JPH05122976A - Normal/reverse rotation discriminator for motor - Google Patents

Abstract

PURPOSE:To obtain a circuit for easily deciding a rotating direction of a motor at a high speed by checking a level of other phase pulse by a logic circuit when one of three phase pulses is varied, and deciding the rotating direction of the motor. CONSTITUTION:A U-phase pulse edge detector 1 detects rise and fall of a signal and outputs high levels U , U to output terminals Q1, Q2. V-phase and W- phase pulse edge detectors 2, 3 respectively output V , V and W , W . Here, when the U is output as a motor is forwardly rotated, a W-phase pulse is an 'H' level. An output of an AND gate 4 becomes 'H', and other AND gate also outputs 'H'. Accordingly, if the 'H' level is output from any of the AND gates, an 'H' level is output from an OR gate 10. On the other hand, when the motor is reversely rotated, 'L' is output. Accordingly, if the output is an 'H' level, the motor is forwardly rotted. Similarly, if AND gates 11-16 and an output of an OR gate 17 are 'H' level, the motor is reversely rotated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for determining the rotation direction of a motor, which is necessary when determining the phase of a current supplied to a synchronous AC servomotor.

[0002]

2. Description of the Related Art In a synchronous AC servomotor, the position of the rotor (rotor) (magnetic pole position) must be constantly grasped to determine the phase of the current to be supplied. As one method for that purpose, as shown in FIG.
Divide one cycle of electrical angle into six regions from one phase pulse,
By counting and interpolating the incremental type A and B signals in each of the divided areas, it is detected which position the magnetic pole is in the six zones, and based on this, the current supplied to the motor. There is a method to determine the phase of.

[0003]

However, in this method, as shown in FIG. 2, the count data of the A and B signals are set at the transition of each phase pulse (zone transition) and 0 at the time of normal rotation of the motor. Must be cleared to the maximum value during reverse rotation (cleared for normal rotation in Fig. 2). For that purpose, the direction of rotation of the motor must be detected. There was a time lag because the direction of rotation could not be detected at high speed. The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a circuit capable of easily and quickly determining the rotation direction of a motor from the output state of the phase pulse.

[0004]

According to the present invention, an optical encoder is used as a position detector of a rotor, and one cycle of an electrical angle is divided into 6 from three phase pulses output from the encoder, and each divided region is divided. In contrast to the incremental type A,
In the synchronous AC servomotor that detects the rotational position of the magnetic pole by counting and interpolating the B signal and is driven by a sinusoidal current synchronized with the rotational position, the motor required for the counting A circuit for determining the rotation direction, wherein when one of the three phase pulses changes, the level of the other phase pulse is checked by a logic circuit to determine the rotation direction of the motor. Is characterized by.

[0005]

The time charts of the three phase pulses at the time of forward rotation and at the time of reverse rotation of the motor are shown in FIGS. 3 and 4, respectively. Paying attention to these time charts, at the moment when one of the three phase pulses changes (at the rising edge and the falling edge), whether the level of one of the other two phase pulses is “H” or “L”. The forward / reverse rotation of the motor can be determined by detecting

For example, paying attention to the rising of the U phase in FIGS. 3 and 4, the V phase is at the "L" level and the W is at the normal rotation.
The phase is "H" level, but the V phase is "H" level and the W phase is "L" level during reverse rotation. Therefore, when the U phase rises, the forward / reverse rotation of the motor can be determined by detecting the level of either the V phase or the W phase.

[0007]

FIG. 5 is a control block diagram showing an embodiment of a motor forward / reverse rotation discrimination circuit according to the present invention. Reference numeral 1 denotes an edge detection circuit for the U-phase pulse, which detects rising and falling edges of a signal in the U-phase pulse and outputs high levels (U ↑ and U ↓, respectively) to output terminals Q ₁ and Q ₂ , respectively.
Is output). Reference numerals 2 and 3 denote edge detection circuits for V-phase and W-phase pulses, which detect rising and falling edges of the signal and output terminals Q ₁ , respectively.
V ↑, V ↓ and W ↑, W ↓ are output to Q ₂ .

The AND gate 4 receives U ↑ and W phase pulses as inputs, and therefore the output of the gate 4 can be represented by U ↑ · W (“·” is a logical product). Similarly, AND gate 5
Outputs 9 to 9 are W ↓ ・ U, V ↑ ・ U, U ↓, respectively.
・ V, W ↑ ・ V, V ↓ ・ W The output of the OR gate 10 which receives these outputs is U ↑ · W + W ↓ · U +
V ↑ ・ U + U ↓ ・ V + W ↑ ・ V + V ↓ ・ W
(“+” Indicates a logical sum).

Here, at the time of normal rotation of the motor, as can be seen from FIG. 3, the W-phase pulse is "H" when U ↑ is output.
The level is the output of the AND gate 4 U ↑ · W = “H”
And the other AND gates 5 to 9 are also "H".
Is output. Therefore, if the "H" level is output from any of the AND gates 4 to 9, the OR gate 10
The "H" level is output. On the other hand, when the motor is rotated in the reverse direction, as can be seen in FIG. 4, the AND gates 4 to 9 all output the "L" level, so that the output of the OR gate 10 becomes "L". Therefore, if the output of the OR gate 10 is at "H" level, it means that the motor is rotating normally, and therefore this output signal can be used as a clear signal to the above-mentioned counter.

Similarly, the outputs of the AND gates 11 to 16 are U ↓ · W, V ↑ · W, W ↓ · V and U ↑ ·, respectively.
The output of the OR gate 17 is represented by V, V ↓ · U, W ↑ · U, and the output of the OR gate 17 is U ↓ · W + V ↑ · W + W ↓ · V + U ↑ · V + V ↓ · U +.
W ↑ ・ U. Here, when the motor rotates in the reverse direction, as shown in FIG. 4, the AND gates 11 to 16 output "H", respectively.
The ND gates 11 to 16 output "L" level.
Therefore, if the output of the OR gate 17 is at the "H" level, it means that the motor is rotating in reverse, and therefore this output signal can be used as the load signal to the counter described above.

[0011]

As described above, according to the present invention, the rotation direction of the motor can be determined by checking the levels of the three phase pulses which are the magnetic pole detection signals with the logic circuit. You can eliminate the time lag.

[Brief description of drawings]

FIG. 1 is a diagram showing zones divided for one electrical angle period.

FIG. 2 is a conceptual diagram for detecting a magnetic pole position.

[Fig. 3] Time chart of phase pulse in forward rotation

[Fig. 4] Time chart of phase pulse during reverse rotation

FIG. 5 is a control block diagram showing an embodiment of a motor forward / reverse rotation determination circuit of the present invention.

[Explanation of symbols]

 1 Edge Detection Circuit 2 Edge Detection Circuit 3 Edge Detection Circuit 4 AND Gate 5 AND Gate 6 AND Gate 10 OR Gate 11 AND Gate 12 AND Gate 12 AND Gate 13 AND Gate 17 OR Gate

Claims (1)

[Claims] 1. An optical encoder is used as a position detector of a rotor, one cycle of an electrical angle is divided into 6 from three phase pulses output from the encoder, and an incremental type A, A synchronous AC servomotor that detects a rotational position of a magnetic pole by counting and interpolating a B signal and is driven by a sine wave current synchronized with the rotational position, in a motor required for the counting. A circuit for determining the rotation direction, wherein when one of the three phase pulses changes, the level of the other phase pulse is checked by a logic circuit to determine the rotation direction of the motor. A forward / reverse rotation discrimination circuit for a motor characterized by: