JPH06249037A - Method and device for detecting abnormality of brushless motor, and electronic throttle system - Google Patents

Abstract

PURPOSE:To rapidly detect abnormalities of a brushless motor by using the signal of a magnetic pole sensor. CONSTITUTION:In an electronic throttle sensor which incorporates a magnetic pole position sensor 59 and is provided with a brushless motor 5B to control the opening of a throttle valve 2 of an internal combustion engine and an electromagnetic clutch 10 to connect/disconnect an output shaft of the brushless motor 5B to/from a rotary shaft of the throttle valve 2, the order of the detected magnetic pole position signal of the magnetic pole position sensor 59 which is changed according to the rotation of the brushless motor 5B with the normal order, and the electromagnetic clutch 10 is immediately disconnected when the comparative results are not agreed with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor abnormality detecting method and apparatus, and more particularly to an abnormality detecting method and apparatus suitable when the brushless motor is used as an actuator for controlling a throttle opening of an internal combustion engine. .

[0002]

2. Description of the Related Art As a conventional technique for detecting an abnormal condition when a brushless motor is stuck, there is, for example, the one disclosed in Japanese Patent Laid-Open No. 1-315641. In this conventional technique, U detected by the magnetic pole sensor of the brushless motor is used.
The values of the 3-bit signals corresponding to the phase, the V phase, and the W phase are monitored, and when all the 3-bit signals have the same value, it is determined that there is an abnormality.

[0003]

The above-mentioned prior art is 3b.
Since it detected that the it signals were all the same,
There is a problem that it takes time to detect an abnormality. For example, when this conventional technique is applied to a brushless motor used in an electronic throttle system that controls a throttle valve opening of an internal combustion engine of an automobile, when an abnormality occurs in the brushless motor during high-speed traveling, all 3 bit signals are the same. Since the abnormality is judged after the value becomes a value, the countermeasure against this is a problem after that.

Motors using permanent magnets are usually subjected to low temperature demagnetization. Therefore, a motor used in an automobile exposed to a cold environment has a problem that the motor characteristics are deteriorated when an excessive current is supplied at a low temperature. This phenomenon is an irreversible phenomenon, and once demagnetized, it cannot be restored.
Further, the motor arranged in the engine room may have an ambient temperature of 120 ° C. or higher, and if a current is applied to the motor in such a state as at room temperature, the motor will be burned. .

The electromagnetic clutch mounted on the electronic throttle is provided to disconnect the brushless motor and the throttle valve when an abnormality occurs in the brushless motor. However, if an abnormality occurs in the electromagnetic clutch, this is a problem. However, there is a problem in that maintenance is troublesome.

A first object of the present invention is to provide a brushless motor abnormality detecting method and apparatus and an electronic throttle system capable of immediately detecting an abnormality of the brushless motor.

A second object of the present invention is to provide an electronic throttle system which prevents deterioration of motor characteristics of a brushless motor.

A third object of the present invention is to provide an electronic throttle system which can easily detect an abnormality in the electromagnetic clutch.

[0009]

A first object of the present invention is to provide a brushless motor which incorporates a magnetic pole position sensor and controls the opening of a throttle valve of an internal combustion engine, an output shaft of the brushless motor and a rotary shaft of the throttle valve. In an electronic throttle system including an electromagnetic clutch for connecting / disconnecting the magnetic pole position sensor and the electromagnetic clutch, the order of the detected magnetic pole position signals of the magnetic pole position sensor that changes with the rotation of the brushless motor is compared with the normal order, and the comparison result is This is achieved by disengaging the electromagnetic clutch when not done.

The second object is to detect the temperature of the brushless motor or to estimate the temperature of the brushless motor from the engine cooling water temperature in an electronic throttle system using a brushless motor as an actuator for controlling the throttle opening of an internal combustion engine. However, when the motor temperature is lower than the predetermined low temperature and is higher than the predetermined high temperature, it is achieved by reducing the motor current.

A third object is to connect / disconnect a brushless motor which has a magnetic pole position sensor and controls the opening of a throttle valve of an internal combustion engine, and an output shaft of the brushless motor and a rotary shaft of the throttle valve. In an electronic throttle system including an electromagnetic clutch, the number of output pulses from the magnetic pole position sensor generated in response to a throttle valve opening command is counted, and the number of pulses counted within a predetermined time is out of a predetermined range. In this case, it is achieved by determining that an abnormality has occurred in the electromagnetic clutch.

