JP2012182929A - Abnormality detection device and motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect abnormality in a sensor for measuring an electrical angle of a rotor for a synchronous motor while the synchronous motor is in a resting state.SOLUTION: An abnormality detection device includes: a first measurement section 70 for measuring an electrical angle of a rotor for a synchronous motor 31 from output states of a plurality of Hall sensors; second measurement sections (72, 46, 48) that measure an electrical angle in a different way from the Hall sensors; and an abnormality detection section 48 that detects that the electrical angle output by the first measurement section 70 has an abnormality by estimating output states of the plurality of Hall sensors from the electrical angle measured by the second measurement sections (72, 46, 48) when the synchronous motor 31 is in a resting state and comparing the estimated result to the output states measured by the first measurement section 70.

Description

  The embodiments discussed herein relate to the detection of anomalies occurring in a sensor that detects the electrical angle of a synchronous motor rotor.

  A hall sensor using a hall element is known as a sensor for detecting the electrical angle of the rotor of the synchronous motor. The hall sensor generates an output signal corresponding to the electrical angle of the rotor magnet. For this reason, it is possible to detect abnormality of the Hall sensor depending on whether or not the change of the output signal of the Hall sensor according to the rotation of the motor follows a predetermined order.

  A hall sensor that outputs a position detection signal according to the rotational position of the rotor of the motor, an angle estimation unit that calculates an estimated motor angle of the motor based on the back electromotive voltage of the motor, and a position detection output from the hall sensor A detection unit that detects the rotation angle of the motor based on the combination of signals, a comparison calculation unit that compares the detected rotation angle and the estimated motor angle, and a failure that detects abnormality of the Hall sensor based on the comparison result of the comparison calculation unit There is known an electric power steering device including a safe calculation unit.

  There is also known an electrical angle detection device that obtains an electrical angle by using the difference in inductance between phases depending on the angle of the rotor when the motor rotates at a predetermined rotational speed or less.

JP 2005-335591 A Japanese Patent Laid-Open No. 7-177788

  Conventionally, an abnormality detection of a sensor used for detecting an electrical angle of a rotor of a synchronous motor has been performed while the synchronous motor is rotating. In this case, if the synchronous motor is stopped, the sensor abnormality cannot be detected until the rotation is restarted, so that the sensor abnormality detection is delayed.

  An apparatus and method according to an embodiment is directed to detecting an abnormality of a sensor that measures an electrical angle of a rotor of a synchronous motor while the synchronous motor is in a stationary state.

  An abnormality detection apparatus according to an embodiment includes a first measurement unit that measures an electrical angle of a rotor of a synchronous motor from output states of a plurality of Hall sensors, and a second measurement unit that measures an electrical angle by a method different from the Hall sensor. When the synchronous motor is in a stationary state, the output state of the plurality of Hall sensors is estimated from the electrical angle measured by the second measuring unit, and the estimated result is compared with the output state measured by the first measuring unit. And an abnormality detection unit that performs an abnormality detection process for detecting that there is an abnormality in the electrical angle output by the first measurement unit.

  According to the apparatus or method of the present disclosure, it is possible to detect an abnormality of a sensor that measures the electrical angle of the rotor of the synchronous motor while the synchronous motor is in a stationary state. For this reason, the detection delay of the abnormality of the sensor can be prevented.

It is a block diagram of an electrohydraulic power steering apparatus. It is a block diagram of the control system of an electrohydraulic power steering apparatus. (A)-(C) are explanatory drawings of motor control. It is a state transition diagram of motor control. It is explanatory drawing of the change of the rotational speed at the time of being controlled by the state transition of FIG. It is a state transition diagram of the 1st example of motor control. It is explanatory drawing of the change of the rotational speed at the time of being controlled by the state transition of FIG. It is explanatory drawing of a Hall sensor. It is a figure which shows an example of the relationship between a Hall sensor output and an electrical angle. It is explanatory drawing of the 1st example of a process of a failure detection method. It is explanatory drawing of the 2nd example of a process of a failure detection method. It is explanatory drawing of the electric current which flows into a stator coil. (A)-(F) is explanatory drawing of the direction of each coil electric current in each drive pattern, and the polarity of a U-phase magnetic pole, a V-phase magnetic pole, and a W-phase magnetic pole. (A)-(C) are the time charts of the drive signal of a U-phase low side element, a V phase low side element, and a W phase low side element, (D) is a time chart of the drive current of a motor. It is explanatory drawing of the determination method of the electrical angle of a rotor. It is explanatory drawing of the 3rd example of a process of a failure detection method. It is a state transition diagram of the 2nd example of motor control. (A)-(C) are explanatory drawings of the motor control by the state transition of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, a case where the abnormality detection device according to the embodiment is applied to an electrohydraulic power steering device will be described. However, the abnormality detection device according to the embodiment may be applied to, for example, an electric power steering device. The abnormality detection device according to the embodiment can be applied to various devices using a measurement sensor that measures the electrical angle of the rotor of the synchronous motor.

  FIG. 1 is a configuration diagram of an electrohydraulic power steering apparatus. Reference numeral 4 indicates a front wheel of the vehicle. Reference numerals 2, 3, 5 and 6 respectively indicate a steering wheel, a column shaft, a rack and a pinion of the steering mechanism of the front wheel 4. Reference numerals 23 to 25 and 30 denote a vehicle speed sensor, an engine control device (EFI-ECU), an alarm output unit, and a power source, respectively.

  The electrohydraulic power steering apparatus 1 includes a control unit 10, a torque sensor 21, a rudder angle sensor 22, a motor 31, a pump 32, a power cylinder 33, and a position sensor 70.

  The torque sensor 21 and the steering angle sensor 22 detect the steering force and the steering angle of the steering wheel 2, respectively. The vehicle speed sensor 23 detects the speed of the vehicle. The engine control device 24 is an electronic control device that controls an engine provided in the vehicle, and detects the engine speed when the engine is controlled.

  The control unit 10 drives the motor 31 according to the steering force, the steering angle, the vehicle speed, and the engine speed detected by the torque sensor 21, the steering angle sensor 22, the vehicle speed sensor 23, and the engine control device 24, respectively. Further, the state of the ignition switch is also sent from the engine control device 24 to the control unit 10.

  The motor 31 is a three-phase synchronous motor (DC brushless motor) that supplies power to the pump 32. The pump 32 supplies an oil pressure to the oil chamber of the power cylinder 33 to apply an auxiliary force that assists the steering force of the driver to the rack 5 of the steering mechanism of the front wheels 4.

  The control unit 10 includes a processing unit 40, a pre-driver 50, a power unit 60, an amplifier 71, and a relay 80. The processing unit 40 generates a control signal for the motor 31 according to the steering force, the steering angle, the vehicle speed, and the engine speed detected by the torque sensor 21, the steering angle sensor 22, the vehicle speed sensor 23, and the engine control device 24, respectively. .

  The position sensor 70 detects the electrical angle of the rotational position of the rotor of the motor 31. In this specification, the electrical angle at the rotational position of the rotor may be referred to as “the electrical angle of the rotor”. The position sensor 70 may include, for example, a hall sensor or a resolver that detects the electrical angle of the rotor of the synchronous motor.

  When generating the control signal for the motor 31, the processing unit 40 determines the phase coil to be energized according to the detection signal of the position sensor 70. The processing unit 40 outputs a phase current control signal for turning on and off a switching element that controls a phase current flowing to each phase coil of the motor 31.

