JP2016142693A - Resolver/digital converter abnormality detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for performing abnormality detection processing of a resolver/digital converter.SOLUTION: A resolver/digital converter (RDC) 41 obtains a rotation angle θ of a motor using a sin signal and cos signal outputted from the resolver. An analog-to-digital converter (ADC) 40 converts a motor current signal into a digital signal according to the timing that a motor current value should be acquired, and converts the sin signal and cos signal, which are outputted from the resolver, into digital signals successively to or prior to the timing. A motor angle deduction unit 45 obtains the rotation angle φ of the motor on the basis of the SIN signal value and COS signal value which have been converted into the digital signals. When a sum of a square value of the SIN signal value and a square value of the COS signal value is equal to or larger than a predetermined lower limit and equal to or smaller than a predetermined upper limit, an abnormality detection unit 46 compares the rotation angle θ with the rotation angle φ, and performs abnormality detection processing on the RDC 41.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a technique for detecting an abnormality of a resolver / digital converter.

  In recent years, hybrid vehicles and electric vehicles equipped with an electric motor as a drive source have been developed. A motor control system in a vehicle performs boost control for switching a switching element of a boost converter to boost a DC voltage of a power supply, and inverter control for switching a switching element of an inverter to generate three-phase AC power.

  When a motor torque command is received from an electronic control unit for travel control in inverter control, the motor control system becomes a target by using the motor rotation angle detected by the rotation angle sensor and the motor current detected by the current sensor. A carrier signal for generating motor torque is generated. The motor control system generates a gate signal for turning on and off the switching element of the inverter from the generated carrier signal, and controls the switching element of the inverter. In a motor control system, a resolver having high environmental resistance is used as a rotation angle sensor.

  In Patent Document 1, the resolver / digital converter detects the rotor angle θ based on the sin signal and the cos signal output from the resolver, and the sin signal and the cos signal are each converted into an analog-digital signal at the timing when the peak of the reference signal is detected. An abnormality detection process for estimating the angle θ from the values of the SIN signal and the COS signal is proposed. If the absolute value of the difference between the angle θ detected by the resolver / digital converter and the estimated angle θ exceeds a predetermined abnormality detection threshold, the angle θ detected by the resolver / digital converter is not accurate. Is determined. In Patent Document 1, the peak of the reference signal is detected using a comparator that compares the reference signal with a reference amplitude (peak value).

Japanese Patent Laid-Open No. 9-72758

  In the technique disclosed in Patent Document 1, the dedicated analog / digital converter converts the sin signal and the cos signal output from the resolver into an analog-to-digital converter. Become. The motor control system is equipped with a motor current analog / digital converter for converting the motor current signal into a digital signal every half cycle of the carrier signal. If the cos signal can be used for analog-digital conversion processing, a dedicated analog / digital converter need not be provided separately.

  For the abnormality detection processing of the resolver / digital converter, it is necessary to use the SIN signal value and the COS signal value obtained by converting the sin signal and the cos signal output from the resolver into a digital signal at the peak timing of the reference signal supplied to the resolver. There is. However, since the reference signal and the carrier signal are generated independently from each other, the peak timing of the reference signal may compete with the timing of the half cycle of the carrier signal (that is, the timing of the peak of the peak or valley). If these conflicts, there is a possibility that a problem occurs in the analog-digital conversion processing of any signal. For example, if a problem occurs in the analog-digital conversion processing of the resolver sin signal or cos signal, an incorrect signal value is used. Since the abnormality detection process is executed, there is a problem that it is difficult to accurately detect the abnormality of the resolver / digital converter.

  The present invention has been made in view of such circumstances, and an object of the present invention is to convert a motor current and a resolver when analog-to-digital conversion of a resolver signal (sin signal and cos signal) using an analog / digital converter for motor current. To provide a technique for accurately executing an anomaly detection process of a resolver / digital converter based on a resolver signal value obtained by analog-digital conversion near the peak timing of a reference signal while avoiding a competition with a signal acquisition timing. is there.

