JP2013257165A - Rotational angle detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a rotational angle having a desired level of reliability to be obtained even if any one or two of A, B and Z phase signals become abnormal.SOLUTION: A decoder 1 detects (and decodes) a rotational angle φ of a motor 1 on the basis of A, B and Z phase signals matching the rotation of the motor 1. An angle signal monitoring unit 43 determines abnormality, if any, of one or two of the A, B and Z phase signals. The decoder 1, when all the A, B and Z phase signals are normal, detects the rotational angle φ by a predetermined normal decoding system based on the A, B and Z phase signals. Or if the angle signal monitoring unit 43 determines any one or two of the A, B and Z phase signals to be abnormal, the decoder 1 detects the rotational angle φ by a prescribed abnormal decoding system using one or two other normal phase signals which are not determined to be abnormal.

Description

  The present invention relates to a rotation angle detection device that detects a rotation angle of a rotating body.

  In a motor serving as a drive source of an electric vehicle, a rotation angle (electrical angle of a rotor) that is position information of the motor is important information for coordinate conversion in vector control, for example. A resolver is known as a sensor for detecting the rotation angle (see, for example, Patent Document 1).

  In general, angle information output from a resolver is converted into digital angle data by an RDC (Resolver to Digital Converter). The angle data may be used for various controls as it is, but is often converted into A, B, and Z phase signals by an encoder and output to various circuits such as a microcomputer. The A, B, and Z phase signals converted by the encoder have the same properties as the A, B, and Z phase signals output by a known incremental rotary encoder. Also, many RDCs have an encoder built therein so that the RDC itself outputs A, B, and Z phase signals.

  Conventionally, various controls such as an encoder or RDC (hereinafter referred to as an encoder or the like) that outputs A, B, and Z phase signals and a microcomputer that performs various controls by converting these A, B, and Z phase signals into rotation angles. In general, the circuits are arranged close to each other. Therefore, the loss of the A, B, and Z phase signals from the encoder and the like to various control circuits has not been considered much.

JP 2011-95094 A

  However, in recent years, from the viewpoint of functional safety, it has become necessary to use A, B, Z phase signals indicating the rotation angle of a motor in a plurality of control circuits (a plurality of microcomputers, etc.). For example, in addition to the control microcomputer that controls the motor, there is a demand for mounting a monitoring microcomputer for monitoring the operation of the control microcomputer, and the monitoring microcomputer also requires information on the rotation angle of the motor.

  In order to cope with this, it is necessary to transmit the A, B, Z phase signals from the encoder or the like to the plurality of control circuits. Therefore, it is difficult to arrange the encoder and the like and the plurality of control circuits close to each other.

  If the encoder or the like is away from the control circuit, any of the A, B, and Z phase signals transmitted between them may not be transmitted normally due to some factor such as disconnection or sticking. When such a transmission abnormality occurs, a normal rotation angle cannot be obtained on the control circuit side that performs various controls by converting the A, B, and Z phase signals into rotation angles. There is a risk that it will not be possible.

  The present invention has been made in view of the above problems, and even if any one or two of the A, B, and Z phase signals become abnormal, desired reliability can be obtained from these A, B, and Z phase signals. It is an object to obtain a rotation angle having.

The rotation angle detection device of the present invention made to solve the above problems includes rotation angle detection means and pulse signal determination means.
The rotation angle detection means inputs the first and second pulse signals that are out of phase with each other, and 360 degrees / n (n larger than the certain angle), each time the rotating body rotates by a certain angle. Is an integer greater than or equal to 1) The rotation angle of the rotating body is detected while detecting the direction of rotation of the rotating body by a predetermined normal detection method using a third pulse signal input every time it rotates.

The pulse signal determining means determines whether or not at least one of the pulse signals is abnormal.
Then, the rotation angle detecting means, when any one or two of the respective pulse signals is determined to be abnormal by the pulse signal determining means, is another one or two normal pulse signals that are not determined to be abnormal. The rotation angle of the rotating body is detected by a predetermined abnormality detection method according to the type of the normal pulse signal.

  If any one or two of the pulse signals are normal, the accuracy may be inferior to the case where all the pulse signals are normal. The rotation angle which has the property can be obtained. Therefore, in the present invention, an abnormality detection method is individually prepared according to which one of the pulse signals is normal, and when an abnormality occurs, another normal pulse signal is used, The rotation angle is detected by an abnormality detection method corresponding to a normal pulse signal.

  Therefore, according to the rotation angle detection device of the present invention, even if any one or two of each pulse signal becomes abnormal, it has a desired reliability from each pulse signal (specifically, from a normal pulse signal). A rotation angle can be obtained.

  In addition, the code | symbol in the parenthesis described in the claim is an example which shows a corresponding relationship with the specific means etc. which are described in embodiment mentioned later, Comprising: The technical scope of this invention is not limited.

It is a block diagram showing the control system of the electric vehicle of embodiment. It is explanatory drawing which illustrates A, B, Z each phase signal input into the monitoring microcomputer, and the rotation angle (phi) decoded based on these, (a) is an example at the time of A, B, Z phase signal normal (B) is an example when the Z phase is abnormal, and (c) is an example when the AB phase is abnormal. It is explanatory drawing which illustrates transition of the counter value of each counter when B phase abnormality generate | occur | produces, and rotation angle (phi) output based on these. It is a flowchart which represents typically operation | movement of the angle signal monitoring part in the monitoring microcomputer. It is a flowchart which represents typically the operation | movement of the decoder in a monitoring microcomputer. It is a flowchart showing the monitoring control process which the control microcomputer monitoring part (CPU) in a monitoring microcomputer performs. It is explanatory drawing showing the phase relationship between a motor current and rotation angle (phi).

Preferred embodiments of the present invention will be described below with reference to the drawings.
In the present embodiment, an example in which the present invention is applied to an electric vehicle will be described. As shown in FIG. 1, the electric vehicle of the present embodiment includes a travel motor (hereinafter simply referred to as “motor”) 1, a battery 3, an inverter 5, and a travel motor control ECU (hereinafter referred to as “MGECU”). 7 and an integrated control ECU (hereinafter referred to as “EVECU”) 9 are mounted.

  The motor 1 is a known AC synchronous motor. The output shaft 1 a of the motor 1 is connected to the left and right drive wheels 11 via a differential gear 10. The battery 3 is a well-known secondary battery (for example, a nickel metal hydride secondary battery) that can be charged and discharged, and supplies a predetermined DC voltage (for example, 288 V) necessary for driving the motor 1 to the motor 1 via the inverter 5. .

  The inverter 5 converts the DC voltage of the battery 3 into a three-phase AC, and drives the motor 1 by the converted U-phase, V-phase, and W-phase three-phase AC currents. Specifically, the inverter 5 of the present embodiment includes six switching elements made of, for example, an IGBT (insulated gate bipolar transistor) and a drive circuit that drives the switching elements. The drive circuit converts the direct current of the battery 3 into a three-phase alternating current by turning on / off the switching element based on the pulse width modulation signals UU, UV, UW input from the MGECU 7.

  The MGECU 7 controls the motor 1 via the inverter 5. The EV ECU 9 is an ECU that controls the entire control of the electric vehicle. The EVECU 9 generates various commands, signals, and the like necessary for the MGECU 7 to control the motor 1 and outputs them to the MGECU 7.

  The output shaft 1a of the motor 1 is provided with a resolver 13 as a sensor for detecting the rotation angle of the motor 1 (specifically, the rotation angle of the rotor of the motor 1). It should be noted that the rotation angle (or rotation angle) in this embodiment means an electrical angle (so-called electrical angle), not a mechanical rotation angle of the motor 1 unless otherwise specified.

  As is well known, the resolver 13 outputs two rotation detection signals Sa and Sb whose amplitude changes sinusoidally according to the rotation angle θ of the motor 1 and whose phase is shifted by 90 ° in electrical angle. That is, in the resolver 13, the excitation signal f (t) (= sin ωt) having a constant frequency is supplied to the primary coil of the resolver, so that the rotation detection signal corresponding to the rotation angle θ of the motor 1 is output from each of the secondary coils. The rotation detection signal Sa (= f (t) · sin θ) having a waveform obtained by amplitude-modulating the excitation signal f (t) with sin θ, and the rotation detection signal Sb having a waveform obtained by amplitude-modulating the excitation signal f (t) with cos θ. = F (t) · cos θ) is output.

  Note that θ is an angle obtained by multiplying the actual mechanical rotation angle of the motor 1 by n times (n is an integer of 1 or more), and also represents the electrical angle of the resolver 13 (the electrical angle of the motor 1). Further, n is the number of rotations of θ per rotation of the motor 1 (that is, a double speed ratio of the electrical angle with respect to the mechanical angle), and is generally called a shaft double angle. As an example, the resolver 13 of the present embodiment has an axial multiple angle n = 1.