[0012]

In the invention which achieves the first object, it is judged to be abnormal when even one of the signals output from the magnetic pole position sensor is out of order, so that the judgment is quick and the control response to it is high. improves.

In the invention for achieving the second object, the motor current is lowered when the motor temperature is high, so that the motor current is prevented from being overheated and burned out due to overheating. Further, since the motor current is reduced even when the temperature of the motor is low, the low temperature demagnetization of the permanent magnet built in the motor can be prevented.

In the invention which achieves the third object, the abnormality of the electromagnetic clutch can be determined only by counting the number of pulses and comparing this with a normal value.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram of an electronic throttle system according to an embodiment of the present invention. Throttle body 1
The throttle valve 2 is attached to the shaft valve of the throttle valve 2.
The accelerator drum 102 and the differential spring 4 are arranged. Further, the return spring 6 and the accelerator sensor 104 are arranged so as to move in conjunction with the accelerator drum 102.
The shaft end of the throttle valve 2 is connected to a gear 3 arranged in multiple stages, and the gear 3 is connected to an output shaft of a brushless motor 5B via an electromagnetic clutch 10. A magnetic pole sensor 59 is built in the brushless motor 5B. The control circuit includes an arithmetic circuit 122, a motor controller 50, and a display device 121.

Next, the overall operation will be described. First, the normal operation will be described. When the driver steps on the accelerator pedal, the accelerator drum 102 rotates in conjunction with the accelerator pedal. The rotation angle of this accelerator drum increases as the accelerator pedal is depressed,
The throttle valve 2 is opened to that extent, so that a large amount of air is sucked into the engine cylinder. A force is applied to the return spring 6 in a direction to close the throttle valve 2, and the return spring 6 is connected to the accelerator drum 102 and is in a position that balances the depression force of the accelerator pedal.
Is supposed to stop. The throttle valve 2 is opened and closed by the driver operating the accelerator pedal. The opening degree of the accelerator drum 102 at this time is determined by the accelerator sensor 10
4 is detected.

The electronic throttle system operates the throttle valve 2 in the opening / closing direction regardless of the opening degree of the throttle valve 2 regardless of how large the driver depresses the accelerator pedal. That is, the driver's intention is known from the amount of depression of the accelerator pedal, the driver's intention is realized, and the actual opening of the throttle valve 2 is determined based on a command from the control circuit so that the fuel consumption and torque are optimized. To control.

The torque of the brushless motor 5B is transmitted to the gear 3 via the electromagnetic clutch 10 and finally to the final stage gear provided on the shaft of the throttle valve 2 to rotate the throttle valve 2 in the opening / closing direction. Can be made. At that time, do not transmit the opening / closing operation of the throttle valve by the motor to the accelerator drum and accelerator pedal,
The differential spring 4 is arranged so as to absorb the rotational displacement.

For this reason, if an abnormality occurs in the brushless motor and the throttle valve 2 opens in the opening side direction, the vehicle will run out of control. For this reason, the electromagnetic clutch 10 is provided between the brushless motor 5B and the throttle valve 2, and when the brushless motor is abnormal, the electromagnetic clutch 10 is disengaged so that the driver can directly operate the throttle valve 2.

When an abnormality such as sticking occurs between the bearing of the brushless motor or between the rotor and the stator, the output of the motor can be cut off by disconnecting the electromagnetic clutch 10 provided between the throttle valve 2 and the brushless motor 5B. I have to. The opening of the throttle valve 2 is measured by the opening sensor 10
3 is detected. The magnetic pole signal 59S, which is the output signal of the magnetic pole sensor 59 incorporated in the brushless motor 5B, is
It is taken into the motor controller 50 and the arithmetic circuit 122.

The motor controller 50 uses the magnetic pole signal 59.
Based on S, a drive signal 50D for driving the brushless motor 5B is generated and output to the brushless motor 5B. The arithmetic circuit 122 extracts the angle information of the magnetic pole signal 59S and generates the clutch opening / closing signal 10S. Also,
The arithmetic circuit 122 uses the information such as the accelerator opening signal 104S from the accelerator sensor 104 and the opening signal 103S from the opening sensor 103 for detecting the throttle valve opening,
The motor start signal SS, a duty signal corresponding to the voltage applied to the motor, and a forward / reverse rotation signal that determines the rotation direction of the motor are generated and output to the motor controller 50. The states of the motor and the controller are displayed on the display device 121.

