JPH09121581A - Control method of synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the control method of a synchronous motor with which the synchronous motor can be controlled by an economical controller. SOLUTION: Output signals are taken out from a commutation sensor 2 and a speed generator 3. In a low revolution state wherein the revolution of a synchronous motor 1 is not higher than a predetermined value or the output level of the speed generator 3 is not higher than a predetermined value, energization of the synchronous motor 1 is controlled in accordance with the output signal of the commutation sensor 2. In a high revolution state wherein the revolution of the synchronous motor 1 exceeds the predetermined value or the output level of the speed generator 3 exceeds the predetermined value, energization of the synchronous motor 1 is controlled in accordance with the output signal of the speed generator 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor control method for driving a synchronous motor such as a main motor for an electric vehicle or an industrial control motor.

[0002]

2. Description of the Related Art FIG. 7 shows a block diagram of a conventional controller for a synchronous motor. As shown in FIG. 7, the control device for the synchronous motor includes a synchronous motor 51 used as a main motor for an electric vehicle, an industrial control motor, etc., and an encoder 52 for detecting a rotational position of a rotor. There is.
This encoder 52 creates an A-phase signal and a B-phase signal whose phase is deviated by 90 degrees with respect to the A-phase signal over the entire circumference on the peripheral portion of a glass disk provided with a light-shielding film, which rotates in conjunction with the rotor. A large number of light-transmitting parts for forming a Z-phase signal (zero-phase signal) corresponding to the reference position of the rotor are formed on the peripheral edge of the disk. It is formed such that a light emitting element such as a light emitting diode and a light receiving element such as a photodiode are fixedly arranged so as to face each other at both light transmitting portion forming portions of the disk.

The A output from the encoder 52
The phase signal ENA, the B-phase signal ENB and the Z-phase signal ENZ are sent to an up / down counter 53 which is an address generating means of a waveform memory 54 described later. The synchronous motor 51
When the rotor of is rotating in one direction, for example, the A-phase signal ENA is advanced by 90 degrees compared with the B-phase signal ENB,
When the rotor is rotating in the opposite direction, for example, the A-phase signal ENA is delayed by 90 degrees with respect to the B-phase signal ENB.

The up / down counter 53 receives the A phase signal ENA, the B phase signal ENB and the Z phase signal ENZ sent from the encoder 52, resets the count value in response to the pulse input of the Z phase signal ENZ, and A
When the phase signal ENA leads the B-phase signal ENB by 90 degrees, it counts up at the rising and falling edges of the pulses of the A-phase signal ENA and the B-phase signal ENB, and the A-phase signal ENA lags the B-phase signal ENB by 90 degrees. While the A-phase signal ENA and the B-phase signal ENB rise and fall, the pulse counts down, and the count value as an output is supplied as an address to the waveform memory 54 as described above. It increases or decreases according to the rotation angle of the rotor of the electric motor 51 from the reference position.

The waveform memory 54 is a ROM in which waveform data for two phases of three-phase sine waves for one cycle is written.
And the count value of the up / down counter 53 is used as an address input for two phases (for example, U phase and V phase) corresponding to the rotation angle of the rotor of the synchronous motor 51 from the reference position.
Phase) waveform data is read. In addition, this waveform memory 5
Waveform data for three phases may be written in No. 4.

The digital / analog converters 55 and 56 are
Two phases (eg, for example, sequentially read from the waveform memory 54)
Waveform data of (U-phase and V-phase) are converted into analog voltage values to generate energization target current signals i _U ^* , _iv ^* of U-phase and V-phase having sine waveforms. The signal synthesizer 57
The U-phase and V-phase energization target current signals i _U ^* and _iv ^* are added and synthesized to create a sinusoidal W-phase energization target current signal i _W ^* . When the waveform data for three phases is written in the waveform memory 54, the W-phase waveform data is read from the waveform memory 54 and is input to the additional digital-analog converter, so that the W-phase energization target is obtained. The current signal i _W ^* can be generated, and the signal synthesizer 57 is unnecessary.