  In order to solve the above-described problem, an abnormality detection apparatus for a resolver / digital converter according to an aspect of the present invention includes a reference signal generation unit that generates a reference signal having a predetermined periodic waveform, and a reference signal according to the rotation angle of the motor. A resolver that outputs a sin signal and a cos signal whose amplitude is modulated, a resolver / digital converter that obtains the rotation angle θ of the motor from the sin signal and the cos signal output from the resolver, a motor current signal that flows through the motor, and an output from the resolver An analog / digital converter that converts the sine signal and the cos signal into a digital signal, a motor angle deriving unit that obtains the rotation angle φ of the motor based on the SIN signal value and the COS signal value converted into the digital signal, Time required by resolver / digital converter An abnormality detection unit that compares the rotation angle θ with the rotation angle φ obtained by the motor angle deriving unit and executes an abnormality detection process of the resolver / digital converter. The analog / digital converter converts a motor current signal into a digital signal at a timing at which a motor current value is to be acquired, and converts a sin signal and a cos signal output from the resolver into a digital signal after or before that timing. The abnormality detection unit detects the rotation angle θ and the rotation angle when the sum of the square value of the SIN signal value and the square value of the COS signal value is not less than a predetermined lower limit value and not more than a predetermined upper limit value. Compared with φ, the resolver / digital converter abnormality detection process is executed.

  According to this aspect, since the analog / digital converter for the motor current converts the sin signal and the cos signal output from the resolver into a digital signal, an analog / digital converter for the resolver signal (sin signal, cos signal) is separately provided. There is no need to provide it. When the sum of the square value of the SIN signal value converted into the digital signal and the square value of the COS signal value is not less than a predetermined lower limit value and not more than a predetermined upper limit value, the SIN signal value and the COS value Since it is determined that the signal value is acquired at a timing near the peak of the reference signal, the rotation angle φ of the motor obtained based on the SIN signal value and the COS signal value at this time is obtained by the resolver / digital converter. By comparing with the rotation angle θ of the obtained motor, it is possible to accurately execute the abnormality detection processing of the resolver / digital converter.

  According to the present invention, there is provided a technique for realizing an abnormality detection process of a resolver / digital converter with a simple configuration.

It is a figure which shows the structure of the motor control system in a vehicle provided with electric motors, such as a hybrid vehicle, as a driving source. It is a figure which shows an example of the structure of a resolver. (A) is a REF signal waveform, (b) is a sin signal waveform, and (c) is a diagram showing a cos signal waveform. It is a figure which shows the structure of an inverter control part. It is a figure which shows an example of a carrier signal waveform. It is a figure which shows the flowchart of the RDC abnormality detection process of an Example. It is a figure which shows an example of the relationship between a REF signal, a sin signal, a cos signal, and a carrier signal. It is a figure which shows an example of the relationship between a REF signal and a carrier signal.

  FIG. 1 shows a configuration of a motor control system in a vehicle equipped with an electric motor such as a hybrid vehicle as a travel drive source. The motor control system 1 includes an inverter 2, a boost converter 3, a power source 4, a filter capacitor 5, a motor 10, and a motor electronic control unit 30 (hereinafter referred to as “motor ECU 30”). As a sensor group, the motor control system 1 includes a current sensor 11 that detects a motor current flowing in the V-phase coil of the motor 10, a current sensor 12 that detects a motor current flowing in the W-phase coil of the motor 10, and the rotation of the motor 10. And a resolver 20 for detecting a corner.

  FIG. 2 shows an example of the structure of the resolver 20. The resolver 20 has a stator 21 fixed to a fixed portion of the motor 10 and a rotor 22 fixed to the shaft of the motor 10. The stator 21 is provided with an excitation coil 23 that receives a reference signal (REF signal) having a predetermined periodic waveform, an output coil 24 that outputs a sin signal, and an output coil 25 that outputs a cos signal. The output coil 24 and the output coil 25 are arranged with a phase difference of 90 ° from each other, and the sin signal and the cos signal have a waveform obtained by amplitude-modulating the REF signal according to the rotation angle θ of the rotor 22. As described above, the resolver 20 outputs a sin signal and a cos signal obtained by amplitude-modulating the REF signal according to the rotation angle θ of the motor 10.