  The pre-driver 50 amplifies the phase current control signal output from the processing unit 40 and supplies it to the power unit 60. The power unit 60 drives a switching element that controls the phase current flowing from the power supply 30 to each phase coil of the motor 31 in accordance with the amplified phase current control signal.

  The processing unit 40 detects the abnormality of the electrohydraulic power steering apparatus 1 according to the temperature signal detected by the power unit 60, each phase current of the motor 31, that is, the current detection signal indicating the detected value of the drive current, and the voltage of the power source 30. Is detected. The amplifier 71 amplifies the current detection signal and supplies it to the processing unit 40.

  In addition, the processing unit 40 specifies the electrical angle of the rotor of the motor 31 using the current detection signal, and detects an abnormality in the detection angle determined by the detection signal of the position sensor 70.

  The processing unit 40 generates a relay drive signal that drives the relay 80. When the processing unit 40 detects a predetermined abnormality, the processing unit 40 controls the relay 80 to stop the supply of current from the power supply 30 to the power unit 60.

  Further, the processing unit 40 outputs an alarm notifying the abnormality to the driver via the alarm output unit 25. The alarm output unit 25 may be a vehicle meter or a navigation device. For example, the processing unit 40 may output an alarm notifying the abnormality of the position sensor 70 via the alarm output unit 25.

  FIG. 2 is a configuration diagram of a control system of the electrohydraulic power steering apparatus 1. The processing unit 40 includes a flow rate command value calculation unit 41, a rotation speed command value calculation unit 42, a subtraction unit 43, a feedback (FB) control unit 44, a duty calculation unit 45, a drive element determination unit 46, a rotation A number calculation unit 47, a position sensor failure detection unit 48, and a determination unit 49 are provided.

  The power unit 60 includes switching elements Q1 to Q6, a current sensor 72, and a temperature sensor 73.

The flow rate command value calculation unit 41 determines the command value of the flow rate of the hydraulic oil discharged from the pump 32 according to the steering force, the steering angle, and the vehicle speed detected by the torque sensor 21, the steering angle sensor 22, and the vehicle speed sensor 23, respectively. calculate.
The flow rate command value calculation unit 41 calculates a basic amount of flow rate based on the steering state of the steering wheel 2 detected by the steering force and the steering angle, and based on the calculated flow rate, the flow rate increases as the vehicle speed increases. By correcting so as to be smaller, a command value for the flow rate of the hydraulic oil is calculated.
Further, the flow rate command value calculation unit 41 determines whether or not the steering assist control by driving the pump 32 can be performed based on the engine drive state determined from the engine speed sent from the engine control device 24. Specifically, when it is determined that the engine is not driven, the power supply 30 that supplies power for driving the pump 32 is charged, and an alternator (not shown) is not generating power. The steering assist control is not performed in order to prevent a decrease in the charging rate of the power source 30.
In addition, when generating the command value of the flow rate of the hydraulic oil, a configuration using only one of the torque sensor 21 and the steering angle sensor 22 may be used as a sensor for detecting the operation state of the steering wheel 2.
The rotation speed command value calculation unit 42 calculates a rotation speed command value that is a rotation speed command value of the motor 31 according to the hydraulic oil flow rate command value calculated by the flow rate command value calculation unit 41.

  The subtraction unit 43 calculates the difference between the rotation speed command value and the current rotation speed of the motor 31 calculated by the rotation speed calculation unit 47. The feedback control unit 44 determines the operation amount of the rotation speed of the motor 31 according to the difference. The duty calculator 45 calculates the duty ratio of the driving power for driving the motor 31 according to the operation amount determined by the feedback controller 44.

  The drive element determination unit 46 turns on and off the switching elements Q1 to Q6 according to the current electrical angle of the rotor of the motor 31 determined by the output signal of the position sensor 70 and the duty ratio calculated by the duty calculation unit 45. Generate a control signal. The drive element determination unit 46 controls the phase current flowing from the power supply 30 to each phase coil of the motor 31 by switching on and off the switching elements Q1 to Q6.

  In the following description, the switching elements Q <b> 1 to Q <b> 3 are high-side elements that turn on / off the connection between the U-phase, V-phase, and W-phase coils of the motor 31 and the power supply 30. The switching elements Q4 to Q6 are low-side elements that turn on and off the connection between the U-phase, V-phase, and W-phase coils of the motor 31 and the ground.

  The rotation speed calculation unit 47 calculates the rotation speed (that is, the rotation speed) of the motor 31 according to the change in the electrical angle determined by the output signal of the position sensor 70. The current sensor 72 detects the all-phase current of the motor 31 and outputs a current detection signal indicating the detected value. The temperature sensor 73 detects the temperature of the power unit 60 and outputs a temperature signal indicating the detected value.

  The determination unit 49 detects an abnormality that has occurred in the electrohydraulic power steering apparatus 1 according to the temperature signal, the current detection signal, the voltage of the power supply 30, and the rotation number of the motor 31 calculated by the rotation number calculation unit 47. The determination unit 49 generates a relay drive signal that drives the relay 80. When the determination unit 49 detects a predetermined abnormality, the determination unit 49 controls the relay 80 to stop the supply of current from the power supply 30 to the power unit 60.

  The determination unit 49 generates a stop signal for stopping the rotation of the motor 31 and / or a limit signal for limiting the rotation of the motor 31. The rotation speed command value calculation unit 42 stops and / or limits the rotation of the motor 31 according to the stop signal and / or the limit signal. The determination unit 49 also outputs a warning notifying the abnormality via the warning output unit 25 to the driver. The processing of the position sensor failure detection unit 48 will be described later.

  Next, control of the motor 31 by the control unit 10 will be described. FIG. 3 is an explanatory diagram of an example of motor control by the control unit 10. 3A shows a time chart of the on / off state of the ignition switch of the vehicle, FIG. 3B is a time chart of the control state of the electrohydraulic power steering apparatus 1, and FIG. These are time charts of the rotational speed of the motor 31.

When the ignition switch is turned on at time t0, the electrohydraulic power steering apparatus 1 rotates the motor 31 at a predetermined idling rotation until a predetermined time elapses or until the steering state is detected by the torque sensor 21 or the steering angle sensor 22. Start idling rotation control driven by number.
The idling rotation control is a control for smoothly assisting steering when the driver actually performs steering, for example, by raising the temperature of the oil by driving the pump 32. Therefore, normally, the idling rotational speed is set to a rotational speed lower than the rotational speed when steering is actually performed by the driver and steering assistance is performed.

  If steering by the driver is not performed when the idling rotation is completed at time t1, the control unit 10 stops the rotation of the motor 31. Thereafter, when steering is performed at time t2, the control unit 10 rotates the motor 31 at a rotational speed corresponding to the steering force, the steering angle, the vehicle speed, and the like.

  Thereafter, when the steering stops at time t3, the control unit 10 stops the rotation of the motor 31 again. In this way, the control unit 10 saves power consumption by driving the motor 31 only when steering assistance is necessary.

  FIG. 4 is an example of a state transition diagram for realizing the motor control shown in FIG. By turning on the ignition switch, the current state of the electrohydraulic power steering apparatus 1 is changed from the standby state ST0 to the idle rotation state ST1 in which the idling rotation control is performed. In the idle rotation state ST1, the motor 31 performs a predetermined idle rotation immediately after the operation starts.

