JP5228460B2 - Motor control device - Google Patents

Description

  The present invention relates to a method of reducing calculation delay due to digital processing and increasing the response of motor control in an inverter circuit that drives a motor by PWM control.

  The method of controlling the motor by PWM (Pulse Width Modulation) control has a configuration as shown in FIG. 11, and digital control using a microprocessor is widely performed. In order to control the motor, it is necessary to detect the motor current flowing through the motor and the rotor position of the motor. In the digital control, the motor information is detected at every predetermined sampling period, and the torque required by the motor is output. Thus, PWM control is performed to generate a PWM voltage command value by calculating the motor current so as to be equal to the command value, and to generate a pulse for turning on / off the semiconductor element to the PWM inverter circuit.

FIG. 11 shows a conventional motor control device. Based on a triangular wave signal of a triangular wave generator that generates a carrier cycle that is a cycle for controlling the motor by PWM control, a motor current and a rotor position are detected, and a timing signal for current control is generated by a timing generation circuit. FIG. 12 shows a waveform of a timing signal of a conventional motor control device. In the PWM control, the switching operation of the semiconductor element is difficult to be performed in the vicinity of the apex of the triangular wave signal. Therefore, a method of sampling the motor current at the timing of the apex of the triangular wave has been proposed (for example, see Patent Document 1). .

Further, as a method for improving the current control response, a method is proposed in which the current sampling timing is set a predetermined time before the apex of the triangular wave signal, and the PWM voltage command value is updated at the apex of the next triangular wave (for example, , See Patent Document 2).
JP-A-9-121558 JP 2005-31274 A

  However, in the method of Patent Document 1, a PWM voltage command value is generated after a current control calculation is performed by a microprocessor using the detected motor current value. However, the PWM voltage command value is reflected. There is a delay due to the timing of the next vertex of the triangular wave signal, and there is a limit to improving the response of current control (see FIG. 12).

  On the other hand, the method of Patent Document 2 has a problem that it is affected by switching noise of PWM control because the timing of current sampling is set before the apex of the triangular wave signal by the calculation time of current control by the microprocessor. (See FIG. 13).

  As a method for reducing the influence of switching noise in PWM control, as shown in FIG. 14, the time required for the current control calculation is set on both sides of the apex of the triangular wave signal, and the current sampling timing is made close to the apex of the triangular wave signal. There is. However, when the PWM voltage command value is in the vicinity of the apex of the triangular wave signal, switching of the semiconductor element may occur twice between the apexes of the triangular wave signal, increasing the heat generation of the semiconductor element.

  By limiting the maximum and minimum values of the PWM voltage command value, it is possible to prevent the semiconductor element from switching twice. However, the voltage that can be output from the PWM inverter circuit is reduced, and the motor is reduced. There is a problem that the output power of the power supply decreases.

  The present invention solves the above-described conventional problems, and reduces the influence of switching noise in PWM control without reducing the voltage that can be output from the PWM inverter circuit, and without increasing the heat generation of the semiconductor element. An object of the present invention is to provide a motor control device that enhances control responsiveness.

In order to solve the above problems, the motor control device according to claim 1 and 2 is a PWM inverter circuit that converts a DC voltage into an AC voltage by turning on and off a semiconductor element and supplies electric power to the motor; A gate control unit for giving an ON / OFF command to the semiconductor element of the PWM inverter circuit, a current detector for detecting a motor current value flowing through the motor, and a value for the detected motor current value at regular intervals for digital calculation. A current sample hold circuit for holding, a triangular wave generator for generating a triangular wave signal that becomes a PWM modulation period, a current control unit for generating a voltage value to be applied to the motor, and a voltage value generated by the current control unit for PWM A PWM generator that updates the voltage command value, and a PWM signal that is generated by comparing the magnitudes of the PWM voltage command value and the triangular wave signal. A comparator for outputting to the serial gate control unit, said current sample-and-hold circuit holds the motor current value, a current sample-and-hold timing signal which the current control unit performs the digital operation, the PWM generator is the PWM voltage command A timing generation circuit that generates a PWM signal update timing signal for updating a value, and takes time (current control calculation time) for the current control unit to perform digital calculation on both sides of the apex of the triangular wave signal. The current sample hole immediately before the current control calculation time
Outputs de timing signal, and monitoring changes in the PWM signal from the comparator for each between the upper and lower vertices of the triangular wave signal, immediately after the current control operation time when the PWM signal from the comparator does not change When the PWM signal update timing signal is generated and the PWM signal from the comparator changes, the PWM signal update timing signal is generated at the next vertex of the triangular wave signal or not generated .