  Current sensors 25, 26, and 27 for each phase are disposed in each of the current supply lines 21, 22, and 23 for each phase from the inverter 5 to the motor 1. The U-phase current sensor 25 detects the U-phase current level of the motor 1 and outputs a U-phase current signal corresponding thereto. Similarly, the V-phase current sensor 26 detects the V-phase current level of the motor 1 and outputs a V-phase current signal corresponding thereto, and the W-phase current sensor 27 detects the W-phase current level of the motor 1. A W-phase current signal corresponding to this is output. And the current signal of each phase from each current sensor 25-27 is input into MGECU7. The upper waveform in FIG. 7 shows a waveform example of each phase current.

  The EV ECU 9 includes a signal indicating an accelerator opening input from an accelerator sensor (not shown), a signal indicating a shift position input from a shift switch (not shown), and a vehicle speed (vehicle) input from a vehicle speed sensor (not shown). Various controls in the electric vehicle are performed based on various signals indicating the vehicle state, such as a signal indicating the speed. One of the controls is generation of a torque command.

  That is, the EV ECU 9 determines a necessary driving torque that the motor 1 should output based on the various signals described above using, for example, a torque map. Then, a torque command indicating the drive torque is output to MGECU 7. In addition to the torque command, the EV ECU 9 also outputs a signal (vehicle speed signal) indicating the vehicle speed to the MGECU 7.

  The MGECU 7 mainly includes a control microcomputer 30 that controls the motor 1 via the inverter 5, a monitoring microcomputer 40 that monitors the operation of the control microcomputer 30, and a pulse width modulation circuit (PWM circuit) 36. .

  The control microcomputer 30 includes a resolver / digital converter (RDC) 31, a motor control unit 32, and an encoder 33. Of these, the motor control unit 32 is actually a CPU, and functions as the motor control unit 32 when the CPU executes various programs. In addition, although illustration is omitted, the control microcomputer 30 includes well-known constituent elements that are generally provided in a general microcomputer, such as a ROM, a RAM (SRAM), and an I / O.

  The RDC 31 is well-known hardware that converts the rotation detection signals Sa and Sb from the resolver 13 into angle data (rotation angle θ). That is, the RDC 31 supplies an excitation signal f (t) to the resolver 13 and inputs rotation detection signals Sa and Sb output from the resolver 13, and rotates the motor 1 from the rotation detection signals Sa and Sb. Digital data (angle of rotation θ) indicating the angle is output. The RDC 31 in this embodiment is a digital tracking type RDC. Since the angle data conversion method by the RDC of the digital tracking method is well known, detailed description is omitted here.

  The motor control unit 32 inputs the rotation angle θ from the RDC 31 as a detected value of the rotation angle of the motor 1 and, for example, the rotation number (rotation speed) of the motor 1 from the change per unit time of the rotation angle θ. Is calculated.

  Then, the motor control unit 32 controls the PWM circuit 36 based on the rotation angle θ and the number of rotations which are the rotation information of the motor 1, the respective phase current signals from the current sensors 25 to 27, the torque command value from the EV ECU 9, and the like. By driving the inverter 5 via the motor 1, a desired torque corresponding to the driving state of the vehicle is generated in the motor 1. Although the control of the motor 1 is known, it will be briefly described.

  That is, the motor control unit 32 outputs, to the pulse width modulation circuit 36, a control signal for causing the motor 1 to generate the torque indicated by the torque command value based on the torque command value input from the EV ECU 9. At this time, the motor control unit 32 determines each of the three phases flowing through the motor 1 based on at least two of the current signals from the current sensors 25 to 27 (for example, a U-phase current signal and a W-phase current signal). Control signals to the pulse width modulation circuit 36 (and thus pulse width modulation signals UU, UV, UW from the pulse width modulation circuit 36 to the inverter 5) are set so that the current becomes a target value corresponding to the torque command value. Feedback control.

  More specifically, the calculation in this feedback control is performed in the dq axis rotating coordinate system. That is, while calculating the current command value of each of the d and q axes in accordance with the input torque command value, each phase current signal from each of the current sensors 25 to 27 is converted into an actual current value of two phases (d and q axes). Convert coordinates to. Then, a control signal to the pulse width modulation circuit 36 is generated by feedback control based on the current command value after the coordinate conversion and the actual current value. At the time of the coordinate conversion described above, and further at the time of generating a control signal by feedback control, the rotation angle θ and the rotation speed of the motor 1 are required.

  The encoder 33 converts (encodes) the rotation angle θ (digital value) generated by the RDC 31 into three angle signals of an A phase signal, a B phase signal, and a Z phase signal. These phase signals are the same as the A, B, and Z phase signals output by a known incremental encoder.

  That is, as shown in FIG. 2A, the A-phase signal is a pulse signal that generates a pulse having a predetermined pulse width every time the motor 1 is electrically rotated by a certain angle. Similarly to the A phase signal, the B phase signal is a pulse signal that generates a pulse having a predetermined pulse width every time the motor is electrically rotated by a certain angle. However, the A phase signal and the B phase signal are out of phase with each other, and in this embodiment, there is a phase difference of 90 degrees. The Z-phase signal is a pulse signal that generates a pulse having a predetermined pulse width every time the motor 1 makes one electrical rotation.

  The A, B, and Z phase signals encoded by the encoder 33 are transmitted to the monitoring microcomputer 40. That is, in the present embodiment, the monitoring microcomputer 40 also needs information regarding the rotation angle of the motor 1. As a specific method for transmitting the rotation information of the motor 1, it is conceivable that the rotation angle θ generated by the RDC 31 is directly transmitted in parallel or serial. However, a large number of transmission lines are required for parallel transmission. In the present embodiment, since the angular resolution is 12 bits, twelve transmission lines are required for parallel transmission, which is not realistic. On the other hand, when serial transmission is performed, the transmission time becomes long, which is also not realistic. Therefore, the rotation angle θ generated by the RDC in the control microcomputer 30 is encoded into A, B, and Z phase signals and transmitted to the monitoring microcomputer 40.

  The pulse width modulation circuit 36 generates a pulse width modulation signal UU, UV, UW corresponding to each phase of the three-phase alternating current according to a control signal from the control microcomputer 30, and each of the pulse width modulation signals UU, UV, UW. Is output to the inverter 5. As a result, a U-phase, V-phase, and W-phase three-phase alternating current is supplied from the inverter 5 to the motor 1.

  The monitoring microcomputer 40 includes a decoder 41, a control microcomputer monitoring unit 42, an angle signal monitoring unit 43, and an estimation counter 44. Of these, the control microcomputer monitoring unit 42 is actually a CPU, and functions as the control microcomputer monitoring unit 42 when the CPU executes various programs. In addition, although illustration is omitted, the monitoring microcomputer 40 includes well-known components that are generally provided in general microcomputers, such as ROM, RAM (SRAM), and I / O.

  The decoder 41 converts (decodes) the angle signal (A, B, Z phase signals) transmitted from the control microcomputer 30 into digital angle data (rotation angle) φ. The specific decoding method by the decoder 41 differs depending on the states of the A, B, and Z phase signals. That is, in this embodiment, the angle signal monitoring unit 43 monitors whether the A, B, and Z phase signals are normal, and if any one or two becomes abnormal, this is indicated. Diagnostic information (angle signal diagnostic) is output. The decoder 41 switches the decoding method according to the presence / absence of the angle signal diagnosis from the angle signal monitoring unit 43 and the type of the angle signal diagnosis.

  When the angle signal diagnosis is not output from the angle signal monitoring unit 43, that is, when the A, B, and Z phase signals are normal, the decoder 41 performs decoding by the normal decoding method Do. Specifically, the rotational direction of the motor 1 is determined based on the phase difference between the A phase signal and the B phase signal. In the present embodiment, when the edge of the A phase signal rises after the edge of the B phase signal rises, when the edge of the B phase signal falls after the edge of the A phase signal rises, the edge of the B phase signal becomes When the edge of the A phase signal falls after falling, and when the edge of the B phase signal rises after the falling edge of the A phase signal, the motor 1 rotates in the forward direction (forward rotation). It shall be. When the edge change is opposite to the above (for example, when the B-phase signal falls after the A-phase signal falls), the motor 1 is assumed to rotate in the reverse direction (reverse rotation).

  The built-in edge counter is incremented or decremented each time the edge rise and fall of the A-phase signal and the B-phase signal occur while discriminating the rotation direction of the motor 1 in this way. In the present embodiment, the edge counter is counted up while the motor 1 is rotating forward, and the edge counter is counted down while the motor 1 is rotating backward.

The Z-phase signal is a signal indicating the reference of the rotational position, and the counter value of the edge counter is reset to 0 each time the edge of the Z-phase signal rises.
Then, the counter value of the edge counter counted up or down in this way is output to the control microcomputer monitoring unit 42 as a decoding result (rotation angle φ) by the normal decoding method Do. Note that the counter value “0” of the edge counter that is reset by the rising edge of the Z-phase signal corresponds to the initial value of the present invention, and the A and B phase signals (one of which is abnormal) In this case, the counter value counted up or counted up by the other signal) corresponds to the relative angle change amount of the present invention.