  If the steering is not performed at the time when the idle rotation is finished after a predetermined time during which the idle rotation is performed, the current state transitions to the stop state ST2. In the stop state ST2, the motor 31 stops. If steering is performed at the time when idle rotation ends, the current state transitions to the normal control state ST3. In the normal control state ST3, the motor 31 rotates at a rotation speed corresponding to the steering force, the steering angle, the vehicle speed, and the like. Thereafter, if steering is performed in the stop state ST2, the current state transitions to the normal control state ST3. If the steering stops, the current state transitions to the stop state ST2.

  If an abnormality, that is, a failure occurs in the position sensor 70 in the idle rotation state ST1 and the normal control state ST3, the current state transitions to the fail safe mode ST4. In the fail safe mode ST4, the control unit 10 rotates the motor 31 by a control method different from the normal control called life extension control.

  When the position sensor 70 breaks down, the drive element determination unit 46 in FIG. 2 cannot acquire the accurate electrical angle of the current rotor of the motor 31. Therefore, in this case, the drive element determination unit 46 generates the phase current control signal by a control method different from that in the normal time.

  For example, it is assumed that when the position sensor 70 includes a hall sensor, an abnormality occurs in which the output of any one of the U-phase hall element, the V-phase hall element, and the W-phase hall element is fixed. In the fail safe mode ST4, the drive element determination unit 46 estimates the electrical angle of the rotor of the motor 31 based on the output change of the Hall element that is not abnormal, and generates a phase current control signal according to the estimated electrical angle.

  If steering is stopped while the motor 31 is being driven in the fail-safe mode ST4, the current state transitions to the stop state ST2. Further, when the ignition switch is turned off in the fail safe mode ST4, the current state transitions to the standby state ST0.

  FIG. 5 is an explanatory diagram of changes in the rotational speed when controlled by the state transition of FIG. Assume a case where an abnormality occurs in the position sensor 70 after idling rotation is stopped at time t1. Thereafter, the steering is performed at time t2, whereby the current state transitions to the normal control state ST3, and the rotation of the motor is started.

  At this time, if abnormality of the position sensor 70 is detected after the rotation of the motor 31 is started, the transition to the fail-safe mode ST4 is delayed. As a result, the rotation speed of the motor 31 is insufficient from the transition time t2 to the normal control state ST3 to the transition time t4 to the failsafe mode ST4. A dotted line 90 shows a graph of the original motor rotation speed, and a solid line 91 shows a graph of the motor rotation speed lowered due to the abnormality of the position sensor 70.

  As described above, in the case of the electrohydraulic power steering apparatus 1 that drives the motor 31 only when steering assistance is necessary, when the abnormality of the position sensor 70 is detected after the rotation of the motor 31 is started, each time the motor stops. A delay in steering assistance occurs.

  In order to solve this problem, the position sensor failure detection unit 48 shown in FIG. 2 detects an abnormality that has occurred in the position sensor 70 when the motor 31 is in a stationary state.

  The position sensor failure detection unit 48 detects the output state of the position sensor 70 in the stop state ST2. Hereinafter, the electrical angle of the rotor of the motor 31 measured from the output state of the position sensor 70 is referred to as “electrical angle A”.

  In addition, the position sensor failure detection unit 48 measures the electrical angle of the rotor of the motor 31 by other measurement means different from the position sensor 70 in the stop state ST2. A value measured by this measuring means is expressed as “electrical angle B”. An example of this measuring means for measuring the electrical angle B will be described later.

  The position sensor 70 and the measurement means for measuring the electrical angle B are examples of the first measurement unit and the second measurement unit, respectively. The position sensor failure detection unit 48 is an example of an abnormality detection unit. The electrical angle A and the electrical angle B are examples of the first measurement angle and the second measurement angle, respectively.

  The position sensor failure detection unit 48 estimates the output state of the position sensor 70 from the electrical angle B. For example, the position sensor failure detection unit 48 may estimate that the output state of the position sensor 70 is the same as the expected output state when the rotor of the motor 31 is at the electrical angle B. The position sensor failure detection unit 48 compares the output state estimated from the electrical angle B with the actual output state of the position sensor 70, and if they are different, the electrical angle A or the position sensor 70 is abnormal due to the position sensor 70. Is detected.

  The position sensor failure detection unit 48 outputs an abnormality detection signal indicating that an abnormality of the electrical angle A or the position sensor 70 has been detected to the drive element determination unit 46 and the rotation speed calculation unit 47. The position sensor failure detection unit 48 measures the electrical angle A, compares the electrical angle A and the electrical angle B, and when the electrical angle A and the electrical angle B are different, An abnormality may be detected.

  When the abnormality detection signal is received, the drive element determination unit 46 and the rotation speed calculation unit 47 operate in the fail safe mode ST4. In the fail-safe mode ST4, the drive element determination unit 46 and the rotation speed calculation unit 47 generate a phase current control signal and calculate the rotation speed by a predetermined life extension control process.

  FIG. 6 is a state transition diagram of a first example of motor control. In the state transition diagram of FIG. 4, an edge for transitioning to the fail-safe mode ST4 when a position sensor failure is detected in the stop state ST2 is added.

  That is, when a failure of the position sensor 70 is detected in the stop state ST2, the current state directly transitions to the fail-safe mode ST4 when the steering assistance is necessary. In other words, when a failure of the position sensor 70 is detected in the stop state ST2, the control unit 10 directly starts driving the motor 31 by life extension control when the steering assistance is necessary.

  FIG. 7 is an explanatory diagram of changes in the rotation speed when controlled by the state transition of FIG. Assume a case where an abnormality occurs in the position sensor 70 after idling rotation stops at time t2 and transitions to the stop state ST2.

  The position sensor failure detection unit 48 acquires the output state and the electrical angle B of the position sensor 70 in the stop state ST2, and detects an abnormality of the position sensor 70. Thereafter, when steering assistance is required at time t5, the current state directly transitions to the fail safe mode ST4.

  As a result, the control unit 10 can drive the motor 31 at a rotational speed similar to the originally planned rotational speed immediately after the rotation of the motor 31 starts. For this reason, since the rotational speed of the motor 31 is not insufficient from the start of rotation, there is no delay in steering assistance.

  As described above, according to the present embodiment, in the case of the electrohydraulic power steering apparatus 1 that drives the motor 31 only when the steering assistance is necessary, even if the position sensor 70 is abnormal while the motor is stopped, the steering is performed. Assistance delay can be prevented.

  Hereinafter, an example in which the position sensor 70 includes a hall sensor will be described. FIG. 8 is an explanatory diagram of a position sensor 70 including a hall sensor. Reference numerals 34 and 35 schematically indicate a rotor and a stator of the motor 31, respectively. Reference numerals 34S and 34N are an S pole and an N pole of the rotor 34, respectively. Reference numerals 35U, 35V, and 35W denote a U-phase magnetic pole, a V-phase magnetic pole, and a W-phase magnetic pole of the stator 35, respectively. Reference numerals 36U, 36V, and 36W denote a U-phase coil, a V-phase coil, and a W-phase coil of the stator 35, respectively.