According to a third aspect of the present invention , the motor control device according to the third aspect is configured such that the PWM signal from the comparator is monitored independently for each phase, and is reflected in the generation of the PWM signal update timing signal only in the monitored phase. Good.

The motor control device according to claim 4 monitors the PWM signal from the comparator in all phases at once, and only when the output signal of all phases does not change, the PWM signal update timing signal for all phases. The PWM signal update timing signal for all phases may be generated at the next vertex of the triangular wave signal when the output signal changes in any phase .

The motor control device according to claim 5 monitors the PWM signal from the comparator in all phases at once, and only when the output signals of all phases do not change, the PWM signal update timing signal for all phases. The PWM signal update timing signal for all phases may not be generated when the output signal changes in any phase .

Further, in the motor control device according to claim 6 , the timing generation circuit further generates a switching permission signal that permits the semiconductor element to be turned ON / OFF, and the PWM signal from the comparator does not change. In some cases, the switching permission signal may be generated.

According to the motor control device of any one of claims 1 to 6 , the influence of PWM control switching noise can be reduced and the heat generation of the semiconductor element can be increased without reducing the voltage that can be output from the PWM inverter circuit. In addition, the response of current control can be improved.

In addition, according to the motor control device of the third aspect , the responsiveness of the motor control can be improved.

Furthermore, according to the motor control device of the fourth aspect , the responsiveness of the motor control can be improved without breaking the voltage balance of all phases.

A PWM inverter circuit that converts a DC voltage into an AC voltage by turning ON / OFF the semiconductor element and supplies electric power to the motor, a gate control unit that gives an ON / OFF command to the semiconductor element of the PWM inverter circuit, and a motor A current detector for detecting the motor current value flowing through the current, a current sample-and-hold circuit for holding the detected motor current value at a constant interval for digital calculation, and a triangular wave for generating a triangular wave signal that becomes a PWM modulation cycle A generator, a current control unit that generates a voltage value to be applied to the motor, a PWM generation unit that updates the voltage value generated by the current control unit as a PWM voltage command value, the PWM voltage command value and the triangular wave signal a comparator for outputting a PWM signal to the gate control unit which is generated by comparing the magnitude of said current sample-and-hold circuit Holding the serial motor current value, a current sample-and-hold timing signal which the current control unit performs the digital operation, a timing generation circuit for generating a PWM signal update timing signal the PWM generation unit updates the PWM voltage instruction value The current control unit performs a digital computation time (current control computation time) on both sides of the apex of the triangular wave signal, and the timing generation circuit includes the current support immediately before the current control computation time.
Outputs sample hold timing signal, monitor the changes in the PWM signal from the comparator for each between the upper and lower vertices of the triangular wave signal, immediately after the current control operation time when the PWM signal from the comparator does not change The PWM signal update timing signal is generated at the same time, and when the PWM signal from the comparator changes, the PWM signal update timing signal is generated or not generated at the next vertex of the triangular wave signal. It is a motor control device.

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a main block diagram of a motor control device, FIG. 2 is a block diagram of a PWM inverter circuit and a gate control unit, and FIG. 3 shows signal waveforms in each block. The role of each block will be described below.

  In FIG. 1, 1 is a current command for determining a current to be supplied to the motor, 6 is a motor, 5 is a PWM inverter circuit, 11a is a gate control unit, 14 is a rotary encoder for detecting the position of the rotor, and 16 (16U, 16V) are This is a shunt resistor that converts the motor current flowing in the U phase and V phase into a voltage.

  Since motors used in the FA servo field require miniaturization and high-speed response, three-phase AC synchronous machines are widely used.

  The PWM inverter circuit 5 is configured as shown in FIG. In the case of a three-phase motor, a power element 53 (53U, 53V, 53W, 53X, 53Y, 53Z), which is six semiconductor elements (IGBT, etc.) and a recovery diode 54 (54U, 54V, 54W, 54X, 54Y, 54Z). Each power element 53 is amplified by a pre-drive circuit 52 (52U, 52V, 52W, 52X, 52Y, 52Z) to a power source (generally about 15V) necessary for turning on the power element 53 to turn on / off the power element 53. Turn it off.

