WO2019054091A1

WO2019054091A1 - Motor driving device, motor, electric power steering device, motor driving method and storage medium

Info

Publication number: WO2019054091A1
Application number: PCT/JP2018/029462
Authority: WO
Inventors: 知幸 ▲高▼田
Original assignee: 日本電産株式会社
Priority date: 2017-09-14
Filing date: 2018-08-06
Publication date: 2019-03-21
Also published as: JPWO2019054091A1

Abstract

[PROBLEM] To provide a motor driving device that excels in providing reliable detection values for the rotation angle of a motor. [SOLUTION] A motor driving device that drives a motor, said device comprising: three Hall elements that each output an analogue signal, the output value thereof periodically changing with respect to an electrical angle corresponding to the rotation angle of a rotor in the motor; a monitoring unit that monitors the analogue signals output from the three Hall elements and identifies any of the Hall elements outputting an analogue signal with an output value exceeding a limit value; and a calculation unit that uses the analogue signals output from the three Hall elements to calculate the rotation angle. If none of the three Hall elements have been identified by the monitoring unit, the calculation unit processes two analogue signals output from two of the three Hall elements and calculates the rotation angle. If one of the three Hall elements has been identified by the monitoring unit, the calculation unit processes the two analogue signals output from the remaining two Hall elements and calculates the rotation angle.

Description

Motor drive device, motor, electric power steering device, motor drive method, and recording medium

The present invention relates to a motor drive device, a motor, an electric power steering device, a motor drive method, and a recording medium.

A motor drive device for driving a motor used in an electric power steering device or the like detects a rotation angle of the motor using a plurality of Hall elements. The rotation angle detection device described in Patent Document 1 detects the rotation angle of a rotating body based on analog Hall signals output from a plurality of Hall elements.

Japanese Patent Application Laid-Open No. 2014-228413

The rotation angle detection device described in Patent Document 1 does not monitor whether any one of the plurality of Hall elements is moving normally. Therefore, there is a possibility that the rotation angle may be determined using the failed Hall element, which may be disadvantageous in terms of the reliability of the detection value.

An object of the present invention is, for example, to provide a motor drive device that is advantageous in terms of the reliability of the detected value of the rotation angle of the motor.

A motor drive according to an exemplary embodiment of the present application is a motor drive for driving a motor, and an analog signal whose output value periodically changes with respect to an electrical angle corresponding to a rotation angle of a motor rotor. From the three detection units, monitoring three Hall elements that output the signal, monitoring analog signals output from the three Hall elements, and specifying the Hall element that outputs the analog signal whose output value exceeds the limit value A calculation unit that calculates the rotation angle using the output analog signal, and the calculation unit calculates two of the three Hall elements when none of the three Hall elements is specified by the monitoring unit. The two analog signals output from the Hall element are processed to calculate the rotation angle, and when any one of the three Hall elements is specified by the monitoring unit, the remaining two holes are calculated. It processes the two analog signals outputted from the child calculates a rotation angle, characterized in that. A motor according to an exemplary embodiment of the present application includes the motor drive described above, a stator having a three-phase coil, and a rotor having a magnet. An electric power steering apparatus according to an exemplary embodiment of the present application includes a motor driven by the above-described motor drive apparatus.

A motor drive method according to an exemplary embodiment of the present application is a motor drive method for driving a motor, wherein an electrical angle corresponding to the rotation angle is output from three Hall elements that detect the rotation angle of a motor rotor. The step of acquiring three analog signals whose output value changes periodically with respect to each other, and monitoring whether the output value of any of the acquired three analog signals exceeds the limit value Calculate the total value of each of the output values of the first monitor process that specifies the Hall element that outputs the exceeding analog signal and the output value of the three analog signals for each electrical angle, and the calculated total value matches the fixed value Is monitored, and if the total value does not match the fixed value, electric angle candidates corresponding to each of the output values are determined, and the analog signal output from any two of the three Hall elements is obtained. Comprising a second monitoring step of specifying a Hall element which outputs the analog signal of the output value corresponding to the different second candidate from the first candidate corresponding to the force value, and wherein the. A recording medium according to an exemplary embodiment of the present application is a computer-readable recording medium storing a program that causes a computer to execute the above-described motor driving method for driving a motor.

