JPH0785672B2 - Three-phase synchronous motor speed controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a speed control device for a three-phase synchronous motor such as a brushless servomotor.

[Conventional technology]

The brushless motor is similar to a general permanent magnet type synchronous machine, and is composed of a fixed armature and a rotating magnet field.
A permanent magnet is used for the field. In a brushless motor, the positions of the armature and the magnet field of a general magnet field type DC servo motor are reversed inside and outside, and the rectification mechanism by the brush and commutator has a rotor position detection mechanism and a semiconductor. It was replaced by a switch.

The torque generation principle of the brushless motor will be described below.

As with DC motors, the brushless motor torque is such that the armature magnetomotive force and rotor magnetic flux always maintain an orthogonal relationship.
Obtained by supplying current to the armature winding. Since the magnetic flux of the rotor can be indirectly observed in the induced voltage waveform of the armature winding according to Faraday's law and Lenz's law, the reference position of the rotor position detection mechanism described above should be determined according to the induced voltage waveform. Therefore, the direction of the armature magnetomotive force to be taken can be determined. Since the armature winding of a brushless motor is usually a three-phase balanced winding, the rotation of the rotor causes each armature winding to have a displacement angle (electrical angle) from the reference position of the rotor. An induced voltage with a phase difference of 120 degrees is generated.
The motor magnetic circuit is designed so that the magnetic flux intersecting the armature conductors of each phase is distributed in a sinusoidal shape in the circumferential direction. That is, the maximum value of the magnetic flux density of each phase is B _u , B _v , B _w
If B _m and the displacement angle of the rotor are θ _r , then B _u = B _m · sin (θ _r ) …… (1) B _v = m _m · sin (θ _r −120 °) …… (2) B _w = B _m · sin (θ _r −240 °) (3) The generated torque T of the brushless motor is the sum of the generated torque of each phase, and from Fleming's law, Is shown (however, K: constant). Where the armature current of each phase
By making I _u , I _v , and I _w sinusoidal and matching the phase information with the phase of each magnetic flux density, T ∝sin ² θ _r + sin ² (θ _r −120 °) + sin ² (θ _r −240
°) = 1.5 (5) and the generated torque T depends only on the product of the maximum values of the armature current and the magnetic flux density, and is irrelevant to the rotor displacement angle θ _r .

Next, a conventional speed control device for a brushless servomotor will be described with reference to FIG.

The speed command circuit 1 generates a speed command signal corresponding to a predetermined speed command. The speed compensation circuit 2 performs a PID compensation calculation on the speed deviation signal obtained from the speed command signal from the speed command circuit 1 and the speed feedback signal from the speed detection circuit 9 to generate a current command signal. The three-phase current command circuit 3 generates three-phase current command signals for three armature winding phases from the current command signal from the speed compensation circuit 2 and the displacement angle signal from the displacement angle detection circuit 8. The current compensating circuit 4 is a current for three phases obtained from the three-phase current command signal from the three-phase current command circuit 3 and the current detection signal for the three phases of the armature winding detected by the three-phase current detection circuit 6. Performs PID compensation calculation on the deviation signal to generate a three-phase voltage command signal. The amplifier circuit 5 amplifies the three-phase voltage command signal from the current compensation circuit 4 and drives the three-phase synchronous motor 7.
Further, in the displacement angle detection circuit 8 and the speed detection circuit 9, each sensor unit is connected to the rotor shaft of the three-phase synchronous motor 7, and the displacement angle θ _r and the speed are detected. Respectively detected.

[Problems to be solved by the invention]

By the way, in order to prevent the torque ripple of the three-phase synchronous motor, it is necessary to exactly match the phase of the armature current with the phase of the magnetic flux density as described above. Since the phase of the magnetic flux is determined by the rotation angle of the armature, the phase change of the magnetic flux also increases during high speed rotation. Therefore, control of the armature current requires high-speed response.

Control of the armature current in the conventional device is performed by the PID control of the current compensation circuit as described above.
The response was not good enough to suppress the ripple sufficiently, and therefore a higher performance control system was desired.

In consideration of such a point, the present invention is excellent in high-speed response,
It is an object of the present invention to provide a speed control device for a three-phase synchronous motor with less torque and ripple.

[Means for solving problems]

Although the conventional current control system determines the armature winding applied voltage (three-phase voltage command signal) by PID compensation calculation, the present invention has an equivalent circuit of the armature winding in the current control system. The equivalent circuit predicts the voltage drop and induced voltage of the inductance and DC resistance, and calculates and outputs the armature winding applied voltage such that the armature current matches the armature current command value. In the present invention, in order to reduce the scale of the armature winding applied voltage calculation circuit, the detector and the control calculation circuit are configured in two phases even though the motor is a three-phase synchronous motor.