  The gate control unit 11a separates the PWM signal for three phases into an upper phase and a lower phase, and the gate control circuit 47a is turned off with a delay on the side to be turned on so as not to be turned on simultaneously when switching the switching. The logical configuration is such that a period is provided.

  The current detection of the motor 6 uses the fact that the sum of the motor currents of the three-phase motor becomes 0, detects the two-phase motor current, and obtains the remaining one-phase motor current by calculation. As described above, the motor current detection method using the two shunt resistors 16 is generally adopted from the viewpoint of cost reduction.

  Further, when the output power is large, the loss of the shunt resistor 16 becomes large, so that a CT (current-voltage converter) composed of a Hall element, a coil, or the like is often employed. The motor current is converted into a voltage by the shunt resistor 16 and CT, and digitally converted by the current detector 12. An AD converter is used as the current detector 12 that converts an analog signal into digital data. In digital control by a microcomputer (hereinafter referred to as a microcomputer), arithmetic processing is performed at predetermined intervals. Therefore, the motor current is converted into digital data by an AD converter at each arithmetic cycle, and the digital data of the motor current is converted by a current sample and hold circuit 15. It is configured to hold and perform arithmetic processing.

The rotary encoder 14 includes an optical type and a magnetic type, and high-precision positioning is required in the FA servo field. Therefore, the rotary encoder 14 having a high resolution such as a 17-bit resolution is used. Further, in order to improve the responsiveness of the motor, it is effective to increase the resolution of the rotary encoder 14, and those having a resolution of 17 bits or more are beginning to be adopted.

  The rotor position information 44 is converted into serial data and transmitted from the rotary encoder 14, and the position detector 13 converts the serial data into parallel data to generate a rotor position detection value 45. When the rotor position information 44 is used for digital control, the position sample hold circuit 9 holds the rotor position detection value 45 and performs arithmetic processing at predetermined intervals, like the motor current.

  Next, the triangular wave generator 7 and the timing generation circuit 8a for generating the timing of PWM control and generating the carrier frequency will be described.

  The triangular wave generator 7 is generated using an up / down counter using a clock such as a microcomputer. The value of the vertex is set, and when the counter value of the up / down counter is counted up from 0 and reaches the vertex, the count is switched to down count. By repeating this, a triangular wave signal 34 is generated.

  When the frequency of the triangular wave signal 34 is the carrier frequency for PWM control and the clock is 10 MHz, the carrier frequency becomes 10 kHz if the apex is set to 500. The triangular wave signal 34 generated by the triangular wave generator 7 is used as a signal to be compared with the PWM voltage command value by PWM control.

  The timing generation circuit 8a receives the triangular wave signal 34 from the triangular wave generator 7, and generates an interrupt signal for starting the operation of each block. In the generation of the interrupt signal, a timing value for generating an interrupt is set for the count value of the triangular wave signal 34, and a pulse is generated when the value becomes equal to the count value.

  The current control unit 2 calculates the voltage command value 31 (31U, 31V) for each phase from the motor current sampling value 43 held by the current sample hold circuit 15, the rotor position sampling value 46 held by the position sample hold circuit 9, and the current command 1. , 31W) is obtained by calculation. In digital control using a microcomputer, it is generally obtained by dq conversion and PI control (proportional / integral control).

  The PWM generation unit 3 adjusts the voltage command value 31 of each phase obtained by the current control unit 2 to the amplitude level of the triangular wave signal 34 used for PWM control, and converts it into a PWM voltage command value 32 (32U, 32V, 32W). . When the maximum amplitude of the triangular wave signal 34 is half, the voltage command value 31 of each phase is zero, and the PWM duty is 50%. Further, when the triangular wave signal 34 has the maximum amplitude, the voltage command value 31 of each phase is maximum, and the PWM duty is 100%.

  The comparator 4 compares the PWM voltage command value 32 obtained by the PWM generation unit 3 with the triangular wave signal 34 generated by the triangular wave generator 7, and when the PWM voltage command value 32 is large, the PWM signal is set to H. Let PWM signal be L. When the calculation of the voltage command value 31 is positive and negative, this logic can be inverted.

  The above is the role of each main block, and the contents implemented to improve the responsiveness will be described with reference to FIG. Although FIG. 3 shows an example of the U phase, the V phase and the W phase have the same configuration.