In the present embodiment, the angular resolution M [bit] is 12 bits. That is, when the counter value of the edge counter is reset to 0 by the Z-phase signal and then counted up to 4095 (= 2 ^M -1 = 2 ¹² -1), the counter value is reset to 0 again by the Z-phase signal. Is done. In this embodiment, since the edge counter itself is a 12-bit counter that can count up from 0 to 4095, even if no edge change of the Z-phase signal occurs, the counter value becomes 0 after 4095. Note that the angular resolution of 12 bits is merely an example, and how to set the resolution and how to count up and down based on the A and B phase signals can be appropriately determined. it can.

  FIG. 2A shows an example of each phase signal when the motor 1 is rotating forward and all the A, B, and Z phase signals are normal. As described above, when each phase signal is normal, the decoder 41 performs decoding by the above-described normal decoding method Do. That is, the counter value of the edge counter is incremented every time the edge change of the A and B phase signals occurs, and the counter value is reset to 0 when the rising edge of the Z phase signal occurs. Then, the counter value of the edge counter is output as the final decoded output (rotation angle φ).

  On the other hand, when one or two of the A, B, and Z phase signals become abnormal and the angle signal diagnosis is output from the angle signal monitoring unit 43, the decoder 41 responds to the angle signal diagnosis. Decoding is performed by switching to a predetermined abnormality decoding system (that is, depending on which of the A, B, and Z phase signals is abnormal). That is, decoding is performed using a normal signal among the A, B, and Z phase signals. Details of the various angle signal diagnostics and the abnormality decoding method will be described later.

  The control microcomputer monitoring unit 42 monitors whether the control microcomputer 30 is operating normally, that is, whether the feedback control by the motor control unit 32 is normally performed. Specifically, the actual output torque of the motor 1 is calculated based on the rotation angle φ generated (decoded) by the decoder 41 and the phase current signals from the current sensors 25 to 27, and the torque from the EV ECU 9 is calculated. Compare with the command value. Based on the comparison result, the state of the control microcomputer 30 is determined. For example, if the calculated output torque substantially matches the torque command value, it is determined that the control microcomputer 30 is operating normally, and if the difference between the calculated output torque and the torque command value is large, the control microcomputer 30 is abnormal. It is judged that.

  The specific method of calculating the output torque by the control microcomputer monitoring unit 42 and comparing it with the torque command value is basically the same as the feedback control by the motor control unit 32 of the control microcomputer 30, and is based on the dq axis rotation coordinate system. Done.

  When the control microcomputer monitoring unit 42 determines that the control microcomputer 30 is abnormal, the control microcomputer monitoring unit 42 stores the control microcomputer abnormality diagnosis, which is diagnosis information indicating the fact, in its own RAM (SRAM) and outputs it to the EV ECU 9.

  When receiving the control microcomputer abnormality diagnosis from the monitoring microcomputer 40, the EV ECU 9 stops the drive of the motor 1 by setting the torque command value to 0 (or the vicinity thereof), for example, and an abnormality is detected for the vehicle driver. Predetermined control microcomputer abnormality handling processing, such as notifying a warning to the effect that it has occurred, is executed. Note that the specific contents of the control microcomputer abnormality handling process can be determined as appropriate.

  Further, an angle signal diagnosis from the angle signal monitoring unit 43 is also input to the control microcomputer monitoring unit 42. Therefore, when an angle signal diagnosis is input from the angle signal monitoring unit 43 due to an abnormality in the A, B, Z phase signals, the angle signal diagnosis is stored in its own SRAM and output to the EV ECU 9.

  When the EV ECU 9 receives the angle signal diagnosis from the monitoring microcomputer 40, the EV ECU 9 executes a predetermined angle signal abnormality handling process such as prompting the driver to evacuate to stop the vehicle early. In other words, the motor drive is not forcibly stopped immediately, and the minimum retreat travel is allowed. It should be noted that the specific content of the angle signal abnormality handling process can also be determined as appropriate.

  The estimation counter 44 estimates (counts) the rotation angle based on the Z-phase signal. Specifically, each time a Z-phase signal pulse (hereinafter also referred to as a “Z-phase pulse”) is generated (for example, every edge rising timing), 1 Z Estimate the time required to rotate by an angle of bits. For example, when a Z-phase pulse is generated, TA is the previous period that is the period from the timing at which the previous Z-phase pulse was generated (previous timing) to the timing at which the current Z-phase pulse was generated, and a Z-phase pulse was generated immediately before the previous timing. When the previous cycle that is the period from the timing (previous timing) to the previous timing is TB, the next cycle TZ that is the period until the next Z-phase pulse is generated is calculated by the following equation (1).

TZ = 2 · TA-TB (1)
Then, using the estimated next period TZ, an estimated count period Tx that is a time required to rotate by an angle of 1 bit is estimated by the following equation (2).

Tx = TZ / 2 ^M (2)
Since the angular resolution of the present embodiment is 12 bits, in the present embodiment, the calculation of the above equation (2) is obtained by dividing the next period TZ by 4096 to obtain the estimated count period Tx. The reciprocal of this estimated count period Tx corresponds to the rotational speed of the present invention.

  Each time the Z-phase pulse is generated, the estimation counter 44 estimates and calculates the estimated count period Tx based on the two most recent periods as described above, and each time the estimated count period Tx elapses, the estimated value is changed from 0 to 1. Count up one by one (or count down from 4095 one by one). Then, when the Z-phase pulse is generated again, the estimated count period Tx is newly calculated again based on the latest two periods, and counted up again from 0 (or 4095 one by one using the estimated count period Tx). Count down).

  Whether to count up or count down is distinguished according to the direction of rotation. In the present embodiment, the estimation counter 44 acquires the rotation direction determined by the decoder 41 every time a Z-phase pulse is generated. Then, based on the acquired rotation direction, the count is incremented from 0 for forward rotation, and is counted down from 4095 for reverse rotation. Then, the counter value is output to the decoder 41 as an estimated counter value.

  As described above, the estimation counter 44 estimates the estimated count period Tx for one period until the next Z-phase pulse is generated based on the latest two periods TA and TB every time the Z-phase pulse is generated. Calculate. Then, until the next Z-phase pulse is generated, the counter value is counted up (or counted down) in the calculated estimated count period Tx (that is, the rotation angle φ is 1 / in the estimated count period Tx). The estimated counter value (corresponding to the estimated rotation angle of the present invention) is output. Generation and output of the estimated counter value by the estimated counter 44 are always performed while the monitoring microcomputer 40 is operating.

Various estimation calculation methods for the estimated count period Tx are conceivable. For example, the calculation may be performed by simply dividing the previous period TA by 2 ^M , or conversely, the motor 1 from each period of the past three periods or more. You may calculate the value in which the change tendency of the rotation speed was more reflected. Also, in the case of calculating from each period for the past two periods, it is not essential to use the two most recent periods as in the present embodiment. However, in order to calculate the estimated count period Tx that better reflects the current change tendency of the rotation speed of the motor 1 while suppressing the calculation processing load, it is based on the period of the two most recent periods as in this embodiment. It is preferable to perform an estimation calculation.

  The angle signal monitoring unit 43 determines whether there is an abnormality in the A, B, Z phase signals input from the control microcomputer 30, and when any one or two abnormality is determined, an angle signal diagnosis indicating the fact is performed. The data is output to the decoder 41 and the control microcomputer monitoring unit 42. The specific contents of the angle signal abnormality determination by the angle signal monitoring unit 43 will be described in more detail.

  First, the abnormality determination of the Z-phase signal will be described. As shown in FIG. 2A, if the Z-phase signal is normal, a Z-phase pulse is generated every time the motor 1 makes one electrical rotation. However, as illustrated in FIG. 2B, for some reason, there is a possibility that an abnormality in which a Z-phase pulse does not occur (hereinafter also referred to as “Z-phase abnormality”) may occur even when the timing to be originally generated arrives. is there.

The angle signal monitoring unit 43 determines such a Z-phase abnormality based on the counter value of the edge counter based on the A and B phase signals. That is, when the edge counter is counted up (during forward rotation), a Z-phase pulse is generated at or near the timing when the counter value is counted up from 2 ^M −1 (4095 in this example) to 0. If not, it is determined that the Z phase is abnormal. More specifically, in the present embodiment, the Z-phase pulse is generated during the period from the timing when the counter value of the edge counter is counted up to 2 ^M −1 until the timing when the counter value is counted up to 0 and further counted up to 1. If it does not occur, it is determined that the Z phase is abnormal. Note that determination of Z-phase abnormality may be made at the timing when the counter value becomes zero.

When the edge counter is counted down (during reverse rotation), it is determined that the Z phase is abnormal when no Z phase pulse is generated near the timing when the counter value is counted down from 1 to 0. More specifically, in the present embodiment, the Z-phase pulse is generated during a period from the timing when the counter value of the edge counter is counted down to 0 to the timing when it is counted down to 2 ^M −1 and further counted down to 2 ^M −2. If it does not occur, it is determined that the Z phase is abnormal. Even during reverse rotation, the Z-phase abnormality may be determined at the timing when the counter value is counted down to zero.