  3A shows an example of a REF signal waveform, FIG. 3B shows an example of a sin signal waveform, and FIG. 3C shows an example of a cos signal waveform. When the REF signal is a sine wave (A · sin ωt) (A: amplitude, ω: angular frequency, t: time), the sin signal is expressed by K · A · sin ωt · sin θ, and the cosine signal is K · It is represented by A · sin ωt · cos θ (K: amplitude coefficient). In the following description, it is assumed that A = K = 1 without considering the amplitude of the signal.

  Returning to FIG. 1, the travel control ECU 6 is an electronic control unit for controlling the travel of the vehicle, calculates the motor torque required by the motor 10 in response to the accelerator request and the brake request, and sets the target motor torque to the motor torque. It outputs to motor ECU30 as a command. In the motor control system 1, in accordance with a motor torque command from the travel control ECU 6, the DC power of the power source 4 is boosted and converted to three-phase AC power, and the three-phase AC power is supplied to the motor 10. The motor ECU 30 controls the boost converter 3 to boost the DC voltage of the power source 4 to the target voltage and generates three-phase DC power to the inverter 2 in order to generate torque according to the motor torque command. Inverter control to convert to AC power is performed.

  Filter capacitor 5 is provided between power supply 4 and boost converter 3, and is connected to power supply 4 in parallel. The filter capacitor 5 has a function of smoothing the DC voltage of the power supply 4 and preventing a pulsating current due to switching of the boost converter 3 from flowing to the power supply 4 side.

  Boost converter 3 has a reactor and a switching element, and is connected to power supply 4 through filter capacitor 5. Boost converter 3 includes a current sensor that detects a current flowing through the reactor, and outputs the detected current value to motor ECU 30. The switching element performs a switching operation by a gate signal supplied from the motor ECU 30, and boosts the DC low voltage of the filter capacitor 5 to a DC high voltage.

  The inverter 2 has a smoothing capacitor and a switching element, and is supplied with a boosted DC high voltage. The smoothing capacitor is provided between the switching element of the inverter 2 and the boost converter 3, smoothes the DC voltage boosted by the boost converter 3, and stores the electric charge of the DC voltage. Inverter 2 has a voltage sensor that detects the voltage across the smoothing capacitor, and outputs the detected voltage value to motor ECU 30. The switching element performs a switching operation by a gate signal for each phase (U phase, V phase, W phase) switching element of the motor 10 supplied from the motor ECU 30, converts DC power into three-phase AC power, and converts it to the motor 10. Supply.

  The motor ECU 30 is an electronic control unit that includes a microcomputer, a memory, and the like. The motor ECU 30 includes a boost control unit 32 that controls the boost converter 3 and an inverter control unit 31 that controls the inverter 2. Upon receiving the motor torque command output from the travel control ECU 6, the inverter control unit 31 receives the resolver signal (sin signal, cos signal) detected by the resolver 20 from the motor 10 and the V phase detected by the current sensors 11 and 12. A carrier signal for generating a target motor torque is generated using the motor current signal (Iv signal) and the W-phase motor current signal (Iw signal). For example, if the target vehicle speed is low, the frequency of the carrier signal may be low, and if the target vehicle speed is high, the frequency of the carrier signal may be set high.

  The inverter control unit 31 according to the embodiment has a function of changing the carrier signal in units of half cycles in order to control the motor 10. That is, the inverter control part 31 can set the half cycle of a carrier signal for every half cycle, and controls the motor 10 suitably by this. The inverter control unit 31 generates a gate signal of the switching element of each phase of the inverter 2 using the carrier signal and outputs it to the inverter 2. The inverter 2 switches the switching element of each phase by a gate signal and supplies three-phase AC power to the motor 10.

  The boost control unit 32 calculates the target voltage value when receiving the motor rotation speed and the motor torque command from the inverter control unit 31, and the voltage between both ends of the smoothing capacitor is determined based on the voltage value between both ends of the smoothing capacitor. Control to be a voltage value. Specifically, the boost control unit 32 calculates the target current value of the current flowing through the reactor of the boost converter 3 so that the voltage across the smoothing capacitor becomes the target voltage, and based on the detected current value of the reactor. In addition, the gate signal for the switching element of the boost converter 3 is generated so that the current flowing through the reactor becomes the target current value.