The timing generation circuit 8a outputs a current sample hold timing signal 38 to the current sample hold circuit 15 and the current detector 12 a predetermined time before the apex of the triangular wave signal 34,
Obtain the motor current sampling value for each phase. After the motor current is detected, a calculation process performed by the current control unit 2 is performed. This calculation processing time depends on the processing capacity of the microcomputer, but can be processed in a time of about 5 to 10 μs.

Here, the timing generation circuit 8a outputs the PWM signal update timing signal 35U to the PWM generation unit 3 after a predetermined time from the apex of the triangular wave signal 34 , and converts the voltage command value 31 of each phase obtained by the current control unit 2. Each phase PWM voltage command value 32 is processed and output to the comparator 4, and the PWM signal 36 is output by comparing the triangular wave signal 34 with the magnitude.

The output timings of the current sample hold timing signal 38 and the PWM signal update timing signal 35U are distributed back and forth as shown in FIG. 3, with the calculation processing time (current control calculation time) of the current control unit 2 based on the apex of the triangular wave signal 34. If it is set so as to be, it can be made less susceptible to noise.

  Here, as indicated by a circle (1) in FIG. 3, the PWM signal 36U may change between the apex of the triangular wave signal 34 and the PWM signal update timing 35U. The timing generation circuit 8a sets the interval between the vertices of the triangular wave signal 34 as the SW monitoring interval, and when the PWM signal 36U changes during the interval from the apex of the triangular wave signal 34 to the output of the PWM signal update timing signal 35U, the PWM signal update timing signal 35U is not output, the PWM signal update timing signal 35U is output at the next vertex of the triangular wave signal 34, and the PWM voltage command value 32U is updated.

  According to the motor control apparatus of the first embodiment, the result calculated by the current control unit can be immediately reflected as the PWM voltage command value, so that the responsiveness of the motor control can be improved. Furthermore, since the motor current is detected near the apex of the triangular wave signal, it is not easily affected by the switching of the semiconductor element. Furthermore, since the number of times of switching of the semiconductor element in the SW monitoring section is limited to one, the influence of noise and heat generation due to an increase in the number of times of switching of the semiconductor element does not increase. Furthermore, since the PWM voltage command value can be set up to the top of the triangular wave signal, the voltage utilization rate is not reduced.

  A second embodiment of the present invention will be described with reference to FIG. The only difference from the first embodiment is the output configuration of the PWM signal update timing signal, which will be described.

  FIG. 4 shows a signal waveform in each block. When the PWM signal 36U changes between the apex of the triangular wave signal 34 and the PWM signal update timing 35U as indicated by a circle (2), the timing generating circuit 8a has a triangular wave. The configuration is such that the interval between the vertices of the signal 34 is the SW monitoring interval, and the PWM signal update timing signal 35U is not output when the PWM signal 36U changes from the apex of the triangular wave signal 34 until the output of the PWM signal update timing signal 35U. To do. The PWM voltage command value 32 is updated to a new value by the calculation of the next cycle and reflected at the timing of the next PWM signal update timing signal 35U.

  According to the motor control apparatus of the second embodiment, the result calculated by the current control unit can be immediately reflected as the PWM voltage command value, so that the responsiveness of the motor control can be improved. Furthermore, since the motor current is detected near the apex of the triangular wave signal, it is not easily affected by the switching of the semiconductor element. Furthermore, since the number of times of switching of the semiconductor element in the SW monitoring section is limited to one, the influence of noise and heat generation due to an increase in the number of times of switching of the semiconductor element does not increase. Furthermore, since the PWM voltage command value can be set up to the top of the triangular wave signal, the voltage utilization rate is not reduced.

  A third embodiment of the present invention will be described with reference to FIGS. The difference from the first and second embodiments is that the timing generation circuit 8b monitors changes in the PWM signals 36U, 36V, and 36W, which will be described.

  FIG. 5 is a principal block diagram of the motor control apparatus according to the third embodiment, and FIG. 6 shows signal waveforms in the respective blocks. The timing generation circuit 8b in FIG. 5 monitors whether the PWM signals 36U, 36V, and 36W have changed between the apex of the triangular wave signal 34 and the PWM signal update timing signal 35. When there is a signal change even in one phase during this period, the PWM signal update timing signal 35 is not generated for all phases, and the PWM signal update timing signal 35 is generated at the next vertex of the triangular wave signal 34.