According to an exemplary embodiment of the present application, a motor drive device, a motor drive method, and a recording medium storing a program that causes a computer to execute the motor drive method are advantageous in terms of the reliability of the detected value of the rotation angle of the motor. Can be provided. Further, since the reliability of the detection value of the rotation angle of the motor of the motor drive device is improved, the reliability of the motor and the electric power steering device can be improved.

FIG. 1 is a schematic view of an electric power steering apparatus provided with a motor drive device. FIG. 2 is a block diagram showing the configuration of the motor drive device. FIG. 3 is a flowchart showing a monitoring process of the Hall element by the monitoring unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention. Hereinafter, a motor drive device, a motor, an electric power steering device, a motor drive method, and a recording medium according to a first exemplary embodiment of the present application will be described.
<Electric Power Steering Device> FIG. 1 is a schematic view of an electric power steering device 1 provided with a motor drive device 30 according to the present embodiment. The electric power steering apparatus 1 is an apparatus for assisting a driver's steering wheel operation in transportation equipment such as a car. By providing the motor drive device 30 of the present embodiment, the stability of control of the electric power steering device 1 is improved.

As shown in FIG. 1, the electric power steering apparatus 1 of the present embodiment includes a steering angle detection unit 10, a motor 20, and a motor drive device 30. In the present embodiment, the motor 20 and the motor drive device 30 are built in a common housing. By making the motor 20 into a so-called mechanical-electrical integrated type, for example, the device can be miniaturized.

The steering angle detection unit 10 is attached to the steering shaft 92. The steering angle detection unit 10 detects the steering angle of the steering wheel 91. The detection result is output from the steering angle detection unit 10 to the motor drive device 30.

<Motor> In the present embodiment, a three-phase synchronous brushless motor is used as the motor 20. The motor 20 is composed of three-phase coils, and when the motor 20 is driven, current is supplied from the motor drive device 30 to each phase in the motor 20. When current is supplied, a rotating magnetic field is generated between a stator having a three-phase coil and a rotor having a magnet. As a result, the rotor rotates with respect to the stator of the motor 20.

<Motor Drive Device> The motor drive device 30 supplies a drive current to the motor 20 to drive the motor 20 using the electric power obtained from the external power supply 40. The driving force generated from the motor 20 is transmitted to the wheel 93 via the gearbox 50. Thereby, the steering angle of the wheel 93 is changed. Thus, the electric power steering apparatus 1 amplifies the torque of the steering shaft 92 by the motor 20 to change the steering angle of the wheel 93. Therefore, the driver can operate the steering wheel 91 with a light force.

FIG. 2 is a block diagram showing the configuration of the motor drive device 30. As shown in FIG. As shown in FIG. 2, the motor drive device 30 has a rotational position detection unit 31, a monitoring unit 32, a calculation unit 33, a control unit 34, an inverter drive unit 35, and an inverter circuit 36. The monitoring unit 32, the operation unit 33, and the control unit 34 include, for example, a computer having an operation processing unit such as a CPU, a memory such as a RAM, and a storage unit such as a hard disk drive. Instead of the computer, an electric circuit having an arithmetic device such as a microcontroller may be used.

<Rotational Position Detection Unit> The rotational position detection unit 31 is a Hall element provided coaxially with the rotation axis of the motor 20 or a Hall element for detecting the magnetic field of the sensor magnet. In particular, in the present embodiment, three

Hall elements

31A, 31B and 31C that output analog signals whose output value changes periodically with respect to an electrical angle corresponding to the rotation angle (also referred to as a mechanical angle) of the rotor of the motor 20 Use The

Hall elements

31A, 31B and 31C are arranged at intervals of 120 degrees along the rotation direction of the rotor. Also, the magnetic field of the two-pole sensor magnet is detected. Therefore, the mechanical angle of the rotor and the electrical angle of the Hall element coincide. The number and arrangement of Hall elements used and the number of poles of the magnet can be changed. Alternatively, a linear Hall IC may be used as a Hall element that outputs an analog signal.

