JP3221686B2 - Signal generator for motor speed control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase full-wave sensorless drive, which does not use a sensor but has one of three phases.
The present invention relates to a motor speed control signal generator that generates a stable FG signal (a signal having a frequency proportional to the number of rotations of a motor) which is synchronized with a phase and has no chattering.

[0002]

2. Description of the Related Art FIG. 4 is a schematic block diagram showing an example of a conventional normal motor speed control system. When a sensor (not shown) attached to a motor 1 detects a rotation speed, a rotation speed-frequency conversion unit 2 operates. Is converted into an FG signal (pulse wave) having a frequency proportional to the rotation speed, and is output. The frequency-voltage converter 3 converts the voltage into a voltage corresponding to the frequency of the FG signal and outputs the converted voltage. Comparator 4
2 is converted into a signal of a voltage corresponding to the difference between the voltage output from the frequency-voltage converter 3 and a preset speed reference voltage 41 and output. The ripple filter 5 outputs the signal of the voltage output from the comparator 42. The voltage-current converter 6 outputs a voltage signal obtained by removing a ripple from the signal, and the voltage-current converter 6 converts the voltage signal into a corresponding current and outputs the current.
Is adjusted to a current corresponding to the speed reference voltage 41 set in the comparator 42, and the rotation speed of the motor 1 is kept constant.

FIG. 5 shows a specific circuit example of the rotation speed / frequency converter shown in FIG.
The sine wave signal voltage input from the sensor of the motor 1 via the input terminal 20 is amplified by the amplifier 21 and compared with the reference voltage 23 by the hysteresis comparator 22. After being converted into a stable pulse waveform without chattering, this pulse waveform is output from the output terminal 24 to the frequency-voltage converter 3 (see FIG. 4) as an FG signal.

[0004]

In a driving device for a three-phase brushless motor, an induced voltage of a driven stator winding is shaped into a waveform to detect a rotor position of the motor 1 and a detection signal of a rotation frequency. Is generated, and based on the detection signal, the conduction angle at which the three stator windings of the first phase X, the second phase Y, and the third phase Z are conducted, and the drive current are controlled. The control of the rotor of the motor 1 is performed.

However, when the driving current of the motor 1 is switched, ringing occurs at the time of rising and falling of the driving current. And the output waveform of the hysteresis comparator 22, that is, the duty of the FG signal collapses.

In order to solve this problem, means has been used to add a capacitance between the terminals of the stator winding of the motor 1 to blunt the waveform of the induced voltage. If ringing is to be suppressed, a large capacity is required, which increases the volume of the driving device of the three-phase brushless motor and increases the cost.

If no capacitance is added between the terminals of the stator winding of the motor 1, the high value of the ringing will increase,
Since the transistor constituting the hysteresis comparator 22 connected to the stator winding is easily deteriorated, there is a problem that the capacitance between the terminals of the stator winding cannot be eliminated.

Further, the rotation speed / frequency conversion unit 2 as shown in FIG. 4 requires a sensor for obtaining information on the rotation speed of the motor 1 in addition to an increase in the number of elements, and thus the cost is increased. Problem.

In view of such circumstances, the present invention has a small number of elements and has a small capacitance that suppresses a high heading value of ringing to such an extent that a transistor constituting a hysteresis comparator is not deteriorated. It is an object of the present invention to provide a motor speed control signal generator capable of eliminating the influence and obtaining an FG signal stably synchronized with an output of one of three phases.

[0010]

According to the present invention, a voltage output of each phase obtained by shaping an induced voltage of a stator winding of a three-phase motor is taken out, and when the three-phase motor is in normal rotation, a first output is obtained. The coincidence output of the phase and the third phase and the coincidence output of the inversion output of the first phase and the third phase are respectively obtained as the coincidence output with the forward / reverse rotation control input voltage, and the former first and third phases are obtained. Output of the match
First means for controlling the rising and falling of the FG signal by inputting the coincidence output of the inverted output of the phase and the third phase to the set terminal and the reset terminal of the latch circuit, respectively, and the reverse rotation of the three-phase motor At the time, the coincidence output of the first phase and the second phase and the coincidence output of the inversion output of the first phase and the second phase are respectively obtained as the coincidence output of the inversion output of the forward / reverse rotation control input voltage. Output of the first and second phases, and the first
A second means for inputting the coincidence output of the inverted output of the phase and the second phase to the set terminal and the reset terminal of the latch circuit, respectively, to regulate the rising and falling of the FG signal. FG signal that is stably synchronized with the cycle of the input signal of one of the phases.