The driver 58 is a digital / analog converter.
U supplied from the devices 55 and 56 and the signal synthesizer 57
Target current signal i for phase V, phase V and phase W_U ^*,
i_v ^*, I_W ^*To the synchronous motor 51 based on
And the drive current i of each phase of W phase_U, I _v, I_WSupply
You. Usually drive current i_U, I_v, I_WAs the energization target
Current signal i_U ^*, I_v ^*, I_W ^*And in-phase current respectively
Only the components are supplied to the synchronous motor 51,
Stream signal i_U ^*, I_v ^*, I_W ^*90 degrees away from the voltage
Flow component is also supplied, in-phase component and 90 degree phase difference component
The field weakening control can be performed by adjusting the amplitude ratio of
And the rotational speed-torque characteristic of the synchronous motor 51 is normally set.
It can be changed when driving.

A resolver may be used in place of the encoder for detecting the rotation of the synchronous motor 51.

[0009]

As described above, as in the case of performing the field weakening control of the synchronous motor 51, for example,
When drive control is performed with a sine wave, detailed phase information corresponding to the rotational position of the rotor of the synchronous motor 51 is required to read the waveform data from the waveform memory 54. Therefore, the encoder 52 or the resolver is required. ing. However, the encoder 52 and the resolver are expensive, and the control device for the synchronous motor becomes expensive, so that the cost of the electric vehicle or the industrial equipment in which the synchronous motor 51 is incorporated is high.

Therefore, an object of the present invention is to provide a control method for a synchronous motor, which can make the control device for the synchronous motor inexpensive.

[0011]

A method of controlling a synchronous motor according to claim 1, wherein an output signal is taken out from a commutation sensor and a speed generator attached to the synchronous motor, and the rotational speed of the synchronous motor is a predetermined low speed or less. Energization of the synchronous motor is controlled based on the output signal of the commutation sensor during rotation, and energization of the synchronous motor is controlled based on the output signal of the speed generator during high-speed rotation when the rotational speed of the synchronous motor exceeds a predetermined rotational speed. When the number of revolutions of the synchronous motor is lower than a predetermined number of revolutions, the output signal level of the speed generator is not sufficient.Therefore, the synchronous motor can be operated based on the output signal of the commutation sensor to obtain the required level regardless of the rotational speed. Energize control. On the other hand, when the number of revolutions of the synchronous motor exceeds the predetermined number of revolutions at high speed,
Since the level of the output signal of the speed generator is increased sufficiently,
Energization of the synchronous motor is controlled based on the output signal of the speed generator. At this time, since detailed rotation phase information can be obtained from the output signal of the speed generator, high-speed response and high-precision phase control of the drive current of the synchronous motor becomes possible.

According to a second aspect of the present invention, there is provided a synchronous motor control method.
The output signal is taken out from the rectification sensor attached to the synchronous motor and the speed generator, and when the output signal of the speed generator falls below a predetermined level, the synchronous motor is energized and controlled based on the output signal of the rectification sensor, When the output signal of the generator becomes a high level exceeding a predetermined level, energization control of the synchronous motor is performed based on the output signal of the speed generator. When the number of revolutions of the synchronous motor is lower than the predetermined number of revolutions,
Since the level of the output signal of the speed generator is not sufficient, the energization control of the synchronous motor is performed based on the output signal of the rectification sensor that provides the required level regardless of the rotation speed. on the other hand,
When the rotational speed of the synchronous motor is higher than a predetermined rotational speed, the output signal level of the speed generator is sufficiently increased, so that the synchronous motor is energized based on the output signal of the speed generator. At this time, since detailed rotation phase information can be obtained from the output signal of the speed generator, high-speed response and high-precision phase control of the drive current of the synchronous motor becomes possible.

A method of controlling a synchronous motor according to claim 3 is
In the control method for the synchronous motor according to claim 1 or 2, the zero-phase signal in the energization control of the synchronous motor by the output signal of the speed generator is created with reference to the output signal of the rectification sensor. The output signal of the speed generator only generates the signal of the frequency in response to the rotation of the synchronous motor, and the energization control of the synchronous motor by the output signal of the speed generator is
A zero-phase signal corresponding to the reference position of the rotor is required,
This zero-phase signal can be obtained from the output signal of the rectification sensor, and a dedicated zero-phase signal detecting means is unnecessary.

According to a fourth aspect of the present invention, there is provided a synchronous motor control method.
In the method for controlling a synchronous motor according to claim 3, the zero-phase signal is generated at a timing corresponding to a phase of 30 degrees of the reference phase. Assuming that the zero-phase signal is generated at the timing corresponding to the phase of 30 degrees of the reference phase, the process of detecting the rising or falling without delaying the waveform of the reference phase of the output signal of the rectification sensor. A zero-phase signal can be created simply by performing.