FIG. 2 is a circuit diagram of a detection circuit for detecting an abnormal magnetic pole position signal of the motor. The output signals of the magnetic pole sensor 59 are three-phase signals of U, V and W phases. The three signal lines are connected to the EOR circuits EOR1 to EOR3, respectively. These output signals are connected to the inputs of the inverter circuits INV2 to INV4, respectively, and are also connected to the input terminals of the host system 114 including a microcomputer or the like and the input terminals of the EOR circuits EOR4 and EOR5. And EO
The output signals of the R circuits EOR4 and EOR5 are input to the host system 114.

An accelerator opening signal 104S and a throttle valve opening signal 103S are input to the host system 114. The host system 114 outputs a start signal SS which is a start / stop signal for the motor, a duty signal DS for controlling the voltage applied to the motor, and a clutch opening / closing signal 10S for controlling the electromagnetic clutch when the magnetic pole signal is abnormal. The output signals of the inverter circuits INV2 to INV4 are
It is input to the AND circuits AND1 to AND3 and the NAND circuits NAND1 to NAND3.

The motor control circuit 50 shown in FIG.
Is a circuit that is often used, so its detailed description is omitted. The output signals of the AND circuit and the NAND circuit are input to the power circuit 200 that drives the motor. The power circuit 200 is usually composed of a three-phase inverter circuit,
The output signal is the drive signal 5 connected to the input of the motor.
It is 0D.

In this embodiment, the arithmetic circuit 122 is used to detect an abnormality in the magnetic pole signal. This will be described with reference to FIGS. Hall elements, Hall ICs, encoders, etc. are often used as the magnetic pole sensor. As shown in FIG. 3, the magnetic pole sensor has a phase difference of U phase, V phase, and W phase of 12
It outputs a three-phase signal with 0 degrees. It is well known that the three-phase signal and the induced voltage of the motor have a positional relationship as shown in the figure. If the output signal of the EOR circuit EOR4 shown in FIG. 2 is E1 and the output signal of the EOR circuit EOR5 is E2,
The magnetic pole signal 59S and the signals E1 and E2 have waveforms as shown in FIG. However, the forward / reverse rotation signal WC is assumed to be "L". Therefore, the magnetic pole signal 59S of the motor is always 120
When there is a phase difference of 1 degree, the signal E1 as shown in FIG. 3 and the signal E2 at the normal time are obtained.

Further, as shown in FIG. 3, if the three-phase magnetic pole signals are handled in binary numbers (U-phase is upper, W-phase is lower), the value of 3 bits data is the address data (FIG. 3). H'05 → H'04 → H'0
Only 6 types of values in the order of 6->H'02->H'03->H'01->H'05 are taken.

However, if the signal is fixed at "H" in the middle of the W phase due to a failure of the magnetic pole sensor, a wire breakage, etc., the signal E2 is originally H'05 unlike the normal state. → H'04 → H'06 should be changed to H'05 → H'04 → H'05, but the order of address data is returned in a wrong order even though the rotation direction is not changed. Also, so far H'01 ~
Although only the values up to H'06 are taken, the value H'07 is given. Therefore, if the 3-bit signal is detected at each edge of the signal E2, it can be determined whether the value is correct.

When an abnormality occurs in the detected signal, the arithmetic circuit 122 outputs a clutch opening / closing signal 10S for instructing the electromagnetic clutch to open / close, and disconnects the electromagnetic clutch. As described above, by disconnecting the electromagnetic clutch when the abnormality of the motor is detected, it is possible to switch to the normal throttle valve control (direct throttle valve control according to the depression amount of the driver).

FIG. 4 is a block diagram showing another embodiment of the motor control circuit. Regarding the circuit configuration, the same components as those shown in FIG. 2 are denoted by the same reference numerals in FIG. 4 as in FIG. In the embodiment of FIG. 2, the magnetic pole signal 59S output from the magnetic pole sensor 59 is directly input to the motor controller 50 so that a logic circuit generates a three-phase gate signal. In the example,
Once the data is taken into the host system 114 composed of a microcomputer or the like and the taken data is normal, the motor controller 50 is fed from the ports P10 to P12.
I am trying to output to. At this time, as described above, when an abnormality occurs in the magnetic pole signal, the clutch opening / closing signal 10S for disconnecting the electromagnetic clutch is output, and then the motor start signal SS is controlled to be turned off.

Motors using permanent magnets are usually subjected to low temperature demagnetization. Therefore, a motor used in an automobile exposed to a cold environment has a problem that the motor characteristics are deteriorated when an excessive current is supplied at a low temperature. This phenomenon is an irreversible phenomenon, and once demagnetized, it cannot be restored.
Further, the motor arranged in the engine room may have an ambient temperature of 120 ° C. or higher, and if a current is applied to the motor in such a state as at room temperature, the motor will be burned. .

