JP4710474B2 - AC motor control device - Google Patents

Description

  The present invention relates to a technique for current feedback control of a plurality of AC motors by one digital arithmetic means.

A technique for performing current feedback control (vector control by current feedback control) on a plurality of AC motors with one digital arithmetic means (CPU) is disclosed in Patent Document 1 below.
In the above prior art, a method is described in which vector control of two electric motors (hereinafter referred to as motors) is performed by one CPU, the carrier periods of the two motors are made to coincide, and the vector control calculation period is set to the carrier period. The two motors are set to be an integer N times the same, and the vector calculation timings of the two motors are set so as not to overlap, and the N-time PWM output is calculated by performing respective angle correction calculations at the time of one vector calculation. A method of controlling is described.

JP 2002-272184 A

In the above prior art, the current feedback calculation means performs a heavy load current feedback calculation with a calculation cycle that is n times as long as a digital output cycle such as PWM, and at the same time, the calculation load is greatly reduced. By computing, the computation load can be distributed over time, and even if a microcomputer with lower processing power is used, the computation can be executed without breaking down, so the price of the microcomputer can be reduced. It has the effect of becoming. However, in the above-described conventional control device, the carrier cycle of the two motors is matched and the vector calculation timing is set so as not to overlap. Therefore, the PWM timer is set at the timing when the vector calculation timings of the two motors overlap. There is a problem that it cannot be driven by setting the phase difference.
In addition, since the carrier cycles of the two motors are matched and the vector calculation timing is set so as not to overlap, when one motor is driven with a lower carrier cycle, the calculation load of the CPU is There is a problem that even if possible, it is not possible to set different carrier periods.
The present invention has been made to solve the above-described problems. When a plurality of AC motors are vector-controlled by a single CPU, the calculation timing and carrier are suppressed while suppressing an increase in calculation load and control delay. It is an object of the present invention to provide a control device for an AC motor in which the degree of freedom in setting the cycle is improved.

In order to achieve the above object, in the present invention, when the rotation angle and the current value are read into the digital calculation means, and the current feedback control calculation is performed according to the read data, each of the plurality of AC motors Starts processing at the PWM timer valley interrupt set for the motor. “Reads the rotation angle and performs AD conversion processing of the current value (analog to digital conversion processing). Based on the read rotation angle and current value. “Process for performing current feedback control calculation” is performed as “Rotation angle and current data reading process” for reading rotation angle and AD conversion of current value, and “Calculation process for performing current feedback control calculation according to the read data” ”And separate interrupt processing, and the“ rotation angle and current data read processing ”is“ computed ” Than physical "set to a higher priority interrupt processing, and calculates the delay time to the time taken actually rotation angle and the current value from the interrupt point of the valley of the PWM timer, the rotation in accordance with the delay time The “calculation process” is performed based on values obtained by correcting the angle and the current value .

  With the above configuration, in the present invention, it is possible to accept the “rotation angle and current data reading process” for the other motor even while the “calculation process” for the one motor is being executed. Therefore, control is possible even if the relationship between the valley interrupts of the PWM timers of the two motors changes randomly. That is, the carrier frequency of each electric motor can be arbitrarily changed, and control can be performed even if the relationship between valley interrupts of the PWM timer changes randomly. Further, the control delay when processing requests of a plurality of electric motors overlap can be greatly reduced. Therefore, when performing vector control of a plurality of AC motors with a single CPU, it is possible to improve the degree of freedom in setting calculation timing and carrier period while suppressing increase in calculation load and control delay.

Embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a functional block diagram showing a vector control device of a three-phase synchronous motor configured to drive two motors A6 and B6 ′ (for example, a three-phase synchronous motor) with one CPU.
In FIG. 1, a portion surrounded by a broken line indicates a function in one CPU, and includes both the controller 100A of the motor A6 and the controller 100B of the motor B6 ′. Each block in the controllers 100A and 100B represents the control performed by the CPU as a functional block. Since the controllers 100A and 100B have the same configuration, the controller 100A will be described below.