<Monitoring Unit> The monitoring unit 32 monitors the analog signal output from the rotational position detecting unit 31, and specifies the rotational position detecting unit 31 that outputs an analog signal whose output value exceeds the limit value. In the present embodiment, the monitoring unit 32 monitors analog signals output from the

Hall elements

31A, 31B, and 31C, and specifies Hall elements that output analog signals whose output value exceeds the limit value.

<Calculation Unit> The calculation unit 33 uses the analog signal output from the rotational position detection unit 31 to calculate the rotation angle of the rotor. In this embodiment, the rotation angle of the rotor is calculated using the analog signals output from the

Hall elements

31A, 31B and 31C.

<Control Unit> The control unit 34 outputs a drive signal indicating the rotation amount of the rotor to the inverter drive unit 35 based on the rotation angle of the rotor calculated by the calculation unit 33, the detection result by the steering angle detection unit 10, and the like. The drive signal is, for example, a PWM drive signal of a pulse width modulation method (PWM method).

<Inverter Drive Unit> The inverter drive unit 35 is an electric circuit for operating the inverter circuit 36. The inverter drive unit 35 supplies the drive signal output from the control unit 34 to the inverter circuit 36.

<Inverter Circuit> The inverter circuit 36 is an electric circuit that supplies the current supplied from the external power supply 40 to each phase of the motor 20. The inverter circuit 36 has a switching element such as a field effect transistor. The inverter circuit 36 switches on / off of the current path flowing to each phase by the switching element based on the drive signal supplied from the inverter drive unit 35.

<Motor Driving Method> First, as a Hall element that outputs an analog signal whose output value exceeds the limit value, a motor driving method when none of the

Hall elements

31A, 31B, and 31C is specified by the monitoring unit 32 will be described. . In this case, the calculation unit 33 processes two analog signals output from any two of the three Hall elements to calculate the rotation angle, and the control unit 34 calculates the rotation angle of the rotor calculated by the calculation unit 33. To generate a drive signal that indicates the amount of rotation of the rotor.

Next, a motor drive method in the case where one of the

Hall elements

31A, 31B, and 31C is specified by the monitoring unit 32 as a Hall element that outputs an analog signal whose output value exceeds the limit value will be described. In this case, operation unit 33 processes the two analog signals output from the remaining two Hall elements to calculate the rotation angle, and control unit 34 uses the rotation angle of the rotor calculated by operation unit 33. , Generates a drive signal indicating an amount of rotation of the rotor.

As described above, according to the motor drive device 30 of the present embodiment, it is possible to identify the broken Hall element among the three Hall elements, so by processing the signals from the Hall elements other than the broken Hall element. The detection of the rotation angle of the motor can be continued. Therefore, it can be advantageous in terms of the reliability of the detected value of the rotation angle.

(Limit value) The limit value used by the monitoring unit 32 is the distance between the Hall element and the magnet that generates the magnetic field corresponding to the magnetic flux density detected by the Hall element, the size of the magnetic flux density, and the magnetic flux density and the output value of the Hall element It is determined based on at least one of the relationship with Since the limit value can be determined by the characteristics of the Hall element used, it can be advantageous in terms of the reliability of the detected value of the rotation angle.

(Calculation of Rotation Angle) A method of calculating the rotation angle of the rotor by the calculation unit 33 will be described. In the present embodiment, the computing unit 33 processes any two of analog signals output from the

Hall elements

31A, 31B, and 31C to calculate a rotation angle.

In the present embodiment, the calculation unit 33 performs processing to make the phase difference between two analog signals 90 degrees and processing to make the peaks of output values uniform. In the present embodiment, since the respective Hall elements are arranged at an interval of 120 degrees, the phase difference of the analog signal is also 120 degrees. By the processing of the arithmetic unit 33, a combination of analog signals having a phase difference of 90 degrees with each other is obtained.