In the example of FIG. 2B, when the motor 1 is rotating forward, the Z-phase pulse is not generated at the timing ta when the counter value of the edge counter is counted up from 2 ^M −1 to 0, and the counter Since the Z-phase pulse does not occur even when the timing tb when the value is counted up from 0 to 1, it is determined that the Z-phase abnormality has occurred at the timing tb. Note that the timing for determining the Z-phase abnormality can be appropriately determined as long as it is possible to determine that the Z-phase pulse is to be generated but not stopped.

  When the angle signal monitoring unit 43 determines that the Z-phase abnormality has occurred, the angle signal monitoring unit 43 outputs a diagnosis Z indicating the Z-phase abnormality in the angle signal diagnosis to the decoder 41 and the control microcomputer monitoring unit 42 as diagnosis information. However, in the present embodiment, when it is determined that a Z-phase abnormality has occurred, the diagnosis Z is not output immediately, and it is determined whether there is an abnormality in either the A-phase signal or the B-phase signal, and the determination result An angle signal diagnostic including the above is output.

  The determination of Z-phase abnormality based on the counter value of the edge counter by the angle signal monitoring unit 43 may be performed by acquiring the counter value from the edge counter provided in the decoder 41. However, in the present embodiment, the angle signal monitoring unit 43 itself includes an edge counter similar to the decoder 41, and this edge counter detects the rising edges of the pulses of the A and B phase signals input to the angle signal monitoring unit 43. The falling edge is detected and counted up or down. Then, based on the count value of the edge counter provided in itself, the presence / absence of Z-phase abnormality is determined.

  When the diagnosis signal Z is input from the angle signal monitoring unit 43, the decoder 41 switches the decoding method from the normal decoding method Do to the abnormal time decoding method Dz. This abnormal-time decoding method Dz is a decoding method corresponding to the diagnosis Z, and performs decoding using an A-phase signal and a B-phase signal which are normal angle signals other than the Z-phase signal.

  Specifically, the decoder 41 continues to count up or count down the edge counter based on the A and B phase signals. Hereinafter, the counter value of the edge counter based on the A and B phase signals is also referred to as a “specified count value”. When the diagnosis Z is input, the decoder 41 outputs the specified count value as a final decoding result, that is, the rotation angle φ.

  Therefore, when the diagnosis Z is input, the decoder 41 can continuously output the rotation angle φ according to the specified count value by the edge counter. It is also possible to detect the rotation direction based on the phase difference between the A and B phases, and to switch the count up and down of the edge counter according to the detected rotation direction. However, since the Z phase is abnormal, the count value of the edge counter cannot be reset based on the Z phase signal.

  Next, abnormality determination of both the A phase signal and the B phase signal will be described. As illustrated in FIG. 2C, there is a possibility that an abnormality in which neither the A-phase signal nor the B-phase signal generates a pulse (hereinafter also referred to as “AB both-phase abnormality”) may occur due to some factor. In other words, the AB both-phase abnormality is a state in which the A and B phase signals are both fixed at the H level (hereinafter “H fixed”) or fixed at the L level (hereinafter “L fixed”).

  The angle signal monitoring unit 43 determines such AB both-phase abnormality based on the Z-phase signal. That is, the angle signal monitoring unit 43 does not generate any pulses of the A and B phase signals within the period of one cycle of the Z phase signal from the generation of the Z phase pulse to the next generation of the Z phase pulse again. In the case of AB, it is determined that the AB phase is abnormal. Then, when it is determined that an AB both-phase abnormality has occurred, a diagnosis AB indicating an abnormality in both AB phases of the angle signal diagnosis is output to the decoder 41 and the control microcomputer monitoring unit 42 as the diagnosis information.

  In the example of FIG. 2C, when the Z-phase pulse is generated at the timing ta when the motor 1 is rotating forward, from the previous Z-phase pulse generation to the Z-phase pulse generation at the current timing ta. Since no pulses of the A and B phases occurred in the meantime, it is determined that the AB phase is abnormal at the timing ta.

  When the diagnosis AB is input from the angle signal monitoring unit 43, the decoder 41 switches the decoding method from the normal decoding method Do to the abnormal time decoding method Dab. This abnormal time decoding method Dab is a decoding method corresponding to the diagnosis AB, and performs decoding based on a Z-phase signal which is a normal angle signal other than the A and B phase signals.

  Specifically, the decoder 41 outputs the estimated counter value from the estimated counter 44 as the final decoding result, that is, the rotation angle φ. Thus, the control microcomputer monitoring unit 42 monitors the control microcomputer 30 based on the output rotation angle φ, that is, the estimated counter value estimated by the estimation counter 44.

  Thus, the decoder 41 can continuously output the rotation angle φ based on the estimated counter value from the estimated counter 44 when the diagnosis AB is input. However, since the rotation angle φ in this case is based on the estimated counter value, an error from the actual rotation angle may occur. Further, when the AB phase is abnormal, the rotational direction cannot be determined based on the phase difference between the A and B phase signals. Therefore, when the diagnosis AB is input, the decoder 41 keeps the rotation direction (the rotation direction when the phases A and B are normal) determined before the input is input. That is, even after the diagnosis AB is input, it is estimated that the motor 1 rotates in the same rotation direction as the latest rotation direction determined before the diagnosis AB is input. Therefore, the estimation counter 44 does not change its counting method (count up or count down) before and after the diagnosis AB is input to the decoder 41.

  The control microcomputer monitoring unit 42 needs the rotational speed of the motor 1 when calculating the current command value for each of the d and q axes from the torque command value. The control microcomputer monitoring unit 42 normally calculates the rotation speed based on the change in the rotation angle φ from the decoder 41, but calculates the Z-phase pulse generation timing when the AB phase is abnormal. Specifically, from the timing at which the previous Z-phase pulse was generated (timing at which the rotation angle φ was previously reset to 0) to the timing at which the current Z-phase pulse was generated (timing at which the rotation angle φ was reset to 0 again). The rotation speed is calculated based on the elapsed time. The control microcomputer monitoring unit 42 inputs the Z-phase signal directly or indirectly through a buffer or the like, and calculates the rotation speed based on the input Z-phase signal when the AB phase is abnormal. Also good.

  Next, the abnormality determination of either the A phase signal or the B phase signal will be described. As illustrated in FIG. 3, there is a possibility that an abnormality in which no pulse is generated in one of the A-phase signal and the B-phase signal may occur due to some factor. Hereinafter, an abnormality in which a pulse of the A phase signal does not occur is referred to as “A phase abnormality”, and an abnormality in which the pulse of the B phase signal does not occur is referred to as “B phase abnormality”. In other words, the A phase abnormality is a state in which the A phase signal is fixed to H or L, and the B phase abnormality is in other words, the state in which the B phase signal is fixed to H or L.

  The angle signal monitoring unit 43 determines an A phase abnormality or a B phase abnormality by comparing the A and B phase signals. Here, as an example, a method for determining a B phase abnormality when a B phase abnormality occurs will be described with reference to FIG. However, it is assumed that the motor 1 is rotating forward.

  FIG. 3 shows an example in which a B-phase abnormality (fixed to H of the B-phase signal in this example) occurs at time tb after the A-phase signal pulse rises at time ta. If it is normal, the B phase signal should fall at time tc after the A phase signal rises at time ta. However, since a B-phase abnormality has occurred at time tb prior to time tc, the B-phase signal does not fall at time tc.

  Therefore, if it is normally normal, the decoder 41 should count up the counter value of the edge counter to 5 at time ta and then count up the edge counter value to 6 at the time tc due to the fall of the B phase signal. The counter value remains at 5 without counting up. Therefore, even after time tc, the rotation angle φ output by the decoder 41 remains at 5.

  If the B-phase signal falls at time td without the B-phase signal falling (maintained at the H level) at time tc, the decoder 41 determines that the B-phase signal is at the H level at time td. Therefore, it is determined that the rotation direction of the motor 1 has changed to reverse rotation. Therefore, the counting method of the edge counter is switched from counting up to counting down. Thereby, the counter value (specified count value) of the edge counter is counted down from 5 to 4 at time td. Therefore, the rotation angle φ output from the decoder 41 is also 4.

  After that, if the rotation is actually reverse and the B-phase signal is normal, the B-phase signal should fall after the A-phase signal falls at time td. However, in this example, since the reverse rotation is not actually performed and the B-phase signal remains at the H level, the A-phase signal rises again at time te after time td.

  Then, at this time te, the decoder 41 determines that the rotation direction of the motor 1 has changed from the reverse rotation to the forward rotation again because the A phase signal has risen while the B phase signal is at the H level. Therefore, the counting method of the edge counter is switched from countdown to countup. Thereby, the decoder 41 counts up the counter value (specified count value) of the edge counter from 4 to 5 at time te.

