Motor control device and program

Abstract

To provide a motor control device and a program capable of giving desired torque to a load of a motor.SOLUTION: A motor control device according to the present disclosure controls voltage signals of multiple phases to be applied to an AC motor. The motor control device includes: a differential value calculation unit that calculates a time differential value on a virtual line connecting peak values of phase voltage signals which are voltage signals of the respective phases to be inputted to the AC motor; a wavelength calculation unit that calculates wavelengths of the respective phase voltage signals to be inputted to the AC motor on the basis of the time differential value; and a switch signal generation unit that generates a signal for switching a phase of the AC motor to which AC voltage is to be applied on the basis of the calculated wavelengths.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a motor control device and a program. [Background technology]

[0002] When a motor is driven at a constant rotation speed with sensorless energization, if the motor load suddenly changes, a discrepancy may occur between the control system's prediction of the motor's rotation period and the actual motor rotation period.If the discrepancy between the control system's prediction of the motor's rotation period and the actual motor rotation period becomes large, torque cannot be obtained, leading to step-out. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-149900 A Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above-mentioned problems, the present disclosure has an object to provide a motor control device and a program capable of applying a desired torque to a motor load. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems and achieve the object, a motor control device according to the present disclosure includes: A motor control device for controlling an AC motor, comprising: an analog-to-digital conversion unit that generates phase voltage signals, which are voltages of each phase of the AC motor, by acquiring and analog-to-digital-converting a voltage in wiring connecting the inverter and the AC motor; and a voltage value of each phase voltage signal at any timing between a first timing at which a voltage value of each phase voltage signal rises or falls and a second timing at which the voltage value of each phase voltage signal rises or falls after the first timing, as a peak value of each phase voltage signal; a differential value calculation unit that calculates a time differential value on a virtual line connecting the peak values ​​of each phase voltage signal; The rotation waveform of the AC motor, which is the reciprocal of the period of one rotation of the AC motor, The optical fiber includes a wavelength calculation unit that calculates a wavelength, and a switching signal generation unit that generates a signal for switching the phase of the AC motor based on the calculated wavelength.

[0006] In order to solve the above problems and achieve the object, the program according to the present disclosure includes: A program for causing a computer to execute control of an AC motor, the program comprising the steps of: applying a voltage to the AC motor from an inverter in a 120° energization method; acquiring a voltage in wiring connecting the inverter and the AC motor and performing analog-to-digital conversion to generate phase voltage signals which are voltages of each phase of the AC motor; acquiring, as peak values ​​of the phase voltage signals, voltage values ​​of the phase voltage signals at any timing between a first timing at which a voltage value of the phase voltage signals rises or falls and a second timing at which the voltage value of the phase voltage signals rises or falls after the first timing;calculating a time differential value on a virtual line connecting the peak values ​​of the phase voltage signals; A rotation waveform of the AC motor, which is the reciprocal of the period of one rotation of the AC motor. and generating a signal for switching the phase of the AC motor based on the calculated wavelength. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a motor control device and a program capable of preventing loss of synchronism even in the event of a sudden load change, thereby providing a desired torque to a motor load. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration example of a motor system according to the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating a schematic configuration example of the control device according to the first embodiment. [Diagram 3] FIG. 3 is a diagram showing changes in each phase voltage signal over time. [Figure 4] FIG. 4 is a diagram showing an example of virtual lines connecting the peak values ​​of the phase voltage signals. [Diagram 5] FIG. 5 is a diagram showing an example of peak values ​​of each phase voltage signal. [Figure 6] FIG. 6 is a diagram showing changes over time in the time differential values ​​of the phase voltage signals. [Figure 7] FIG. 7 is a diagram showing a correction signal. [Figure 8] FIG. 8 is a diagram showing the signals after the absolute values ​​of the correction signals for each phase have been calculated. [Figure 9] FIG. 9 is a diagram showing a total signal obtained by combining all the signals after the absolute values ​​of the respective phases are calculated. [Figure 10] FIG. 10 is a diagram showing a sample-and-hold signal obtained by sampling and holding the total signal. [Figure 11] FIG. 11 is a flowchart illustrating a control method according to the present disclosure. [Figure 12]FIG. 12 is a diagram showing a result of signal processing by the control device according to the second embodiment. [Figure 13] FIG. 13 is a diagram showing a result of signal processing by the control device according to the third embodiment. [Figure 14] FIG. 14 is a diagram showing each phase voltage signal acquired by an analog-to-digital converter of the control device according to the fourth embodiment. [Figure 15] FIG. 15 is a diagram showing an example of virtual lines connecting peak values ​​of each phase voltage signal in the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below.

[0010] (First embodiment) (Motor system configuration) Fig. 1 is a diagram showing a schematic configuration example of a motor system according to the present disclosure. As shown in Fig. 1, the motor system 100 according to the present disclosure includes an AC motor 10, an inverter 20, a positive power supply 30, a control device 40, and a drive circuit 50.

[0011] The AC motor 10 converts electrical energy into mechanical work. The AC motor 10 includes, for example, a stator and a rotor. The stator is a fixed part of the motor. The stator includes three coils arranged at 120° phases. The three coils are called U-phase coil, V-phase coil, and W-phase coil. The coils may be connected by either δ-connection or Y-connection. The rotor is a rotating part of the motor. The AC motor 10 generates a magnetic field by applying an AC voltage to the coils of the stator, and rotates the rotor by interaction with the magnetic force of the permanent magnet of the rotor. By using three-phase AC, a rotating magnetic field can be easily obtained. A predetermined load is connected to the output shaft of the rotor of the AC motor 10, and mechanical work is performed on the load by the rotation of the rotor of the AC motor 10. In this manner, the AC motor 10 may convert electrical energy into mechanical work.

[0012] The inverter 20 converts a DC voltage supplied from a positive power supply 30 into an AC voltage and supplies it to the AC motor 10. The inverter 20 includes an inverter circuit that applies an AC voltage to a coil of each phase of the AC motor 10. The inverter circuit includes semiconductor switching elements connected to the coil of each phase of the AC motor 10. That is, the inverter circuit of the inverter 20 has a wiring that connects the positive power supply 30 and the U-phase coil of the AC motor 10 and is provided with a semiconductor switching element, a wiring that connects the positive power supply 30 and the V-phase coil of the AC motor 10 and is provided with a semiconductor switching element, and a wiring that connects the positive power supply 30 and the W-phase coil of the AC motor 10 and is provided with a semiconductor switching element, all of which are connected in parallel to the positive power supply 30.

[0013] The semiconductor switching element may be, for example, a bipolar transistor. Alternatively, the semiconductor switching element may be a gate turn-off thyristor (GTO), an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), a silicon carbide metal-oxide-semiconductor field-effect transistor (SiC-MOSFET), a gallium nitride field-effect transistor (GaN-FET), a power semiconductor using gallium oxide (Ga2O3), or the like.

[0014] The inverter 20 supplies AC voltage to each phase coil of the AC motor 10 by periodically turning the semiconductor switching elements ON / OFF, i.e., switching, when a drive signal is provided to the gates of the semiconductor switching elements from a drive circuit 50 described later.