Even when the phase difference between the two analog signals is not 90 degrees, the detection of the rotation angle of the motor can be continued by the processing of the calculation unit 33. Therefore, it is not necessary to increase the number of Hall elements used in the motor drive device in order to suppress the influence of the failure of the Hall elements on the detection accuracy of the rotation angle, which may be advantageous in cost, for example. In addition, the device mounting area can be reduced, which may be advantageous in terms of the device size.

Arithmetic unit 33 obtains a first corrected analog signal obtained by adding the other analog signal to one of two analog signals, and obtains a first corrected analog signal having a phase difference of 60 degrees with each other and one analog signal. Get a combination of

Arithmetic unit 33 obtains a second corrected analog signal obtained by adding the other analog signal to the first corrected analog signal, and obtains a combination of the second corrected analog signal and one analog signal having a phase difference of 90 degrees. obtain.

A process by the arithmetic unit 33 for obtaining a combination of analog signals having a phase difference of 90 degrees with each other will be specifically described. First, the analog signals output from the

Hall elements

31A, 31B and 31C are referred to as a first signal H _A , a second signal H _B and a third signal H _C , respectively. In this embodiment, a first signal _{H A} phase difference between the second signal _{H B} is 120 degrees. Other first signal _{H A} and the third signal _{H C,} the relationship of the phase difference of the second signal _{H B} and the third signal _{H C} is similar.

In the present embodiment, for example, a phase difference between the first correction analog signal and the first signal H _A plus a second signal H _B to the first signal H _A becomes 60 degrees. A second correction analog signal obtained by adding an additional second signal H _B to the first correction analog signal, the phase difference between the first signal H _A becomes 30 degrees. As a result, the phase difference between the second corrected analog signal and the second signal H _B is 90 degrees.

Depending on the arrangement of the Hall elements, it may not be necessary to obtain the second corrected analog signal. Further, instead of adding a second signal H _B to the first signal H _A, the second signal H _B by adding a first signal H _A, to obtain a first correction analog signal, first to the first correction analog signal Two signals H _B may be added to obtain a second corrected analog signal. In this case, the phase difference between the second corrected analog signal and the first signal _HA is 90 degrees. The relationship between the applied signal and the applied signal does not depend on the direction of rotation of the rotor.

As described above, even if the phase difference between the two analog signals is not 90 degrees by the processing of the calculation unit 33, the detection of the rotation angle of the motor can be continued. Therefore, it is not necessary to increase the number of Hall elements used in the motor drive device in order to suppress the influence of the failure of the Hall elements on the detection accuracy of the rotation angle, which may be advantageous in cost, for example. In addition, the device mounting area can be reduced, which may be advantageous in terms of the device size.

In addition, the calculation unit 33 may perform processing to align the peak values of the first corrected analog signal and one of the analog signals. In the present embodiment, the process of aligning the peaks is unnecessary. By aligning the peaks, detection of the rotation angle of the motor can be continued even if the amplitudes of the two analog signals are not aligned. Therefore, it is not necessary to increase the number of Hall elements used in the motor drive device in order to suppress the influence of the failure of the Hall elements on the detection accuracy of the rotation angle, which may be advantageous in cost, for example. In addition, the device mounting area can be reduced, which may be advantageous in terms of the device size.

The calculation unit 33 may align one of the peak values of the first corrected analog signal and one of the analog signals with the other peak value. This processing also allows the detection of the rotation angle of the motor to be continued even when the amplitudes of the two analog signals do not match. Therefore, it is not necessary to increase the number of Hall elements used in the motor drive device in order to suppress the influence of the failure of the Hall elements on the detection accuracy of the rotation angle, which may be advantageous in cost, for example. In addition, the device mounting area can be reduced, which may be advantageous in terms of the device size.

Note that, in the present embodiment, the computing unit 33 performs processing to make the peak values of the second corrected analog signal and one of the analog signals uniform. By this processing, even when the amplitudes of the two analog signals do not match, the detection of the rotation angle of the motor can be continued. Therefore, it is not necessary to increase the number of Hall elements used in the motor drive device in order to suppress the influence of the failure of the Hall elements on the detection accuracy of the rotation angle, which may be advantageous in cost, for example. In addition, the device mounting area can be reduced, which may be advantageous in terms of the device size.