FIG. 5 is a block diagram of a control circuit for solving the above-mentioned problem. In this embodiment, the temperature of the motor is detected and the current flowing through the motor is controlled. The shaft of the throttle valve 2 is connected to the output shaft of the brushless motor 5B via the electromagnetic clutch 10. An opening sensor 103 and an accelerator sensor 104 are attached to the throttle valve 2. The output signals of these two sensors are input to the arithmetic circuit 122 as an opening signal 103S and an accelerator opening signal 104S. Further, the arithmetic circuit 122 is provided with an opening command 119 and a water temperature signal 1 from the water temperature gauge 125.
25S, the temperature signal 60S of the temperature sensor 60 attached to the motor, and the magnetic pole signal 59S are input. Since the brushless motor 5B is directly attached to the engine, the temperature of the motor can be estimated from the cooling water temperature of the engine.

From the arithmetic circuit 122, a display signal 121S for displaying the state of the motor, a state of water temperature, etc., a forward / reverse signal WC for instructing forward / reverse rotation of the motor, and a voltage applied to the motor are controlled. Duty signal DS for controlling and clutch opening / closing signal 1 for controlling ON / OFF of the electromagnetic clutch
0S and a start signal SS for instructing start / stop of the motor are output. Further, the motor controller 50 and the brushless motor 5B are connected by a drive signal 50D.

FIG. 6 is a graph for explaining the control of the current passed through the motor. The horizontal axis is the motor temperature, and the vertical axis is
It has a temperature constant that corresponds to the magnitude of the current passed through the motor. As shown in this graph, the motor current is suppressed when the temperature of the motor is low and when the temperature is high near engine overheating. As a result, the opening and closing speed of the throttle valve is slightly slowed, but demagnetization and burnout of the motor can be prevented. Further, as a control method, there are control patterns shown by the solid line and the dotted line in the graph.

FIG. 7 is a diagram for explaining a method of detecting an abnormality of the electromagnetic clutch 10 used for transmitting the torque of the motor to the throttle valve. The horizontal axis is time. Abnormalities of the electromagnetic clutch 10 may include clutch slippage and sticking. Here, a method of detecting slippage of the clutch will be described.

With the circuit configuration shown in FIG. 5, the opening command 119
However, it is assumed that it changes from a to b as shown in FIG. At that time, since the opening of the throttle valve and the rotation angle of the motor are determined by the gear ratio, if the opening of the throttle valve is constant, the number of pulses output from the magnetic pole sensor is always constant. However, the number of pulses of the magnetic pole signal 59S increases when oil or foreign matter is mixed in the clutch plate or when slippage occurs due to wear of the disk surface. Also, the slip of the clutch plate extends the response time of the throttle valve. This is shown as a signal from the magnetic pole sensor in FIG.

Therefore, if the pulse number of the magnetic pole sensor 59 for the opening command 119 is detected by a counter or the like, it is possible to detect whether the clutch is normal or abnormal. When this slippage is detected, the display device 121 shown in FIG.
The state of the clutch is displayed on and control is performed to disengage the clutch. Therefore, it is possible to detect the occurrence of an abnormality in the clutch without regularly inspecting the wear of the clutch.

In this embodiment, the system using the brushless motor and the magnetic pole sensor has been described, but the same effect can be obtained by using a sensor capable of detecting the rotation angle of a motor other than the brushless motor such as another DC motor or a step motor. it can.

[0038]

According to the present invention, a failure of the magnetic pole sensor can be promptly inspected by detecting the signal of the magnetic pole detector every 60 degrees in electrical angle and making an abnormality judgment. The clutch can be disengaged quickly, so that the vehicle can be driven safely.

Further, by measuring or estimating the temperature of the motor,
Since the current supplied to the motor is controlled, demagnetization and burnout of the motor can be prevented, and safety is improved.

By detecting the slip of the electromagnetic clutch based on the magnetic pole signal of the brushless motor, the slip can be detected without using a special sensor.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an electronic throttle system according to an embodiment of the present invention.

FIG. 2 is a control circuit diagram of a motor.

FIG. 3 is a timing chart of the circuit diagram shown in FIG.

FIG. 4 is a circuit diagram showing another embodiment of the control circuit of the motor shown in FIG.

FIG. 5 is a circuit configuration diagram for detecting a motor temperature.