A method for controlling a synchronous motor according to claim 5 is
The control method for a synchronous motor according to claim 1 or 2, wherein the control signal generated based on the output signal of the rectification sensor is a rectangular wave signal, and the control signal generated based on the output signal of the speed generator is a sine wave. It is a wave signal. Therefore, the synchronous generator is driven with a rectangular wave at low speed rotation and is driven with a sine wave at high speed rotation.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a control method for a synchronous motor according to the present invention will be described below with reference to FIG.
FIG. 1 shows a block diagram of a synchronous motor control device for carrying out a synchronous motor control method according to an embodiment of the present invention. As shown in FIG. 1, the control device for this synchronous motor is
A commutation sensor 2 for detecting the rotational position of a rotor of a synchronous motor 1 used as a main motor for an electric vehicle, an industrial control motor, etc. and a speed generator (FG; Frequency Generator) 3 are attached. doing. The commutation sensor 2 has, for example, a structure in which a Hall element detects a change in magnetic flux accompanying the rotation of the main magnet of the synchronous motor 1, or a structure in which the rotational position of the rotor of the synchronous motor 1 is detected by an electromagnetic means described later. Things are adopted. Further, as the speed generator 3, a multi-pole generator, for example, a structure using a step motor as a generator, or an ordinary pattern coil type FG is adopted.

The rectification sensor 2 outputs three-phase output signals CS1, CS2, CS3 corresponding to the rotational position of the rotor.
Three-phase output signals CS1, CS2, C of this rectification sensor 2
S3 is used after being shaped into a rectangular wave signal as shown in FIGS. 3 (a), 3 (b) and 3 (c). Three-phase output signal C
Some of S1, CS2, and CS3 are output as rectangular wave signals, and in this case, waveform shaping can be omitted. In the figure, the output signal CS1 corresponding to the reference phase (U phase) has a "1" level from 0 to 180 degrees and a "0" level from 180 to 360 degrees. Also, the output signal C
S2 is "0" level from 0 to 120 degrees,
From 120 degrees to 300 degrees, the level is "1", 30
The level is "0" from 0 to 360 degrees. The output signal CS3 is at the "1" level from 0 to 60 degrees and at the "0" level from 60 to 240 degrees, and is 240.
From 1 degree to 360 degrees, the level is "1". That is, 3
The phase output signals CS1, CS2, CS3 have a phase difference of 120 degrees with each other.

On the other hand, the speed generator 3 generates electric power by rotating in conjunction with the synchronous motor 1 and has a multi-pole structure (the number of poles is about 50 to 300). The two-phase output signals FGA and FGB are sinusoidal signals whose frequency is proportional to the rotation speed of the rotor and whose amplitude increases as the rotation speed increases, as shown in FIG.
As shown in (e), the waveform is shaped into a rectangular wave signal for use, and when the rotor is rotating in one direction, the A-phase signal F
GA is advanced by 90 degrees compared with the B-phase signal FGB, and when the rotor is rotating in the opposite direction, the A-phase signal FGA is B
The phase is delayed by 90 degrees compared to the phase signal FGB, and the A phase signal FG
The rotation direction of the synchronous motor 1 can be determined based on the phase relationship between the A and B phase signals FGB. Note that some of the two-phase output signals FGA and FGB output rectangular wave signals, and in this case, waveform shaping can be omitted.

The voltage determination circuit 4 compares the level of the A-phase output signal FGA output from the speed generator 3 before shaping with a predetermined threshold value. As for this threshold value, a sufficient S / N ratio is obtained and the output signals FGA, FG of the speed generator 3 are
B is set to a level at which it can be used to control the synchronous motor 1. Then, the output signal FG of the speed generator 3
When the output level of A is equal to or lower than the threshold value, that is, when the rotation speed of the speed generator 3 is equal to or lower than the predetermined rotation speed, the gate 5 is turned on and the gates 6 and 7 are turned off. In addition, speed generator 3
When the output level of the output signal FGA of 1 exceeds a threshold value, that is, when the rotation speed of the speed generator 3 exceeds a predetermined rotation speed, the gate 5 is cut off and the gates 6 and 7 are made conductive. That is, when the output level of the output signal FGA of the speed generator 3 is equal to or lower than the threshold value, that is, when the rotation speed of the speed generator 3 is equal to or lower than the predetermined rotation speed, the three-phase output signal CS1 output from the rectification sensor 2 is output. , CS2, CS3 to control the synchronous motor 1 to output the output signal FGA of the speed generator 3.
When the output level of the speed generator 3 exceeds a threshold value, that is, when the rotation speed of the speed generator 3 exceeds a predetermined rotation speed, the synchronous motor is generated based on the two-phase output signals FGA and FGB output from the speed generator 3. 1 will be controlled. Hereinafter, this point will be described in detail.