  This control is a control in which the PWM cycle coincides with the vector control cycle. When the process is started by a valley interrupt of the PWM timer that generates the motor control PWM (interrupt at the PWM carrier signal valley = 0), Read the rotation angle (electrical angle) of the motor detected by the angle detector 10 (for example, resolver, encoder, etc.) and A / D convert the analog values iu, iv, iw of each phase current detected by the current sensor 7. The unit 8 converts the digital signal into three-phase current values Iu, Iv, and Iw and reads them.

Next, the three-phase to two-phase converter 9 calculates a d-axis current value Id and a q-axis current value Iq from the read three-phase current values Iu, Iv, and Iw and the rotation angle. Next, the current PI control unit 1 calculates a deviation between the d-axis current command value Id ^* and q-axis current command value Iq ^* given from the outside and the detected d-axis current value Id and q-axis current value Iq. The d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* are calculated from the deviation by well-known proportional integral control. Note that the d-axis current command value Id ^* and the q-axis current command value Iq ^* are values determined according to, for example, a torque command value (for example, a value corresponding to the opening degree of the accelerator pedal) and a rotation speed.

Next, the non-interference control unit 2 removes the dq-axis mutual interference component from the voltage command values Vd ^* and Vq ^* and performs the d-axis voltage command value Vd ^* ′ and the q-axis voltage command after the non-interference control. The value Vq ^* ′ is calculated. The rotation speed calculation unit 11 calculates the rotation speed of the motor from the rotation angle obtained by the angle detector 10, and the value is used for non-interference control in the non-interference control unit 2.

Next, the two-phase / three-phase converter 3 converts the voltage command values Vd ^* ′ and Vq ^* ′ after the non-interference control into three-phase voltage command values Vu ^* , Vv ^* and Vw ^* .
Next, the PWM conversion unit 4 converts the three-phase voltage command values Vu ^* , Vv ^* , and Vw ^* into a three-phase PWM signal by comparing with the carrier signal, and controls the inverter 5 with the PWM signal. As a result, the motor A6 is driven by supplying a three-phase alternating current. The current flowing through each phase of the motor A6 is detected by the current sensor 7.
The above processing is repeated to perform vector control by current feedback of the motor A6. The same process is performed for the motor B6 ′.

  In this way, when driving two motors with one CPU, in Patent Document 1, as shown in the timing diagram of FIG. 2, for example, a 32-bit microcomputer is used to perform a time of about 80 μs for one vector operation. If necessary, the carrier frequency of the two motors is 5 kHz (= carrier cycle 200 μs), the phase difference is 180 ° ((1) in FIG. 2), and the trough interrupt ((2) in FIG. 2) is It occurs alternately every 180 °, the calculation request ((3) in FIG. 2) does not overlap, the calculation actually performed ((4) in FIG. 2) has no delay, and the control is possible with a constant cycle. It was controlled by the condition. Note that the numbers (1), (2), (3), and (4) in “(1) of FIG. 2” and the like are indicated by circled numbers in the drawings (the same applies hereinafter).

FIG. 3 is a comparison diagram between the conventional control method as described above and the first embodiment of the present invention.
As shown in FIG. 3, conventionally, a single interrupt process started by a valley interrupt of a PWM timer that generates a motor control PWM performs “vector control calculation”, that is, “rotation angle reading and current value AD conversion processing. And processing for performing current feedback control calculation based on the read rotation angle and current value ”.

  On the other hand, in the first embodiment of the present invention, the interrupt processing described above is “rotation angle and current data reading processing” (hereinafter referred to as “data reading”) in which the rotation angle is read and the current value AD conversion is completed. (Abbreviated as “processing”) and “arithmetic processing” that performs current feedback control calculation according to the read data and separate interrupt processing, and “data reading processing” has priority over “arithmetic processing” It is configured to set high interrupt processing.