FIG. 1 is a diagram showing the configuration of the first invention of the present application, in which 1 is a speed command circuit, 2 is a speed compensation circuit, 11 is a two-phase current command circuit, 12 is an inductance voltage drop prediction circuit, and 13 is a DC resistance voltage. Fall prediction circuit, 14 induced voltage prediction circuit, 15 two-phase voltage command circuit, 16 two-phase three-phase conversion circuit, 5 amplification circuit, 17 two-phase current detection circuit, 7 three-phase synchronous motor, 18 Two-phase displacement angle detection circuit, 9
Is a speed detection circuit. The two-phase displacement angle detection circuit 18 and the sensor section of the speed detection circuit 9 are both connected and driven to the rotor shaft of the three-phase synchronous motor 7.

The speed command circuit 1 generates a speed command signal corresponding to a predetermined speed command.

The speed compensation circuit 2 performs a PID compensation calculation on the speed deviation signal obtained from the speed command signal and the speed feedback signal from the speed detection circuit 9 to generate a current command signal. Two-phase current command circuit
Reference numeral 11 generates a two-phase current command signal based on the current command signal and the two-phase rotation angle signal from the two-phase displacement angle detection circuit 18. The inductance voltage drop prediction circuit 12 calculates the two-phase voltage drop value due to the armature winding inductance from the two-phase current command signal, the two-phase current feedback signal from the two-phase current detection circuit 17, and the armature winding two-phase inductance value. Predict. The DC resistance voltage drop prediction circuit 13 predicts the two-phase voltage drop value due to the DC resistance of the armature winding from the two-phase current command signal or the two-phase current feedback signal and the DC resistance value of the armature winding. Induced voltage prediction circuit
14 predicts the armature winding two-phase induced voltage value from the two-phase rotation angle signal from the two-phase displacement angle detection circuit 18. The two-phase voltage command circuit 15 includes a two-phase voltage drop signal by the two-phase inductance of the inductance voltage drop prediction circuit 12, a two-phase voltage drop signal by the two-phase DC resistance of the DC resistance voltage drop prediction circuit 13, and an induced voltage prediction circuit 14. A two-phase voltage command signal is generated from the two-phase induced voltage signal. The two-phase / three-phase conversion circuit 16 converts the two-phase voltage command signal from the two-phase voltage command circuit 15 into a three-phase voltage command signal. The amplifier circuit 5 amplifies the three-phase voltage command signal from the two-phase / three-phase conversion circuit 16 and drives the three-phase synchronous motor.

Further, FIG. 2 is a diagram showing a configuration of a second invention of the present application, and the same portions as those in FIG. 1 are denoted by the same reference numerals. Therefore, redundant description will be omitted. Reference numeral 21 is a two-phase speed command circuit, which generates a two-phase speed command signal from the speed command signal from the speed command circuit 1 and the two-phase rotation angle signal of the two-phase displacement angle detection circuit 18. The differentiating circuit 23 differentiates the two-phase rotation angle signal from the two-phase displacement angle detecting circuit 18 to generate a two-phase velocity feedback signal. The two-phase speed compensating circuit 22 performs a p-compensation operation on the speed deviation signal obtained from the two-phase speed command signal from the two-phase speed command circuit 21 and the two-phase speed feedback signal from the differentiating circuit 23 to generate a two-phase current command signal. To generate. The induced voltage prediction circuit 24 predicts the armature winding two-phase induced voltage value from the two-phase speed command signal from the two-phase speed command circuit 21.

[Action]

In explaining the operation, the theory underlying the present invention will be described first.

FIG. 3 shows an equivalent circuit of the armature winding for one phase of the three-phase synchronous motor. Where r ₁ is the armature winding DC resistance, L ₁ is the armature winding inductance, e _u is the induced voltage in the u-phase armature winding, and V _u is the u-phase armature winding applied voltage. , I _u represents the u-phase armature winding current, respectively. Similarly, e _v , e _w , V _v ,
V _w , I _v , and I _w are the v-phase w-phase induced voltage, the applied voltage, and the winding current, respectively.

The armature winding voltage equation for a three-phase synchronous motor is (However, p: differential operator)

The induced voltage of each phase is given by the rotor displacement angle θ _r and the induced voltage constant K _E. Becomes That is, in order to flow the armature currents I _u , I _v , and I _w , the armature applied voltage V _u , which satisfies the formulas (6) and (7),
It is _sufficient to apply V _v and V _w . In the present invention, the calculation for obtaining the armature applied voltage is performed by the two-phase circuit in order to reduce the scale of the arithmetic circuit. In order to convert the equations (6) and (7) into the three-phase / two-phase transformation defined in FIG. 4, the coordinate transformation matrix With, Becomes Also in this case, needless to say, V _α and V _β may be applied in order to flow the armature currents I _α and I _β .