[0015] The positive power supply 30 is a power supply that supplies a DC voltage to the inverter 20. The positive power supply 30 may be a battery or a DC power supply. Furthermore, when the positive power supply 30 generates a DC voltage from an AC power supply, it may include a rectifier circuit, a transformer, a smoothing capacitor, and the like.

[0016] (Configuration of the control device (motor control device)) The control device (motor control device) 40 generates a control signal for controlling the AC motor 10. First, the control device 40 includes a control unit 41 and a storage unit 42, as shown in FIG.

[0017] The control unit 41 is realized by a CPU (Central Processing Unit), MPU (Micro Processing Unit), etc., executing various programs stored in the storage unit 42 using a RAM (Random Access Memory) as a working area. The control unit 41 may also be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), an analog circuit using an operational amplifier, etc.

[0018] Next, the configuration of the control unit 41 will be described with reference to Fig. 2. Fig. 2 is a diagram illustrating a schematic configuration example of the control unit according to the present disclosure. As shown in Fig. 2, the control unit 41 includes an analog-to-digital conversion unit 411, a signal processing unit 412, an unnecessary signal removal unit 413, an absolute value calculation unit 414, a merging unit 415, a sample-and-hold unit 416, a wavelength calculation unit 417, and a switching signal generation unit 418.

[0019] The analog-to-digital converter 411 converts the AC motor 10 and the inverter 20. The AC voltages (U-phase voltage, V-phase voltage, and W-phase voltage) are acquired, and the acquired AC voltages are converted from analog to digital to obtain the voltage signals for each phase. and the inverter 20. The voltage signals are obtained by analog-to-digital conversion of the AC voltages of the respective phases (U phase, V phase, and W phase in this example). In this embodiment, the voltage signals of the respective phases are signals having a waveform in which the voltage value repeatedly rises and falls with respect to a predetermined voltage value as a reference. The analog-to-digital conversion unit 411 converts the analog-to-digital converted voltage signals of the respective phases (AD U , A.D. V , A.D. W The analog-to-digital converter 411 outputs the AC motor 10 and the inverter 20. The AC voltage may be taken with respect to ground.

[0020] FIG. 3 is a diagram showing the time change of each phase voltage signal. As shown in FIG. 3, from the moment when an AC voltage is applied to each phase coil of the AC motor 10, the peak value of each phase voltage signal gradually increases with a predetermined gradient for a predetermined time. After that, each phase voltage signal having a peak value equal to the voltage value applied by the positive power supply 30 is repeated for a predetermined time. When the logic output is turned off, the peak value of each phase voltage signal gradually decreases with a predetermined gradient. The analog-to-digital conversion unit 411 acquires such analog each phase voltage signal and converts the analog each phase voltage signal into a digital each phase voltage signal. If the voltage signal during the period from when the voltage signal value rises to when it falls is defined as one cycle of the voltage signal, the peak value of the voltage signal refers to the maximum voltage value in one cycle of the voltage signal.

[0021] The analog-to-digital conversion unit 411 may be of a flash type or successive approximation type that converts an analog signal into a digital signal using a circuit that compares an input voltage with a reference voltage and outputs whether the voltage is higher or lower than the reference.

[0022] The signal processing unit 412 processes the analog-to-digital converted voltage signals of each phase of the AC motor 10. The signal processing unit 412 includes an intermediate voltage value detection unit 4121 and a differential value calculation unit 4122.

[0023] The intermediate voltage value detection unit 4121 detects the intermediate voltage value of each phase voltage signal from each phase voltage signal of the AC motor 10. More specifically, the intermediate voltage value detection unit 4121 detects the timing at which the signal value of each phase voltage signal becomes the intermediate voltage value from each phase voltage signal. Here, the intermediate voltage value refers to a voltage value between the lower limit value and the upper limit value that the voltage value of each phase voltage signal can take. The intermediate voltage value may be any value between the lower limit value and the upper limit value that the voltage value can take, but is preferably the median value between the lower limit value and the upper limit value. That is, for example, when the lower limit value is 0V and the upper limit value is 12V, the intermediate voltage value is preferably 6V, which is set as the starting point of wavelength utilization. For example, the point where the voltage exceeds 6V as the starting point can be set as the switching timing at a point 30° ahead in electrical angle. Note that the angle is not limited to 30° and can be appropriately changed according to the rotation speed of the AC motor 10.

[0024] The differential value calculation unit 4122 calculates a time differential value of a virtual line L connecting the peak values ​​P of the voltage signals of the phases of the AC motor 10, which will be described later. The differential value calculation unit 4122 calculates a time differential value (N 01U ,N 01W ,N 01V 3, the peak value of each phase voltage signal of AC motor 10 increases with a predetermined slope for a predetermined time from the moment the logic output is turned on, and the peak value decreases with a predetermined slope for a predetermined time from the moment the logic output is turned off.

[0025] 4 is a diagram showing an example of a virtual line connecting the peak values ​​of each phase voltage signal. The differential value calculation unit 4122 detects the peak value P of each phase voltage signal of the AC motor 10 for each time from each phase voltage signal of the AC motor 10. Then, the differential value calculation unit 4122 calculates a time differential value of a virtual line L connecting the peak values ​​P for each time based on the peak value P for each phase voltage signal. That is, for example, the differential value calculation unit 4122 detects the peak value P of the U-phase voltage signal for each time from the U-phase voltage signal, and differentiates the virtual line L connecting the peak values ​​P for each time with respect to time based on the peak value P of the U-phase voltage signal for each time to calculate the time differential value of the virtual line L connecting the peak values ​​P of the U-phase voltage signal.

[0026] In this embodiment, the peak value P of the voltage signal is a voltage signal value for each time that is outside the range of a predetermined threshold TH, which will be described later. In other words, the voltage signal value in each cycle of the voltage signal is outside the range of the threshold TH. In this embodiment, as shown in FIG. 4, the waveform of each phase voltage signal is a cycle in which the voltage signal value is maintained at a reference value (0V in this example) within the range of the predetermined threshold TH for a predetermined period, the voltage signal value then changes to a value outside the range of the predetermined threshold TH (a voltage value higher than the predetermined threshold TH in this example), the voltage signal value is maintained outside the range of the predetermined threshold TH for a predetermined period, and then the voltage signal value returns to the reference value within the range of the predetermined threshold TH. In other words, the waveform of each phase voltage signal is a cycle waveform in which a time period in which the voltage signal value is maintained within the range of the predetermined threshold TH and a time period in which the voltage signal value is maintained outside the predetermined range are alternately repeated. Therefore, as shown in FIG. 4, the peak value P of the voltage signal refers to the voltage signal value in a time period in which the voltage signal value is maintained outside the range of the predetermined threshold TH. Moreover, since the time period during which the voltage signal value is maintained outside the range of the predetermined threshold TH is repeated through the time period during which the voltage signal value is maintained within the range of the predetermined threshold TH, the virtual line L connecting the peak values ​​P can be said to be a line connecting the voltage values ​​(peak values ​​P) in each time period during which the voltage signal value is maintained outside the range of the predetermined threshold TH, as shown in Fig. 4. Note that the predetermined threshold TH here may be set arbitrarily. For example, in this embodiment, since the voltage signal value varies from ground to the positive power supply voltage Vcc (0V to 12V in this example), it may be determined that the voltage signal value is outside the range of the predetermined threshold TH when it is higher than 0V.