In addition, the calculation unit 33 may align one of the peak values of the second corrected analog signal and one of the analog signals with the other peak value. This processing also allows the detection of the rotation angle of the motor to be continued even when the amplitudes of the two analog signals do not match. Therefore, it is not necessary to increase the number of Hall elements used in the motor drive device in order to suppress the influence of the failure of the Hall elements on the detection accuracy of the rotation angle, which may be advantageous in cost, for example. In addition, the device mounting area can be reduced, which may be advantageous in terms of the device size.

When none of the three Hall elements fail, the operation unit 33 uses the two analog signals output from any two Hall elements out of the three Hall elements as described above. The rotation angle is calculated by the process.

Therefore, the rotation angle of the motor can be detected by processing the signals from two of the three Hall elements. Therefore, it is not necessary to increase the number of Hall elements used in the motor drive device in order to suppress the influence on the detection accuracy of the rotation angle due to the failure of the Hall elements, which may be advantageous in cost, for example. In addition, the device mounting area can be reduced, which may be advantageous in terms of the device size.

In addition, even if the phase difference between the two analog signals is not 90 degrees and the amplitudes are not uniform, the rotation angle of the motor can be detected, thereby improving the workability of the arrangement of the Hall elements. sell.

According to the second exemplary embodiment of the present application, even if the output value of the analog signal output from the Hall element does not exceed the limit value, the Hall element may be broken. In the present embodiment, the monitoring unit 32 calculates the total value of the output values of the analog signals output from the three Hall elements for each electrical angle corresponding to the rotation angle of the rotor, and determines the calculated total value and the fixed value. And identify the faulty Hall element based on the comparison result.

The fixed value is the sum of the output values at each electrical angle when the three Hall elements are moving normally. The first signal H _A , the second signal H _B and the third signal H _C output from the

Hall elements

31A, 31 B and 31 _C , respectively, have a constant output value peak, so when operating normally, The sum of the output values is unchanged at any electrical angle.

The monitoring unit 32 specifies the failed Hall element as follows. First, in the case where the total value calculated for each electrical angle does not match the fixed value, the monitoring unit 32 measures the electric values corresponding to the output values of the first signal H _A , the second signal H _B and the third signal H _C. Ask for a corner candidate. Next, a Hall element for outputting an analog signal of an output value corresponding to a second candidate different from the first candidate corresponding to the output value of the analog signal output from any two of the three Hall elements Identify. The calculation unit 33 processes the analog signal of the output value corresponding to the first candidate to calculate the rotation angle.

That is, the monitoring unit 32 determines that the Hall element that outputs the analog signal corresponding to the first candidate is the Hall element operating normally, and breaks the Hall element that outputs the analog signal corresponding to the second candidate. It is determined that the Hall element has been For example, if the Hall element 31C is faulty, at least a portion of the candidates of the electrical angle corresponding to the output value of the first signal H _A and the second signal H _B (first candidate mentioned above) are overlapped . Then, the candidate of the electrical angle corresponding to the output value of the third signal H _C is a second candidate different from the first candidate. Calculating section 33 calculates the rotational angle by processing the analog signal of the first signal H _A and the second signal H _B.

As described above, even when the output value does not exceed the limit value, the failed Hall element can be identified. Therefore, the rotation angle of the motor can be obtained by processing the signals from the other Hall elements other than the failed Hall element. Detection can continue. Therefore, it can be advantageous in terms of the reliability of the detected value of the rotation angle.

(How to Determine Electrical Angle Candidate) The monitoring unit 32 may hold the correspondence between the output value and the electrical angle in advance, and determine the electrical angle candidate based on the correspondence. The correspondence relationship means, for example, a correspondence relationship in which the electrical angle corresponds to α degrees or β degrees, for the output value of x volts of the first signal _HA . One or two electrical angles correspond to one output value. When the correspondence relationship is used, it is not necessary to obtain candidates for the electrical angle by calculation, and for example, the calculation load of the monitoring unit 32 can be suppressed.

The monitoring unit 32 may calculate the candidate of the electrical angle by calculation from the output value of the analog signal. The case of calculating the candidate of the electrical angle from the output value of the first signal _HA will be described as an example. The output value of the first signal _HA is referred to as a first output value _{VA, and} the maximum output value of the first signal _HA is referred to as _VMA .