Where I _α ^* , I _β ^* are two-phase current command signals, V _α ^* , V _β ^* are two-phase voltage command signals, and I _α , I _β are two-phase current feedback signals, equation (8), (11 ) From the formula And the inductance term is Can be approximated (however, ΔT: minute time) Can be expressed as That is, the two-phase current command signal I _α
^* , I _β ^* , two-phase current feedback signals I _α , I _β and two-phase velocity feedback information If it is found that the optimum two-phase voltage command signals V _α ^* and V _β ^* to be applied to the armature winding can be obtained from the equation (14).

Here, since the two-phase current feedback signals I _α and I _β are values in two phases and cannot be directly detected, the three-phase current detection values
It is calculated from I _u , I _v , and I _w by the equation (10).

That is, using the property that the sum of the three-phase currents becomes zero, The two-phase voltage command signals V _α ^* and V _β ^* obtained here are values in two phases and must be three-phase voltage command signals. This is calculated by the following equation using a two-phase to three-phase conversion matrix. Ask.

In the present invention, the inductance voltage drop prediction circuit 12 and the DC resistance voltage drop prediction circuit 13 predict the inductance and DC resistance voltage drop of the armature winding, respectively, and the induced voltage prediction circuit 14 or 24 predicts the armature winding. Since the induced voltage is predicted, the armature current matches the armature current command value.

〔Example〕

FIG. 5 shows the configuration of an embodiment of the present invention. The speed command circuit 1 divides the DC power supplies 101 and 102 by the variable resistor 103 and outputs a speed command signal V _ref according to a predetermined speed command. The speed compensation circuit 2 receives the speed command signal V _ref and the speed feedback signal from the speed detection circuit 9. And an PID calculator 106 that performs a PID compensation calculation on the deviation signal to generate a current command signal. The two-phase current command circuit 11, the current command signal and the two-phase angle signal from the two-phase displacement angle detection circuit 18 And multipliers 111 and 112 for respectively generating the two-phase current command signals I _α ^* and I _β ^* . The inductance voltage drop prediction circuit 12 includes adders 121 and 122 for taking a two-phase current deviation between the two-phase current command signals I _α ^* , I _β ^* and the two-phase current feedback signals I _α , I _β from the two-phase current detection circuit 17. , To the two-phase current deviation And multipliers 123 and 124 for outputting a two-phase voltage drop signal due to the armature winding inductance. The DC resistance voltage drop prediction circuit 13 uses the two-phase current command signals I _α ^* , I _β ^*.
Alternatively, it comprises multipliers 131 and 132 for multiplying the two-phase current feedback signals I _α and I _β by the value of the armature winding DC resistance value r ₁ and outputting a two-phase voltage drop signal due to the armature winding DC resistance. The induced voltage prediction circuit 14 is a two-phase rotation angle signal. Are differentiated by differentiators 141 and 142 respectively, and a two-phase velocity feedback signal is obtained. Are generated and multiplied by K _E and −K _E in multipliers 143 and 144, respectively, and a two-phase induced voltage signal in the armature winding is output. The two-phase voltage command circuit 15 is composed of adders 151, 152, 153, 154, and adds the output signal of the inductance voltage drop prediction circuit 12, the output signal of the DC resistance voltage drop prediction circuit 13, and the output signal of the induced voltage prediction circuit 14, Two-phase voltage command signals V _α ^* and V _β ^* are output. The two-phase / three-phase conversion circuit 16 includes multipliers 161, 162, 163,
The multiplier 161 is composed of adders 164 and 165, and V _α ^* of the two-phase voltage command signal is calculated in the multiplier 161. The three-phase voltage command signals V _u ^* also the output to multiplier 162 V _alpha ^* Then, the multiplier 163 calculates V _β ^* of the two-phase voltage command signal To do. In the adder 164, the outputs of the multipliers 162 and 163 are added to output V _u ^* of the three-phase voltage command signal, and in the adder 165, the outputs of the multiplier 161 and the adder 164 are inverted and added to obtain the three-phase voltage. Output V _w ^{* of the} command signal.