[0011]

According to the present invention, using a plurality of inverting circuits, a plurality of matching circuits, and one latch circuit, a matching output of a waveform-shaped voltage output of each phase and a forward / reverse rotation control input of a motor. By matching the voltage, there is no chattering of the shaped output waveform due to ringing at the time of switching operation of the stator winding of the motor, and a square wave stably synchronized with the cycle of the input signal of one of the three phases is obtained. Since the FG signal is obtained, the malfunction of the subsequent motor speed control circuit is eliminated,
The excitation current of the motor can be controlled stably.

Further, according to the present invention, a sensor for detecting the rotational speed of the motor is not required, and the value of the capacitance added between the terminals of the stator winding for suppressing the high head of ringing is small. As a result, the size and cost of the device can be easily reduced.

[0013]

FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIG.
Timing chart of each part at the time of forward rotation of the phase motor,
FIG. 3 is a timing chart of each part when the three-phase motor rotates in the reverse direction.

In FIG. 1, x, y, and z are three-phase X, Y, and Z square wave voltages obtained by converting an induced voltage (not shown) of a three-phase motor stator winding by a comparator [FIG.
(1), (2) and (3) or FIGS. 3 (1), (2) and (3)] are input three-phase input terminals.

V _FR is a forward / reverse rotation control input voltage which becomes H level during normal rotation of the three-phase motor and becomes L level during reverse rotation of the three-phase motor.

Each of Q _{a1 to} Q _a3 is an inverting circuit composed of an inverter circuit. The inverting circuits Q _{a1 to} Q _a3 shown in FIGS. 2 (4), (5) and (6) or 3 (4), (5) and (6) Square wave voltage of phase X, Y, Z

[Outside 1]

Q _a4 and Q _a5 are inverting circuits each constituted by an inverter circuit, and Q _a5 is a forward / reverse rotation control input voltage V
The inverted signal of _FR is output, and Q _a4 further inverts and outputs the inverted signal of the forward / reverse rotation control input voltage V _FR output by Q _a5 , in other words, outputs a signal that matches the forward / reverse rotation control input voltage V _FR. .

Each of Q _{b1 to} Q _b10 is a matching circuit composed of a NAND circuit. When the motor is rotating _forward , the matching circuits Q _b2 , Q _b2 ,
Q _b4 , Q _b6 , Q _b8 , and when the motor _rotates in reverse, the matching circuits Q _b1 ,
Q _b3, Q _b5, each match in Q _b7 is taken.

Q _c1 is a latch circuit composed of a flip-flop circuit with reset. A set terminal S receives a rising set input of an FG signal via Q _b9 , and a reset terminal R has a falling reset of the FG signal. The input is input via _Qb10 .

V _OUT is an output terminal of the FG signal.

The operation of the embodiment of the present invention configured as described above will be described with reference to the timing charts of FIGS.

First, at the time of normal rotation of the motor (see FIG. 2), a match between the signal X input to the input terminal x of the first phase and the signal Z input to the input terminal z of the third phase is determined by a matching circuit Q. Taking _b2 , when both the signal X and the signal Z are at the H level,
The output of match circuit _Qb2 is at L level.

When the motor is rotating forward, the forward / reverse rotation control input voltage V _FR goes high, so that the output of the inverting circuit Q _a5 goes low and the output of the inverting circuit Q _a4 goes high.

Therefore, the output of the coincidence circuit _Qb2 and the inversion circuit Qb2
_If the match with the output of _a4 is taken by the match circuit _Qb6 , the match circuit Q
_When the output of _b6 becomes H level,

[Outside 2]

That is, a set signal is input to the set terminal S of the latch circuit _Qc1 , and F is output from the output terminal V _OUT.
The G signal rises at the same time as the output of the coincidence circuit _Qb9 falls.

[Outside 3]

In addition, when the motor is rotating forward, since the forward / reverse rotation control input voltage V _FR is at H level, the output of the inverting circuit Q _a5 is at L level and the output of the inverting circuit Q _a4 is at H level.

Therefore, the output of the matching circuit _Qb4 and the inverting circuit Q
_When the match with the output of _a4 is taken by the match circuit _Qb8 , the match circuit Q
_When the output of _b8 becomes H level,

[Outside 4]

That is, a reset signal is input to the reset terminal R of the latch circuit _Qc1 , and the FG signal output from the output terminal V _OUT falls at the same time as the output of the coincidence circuit _Qb10 falls.

As described above, the rise and fall of the FG signal are regulated as shown in FIG. 2 (9), there is no chattering, and the FG signal is stably synchronized with the cycle of the signal X input to the input terminal x of the first phase. The output FG signal is output from the output terminal V _OUT .