  The position sensor 70 includes a U-phase Hall element 71U, a V-phase Hall element 71V, and a W-phase Hall element 71W for detecting the position of the magnetic pole of the rotor 34. The U-phase Hall element 71U, the V-phase Hall element 71V, and the W-phase Hall element 71W may be collectively referred to as “Hall element 71”. Each Hall element 71 detects the type of magnetic pole of the rotor 34 at an electrical angle that is 120 degrees apart. For example, in one embodiment, an “H” level is output when approaching the S pole 34S of the rotor 34 corresponding to the Hall element 71, and an “L” level is output when approaching the N pole 34N.

  In one embodiment, the direction of the forward rotation of the rotor 34 is determined to be counterclockwise, and the electrical angle of the rotor when the magnetic pole close to the U-phase Hall element 71U changes from the N pole 34N to the S pole 34S is determined. It is defined as “0” degree. FIG. 8 shows the state of the rotor having an electrical angle of “0” when the rotational direction and phase of the electrical angle are determined in this way. FIG. 9 shows an example of the relationship between the Hall sensor output and the electrical angle in the same case.

  For example, the U-phase Hall element outputs an “H” level when the electrical angle is 0 to 180 degrees, and outputs an “L” level when the electrical angle is 180 to 360 degrees. The V-phase Hall element outputs an “H” level when the electrical angle is 120 to 300 degrees, and outputs an “L” level when the electrical angles are 0 to 120 degrees and 300 to 360 degrees. The W-phase Hall element outputs an “H” level when the electrical angle is 0 to 60 degrees and 240 to 360 degrees, and outputs an “L” level when the electrical angle is 60 to 240 degrees.

  In the case of this example, the position sensor failure detection unit 48 outputs the electrical signal when the outputs of the U-phase Hall element, V-phase Hall element, and W-phase Hall element are “H” level, “L” level, and “H” level, respectively. It is determined that the angle is 0 to 60 degrees. The position sensor failure detection unit 48 has an electrical angle of 60 when the outputs of the U-phase Hall element, the V-phase Hall element, and the W-phase Hall element are “H” level, “L” level, and “L” level, respectively. It is determined to be ˜120 degrees. Further, the position sensor failure detection unit 48 has an electrical angle of 120 when the outputs of the U-phase Hall element, the V-phase Hall element, and the W-phase Hall element are “H” level, “H” level, and “L” level, respectively. It is determined that the angle is ˜180 degrees.

  Similarly, the position sensor failure detection unit 48 has an electrical angle when the outputs of the U-phase Hall element, the V-phase Hall element, and the W-phase Hall element are “L” level, “H” level, and “L” level, respectively. It is determined that the angle is 180 to 240 degrees. The position sensor failure detection unit 48 has an electrical angle of 240 when the outputs of the U-phase Hall element, the V-phase Hall element, and the W-phase Hall element are “L” level, “H” level, and “H” level, respectively. It is determined to be ˜300 degrees. The position sensor failure detection unit 48 has an electrical angle of 300 when the outputs of the U-phase Hall element, the V-phase Hall element, and the W-phase Hall element are “L” level, “L” level, and “H” level, respectively. It is determined to be ~ 360 degrees.

  Please refer to FIG. The angular position at which the Hall element 71 detects the magnetic poles of the rotor may be different from the directions of the magnetic poles 35U, 35V and 35W of the stator 35. An angular position at which the Hall element 71 detects the magnetic pole of the rotor may be referred to as a “mounting angle” of the Hall element. In FIG. 8, reference numeral 38 indicates the mounting angle of the U-phase Hall element 71U.

  In the example of FIG. 8, the mounting angle of the U-phase Hall element 71U, the V-phase Hall element 71V, and the W-phase Hall element 71W is a deviation angle Ah from the direction of the U-phase magnetic pole 35U, the V-phase magnetic pole 35V, and the W-phase magnetic pole 35W. Just advanced. For example, in the case of a delta connection motor, the deviation angle Ah may be 30 degrees, and in the case of a Y connection motor, the deviation angle Ah may be 0 degrees. The shift angle Ah may be another angle.

  The position sensor failure detection unit 48 detects an abnormality of the position sensor 70 when the output state of the Hall element 71 is different from the output state of the Hall element 71 estimated from the electrical angle B measured by other measuring means. To do.

  When the output state of the Hall element 71 and the output state estimated from the electrical angle B are different, the position sensor failure detection unit 48 assumes that the output state estimated from the electrical angle B is correct, and the U-phase Hall An element that outputs an erroneous signal is selected from the element 71U, the V-phase hall element 71V, and the W-phase hall element 71V. The position sensor failure detection unit 48 generates a failure element specifying signal that specifies the selected element as a failure element.

  The position sensor failure detection unit 48 outputs a failure element specifying signal to the rotation speed calculation unit 47 and the drive element determination unit 46 together with an abnormality detection signal indicating that an abnormality of the position sensor 70 has been detected. By receiving the abnormality detection signal, the rotation speed calculation unit 47 and the drive element determination unit 46 operate in the fail safe mode ST4.

  In the fail safe mode ST4, the rotation speed calculation unit 47 calculates the rotation speed of the motor 31 using, for example, an output signal of an element other than the failed element. In addition, the drive element determination unit 46 estimates the electrical angle of the rotor of the motor 31 according to, for example, the rotation period of the motor 31 determined using the output signal of the element other than the failed element and the output signal of the element other than the failed element. To do. A phase current control signal is generated according to the estimated electrical angle.

  Next, an example of a failure detection method when a hall sensor is used as the position sensor 70 will be described. FIG. 10 is an explanatory diagram of a first example of processing of the failure detection method. In other embodiments, the following operations AA to AN may be steps.

  In operation AA, the position sensor failure detection unit 48 substitutes a value “0” for the variable i. In operation AB, the position sensor failure detection unit 48 determines whether or not the variable i is smaller than a predetermined number N. When the variable i is smaller than the predetermined number N (operation AB: Y), the processing proceeds to operation AC. If the variable i is not smaller than the predetermined number N (operation AB: N), the process proceeds to operation AL.

  In operation AC, the position sensor failure detection unit 48 measures the output state of the hall sensor 70. The measured output state of the hall sensor 70 is referred to as “output state A”. In operation AD, the electrical angle A is obtained from the output state of the hall sensor 70. The determination of the electrical angle A may be performed by the position sensor 70, and the drive element determination unit 46 that uses the measurement result of the Hall sensor 70 may be performed by the rotation speed calculation unit 47. The position sensor failure detection unit 48 may obtain the electrical angle A.

  Note that the operations AC and AD may be processing performed when in the normal control state ST3. The drive element determination unit 46 may generate a phase current control signal according to the electrical angle A determined by the operation AD. Further, the rotational speed calculation unit 47 may calculate the rotational speed of the motor 31 in accordance with the change in the electrical angle A determined by the operation AD. Further, as the abnormality detection process, determination of the electrical angle A in the operation AD may be omitted.

  In operation AE, the measurement means other than the hall sensor 70 measures the electrical angle B while the motor 31 is stationary. In operation AF, the position sensor failure detection unit 48 estimates an output state that is expected to be output from the hall sensor 70 based on the electrical angle B. The output state estimated based on the electrical angle B is referred to as “output state B”.

  In operation AG, the position sensor failure detection unit 48 compares the output state A and the output state B. When the output state A and the output state B are equal (operation AG: Y), the process proceeds to operation AH. When the output state A and the output state B are different (operation AG: N), the process proceeds to operation AI. In operation AG, the position sensor failure detection unit 48 may compare the electrical angle A with the electrical angle B. If the electrical angle A is equal to the electrical angle B (operation AG: Y), the processing may shift to operation AH. When the electrical angle A and the electrical angle B are different (operation AG: N), the processing may shift to operation AI.