As a specific example, the timing diagram of FIG. 4 shows a case where the carrier frequency of two motors is 5 kHz (= carrier cycle 200 μs) and the phase difference is 90 ° ((1) in FIG. 4).
As shown in FIG. 4, the valley interrupt of the motor A6 always precedes ((2) in FIG. 4), and the valley interrupt of the motor B6 ′ is generated ((3) in FIG. 4) during the control calculation of the motor A6. Even in the case of a phase difference, since the priority of “data reading process” is set higher than “calculation process”, the valley of the motor B6 ′ generated during the control calculation of the motor A6 ((4) in FIG. 4). The interrupt ((3) in FIG. 4) is prioritized, the control calculation of the motor A6 is interrupted ((5) in FIG. 4), and the “data reading process” for capturing the current value and rotation angle of the motor B6 ′ is executed first. ((6) in FIG. 4).
Therefore, although the control operation is delayed, the “data reading process” (input data acquisition) that is equivalent to the control timing can be executed without delay in the discrete operation by the microcomputer, so that the control cycle can be controlled without delay. .

Next, as another specific example, FIG. 5 shows a case where the carrier frequency of two motors is 5 kHz (= carrier period 200 μs) and the phase difference is 0 °. When valley interrupts of motor A6 and motor B6 ′ overlap ((1) in FIG. 5), a time delay corresponding to one calculation of “vector calculation control” ((4) in FIG. 5) has conventionally occurred. On the other hand, by applying the present invention, the delay time is shortened to a delay of one time ((3) in FIG. 5) “data reading process” (FIG. 5 (5)) having the same priority level executed in order. It becomes possible. Furthermore, the effect of the delay can be further reduced by correcting the time delay when the data is actually read as described below.
That is, ideally, it is required to read the motor current value and the rotation angle at the moment of interruption at the valley (= 0) of the PWM timer. The PWM timer value ((5) in FIG. 5) at the time of capture is read, the delay time from the interrupt time is calculated, and the current value and the rotation angle are corrected according to the delay time. That's fine.

  As described above, as shown in FIG. 4 and FIG. 5, it is possible to control the valley interrupt of the PWM timers of the two motors without any problem if the “data read processing” does not overlap, and even when they overlap, it can be controlled almost without any problem. showed that. Therefore, by applying the present invention, control is possible regardless of the relationship between the valley interrupts of the PWM timers of the two motors. For example, the PWM period of the two motors is the same, and the phase difference is set to an arbitrary value. In addition, as shown in FIG. 6 to be described later, it is also possible to drive the two motors by arbitrarily varying the PWM cycle of the two motors.

  FIG. 6 shows that when the PWM periods of the two motors are not identical, that is, the carrier frequency of the motor A6 is 5 kHz (= carrier period 200 μs), and the carrier frequency of the motor B6 ′ is halfway from 4 kHz (= carrier period 250 μs). The timing chart in the case of changing to 3 kHz (= carrier cycle 333 μs) is shown.

As shown in FIG. 6, the valley interrupts of the PWM timers of the two motors are in a random relationship, but when the valley interrupts of the PWM timers of the motor A6 and the motor B6 ′ are close and the “data read processing” of each other overlaps ( In FIG. 6 (1)), control is performed with a slight delay (FIG. 6 (2)) corresponding to the overlap, and the PWM timer valley interrupt of the motor B6 ′ overlaps with the control calculation of the motor A6 (FIG. 6). (3)) is not delayed, and when the valley interrupt of the PWM timer of the motor A6 is independent ((4) in FIG. 6), the control is naturally performed without delay.
Thus, control is possible even if the relationship between the valley interrupts of the PWM timers of the two motors changes randomly. In other words, it can be seen that control can be performed even if the carrier frequency of each motor is arbitrarily changed and the relationship between valley interrupts of the PWM timer changes randomly.

Next, a second embodiment of the present invention will be described.
In this embodiment, the “data reading process” ((2) in FIG. 3) divided in the first embodiment is further divided. FIG. 7 shows the calculation contents in the second embodiment, and the upper part of FIG. 7 shows an enlarged view after the division of FIG. 3, and “data reading”, that is, “(1) in FIG. 7” = “ This is (2) in FIG.