The waveform memory 8 is composed of, for example, a ROM, and the waveform of two phases (for example, U phase and V phase) of the three-phase rectangular wave for one cycle for controlling the drive of the synchronous motor 1. Similarly to the data, the waveform data of two phases (for example, U phase and V phase) of the sine wave of three phases for one cycle are stored at different addresses. Of course, waveform data for three phases may be stored.

The rectangular wave address generation circuit 9 outputs the three-phase output signals CS1, CS2, CS output from the rectification sensor 2.
3 is input, and an address for reading the rectangular wave waveform data is output to the waveform memory 8. This address is a three-phase output signal CS1, CS2 of the rectification sensor 2.
It takes different values corresponding to the combination of "1" and "0" of the levels of each phase in one cycle period of CS3, and in FIG. 3, generates different addresses for each interval of 60 degrees. Become.

The address output from the rectangular wave address generating circuit 9 is an address when the output level of the output signal FGA of the speed generator 3 is below a threshold value, that is, when the rotation speed of the speed generator 3 is below a predetermined rotation speed. , The gate 5 becomes conductive, so that it is input to the waveform memory 8 through the OR gate 10. As a result, from the waveform memory 8 to the synchronous motor 1
The waveform data of the rectangular wave is output in the phase corresponding to the rotation of the.

The digital-analog converters 11 and 12 are
Two phases (for example, U
Phase and V phase) waveform data are converted into analog voltage values to generate rectangular waveform U-phase and V-phase energization target current signals i _U ^* , _iv ^* . The signal synthesizer 13 is U
Phase- and V-phase energization target current signals i _U ^* and _iv ^* are added and combined to create a rectangular waveform W-phase energization target current signal i _W ^* . When the waveform data for the three phases is written in the waveform memory 8, the W-phase waveform data is read from the waveform memory 8 and is input to the additional digital-analog converter to obtain the W-phase energization target. Current signal i _W ^*
Can be created, and the signal synthesizer 13 is unnecessary.
3 (d), 3 (e) and 3 (f), FIGS.
(C) shows the energization target current signals i _U ^* , _iv ^* , and i _W ^* for the U-phase, V-phase, and W-phase, which are created based on the three-phase rectangular wave signals CS1, CS2, CS3.

The driver 14 is a digital / analog converter.
U supplied from the devices 11 and 12 and the signal synthesizer 13.
Target current signal i for phase V, phase V and phase W_U ^*,
i_v ^*, I_W ^*To the synchronous motor 1 based on
And drive current i of each phase of W phase_U, I_v, I_WSupply
You. At this time, the synchronous motor 1 has a structure shown in FIGS.
As you can see from the waveform in (f),
De-energization is stopped during the 30 degree period and constant power is maintained during the central 120 degree period.
A rectangular wave drive of 120-degree energization for energizing the flow is performed.

On the other hand, when the output level of the output signal FGA of the speed generator 3 exceeds the threshold value, that is, the speed generator 3
When the number of rotations exceeds the specified number of rotations, the gates 6, 7
Is conducted, the two-phase output signals FGA and FGB output from the speed generator 3 as shown in FIGS.
Is input to the up / down counter 15. The zero-phase pulse generation circuit 16 has a reference phase A from the rectification sensor 2.
The output signal CS1 of the phase is always input, and the output signal CS1 of FIG.
As shown in, the Z-phase signal CSZ that produces one pulse is output at the rising timing of the output signal CS1 of the A-phase, and this Z-phase signal CSZ is also input to the up / down counter 15.