  In operation AH, the position sensor failure detection unit 48 assigns the value “normal” to the i-th state variable status [i], and then the process proceeds to operation AJ.

  In operation AI, the position sensor failure detection unit 48 substitutes the value “abnormal” for the i-th state variable status [i]. Thereafter, the process proceeds to operation AJ.

  In operation AJ, the position sensor failure detection unit 48 increases the value of the variable i by one. In operation AK, the position sensor failure detection unit 48 rotates the motor by a predetermined rotation angle that causes a change in the output state of the Hall sensor, thereby acquiring the rotation position of the motor and then the detection signal of the Hall sensor 70. Position it at an electrical angle and let it stand still.

  In the electro-hydraulic power steering apparatus 1, the rack 5 is not directly driven by the power of the motor 31 as described above, and the driving force applied to the steering wheel when the driver steers is driven by the motor. Assist with the power generated by the hydraulic pump. For this reason, unless the driver performs a steering operation, even if the motor is driven in operation AK, steering is not performed regardless of the driver's intention.

  In operation AK, the position sensor failure detection unit 48 outputs an instruction signal for positioning the rotational position of the motor 31 to the electrical angle for obtaining the detection signal of the hall sensor 70 to the drive element determination unit 46.

  In order to generate this instruction signal, for example, the position sensor failure detection unit 48 determines the combination and order of electrical angles in which the combinations of output values of the U-phase Hall element 71U, the V-phase Hall element 71V, and the W-phase Hall element 71W are different from each other. It is determined in advance.

  For example, an electrical angle of 1 to 60 degrees is A1, an electrical angle of 61 to 120 degrees is A2, an electrical angle of 121 to 120 degrees is A3, an electrical angle of 181 to 240 degrees is A4, and an electrical angle is 241 to 300 degrees. An electrical angle of A5, 301 to 360 degrees is denoted as A6. The position sensor failure detection unit 48 stores a combination of electrical angles including predetermined electrical angles A1 to A6. The combinations (U, V, W) of the output values of the hall elements 71 at the electrical angles A1 to A6 are (H, L, H), (H, L, L), (H, H, L), respectively. (L, H, L), (L, H, H) and (L, L, H), which are different from each other.

  The position sensor failure detection unit 48 stores a predetermined order between the electrical angles A1 to A6. In this order, the position sensor failure detection unit 48 determines the electrical angle specified next to the electrical angle A measured in operation AC as the electrical angle from which the detection signal of the hall sensor 70 is acquired next.

  After operation AK, the process returns to operation AB.

  In operation AL, the position sensor failure detection unit 48 determines whether any value of the state variable status [i] (i is a natural number of 0 to (N−1)) is “abnormal”. If none of the values of the state variable status [i] is “abnormal” (operation AL: N), the processing shifts to the operation AM. When any value of the state variable status [i] is “abnormal” (operation AL: Y), the processing shifts to the operation AN.

  In operation AM, the position sensor failure detection unit 48 determines that the electrical angle A measured by the output signal of the hall sensor 70 is not abnormal. As a result, the rotation speed calculation unit 47 and the drive element determination unit 46 operate in the normal control state ST3 when performing steering assistance. Thereafter, the process ends.

  In operation AN, the position sensor failure detection unit 48 determines that the electrical angle A measured by the output signal of the hall sensor 70 is abnormal. As a result, the rotation speed calculation unit 47 and the drive element determination unit 46 operate in the fail safe mode ST4 when performing steering assist. Thereafter, the process ends.

  According to the present embodiment, the position sensor failure detection unit 48 detects an abnormality of the electrical angle measured by the output of the Hall sensor 70 based on the detection results of the sensors at a predetermined number N of electrical angles. Since the detection result of one electrical angle cannot detect all the failure details that occur in the Hall sensor 70, it is possible to increase the number of failure details that can be detected by designating the predetermined number N to be larger than 1. It becomes.

  Table 1 below shows the details of failure that can be detected at each electrical angle.

  For example, in the electric angle range of 1 to 60 degrees, the failure in which the U-phase Hall element 71U and the W-phase Hall element 71W are fixed to the L level side can be detected, but the failure to be fixed to the H level side cannot be detected. Further, although the failure that the V-phase Hall element 71V is fixed to the H level side can be detected, the failure that is fixed to the L level side cannot be detected.

  Similarly, in the electrical angle range of 61 degrees to 120 degrees, a failure in which the U-phase Hall element 71U is fixed to the L level side can be detected, but a failure to be fixed in the H level side cannot be detected. Further, it is possible to detect a failure in which the V-phase Hall element 71V and the W-phase Hall element 71W are fixed to the H level side, but it is not possible to detect a failure to be fixed to the L level side.

  From Table 1, it is possible to detect all the failure contents that can occur in the Hall sensor 70 by detecting the abnormality of the Hall sensor 70 based on the detection results of the sensors at four or more electrical angles. Therefore, the predetermined number N is preferably larger than “3”.

  Next, an example of processing of another detection method is shown. FIG. 11 is an explanatory diagram of a second example of the process of the failure detection method. In other embodiments, the following operations AA to AG and AP to AT may be steps.

  Each process of operation AA and operation AF is the same as each process demonstrated with reference to FIG. In operation AG, the position sensor failure detection unit 48 compares the output state A and the output state B. When the output state A is equal to the output state B (operation AG: Y), the process proceeds to operation AQ. When the output state A and the output state B are different (operation AG: N), the process proceeds to operation AO. Similarly to the above, in operation AG, the position sensor failure detection unit 48 may compare the electrical angle A and the electrical angle B instead of comparing the output state A and the output state B.

  In operation AO, the position sensor failure detection unit 48 determines that the electrical angle A measured by the output signal of the hall sensor 70 is abnormal. In operation AP, the rotation speed calculation unit 47 and the drive element determination unit 46 operate in the fail safe mode ST4 when performing steering assist. Thereafter, the process ends.

  The state in which the output state A and the output state B are determined to be equal in operation AG (operation AG: Y) is an undetermined state in which the position sensor failure detection unit 48 cannot determine whether or not the electrical angle A is abnormal. In operation AQ, the position sensor failure detection unit 48 increases the value of the variable i by one. In operation AR, the position sensor failure detection unit 48 positions the rotation position of the motor to the electrical angle at which the detection signal of the hall sensor 70 is next acquired, and stops it. After operation AR, the process returns to operation AB.

  Next, processing after operation AS will be described. The position sensor failure detection unit 48 determines that the electrical angle A is normal in operation AS because the abnormality of the electrical angle A is not detected in the abnormality detection process for N electrical angles. In operation AT, the rotation speed calculation unit 47 and the drive element determination unit 46 operate in the normal control state ST3 when performing steering assist. Thereafter, the process ends.

  According to the present embodiment, the abnormality detection process is terminated as soon as an abnormality is detected in operation AO. Therefore, the processing amount of the abnormality detection process can be reduced, and the power consumption can be reduced.

  Next, an example of measuring means for measuring the electrical angle B will be described. In this example, the electrical angle of the rotor is detected by utilizing the fact that the current flowing through the phase coil differs depending on the relationship between the direction of the magnetic field generated by the phase coil and the direction of the magnetic pole of the rotor.