  In the second embodiment, as shown in the lower part of FIG. 7, the “data reading process” ((1) in FIG. 7) is further divided into “rotation angle reading and current AD conversion start process”. ((2) in FIG. 7) and “AD conversion” ((3) in FIG. 7), and only “rotation angle reading and current AD conversion start processing” are obtained from “calculation processing” ((4) in FIG. 7). Is also a high-priority interrupt process. The above “AD conversion start” and “AD conversion” are AD conversions for the three-phase current detected by the current sensor 7.

  Since “AD conversion” is a process performed by the hardware of the microcomputer, during this time, “arithmetic processing” ((4) in FIG. 7) and “rotation angle reading and current AD conversion start processing” of the other motor can be executed. . Therefore, the delay time when the valley interrupts of the two motors are close to each other is reduced, the calculation time for driving one motor is shortened, and the calculation load of the microcomputer can be reduced.

  A specific example of the second embodiment is shown in FIG. FIG. 8 shows the same conditions as in FIG. 6, that is, the PWM periods of the two motors are not identical, the carrier frequency of the motor A6 is 5 kHz (= carrier period 200 μs), and the carrier frequency of the motor B6 ′ is 4 kHz (= carrier period 250 μs). FIG. 7 is a timing chart when the second embodiment is applied when the frequency is changed to 3 kHz (= carrier cycle 333 μs) in the middle of the operation.

As shown in FIG. 8, the valley interrupts of the PWM timers of the two motors are in a random relationship, but “high-priority interrupt processing“ rotation angle reading and current AD conversion start processing ”((2 in FIG. 7) )) Is short, the valley interrupt of the PWM timer of the motor B6 ′ overlaps with the “data reading process” of the motor A6 in FIG. 6 (1), whereas in FIG. Since the processing for the motor itself has been shortened, no overlap occurs.
As described above, in the second embodiment, the probability that the priorities are overlapped is reduced, and even if they are overlapped, the processing for one reading of “rotation angle reading and current AD conversion start processing” is short, so the delay time is shortened, Therefore, control performance can be improved.

Next, the third embodiment will be described in detail.
For example, when two motors are controlled by a CPU having only two AD converters, each motor uses two AD converters simultaneously to acquire two phases of three-phase currents. Two AD converters are used with a motor. Therefore, the other motor cannot be used while one motor is in use.

  The third embodiment corresponds to the above-described case, and as shown in FIG. 9, the process that starts at the valley of the PWM timer is changed to “if the calculation for the other motor is in use of the AD converter. The AD wait flag is set and the process is terminated. If not in use, the rotation angle reading and the current AD conversion start process are executed, and a calculation process interrupt request is started ”((1) in FIG. 9). In addition to the interrupt processing having a higher priority than the “arithmetic processing” ((2) in FIG. 9), the AD conversion end interrupt is set to “if there is an AD wait flag for the other motor, the AD for the other motor. As a process of “conversion start, process end if no flag is present” ((3) in FIG. 9), an interrupt process having the same priority as the process activated at the valley of the PWM timer is set.

FIG. 11 is a flowchart of an interrupt process that starts at the valley of the PWM timer, and FIG. 12 is a flowchart of an AD conversion end interrupt process.
In the interrupt process that starts at the valley of the PWM timer shown in FIG.
In step 1, it is determined whether or not the calculation for the other motor is in use of the AD converter. If it is in use, the process proceeds to step 5;
In step 2, the motor rotation angle is read and the process proceeds to step 3.
In step 3, AD conversion of current is started, and the process proceeds to step 4.
In step 4, an arithmetic processing interrupt is requested to end the processing,
In process step 5 in which the AD converter is being used, the AD conversion wait flag is set and the process is terminated.

In the AD conversion end interrupt process shown in FIG.
In step 1, it is determined whether or not there is an AD conversion waiting flag for the other motor, and if there is, the process proceeds to step 2, and if not, the process ends.
In step 2, the motor rotation angle of the other motor is read and the process proceeds to step 3.
In step 3, AD conversion of the current of the other motor is started, and the process proceeds to step 4.
In step 4, the processing interruption is requested for the other motor and the processing is terminated.