[0027] FIG. 5 is a diagram showing an example of the peak value of each phase voltage signal. As described above, the peak value P of the voltage signal refers to the voltage signal value in the time period in which the voltage signal value is maintained outside the range of the predetermined threshold TH. Here, as shown in FIG. 5, the timing at which the voltage signal value changes from within the range of the predetermined threshold TH to outside the range of the predetermined threshold TH (in this example, a voltage value higher than the predetermined threshold TH) is defined as the first timing t1, and the timing at which the voltage signal value returns to within the range of the predetermined threshold TH after the first timing t1 is defined as the second timing t2. The first timing t1 can also be said to be the timing at which the voltage signal value detected immediately before is within the predetermined range, and the voltage signal value detected at the first timing t1 is outside the predetermined range. Similarly, the second timing t2 can also be said to be the timing at which the voltage signal value detected at the second timing t2 is outside the predetermined range, and the voltage signal value detected immediately thereafter is within the predetermined range. In this example, the voltage signal is a PWM waveform in which the voltage value repeatedly rises and falls with respect to 0V, so the timing when the voltage value rises from 0V is the first timing t1, and the timing when the voltage value falls to 0V is the second timing t2. As shown in Fig. 5, in the time period from the first timing t1 to the second timing t2, the voltage signal value is maintained outside the range of a predetermined threshold value TH. In this case, the differential value calculation unit 4122 may treat the voltage signal value at any timing from the first timing t1 to the second timing t2 as the peak value P in one time period in which the voltage signal value is maintained outside the range of the predetermined threshold value TH.

[0028] The differential value calculation unit 4122 may acquire the peak value P of each phase voltage signal by any method based on the voltage signal of each phase. For example, the differential value calculation unit 4122 may sequentially acquire the voltage signal, determine whether the acquired voltage signal value is within a range of a predetermined threshold value TH, and acquire the voltage signal value outside the range of the threshold value TH as the peak value P. However, it is not essential to determine whether the voltage signal value is outside the range of the threshold value TH. For example, since the control unit 41 knows the output timing of the PWM signal, the differential value calculation unit 4122 may acquire the timing at which the voltage signal value becomes the peak value P, which is recognized based on the output timing of the PWM signal, and acquire the voltage signal value at that timing as the peak value P. Note that, when the process of acquiring the peak value P based on the threshold value TH is performed, the threshold value TH can be set arbitrarily, so that, for example, by setting the threshold value TH higher than a reference voltage (0 V in this example) in consideration of noise, erroneous detection of the peak value P due to noise can be suppressed.

[0029] As described above, the differential value calculation unit 4122 may treat the voltage signal value at any timing between the first timing t1 and the second timing t2 as the peak value P. For example, the differential value calculation unit 4122 may treat the voltage signal value P1 at the first timing t1 as the peak value P, may treat the voltage signal value P2 at the second timing t2 as the peak value P, or may treat the voltage signal value P3 at the midpoint timing t3 as the peak value P. That is, the differential value calculation unit 4122 may treat the voltage signal value P1 at the first timing t1, the voltage signal value P2 at the second timing t2, or the voltage signal value P3 at the midpoint timing t3 as the peak value P in one time period in which the voltage signal value is maintained outside the range of the predetermined threshold value TH. Note that the midpoint timing t3 is the timing that is the midpoint between the first timing t1 and the second timing t2. In other words, the midpoint timing t3 is a timing between the first timing t1 and the second timing t2, and refers to the timing when the time from the first timing t1 to the midpoint timing t3 is equal to the time from the midpoint timing t3 to the second timing t2.

[0030] The time waveform of the voltage signal value in the time period from the first timing t1 to the second timing t2 in which the voltage signal value is maintained outside the range of the predetermined threshold TH may be any. For example, as shown in (A) of FIG. 5, the voltage signal value may be constant from the first timing t1 to the second timing t2. For example, as shown in (B) of FIG. 5, the voltage signal value may gradually increase from the first timing t1 to the second timing t2, as shown in (C) of FIG. 5, the voltage signal value may gradually decrease from the first timing t1 to the second timing t2, as shown in (D) of FIG. 5, the voltage signal value may gradually increase from the first timing t1 to the midpoint timing t3 and gradually decrease from the midpoint timing t3 to the second timing t2. Note that even in the waveforms shown in (B) and (D) of FIG. 5, the timing at which the voltage signal value first falls outside the range of the threshold TH (becomes larger than the threshold TH) in one cycle is the first timing t1, so the timing at which the voltage signal value rises is the first timing t1. In either case of the waveform, the differential value calculation unit 4122 may treat the voltage signal value at any timing between the first timing t1 and the second timing t2 as the peak value P. However, it is preferable that the differential value calculation unit 4122 treats the voltage signal value P3 at the midpoint timing t3 as the peak value P. For example, in the case of a waveform having edges at the rising and falling edges as shown in (B) and (C) of FIG. 5, if the voltage signal value P1 at the first timing t1 of the rising edge is set as the peak value P, the difference between the voltage signal value P1 set as the peak value P and the voltage signal value P2 at the second timing t2 of the falling edge becomes large, and the actual peak value P may not be detected with high accuracy due to the influence of the edge. Similarly, in the case of a waveform as shown in (B) and (C) of FIG. 5, if the voltage signal value P2 at the second timing t2 of the falling edge is set as the peak value P, the difference between the voltage signal value P2 set as the peak value P and the voltage signal value P1 at the first timing t1 of the rising edge becomes large, and the actual peak value P may not be detected with high accuracy due to the influence of the edge. In contrast, by setting the voltage signal value P3 at the midpoint timing t3 as the peak value P, the effect of edges is reduced, and the actual peak value P can be detected with high accuracy.Also, even in the case of a waveform such as that shown in FIG. 5D, by taking the voltage signal value P3 at the midpoint timing t3 as the peak value P, the actual peak value P can be detected with high accuracy.

[0031] The differential value calculation unit 4122 may calculate the time differential value of the virtual line L connecting the peak values ​​P for each time in the phase by any method using the peak values ​​P for each time of the voltage signal. For example, the differential value calculation unit 4122 may calculate the time differential value of the virtual line L connecting the peak values ​​P based on the peak value P at the timing to be calculated and the peak value P at the timing immediately before the timing. In this case, for example, the differential value calculation unit 4122 may calculate the value obtained by subtracting the peak value P at the timing to be calculated from the peak value P at the timing immediately before the calculation, divided by the time between those timings, as the time differential value at the timing to be calculated. That is, in this case, the value obtained by subtracting the peak value P at the timing immediately before the calculation from the peak value P at the timing to be calculated and dividing the value by the time between those timings corresponds to the slope of the virtual line L connecting the peak value P at the timing to be calculated and the peak value P at the timing immediately before the calculation, and therefore can be said to be the time differential value of the virtual line L. In addition, during a period during which the voltage signal value does not fall outside the range of a predetermined threshold value TH (for example, period T shown in Figure 4), a reference value within the range of the predetermined threshold value TH (0 V in this example) may be treated as the peak value P for that period, as shown in Figure 4, to calculate the time differential value of the virtual line L.