The candidate θ _A1 and the candidate θ _A2 are calculated by the equations (1) to (3) as A = V _A / V _MA .
θ _A1 = 180− (sin ⁻¹ A × 180 / π)) (1)
θ _A2 = sin ⁻¹ A × 180 / π, (A ≧ 0) (2)
θ _A2 = sin ⁻¹ A × 180 / π, (A <0) (3)

When the candidate of the electrical angle is calculated from the output value of the second signal H _B, the output value of the second signal H _B is taken as the second output value V _B , and the maximum output value of the second signal H _B is V _MB The candidate θ _B1 and the candidate θ _B2 are calculated by Equations (4) to (6), where B = V _B / V _MB .
θ _B1 = 120 + (sin ⁻¹ B × 180 / π)) (4)
θ _B2 = −60−sin ⁻¹ B × 180 / π, ( ⁻¹ ≦ B ≦ −0.866) (5)
θ _B2 = 300−sin ⁻¹ B × 180 / π, (−0.866 ≦ B ≦ 1) (6)

When calculating the candidate of the electrical angle from the output value of the third signal H _C, the output value of the third signal H _C is taken as the third output value V _C , and the maximum output value of the third signal H _C is V _MC , C The candidate θ _C1 and the candidate θ _C2 are calculated by the equations (7) to (9) as = V _C / V _MC .
θ _C1 = 240 + (sin ⁻¹ C × 180 / π)) (7)
θ _C2 = 60−sin ⁻¹ C × 180 / π, ( ⁻¹ ≦ B ≦ −0.866) (8)
θ _C2 = 270 + sin ⁻¹ C × 180 / π, (−0.866 ≦ B ≦ 1) (9)

As described above, there is an advantage that it is not necessary to create a table indicating the correspondence between the output value and the electrical angle, for example, by obtaining the electrical angle candidate by calculation.

When the fixed value and the total value match, the computing unit 33 calculates the rotation angle using two analog signals output from any two Hall elements of the three Hall elements.

The monitoring unit 32 may also use the detection result of the steering angle detection unit 10 to specify the failed Hall element. That is, first, the monitoring unit 32 calculates the rotation angle by the operation unit 33 for each of the three types of combinations obtained by selecting two Hall elements from the three Hall elements. The monitoring unit 32 compares the calculation result with the detection result of the steering angle detection unit 10, and specifies a combination corresponding to the rotation angle closest to the detection result among the three types of combinations. The monitoring unit 32 specifies the Hall element included in both of the remaining combinations as the failed Hall element.

According to this method, the faulty Hall element is identified based on the detection result of the steering angle detection unit without calculating the table showing the correspondence between the output value of the Hall element and the electrical angle or the candidate of the electrical angle. be able to.

The monitoring of the Hall element by the method of the first embodiment and the monitoring of the Hall element by the method of the second embodiment may be performed alone or in combination. When used in combination, the order is random.

In any case, since it is possible to identify the failed Hall element among the three Hall elements, the detection of the rotation angle of the motor can be continued by processing the signals from the Hall elements other than the failed Hall element. it can. Therefore, it can be advantageous in terms of the reliability of the detected value of the rotation angle.

In the monitoring according to the second embodiment, even if the total value matches the fixed value, it is possible that one of the output values may exceed the limit value used in the monitoring according to the first embodiment. Even in this case, it is possible to specify the failed Hall element by using the monitoring according to the second embodiment and the monitoring according to the first embodiment in combination. Therefore, by processing the signals from the Hall elements other than the failed Hall element, the detection of the rotation angle of the motor can be continued. Therefore, it can be advantageous in terms of the reliability of the detected value of the rotation angle.

<Flowchart> FIG. 3 is a flowchart of a monitoring process of a Hall element by the monitoring unit 32 according to the first embodiment and the second embodiment. The case of performing monitoring (referred to as a second monitoring step) according to the method of the second embodiment next to monitoring (referred to as a first monitoring step) according to the method of the first embodiment will be described.

