the power supply voltage supplied to the controller exceeds a predetermined value. Whether it can be examined using logical operations. As a result, the failure detection apparatus can accurately determine whether or not the power supply relay is in an open state.

The best mode of a failure detection apparatus for a vehicle motor control apparatus according to the present invention will be described below with reference to the accompanying drawings. The configuration and function of the failure detection device of the vehicle motor control device will be described with reference to FIG. Power is supplied from the power supply line connected to the battery 10 to the control unit (hereinafter referred to as “ECU”, ECU: Electronic Control Unit) 100 via the power supply relay 20. At this time, the power supply line passes through the power supply relay. supply current I _s flows through the ECU 100. The ECU 100 is connected to a motor 40 that controls or assists vehicle travel, steering, braking, and the like, and a motor relay 30 that controls energization of the motor 40.

The ECU 100, which is a failure detection device, includes a stabilized power circuit 110 that inputs a supplied power and outputs a constant voltage power supply, and various control signals S that receive the constant voltage power and control a motor, a relay, and the like. ON / OFF of the microcomputer 120 (comprising CPU: Central Processing Unit or MPU: Micro Processing Unit etc.) that generates _PR , _SMR , _SMD, etc. Gate drive circuit 130 that generates a gate signal that controls OFF, semiconductor switch that is turned ON / OFF by the gate signal (uses P-channel MOS FET or N-channel MOS FET, MOS FET: Metal-Oxide-Semiconductor Field Effect Transistor) The motor drive circuit 140 that controls the rotation of the motor 40, the power supply relay open / close control / fault detection circuit 150 that controls the open / close of the power relay 20 and the motor relay 30, respectively, the motor relay control circuit Consisting of 160.

  FIG. 5 shows the connections of the motor 40, the motor drive circuit 140, the battery 10 (or the battery power line), and the motor relay 30 when a brushless motor is used as the motor 40. The three-phase currents flowing in the brushless motor 40 are U-phase, V-phase, and W-phase currents. The six semiconductor switches Q141, Q142, Q143, Q144, Q145 and Q146 (N ON / OFF control is performed by each gate signal (PWM1, PWM2, PWM3, PWM4, PWM5, PWM6, PWM: Pulse Width Modulation) applied to the gate of the channel MOS FET). The motor relay 30 is inserted between the battery 10 and the motor drive circuit 140 to control the operation stop / rotation operation of the motor 40.

The function of the failure detection device of the vehicle motor control device and the operation of each part will be described using the time chart of FIG. 2 and the flowchart of FIG. When the ignition switch is rotated to the start position and the engine is started, that is, before the vehicle motor control device is started (control of the motor 40 is started), a check before starting the system of the vehicle motor control device is performed in the control step P1. Begins with. At this time, a self-diagnosis of the ECU 100 is also performed. In the control step P2, the power relay 20 is turned ON / OFF three times at intervals of 100 ms (greater than the time constant of the charging current _ic flowing through the smoothing capacitor C _{s of the} ECU 100) three times. In FIG. 2, the control step P2 is three times of 1 ^st , 2 ^nd , and 3 ^{rd when} the control signal SPR is at the high level, that is, the power supply relay 20 is turned on. At this time, the power relay 20 can open and close the contact points at an optimum interval, so that dirt attached to the contact points can be removed appropriately.

When the power supply relay 20 is first turned ON, the supply current I _s flowing through the power supply relay 20 (I _s = I _c + i _c , where I _c is the consumption current of the ECU 100) is the internal resistance of the power supply line and the power supply relay 20 Since it is extremely small (less than 0.1Ω), the peak value of the charging current _ic flowing through the smoothing capacitor C _s reaches several tens of A (amperes), and the relay contact is turned on (OFF) around the peak value and fixed. There is a possibility that a breaking arc discharge occurs at the moment when the movable contact is separated from the contact, and the two contacts are welded (the current at which this welding occurs is called “critical current”). So open the contact OFF the power supply relay 20 when the supply current I _s becomes less than the number A through the power supply relay 20, preventing welding or wear of the contacts due to the blocking arcing.

  Next, in control steps P3 to P5, the power supply relay 20 is turned ON again to detect a failure in the open state of the power supply relay 20 (also referred to as “open mode”). In FIG. 2, open mode failure detection is performed to check whether the contact in the closed state is abnormal (non-conduction or large resistance between the contacts) at the fourth ON time of the power relay 20 (details will be described later) To do. When a failure in the open mode is not detected, that is, when the power supply relay 20 is normal, the process proceeds to control step P7, the system of the vehicle motor control device is started, and the ECU 100 starts to control the motor 40. If a failure in the open mode is detected, the process proceeds to control step P6, the system is stopped, and the driver is notified by a lamp or the like that an abnormality has occurred in the vehicle motor control device.

Time T including three consecutive ON / OFF of power supply relay 20 for removing contamination of contacts in control step P2 and the fourth ON of power supply relay 20 for detecting faults in control steps P3 to P5 between _a of T _B, the control signal S _MR Do motor relay 30 becomes OFF is OFF (contacts open), or the control signal S _MD is turned OFF motor drive device 140 is turned OFF In any case, since energization to the motor 40 is stopped, the motor 40 is kept in a stopped state, and the possibility of malfunction of the motor 40 due to the ON operation of the power supply relay 20 can be reliably prevented.