  FIG. 4 shows the configuration of the inverter control unit 31. The inverter control unit 31 includes an analog / digital converter 40 (hereinafter also referred to as “ADC 40”), a resolver / digital converter 41 (hereinafter also referred to as “RDC 41”), a reference signal generation unit 42, a motor control unit 43, and a processing unit 44. And an ADC control unit 47. The inverter control unit 31 according to the embodiment operates as a resolver / digital converter abnormality detection device having a function of detecting abnormality of the RDC 41. The reference signal generator 42 generates a reference signal (REF signal) having a predetermined periodic waveform and supplies it to the exciting coil 23. As a result, the output coil 24 and the output coil 25 output a sin signal and a cos signal corresponding to the rotation angle θ of the motor 10, respectively. The RDC 41 obtains the rotation angle of the rotor 22, that is, the rotation angle θ of the motor 10 from the resolver signal (sin signal and cos signal), and outputs it to the motor control unit 43.

  The ADC 40 is activated and controlled by the ADC controller 47, and the motor current signal (Iv signal) supplied from the current sensor 11, the motor current signal (Iw signal) supplied from the current sensor 12, and the sin supplied from the output coil 24. The cos signal supplied from the signal and output coil 25 is converted into a digital signal.

  The ADC 40 converts the analog Iv signal into a digital IV signal value, converts the analog Iw signal into a digital IW signal value, and outputs the digital IW signal value to the motor control unit 43. The ADC control unit 47 acquires half-cycle information of the carrier signal from the motor control unit 43 and controls the acquisition timing of the motor current signal (Iv signal, Iw signal).

  FIG. 5 shows an example of a carrier signal waveform. The carrier signal is a triangular wave having peaks and valleys as apexes, and can be changed in units of a half cycle. The ADC control unit 47 activates the ADC 40 at the timing of the peak and valley peaks of the carrier signal, that is, the timings of times T0, T1, T2, T3, T4, T5, and T6, and performs analog-to-digital conversion processing of the motor current signal. Run.

  Thereby, the motor control unit 43 generates a carrier signal for generating a target motor torque based on the IV signal value, the IW signal value, and the rotation angle θ acquired every half cycle of the carrier signal, A gate signal is supplied to the inverter 2.

  The ADC 40 converts the analog sin signal into a digital SIN signal value, converts the analog cos signal into a digital COS signal value, and outputs the digital COS signal value to the processing unit 44. The processing unit 44 includes a motor angle deriving unit 45 and an abnormality detection unit 46, and has a function of determining whether the RDC 41 is normal or abnormal.

  The motor angle deriving unit 45 estimates the rotation angle of the motor 10 based on the SIN signal value and the COS signal value acquired at the timing near the peak of the REF signal. Here, in order to distinguish from the rotation angle θ obtained by the RDC 41, the rotation angle estimated by the motor angle deriving unit 45 is expressed as φ. The motor angle deriving unit 45 holds a correspondence table in which sin θ, cos θ, and the rotation angle φ are associated with each other, and by referring to the correspondence table from the SIN signal value and the COS signal value output from the ADC 40, Obtain the rotation angle φ. The abnormality detection unit 46 compares the rotation angle θ obtained by the RDC 41 with the rotation angle φ obtained by the motor angle deriving unit 45, and executes an abnormality detection process of the RDC 41. For example, if the absolute value of the difference between the rotation angle θ and the rotation angle φ exceeds a predetermined abnormality detection threshold, the abnormality detection unit 46 detects that an abnormality has occurred in the RDC 41, and performs a predetermined abnormality. If it is below the detection threshold, it is determined that the RDC 41 is operating normally and the rotation angle θ is accurate. For example, when an abnormality is detected by the abnormality detection unit 46, the motor control unit 43 may take measures such as stopping the drive control of the motor 10.

