JP2005030787A - Rotator rotation angle detection device for permanent magnet synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotator rotation angle detection device of a permanent magnet synchronous motor capable of detecting the rotation angle of the rotator even when the number of one rotation output pulses of an encoder exceeds the maximum value of an encoder pulse counter. <P>SOLUTION: This rotator rotation angle detection device for the permanent magnet synchronous motor is equipped with the encoder pulse counter 13 for counting the number of output pulses of a rotary encoder 12 connected to the rotator of the permanent magnet synchronous motor 11 and outputting the counted value, a Z-phase signal detection device 14 for detecting a Z-phase signal outputted in each one rotation of the rotary encoder 12, a counter latch device 15 for storing the counted value at a timing when the Z-phase signal is generated, an operation device 16 for operating a deviation of the counted values at a prescribed operation cycle and operating the accumulated value of the deviation of the counted values by using the counted value stored in the counter latch device 15 as a reference value, and a storage device 17 for storing the accumulated value of the deviation of the counted values. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotor rotation angle detection device for a permanent magnet synchronous motor, and more particularly to a rotor rotation angle detection device for a permanent magnet synchronous motor used in applications such as an elevator drive motor.
[0002]
[Prior art]
When controlling a permanent magnet synchronous motor having a stator and a rotor, it is necessary to detect the rotation angle of the rotor relative to the stator. Generally, the rotor rotation angle detection of a permanent magnet synchronous motor detects an encoder connected to the rotor and a Z-phase signal indicating a reference position of the encoder output from a sensor provided at a predetermined position of the encoder. This is performed using a Z-phase detection circuit and a rotation amount calculation circuit that counts the number of output pulses from the encoder by a counter and outputs a count value. The count value of the rotation amount calculation circuit is reset every time the Z-phase detection circuit receives the Z-phase signal and becomes 0 (zero). Therefore, the rotor based on the Z-phase is determined by the count value of the number of output pulses. Can be calculated (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-145552
[Problems to be solved by the invention]
In this type of conventional motor rotor rotation angle detection device, if the number of output pulses per rotation of the encoder exceeds the maximum value of the counter, the count value of the encoder pulse counter overflows. Since the rotation angle of the rotor cannot be uniquely determined, the number of pulses generated by one rotation of the encoder must be set so as not to exceed the maximum value of the encoder pulse counter. If it is large, there is a restriction that a large encoder pulse counter must be used.
[0005]
The present invention has been made to solve such problems, and a permanent magnet capable of detecting the rotation angle of the rotor even when the number of output pulses per rotation of the encoder exceeds the maximum value of the encoder pulse counter. An object of the present invention is to obtain a rotor rotation angle detection device for a synchronous motor.
[0006]
[Means for Solving the Problems]
The present invention relates to a rotary encoder connected to a rotor of a permanent magnet synchronous motor, an encoder pulse counter that counts the number of output pulses of the rotary encoder and outputs a count value, and outputs each time the rotary encoder makes one rotation. Z-phase signal detection means for detecting the Z-phase signal to be generated, counter latch means for storing the count value at the timing when the Z-phase signal is generated, and deviation calculation for calculating the deviation of the count value at a predetermined calculation cycle Rotation of a permanent magnet synchronous motor comprising: means; and cumulative value calculation means for calculating a cumulative value deviation of the count value calculated by the deviation calculation means, using the count value stored in the counter latch means as a reference value This is a child rotation angle detection device.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a diagram showing an overall configuration of a rotor rotation angle detection device for a permanent magnet synchronous motor according to Embodiment 1 of the present invention. As shown in FIG. 1, the rotor rotation angle detection device for a permanent magnet synchronous motor according to the present embodiment includes a rotary encoder 12 connected to a rotor (not shown) of the permanent magnet synchronous motor 11, and a rotary encoder 12. An encoder pulse counter 13 that counts the number of pulses output from the encoder encoder 13 and outputs an encoder pulse count value ENC1 and a sensor (not shown) at a predetermined position of the rotary encoder 12 are provided so that the rotary encoder 12 rotates once. A Z-phase signal indicating the reference position of the rotary encoder 12 output from the sensor is detected every time, and the value of the Z-phase signal generation detection flag is changed from “Z-phase signal generation not detected (for example,“ 0 ”)” to “Z-phase”. The Z-phase signal detection device 14 for signal generation detection (for example, “1”) and the timing of detection of the Z-phase signal The counter latch device 15 for storing the coder pulse count value ZENC, and the deviation of the count value obtained by subtracting the encoder pulse count value ZENC stored in the counter latch device 15 from the encoder pulse count value ENC1 output from the encoder pulse counter 13, or The deviation ENCD1 of the count value obtained by subtracting the encoder pulse count value ENC2 of the previous calculation cycle from the encoder pulse count value ENC1 output from the encoder pulse counter 13, the correction value ENCD2 of the deviation, and the accumulated value ENCT of the deviation are calculated. For storing the arithmetic unit 16 that performs the calculation, the deviation ENCD1 of the count value obtained by the arithmetic unit 16, the correction value ENCD2 of the deviation, the cumulative value ENCT, and the encoder pulse count value ENC2 of the previous arithmetic cycle. Composed from the device 17.