[0032] FIG. 6 is a diagram showing a change over time in the time differential value of each phase voltage signal. The differential value calculation unit 4122 calculates the time differential value of the virtual line L connecting the peak values ​​P of each phase voltage signal for each time (for each timing). When the time differential value of the virtual line L connecting the peak values ​​P of each phase voltage signal for each time is plotted on the time axis, the time waveform of the time differential value becomes, for example, as shown in FIG. 6. As shown in FIG. 6, the time differential value of each phase voltage signal is kept constant while the peak value of each phase voltage signal increases with a predetermined gradient for a predetermined time. In addition, the time differential value of each phase voltage signal is kept constant even while the peak value of each phase voltage signal decreases with a predetermined gradient for a predetermined time.

[0033] In the present embodiment, as described above, the detection of the peak value P and the calculation of the time differential value are performed using the voltage signal digitally converted by the analog-digital conversion unit 411. However, it is not essential to use the digitally converted voltage signal. For example, the analog value of the voltage signal of each phase of the AC motor 10 may be detected, and the peak value P of the voltage signal may be detected from the analog value of the detected voltage signal. In this case, for example, the analog value of the fluctuating voltage signal is held at a constant value by sample-holding at a predetermined timing. The differential value calculation unit 4122 detects the held analog value of the voltage signal as the peak value P. Then, based on the peak value P of the voltage signal for each time detected by holding the analog value, the differential value calculation unit 4122 calculates the time differential value of the virtual line L connecting the peak values ​​P in the same manner as described above. That is, for example, the differential value calculation unit 4122 may calculate the value obtained by subtracting the peak value P at the timing to be calculated from the peak value P at the timing immediately before the timing, and dividing the result by the time between the timings, as the time differential value at the timing to be calculated. In this case, the value obtained by subtracting the peak value P at the timing to be calculated from the peak value P at the immediately preceding timing and dividing the value by the value between those timings corresponds to the slope of the virtual line L connecting the peak value P at the timing to be calculated and the peak value P at the immediately preceding timing, and can therefore be said to be the time differential value of the virtual line L.

[0034] The unnecessary signal removal unit 413 removes unnecessary signals in the time differential value of the virtual line L connecting the peak values ​​P of the phase voltage signals at each time and outputs a corrected signal (N 02U ,N 02W ,N 02V ) is output. Here, the unnecessary signal means a signal in which the time differential value of the virtual line L connecting the peak values ​​P of the voltage signals of the phases of the AC motor 10 is kept constant for a period not exceeding a predetermined time. That is, the correction signal is a signal obtained after removing the unnecessary signal from the signal indicating the time differential value of the virtual line L connecting the peak values ​​P of the voltage signals of the phases at each time. In other words, the correction signal is a signal having a time waveform obtained by removing (setting to zero) the time waveform of the time differential value of the virtual line L (i.e., the correction signal) in the time period in which the time differential value is kept constant for a period not exceeding a predetermined time. As shown in FIG. 6, there may be a plurality of unnecessary signals (areas surrounded by dashed circles in FIG. 6) in which the time differential value of the virtual line L connecting the peak values ​​P of the voltage signals of the phases is kept constant for a period not exceeding a predetermined time. The unnecessary signal removal unit 413 removes such unnecessary signals by filtering or masking them for a certain period of time after the current is applied.

[0035] Fig. 7 is a diagram showing the correction signal. As shown in Fig. 7, after removing the unnecessary signal from the time differential value of the virtual line L connecting the peak values ​​P of the voltage signals of the phases at each time, a signal remains in which the time differential value of the virtual line L connecting the peak values ​​P of the voltage signals of the phases of the AC motor 10 is kept constant for a predetermined time, and the unnecessary signal remover 413 uses this signal as the correction signal.

[0036] The absolute value calculation unit 414 calculates the absolute value of the correction signal for each phase for each phase. That is, if a negative signal remains in the correction signal for each phase after removing the unnecessary signal, the absolute value calculation unit 414 executes a process of converting the negative signal into a positive signal. The absolute value calculation unit 414 calculates the absolute value of the correction signal for each phase (N 03U ,N 03W ,N 03V ) is output.

[0037] Fig. 8 is a diagram showing the correction signal for each phase after the absolute value is calculated. As shown in Fig. 8, after the absolute value calculation process is performed, there are no negative signals in the correction signal for each phase, and only positive signals or signals whose value is zero remain.

[0038] The merger unit 415 merges the signals included in the correction signals of each phase to generate a total signal (N 04all The merger unit 415 calculates a total signal (N 04all ) is output. The merging unit 415 also calculates a total signal by merging the absolute values ​​of the correction signals of the respective phases. That is, the merging unit 415 executes a process of merging all of the U-phase, V-phase, and W-phase signals after the absolute value calculation process is executed. In other words, the merging unit 415 adds up the correction signals of the respective phases after the absolute value calculation process for each time, thereby calculating a total signal in which the absolute values ​​of the correction signals of the respective phases for each time are superimposed on the same time axis.

[0039] 9 is a diagram showing a total signal obtained by summing all the signals after the absolute values ​​of each phase are calculated. As shown in FIG 9, after the process of summing all the signals after the absolute values ​​of each phase are calculated, a signal is generated by summing all the signals of the U phase, V phase, and W phase.

[0040] The sample and hold unit 416 generates a sample and hold signal (N 05all The sample-and-hold unit 416 calculates a sample-and-hold signal (N 05all ) is output. That is, the sample and hold unit 416 holds a value other than zero for the total signal obtained after the merge unit 415 sums up the absolute values ​​of all the phase signals, and executes a process of keeping the total signal at a constant value until the absolute value of each phase signal changes to a value other than zero. In other words, the sample and hold signal is a signal obtained by correcting the total signal so that the value of the total signal in a time period when the value of the total signal is zero becomes the value of the total signal immediately before that time period.

[0041] 10 is a diagram showing a sample-and-hold signal obtained by sampling and holding the sum signal. As shown in FIG 10, after the sample-and-hold process is executed, there is no period during which the signal value is held at zero.

[0042] The wavelength calculation unit 417 calculates the wavelength of each phase voltage signal input to the AC motor 10 based on a time differential value of a virtual line L connecting peak values ​​P of each phase voltage signal of the AC motor 10. The wavelength calculation unit 417 includes a first wavelength calculation unit 4171, a second wavelength calculation unit 4172, and a third wavelength calculation unit 4173.

[0043] The first wavelength calculation unit 4171 calculates the wavelength of each phase voltage signal input to the AC motor 10 from the time differential value. Specifically, the first wavelength calculation unit 4171 calculates the wavelength of each phase voltage signal input to the AC motor 10 from the sample-and-hold signal. That is, the first wavelength calculation unit 4171 obtains the wavelength of each phase voltage signal input to the AC motor 10 by taking the reciprocal of the value of the sample-and-hold signal and multiplying the value obtained by taking the reciprocal by a proportionality coefficient. The proportionality coefficient can be obtained by a constant specific to the AC motor 10. The first wavelength calculation unit 4171 may also calculate a moving average of the calculated wavelength. For example, in this case, the first wavelength calculation unit 4171 may calculate a moving average (for example, a simple moving average) of the wavelength calculated this time and the wavelengths calculated so far, and use the calculated moving average as the wavelength calculated this time. This makes it possible to suppress fluctuations in the wavelength output by the first wavelength calculation unit 4171 even when the fluctuations are large.