First, in step S30, the monitoring unit 32 acquires three analog signals. Next, in step S31, the monitoring unit 32 monitors whether or not the output value of any of the three analog signals exceeds the limit value. If the limit value is exceeded, a Hall element that outputs an analog signal exceeding the limit value is specified in step S32. Step S31 and step S32 are the first monitoring step.

If the limit value is not exceeded, the monitoring unit 32 calculates the total value of the output values of the three analog signals for each electrical angle in step S33, and the calculated total value matches the fixed value. Monitor if it is

If they do not match, in step S34, the monitoring unit 32 determines the candidate of the electrical angle corresponding to each of the output values, and outputs the analog signal output from any two of the three Hall elements. Find the first candidate corresponding to the value. Also, the monitoring unit 32 specifies a Hall element that outputs an analog signal of an output value corresponding to a second candidate different from the first candidate. Step S33 and step S34 are the second monitoring step.

When the fixed value and the total value match, in step S35, the calculation unit 33 calculates a rotation angle using any two analog signals of the three analog signals. The order of the first monitoring step and the second monitoring step may be switched. Moreover, you may perform in parallel.

A program that causes a computer to execute the above driving method may be stored in a computer readable recording medium such as a semiconductor memory, and the computer may execute the program to realize the driving method including the above monitoring method.

According to the above monitoring method, it is possible to identify the broken Hall element among the three Hall elements, so that the detection of the rotation angle of the motor is continued by processing the signals from the Hall elements other than the broken Hall element. Can. Therefore, it can be advantageous in terms of the reliability of the detected value of the rotation angle.

The motor 20 is not limited to three phases. Also, the motor drive device 30 described above may be applied to devices other than the power steering device. For example, the motor drive device 30 described above may drive a motor used in another part of a transportation device such as a car. In addition, a motor mounted on an apparatus other than an automobile such as an industrial robot may be driven by the motor drive device 30 described above.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the present invention.