  That is, when the direction of the magnetic field generated by the coil of the stator magnetic pole is closer to the direction of the rotor magnetic pole, the combination of the magnetic fields generated by both becomes larger, so the stator core is more likely to be magnetically saturated. For this reason, since the inductance of the phase coil becomes smaller and the current easily flows, the current change of the phase current flowing at the start of excitation, that is, the drive current becomes larger.

  The position sensor failure detection unit 48 outputs an instruction signal that causes the drive element determination unit 46 to drive the switching elements Q1 to Q6 so that the phase coils of the motor 31 sequentially generate magnetic fluxes in the directions of different electrical angles. .

  Table 2 below shows examples of driving patterns of the switching elements Q1 to Q6 for generating magnetic fluxes in the directions of six different electrical angles.

  In drive pattern 1, U-phase high-side element Q1, V-phase high-side element Q2, and W-phase low-side element Q6 are turned off, and U-phase low-side element Q4, V-phase low-side element Q5, and W-phase high-side element Q3 are turned on. To.

  In drive pattern 2, U-phase high-side element Q1, V-phase high-side element Q2, and W-phase low-side element Q6 are turned on, and U-phase low-side element Q4, V-phase low-side element Q5, and W-phase high-side element Q3 are turned off. To.

  In drive pattern 3, U-phase high-side element Q1, V-phase low-side element Q5, and W-phase high-side element Q3 are turned on, and U-phase low-side element Q4, V-phase high-side element Q2, and W-phase low-side element Q6 are turned off. To.

  In drive pattern 4, U-phase high-side element Q1, V-phase low-side element Q5, and W-phase high-low side element Q3 are turned off, and U-phase low-side element Q4, V-phase high-side element Q2, and W-phase low-side element Q6 are turned on. To.

  For example, in drive pattern 5, U-phase high-side element Q1, V-phase low-side element Q5, and W-phase low-side element Q6 are turned on, and U-phase low-side element Q4, V-phase high-side element Q2, and W-phase high-side element Q3 are turned on. Is turned off.

  Further, for example, in the drive pattern 6, the U-phase high-side element Q1, the V-phase low-side element Q5, and the W-phase low-side element Q6 are turned off, and the U-phase low-side element Q4, the V-phase high-side element Q2, and the W-phase high-side element Q3 Turn on the.

  Next, the magnetic flux generated in the stator of the motor 31 in the drive pattern of the switching elements Q1 to Q6 will be described. In the following description, FIG. 8 is referred to as an explanatory diagram illustrating the configuration of the motor 31. Moreover, the following description demonstrates the example in which the motor 31 has the stator coils 36U, 36V, and 36W connected by the delta connection. However, the motor 31 may be a Y-connected motor.

  FIG. 12 is an explanatory diagram of currents flowing through the stator coils 36U, 36V and 36W connected by the delta connection. Reference numeral 37U is a U terminal of the motor 31 to which a connection point between the U-phase high-side element Q1 and the U-phase low-side element Q4 is connected. Similarly, reference numeral 37V is a V terminal to which a connection point between the V-phase high-side element Q2 and the V-phase low-side element Q5 is connected. Reference numeral 37W is a V terminal to which a connection point of the W-phase high-side element Q3 and the W-phase low-side element Q6 is connected.

  When U-phase high-side element Q1, V-phase high-side element Q2 and W-phase high-side element Q3 are turned on, phase currents flow into U terminal 37U, V terminal 37V and W terminal 37W, respectively. On the other hand, when the U-phase low-side element Q4, the V-phase low-side element Q5, and the W-phase low-side element Q6 are turned on, phase currents flow from the U terminal 37U, the V terminal 37V, and the W terminal 37W, respectively. FIG. 12 shows the phase current when the W-phase high-side element Q3 is in the on state and the U-phase low-side terminal Q4 and the V-phase low-side terminal Q5 are in the on-state. The phase current of W-phase coil 36W flows from W-phase terminal 37W to U-phase terminal 37U. The phase current of the V-phase coil 36V flows from the W-phase terminal 37W to the V-phase terminal 37V.

  13A to 13F show the relationship between the direction of each coil current in the driving patterns 1 to 6 in Table 2 and the polarities of the U-phase magnetic pole 35U, the V-phase magnetic pole 35V, and the W-phase magnetic pole 35W. It is explanatory drawing which shows an example. The relationship between the direction of each coil current and the polarity of each magnetic pole may vary depending on the configuration of the motor 31. As shown in the figure, the U-phase coil 36U has a U-phase magnetic pole 35U that is N-pole when a phase current flows from the U terminal 37U to the V-terminal 37V, and a U-phase when the phase current flows from the V-terminal 37V to the U-terminal 37U. The magnetic pole 35U is wound so as to be an S pole. In the V-phase coil 36V, when the phase current flows from the V terminal 37V to the W terminal 37W, the V-phase magnetic pole 35V becomes the N pole, and when the phase current flows from the W terminal 37W to the V terminal 37V, the V-phase magnetic pole 35V becomes S. It is wound to become a pole. In the W-phase coil 36W, the W-phase magnetic pole 35W becomes the N pole when the phase current flows from the W terminal 37W to the U terminal 37U, and the W-phase magnetic pole 35W becomes S when the phase current flows from the U terminal 37U to the W terminal 37W. It is wound to become a pole.

  As a result, as shown in FIG. 13A, in the case of the drive pattern 1, the W-phase magnetic pole 35W becomes the N pole and the V-phase magnetic pole 36V becomes the S pole. As shown in FIG. 13B, in the case of the drive pattern 2, the V-phase magnetic pole 35V is an N pole and the W-phase magnetic pole 36W is an S pole. As shown in FIG. 13C, in the case of the drive pattern 3, the U-phase magnetic pole 35U is an N pole and the V-phase magnetic pole 36V is an S pole.

  As shown in FIG. 13D, in the case of the drive pattern 4, the V-phase magnetic pole 35V is an N pole and the U-phase magnetic pole 36U is an S pole. As shown in FIG. 13E, in the case of the drive pattern 5, the U-phase magnetic pole 35U is an N pole and the W-phase magnetic pole 36W is an S pole. As shown in FIG. 13F, in the case of the drive pattern 6, the W-phase magnetic pole 35W is an N pole and the U-phase magnetic pole 36U is an S pole.

  The position sensor failure detection unit 48 detects a change in the drive current of the motor 31 detected by the current sensor 72 while a drive current is passed through the phase coil by each of the drive patterns 1 to 6. The position sensor failure detection unit 48 determines the electrical angle B according to the magnitude relationship of the change rate of the drive current at the start of excitation in each drive pattern 1-6.

  14A to 14C are time charts of drive signals for the U-phase low-side element Q4, the V-phase low-side element Q5, and the W-phase low-side element Q6. FIG. 14D is a time chart of the drive current of the motor 31 detected by the current sensor 72. At times t1, t2,..., T6, driving currents of driving patterns 1, 2,. For example, the position sensor failure detection unit 48 may determine that the change rate of the drive current is larger as the time until the value of the drive current reaches a predetermined threshold is shorter. For example, a time Δt shown in (D) of FIG. 14 indicates a time from the time t1 when the drive pattern 1 is applied until the value of the drive current reaches a predetermined threshold value Vt.