  As described above, the motor angle deriving unit 45 estimates the rotation angle φ of the motor 10 based on the SIN signal value and the COS signal value acquired at the timing near the peak of the REF signal. Since the cycle of the REF signal and the cycle of the carrier signal are set independently, for example, the peak timing of the REF signal is detected, and the ADC control unit 47 activates the ADC 40 at the detected peak timing, and the resolver signal If an analog-digital conversion process of (sin signal, cos signal) is performed, there is a possibility of competing with the analog-digital conversion process of the motor current signal. When the timing of the analog-digital conversion process competes, at least one of the motor current signal and the resolver signal is not accurately acquired, and the motor control unit 43 or the processing unit 44 performs processing based on an inaccurate value. For example, if the setting is such that the analog-digital conversion processing of the motor current signal is preferentially executed, the analog-digital conversion processing of the resolver signal is not executed or is forcibly terminated midway, and the rotation angle φ It is difficult to accurately obtain

  Therefore, in the RDC abnormality detection device of the embodiment, the ADC control unit 47 does not detect the peak timing of the REF signal and activate the ADC 40 at the detected peak timing. The ADC control unit 47 activates the ADC 40 at a timing at which the motor current value is to be acquired. At this time, the ADC 40 converts the motor current signal into a digital signal, and is output from the resolver 20 after or before that timing. The sin signal and the cos signal are converted into digital signals. For example, the ADC control unit 47 switches input channels to the ADC 40 in the order of the Iv signal, the Iw signal, the sin signal, and the cos signal, and sequentially converts each signal from analog to digital. Note that the ADC control unit 47 may switch the input channel to the ADC 40 in the order of the sin signal, the cos signal, the Iv signal, and the Iw signal. When the ADC 40 completes the conversion process of the four analog signals, the ADC control unit 47 finishes starting the ADC 40 and then starts the ADC 40 at a timing at which the motor current value should be acquired.

  Thereby, ADC40 can convert a motor current signal and a resolver signal into a digital signal value, without the acquisition timing of a motor current signal and a resolver signal overlapping. In the embodiment, the timing at which the motor current value should be acquired is the peak or valley timing of the carrier signal as described with reference to FIG. 5, but may be other timing.

  In the embodiment, the SIN signal value and the COS signal value are acquired regardless of whether or not the peak timing of the REF signal. In order for the motor angle deriving unit 45 to estimate the rotation angle φ, it is necessary to use the SIN signal value and the COS signal value acquired near the peak timing of the REF signal. It is then determined whether the COS signal value is obtained near the peak timing of the REF signal.

This determination is performed by the following equation 1.
Lower limit value ≦ (SIN ² θ + COS ² θ) ≦ Upper limit value (Equation 1)
For example, the predetermined lower limit value may be set to 0.8, and the predetermined upper limit value may be set to 1.2. When the SIN signal value and the COS signal value satisfy Expression 1, it can be seen that the SIN signal value and the COS signal value are values obtained near the peak timing of the REF signal.

  The abnormality detection unit 46 determines the rotation angle θ and the rotation angle φ when the sum of the square value of the SIN signal value and the square value of the COS signal is not less than a predetermined lower limit value and not more than a predetermined upper limit value. And the abnormality detection process of the RDC 41 is executed. When the motor angle deriving unit 45 receives the SIN signal value and the COS signal value regardless of the calculation result of the square sum of the SIN signal value and the COS signal value, the motor angle deriving unit 45 refers to a predetermined correspondence table to determine the rotation angle φ. The rotation angle φ may be obtained when the sum of squares of the SIN signal value and the COS signal satisfies Equation 1.

  As described above, according to the RDC abnormality detection device of the embodiment, one ADC 40 can suitably convert the motor current signal and the resolver signal into a digital signal. Further, the peak of the REF signal described in Patent Document 1 is detected by determining whether or not the acquired SIN signal value and COS signal value are acquired in the vicinity of the peak timing of the REF signal by Equation 1. Therefore, it is possible to realize the abnormality detection processing of the RDC 41 with a simple configuration without requiring a configuration such as a comparator.