FIG. 6 is a graph showing temperature constants with respect to motor temperature.

FIG. 7 is a timing chart showing a method for detecting slippage of a clutch.

[Explanation of symbols]

1 ... Throttle body, 2 ... Throttle valve, 21 ... Throttle valve (valve) shaft, 3 ... Gear, 4 ... Differential spring, 5B ... Brushless motor, 50 ... Motor controller, 50D ... Drive signal, 59 ... Magnetic pole sensor, 59S
... Magnetic pole signal, 6 ... Return spring, 60 ... Temperature sensor, 60S
... temperature signal, 10 ... electromagnetic clutch, 10S ... clutch opening / closing signal, 102 ... accelerator drum, 103 ... opening sensor, 103S ... opening signal, 104 ... accelerator sensor, 1
04S ... accelerator opening signal, 114 ... host system, 1
19 ... Opening degree instruction, 121 ... Display device, 122 ... Arithmetic circuit, 125 ... Water thermometer, SS ... Activation signal, 200 ... Power circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuya Yoshida 2520 Takaba, Katsuta City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division

Claims (11)

[Claims] 1. A method for detecting an abnormality in a brushless motor, wherein when the order of the magnetic pole position signals that change due to the rotation of the brushless motor is different from the order stored in advance, it is determined that the brushless motor is abnormal. 2. An abnormality detection of the brushless motor, characterized in that when the order of the magnetic pole position signals that change according to the rotation of the brushless motor is different from the order when the brushless motor is normal, it is determined that the brushless motor is abnormal. Method. 3. The method for protecting a brushless motor according to claim 1 or 2, wherein the brushless motor is stopped when it is determined to be abnormal. 4. A means for monitoring the order of the magnetic pole position signals that change according to the rotation of the brushless motor, a memory storing the order of the magnetic pole position signals when the brushless motor is normal, and the order and memory for monitoring. An abnormality detecting device for a brushless motor, comprising: a means for comparing the above-mentioned order and a means for immediately determining an abnormality when the comparison results do not match. 5. A brushless motor protection device, comprising: the brushless motor abnormality detection device according to claim 4; and means for stopping the brushless motor when the determination means determines an abnormality of the brushless motor. apparatus. 6. A brushless motor for controlling the opening of a throttle valve of an internal combustion engine, comprising a magnetic pole position sensor, and an electromagnetic clutch for connecting / disconnecting an output shaft of the brushless motor and a rotary shaft of the throttle valve. In an electronic throttle system provided, comparing the order of the detected magnetic pole position signal of the magnetic pole position sensor that changes with the rotation of the brushless motor and the normal order, and disengaging the electromagnetic clutch when the comparison result does not match. A method for controlling an electronic throttle system, characterized by: 7. A brushless motor for controlling the opening of a throttle valve of an internal combustion engine, which incorporates a magnetic pole position sensor, and an electromagnetic clutch for connecting / disconnecting an output shaft of the brushless motor and a rotary shaft of the throttle valve. In an electronic throttle system provided, means for comparing the order of the detected magnetic pole position signals of the magnetic pole position sensor, which changes with the rotation of the brushless motor, and the normal order, and the electromagnetic clutch is disengaged when the comparison result does not match. An electronic throttle system comprising: a releasing means. 8. An electronic throttle system using a brushless motor as an actuator for controlling the throttle opening of an internal combustion engine, a means for detecting the temperature of the brushless motor or estimating the temperature of the brushless motor from the engine cooling water temperature, and a motor. An electronic throttle system comprising: means for reducing a motor current when the temperature is lower than a predetermined low temperature and when the temperature is higher than a predetermined high temperature. 9. A brushless motor which incorporates a magnetic pole position sensor to control the opening of a throttle valve of an internal combustion engine, and an electromagnetic clutch which connects / disconnects an output shaft of the brushless motor and a rotary shaft of the throttle valve. In an electronic throttle system provided, means for counting the number of output pulses from the magnetic pole position sensor generated in response to the throttle valve opening command, and when the number of pulses counted within a predetermined time is outside a predetermined range Is a means for judging that an abnormality has occurred in the electromagnetic clutch. 10. The electronic throttle system according to claim 9, further comprising means for disengaging the electromagnetic clutch and displaying a message to that effect when it is determined that an abnormality has occurred in the electromagnetic clutch. 11. The electronic device according to claim 7, wherein a motor other than the brushless motor is used instead of the brushless motor, and a rotation angle sensor is used instead of the magnetic pole position sensor. Throttle system.