  As a result, a part of the “arithmetic processing” ((2) in FIG. 9) is performed at the other AD conversion end waiting time that occurs at the timing when the “rotation angle reading and current AD conversion start processing” of each motor overlap. Execution is possible, and an increase in computation load due to prolonged control time can be prevented.

FIG. 10 shows a specific example in the third embodiment, in which the PWM period of the two motors is set such that both the motor A6 and the motor 6B ′ have a carrier frequency of 5 kHz (= carrier period 200 μs) and a phase difference of 0 °. FIG. 6 is a timing diagram when the third embodiment is applied.
The valley interrupts of the PWM timers of the motor A6 and the motor B6 ′ are always generated simultaneously ((9) in FIG. 10). For example, when the interrupt of the motor A6 is processed first, the PWM timer of the motor A6 is first described. After confirming that “α: Rotation angle reading of motor A6 & start of current AD ((1) in FIG. 10)” is activated and “current AD” of motor B6 ′ is not activated by the valley interrupt. Then, “rotation angle reading & current AD start” is executed, an interrupt of “C: calculation processing of motor A6” ((3) in FIG. 10) is requested, and the processing is completed.

  Next, “β: Read rotation angle of motor B6 ′ and start current AD” ((2) in FIG. 10) already requested by the PWM timer valley interrupt of motor B6 ′ is started. Since “current AD” is activated, the processing is not performed, and the current reading waiting flag of the motor B 6 ′ is set and the processing ends.

Next, the “C: Calculation processing of motor A6” interrupt ((3) in FIG. 10) requested in “α: Reading rotation angle of motor A6 & starting current AD” ((1) in FIG. 10) is activated. In the middle of the calculation, “γ: AD conversion of motor A6” ((4) in FIG. 10) ends, and “αii: current AD completion interrupt of motor A6” ((5) in FIG. 10). Starts.
In “αii: current AD completion interrupt of motor A6” ((5) in FIG. 10), the current reading wait flag of motor B6 ′ is checked, and if it is not waited, the process ends without doing anything. Therefore, the motor B6 ′ immediately starts the “read rotation angle read current AD”, requests an interruption of “D: B6 ′ calculation processing of the motor” ((7) in FIG. 10), and completes the processing. . Then, “C: control calculation of motor A6” ((3) in FIG. 10), which was interrupted, is resumed.

However, on the way, “δ: AD conversion of motor B 6 ′” ((8) in FIG. 10) is completed, and “β ii: current AD completion interrupt of motor B 6 ′” ((6) in FIG. 10) is activated. To do.
In “βii: current AD completion interrupt of motor B6 ′” ((6) in FIG. 10), the current read waiting flag of motor A6 is checked. If it is not waiting, it is terminated without doing anything. Starts the “read rotation angle read current AD” of the motor A6, requests the interruption of “C: arithmetic processing of the motor A6” ((3) in FIG. 10), and completes the process, but this time has already ended. Because it does, it ends without doing anything.
Then, “C: control calculation of the motor A6” ((3) in FIG. 10), which has been interrupted again, is resumed, and the calculation processing of the motor A6 is completed.

Next, the interrupt “D: Calculation processing of motor B6 ′” ((7) in FIG. 10) requested in “αii: Current AD completion interrupt of motor A6” ((5) in FIG. 10) is activated. The control calculation of the motor B6 ′ is executed, and the process is completed.
As described above, the control calculation of the two motors generated simultaneously is completed.
FIG. 13 is an enlarged view of a portion surrounded by a broken-line circle in FIG.

Next, the fourth embodiment will be described in detail.
In the first to third embodiments described so far, the motor A6 and the motor B6 ′ are equal, but in the fourth embodiment, for example, the motor L and the priority that have a high priority in terms of control performance. This is to preferentially control the motor L by preferentially performing the “data fetching process” of the motor L having a high priority when the low-speed motor M is simultaneously controlled by one CPU.