  FIG. 6 is a flowchart of the RDC abnormality detection process according to the embodiment. When the ADC control unit 47 starts the ADC 40 at a timing at which the motor current value should be acquired, the ADC 40 converts the motor current signal into a digital signal, and subsequently converts the resolver signal (sin signal, cos signal) into a digital signal. (S10). The ADC 40 may convert the resolver signal into a digital signal, and then convert the motor current signal into a digital signal.

  The motor angle deriving unit 45 calculates the sum of squares of the SIN signal value and the COS signal value converted into a digital signal, and determines whether or not the sum of squares is a predetermined lower limit value or more and a predetermined upper limit value or less. Is determined (S12). When the sum of squares of the SIN signal value and the COS signal value is less than the lower limit value or exceeds the upper limit value (N in S12), the acquired SIN signal value and COS signal value are acquired near the peak timing of the REF signal. Therefore, the abnormality detection process of the RDC 41 is stopped. On the other hand, when the sum of squares of the SIN signal value and the COS signal value is not less than the lower limit value and not more than the upper limit value (Y in S12), the motor angle deriving unit 45 has the SIN signal value and the COS signal value. In addition, the rotation angle φ is derived with reference to a predetermined correspondence table (S14). The abnormality detection unit 46 compares the rotation angle θ obtained by the RDC 41 with the rotation angle φ obtained by the motor angle deriving unit 45, and executes an abnormality detection process of the RDC 41 (S16).

  FIG. 7 shows an example of the relationship between the REF signal, sin signal, cos signal, and carrier signal. As described above, the ADC control unit 47 activates the ADC 40 at the timing of the peak or valley of the carrier signal. Here, the ADC 40 is activated at the timings of times T10, T11, T12, T13, T14, T15, T16, and T17, and analog-digital conversion processing of the motor current signal and the resolver signal is executed.

  As shown in the figure, the period of the carrier signal is changed in units of a half period, and information on the period set by the motor control unit 43 is provided to the ADC control unit 47 and used for starting control of the ADC 40. . In this example, the SIN signal value and the COS signal value acquired at the timings of times T11, T15, and T17 satisfy the condition of Equation 1. Therefore, the motor angle deriving unit 45 derives the rotation angle φ based on the SIN signal value and the COS signal value acquired at the times T11, T15, and T17, and the abnormality detecting unit 46 executes the abnormality detecting process of the RDC 41. To do.

  In the embodiment, when the motor current value and the resolver signal are analog-to-digital converted at the acquisition timing of the motor current value, and the resolver signal is acquired near the peak timing of the REF signal, the processing unit 44 is connected to the RDC 41. Anomaly detection processing is being executed. In the example described with reference to FIG. 7, the abnormality detection process of the RDC 41 is executed at the timings of the times T11, T15, and T17, but the abnormality detection process of the RDC 41 can be executed at a plurality of peak timings of the REF signal. Absent.

  Therefore, in the following modification, the peak timing of the REF signal is detected, and if the detected timing does not conflict with the timing at which the motor current value is to be acquired, the ADC control unit 47 activates the ADC 40 and outputs the resolver signal. Control to convert to digital signal. In the modified example, the REF signal peak timer is used to detect the peak timing. The REF signal peak timer increments the count value in a predetermined cycle, and the count value is reset when the count value reaches the cycle Tref of the REF signal. Then, it operates to increment the count value again. The ADC control unit 47 is provided with the cycle Tref of the REF signal from the reference signal generation unit 42 and operates the REF signal peak timer. If the peak timing of the REF signal does not conflict with the timing for acquiring the motor current value, the ADC 40 And resolver signals (sin signal, cos signal) are converted into digital signals.

  FIG. 8 shows an example of the relationship between the REF signal and the carrier signal. The REF signal has a sinusoidal waveform with a period Tref. The motor control unit 43 receives a motor torque command from the travel control ECU 6 and calculates an optimum half cycle Tf_k of the carrier signal based on the motor current value (IV signal value, IW signal value) and the rotation angle θ. The calculated half-cycle information (Tf_k) is supplied to the ADC control unit 47. In FIG. 8, Tr_i (<Tref) indicates the time acquired by the REF signal peak timer, and τ indicates the time required for the control process by the motor control unit 43 and the control process by the ADC control unit 47. The control process by the ADC control unit 47 includes an ADC activation timing setting process. This setting process determines whether or not the ADC 40 can be activated in order to acquire the resolver signal at the peak timing of the REF signal. Includes a process of setting the activation time.