As a result, the up / down counter 15 is
The count value is reset in response to the pulse input of the Z-phase signal CSZ, and the A-phase signal FGA changes to the B-phase signal FGB.
When it is advanced by 90 degrees, it counts up at the rising and falling edges of the pulses of the A-phase signal FGA and the B-phase signal FGB, and when the A-phase signal FGA is behind the B-phase signal FGB by 90 degrees, the A-phase signal FGA. And the count value as the output is counted down at the rising and falling edges of the pulse of the B-phase signal FGB.
Although it is supplied as an address to the waveform memory 8 through 0, it increases or decreases according to the rotation angle of the rotor of the synchronous motor 1 from the reference position. As a result, waveform data of two phases (for example, U phase and V phase) corresponding to the rotation angle from the reference position of the rotor of the synchronous motor 1 is obtained from the waveform memory 8 using the count value of the up / down counter 15 as an address input. Read out.

The digital / analog converters 11 and 12 are
Two phases (for example, U
Phase and V phase) waveform data are converted into analog voltage values to generate sine waveform U-phase and V-phase energization target current signals i _U ^* , _iv ^* . The signal synthesizer 13 is U
Phase- and V-phase energization target current signals i _U ^* and _iv ^* are added and combined to create a sinusoidal W-phase energization target current signal i _W ^* . When the waveform data for the three phases is written in the waveform memory 8, the W-phase waveform data is read from the waveform memory 8 and is input to the additional digital-analog converter to obtain the W-phase energization target. Current signal i _W ^*
Can be created, and the signal synthesizer 13 is unnecessary.
2F, 2G, and 2H, sinusoidal U-phase, V-phase, and W-phase energization target current signals i _U output from the digital / analog converters 11 and 12 and the signal combiner 13.
^* Indicates a i _v ^*, i _v ^* of the waveform. In addition, FIG.
In (b) and (c), the waveforms of the rectangular-wave-shaped U-phase, V-phase, and W-phase energization target current signals i _U ^* , _iv ^* , and _iv ^* are also shown, and the low-speed rotation of the synchronous motor 1 is shown. energizing the target current signal at the time of time and high speed ^{_{i U *, i v *,}} i v * of the phase relation is set to be clarified.

The driver 14 is a digital / analog converter.
U supplied from the devices 11 and 12 and the signal synthesizer 13.
Target current signal i for phase V, phase V and phase W_U ^*,
i_v ^*, I_W ^*To the synchronous motor 1 based on
And drive current i of each phase of W phase_U, I_v, I_WSupply
You. Usually drive current i_U, I_v, I_WAs the energization target
Current signal i_U ^*, I_v ^*, I_W ^*And in-phase current respectively
Only the components are supplied to the synchronous motor 1. The energization target
Current signal i_U ^*, I_v ^*, I_W ^*Shifted by 90 degrees
The current component is also supplied, and the in-phase component and 90-degree phase difference are generated.
For phase control of sine wave by adjusting the amplitude ratio with minute
Field weakening control can be performed by the synchronous motor 1.
The number-of-turns-torque characteristic can be changed from that at the normal time.

FIG. 4 is a schematic diagram showing an example of the structure of a speed generator used in the control device for the synchronous motor of FIG. The speed generator includes a magnet rotor 31 having a large number of comb tooth-shaped concavities and convexities on the outer periphery that rotates in conjunction with the rotary shaft of the synchronous motor, and a ring-shaped yoke fixedly arranged so as to surround the magnet rotor 31. 32, and the magnet rotor 31 is provided on the yoke 32 so as to project inwardly so as to face the magnet rotor 31 and at the tip end thereof.
4 magnetic poles 33 having comb tooth-shaped irregularities with the same pitch as
36 and four windings 37 to 40 wound around four magnetic poles.

Of the four magnetic poles 33 to 36, the two magnetic poles 33 and 35 are arranged in the same phase relationship with the irregularities of the magnet rotor 31, and the remaining two magnetic poles 34 and 36 are also magnet rotors. The magnetic poles 3 are arranged in the same phase relationship with respect to the unevenness of 31
The magnetic pole 3 and the magnetic pole 34, and the magnetic pole 35 and the magnetic pole 36 are arranged in a phase relationship that is deviated by 90 degrees with respect to the irregularities of the magnet rotor 31.

Windings 37, 3 wound around the magnetic poles 33, 35
Reference numeral 9 is for extracting the A-phase signal, which are connected in series, and an AC voltage whose frequency is proportional to the rotation speed of the rotor of the synchronous motor and whose amplitude increases with the increase of the rotation speed appears at both ends thereof. . The windings 38 and 40 wound around the magnetic poles 34 and 36 are for extracting B-phase signals.
They are connected in series, and an AC voltage whose frequency is proportional to the rotation speed of the rotor of the synchronous motor and whose amplitude increases as the rotation speed increases appears at both ends of the winding 37, The phase is 90 degrees out of phase with the voltage appearing at 39.

