JPH0646876B2 - Synchronous control device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a synchronous control device for synchronously operating two machines driven by an induction motor via an inverter device.

[Conventional technology]

2. Description of the Related Art As a conventional synchronous control device of this type, one illustrated in the control block diagram of FIG. 2 is known. FIG. 3 is an output waveform and relative positional relationship diagram of the synchro electric machine in FIG. In FIG. 2, 1a and 1b are 2a and 2 respectively.
It is a machine that is driven by an induction motor with b and is operated synchronously. In the case shown, 1a is a preceding machine and 1b is a follower machine. Two
Reference numerals 0a and 20b denote synchro electric machines which are connected to the machines 1a and 1b and are rotationally driven, respectively.
0a is a transmitter and 20b is a receiver, and pair with each other. A sine wave voltage corresponding to the difference in relative angle between the stator and the rotor of each of the transmitter and receiver is output to the stator side of the receiver 20b. Reference numeral 21 is a displacement detection circuit that receives the sine wave output voltage and determines the magnitude and polarity of the rotation angle difference between the transmitter and receiver rotors. Reference numeral 22 is an electric motor drive circuit that controls the follower electric motor 2b so as to make the rotational angle difference between the rotors zero by receiving the output of the detection circuit. Still, FIG. 3 (a) shows the waveform of the sine wave output voltage, and FIG. 3 (b) corresponds to the horizontal axis phase angle of the output voltage, that is, the rotation angle difference, and is based on the transmitter rotor position. The relative relationship of the said receiver rotor position in a case is shown.

[Problems to be Solved by the Invention]

However, in the above-mentioned conventional method, the output voltage of the synchro receiver for detecting the positional deviation between the preceding and following units changes sinusoidally, and the phase angle θ of the sine wave is 2π (ra).
d) It is not possible to discriminate position deviations corresponding to above and below, and therefore it is necessary to provide n detection means for discriminating between sin θ and sin (2πn + θ) with respect to the integer n, or to perform an operation that always satisfies 0 ≦ θ <2π. Become. For this reason, simultaneous start-up of the preceding and following follow-up machines after the start-up points are aligned, operation of the machines such as coupling of the origin coincidence with both machines and the like, or complication of the control circuit is caused. In view of this, the present invention is
It is an object of the present invention to provide a synchronous control device that solves the above problems by calculating a coefficient of a rotary encoder output pulse.

[Means for Solving the Problems]

As the set speed of the inverter for controlling the following machine, the preceding machine speed, the speed difference between the preceding machine and the following machine, the required correction amount of the phase difference angle between the origins of the encoders driven by the both machines, and the correction amount. Various means are provided for calculating the sum of the three differences in the temporal tracking angle amount with respect to. That is, in the synchronous control device for the two machines, one of the two machines driven by the induction motor is a preceding machine, and the other is a follower for the preceding machine to perform follow-up synchronous operation.
A two-phase pulse signal of A-phase and B-phase, which are respectively coupled to the two machines and rotate and have a phase difference of 90 degrees depending on the rotation speed, and an origin signal of one pulse for each rotation, that is, Two sets of encoders that output a Z-phase signal, and two sets of frequency doublers that output a quadruple frequency pulse signal of the two-phase pulse signals of both encoders and determine the rotation direction of each corresponding encoder. A direction discriminating circuit, two sets of speed detecting circuits for calculating the rotational speed of the corresponding encoder from the A-phase or B-phase pulse signal of each of the encoders, and Z of each of the encoders.
A phase difference detection circuit for calculating the phase difference angle between the origins of the two encoders at the start of synchronous control for the follower by using a phase pulse signal and the quadruple frequency pulse signal corresponding to the encoder of the preceding machine, and the two encoders Deviation counter circuit for calculating the difference between the integrated values of the quadruple frequency pulse signals corresponding to the above, including the sign, and subtracting the integrated value difference from the output value of the phase difference detection circuit given as an initial set value. A first addition / subtraction calculator for calculating an output difference between the two speed detection circuits, an output of the speed detection circuit corresponding to the preceding machine, an output of the deviation counter circuit, and an output of the first addition / subtraction calculator. A second adder / subtractor calculator for calculating the sum of the two and two sets of inverter devices for controlling the speeds of the induction motors respectively, and the follow-up is performed by using the output of the second adder / subtractor calculator. It is characterized in that formed between the set speed signal of the induction motor speed control inverter device.