  FIG. 6 shows a U-phase signal waveform. When there is a change in the PWM signal in the V phase or the W phase as indicated by a circle (3), the PWM signal update timing signal 35 is not generated. The command value 32U is not updated at this timing, but is updated at the next vertex of the triangular wave signal 34.

  According to the motor control device of the third embodiment, the result calculated by the current control unit can be immediately reflected as a PWM voltage command value without destroying the voltage balance of all phases applied to the motor. Can be increased. Furthermore, since the motor current is detected near the apex of the triangular wave signal, it is not easily affected by the switching of the semiconductor element. Furthermore, since the number of times of switching of the semiconductor element in the SW monitoring section is limited to one, the influence of noise and heat generation due to an increase in the number of times of switching of the semiconductor element does not increase. Furthermore, since the PWM voltage command value can be set up to the top of the triangular wave signal, the voltage utilization rate is not reduced.

  Example 4 will be described with reference to FIG. The only difference from the third embodiment is the output configuration of the PWM signal update timing signal, which will be described.

  FIG. 7 shows signal waveforms in each block. When the PWM signal 36U changes between the apex of the triangular wave signal 34 and the PWM signal update timing 35U as indicated by a circle (5), the timing generation circuit 8b has a triangular wave. The configuration is such that the interval between the vertices of the signal 34 is the SW monitoring interval, and the PWM signal update timing signal 35U is not output when the PWM signal 36U changes from the apex of the triangular wave signal 34 until the output of the PWM signal update timing signal 35U. To do.

  According to the motor control device of the fourth embodiment, the result calculated by the current control unit can be immediately reflected as a PWM voltage command value without destroying the voltage balance of all phases applied to the motor. Can be increased. Furthermore, since the motor current is detected near the apex of the triangular wave signal, it is not easily affected by the switching of the semiconductor element. Furthermore, since the number of times of switching of the semiconductor element in the SW monitoring section is limited to one, the influence of noise and heat generation due to an increase in the number of times of switching of the semiconductor element does not increase. Furthermore, since the PWM voltage command value can be set up to the top of the triangular wave signal, the voltage utilization rate is not reduced.

  Example 5 will be described with reference to FIGS. The difference from the first embodiment is the configuration of the timing generation circuit 8c and the gate control unit 11b, which will be described. Although FIG. 10 shows an example of the U phase, the V phase and the W phase have the same configuration.

8 is a block diagram of the main part of the motor control device, FIG. 9 is a block diagram of the PWM inverter circuit,
FIG. 10 is an explanatory diagram of signal waveforms in each block. The timing generation circuit 8c of FIG. 8 outputs a PWM signal update timing signal A 35A to the PWM generator 3. The PWM signal update timing signal A 35A, when the PWM signal 36U is changed in the interval from the apex of the triangular wave signal 34 as shown in FIG. 10 until the output PWM signal update timing signal A 35A (round portion 4) Any signal The PWM generator 3 receives this signal and updates the PWM voltage command value 32U.

  The comparator 4 outputs a signal in which the PWM signal 36U changes a plurality of times during the SW monitoring period as shown in FIG. The timing generation circuit 8c monitors whether or not the PWM signal 36U has changed in the SW monitoring section between the vertices of the triangular wave signal 34. If the PWM signal 36U has not changed, the SW permission signal 37U is valid ( In the case of FIG. 10, H is output), and when changed, the SW permission signal 37U becomes invalid (in the case of FIG. 10, L is output).

  As shown in FIG. 9, the gate control unit 11b separates the PWM signal for three phases into an upper three phase and a lower three phase, and the gate control circuit 47b is turned on so as not to be turned on simultaneously when switching is switched. A period in which both are turned off with a delay is provided. Further, the SW permission signals 37U, 37V, and 37W from the timing generation circuit 8c are received, and when the SW permission signal is valid (H in FIG. 10), the switching of the PWM signals 39U, 39V, and 39W is permitted, and the SW permission is permitted. When the signal is invalid (L in FIG. 10), the switching is not permitted. FIG. 10 shows signal waveforms. When the SW permission signal 37U is H as in the circled point (4), the PWM signals 39U and 39X change in signal, and then the SW permission signal 37U becomes L and the PWM signals 39U and 39X do not change, and the next triangular wave signal The SW permission signal 37U becomes H at the apex of 34, and the change of the PWM signals 39U and 39X is permitted again.