Since the above-mentioned frequency generator is premised on use at high speed rotation in which the rotation speed has increased to some extent, a sufficiently high signal level can be obtained even with a structure having a large number of pulses, that is, high resolution. , The S / N ratio is good, and when the synchronous motor is controlled, the detection of a pulse is not missed and the synchronous motor can be controlled with high accuracy. Moreover, in terms of cost, it is sufficiently lower than the encoder, and because it is electromagnetic and does not use a semiconductor element, it has good heat resistance.

FIG. 5 is a schematic view showing an example of the structure of a rectifying sensor used in the control device for the synchronous motor of FIG. This commutation sensor has a rotor 20 made of a magnetic material that rotates in conjunction with the rotary shaft of a synchronous motor, a ring-shaped yoke 21 fixedly arranged so as to surround the rotor 20, and protrudes inward from the yoke 21. The three exciting magnetic poles 22A, 22B and 22C facing the rotor 20, and the three detecting magnetic poles 23A protruding inward from the yoke 21 and facing the rotor 20.
23B, 23C and magnetic poles 22A, 22B, 22C for excitation
Excitation windings 24A, 24B, 24C wound around the coil and the detection winding 2 wound around the detection magnetic poles 22A, 22B, 22C.
It consists of 5A, 25B and 25C.

Three exciting magnetic poles 22A, 22B, 22C
Are arranged in a predetermined phase relationship with the armature of the synchronous motor, and are arranged with a phase difference of 120 degrees from each other. Similarly, three detection magnetic poles 23A, 23B, 23C
Are arranged in a predetermined phase relationship with the armature of the synchronous motor, and are arranged with a phase difference of 120 degrees from each other. The three excitation magnetic poles 22A, 22B and 22C and the three detection magnetic poles 23A, 23B and 23C are arranged with a phase difference of 60 degrees and a phase difference of 60 degrees. That is, six magnetic poles are arranged 60 degrees apart, and every other three magnetic poles are excitation magnetic poles 22A, 22B and 22C, and the remaining three magnetic poles are detection magnetic poles 23A, 23B and 23C.

Excitation windings 24A, 24B, 24
C is connected in parallel, and these excitation windings 24A, 24
When a high-frequency current is applied to B and 24C from the high-frequency power source 26 to excite the exciting magnetic poles 22A, 22B and 22C with high frequency,
The high frequency voltages W1, W2, W3 determined by the positional relationship between the rotor 20 and the detection magnetic poles 23A, 23B, 23C are induced from the detection windings 25A, 25B, 25C, and the rotor 2
When 0 rotates, as shown in FIGS. 6A, 6B, and 6C, the envelopes of the induced high-frequency voltages W1, W2, and W3 change in a sinusoidal shape, and the detection windings 25A and 25B, 25C
The phases of the envelopes of the high-frequency voltages W1, W2, and W3 induced from are shifted by exactly 120. By detecting the waveforms of FIGS. 6A, 6B, and 6C and shaping the waveforms with a predetermined threshold value, the waveforms of FIGS.
Waveforms such as the output signals CS1, CS2, CS3 of the rectification sensor 3 shown in (b) and (c) are obtained.

Although the output voltage of the speed generator disappears when the rotation stops, if the structure shown in FIG. 5 is adopted, the output level is changed only by the position of the rotor of the synchronous motor, regardless of the rotational speed of the synchronous motor. The output varies depending on the position of the rotor even when the rotor is stationary, and the sensor can be used as a commutation sensor.

As described above, the rectification sensor having the structure shown in FIG.
Although the resolution is low, the output can be taken out even in a stationary state, the structure is electromagnetic, the cost is low, the heat resistance is sufficient, and it can be used even at high temperature. As described above, in this synchronous motor control device, the three-phase output signals CS1, CS from the rectification sensor 2 attached to the synchronous motor 1 are output.
2, CS3 is taken out, two-phase output signals FGA, FGB are taken out from the speed generator 3, and when the rotation speed of the synchronous motor 1 is a low speed rotation below a predetermined rotation speed, that is, when the output signal FGA is below a predetermined level. Three-phase output signal CS
1, CS2, CS3 to control the energization of the synchronous motor 1, and when the rotational speed of the synchronous motor 1 exceeds a predetermined rotation speed, that is, when the output signal FGA of the speed generator 3 exceeds a predetermined level, two-phase The energization control of the synchronous motor 1 is performed based on the output signals FGA and FGB.