[Action]

Generally, in the synchronous operation of two machines, it is necessary to make the moving parts to be synchronized of both the machines uniform in speed and to match required specific positions in both the moving parts. Therefore, if both machines are ordered as a preceding machine and a follower machine to be synchronized with the preceding machine, the synchronous control of the two machines will be performed at a constant speed with the preceding machine by appropriate acceleration / deceleration control for the follower machine. Two types of control are provided, namely, the generalization control and the control for making the required specific position deviation between the preceding and following machines zero. The present invention is directed to a case where an induction motor is used as a drive source for both the machines, and the two motors are respectively controlled by an inverter to perform variable speed control for synchronous control, and the speed set value of the follower machine control inverter is set to the preceding value. Speed detection value of the following machine, the speed detection value difference between the preceding and following machines, and the required specific position deviation between the two machines, which is the sum of the three, and the following control of the speed and position both sides of the following machine with respect to the preceding machine Is performed so that the speed difference term and the position deviation term in the speed set value are both controlled to be zero. The speed difference term and the position difference term are added to the inverter via a proportional / integral (PI) adjuster so as to be input to the electric motor speed control system with optimum time characteristics. Here, the position deviation term is a position tracking for the reference position deviation that increases the temporal integrated value according to the reference position deviation of each of the preceding tracking machines and the speed difference between the preceding tracking machines at the time of starting the synchronous control for the follower. It is the difference from the correction value and is a term that changes with time. Further, in the present invention, the determination of the speed and position specifications is output from each of the two sets of encoders that are rotationally driven by being coupled with the two machines in a specific positional relationship, for each specified rotation angle of each encoder. From the two-phase pulse signals of the A phase and the B phase, which are generated with a phase difference of 90 degrees from each other, and the reference origin signal, that is, the Z phase pulse signal and the two phase pulse signal, which are emitted at a rate of one pulse for each rotation of each encoder. The calculation is performed by various digital operations with the quadruple frequency pulse signal of the combined operation signal. That is, the speed is detected by a speed detection circuit that compares the A-phase or B-phase pulse signal period with a clock signal, and the position-to-position deviation is included in the time difference between the Z-phase pulse signals generated by both encoders. The phase difference detection circuit for counting the number of quadruple frequency pulses by the preceding machine encoder is detected as the number of angle-corresponding pulses. Further, the position tracking correction value is calculated as a difference between the temporal integrated values of the both quadruple frequency pulse signals corresponding to the encoder signals of the preceding tracking machines, and the value is proportional to the speed difference between the two machines. The positive and negative polarities express the slow speed relationship between the two machine speeds.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a control block diagram showing an embodiment of the present invention. In FIG. 1, 1a and 1b are machines that are driven by induction motors 2a and 2b, respectively, and are synchronously operated. In the case shown, 1a is a preceding machine and 1b is a follower machine. The subscripts a and b given to the respective constituent elements below refer to the machine elements 1a and 1 respectively.
It is shown that signal processing corresponding to b and b is performed. 3a and 3b are coupled to the respective corresponding machines to rotate, and a two-phase pulse signal of A phase and B phase having a phase difference of 90 degrees with each other according to the rotation angle, and for each one rotation thereof. The encoder outputs a one-pulse origin signal, that is, a Z-phase signal. Reference numerals 4a and 4b are insulating circuits, and 5a and 5b are shaping circuits for the A, B, and Z phase pulse signal waveforms that pass through the insulating circuits. 6a and 6b are frequency doubling direction discriminating circuits, which receive the pulse signals of the A phase and B phase, respectively, and synthesize and output a quadruple frequency pulse signal (A + B) of both signals to output one pulse of the signal. The angular resolution per hit is improved, and further, between the A-phase and B-phase pulse signals 9
The rotation direction of the corresponding encoder is determined based on the relative relationship between the lead and lag of the 0 degree phase difference. Reference numerals 7a and 7b are speed detection circuits, and in the case shown in the figure, the phase A pulse signal is input and the pulse period is compared with a clock signal to detect the rotational speeds fp and fc of the corresponding encoders, respectively. . The speed can be similarly detected when the B-phase pulse signal is input. Reference numeral 8 is a phase difference detection circuit between the origins of the encoders 3a and 3b, and uses the Z-phase pulse signals of the encoders 3a and 3b as clear and latch signals, respectively, within the difference period between the generation points of these signals. By counting the number of pulses of the quadruple frequency pulse signal from the frequency multiplication direction discriminating circuit 6a included, the phase difference α between the two encoder origins is detected as described below with reference to the rotation state of the encoder 3a. To do.