[0008]
The operation will be described. FIG. 2 shows a process flow of the rotor rotation angle detection device according to the present embodiment. In this embodiment, the rotary encoder 12 has 200,000 output pulses per rotation, the maximum pulse counter value of the encoder pulse counter 13 is 65,535 pulses, and the rotary encoder 12 rotates in the forward direction. I will give you a description. As shown in FIG. 3, when the count value (symbol 30) reaches the maximum value of the pulse counter (symbol 31) (here, 65,535 pulses), the encoder pulse counter 13 causes an overflow and automatically “0”. Since the count value is reset to (zero) ", the output count value is plotted in a sawtooth shape shown in FIG. That is, for example, when the count value is 70,000 pulses, an overflow occurs at the time of the maximum value of the pulse counter (reference numeral 31) (65,535 pulses) and is reset to 0 (zero). The value is 70,000−65,535 = 4,465 pulses, and an error of 65,536 pulses has occurred. Further, as shown in FIG. 3, when the encoder output value (symbol 32) reaches the encoder output maximum value (symbol 33) (here, 200,000 pulses), that is, when the rotary encoder 12 makes one rotation, (Zero) ”is reset.
[0009]
As shown in FIG. 2, first, in step S <b> 1, the arithmetic unit 16 obtains the encoder pulse count value ENC <b> 1 of the current arithmetic cycle from the encoder pulse counter 13 at a predetermined arithmetic cycle, and the previous arithmetic cycle from the storage device 17. The encoder pulse count value ENC2 is taken out, the encoder pulse count value ENC2 in the previous calculation cycle is subtracted from the encoder pulse count value ENC1 in the current calculation cycle, and the result is stored in the storage device 17 as the deviation ENCD1 of the count value. In step S2, it is determined whether or not the absolute value of the deviation ENCD1 of the count value stored in step S1 exceeds 60,000. The value “60,000” is a predetermined threshold value set in advance, but is not limited to this value, and is appropriately set to a predetermined value less than the maximum value (65,535 pulses) of the encoder pulse counter 13. To do. If it does not exceed 60,000, the deviation ENCD1 of the count value is stored in the storage device 17 as ENCD2 in step S3. On the other hand, if it exceeds 60,000 as determined in step S2, 65,535 pulses which are the maximum value of the encoder pulse counter 13 are added to the deviation ENCD1 of the count value in step S4. It is corrected and stored in the storage device 17 as ENCD2. This is a process of correcting 65,536 errors in the deviation ENCD1 of the count value calculated in step S1 as described above due to overflow of the encoder pulse counter 13. Since the absolute value of the deviation does not exceed 60,000 at the rotational speed of the normal rotary encoder 12, if the absolute value of the deviation exceeds 60,000, it can be considered that the encoder pulse counter 13 has overflowed. .
[0010]
Next, in step S5, it is determined whether the Z-phase signal generation detection flag of the Z-phase signal detection device 14 is in the “Z-phase signal generation detection” state. That is, it is determined whether or not a Z-phase signal has been detected during the current calculation cycle. If it is in the “Z phase signal generation not detected” state, in step S6, the value of ENCD2 obtained in step S4 or S5 is added to the accumulated value ENCT of the deviation of the previous calculation cycle and stored as a new accumulated value ENCT. . On the other hand, if it is determined in step S5 that the state is “detection of Z phase signal generation”, the counter latch device 15 obtains the encoder pulse count value ENC1 in the current calculation cycle from the encoder pulse counter 16 in step S7. The value obtained by subtracting the encoder pulse count value ZENC (reference numeral 35 in FIG. 3) latched at the timing at which the detected Z-phase signal is detected (reference numeral 34 in FIG. 3) is stored as the accumulated value ENCT of the deviation of the counter output. This is because the counter output deviation accumulated value ENCT is reset to zero at the Z-phase signal detection timing, and the number of pulses generated between the Z-phase signal detection timing and the current calculation cycle is set to the initial value of ENCT. It is processing to. Finally, in step S8, the value of ENC1 is stored in ENC2 for the calculation of the next calculation cycle.
[0011]
As described above, the accumulated value ENCT returns to zero when the rotary encoder 12 changes to the same value as the number of pulses generated in one rotation, and also returns to zero when the Z-phase signal is generated. 1 rotation of the rotary encoder 12 from 1 corresponds to a change in the accumulated value ENCT of the deviation of the counter output from 0 (zero) until it exceeds 19999999 and returns to zero again. The rotation angle of the child can be detected.
[0012]
According to the present embodiment, the rotation angle of the rotor is accurately detected even when the number of output pulses per rotation of the rotary encoder connected to the rotor of the permanent magnet synchronous motor exceeds the maximum value of the encoder pulse counter. be able to. As described above, in this embodiment, the high-resolution rotary encoder is not subject to the restriction that the number of generated pulses per rotation of the rotary encoder 12 must be a combination that does not exceed the maximum value of the encoder pulse counter. It can be applied to control of a permanent magnet synchronous motor.