  According to the motor control device of the fifth embodiment, the result calculated by the current control unit can be immediately reflected as the PWM voltage command value, so that the responsiveness of motor control can be improved. Furthermore, since the motor current is detected near the apex of the triangular wave signal, it is not easily affected by the switching of the semiconductor element. Furthermore, since the number of times of switching of the semiconductor element in the SW monitoring section is limited to one, the influence of noise and heat generation due to an increase in the number of times of switching of the semiconductor element does not increase. Furthermore, since the PWM voltage command value can be set up to the top of the triangular wave signal, the voltage utilization rate is not reduced.

FIG. 1 is a block diagram of a main part of a motor control device according to a first embodiment of the present invention. Block diagram of PWM inverter circuit and gate control unit of embodiment 1 Explanatory drawing of the signal waveform in each block of Example 1 Explanatory drawing of the signal waveform in each block of Example 2 Main part block diagram of motor control apparatus in embodiment 3 Explanatory drawing of the signal waveform in each block of Example 3 Explanatory drawing of the signal waveform in each block of Example 4 Main part block diagram of motor control apparatus in embodiment 5 Block diagram of PWM inverter circuit of embodiment 5 Explanatory drawing of the signal waveform in each block of Example 5 Main part block diagram of motor control device in conventional example Illustration of signal waveform in each block of conventional example (1) Illustration of signal waveform in each block of the conventional example (2) Illustration of signal waveform in each block of conventional example (3)

DESCRIPTION OF SYMBOLS 1 Current command 2 Current control part 3 PWM production | generation part 4 Comparator 5 PWM inverter circuit 6 Motor 7 Triangular wave generator 8a, 8b, 8c Timing generation circuit 9 Position sample hold circuit 11a, 11b Gate control part 12 Current detector 13 Position detection 14 Rotary encoder 15 Current sample hold circuit 16U, 16V Shunt resistor 31 (U, V, W) Each phase voltage command value 32 (U, V, W) Each phase PWM voltage command value 34 Triangular wave signal 35 (U, V) , W) PWM signal update timing signal for each phase
35A PWM signal update timing signal A
36 (U, V, W) Each phase PWM signal 37 (U, V, W) Each phase SW permission signal 38 Current sample hold timing signal 39 (U, V, W, X, Y, Z) Each phase gate signal 40 (U, V, W) Each phase output voltage 41 (U, V) Each phase motor current voltage conversion 42 (U, V) Each phase motor current digital data 43 (U, V) Each phase motor current sampling value 44 Rotor Position information 45 Rotor position detection value 46 Rotor position sampling value 47a, 47b Gate control circuit 48 Position sample hold timing signal 50 Power supply 51 Capacitor 52 (U, V, W, X, Y, Z) Each pre-drive circuit 53 (U, V, W, X, Y, Z) Each power element 54 (U, V, W, X, Y, Z) Each recovery diode

Claims (6)