[0044] The second wavelength calculation unit 4172 calculates the wavelength of each phase voltage signal input to the AC motor 10 based on the timing at which each phase voltage signal becomes an intermediate voltage value detected by the intermediate voltage value detection unit 4121. The second wavelength calculation unit 4172 can calculate the period of one rotation of the AC motor 10 by calculating the difference between the timing (time) at which the intermediate voltage value is detected and the timing (time) at which the intermediate voltage value was detected immediately before. The second wavelength calculation unit 4172 can obtain the wavelength of each phase voltage signal input to the AC motor 10 by taking the reciprocal of the period obtained from the time of the intermediate voltage value. The second wavelength calculation unit 4172 may also calculate a moving average of the calculated wavelength. For example, in this case, the second wavelength calculation unit 4172 may calculate a moving average (for example, a simple moving average) of the wavelength calculated this time and the wavelengths calculated so far, and use the calculated moving average as the wavelength calculated this time. This makes it possible to suppress fluctuations in the wavelength output by the second wavelength calculation unit 4172 even when the fluctuations are large.

[0045] The third wavelength calculation unit 4173 calculates the wavelength of each phase voltage signal input to the AC motor 10 based on the wavelength calculated by the first wavelength calculation unit 4171 and the wavelength calculated by the second wavelength calculation unit 4172. In this embodiment, the third wavelength calculation unit 4173 calculates a moving average of the wavelength calculated by the first wavelength calculation unit 4171 and the wavelength calculated by the second wavelength calculation unit 4172, and sets the moving average as the wavelength of each phase voltage signal input to the AC motor 10. For example, the third wavelength calculation unit 4173 may calculate a simple average value without weighting for the most recent n wavelengths calculated by the first wavelength calculation unit 4171 and the most recent n wavelengths calculated by the second wavelength calculation unit 4172.

[0046] The third wavelength calculation unit 4173 may calculate a weighted moving average of the wavelength of each phase voltage signal input to the AC motor 10 calculated by the first wavelength calculation unit 4171 and the wavelength of each phase voltage signal input to the AC motor 10 calculated by the second wavelength calculation unit 4172, and may treat the weighted moving average as the wavelength of each phase voltage signal input to the AC motor 10. The weighted moving average refers to an average value weighted on each data. That is, in this embodiment, the third wavelength calculation unit 4173 may average a value obtained by multiplying the wavelength of each phase voltage signal calculated by the first wavelength calculation unit 4171 by a predetermined first weighting coefficient and a value obtained by multiplying the wavelength of each phase voltage signal calculated by the second wavelength calculation unit 4172 by a predetermined second weighting coefficient, and may treat the weighted moving average, which is the average value, as the wavelength of each phase voltage signal. Further, for example, the third wavelength calculation unit 4173 may calculate the average value of each of the values ​​obtained by multiplying the most recent n wavelengths calculated by the first wavelength calculation unit 4171 by the first weighting coefficient and each of the values ​​obtained by multiplying the most recent n wavelengths calculated by the second wavelength calculation unit 4172 by the second weighting coefficient, and treat the average value, which is a weighted moving average value, as the wavelength of each phase voltage signal. Note that the first weighting coefficient is a coefficient indicating the degree of influence that the wavelength of each phase voltage signal calculated by the first wavelength calculation unit 4171 has on the weighted moving average value, and the second weighting coefficient is a coefficient indicating the degree of influence that the wavelength of each phase voltage signal calculated by the second wavelength calculation unit 4172 has on the weighted moving average value. By treating the weighted moving average value calculated using the first weighting coefficient and the second weighting coefficient as the wavelength of each phase voltage signal in this way, it is possible to calculate a wavelength that reflects the actual wavelength of each phase voltage signal with high accuracy, and it is possible to more suitably suppress step-out.

[0047] The first weighting coefficient and the second weighting coefficient may be set arbitrarily, but the third wavelength calculation unit 4173 may change at least one of the first weighting coefficient and the second weighting coefficient according to the load of the AC motor 10 to calculate the weighted moving average of the wavelength. For example, when the fluctuation of the wavelength calculated by the first wavelength calculation unit 4171 is large and the fluctuation of the rotation speed of the AC motor 10 is considered to be large, the third wavelength calculation unit 4173 may increase the first weighting coefficient to calculate the weighted moving average of the wavelength of each phase voltage signal. More specifically, for example, the third wavelength calculation unit 4173 may change at least one of the first weighting coefficient and the second weighting coefficient so that the ratio of the first weighting coefficient to the second weighting coefficient is larger when the load fluctuation of the AC motor 10 is equal to or greater than a predetermined threshold value than when the load fluctuation is less than the threshold value. Furthermore, for example, the third wavelength calculation unit 4173 may change at least one of the first weighting coefficient and the second weighting coefficient so that the ratio of the first weighting coefficient to the second weighting coefficient increases as the load fluctuation of the AC motor 10 increases. Note that the load fluctuation of the AC motor 10 may be detected in any manner, but for example, the difference between the wavelength of the voltage signal previously calculated by the first wavelength calculation unit 4171 and the wavelength of the voltage signal previously calculated by the first wavelength calculation unit 4171 may be calculated as the load fluctuation.

[0048] The switching signal generating unit 418 generates a signal for switching the phase of the AC motor 10 to which the AC voltage is applied based on the calculated wavelength. That is, the switching signal generating unit 418 predicts the position of the rotor of the AC motor 10 based on the wavelength calculated by the wavelength calculating unit 417, and generates a signal for switching the phase of the AC motor 10 to which the AC voltage is applied so that the voltage direction is switched six times (every 60°) while the AC motor 10 rotates once in electrical angle (360° rotation). It can also be said that the switching signal generating unit 418 outputs a logic signal indicating a command of the phase to which the AC voltage is applied to the drive circuit 50, that is, a PWM (Pulse Width Modulation) signal.

[0049] The drive circuit 50 outputs a drive signal to each gate of six semiconductor switching elements (U+, V+, W+, U-, V-, W-) included in the inverter circuit in accordance with the PWM signal output by the switching signal generating unit 418. The drive circuit 50 may be realized by semiconductor switching elements such as field effect transistors (FETs) and IGBTs. That is, the drive circuit 50 may output a signal obtained by amplifying the PWM signal as necessary as a drive signal in order to drive the semiconductor switching elements.