[0013]
That is, using an encoder pulse counter capable of counting pulses generated during one rotation of the electric motor, that is, one rotation of the rotary encoder 12, results in a large-scale counter and is expensive. Therefore, in the present embodiment, it is noted that the number of pulses generated in one calculation cycle has a limit value even if the motor is rotated at the maximum speed by appropriately setting the calculation cycle of the calculation device 16. Thus, the maximum pulse counter value of the encoder pulse counter can be reduced, and the encoder pulse counter can be miniaturized.
[0014]
As a result, the entire rotor rotation angle detection device of the permanent magnet synchronous motor of the present invention can be miniaturized. For example, when the detection device of the present invention is used to detect the rotation angle of the rotor of an elevator drive motor. It is particularly effective because it is easy to place in a narrow hoistway of an elevator.
[0015]
【The invention's effect】
The present invention relates to a rotary encoder connected to a rotor of a permanent magnet synchronous motor, an encoder pulse counter that counts the number of output pulses of the rotary encoder and outputs a count value, and outputs each time the rotary encoder makes one rotation. Z-phase signal detection means for detecting the Z-phase signal to be generated, counter latch means for storing the count value at the timing when the Z-phase signal is generated, and deviation calculation for calculating the deviation of the count value at a predetermined calculation cycle Rotation of a permanent magnet synchronous motor comprising: means; and cumulative value calculation means for calculating a cumulative value deviation of the count value calculated by the deviation calculation means, using the count value stored in the counter latch means as a reference value Since this is a slave rotation angle detector, the number of output pulses per revolution of the encoder is Even if it exceeds a large value, it is possible to detect the rotation angle of the rotor.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a configuration of a rotor rotation angle detection device for a permanent magnet synchronous motor according to Embodiment 1 of the present invention;
FIG. 2 is a flowchart showing a processing flow of a rotor rotation angle detection device for a permanent magnet synchronous motor according to Embodiment 1 of the present invention;
FIG. 3 is an explanatory diagram showing the operation of the rotor rotation angle detection device for a permanent magnet synchronous motor according to Embodiment 1 of the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Permanent magnet synchronous motor, 12 Rotary encoder, 13 Encoder pulse counter, 14 Z phase signal detection apparatus, 15 Counter latch apparatus, 16 Arithmetic apparatus, 17 Memory | storage device.

Claims (4)

A rotary encoder connected to the rotor of the permanent magnet synchronous motor;
An encoder pulse counter that counts the number of output pulses of the rotary encoder and outputs a count value;
Z-phase signal detection means for detecting a Z-phase signal output each time the rotary encoder makes one rotation;
Counter latch means for storing the count value at the timing when the Z-phase signal is generated;
Deviation calculation means for calculating the deviation of the count value at a predetermined calculation cycle;
A permanent magnet synchronous motor comprising: cumulative value calculation means for calculating a cumulative value of the deviation of the count value calculated by the deviation calculation means using the count value stored by the counter latch means as a reference value Rotor angle detector. A rotary encoder connected to the rotor of the permanent magnet synchronous motor;
An encoder pulse counter that counts the number of output pulses of the rotary encoder and outputs a count value, and that resets the count value when the count value reaches a preset maximum value;
Pre-count value storage means for storing the count value by the encoder pulse counter in the pre-calculation cycle;
Deviation calculation means for calculating the deviation of the count value by subtracting the count value stored in the previous count value storage means from the count value by the encoder pulse counter in the current calculation cycle;
When the deviation of the count value by the deviation calculating means is less than a predetermined threshold value smaller than the maximum value of the encoder pulse counter, the deviation is output as it is, and when the deviation is larger than the threshold value, the deviation is output. Deviation correction means for outputting a value obtained by adding the maximum value to
Z-phase signal detection means for detecting a Z-phase signal output each time the rotary encoder makes one rotation;
Counter latch means for storing the count value at the timing when the Z-phase signal is generated;
It is determined whether or not the Z-phase signal is detected by the Z-phase signal detection means during the current calculation cycle. If there is a detection, the counter latch is determined from the count value by the encoder pulse counter in the current calculation cycle. The value obtained by subtracting the count value stored in the means is output as the accumulated value of the deviation of the count value. If there is no such detection, the previous calculation is performed from the time when the previous Z-phase signal was detected. A cumulative value calculation means for adding the deviation output from the deviation correction means to a cumulative value of the deviation of the count value up to a cycle and outputting the cumulative value of the deviation of the count value;
Cumulative value storage means for storing a cumulative value of deviation of the count value by the cumulative value calculation means;
A permanent magnet synchronous motor comprising: count value update means for updating the count value in the previous calculation cycle stored in the previous count value storage means using the count value in the current calculation cycle Rotor rotation angle detection device. The accumulated value of the deviation of the count value of the accumulated value calculating means is reset when reaching the same value as the number of output pulses of one rotation of the rotary encoder. A rotor rotation angle detection device for a permanent magnet synchronous motor. 3. The permanent magnet according to claim 1, wherein the cumulative value of the deviation of the count value of the cumulative value calculating means is reset at a timing when the Z-phase signal detecting means detects the Z-phase signal. A rotor rotation angle detection device for a synchronous motor.

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