That is, the output signal FG of the speed generator 3 is generated when the rotational speed of the synchronous motor 1 is lower than the predetermined rotational speed.
Since the levels of A and FGB are not sufficient, they are not used for the control of the synchronous motor 1. At this time, the output signal CS1,
Energization of the synchronous motor 1 is controlled based on CS2 and CS3. Output signals CS1, CS2, CS of this rectification sensor 2
Since detailed rotation phase information cannot be obtained from 3, the high-speed response and high-accuracy phase control of the drive current of the synchronous motor 1 is not performed during low-speed rotation. On the other hand, when the rotational speed of the synchronous motor 1 exceeds a predetermined rotational speed, the levels of the output signals FGA and FGB of the speed generator 3 are sufficiently increased, so that the output signals FGA and FGB of the speed generator 3 are set to the synchronous motor. 1 can be used to control the output signal FGA of the speed generator 3,
The energization of the synchronous motor 1 is controlled based on the FGB. At this time, since detailed rotation phase information is obtained from the output signals FGA and FGB of the speed generator 3, high-speed response and high-accuracy phase control of the drive current of the synchronous motor 1 is possible.

As described above, the output signal C of the rectification sensor 2
Output signal FG of S1, CS2, CS3 and speed generator 3
Since the synchronous generator 1 is controlled using A and FGB, and the rectification sensor 2 and the speed generator 3 can be manufactured at lower cost than the encoder of the conventional example, the control device for the synchronous motor can be manufactured at low cost. You can Further, since the rectification sensor and the speed generator are used in a form of compensating each other's drawbacks, it is possible to obtain a resolution comparable to that of the encoder. Further, both the rectification sensor 2 and the speed generator 3 can have a structure similar to that of a heat-resistant motor and do not have a built-in semiconductor element, and have excellent heat resistance as a control device for a synchronous motor. Therefore, it is possible to obtain high reliability, it can be used even in a high temperature environment, and it can be incorporated in a synchronous motor.

Further, the output signals FGA, F of the speed generator 3
The Z-phase signal in the energization control of the synchronous motor 1 by GB is created based on the output signal CS1 of the rectification sensor 2. The output signals FGA, FGB of the speed generator 3 only generate a signal of a frequency in response to the rotation of the synchronous motor 1, and the energization control of the synchronous motor 1 by the output signals FGA, FGB of the speed generator 3 is used for rotation. A Z-phase signal corresponding to the reference position of the child is required, but this Z-phase signal can be obtained from the output signal CS1 of the rectification sensor, a dedicated zero-phase signal detecting means is unnecessary, and the cost is low. .

Further, the Z-phase signal is generated at the timing corresponding to the phase of 30 degrees of the reference phase, but the Z-phase signal is generated at the timing corresponding to the phase of 30 degrees of the reference phase. Then, the output signal CS of the rectification sensor 2
The Z-phase signal can be created only by performing the process of detecting the rising edge or the falling edge without performing the delay process on the waveform of 1. Therefore, the circuit for generating the Z-phase signal can be manufactured at low cost.

In the above embodiment, the speed generator 3 is used.
The two-phase output signals FGA and FGB are directly added to the up / down counter 15 to output the two-phase output signals FGA and FG.
Counts up and down at the rising and falling edges of B, and outputs two-phase output signals FGA, FG
The waveform data is read from the waveform memory 8 at the rising and falling edges of B, and the waveform data could only be read at a cycle determined by the number of poles of the speed generator 3. However, using a timer configured by software A pulse that interpolates the rising and falling edges of the two-phase output signals FGA and FGB is created, and the pulse created by this interpolation is also added to the up / down counter, and the waveform data is stored from the waveform memory 8 at a short cycle including the interpolation pulse. By reading out, it is possible to perform fine control. In this case, the waveform data to be written in the waveform memory 8 also needs to be stored finely corresponding to the interpolation.