  The position sensor failure detection unit 48 also determines the time Δt from the time when the drive patterns 2 to 6 are applied until the value of the drive current reaches the predetermined threshold value Vt at other times t2 to t6. The position sensor failure detection unit 48 determines the magnitude of the change rate of the drive current in each drive pattern according to the length of Δt determined in each drive pattern. For example, the position sensor failure detection unit 48 may determine that the change rate of the drive current is larger as the drive current changed during the predetermined period is larger.

  When the electrical angle of the rotor is a certain angle, the magnitude relationship of the change rate of the drive current in each drive pattern depends on the difference in the motor configuration such as the coil coupling method and the coil winding direction, and the Hall element 71. It depends on the mounting angle. In the following description, the motor 31 is a delta-connected coil, the deviation angle Ah between the mounting angle of the Hall element and the direction of the stator magnetic pole is 30 °, and the direction of the coil winding is from (A) to FIG. An example of a method for determining the electrical angle B in the case shown in FIG. 13F will be described.

  The position sensor failure detection unit 48 determines the drive pattern with the largest change in drive current and the second largest drive pattern. The position sensor failure detection unit 48 determines the electrical angle B according to the combination of the drive pattern with the largest change in drive current and the second largest drive pattern. For example, the position sensor failure detection unit 48 stores a predetermined correspondence relationship between each combination of the electrical angle B and the drive pattern with the largest change in drive current and the second largest drive pattern. Table 3 below is a table showing this correspondence.

  For example, in Table 3, when the drive current change is the largest in the drive pattern 2 and the drive current change is the second largest in the drive pattern 5, the electrical angle B of the rotor is in the range of 0 ° to 30 °. It is shown that. Further, for example, Table 3 shows that when the drive current change is the largest in the drive pattern 2 and the drive current change is the second largest in the drive pattern 4, the electrical angle B of the rotor is in the range of 30 ° to 60 °. It shows that there is.

  The position sensor failure detection unit 48 determines a combination of drive patterns in which the largest change in drive current and the second largest change in drive current are detected, and represents an electrical angle corresponding to this combination as an electrical angle B. Read from 3.

  For example, when the drive current changes as shown in FIG. 14D, the drive current changes most in the drive pattern 3 and the drive current changes second most in the drive pattern 1. That is, FIG. 15 shows the state of the electrical angle B of the rotor where such a change in drive current occurs. The electrical angle B of the rotor is in the range of 210 ° to 240 °. In this state, when the U-phase magnetic pole 35U is an N pole and the V-phase magnetic pole 35V is an S pole, the direction of the magnetic field generated by the stator magnetic pole coil and the direction of the rotor magnetic pole are closest. For this reason, the drive current changes most in the drive pattern 3. When the W-phase magnetic pole 35W is an N pole and the V-phase magnetic pole 35V is an S pole, the direction of the magnetic field generated by the stator magnetic pole coil and the direction of the rotor magnetic pole are the second closest. For this reason, the drive current changes most greatly in the drive pattern 1. The position sensor failure detection unit 48 determines that the electrical angle B is in the range of 210 ° to 240 ° according to Table 3.

  The magnetic fluxes generated by the drive patterns 1 and 2 are separated by 60 degrees or more in the direction of the magnetic flux. The same applies to the magnetic fluxes generated by the driving patterns 2 and 3, the magnetic fluxes generated by the driving patterns 3 and 4, respectively, the magnetic fluxes generated by the driving patterns 4 and 5, respectively, and the magnetic fluxes generated by the driving patterns 5 and 6, respectively. is there.

  Therefore, when the position sensor failure detection unit 48 changes the drive pattern in the order of the drive patterns 1, 2, 3, 4, 5 and 6, the amount of change in the direction of the two consecutive magnetic fluxes generated is 60 degrees. Bigger than. By applying the drive patterns in this order, the motor 31 is less likely to rotate than in normal rotation control.

  Furthermore, the magnetic flux directions generated by the drive patterns 1 and 2, the magnetic fluxes generated by the drive patterns 3 and 4, and the magnetic fluxes generated by the drive patterns 5 and 6, respectively, differ by 180 degrees. Thus, by changing the direction of the two consecutively generated magnetic fluxes by 180 degrees, the motor 31 becomes more difficult to rotate.

  Next, another example of control of the motor 31 by the control unit 10 will be described. From the viewpoint of saving the power consumption of the motor 31, it is desirable that the number of occurrences of the process of rotating the motor 31 or the process of changing the rotational position of the motor 31 is small. Moreover, once it is determined that the position sensor 70 is normal, it is considered that the frequency of occurrence of failure immediately is low.

  Therefore, in the embodiment described below, after the electrohydraulic power steering apparatus 1 starts to operate, the control unit 10 performs the abnormality detection process described with reference to FIG. 10 or FIG. When the abnormality of the position sensor 70 is not detected in the abnormality detection process shown in FIG. 10 or FIG. 11, the control unit 10 subsequently displays the state shown in FIG. 10 or FIG. 11 when the electrohydraulic power steering apparatus 1 enters the stop state ST2. The abnormality detection process of the position sensor 70 is performed by an abnormality detection process simpler than the abnormality detection process shown in FIG.

  In the simple abnormality detection process, the position sensor failure detection unit 48 detects an abnormality of the Hall sensor 70 based on the detection results of the sensors at a smaller number of electrical angles than the predetermined number N. In this way, by reducing the number of electrical angles at which the abnormality detection processing of the Hall sensor 70 is performed, the number of times of changing the rotational position of the rotor of the motor 31 is reduced, and the power consumption of the motor 31 is saved.

  For example, in a simple abnormality detection process, the position sensor failure detection unit 48 detects an abnormality of the hall sensor 70 based on the detection result of the sensor at one electrical angle. In this case, the position sensor failure detection unit 48 does not change the rotational position of the rotor of the motor 31.

  FIG. 16 is an explanatory diagram of simple failure detection processing. In other embodiments, the following operations BA to BG may be steps. In operation BA, the position sensor failure detection unit 48 measures the output state of the hall sensor 70. The measured output state of the hall sensor 70 is referred to as “output state A”.

  In operation BB, the electrical angle A is obtained from the output state of the hall sensor 70. The determination of the electrical angle A may be performed by the position sensor 70, and the drive element determination unit 46 that uses the measurement result of the Hall sensor 70 may be performed by the rotation speed calculation unit 47. The position sensor failure detection unit 48 may obtain the electrical angle A. Note that operations BA and BB may be processes performed when in the normal control state ST3. The drive element determination unit 46 may generate a phase current control signal according to the electrical angle A determined in operation BB. Further, the rotation speed calculation unit 47 may calculate the rotation speed of the motor 31 in accordance with the change in the electrical angle A determined in operation BB. Further, as the abnormality detection process, the determination of the electrical angle A in the operation BB may be omitted.

  In operation BC, other measurement means other than the hall sensor 70 measures the electrical angle B while the motor 31 is stationary. In operation BD, the position sensor failure detection unit 48 estimates the output state B scheduled to be output from the hall sensor 70 based on the electrical angle B.

  In operation BE, the position sensor failure detection unit 48 compares the output state A and the output state B. When the output state A and the output state B are equal (operation BE: Y), the process proceeds to operation BF. When the output state A and the output state B are different (operation BE: N), the process proceeds to operation BG. In operation BE, the position sensor failure detection unit 48 may compare the electrical angle A and the electrical angle B instead of comparing the output state A and the output state B.