[0050] (Control method and program) Next, the control method according to the present disclosure will be described with reference to FIG. 11. FIG. 11 is a flowchart showing the control method according to the present disclosure. The control method for the AC motor 10 will be described step by step with reference to FIG. 11. First, in the control method according to the present disclosure, each phase voltage signal of the AC motor 10 is acquired (step S110). Next, each acquired phase voltage signal is converted from analog to digital (step S120). Then, a time differential value of a virtual line L connecting the peak values ​​P of each phase voltage signal that has been converted from analog to digital is calculated (step S130). Then, an unnecessary signal is removed from the time differential value of the virtual line L connecting the peak values ​​P of each phase voltage signal (step S140). Then, a process of calculating an absolute value of the time differential value of each phase voltage signal from which the unnecessary signal has been removed is executed (step S150). Then, a process of holding the absolute value and sample-holding is executed (step S160). Then, a process of calculating a wavelength using the sample-held value is executed (step S170). Then, a PWM signal for driving the AC motor 10 is output based on the wavelength (step S180).

[0051] The above-mentioned control method may be executed by using the control device 40 or by any other means. Also, the above-mentioned control method may be executed by a program executed by a computer included in the control device 40.

[0052] According to the control method and program of this configuration, the wavelength of each phase voltage signal input to AC motor 10 can be calculated from the time differential value of each phase voltage signal, so that AC motor 10 can be controlled while suppressing the effects of fluctuations in the load on AC motor 10.

[0053] Second embodiment Next, the control device 40 according to the second embodiment will be described. The control device 40 according to the second embodiment has the same configuration as the control device 40 according to the first embodiment, except that it does not have the absolute value calculation unit 414 and the processing of the unnecessary signal removal unit 413 is different. Therefore, the parts of the configuration of the control device 40 according to the second embodiment that differ from the configuration of the control device 40 according to the first embodiment will be described.

[0054] The unnecessary signal removal unit 413 outputs a correction signal (second correction signal) obtained by removing unnecessary signals that are constant for a period of time less than a predetermined time in the time differential value of the virtual line L connecting the peak values ​​P of the phase voltage signals of the AC motor 10, as well as signals with negative values. That is, the unnecessary signal removal unit 413 obtains, as the second correction signal, a time waveform signal obtained by removing (setting to zero) the time waveform of the time differential value of the virtual line L during a time period during which the time differential value is kept constant and during a time period during which the time differential value is negative.

[0055] Fig. 12 is a diagram showing the result of signal processing by the control device according to the second embodiment. As shown in Fig. 12, in the signal processing by the control device 40 according to the second embodiment, the unnecessary signal remover 413 removes signals with negative values ​​in addition to signals that are constant for a period less than a predetermined time in the time differential value of each phase voltage signal, so that the second correction signal indicating the signal after the unnecessary signal removal process is a signal in which only positive values ​​remain.

[0056] According to this configuration, since the control device 40 does not have the absolute value calculation unit 414, the calculation load on the control unit 41 is reduced, and the calculation resources of the control unit 41 can be allocated to other calculations.

[0057] Third embodiment Next, the control device 40 according to the third embodiment will be described. The control device 40 according to the third embodiment has the same configuration as the control device 40 according to the first embodiment, except that it does not have the absolute value calculation unit 414 and the processing of the unnecessary signal removal unit 413 and the merging unit 415 is different. Therefore, the parts of the configuration of the control device 40 according to the third embodiment that differ from the configuration of the control device 40 according to the first embodiment will be described.

[0058] The unnecessary signal removal unit 413 outputs a correction signal (third correction signal) obtained by removing positive signals in addition to signals that are constant for a period of time less than a predetermined time in the time differential value of each phase voltage signal of the AC motor 10. That is, the unnecessary signal removal unit 413 obtains, from the time waveform of the time differential value of the virtual line L, a signal of a time waveform obtained by removing (setting to zero) the time waveform of the time differential value in a time period in which the time differential value is kept constant does not satisfy a predetermined time and in a time period in which the time differential value is positive, as the third correction signal.

[0059] The merging unit 415 inverts the sign of the third correction signal and calculates a total signal by merging the third correction signals of each phase. As described above, the unnecessary signal removal unit 413 of the control device 40 according to the third embodiment regards positive values ​​of the voltage signals of each phase of the AC motor 10 as unnecessary signals and removes them. Therefore, only negative value signals remain in the third correction signal output by the unnecessary signal removal unit 413. The merging unit 415 converts negative values ​​of the third correction signal to positive values ​​and calculates a total signal by merging the third correction signals of each phase.

[0060] FIG. 13 is a diagram showing the result of signal processing of the control device according to the third embodiment. As shown in FIG. 13, in the signal processing of the control device 40 according to the third embodiment, the unnecessary signal removal unit 413 removes signals with positive values ​​in addition to signals that are constant for a period less than a predetermined time in the time differential value of each phase voltage signal, so that the third correction signal indicating the signal after the unnecessary signal removal process is a signal with only negative values ​​remaining. Then, the merging unit 415 converts the negative values ​​of the third correction signal to positive values ​​and calculates a total signal by merging the third correction signals of each phase, so that the total signal of the control device 40 according to the third embodiment is a signal with a positive value.

[0061] According to this configuration, since the control device 40 does not have the absolute value calculation unit 414, the calculation load on the control unit 41 is reduced, and the calculation resources of the control unit 41 can be allocated to other calculations.

[0062] (Fourth embodiment) Next, the control device 40 according to the fourth embodiment will be described. The control device 40 according to the fourth embodiment has the same configuration as the control device 40 according to the first embodiment, except for the processing of the analog-to-digital conversion unit 411. Therefore, the parts of the configuration of the control device 40 according to the fourth embodiment that differ from the configuration of the control device 40 according to the first embodiment will be described.

[0063] In the first embodiment, the phase voltage signals of the AC motor 10 are acquired with respect to ground (0 V), but in the fourth embodiment, the analog-to-digital conversion unit 411 acquires the phase voltage signals of the AC motor 10 with respect to the positive power supply voltage Vcc. That is, the analog-to-digital conversion unit 411 acquires the difference between the phase voltage signals of the AC motor 10 and the voltage value of the output voltage of the positive power supply 30 as the phase voltage signals of the AC motor 10.

[0064] Fig. 14 is a diagram showing each phase voltage signal acquired by an analog-digital conversion unit of the control device according to the fourth embodiment. As shown in Fig. 14, each phase voltage signal acquired by the analog-digital conversion unit 411 of the control device 40 according to the fourth embodiment is a difference from the voltage value of the output voltage of the positive power supply 30, and therefore becomes a signal whose value fluctuates with the voltage value of the output voltage of the positive power supply 30 as an upper limit.

[0065] In this configuration, as with the control device 40 according to the first embodiment, it is possible to provide a control device 40 that is capable of applying a desired torque to the load of the AC motor 10, even when there is a sudden load fluctuation that is shorter than the wavelength of the AC motor 10.