  At time T20, the ADC control unit 47 activates the ADC 40 and converts the motor current signal (Iv signal, Iw signal) into a digital signal (IV signal value, IW signal value). In the embodiment, the ADC 40 converts the resolver signal (sin signal, cos signal) into a digital signal at the timing before and after this. However, in this modification, the resolver signal may not be converted into a digital signal.

  The ADC control unit 47 acquires the REF signal peak timer value (Tr_1) after the time τ of the time T20 in the setting process of the ADC activation timing, and sets the time until the peak timing of the next REF signal as (Tref−Tr_1). calculate. Tr_1 is obtained by adding time τ to the REF signal peak timer value at time T20. Further, the ADC control unit 47 acquires the half cycle (Tf_1) of the carrier signal from the motor control unit 43, and then starts the ADC 40 for acquiring the motor current value from the time τ after the time T20, That is, the time until the time T22 when the carrier signal becomes a valley is calculated as (Tf_1−τ).

Here, the ADC control unit 47
Tref-Tr_1 <Tf_1-τ
Whether or not is satisfied is determined. In this equation, the left side represents the time until the peak timing of the next REF signal, and the right side represents the time until the ADC 40 is activated to acquire the motor current value. It means that the peak timing of the REF signal arrives before starting the ADC 40 for value acquisition. Accordingly, at this time, even if the ADC 40 is activated to obtain the resolver signal, no contention occurs. Therefore, at time T21, the ADC control unit 47 activates the ADC 40 and converts the resolver signal into a digital signal. The SIN signal value and the COS signal value acquired at this time are used by the motor angle deriving unit 45 to derive the rotation angle φ.

  Next, at time T22, the ADC control unit 47 activates the ADC 40 and converts the motor current signal into a digital signal. The ADC control unit 47 acquires the REF signal peak timer value (Tr_2) after the time τ of the time T22, and calculates the time until the peak timing of the next REF signal as (Tref−Tr_2). Also, the ADC control unit 47 acquires the half cycle (Tf_2) of the carrier signal from the motor control unit 43, and then starts the ADC 40 for acquiring the motor current value from the time τ after the time T22, That is, the time until the time T24 when the carrier signal becomes a peak is calculated as (Tf_2−τ).

here,
Tref-Tr_2 <Tf_2-τ
Therefore, the ADC control unit 47 activates the ADC 40 at time T23 to convert the resolver signal into a digital signal. The SIN signal value and the COS signal value acquired at this time are used by the motor angle deriving unit 45 to derive the rotation angle φ.

  Next, at time T24, the ADC control unit 47 activates the ADC 40 to convert the motor current signal into a digital signal. The ADC control unit 47 acquires the REF signal peak timer value (Tr_3) after the time τ of the time T24, and calculates the time until the peak timing of the next REF signal as (Tref−Tr_3). Also, the ADC control unit 47 acquires the half cycle (Tf_3) of the carrier signal from the motor control unit 43, and then starts the ADC 40 for acquiring the motor current value from the time τ after the time T24, That is, the time until the time T25 when the carrier signal becomes a valley is calculated as (Tf_3-τ).

here,
Tref-Tr_3 <Tf_3-τ
This inequality is not established, and the magnitude relationship of Tref−Tr — 3> Tf — 3−τ is detected. In this case, when the ADC 40 is activated at time T26, the ADC control unit 47 determines that there is a possibility that a motor current signal or a resolver signal may not be accurately acquired due to a conflict. Therefore, the ADC control unit 47 does not start the ADC 40 at time T26 in order to acquire the resolver signal. On the other hand, the ADC 40 that starts at time T25 acquires not only the motor current signal but also the resolver signal. , ADC 40 is controlled. That is, the ADC 40 is activated at time T25 and converts not only the motor current signal but also the resolver signal into a digital signal. As described with reference to FIG. 6, the SIN signal value and the COS signal value acquired in this way are determined by Equation 1 as to whether or not their sum of squares is within a range determined by a predetermined lower limit value and upper limit value. Is determined. When the sum of squares is equal to or greater than the lower limit value and equal to or less than the upper limit value, the motor angle deriving unit 45 obtains the rotation angle φ with reference to the correspondence table, and the abnormality detection unit 46 determines the rotation angle θ and the rotation angle. The abnormality detection process of the RDC 41 is executed by comparing with φ.