14 shows a case where the fourth embodiment is combined with the first embodiment, FIG. 15 shows a case where the fourth embodiment is combined with the second embodiment, and FIG. 16 shows a case where the fourth embodiment is combined with the third embodiment. It is a figure which shows the priority at the time of combining an Example.
In either case, “data read” of the motor L has a higher priority than that of the motor M, and if the “data read” process of the motor L is requested during the “data read” process of the motor M, it is executed immediately. Thereafter, the process of the motor M is executed.
Although the control of the motor M having a low priority is delayed as described above, the control of the motor L having a high priority can always be executed with priority.

  In the description so far, the case where two motors are controlled by one CPU has been exemplified, but three or more motors can be controlled by the same concept. However, there is a possibility that the calculation delay when the control overlaps becomes larger as the number of motors is larger.

  As described above, in the present invention, “the rotation angle reading and current value AD conversion processing are performed in the conventional vector control calculation, and the current feedback control calculation is performed based on the read rotation angle and current value. "Process to perform" is divided into "Rotation angle and current data reading process" that performs reading of rotation angle and AD conversion of current value, and "Calculation process" that performs current feedback control calculation according to the read data Separate interrupt processing, and "rotation angle and current data read processing" is set to interrupt processing with higher priority than "computation processing". ”Can be received while the“ rotational angle and current data reading process ”for the other motor is being executed. Therefore, control is possible even if the relationship between the valley interrupts of the PWM timers of the two motors changes randomly. In other words, the carrier frequency of each motor can be arbitrarily changed, and control can be performed even if the relationship between valley interrupts of the PWM timer changes randomly. Further, the control delay when processing requests of a plurality of motors overlap can be greatly reduced. Therefore, when performing vector control of a plurality of AC motors with a single CPU, it is possible to improve the degree of freedom in setting calculation timing and carrier period while suppressing increase in calculation load and control delay.

  In addition, when the interrupt processing of “rotation angle and current data reading processing” is configured to be only the interrupt processing of “rotation angle reading and current AD conversion start processing”, it takes precedence over “calculation processing”. By shortening the high-level interrupt processing only as “loading rotation angle and starting current AD conversion”, the delay time when processing requests from multiple motors overlap can be reduced. Since part of the “arithmetic processing” can be executed, the computational load on the CPU can be reduced.

  Also, the process that starts at the valley of the PWM timer is set to “If the calculation for the other motor is in use of the AD converter, the AD wait flag is set and the process is terminated. Execute the conversion start process and activate the arithmetic process interrupt request "and set the interrupt process to have a higher priority than the" arithmetic process ", and set the" current AD conversion end interrupt "to" the AD of the other motor " If it is configured to perform interrupt processing with the same priority as the processing that starts at the valley of the PWM timer as the processing of “AD conversion start for the other motor if there is a wait flag, processing end if there is no flag” When controlling a plurality of motors using a microcomputer that does not have enough AD converters for the number of motors to be shared, the AD converters are shared. If the motor processing overlaps, even if one AD conversion process waits for the other AD conversion process to end, the wait flag is set and the high priority process ends. A part of “calculation processing” with low priority can be executed, and the current control calculation time can be prevented from being prolonged.

  Also, priorities are assigned to a plurality of motors, and the “rotation angle and current data reading process” or “rotation angle reading and current AD conversion start process” or “current AD conversion end interrupt” is prioritized for each motor. In a case where a difference is provided in the priority according to the order, a motor having a high importance can be preferentially controlled by assigning a priority according to the importance of the motor to be controlled.

  Also, when the delay time from the interrupt time at the PWM timer valley to the time when the rotation angle and current value are actually taken is calculated, and the rotation angle and current value are corrected according to the delay time In other words, by correcting when a rotation angle reading delay occurs, an error in the estimated rotation angle calculation accuracy at the time of output calculation can be prevented, and deterioration of the control performance can be prevented.