[0066] FIG. 15 is a diagram showing an example of a virtual line connecting the peak values ​​of each phase voltage signal in the fourth embodiment. In the first embodiment, as shown in FIG. 4 and the like, each phase voltage signal changes while its voltage value is maintained at 0V or more and at a positive power supply voltage Vcc or less (for example, changes between 0V and 12V). However, in the fourth embodiment, each phase voltage signal changes while its voltage value is maintained at -Vcc or more and at 0V or less (for example, changes between -12V and 0V) as shown in FIG. 15. In this case, the differential value calculation unit 4122 may calculate the absolute value of the peak value P of each phase voltage signal from the peak value P, and calculate a time differential value of a virtual line L connecting the peak values ​​P for each time based on the absolute value of the peak value P for each time of each phase voltage signal. 15 is a line connecting the peak values ​​P, but the virtual line L connecting the absolute values ​​of the peak values ​​P has the same shape as the virtual line L in the first embodiment with the positive and negative signs reversed, and the time differential value can be calculated in the same manner as in the first embodiment. Since the method of calculating the time differential value other than taking the absolute value is the same as in the first embodiment, detailed description will be omitted. However, in this case, for example, when the voltage signal value is less than a predetermined threshold value TH (for example, less than 0 V), the differential value calculation unit 4122 may determine that it is outside the range of the predetermined threshold value TH and detect the peak value P.

[0067] (Composition and Effects) The control device 40 according to the present disclosure includes: A motor control device for controlling an AC motor, comprising: an analog-to-digital conversion unit that acquires a voltage in wiring connecting the inverter and the AC motor and converts the voltage into an analog-to-digital signal to generate a phase voltage signal, which is a voltage of each phase of the AC motor; and an analog-to-digital conversion unit that acquires, as a peak value P of each phase voltage signal, a voltage value of each phase voltage signal at any timing between a first timing at which the voltage value of each phase voltage signal rises or falls and a second timing at which the voltage value of each phase voltage signal rises or falls after the first timing, andA differential value calculation unit 4122 calculates a time differential value on a virtual line L connecting the peak values ​​P of the respective phase voltage signals, and a differential value calculation unit 4123 calculates a time differential value of the AC motor 10 from the time differential value. The rotation waveform of the AC motor 10 is the reciprocal of the period of one rotation of the and a switching signal generating unit 418 that generates a signal for switching the phase of the AC motor 10 based on the calculated wavelength.

[0068] According to this configuration, even if there is a sudden load fluctuation that is shorter than the wavelength of the AC motor 10, the AC motor 10 can be controlled based on the calculated wavelength, so that loss of synchronization can be prevented and the desired torque can be applied to the load of the AC motor 10.

[0069] In the present disclosure, each phase voltage signal is a PWM signal, and the differential value calculation unit 4122 acquires the value of each phase voltage signal at any timing between a first timing t1 at which the value of each phase voltage signal rises and a second timing t2 at which the value of each phase voltage signal falls after the first timing t1 as a peak value P of each phase voltage signal. By acquiring the peak value P in this manner, the time differential value of the virtual line L connecting the peak values ​​P can be calculated with high accuracy. Furthermore, although the reading of the peak value P may differ depending on the microcomputer, according to the present disclosure, the voltage signal value between the first timing t1 at which the voltage signal value rises and the second timing t2 at which the voltage signal value falls can be set as the peak value, so that the adjustment of the reading timing is not complicated, and the processing can be prevented from becoming complicated.

[0070] The differential value calculation unit 4122 according to the present disclosure obtains the value of each phase voltage signal at midpoint timing t3, which is the midpoint between the first timing t1 and the second timing t2, as the peak value P of each phase voltage signal. By obtaining the peak value P in this manner, it is possible to reduce the influence of edges in the PWM signal of each phase voltage signal, and it is possible to calculate the time differential value of the virtual line L connecting the peak values ​​P with high accuracy.

[0071] The control device 40 according to the present disclosure includes an unnecessary signal removal unit 413 that outputs a correction signal obtained by removing unnecessary signals, which are signals whose time differential value is maintained at a constant value for less than a predetermined time, from the time differential value of each phase, a merging unit 415 that calculates a total signal by merging the correction signals of each phase, a sample hold unit 416 that calculates a sample hold signal corrected so as to maintain the value of the total signal at a constant value until it changes to a value other than zero, and a proportionality coefficient by multiplying the reciprocal of the value of the sample hold signal, Rotation waveform of AC motor 10 The first wavelength calculation unit 4171 further calculates the wavelength of the light.

[0072] According to this configuration, even if a sudden load change occurs that is shorter than the wavelength of the AC motor 10, a desired torque can be applied to the load of the AC motor 10.

[0073] The control device 40 according to the present disclosure includes an intermediate voltage value detection unit 4121 that detects the timing at which each phase voltage signal of the AC motor 10 becomes an intermediate voltage value from the respective phase voltage signals of the AC motor 10, and a control unit 4122 that controls the AC motor 10 based on the detected timing at which the intermediate voltage value is reached. Rotational waveform of The second wavelength calculation unit 4172 calculates the wavelength of the AC motor 10 calculated by the first wavelength calculation unit 4171. Rotational waveform of and the wavelength of the AC motor 10 calculated by the second wavelength calculation unit 4172. Rotational waveform of The switching signal generating unit 418 generates a switching signal based on the moving average calculated by the third wavelength calculating unit 4173.

[0074] According to this configuration, the wavelength of the AC motor 10 is calculated based on the moving average of the wavelength calculated by the first wavelength calculation unit 4171 and the wavelength calculated by the second wavelength calculation unit 4172, thereby improving the accuracy of the wavelength calculation.

[0075] The third wavelength calculation unit 4173 of the control device 40 according to the present disclosure calculates the wavelength of the light emitted from the first wavelength calculation unit 4171. Rotation waveform of AC motor 10 and the wavelength calculated by the first wavelength calculation unit 4171 Rotation waveform of AC motor 10The value calculated by the second wavelength calculation unit 4172 is multiplied by a first weighting coefficient indicating the degree of influence of the wavelength on the weighted average. Rotation waveform of AC motor 10 and the wavelength calculated by the second wavelength calculation unit 4172 Rotation waveform of AC motor 10 The switching signal generating unit 418 generates a switching signal based on the weighted moving average calculated by the third wavelength calculating unit 4173. ...

[0076] According to this configuration, the weighted moving average can be calculated by setting the weighting coefficients of the wavelength calculated by the first wavelength calculation unit 4171 and the wavelength calculated by the second wavelength calculation unit 4172, respectively. Rotational waveform of This makes it possible to maintain the calculation accuracy of the wavelength.

[0077] The third wavelength calculation unit 4173 of the control device 40 according to the present disclosure changes at least one of the first weighting coefficient and the second weighting coefficient in accordance with the load on the AC motor 10, and calculates a weighted moving average of the wavelength.

[0078] According to this configuration, when the load fluctuation of the AC motor 10 is large, the first weighting coefficient of the wavelength calculated by the first wavelength calculation unit 4171 based on the time differential value is increased, and the first weighting coefficient and the second weighting coefficient can be set according to the load fluctuation. This makes it possible to calculate a weighted moving average value of the wavelength according to the load fluctuation. Rotation waveform of AC motor 10 This allows the actual wavelength to be reflected with high accuracy, and step-out can be more effectively suppressed.