Here, the above-described open mode failure detection will be described with reference to FIG. FIG. 3 shows a circuit configuration of the power supply relay switching control / fault detection circuit 150. The control signal _SPR output from the microcomputer 120 turns the semiconductor switch Q of the P-channel MOS FET on / off to control the contact of the power supply relay 20. Control signal parallel binary count output and a control signal of the low-order 2 bits of the code of the S _PR pulse binary counter operating in negative edge of 151 is being input logical product of three inputs is taken to the 1AND circuit control signal S 4 th pulse _PR generates a time selection signal S _T to be simultaneously high level of the high-level time. When time selection signal S _T is at a high level, the output voltage V _s is generated at the output of the power supply relay 20 is turned ON to the power supply line of the power supply voltage V _B power supply relay 20, the resistor R and the constant voltage diode ANDs of both type inverted power signal obtained by inverting the polarity of the voltage divider and constant-pressurization and power signal S _v and the time selection signal S _T to the second 2AND circuit D, and the fault detection signal S _F Occur.

When time selection signal S _T is at a high level, there is an abnormality in the power supply relay 20 (contact is opened or faulty electrical continuity, etc.) when the power signal S _v is below the threshold value V _th of the logic circuit, inversion which inverts the polarity The power supply signal goes high. At this time, the output of the fault detection signal S _F is the high level of the 2AND circuit, i.e. "1", the open mode failure of the power supply relay 20 is detected. Incidentally, looking at the time relationships of various parts of the power supply relay off control and fault detection circuit 150 in detail, the timing of the selection signal S _T and the power signal S _v there is a response delay of the power supply relay 20 [within 10 ms] Adjustment It is necessary to do, but it is omitted because it is detailed. Since the failure detection signal S _F is monitored is inputted to the microcomputer 120, ECU 100 can detect the accurately a failure of the power supply relay 20.

The circuit block diagram which shows the whole structure of the failure detection apparatus of the electronic controller for vehicles of this invention. The timing chart explaining the function of the failure detection apparatus of the electronic controller for vehicles of the present invention. FIG. 3 is a circuit diagram showing a circuit configuration of a power supply relay open / close control / fault detection circuit 150; The flowchart explaining the function of the failure detection apparatus of the electronic control apparatus for vehicles of this invention. The circuit diagram explaining the connection state of the motor drive circuit of the failure detection apparatus of the electronic control apparatus for vehicles of this invention, the relay for motors, a battery, and a motor.

Explanation of symbols

10 battery
20 Relay for power supply
30 Motor relay
100 ECU (control unit, failure detection device)
110 Stabilized power circuit
120 microcomputer (CPU / MPU)
130 Gate drive circuit (motor operation stop means)
140 Motor drive circuit
150 Relay open / close control and failure detection circuit for power supply (relay open / close control means / open failure detection means)
160 Relay control circuit for motor (Motor operation stop means)
151 binary counter
152 1st AND circuit
153 Second AND circuit
Q, Q141, Q142, Q143, Q144, Q145, Q146 Semiconductor switch (MOS FET)
Cs smoothing capacitor
S _PR , S _MR , S _MD control signal
S _T Time selection signal
S _v power signal
S _F Fault detection signal
V _B battery power line
Output voltage of V _s power supply relay

Claims (7)

A vehicle including a power relay connected to a power line of a battery, a motor relay that controls energization to a motor, and a control unit that receives power supply via the power relay and controls the motor relay Motor control device for
Before the vehicle motor control device starts controlling the motor,
The control unit is a motor operation stopping means for stopping the motor,
Relay on / off control for the power relay a plurality of times, and relay open / close control means for removing dirt adhering to the contact of the power relay;
A failure detection device for a vehicle motor control device. When the supply current is supplied from the power line to the control unit via the power relay, the relay opening / closing control means
2. The failure detection device for a vehicle motor control device according to claim 1, wherein the power supply relay is on / off controlled at intervals larger than a time constant of a charging current charged in the capacitor of the control unit. The relay opening / closing means includes
The power supply relay is turned off when the supply current flowing through the power supply relay falls below a critical current at which the contact is welded due to a break arc discharge generated when the power supply relay contact is opened. The failure detection device for a vehicle motor control device according to claim 1 or 2. The controller is
The relay opening / closing control means for turning on the power relay again after the power relay is turned on / off multiple times;
An open failure detecting means for generating a power relay failure signal indicating a failure of the power relay when the output voltage of the power relay falls below a threshold value of the logic circuit during the ON time;
The failure detection device for a vehicle motor control device according to any one of claims 1 to 3, further comprising: When the relay opening / closing control means removes dirt adhering to the contact of the power relay by performing on / off control of the power relay a plurality of times,
The failure detection device for a vehicle motor control device according to any one of claims 1 to 4, wherein the motor operation stopping means causes the motor to stop when the control unit turns off the motor relay. . When the relay opening / closing control means removes dirt adhering to the contact of the power relay by performing on / off control of the power relay a plurality of times,
The vehicle operation device according to any one of claims 1 to 5, wherein the motor operation stopping unit stops the motor by stopping a motor drive circuit that controls a current flowing through the motor by the control unit. Failure detection device for motor control device. 7. When the ignition switch is in a start position and the engine is started, the relay opening / closing control means controls the power relay on and off a plurality of times in order to remove dirt adhered to the contact of the power relay. The failure detection device for a vehicle motor control device according to any one of the above.

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