Claims

A motor drive unit for driving the motor, wherein
Three Hall elements that output analog signals whose output value changes periodically with respect to an electrical angle corresponding to the rotation angle of the motor rotor;
A monitoring unit that monitors the analog signals output from the three Hall elements and identifies the Hall elements that output the analog signals whose output value exceeds a limit value;
And a calculation unit that calculates the rotation angle using the analog signal output from the three Hall elements,
The arithmetic unit is
If none of the three Hall elements is specified by the monitoring unit, two rotations of the two analog signals output from the two Hall elements of the three Hall elements are processed to calculate the rotation angle. ,
When any one of the three Hall elements is specified by the monitoring unit, the two analog signals output from the remaining two Hall elements are processed to calculate the rotation angle. Motor drive device.
The limit value is at least one of a distance between the Hall element and a magnet generating a magnetic field corresponding to a magnetic flux density detected by the Hall element, a magnitude of the magnetic flux density, and a relationship between the magnetic flux density and the output value. The motor drive device according to claim 1, wherein the motor drive device is determined based on either of them.
The monitoring unit calculates the sum value of the output values of the analog signals output from the three Hall elements for each electrical angle when none of the three Hall elements is specified by the monitoring unit. The calculated total value is compared with a fixed value, and when the total value does not match the fixed value, candidates for the electrical angle corresponding to each of the output values are obtained, and the three holes are calculated. The Hall element that outputs the analog signal of the output value corresponding to a second candidate different from the first candidate corresponding to the output value of the analog signal output from any two of the elements is specified And
The motor drive device according to claim 1, wherein the arithmetic unit processes the analog signal of the output value corresponding to the first candidate to calculate the rotation angle.
The motor drive device according to claim 3, wherein the monitoring unit holds in advance a correspondence between the output value and the electrical angle, and determines the candidate based on the correspondence.
The motor drive device according to claim 3, wherein the monitoring unit calculates the candidate using a ratio of the output value and a maximum output value of the analog signal having the output value.
A motor drive unit for driving the motor, wherein
Three Hall elements that output analog signals whose output value changes periodically with respect to an electrical angle corresponding to the rotation angle of the motor rotor;
A monitoring unit that monitors the analog signal output from the three Hall elements;
And a calculation unit that calculates the rotation angle using the analog signal output from the three Hall elements,
The monitoring unit calculates a total value of the output values of the analog signals output from the three Hall elements for each electrical angle, compares the calculated total value with a fixed value, and calculates the total value. If the value does not match the fixed value, candidates for the electrical angle corresponding to each of the output values are determined, and the output value of the analog signal output from any two of the three Hall elements is obtained as the output value. Identifying the Hall element that outputs the analog signal of the output value corresponding to a second candidate different from the corresponding first candidate;
The arithmetic unit is
If the total value matches the fixed value, two rotations of the analog signal output from two of the three Hall elements are processed to calculate the rotation angle;
A motor drive device characterized by processing said analog signal of said output value corresponding to said 1st candidate, and calculating said rotation angle, when said total value does not correspond with said fixed value.
The motor drive device according to claim 6, wherein the monitoring unit has a correspondence between the output value and the electrical angle in advance, and determines the candidate based on the correspondence.
The motor drive device according to claim 6, wherein the monitoring unit calculates the candidate using a ratio of the output value to a maximum output value of the analog signal having the output value.
The monitoring unit identifies the Hall element that outputs the analog signal whose output value exceeds a limit value when the total value matches the fixed value,
The arithmetic unit processes the two analog signals output from the remaining two Hall elements to calculate the rotation angle when any one of the three Hall elements is specified by the monitoring unit. The motor drive device according to any one of claims 6 to 8, wherein:
A motor comprising: the motor drive device according to any one of claims 1 to 9; a stator having a three-phase coil; and a rotor having a magnet.
An electric power steering apparatus comprising a motor driven by the motor drive apparatus according to any one of claims 1 to 9.
It has a steering angle detection unit that detects the steering angle of the steering,
The monitoring unit
The total value of the output values of the analog signals output from the three Hall elements is calculated for each electrical angle, the calculated total value is compared with a fixed value, and the total value is the fixed value. If it does not match
The rotation angle calculated by the calculation unit is compared with the detection result of the steering angle detection unit for each of the three types of combinations obtained by selecting two of the Hall elements from the three hall elements, and The electric motor according to claim 11, wherein a combination corresponding to the rotation angle closest to the detection result among the kinds of combinations is specified, and the Hall elements included in both of the remaining combinations are specified. Power steering device.
A motor driving method for driving a motor,
Obtaining three analog signals output from three Hall elements for detecting a rotation angle of a motor rotor and having an output value periodically changing with respect to an electrical angle corresponding to the rotation angle;
A first monitoring step of monitoring whether or not the output value of any of the acquired three analog signals exceeds a limit value, and identifying the Hall element that outputs the analog signal exceeding the limit value; ,
A total value of each of the output values of the three analog signals is calculated for each electrical angle, and it is monitored whether the calculated total value matches a fixed value, and the total value is determined as the fixed value. If they do not match, a candidate for the electrical angle corresponding to each of the output values is determined, and a first candidate corresponding to the output value of the analog signal output from any two of the three Hall elements And D. a second monitoring step of identifying the Hall element that outputs the analog signal of the output value corresponding to a second candidate different from the second candidate.
A computer readable recording medium storing a program for causing a computer to execute a motor driving method for driving a motor, the computer readable recording medium comprising:
The motor drive method is
Acquiring three analog signals that are output from three Hall elements and whose output value changes periodically with respect to an electrical angle corresponding to the rotation angle;
A first monitoring step of monitoring whether or not the output value of any of the acquired three analog signals exceeds a limit value, and identifying the Hall element that outputs the analog signal exceeding the limit value; ,
A total value of each of the output values of the three analog signals is calculated for each electrical angle, and it is monitored whether the calculated total value matches a fixed value, and the total value is determined as the fixed value. If they do not match, a candidate for the electrical angle corresponding to each of the output values is determined, and a first candidate corresponding to the output value of the analog signal output from any two of the three Hall elements A second monitoring step of identifying the Hall element that outputs the analog signal of the output value corresponding to a second candidate different from the second candidate.