  On the other hand, the angle signal monitoring unit 43 also includes an edge counter as described above, and performs edge counting while discriminating the rotation direction in the same manner as the decoder 41. Therefore, reverse rotation determination at time Td and forward rotation determination at time te are also performed in the same manner as the decoder 41.

  Then, since the rotation direction is continuously switched every time an edge change occurs at the time te, the angle signal monitoring unit 43 does not actually change the rotation direction but the B-phase signal is fixed to H. Judge that there is. That is, the angle signal monitoring unit 43 continuously changes the edge direction every time the edge changes, such as forward rotation → reverse rotation → forward rotation or reverse rotation → forward rotation → reverse rotation. The abnormality of the signal that is not present (H fixed or L fixed) is determined. In other words, if the edge change of the other pulse signal does not occur during the period in which one edge change has occurred three times in succession (time ta to time te in the example of FIG. 3), the other is determined to be abnormal. To do. Note that “three times” is an example, and may be four times or more. That is, when the other edge change does not occur during a period in which one edge change occurs four or more times continuously, the other may be determined as abnormal.

  In the example of FIG. 3, the angle signal monitoring unit 43 determines that the B phase signal is fixed to H, that is, the B phase abnormality at time te. Then, to the decoder 41 and the control microcomputer monitoring unit 42, the diagnosis B indicating the B phase abnormality is output as the diagnosis information.

  When the diagnosis B is input from the angle signal monitoring unit 43, the decoder 41 switches the decoding method from the normal decoding method Do to the abnormal time decoding method Db. This abnormal time decoding method Db is a decoding method corresponding to the diagnosis B, and is based on performing decoding based on the A phase signal which is a normal angle signal among the A and B phase signals, and appropriately estimating the estimation counter. Interpolation by the estimated counter value from 44 is also performed. The rotation angle φ is reset to 0 every time the Z-phase pulse is generated as in the normal state.

  Specifically, the decoder 41 corrects the counter value of the edge counter and thereafter increments the count by the edge counter by two every time an edge change of the A-phase signal occurs. That is, if the B-phase signal is normal, the counter value (specified count value) of the edge counter should be 9 at time te. That is, after the counter value is counted up to 5 at time ta, it should have been increased by 4 counts. However, the counter value is set to 5 at the time te because it is erroneously determined as a change in the rotation direction as described above.

  Therefore, the decoder 41 once sets the counter value to 5 at time te, but further adds 4 to the counter value to 9 by the diagnosis B input from the angle signal monitoring unit 43. That is, the counter value is updated to a normal value. Then, the updated value (9) is output as the rotation angle φ at time te. After the time te, every time the edge change of the A phase signal occurs, the counter value of the edge counter is incremented by two. The counter value of the edge counter that is incremented by two after this time te is also referred to as “anomalous count value”.

  In the example of FIG. 3, when the diagnosis B is input at time te, the decoder 41 switches the decoding method to the abnormal time decoding method Db, and thereby the counter value of the edge counter is generated every time the edge change of the A phase signal occurs. An example is shown in which (anomalous count value) is counted up by two from 9 → 11 → 13 →. Basically, these two skip values are output as the rotation angle φ.

  However, the angle resolution of the rotation angle φ that is output in two skips is halved compared to the normal time. Of course, the control microcomputer monitoring unit 42 can monitor the control microcomputer 30 even when the rotation angle φ with the reduced resolution is used. However, in order to perform the monitoring function more sufficiently, the rotation angle φ The resolution should be as high as possible.

  Accordingly, the decoder 41 of this embodiment performs interpolation of the decoded output using the estimated counter value when the B phase is abnormal. That is, the decoder 41 switches the counting method of the edge counter to two skips due to the B phase abnormality and then counts up from n to n + 2 (that is, the irregular count value is n). When the estimated counter value changes from n to n + 1), the irregular count value is n, but the rotation angle φ to be finally output is n + 1 giving priority to the estimated count value. is there. After that, when the irregular count value is counted up to n + 2, the rotation angle φ that is finally output is also returned to the irregular count value n + 2.

  In the example of FIG. 3, the B-phase abnormality is determined at time te, and thereby the counter value (anomalous count value) of the edge counter becomes 9. Thereafter, the irregular count value remains 9 until time tf when the edge change of the A phase signal occurs, and is incremented to 11 when the edge change of the A phase signal occurs at time tf.

  On the other hand, during this time te to time tf, the estimated counter value from the estimated counter 44 changes from 9 to 10 at time tx. Therefore, the decoder 41 sets the rotation angle φ to be finally output to 10 at this time tx. Similarly, from the time when the irregular count value is counted up to 11 at time tf until the time when the irregular count value is counted up to 13 at time tg, the irregular count value is basically output as the rotation angle φ. However, since the estimated counter value has changed from 11 to 12 at time ty, the rotation angle φ that is finally output at time ty is also 12.

  That is, the angular resolution is increased by interpolating the irregular count value based on the edge change of the A phase signal with the estimated counter value. If the estimated counter value does not become n + 1 while the irregular count value changes from n to n + 2, interpolation using the estimated counter value is not performed.

  As described above, the abnormal-time decoding method Db, which is a decoding method when the B-phase is abnormal, is based on the use of the irregular counter value (two skipped values) based on the A-phase signal, and the estimated counter from the estimated counter 44. Interpolation by value is also performed. Moreover, about the rotation direction, the rotation direction before it is judged as B phase abnormality is hold | maintained. That is, when the B phase signal is abnormal, the rotation direction cannot be determined based on the phase difference between the A and B phase signals. Therefore, the rotation direction determined before the B-phase abnormality is determined, that is, the rotation direction determined immediately before the diagnosis B is input from the angle signal monitoring unit 43 (forward rotation in this example) is also applied thereafter. Use as is.

  FIG. 3 illustrates the case where the B-phase abnormality occurs when the motor 1 is rotating forward. However, the determination of the B-phase abnormality is basically performed in the same manner when the motor 1 is rotating backward. I do. The main difference between the reverse rotation and the forward rotation is that each counter is counted down, and accordingly, when the diagnosis B is input, the decoder 41 subtracts 4 from the count value (specified count value) at that time. And updating the count value.

  Further, the determination of the A phase abnormality can be performed in the same manner as the determination of the B phase abnormality. That is, when there is no change in the edge of the A phase signal and the rotation direction is continuously switched from forward rotation → reverse rotation → forward rotation or reverse rotation → forward rotation → reverse rotation every time the edge of the B phase signal changes. Next, it is determined whether the A phase is abnormal (A phase signal is fixed to H or L). When the angle signal monitoring unit 43 determines that the A phase abnormality has occurred, the angle signal monitoring unit 43 outputs a diagnosis A indicating the A phase abnormality in the angle signal diagnosis to the decoder 41 and the control microcomputer monitoring unit 42 as diagnosis information.

  When the diagnosis A is input from the angle signal monitoring unit 43, the decoder 41 switches the decoding method from the normal decoding method Do to the abnormal time decoding method Da. This abnormal-time decoding method Da is a decoding method corresponding to the diagnosis A, and is based on performing decoding based on the B phase signal which is a normal angle signal among the A and B phase signals, and appropriately estimating the counter. Interpolation by the estimated counter value from 44 is also performed.

  Specifically, the decoder 41 corrects the counter value of the edge counter (+4 or −4) as in the case of the B phase abnormality, and thereafter counts the edge counter every time an edge change of the B phase signal occurs. Count up by two. Further, as in the case of B-phase abnormality, interpolation is also performed if interpolation based on the estimated counter value is possible.

  In addition, when the Z-phase abnormality is determined, the angle signal monitoring unit 43 further determines whether the A-phase signal or the B-phase signal is normal. As described above, the Z-phase abnormality is determined based on whether or not a Z-phase pulse is generated in the vicinity of the timing at which the edge counter is switched to 0. If it is determined that there is a Z-phase abnormality, the presence or absence of an A-phase abnormality or a B-phase abnormality is subsequently performed by the method described above (the method described with reference to FIG. 3) based on the A and B phase signals.

  That is, if it is determined that the Z phase is abnormal, and the edge changes of the A and B phase signals continue alternately a predetermined number of times, the diagnosis Z is output assuming that the A and B phase signals are normal. On the other hand, after the determination of the Z-phase abnormality, the edge changes of the A and B phase signals do not continue alternately for a predetermined number of times, for example, the B phase signal is fixed to H or L and only the edge change of the A phase signal occurs. If this happens, the B phase abnormality is also determined in the manner described above (see FIG. 3). That is, as a result, both the B-phase signal and the Z-phase signal are determined to be abnormal (hereinafter also referred to as “BZ both-phase abnormality”).

  When the angle signal monitoring unit 43 determines that the BZ both-phase abnormality is present, the angle signal monitoring unit 43 outputs a diagnosis BZ indicating the BZ both-phase abnormality in the angle signal diagnosis to the decoder 41 and the control microcomputer monitoring unit 42.