Next, when the motor rotates in the reverse direction (see FIG. 3), a match between the signal X input to the input terminal x of the first phase and the signal Y input to the input terminal y of the second phase is determined by a matching circuit Q Taking _b1 , when both the signal X and the signal Y are at the H level,
The output of match circuit _Qb1 is at L level.

When the motor rotates in the reverse direction, the forward / reverse rotation control input voltage V _FR goes low, so that the output of the inverting circuit _Qa5 goes high.

Therefore, the output of the matching circuit Q _b1 and the inverting circuit Q
_When the match with the output of _a5 is taken by the match circuit _Qb5 , the match circuit Q
_When the output of _b5 becomes H level,

[Outside 5]

That is, a set signal is input to the set terminal S of the latch circuit _Qc1 , and F is output from the output terminal V _OUT.
The G signal rises at the same time as the output of the coincidence circuit _Qb9 falls.

[Outside 6]

When the motor rotates in the reverse direction, the output of the inverting circuit _Qa5 goes high because the forward / reverse rotation control input voltage V _FR is low.

Therefore, the output of the coincidence circuit _Qb3 and the inversion circuit Qb3
_When the match with the output of _a5 is obtained by the match circuit _Qb7 , the match circuit Q
_When the output of _b7 becomes H level,

[Outside 7]

That is, a reset signal is input to the reset terminal R of the latch circuit _Qc1 , and the FG signal output from the output terminal _VOUT falls at the same time as the output of the coincidence circuit _Qb10 falls.

As described above, the rise and fall of the FG signal are regulated as shown in FIG. 3 (9), and there is no chattering, and the FG signal is stably synchronized with the cycle of the signal X input to the first phase input terminal x. The output FG signal is output from the output terminal V _OUT .

That is, according to the present embodiment, chattering of the shaped output waveform due to ringing at the time of switching operation of the stator winding of the motor is eliminated, and the first-phase input terminal x
A FG signal of a square wave that is stably synchronized with the period of the signal X input to the FG is obtained.

[0039]

As described above, according to the present invention,
There is no chattering of the shaped output waveform due to ringing at the time of switching operation of the stator winding of the motor, and a square wave FG stably synchronized with the cycle of the input signal of one of the three phases.
Since the signal is obtained, the malfunction of the motor speed control circuit at the subsequent stage is eliminated, and the effect is obtained that the exciting current of the motor can be stably controlled.

Further, according to the present invention, a sensor for detecting the rotation speed of the motor is not required, and the value of the capacitance added between the terminals of the stator winding for suppressing the high head of ringing is small. As a result, the size and the price of the apparatus can be easily reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation at the time of forward rotation of the motor.

FIG. 3 is a timing chart for explaining the operation at the time of reverse rotation of the motor.

FIG. 4 is a schematic block diagram showing an example of a conventional motor speed control system.

FIG. 5 is a specific circuit diagram of a rotation speed-frequency conversion unit of a conventional motor speed control system.

[Explanation of symbols]

x, y, z phases X, Y, the output terminal Q _a1 to Q _a5 inverting circuit input terminal V _FR forward and reverse rotation control input voltage V _OUT FG signal Z (inverter circuit) Q _b1 to Q _b10 coincidence circuit Q _c1 Latch circuit (flip-flop circuit)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 6/00-6/24

Claims (1)

(57) [Claims] 1. A three-phase motor of the induced voltage of the stator winding eject the voltage output of each phase obtained by waveform shaping, during forward rotation of the 3-phase motor, first phase and the third phase the match output and matching the output of the inverted output of the first phase and the third phase of the, it
Respectively, forward and reverse rotation control for a match output of the input voltage, coincidence output of the first phase and the third phase of the former, the first phase and the third phase of the latter
Each set of the latch circuits match output of the inverted output of the
Respectively is inputted to the terminal and a reset terminal, first means for regulating the rise and fall of the FG signal, the reverse rotation of the three-phase motor, coincidence output and the second between the first and second phases the match output of the inverted output of the first phase and the second phase, it
Are each, for a match output and the inverting output of the forward and reverse rotation control input voltage, coincidence output of the first phase and the second phase of the former, a first latter
Each inverted output of the coincidence output to the set terminal and the reset terminal of each of the latch <br/> latch circuit is input between the phase and the second phase
So it includes a second means for regulating the rise and fall of the FG signal and in synchronization with the cycle of the voltage output of one phase of said three-phase F
A signal generator for motor speed control, wherein the signal generator generates a G signal.