It is a figure which shows the vector control apparatus to which this invention is applied, and is a functional block diagram which shows the vector control apparatus of the three-phase synchronous motor comprised so that two motors might be driven by one CPU. The motor control timing diagram in patent document 1. FIG. The figure which shows the division | segmentation method of the interruption of the vector control calculation in 1st Example of this invention. The control timing diagram of the 1st example in the 1st example of the present invention. The control timing diagram of the 2nd example in the 1st example of the present invention. The control timing diagram of the 3rd example in the 1st example of the present invention. The figure which shows the division | segmentation method of the interruption of the vector control calculation in 2nd Example of this invention. The control timing diagram of the specific example in the 2nd Example of this invention. The figure which shows the division | segmentation method of the interruption of the vector control calculation in 3rd Example of this invention. The control timing diagram of the specific example in the 3rd Example of this invention. The flowchart of the interruption process started at the valley of the PWM timer in the 3rd example of the present invention. Flowchart of AD conversion end interrupt processing in the third embodiment of the present invention FIG. 11 is an enlarged view of a portion surrounded by a broken-line circle in FIG. 10. The figure which shows the division | segmentation method and priority in the case of combining a 4th Example with a 1st Example. The figure which shows the division | segmentation method and priority in the case of combining a 4th Example with a 2nd Example. The figure which shows the division | segmentation method and priority in the case of combining a 4th Example with a 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 '... Current PI control part 2, 2' ... Non-interference control part 3, 3 '... Two-phase three-phase conversion part 4, 4' ... PWM conversion part 5, 5 '... Inverter 6, 6' ... Motor A , Motor B
7, 7 '... Current sensor 8, 8' ... A / D converter 9, 9 '... Three-phase two-phase converter 10, 10' ... Angle detector 11, 11 '... Rotational speed calculator 100A, 100B ... Controller

Claims (4)

In an AC motor control apparatus that performs current feedback control of a plurality of AC motors in common using one digital arithmetic means,
The rotation angle detected by the rotation angle detection means for detecting the rotation angle of the AC motor and the current detection means for detecting the current flowing in each phase of the AC motor are read into the digital calculation means, and the read data is read. When performing current feedback control calculation according to
The processing is started by a valley interrupt of a PWM timer set corresponding to each of the plurality of AC motors. “Reading rotation angle and AD conversion processing of current value are performed, and the read rotation angle and current value are set. "Process for performing current feedback control calculation based on", "Rotation angle and current data reading process" for performing reading of rotation angle and completion of AD conversion of current value, and performing current feedback control calculation according to the read data " It is divided into `` arithmetic processing '' and separate interrupt processing, and the `` rotation angle and current data reading processing '' is set to interrupt processing with higher priority than the `` arithmetic processing '' ,
The delay time from the interrupt point at the PWM timer valley to the time when the rotation angle and the current value are actually taken is calculated, and the “calculation” is calculated based on the value obtained by correcting the rotation angle and the current value according to the delay time. A control device for an AC motor characterized in that the processing is performed . 2. The AC motor control device according to claim 1, wherein the interruption process of the “rotation angle and current data reading process” is an interruption process of only “a rotation angle reading and a current AD conversion start process”. AC motor control device. In the control apparatus for an AC motor according to claim 1 or 2,
When not having enough AD converters for the number of AC motors controlled by the digital calculation means and controlling the AD converters shared by the AC motors, the process of starting at the valley of the PWM timer is If the calculation for the motor is using the AD converter, the AD wait flag is set and the process is terminated. If not, the rotation angle is read and the current AD conversion start process is executed, and the calculation process interrupt request is activated. Interrupt processing having a higher priority than "arithmetic processing", and the "current AD conversion end interrupt" is set to "start AD conversion for the other motor if there is an AD wait flag for the other motor" The control apparatus for an AC motor is characterized in that an interrupt process having the same priority as that of the process activated at the valley of the PWM timer is performed as a process “end if no flag is present”. In the control apparatus of the alternating current motor according to any one of claims 1 to 3,
Priorities are assigned to a plurality of AC motors, "Rotation angle and current data reading process" in claim 1 or "Rotation angle reading and current AD conversion start process" in claim 2 or "Current AD conversion" in claim 3. A control device for an AC motor, characterized in that a difference in priority is provided for each AC motor in accordance with the priority order for "end interrupt".

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