  When the diagnosis BZ is input from the angle signal monitoring unit 43, the decoder 41 switches the decoding method from the normal decoding method Do to the abnormal time decoding method Dbz. This abnormal-time decoding method Dbz is a decoding method corresponding to the diagnosis BZ, and performs decoding using an A phase signal which is a normal angle signal other than the B and Z phase signals. That is, in the same way as the counter value (anomalous count value) after time te in FIG. 3, when the diagnosis BZ is input, first, the counter value (specified counter value) of the edge counter at that time is a normal value. (+4 or -4). Each time an edge change occurs in the A-phase signal, the edge counter is incremented by two (or counted down). Therefore, when both BZ phases are abnormal, an irregular count value based on the A phase signal is output as the rotation angle φ.

  Further, after the determination of the Z-phase abnormality, the edge changes of the A and B phase signals do not continue alternately for a predetermined number of times, for example, the A phase signal is fixed to H or fixed to L and only the edge change of the B phase signal occurs. If this happens, the phase A abnormality is also judged. That is, as a result, it is determined that both the A-phase signal and the Z-phase signal are abnormal (hereinafter also referred to as “AZ both-phase abnormality”).

  When the angle signal monitoring unit 43 determines that the AZ phase abnormality has occurred, the angle signal monitoring unit 43 outputs a diagnosis AZ indicating the AZ phase abnormality in the angle signal diagnosis to the decoder 41 and the control microcomputer monitoring unit 42.

  When the diagnosis AZ is input from the angle signal monitoring unit 43, the decoder 41 switches the decoding method from the normal decoding method Do to the abnormal time decoding method Daz. This abnormal-time decoding method Daz is a decoding method corresponding to the diagnosis AZ, and performs decoding using a B-phase signal that is a normal angle signal other than the A and Z phase signals. That is, in the same manner as the above-described BZ both-phase abnormality, when the diagnosis AZ is input, first, the counter value (specified counter value) of the edge counter at that time is updated to a normal value (+4 or −4 ). Then, every time an edge change of the B phase signal occurs, the edge counter is counted up (or counted down) by two. Therefore, when both AZ phases are abnormal, the irregular count value based on the B phase signal is output as the rotation angle φ.

  Up to this point, the angle signal abnormality determination method by the angle signal monitoring unit 43 and the angle signal decoding method by the decoder 41 have been described, but these methods can be summarized as shown in FIGS. 4 and 5. it can. The angle signal abnormality determination operation (determination of various abnormalities described above) shown in FIG. 4 is performed by the angle signal monitoring unit 43, and the decoding method setting operation (switching of various decoding methods described above) shown in FIG. 41, which are not software processing, but in FIG. 4 and FIG. 5, the operation of the corresponding hardware is schematically represented in a flowchart format.

  As shown in FIG. 4, the angle signal monitoring unit 43 first determines in S110 whether or not the vehicle speed is equal to or higher than a certain speed based on the vehicle speed signal input from the EV ECU 9. If the vehicle speed is not equal to or greater than a certain speed (S110: NO), the angle signal abnormality determination operation is terminated. That is, when the vehicle speed is lower than a certain speed, the abnormality determination of the angle signal is not performed.

  If the vehicle speed is equal to or higher than a certain speed (S110: YES), in S120, it is determined whether both the A-phase signal and the B-phase signal are H-fixed or L-fixed, that is, whether the AB phase is abnormal. If it is determined that both AB phases are abnormal, the diagnosis AB is output to the decoder 41 in S180.

  If it is not AB both-phase abnormality, it progresses to S130 and judgment of Z-phase abnormality is performed. That is, in S130, it is determined whether or not the counter value of the edge counter included in the angle signal monitoring unit 43 itself has become zero. When the counter value of the edge counter becomes 0, it is determined in S140 whether or not the edge of the Z-phase signal has risen. If the edge of the Z-phase signal does not rise, it is determined that the Z-phase is abnormal, and the process proceeds to S190. In S190, it is determined whether the A-phase signal is H-fixed or L-fixed, that is, whether the A-phase is abnormal. If it is determined that the phase A is abnormal, the diagnosis AZ is output to the decoder 41, including the case where the phase Z is abnormal.

  If the A-phase signal is normal in S190, the process proceeds to S210, and it is determined whether the B-phase signal is H-fixed or L-fixed, that is, whether the B-phase is abnormal. If it is determined that the phase B is abnormal, the diagnosis BZ is output to the decoder 41, including the case where the phase Z is abnormal. If the B phase signal is also normal in S210, the process proceeds to S230, and the diagnosis Z is output to the decoder 41.

  When the counter value of the edge counter is not 0 in S130, and when the edge of the Z-phase signal rises in S140, the process proceeds to S150. In S150, the presence or absence of the A phase abnormality is determined in exactly the same manner as in S190. If it is determined that the phase A is abnormal, the diagnosis A is output to the decoder 41 in S240. If the A-phase signal is normal, the process proceeds to S160, and the presence or absence of the B-phase abnormality is determined in the same manner as in S210. If it is determined that the phase B is abnormal, the diagnosis B is output to the decoder 41 in S250. If the B phase signal is normal, it is determined in S170 that all the A, B, and Z phase signals are normal, and the process returns to S110.

  Next, as shown in FIG. 5, the decoder 41 first determines whether or not an angle signal diagnosis is input from the angle signal monitoring unit 43 in S310. If there is no input of the angle signal diagnosis, in S320, the A, B, Z phase signals are decoded by the normal decoding method Do, and the rotation angle φ is generated and output.

  When the angle signal diagnosis is input, the determination of the type of diagnosis and the switching to the decoding method corresponding to the diagnosis are performed after S330. That is, in S330, it is determined whether or not the input angle signal diagnosis is the diagnosis A. If it is diagnosis A, the decoding method is switched to the abnormal decoding method Da in S340. The details of the abnormal decoding method Da are as described above. That is, the normal rotation direction before being determined as abnormal is maintained. Then, based on outputting the irregular count value counted based on the B phase signal as a decoding result (rotation angle φ), the interpolation is also executed if interpolation based on the estimated counter value based on the Z phase signal is possible.

  If it is determined in S330 that it is not the diagnosis A, it is determined whether or not the input angle signal diagnosis is the diagnosis B in S350. If it is the diagnosis B, the decoding system is switched to the abnormal decoding system Db in S360. The details of the abnormality decoding method Db are as described above. That is, the normal rotation direction before being determined as abnormal is maintained. Then, based on outputting the irregular count value counted based on the A phase signal as a decoding result (rotation angle φ), the interpolation is also executed if the interpolation based on the estimated counter value based on the Z phase signal is possible.

  If it is determined in S350 that it is not a diagnosis B, it is determined in S370 whether or not the input angle signal diagnosis is a diagnosis AB. If it is a diagnosis AB, the decoding method is switched to the abnormal decoding method Dab in S380. Details of the abnormal decoding method Dab are as described above. That is, the normal rotation direction before being determined as abnormal is maintained. Then, an estimated counter value based on the Z-phase signal is output as a decoding result (rotation angle φ).

  If it is determined in S370 that the diagnosis is not a diagnosis AB, it is determined in S390 whether or not the input angle signal diagnosis is a diagnosis AZ. If it is the diagnosis AZ, the decoding method is switched to the abnormal decoding method Daz in S400. The details of the abnormal decoding method Daz are as described above. That is, the normal rotation direction before being determined as abnormal is maintained. Then, the irregular count value based on the B phase signal is output as a decoding result (rotation angle φ).

  If it is determined in S390 that it is not a diagnosis AZ, it is determined in S410 whether or not the input angle signal diagnosis is a diagnosis BZ. If it is a diagnosis BZ, the decoding method is switched to the abnormal decoding method Dbz in S420. The details of the abnormal decoding method Dbz are as described above. That is, the normal rotation direction before being determined as abnormal is maintained. Then, the irregular count value based on the A-phase signal is output as a decoding result (rotation angle φ).

  If it is determined in S410 that it is not the diagnosis BZ, the decoding method is switched to the abnormal time decoding method Dz in S430. The details of the abnormality decoding method Dz are as described above. That is, a specified count value based on the A and B phase signals is output as a decoding result (rotation angle φ).

  Next, monitoring control processing by the control microcomputer monitoring unit 42 in the monitoring microcomputer 40 will be described with reference to FIG. As described above, the entity of the control microcomputer monitoring unit 42 is a CPU. After the operation starts, the CPU executes the monitoring control processing program of FIG. 6 stored in the ROM or the like at a predetermined control cycle (current sampling cycle).

  When the control microcomputer monitoring unit 42 (CPU) starts the monitoring control process of FIG. 6, first, in S510, current sampling is performed. That is, each current signal from each current sensor 25 to 27 is read. In step S520, it is determined whether an angle signal diagnosis is input from the angle signal monitoring unit 43.

  If the angle signal diagnosis is not input in S520, the process proceeds to S530 and the control microcomputer monitoring process is performed. That is, as described above, based on the rotation angle φ from the decoder 41, the current signals from the current sensors 25, 26 and 27, and the torque command value from the EV ECU 9, whether or not the control microcomputer 30 is operating normally. It is monitored. In S540, it is determined whether or not the control microcomputer 30 is abnormal. If the control microcomputer 30 is abnormal, a control microcomputer abnormality diagnosis indicating that fact is stored in its own RAM (SRAM) and notified to the EV ECU 9. To do.