[0079] The program according to the present disclosure is A program for causing a computer to execute control of an AC motor, the program comprising the steps of: applying a voltage to the AC motor from an inverter using a 120° energization method; acquiring a voltage in wiring connecting the inverter and the AC motor and performing analog-to-digital conversion to generate phase voltage signals, which are voltages of each phase of the AC motor; acquiring, as a peak value P of each phase voltage signal, a voltage value of each phase voltage signal at any timing between a first timing at which the voltage value of each phase voltage signal rises or falls and a second timing at which the voltage value of each phase voltage signal rises or falls after the first timing; A step of calculating a time differential value on a virtual line L connecting peak values ​​P of each phase voltage signal, and calculating a time differential value of the AC motor 10 from the time differential value. The rotation waveform of the AC motor 10 is the reciprocal of the period of one rotation of the and generating a signal for switching the phase of the AC motor 10 based on the calculated wavelength.

[0080] According to this configuration, even if a sudden load fluctuation occurs that is shorter than the wavelength of the AC motor 10, the AC motor 10 can be controlled based on the calculated wavelength, thereby preventing loss of synchronization and providing the desired torque to the motor load.

[0081] Although the embodiment of the present disclosure has been described above, the embodiment is not limited by the contents of this embodiment. In addition, the above-mentioned components include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-mentioned components can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the gist of the above-mentioned embodiment. [Explanation of symbols]

[0082] 100 Motor System 10 AC motor 20 Inverter 30 Positive power supply 40 Control device (motor control device) 41 Control section 411 Analog-to-digital conversion section 412 Signal Processing Unit 4121 Intermediate voltage detector 4122 Differential value calculation section 413 Unnecessary signal removal section 414 Absolute value calculation unit 415 Merge Department 416 Sample and hold section 417 Wavelength calculation section 4171 First wavelength calculation section 4172 Second wavelength calculation section 4173 Third wavelength calculation section 418 Switching signal generator 42 Storage section 50 Drive circuit

Claims

1. A motor control device for controlling an AC motor, the AC motor being supplied with a voltage from an inverter using a 120° energization method; an analog-to-digital conversion unit that acquires a voltage in a wiring that connects the inverter and the AC motor and converts the voltage into an analog-to-digital signal to generate a phase voltage signal that is a voltage of each phase of the AC motor; a differential value calculation unit that acquires, as a peak value of each phase voltage signal, a voltage value of each phase voltage signal at any timing between a first timing at which the voltage value of each phase voltage signal rises or falls and a second timing at which the voltage value of each phase voltage signal rises or falls after the first timing, and calculates a time differential value of a virtual line connecting the peak values ​​of each phase voltage signal; a wavelength calculation unit that calculates a wavelength of a rotation waveform of the AC motor, which is an inverse number of a period of one rotation of the AC motor, from the time differential value; a switching signal generating unit that generates a signal for switching a phase of the AC motor based on the calculated wavelength; A motor control device comprising:

2. the differential value calculation unit acquires, as a peak value of each of the phase voltage signals, a voltage value of each of the phase voltage signals at a midpoint timing that is a midpoint between the first timing and the second timing; The motor control device according to claim 1 .

3. an unnecessary signal removal unit that removes unnecessary signals, which are signals whose time differential value is kept constant for less than a predetermined time, from the time differential value of each phase to generate a correction signal; a merging unit for calculating a total signal by merging the correction signals of the respective phases; a sample-and-hold unit for calculating a sample-and-hold signal corrected so as to keep the value of the sum signal constant until it changes to a value other than zero; a first wavelength calculation unit that calculates a wavelength of a rotation waveform of the AC motor by multiplying the reciprocal of the value of the sample-and-hold signal by a proportionality coefficient, The motor control device according to claim 1 or 2.

4. an intermediate voltage value detection unit that detects, from the respective phase voltage signals, a timing at which each phase voltage signal becomes an intermediate voltage value; a second wavelength calculation unit that calculates a wavelength of a rotation waveform of the AC motor based on the detected timing at which the intermediate voltage value is reached; a third wavelength calculation unit that calculates a moving average of a wavelength of the rotation waveform of the AC motor calculated by the first wavelength calculation unit and a wavelength of the rotation waveform of the AC motor calculated by the second wavelength calculation unit, The switching signal generation unit generates a switching signal based on the moving average calculated by the third wavelength calculation unit. The motor control device according to claim 3.

5. The third wavelength calculation unit is a value obtained by multiplying the wavelength of the rotation waveform of the AC motor calculated by the first wavelength calculation unit by a first weighting coefficient indicating a degree of influence of the wavelength of the rotation waveform of the AC motor calculated by the first wavelength calculation unit on a weighted average; a value obtained by multiplying the wavelength of the rotation waveform of the AC motor calculated by the second wavelength calculation unit by a second weighting coefficient indicating a degree of influence of the wavelength of the rotation waveform of the AC motor calculated by the second wavelength calculation unit on a weighted average; Calculate the weighted moving average of The switching signal generation unit generates a switching signal based on the weighted moving average calculated by the third wavelength calculation unit. The motor control device according to claim 4.

6. the third wavelength calculation unit calculates a weighted moving average of the wavelength by changing at least one of the first weighting coefficient and the second weighting coefficient in accordance with a load of the AC motor. The motor control device according to claim 5.

7. A motor control device for controlling an AC motor, wherein a voltage is applied to the AC motor from an inverter using a 120° energization method; a sample-and-hold unit that samples and holds an analog value of a voltage in a wiring that connects the inverter and the AC motor at a predetermined timing to obtain an analog value of each phase voltage signal that is a voltage of each phase of the AC motor; a differential value calculation unit that detects the sampled and held analog values ​​of the phase voltage signals as peak values ​​of the phase voltage signals and calculates a time differential value on a virtual line connecting the peak values; a wavelength calculation unit that calculates a wavelength of a rotation waveform of the AC motor, which is an inverse number of a period of one rotation of the AC motor, from the time differential value; a switching signal generating unit that generates a signal for switching a phase of the AC motor based on the calculated wavelength; Equipped with Motor control device.

8. A program for causing a computer to execute control of an AC motor, the AC motor being supplied with a voltage from an inverter using a 120° energization method; generating respective phase voltage signals which are voltages of respective phases of the AC motor by acquiring and analog-to-digital converting a voltage in a wiring connecting the inverter and the AC motor; acquiring, as a peak value of each phase voltage signal, a voltage value of each phase voltage signal at any timing between a first timing at which the voltage value of each phase voltage signal rises or falls and a second timing at which the voltage value of each phase voltage signal rises or falls after the first timing, and calculating a time differential value of a virtual line connecting the peak values ​​of each phase voltage signal; calculating a wavelength of a rotation waveform of the AC motor, which is an inverse of a period of one rotation of the AC motor, from the time differential value; generating a signal for switching a phase of the AC motor based on the calculated wavelength; to cause a computer to execute program.

9. A program for causing a computer to execute control of an AC motor, the AC motor being supplied with a voltage from an inverter using a 120° energization method; a step of sampling and holding an analog value of a voltage in a wiring connecting the inverter and the AC motor at a predetermined timing to obtain an analog value of each phase voltage signal which is a voltage of each phase of the AC motor; detecting the sampled and held analog values ​​of the phase voltage signals as peak values ​​of the phase voltage signals, and calculating time differential values ​​on imaginary lines connecting the peak values; calculating a wavelength of a rotation waveform of the AC motor, which is an inverse of a period of one rotation of the AC motor, from the time differential value; generating a signal for switching a phase of the AC motor based on the calculated wavelength; to cause a computer to execute program.

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