However, Nd: the number of counting pulses of the phase difference detection circuit 8 Ne: the number of pulses per one rotation of the encoder 3a The phase difference α corresponds to the positional deviation between the synchronization target reference points of the two machines at the time of starting the synchronization control of the two machines. It is an angle difference between both reference points of each encoder and indicates a required correction angle for synchronization. Reference numeral 9 denotes a deviation counter circuit, which counts a pulse number difference between the both quadruple frequency pulse signals (A + B) corresponding to the encoders 3a and 3b, and inputs the pulse number difference as an initial set value. It is to be subtracted from the number of pulses corresponding to the required correction angle from the phase difference detection circuit 8. Here, the pulse number difference between the both quadruple frequency pulse signals is proportional to the rotational speed difference between the both encoders and therefore both machines, and since the rotation angle per pulse is determined, the pulse number difference is The temporal integrated value of indicates the total displacement angle within the integrated period. The total displacement angle indicates a follow-up correction angle with respect to the required correction angle. Therefore, the output angle β of the deviation counter circuit 9, which is the difference between the both angles, indicates the remaining amount of the required correction angle at the time of counting the pulse difference. , Given below.

However, Nc: the number of output pulses of the deviation counter circuit 9 Ne: the number of pulses per rotation of the encoder 3a 10 and 11 are proportional-integral (PI) adjusters, and the angle β and the rotational speed difference fp- The output of the adder / subtractor calculator 15 for calculating fc is input. The rotation speed fp of the encoder 3a and both PI adjusters 10
The sum of the three of the outputs 11 and 11 is calculated by the acceleration / deceleration calculator 14, and the output fs is input to the inverter device 16 as a speed setting signal for the induction motor 2b of the follower to accelerate / decelerate the motor 2b. Control is done.
The output of the adjuster 10, which is the angle correction term of the speed setting signal, and the output of the adjuster 11, which is the speed correction term, reach zero with the progress of the synchronous control, and the rotational speed fc of the follower is the preceding speed. The rotation speed of the machine becomes equal to fp, and the synchronous control is completed.

〔The invention's effect〕

According to the present invention, the Z-phase pulse signal, which is the origin signal of the encoders respectively coupled to the two machines that are synchronously operated, is used as a reference, and the A-phase or B-phase generated by each of the encoders at a specified rotation angle. The position deviation between the origins of the two encoders, the respective speeds and their deviations are determined by the counting calculation of the pulse signals, and the speed control of the follower machine is performed so that the position deviation between the origins becomes zero. This makes it possible to shorten the time required for synchronization and simplify the synchronization operation by making reference point alignment unnecessary at the time of start-up, and to reliably and promptly perform correction control for synchronization deviation due to disturbance during synchronous operation.

[Brief description of drawings]

FIG. 1 is a control block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a control block diagram showing an embodiment of the prior art, and FIG. 3 is an output waveform and relative positional relationship diagram of the synchro electric machine in FIG. 1a ... Machine (preceding machine), 1b ... Machine (following machine), 2a,
2b ... Induction motor, 3a, 3b ... Encoder, 4a, 4
b ... Insulation circuit, 5a, 5b ... Shaping circuit, 6a, 6b ... Frequency multiplication direction determination circuit, 7a, 7b ... Speed detection circuit,
8 ... Phase difference detection circuit, 9 ... Deviation counter circuit, 10,
11 ... Proportional / integral (PI) adjuster, 14, 15 ... Addition / subtraction calculator, 16 ... Inverter device, 20a ... Synchronous electric machine (transmitter), 20b ... Synchronous electric machine (receiver), 21 ... Displacement detection circuit, 22 ... Motor drive circuit.

Claims (1)

[Claims] 1. A synchronous control device for the two machines, wherein one of the two machines driven by an induction motor is a preceding machine and the other is a follower for the preceding machine, and the two machines are synchronously controlled. Outputs a two-phase pulse signal of A phase and B phase having a phase difference of 90 degrees depending on the rotation angle and each origin and one pulse origin signal, that is, Z phase signal. Two sets of encoders, and two sets of frequency multiplication direction discriminating circuits that output a quadruple frequency pulse signal of the two-phase pulse signals of both encoders and discriminate the rotation direction of each corresponding encoder, Two sets of speed detection circuits for calculating the rotational speeds of the corresponding encoders from the A-phase or B-phase pulse signals of both encoders, and Z-phase pulse signals of both encoders. And a phase difference detection circuit for calculating the phase difference angle between the origins of the two encoders at the time of starting the synchronous control for the follower, by using the quadruple frequency pulse signal corresponding to the encoder of the preceding machine, and corresponding to both encoders. A deviation counter circuit for calculating a difference between integrated values of the quadruple frequency pulse signals including their signs and subtracting the integrated value difference from an output value of the phase difference detection circuit given as an initial set value; A first addition / subtraction calculator for calculating an output difference between both speed detection circuits, a sum of an output of the speed detection circuit corresponding to the preceding machine, an output of the deviation counter circuit, and an output of the first addition / subtraction calculator. A second adder / subtractor calculator for calculation and two sets of inverter devices for controlling the speeds of the two induction motors are provided, and the output of the second adder / subtractor calculator is used to induce induction of the follower. Synchronous control apparatus characterized by forming a set speed signal of the machine speed adjusting inverter device.