  On the other hand, if the angle signal diagnosis is input in S520, the input diagnosis is stored and the diagnosis is notified to the EV ECU 9 in S560. As a result, the EV ECU 9 performs the aforementioned angle signal abnormality handling process. In step S570, it is determined whether or not the input diagnosis is the diagnosis Z.

  If it is not a diagnosis Z, the process proceeds to S530. If it is a diagnosis Z, the process proceeds to S580. The processing of S580 to S600 is confirmation processing of the reference position of the rotation angle in the case of Diag Z.

  As described above, when the diagnosis Z is input (that is, when the Z-phase abnormality has occurred), the decoder 41 performs decoding by the abnormal-time decoding method Dz, but in this case, the Z-phase signal is abnormal. For this reason, counting of the edge counter based on the A and B phase signals is continued and the rotation angle can be detected, but the reference position cannot be confirmed, that is, the counter value cannot be reset based on the Z phase pulse. Therefore, if for some reason the timing at which the counter value of the edge counter becomes 0 deviates significantly from the timing at which the Z-phase pulse is supposed to be generated, the control microcomputer monitoring unit 42 causes the inaccurate angle information (rotation angle φ ) Is used to monitor the control microcomputer 30, which is not very preferable.

  Therefore, when the diagnosis Z is input, the control microcomputer monitoring unit 42 confirms the reference position by comparing the U-phase current and the phase of the rotation angle φ in S580 to S600. In other words, it is confirmed whether or not the rotation angle φ is different from the actual rotation angle.

  That is, in S580, it is determined whether or not the rotation angle φ from the decoder 41 is 0 degrees (for example, count value 0) or 180 degrees (for example, count value 2047). If it is either 0 degrees or 180 degrees, it is determined in S590 whether the U-phase current is 0 or in the vicinity thereof.

  As shown in FIG. 7, if the rotation angle φ is normal, each phase current and the rotation angle φ periodically change in a synchronized state. In the present embodiment, when the U-phase current becomes approximately 0, the rotation angle of the motor 1 is configured to be 0 degree or 180 degrees. Therefore, the reference position of the rotation angle φ from the decoder 41 is actually determined by checking whether or not the rotation angle φ from the decoder 41 is 0 degree or 180 degrees when the U-phase current becomes almost zero. Therefore, it is possible to confirm whether the rotation angle φ from the decoder 41 is sufficiently reliable.

  In S590, if the U-phase current is almost 0, it is determined that the reference position of the rotation angle φ is correct, and the process proceeds to S530. On the other hand, if the U-phase current cannot be regarded as 0 or in the vicinity thereof in S590, in S600, the EVECU 9 is informed that the reference position of the rotation angle φ is not correct (in other words, the rotation angle φ is the actual rotation angle). A message α indicating that the difference is different from As a result, the EV ECU 9 performs a predetermined abnormality handling process corresponding to the diagnosis α. Various abnormality handling processes are conceivable. For example, the driver may simply be notified that an abnormality has occurred, or the vehicle may be urgently stopped.

  Note that the diagnosis α is output on the premise that the diagnosis Z is output separately due to the Z-phase abnormality. Therefore, when the diagnosis α is output, an abnormality handling process corresponding to both diagnosis is performed together with the separately output diagnosis Z.

  According to the present embodiment described above, the decoder 41 generates the rotation angle φ using another normal signal even if any one or two of the A, B, and Z phase signals become abnormal. can do. For this reason, the control microcomputer monitoring unit 42 performs control based on the rotation angle φ having a desired (minimum) reliability as long as all three are not abnormal even if abnormality occurs in each of the A, B, and Z phase signals. The monitoring operation of the microcomputer 30 can be continued for a minimum necessary period (for example, a period required for evacuation travel).

  Further, an estimation counter 44 that performs angle estimation based on the Z-phase signal is provided, and when an AB both-phase abnormality occurs, the estimation counter value of the estimation counter 44 is output as the rotation angle φ. In the case of an A-phase abnormality or a B-phase abnormality, it is also used for interpolation (see the lowermost stage in FIG. 3). As described above, when the estimated counter value is used for interpolation in the case of the A-phase abnormality or the B-phase abnormality, the rotation angle φ with higher resolution can be obtained even in the abnormal state.

  Further, in the case of Z-phase abnormality, the reference position cannot be confirmed based on the Z-phase pulse, but in this embodiment, the counter value of the edge counter based on the A and B phase signals and the phase of the U-phase current are compared. Thus, it is determined whether or not the reference position of the rotation angle φ indicated by the counter value of the edge counter is correct, that is, whether or not the rotation angle φ matches the actual rotation angle. For this reason, when the Z-phase abnormality occurs, if the rotation angle φ based on the A and B phase signals has become inconsistent with the actual situation, that fact is accurately detected, so that the EV ECU 9 can take appropriate and prompt action. Can take.

[Modification]
Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention. Needless to say.

  In the above embodiment, when the A-phase signal or the B-phase signal becomes abnormal, the decoder 41 keeps the normal rotation direction immediately before it is determined to be abnormal, and continues to rotate in that rotation direction thereafter. Counting continued as a thing. However, after it is determined that there is an abnormality, the rotation direction may actually change. Therefore, in the electric vehicle, if any signal or information that can determine the rotation direction of the motor 1 other than the A and B phase signals can be acquired, the decoder 41 can correctly count based on the acquired rotation direction. it can.

  In the present embodiment, a shift position signal is input to the EV ECU 9. This shift position signal is a signal indicating the position of the shift lever. Normally, when the shift position is R (reverse), the motor 1 rotates in the direction of moving the vehicle backward. Conversely, when the shift position is other than R, P (parking), and N (neutral), the vehicle is It can be determined that the motor 1 rotates in the forward direction.

  Therefore, the shift position signal is transmitted from the EVECU 9 to the MGECU 7, and the control microcomputer monitoring unit 42 in the monitoring microcomputer 40 determines the rotation direction of the motor 1 based on the transmitted shift position signal. Good.

Further, even if there is no specific signal such as a shift position signal, the control microcomputer monitoring unit 42 can determine the rotation direction using the torque command value and each current signal.
In the control of the motor 1 (vector control in this example), generally, the rotation angle θ of the motor 1, the U-phase current Iu, and the W-phase current Iw are used as shown in the following equations (3) and (4). Q The actual current values Id and Iq of each axis are obtained.

一方、トルク指令値についても、ｄ・ｑ各軸の電流指令値ＩｄｃｏｍおよびＩｑｃｏｍに変換される。そして、各電流指令値ＩｄｃｏｍおよびＩｑｃｏｍと、各実電流値Ｉｄ，Ｉｑとの差に基づくフィードバック制御により、モータ１が制御される。

On the other hand, the torque command value is also converted into current command values Idcom and Iqcom for each of the d and q axes. The motor 1 is controlled by feedback control based on the difference between the current command values Idcom and Iqcom and the actual current values Id and Iq.

  Therefore, when the rotation angle φ changes from a certain angle φ0 by d, it changes by d by forward rotation (that is, the rotation angle φ becomes φ0 + d) or by d by reverse rotation (that is, the rotation angle φ changes by φ0). -D) is determined using the above equation (4).

  Specifically, when the rotation angle φ is changed from φ0 by d, the q-axis current Iq (φ0 + d) is assumed to be φ0 + d, and q is assumed to be φ0−d. The shaft current Iq (φ0−d) is calculated using the above equation (4). That is, in the above equation (4), the respective calculation results are obtained when φ is φ0 + d and φ0−d. At that time, as for Iu and Iw in the above formula (4), values at the time when the rotation angle φ changes from φ0 by d is used.

On the other hand, the q-axis current command value Iqcom is also calculated based on the torque command value when the rotation angle φ is φ0.
Then, the absolute values ra and rb of the difference between the calculated q-axis current command value and the q-axis currents Iq (φ0 + d) and Iq (φ0−d) are expressed by the following equations (5) and (6), respectively. Ask.

そして、各絶対値ｒａ，ｒｂのうち小さい方の回転角が、正しい回転角であると判断できる。例えばｒａ＜ｒｂであった場合は、φ０＋ｄが正しい回転角、即ちモータ１は順回転しているものと判断できる。逆に、ｒａ＞ｒｂであった場合は、φ０−ｄが正しい回転角、即ちモータ１は逆回転しているものと判断できる。このように、制御マイコン監視部４２は、上記式（５）、（６）を用いた演算により、回転方向を判別することができるのである。

Then, it can be determined that the smaller rotation angle of the absolute values ra and rb is the correct rotation angle. For example, when ra <rb, it can be determined that φ0 + d is the correct rotation angle, that is, the motor 1 is rotating forward. Conversely, if ra> rb, it can be determined that φ0-d is the correct rotation angle, that is, the motor 1 is rotating in the reverse direction. Thus, the control microcomputer monitoring unit 42 can determine the rotation direction by the calculation using the above formulas (5) and (6).