In the above embodiment, the speed generator 3 is used.
Of the output signal FGA is controlled by the voltage determination circuit 4 to control the gates 5 to 7. However, instead of the voltage determination circuit 4, for example, a means for measuring the frequency of the output signal of the rectification sensor 2 is provided. It may be determined whether the frequency of the output signal 2 is higher or lower than a predetermined frequency, and the gates 5 to 7 may be controlled based on the determination result. That is, the number of revolutions of the synchronous motor 1 is detected, whether the number of revolutions is high or low is determined, and based on the result of the determination, the synchronous motor is generated based on the output signal of the commutation sensor when the number of revolutions of the synchronous motor is a predetermined number of revolutions or less. May be energized, and the synchronous motor may be energized based on the output signal of the speed generator when the rotational speed of the synchronous motor exceeds a predetermined rotational speed.

[0044]

According to the synchronous motor control method of the first or second aspect, the synchronous generator is controlled by using the output signal of the rectification sensor and the output signal of the speed generator.
The control device for the synchronous motor can be manufactured at low cost.
Further, since the rectification sensor and the speed generator are used in such a manner as to complement each other's drawbacks, it is possible to obtain a resolution comparable to that of the encoder. In addition, the rectification sensor and the speed generator can use those with heat resistance, and it is possible to obtain the one with excellent heat resistance as the control device of the synchronous motor, which can obtain high reliability and can be used even in high temperature environment. It will be possible.

According to the synchronous motor control method of the third aspect, in addition to the effect of the first aspect, in the energization control of the synchronous motor by the output signal of the speed generator, the zero phase corresponding to the reference position of the rotor. Although a signal is required, this zero-phase signal can be obtained from the output signal of the rectification sensor, and a dedicated zero-phase signal detection means is unnecessary, resulting in low cost. According to the synchronous motor control method of the fourth aspect, in addition to the effect of the first aspect, the circuit for producing the zero-phase signal can be manufactured at low cost.

According to the synchronous motor control method of the fifth aspect, the same effect as that of the first aspect can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a synchronous motor control device for carrying out a synchronous motor control method according to an embodiment of the present invention.

FIG. 2 is a timing chart of each part of the control device for the synchronous motor shown in FIG.

FIG. 3 is a timing diagram of each part of the control device for the synchronous motor shown in FIG.

FIG. 4 is a schematic diagram showing the structure of a speed generator used in the control device for the synchronous motor of FIG.

5 is a schematic diagram showing the structure of a commutation sensor used in the control device for the synchronous motor of FIG.

6 is a waveform diagram showing an example of an output signal waveform of the rectification sensor of FIG.

FIG. 7 is a block diagram showing a configuration of a control device for a synchronous motor that implements a conventional method for controlling a synchronous motor.

[Explanation of symbols]

 1 Synchronous Motor 2 Rectifier Sensor 3 Speed Generator 4 Voltage Judgment Circuit 5 Gate 6 Gate 7 Gate 8 Waveform Memory 9 Rectangular Wave Address Generation Circuit 10 OR Gate 11 Digital / Analog Converter 12 Digital / Analog Converter 13 Signal Synthesizer 14 Driver 15 Up-down counter 16 Zero-phase pulse generation circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomokuni Iijima 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. An output signal is taken out from a commutation sensor and a speed generator attached to the synchronous motor, and the synchronous motor is controlled based on the output signal of the commutation sensor when the rotational speed of the synchronous motor is a low speed rotation of a predetermined rotational speed or less. A method for controlling a synchronous motor, wherein energization is controlled, and the synchronous motor is energized based on an output signal of the speed generator when the rotational speed of the synchronous motor exceeds the predetermined rotational speed. 2. An output signal is taken out from a rectification sensor and a speed generator attached to a synchronous motor, and when the output signal of the speed generator becomes a low level below a predetermined level, the output signal is output based on the output signal of the rectification sensor. Energizing control of the synchronous motor, and energizing control of the synchronous motor based on the output signal of the speed generator when the output signal of the speed generator becomes a high level exceeding a predetermined level. Control method. 3. The synchronous motor according to claim 1, wherein a zero-phase signal in energization control of the synchronous motor based on the output signal of the speed generator is created with reference to the output signal of the rectification sensor. Control method. 4. The zero-phase signal is generated at a timing corresponding to a phase of 30 degrees of the reference phase.
The control method of the synchronous motor as described in the above. 5. The control signal generated based on the output signal of the rectification sensor is a rectangular wave signal, and the control signal generated based on the output signal of the speed generator is a sine wave signal. A method for controlling the synchronous motor described.