  The ADC control unit 47 may control the ADC 40 activated at time T25 so as to acquire a resolver signal, and may instruct the motor angle deriving unit 45 to perform a square sum determination process. Upon receiving this instruction, the motor angle deriving unit 45 can determine whether or not the abnormality detection process using the SIN signal value and the COS signal value acquired at time T25 can be executed. On the other hand, for the SIN signal value and the COS signal value acquired at the peak timing (T21, T23) of the REF signal, the motor angle deriving unit 45 refers to the correspondence table without performing the square sum determination process. May be used to determine the rotation angle φ.

  In the modified example, in order to acquire the resolver signal by comparing the magnitude relationship between the time until the peak timing of the next REF signal and the time until the timing of starting the ADC 40 next for acquiring the motor current value It has been described that it is determined whether the ADC 40 can be activated. When the half cycle of the carrier signal is larger than twice the cycle Tref of the REF signal, the time until the next activation timing of the ADC 40 for obtaining the motor current value and the timing at which the ADC 40 is activated. Compared with the time until the peak timing of the plurality of REF signals arriving at, the ADC control unit 47 may determine whether or not the ADC 40 can be activated to obtain the resolver signal.

  In order to determine whether or not the ADC 40 can be activated, the magnitude relationship between the time until the peak timing of the next REF signal and the time until the timing when the ADC 40 is activated next for obtaining the motor current value is compared. Another criterion may be adopted.

  In the above, this invention was demonstrated based on the Example and the modification. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Motor control system, 2 ... Inverter, 3 ... Boost converter, 4 ... Power supply, 5 ... Filter capacitor, 6 ... Travel control ECU, 10 ... Motor, 11, DESCRIPTION OF SYMBOLS 12 ... Current sensor, 20 ... Resolver, 21 ... Stator, 22 ... Rotor, 23 ... Excitation coil, 24, 25 ... Output coil, 30 ... Motor ECU, 31. ..Inverter controller, 32... Boost controller, 40... ADC, 41... RDC, 42... Reference signal generator, 43. 45 ... Motor angle deriving unit, 46 ... Abnormality detecting unit, 47 ... ADC control unit.

Claims (1)

A reference signal generator for generating a reference signal having a predetermined periodic waveform;
A resolver that outputs a sin signal and a cosine signal obtained by amplitude-modulating the reference signal according to a rotation angle of the motor;
A resolver / digital converter for obtaining a rotation angle θ of the motor from a sin signal and a cos signal output from the resolver;
An analog / digital converter that converts a motor current signal flowing through the motor, a sin signal and a cos signal output from the resolver into a digital signal;
A motor angle deriving unit for obtaining a rotation angle φ of the motor based on the SIN signal value and the COS signal value converted into a digital signal;
An abnormality detection unit that compares the rotation angle θ obtained by the resolver / digital converter with the rotation angle φ obtained by the motor angle deriving unit, and executes an abnormality detection process of the resolver / digital converter, An anomaly detection device for a resolver / digital converter,
The analog / digital converter converts the motor current signal into a digital signal at a timing at which a motor current value is to be obtained, and also outputs a sin signal and a cos signal output from the resolver as a digital signal after or before that timing. Converted to
When the sum of the square value of the SIN signal value and the square value of the COS signal value is greater than or equal to a predetermined lower limit value and less than or equal to a predetermined upper limit value, the abnormality detection unit Comparing with the rotation angle φ, the abnormality detection processing of the resolver / digital converter is executed.
An anomaly detection device for a resolver / digital converter.

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