  Therefore, when the A-phase signal or the B-phase signal becomes abnormal and a diagnosis indicating one (diagonal A, B, AB, AZ, BZ) is input, the control microcomputer monitoring unit 42 receives the shift position signal. Thus, if there is an input of any signal or the like that can determine the rotation direction, the rotation direction is determined using the signal or the like, and the result may be output to the decoder 41. If there is no input of such a signal or the like, the rotation direction is determined by calculation using the above equations (5) and (6), and the result may be output to the decoder 41. The rotation direction may be determined periodically after the angle signal diagnosis is input.

  When the rotation direction determination result is input from the control microcomputer monitoring unit 42, the decoder 41 compares the rotation direction held by itself, and if it is different, the decoder 41 newly sets the input determination result as a correct one. And counting is performed based on the new rotation direction.

  In addition, the vehicle speed determination in S110 of FIG. 4 is not limited to being performed based on the vehicle speed signal from the EV ECU 9, and any other signal or the like that directly or indirectly indicates the vehicle speed is determined based on that signal. May be. Further, the control microcomputer monitoring unit 42 calculates the vehicle speed based on each current detection signal from each current sensor (that is, based on a change in the current value), and inputs the calculation result to the angle signal monitoring unit 43, The angle signal monitoring unit 43 may make the determination in S110 based on the input calculation result (vehicle speed).

  In the above embodiment, the decoder 41, the angle signal monitoring unit 43, and the estimation counter 44 are all configured by hardware. However, this is merely an example, and one or a plurality of these are assigned to the CPU. You may make it implement | achieve by the software processing by.

  Moreover, in the said embodiment, although the example which applied this invention to the monitoring microcomputer 40 of an electric vehicle was shown, it cannot be overemphasized that application of this invention is not limited to the monitoring microcomputer 40, and also to an electric vehicle. Needless to say, the application is not limited to the above.

  For example, the present invention can be applied to a motor control device configured to perform motor control based on A, B, and Z phase signals. As an example, application to a motor control device having a so-called rotary encoder that outputs A, B, and Z phase signals is conceivable. In that case, when any of the A, B, Z phase signals becomes abnormal, the rotation angle is generated by performing decoding by the corresponding abnormal decoding method based on other normal signals, The retreat traveling can be made possible by using the rotation angle. As described above, the present invention is applicable to all devices, apparatuses, and the like configured to generate the rotation angle of the rotating body based on the A, B, and Z phase signals.

  DESCRIPTION OF SYMBOLS 1 ... Motor, 3 ... Battery, 5 ... Inverter, 7 ... MGECU, 9 ... EVECU, 13 ... Resolver, 25 ... U-phase current sensor, 26 ... V-phase current sensor, 27 ... W-phase current sensor, 30 ... Control microcomputer, DESCRIPTION OF SYMBOLS 31 ... RDC, 32 ... Motor control part, 33 ... Encoder, 36 ... PWM circuit, 36 ... Pulse width modulation circuit, 40 ... Monitoring microcomputer, 41 ... Decoder, 42 ... Control microcomputer monitoring part, 43 ... Angle signal monitoring part, 44 ... Estimated counter

Claims (8)

The first and second pulse signals which are input each time the rotating body (1) rotates by a certain angle, and the rotating body is 360 degrees / n larger than the certain angle (n is 1 or more). Rotation for detecting the rotation angle while detecting the rotation direction of the rotating body by a predetermined normal detection method (S320) determined in advance using the third pulse signal input every rotation. Angle detection means (41);
Pulse signal determination means (43) for determining whether or not at least one of the pulse signals is abnormal;
With
The rotation angle detection means, when any one or two of the pulse signals is determined to be abnormal by the pulse signal determination means, is another one or two normal pulse signals that are not determined to be abnormal. The rotation angle detection device is characterized in that the rotation angle of the rotating body is detected by a predetermined abnormality detection method according to the type of the normal pulse signal. The rotation angle detection device according to claim 1,
The pulse signal determination means includes
A first determination function (S150, S160, S190, S210) for determining whether the other pulse signal is abnormal based on one of the first and second pulse signals, and the third pulse signal A second determination function (S120) for determining whether or not both of the first and second pulse signals are abnormal, and the third pulse signal based on the first and second pulse signals. Having at least one determination function of the third determination function (S140) for determining whether or not there is an abnormality;
The rotation angle detecting means includes
As the abnormality detection method, a first abnormality detection using the one pulse signal and the third pulse signal used when the other pulse signal is determined to be abnormal by the first determination function. Method (S340, S360), second abnormality detection using the third pulse signal, used when both the first and second pulse signals are determined to be abnormal by the second determination function The third abnormality detection method (S430) using the first and second pulse signals, which is used when the third pulse signal is determined to be abnormal by the method (S380) and the third determination function. ) At least in an abnormality detection method corresponding to the determination function of the pulse signal determination means. The rotation angle detection device according to claim 2,
The pulse signal determination means includes at least the first determination function,
The first determination function is used when the edge change of the other pulse signal does not occur during a period when the edge change of one of the first and second pulse signals continuously occurs a predetermined number of times or more. It is a function to judge that the pulse signal of the other is abnormal,
The rotation angle detection means includes at least the first abnormality detection method,
In the first abnormality detection method, the third pulse signal is input while maintaining the rotation direction detected by the normal detection method before the abnormality is determined by the first determination function. The rotation angle is set to an initial value every time and the relative angle change amount from the initial value is detected by using the other pulse signal to detect the relative angle change amount as the rotation angle. A rotation angle detection device characterized by that. The rotation angle detection device according to claim 3,
The rotation angle detection means sets the rotation angle to an initial value every time the third pulse signal is generated, and uses the generation cycle of the previous third pulse signal before the generation, A rotation angle estimating means (44) for estimating a rotation speed until the third pulse signal is generated again and calculating an estimated rotation angle that is a change amount from the initial value according to the estimated rotation speed;
In the first abnormality detection method, the estimated rotation angle calculated by the rotation angle estimating means is calculated while the relative angle change amount is changed from the current value to the next value by the other pulse signal. When the angle is within the range between the current value and the next value, the estimated rotation angle is detected as the rotation angle until the angle changes to the next value. A rotation angle detection device characterized by that. The rotation angle detecting device according to any one of claims 2 to 4,
The pulse signal determination means has at least the second determination function,
The second determination function is configured to detect the first and second pulse signals when an edge change of the first and second pulse signals does not occur during one period of the third pulse signal. It is a function that both sides judge as abnormal,
The rotation angle detecting means includes
Each time the third pulse signal is generated, the rotation angle is set to an initial value, and then the third pulse signal is again generated using the generation cycle of the past third pulse signal before the generation. A rotation angle estimating means for estimating a rotation speed until the occurrence of, and calculating an estimated rotation angle that is an amount of change from the initial value according to the estimated rotation speed;
As the abnormality detection method, at least the second abnormality detection method is provided,
The second abnormality detection method is calculated by the rotation angle estimation means while maintaining the rotation direction detected by the normal detection method before being determined abnormal by the second determination function. A rotation angle detection device configured to detect an estimated rotation angle as the rotation angle. The rotation angle detection device according to any one of claims 3 to 5,
Rotation direction detection means (42) for detecting the rotation direction of the rotating body by a predetermined detection method not using the first and second pulse signals,
When the rotation angle is detected by the first abnormality detection method or the second abnormality detection method, the rotation angle detection unit detects the rotation direction detected by the rotation direction detection unit. If it is different from the direction, it is determined that the rotating body is rotating in the rotation direction detected by the rotation direction detecting means, and the rotation angle is detected. The rotation angle detecting device according to any one of claims 2 to 6,
The normal detection method detects the rotation direction of the rotating body based on the phase difference between the first and second pulse signals, and sets the rotation angle to an initial value every time the third pulse signal is input. The relative angle change amount from the initial value is detected using the first and second pulse signals, and the relative angle change amount is detected as the rotation angle. ,
The pulse signal determination means has at least the third determination function,
In the third determination function, the third pulse signal is not generated at a timing when the relative angle change amount is an amount that the third pulse signal should be generated, or in a predetermined period including the timing. A function of determining that the third pulse signal is abnormal when
The rotation angle detection means includes at least the third abnormality detection method,
The third abnormality detection method is configured to detect the rotation angle while detecting the rotation direction using the first and second pulse signals. . The rotation angle detection device according to claim 7,
The rotating body is a synchronous motor (1);
Current detection means (25, 26, 27) for detecting the alternating current supplied to the synchronous motor;
When the rotation angle is detected by the rotation angle detection means by the third abnormality detection method, the detected rotation angle and the phase of the alternating current detected by the current detection means To determine whether or not the rotation angle is a value corresponding to the phase. If the rotation angle is not a corresponding value, it is determined that the rotation angle is different from the actual rotation angle. Rotation angle determination means (S580 to S600);
A rotation angle detection device comprising:

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