  In operation BF, the position sensor failure detection unit 48 determines that the electrical angle A measured by the output signal of the hall sensor 70 is not abnormal. As a result, the rotation speed calculation unit 47 and the drive element determination unit 46 operate in the normal control state ST3 when performing steering assistance. In operation BG, the position sensor failure detection unit 48 determines that the electrical angle A measured by the output signal of the hall sensor 70 is abnormal. As a result, the rotation speed calculation unit 47 and the drive element determination unit 46 operate in the fail safe mode ST4 when performing steering assist. Thereafter, the process ends.

  FIG. 17 shows a state transition diagram of a third example of motor control when the above-described simple abnormality detection process is performed. By turning on the ignition switch, the current state of the electro-hydraulic power steering device 1 transitions from the standby state ST0 to the temporary stop state ST5. In the stop state ST5, the motor 31 stops. In the stop state ST5, the abnormality detection process shown in FIG. 10 or FIG. 11 is performed. When the abnormality detection process ends, the current state transitions to the idle rotation state ST1. In the idle rotation state ST1, the motor 31 performs idle rotation.

  If the steering is not performed at the time when the idle rotation is finished after a predetermined time during which the idle rotation is performed, the current state transitions to the stop state ST2. In the stop state ST2, the motor 31 stops. In the stop state ST2, a simple abnormality detection process shown in FIG. 16 is performed.

  If steering is performed at the time when idle rotation ends, the current state transitions to the normal control state ST3. In the normal control state ST3, the motor 31 rotates at a rotation speed corresponding to the steering force, the steering angle, the vehicle speed, and the like. Thereafter, if steering is performed in the stop state ST2, the current state transitions to the normal control state ST3. If the steering stops, the current state transitions to the stop state ST2.

  When an abnormality of the hall sensor 70, that is, a failure is detected in the normal control state ST3, the current state transitions to the fail safe mode ST4. In addition, when a failure of the hall sensor 70 is detected in the stop state ST2, the current state directly transitions to the fail safe mode ST4 when the steering assist is necessary thereafter.

  In addition, when a failure of the hall sensor 70 is detected in the stop state ST5, the control unit 10 performs idling rotation in the fail safe mode. If the steering stops while driving the motor 31 in the fail safe mode ST4, the current state transitions to the stopped state ST2. Further, when the ignition switch is turned off in the fail safe mode ST4, the current state transitions to the standby state ST0.

  18A to 18C are explanatory diagrams of motor control by the state transition of FIG. 18A shows a time chart of the on / off state of the ignition switch of the vehicle, FIG. 18B is a time chart of the state of the electrohydraulic power steering apparatus 1, and FIG. 3 is a time chart of the rotational speed of a motor 31.

  When the ignition switch is switched on at time t0, the state transits to the stop state ST5. During this time, the motor 31 stops. In the stop state ST5, the control unit 10 performs the abnormality detection process shown in FIG.

  Thereafter, the current state transitions to the idle rotation state ST1 at time t1. When abnormality of the hall sensor 70 is detected in the stop state ST5, the control unit 10 performs idle rotation in the fail safe mode. When the abnormality of the hall sensor 70 is not detected, the control unit 10 performs normal idle rotation.

  At time t2, the current state transitions to the stopped state ST2. In the stop state ST2, the motor 31 stops. In the stop state ST5, the control unit 10 performs a simple abnormality detection process shown in FIG. When an abnormality of the hall sensor 70 is detected by a simple abnormality detection process, when it becomes necessary to assist steering at time t3, the current state directly transits to the fail safe mode ST4. As a result, the motor 31 is driven by life extension control.

  If the abnormality of the hall sensor 70 is not detected by the simple abnormality detection process, the current state transitions to the normal control state ST3 when the steering assist is required at time t3.

  According to the present embodiment, after the electrohydraulic power steering apparatus 1 starts operating, the abnormality detection process of the hall sensor 70 is performed in the abnormality detection process shown in FIG. 10 or FIG. The abnormality detection of the hall sensor 70 is performed with a few simple abnormality detection processes. For this reason, the present embodiment can save the power consumption of the motor 31 while achieving the object of early detection of abnormality of the Hall sensor 70.

DESCRIPTION OF SYMBOLS 1 Electrohydraulic power steering apparatus 2 Steering wheel 3 Column shaft 4 Front wheel 5 Rack 6 Pinion 30 Power supply 33 Power cylinder 46 Drive element determination part 48 Position sensor failure detection part 70 Position sensor 72 Current sensor

Claims (6)

A first measuring unit for measuring an electrical angle of a rotor of a synchronous motor from output states of a plurality of Hall sensors;
A second measuring unit for measuring the electrical angle by a method different from the Hall sensor;
When the synchronous motor is in a stationary state, the output state of the plurality of Hall sensors is estimated from the electrical angle measured by the second measurement unit, and the estimation result is compared with the output state measured by the first measurement unit. Accordingly, an abnormality detection unit that performs an abnormality detection process for detecting that there is an abnormality in the electrical angle output by the first measurement unit;
A motor abnormality detection device comprising:   When the abnormality detection unit detects that the abnormality detection process is in an undetermined state that cannot be determined to be normal or abnormal, the rotor detects a predetermined electrical angle that causes a change in the output state of the Hall sensor. The abnormality detection apparatus according to claim 1, wherein an additional abnormality detection process is performed in which the abnormality detection process is performed again after rotating and stationary.   The abnormality detection device according to claim 2, wherein the abnormality detection unit repeats the additional abnormality detection process until it is determined that the abnormality is normal or abnormal. The synchronous motor is a motor that drives a hydraulic pump in an electro-hydraulic power steering apparatus that generates a steering assist force to be applied to a steering mechanism of a vehicle by hydraulic pressure,
The abnormality detection unit performs the additional abnormality detection process when it is determined that the synchronous motor is stationary when the vehicle is powered on, and the synchronous motor is powered on after the vehicle is powered on. The additional abnormality detection processing is not performed when it is determined that the synchronous motor is in the stationary state due to the motor control state transitioning from the rotational drive state to the stop state when the motor is in the undetermined state. The abnormality detection device according to claim 2 or 3. The second measuring unit includes
A direction determining unit that determines a direction of magnetic flux generated in the phase coil of the synchronous motor;
A current detection unit for detecting a drive current flowing through the synchronous motor;
When the phase coil is excited to direct the magnetic flux in a plurality of directions sequentially determined by the direction determination unit, according to the difference in the increase rate of the drive current at the start of excitation in each direction, An electrical angle identifying unit for identifying an electrical angle of the synchronous motor;
With
The said direction determination part determines the direction of the said magnetic flux so that the change of the direction of the said magnetic flux in two continuous excitations may become larger than 60 degree | times, The any one of Claims 1-4 characterized by the above-mentioned. Anomaly detection device. An output detector for detecting the output state of a plurality of hall sensors;
Based on the detection result of the output detection unit, a rotation state detection unit that detects the electrical angle of the rotor of the synchronous motor;
An output estimation unit that estimates the output state of the plurality of hall sensors from a measurement value different from the output of the hall sensor;
By comparing the output state of the plurality of hall sensors detected by the output detection unit with the output state of the plurality of hall sensors estimated by the output estimation unit when the synchronous motor is in a stationary state, An abnormality detection unit for detecting that there is an abnormality in the electrical angle detected by the rotation state detection unit;
A motor control unit for controlling the synchronous motor based on the electrical angle detected by the rotation state detection unit;
A motor control device comprising:

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