A PWM inverter circuit that converts a DC voltage into an AC voltage by turning on and off the semiconductor element and supplies electric power to the motor;
A gate control unit for giving an ON / OFF command to the semiconductor element of the PWM inverter circuit;
A current detector for detecting a motor current value flowing through the motor ;
A current sample and hold circuit for holding the detected motor current value at a predetermined interval for digital calculation;
A triangular wave generator for generating a triangular wave signal having a PWM modulation period;
A current control unit that generates a voltage value to be applied to the motor;
A PWM generator that updates the voltage value generated by the current controller as a PWM voltage command value;
A comparator for outputting a PWM signal generated by comparing the magnitude of the PWM voltage command value and the triangular wave signal to the gate control unit;
The current sample-and-hold circuit holds the motor current value, a current sample-and-hold timing signal which the current control unit performs the digital operation, PWM signal update timing signal the PWM generation unit updates the PWM voltage command value and A timing generation circuit for generating
The current control unit performs a digital calculation time (current control calculation time) on both sides of the apex of the triangular wave signal,
The timing generation circuit includes:
Output the current sample hold timing signal immediately before the current control calculation time,
Monitor the change of the PWM signal from the comparator for each upper and lower vertex of the triangular wave signal,
When the PWM signal from the comparator does not change, the PWM signal update timing signal is generated immediately after the current control calculation time,
The motor control apparatus according to claim 1, wherein when the PWM signal from the comparator changes, the PWM signal update timing signal is generated at the next vertex of the triangular wave signal . A PWM inverter circuit that converts a DC voltage into an AC voltage by turning on and off the semiconductor element and supplies electric power to the motor;
A gate control unit for giving an ON / OFF command to the semiconductor element of the PWM inverter circuit;
A current detector for detecting a motor current value flowing through the motor ;
A current sample and hold circuit for holding the detected motor current value at a predetermined interval for digital calculation;
A triangular wave generator for generating a triangular wave signal having a PWM modulation period;
A current control unit that generates a voltage value to be applied to the motor;
A PWM generator that updates the voltage value generated by the current controller as a PWM voltage command value;
A comparator for outputting a PWM signal generated by comparing the magnitude of the PWM voltage command value and the triangular wave signal to the gate control unit;
The current sample-and-hold circuit holds the motor current value, a current sample-and-hold timing signal which the current control unit performs the digital operation, PWM signal update timing signal the PWM generation unit updates the PWM voltage command value and A timing generation circuit for generating
The current control unit performs a digital calculation time (current control calculation time) on both sides of the apex of the triangular wave signal,
The timing generation circuit includes:
Output the current sample hold timing signal immediately before the current control calculation time,
Monitor the change of the PWM signal from the comparator for each upper and lower vertex of the triangular wave signal,
When the PWM signal from the comparator does not change, the PWM signal update timing signal is generated immediately after the current control calculation time,
The motor control device according to claim 1, wherein the PWM signal update timing signal is not generated when the PWM signal from the comparator changes . Performed independently monitoring of the PWM signal from the comparator for each phase, the motor control device according to claim 1 or 2, wherein only be reflected in the generation of the PWM signal update timing signal in the monitored phase . The PWM signal from the comparator is monitored in all phases at once, and the PWM signal update timing signal for all phases is generated only when the output signals for all phases do not change, and the output signal changes for any phase 2. The motor control device according to claim 1 , wherein the PWM signal update timing signal for all phases is generated at the next vertex of the triangular wave signal . The PWM signal from the comparator is monitored in all phases at once, and the PWM signal update timing signal for all phases is generated only when the output signals for all phases do not change, and the output signal changes for any phase 3. The motor control device according to claim 2 , wherein the PWM signal update timing signal for all phases is not generated when the operation is performed . A PWM inverter circuit that converts a DC voltage into an AC voltage by turning on and off the semiconductor element and supplies electric power to the motor;
A gate control unit for giving an ON / OFF command to the semiconductor element of the PWM inverter circuit;
A current detector for detecting a motor current value flowing through the motor;
A current sample and hold circuit for holding the detected motor current value at a predetermined interval for digital calculation;
A triangular wave generator for generating a triangular wave signal having a PWM modulation period;
A current control unit that generates a voltage value to be applied to the motor;
A PWM generator that updates the voltage value generated by the current controller as a PWM voltage command value;
A comparator for outputting a PWM signal generated by comparing the magnitude of the PWM voltage command value and the triangular wave signal to the gate control unit;
A current sample / hold timing signal in which the current sample / hold circuit holds the motor current value, the current control unit performs the digital calculation, and a PWM signal update timing signal in which the PWM generation unit updates the PWM voltage command value; A timing generation circuit for generating
The current control unit performs a digital calculation time (current control calculation time) on both sides of the apex of the triangular wave signal,
The timing generation circuit includes:
Output the current sample hold timing signal immediately before the current control calculation time,
Generate the PWM signal update timing signal immediately after the current control calculation time,
By monitoring the change of the PWM signal from the comparator between the upper and lower vertices of the triangular wave signal, a switching permission signal for allowing the semiconductor element to be turned ON / OFF is generated,
It becomes effective by outputting a switching permission signal between the vertexes of the triangular wave signal and the next vertex until the PWM signal from the comparator changes, and the switching from the time when the PWM signal changes to the next vertex. It is invalidated without outputting a permission signal, switching is permitted when the switching permission signal is valid, and switching is not permitted when the switching permission signal is invalid, and the semiconductor element is not switched ON / OFF. A motor control device that outputs a valid or invalid signal of the switching permission signal to the gate control unit at every upper and lower vertices of the triangular wave signal .