That is, the two-phase / three-phase conversion circuit 16 performs the operation of the above-mentioned equation (16). The amplifier circuit 5 includes an amplifier 16 for three phases.
6,167,168, and three-phase voltage command signals V _u ^* , V _u
Amplifies ^* , V _w ^* and drives the three-phase synchronous motor 7. The two-phase current detection circuit 17 generates two-phase current feedback signals I _α and I _β from the three-phase current feedback signals I _u , I _v and I _w obtained from the current detectors 171, 172 and 173 for each phase. That is, in the adder 174, I
_The value obtained by subtracting I _w from _v is multiplied by the multiplier 175. Then, I _β of the two-phase current feedback signal is output. In the multiplier 176 I _u Then, I _α of the two-phase current feedback signal is output.

That is, the calculation of equation (15) is performed. The two-phase displacement angle detection circuit 18 uses a two-phase excitation, two-phase output type resolver 181. The oscillator circuit 182 generates a clock signal for generating a resolver excitation signal. 90 ° phase difference generator 18
3 inputs the clock signal and outputs a two-phase signal which is 90 degrees out of phase with each other and which is equal to the excitation signal frequency ω / 2π. Bandpass filters 184 and 185 have center frequency ω / 2π
Is a band-pass filter for removing the harmonic components of the two-phase signal to obtain two-phase sine waves sinωt and cosωt. The two-phase sine wave is amplified by the amplifiers 186 and 187, and excites the primary winding of the resolver. The resolver 181 is a primary winding of the excitation signal in the secondary winding is excited by a sine wave of peripheral such as a two-phase with several omega / 2 [pi displacement angle theta _r in the phase-modulated two-phase sine wave signal sin (omega
t−θ _r ), cos (ωt−θ _r ) is induced.

The multiplier 191 multiplies the signals cos ωt and sin (ωt−θ _r ) and the multiplier 192 multiplies the signals sinωt and cos (ωt−).
θ _r ) is multiplied, and the adder 193 adds these multiplication results. That is, sin ωt · cos (ωt−θ _r ) −cos ωt · sin (ωt−θ
_r ) = sin θ _r (17) is obtained, and the addition result is sin θ _r . Similarly, the multiplier 194 multiplies the signals sinωt and sin (ωt−θ _r ) by the multiplier 195, and the signals cosωt and cos (ωt−θ _r ) by the multiplier 196. The adder 196 adds the multiplication results. That is, cos ωt · cos (ωt−θ _r ) + sin ωt · sin (ωt−θ
_r ) = cos θ _r (18) is obtained, and the addition result is cos θ _r .

Multipliers 197 and 198 respectively obtain the obtained two-phase sine waves sin θ _r and cos θ _r And two-phase sine wave Output as. The speed detection circuit 9 is composed of a speed generator or the like, but it is also possible to generate a speed feedback signal by an electronic circuit from the signal of the two-phase displacement angle detection circuit 18.

FIG. 6 shows the velocity feedback signal from the signal of the two-phase displacement angle detection circuit 18. 2 shows a circuit configuration for generating In FIG. 6, differentiators 201 and 202 respectively differentiate the two-phase sine waves sin (ωt−θ _r ) and cos (ωt−θ _r ) induced in the secondary excitation winding of the resolver 181. To generate. The signal at the multiplier 203 And cos (ωt−θ _r ) are multiplied and the multiplier 204 outputs the signal And sin (ωt−θ _r ) are multiplied. The adder 205 subtracts the output signal of the multiplier 204 from the output signal of the multiplier 203. Generate a signal.

The adder 206 subtracts the output of the adder 205 from the ω signal set by the constant setter 207. Generate a signal.

With the above configuration, an applied voltage is applied to the armature winding of the three-phase synchronous motor 7 so that the armature current matches the armature current command value.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 7, a two-phase speed command circuit 21, a two-phase speed compensation circuit 2
2, other configuration except the induced voltage prediction circuit 24, differentiating circuit 23,
Since the operation is the same as in FIG. 5, only the two-phase speed command circuit 21, the two-phase speed compensation circuit 22, the differentiation circuit 23, and the induced voltage prediction circuit 24 will be described.

The two-phase speed command circuit 21 is composed of multipliers 211 and 212, and the speed command signal V _ref from the speed command circuit 1 and the two-phase displacement angle detection circuit
Two-phase rotation angle signal from 18 And from two-phase speed signal To generate. The differentiating circuit 23 is composed of differentiators 231, 232,
Two-phase velocity feedback signal by differentiating each two-phase rotation angle signal To generate. The two-phase speed compensation circuit 22 is a two-phase speed command signal. And two-phase velocity feedback signal To generate a two-phase current command signal. That is, the adders 221, 222 calculate the two-phase speed deviation signal, and the p compensators 223, 2
At 24, a two-phase current command signal is generated from the two-phase speed deviation signal. (Here, the reason why the p compensators 223 and 224 are not PID compensators is that the speed deviation signal includes two-phase rotation angle information.
This is because the two-phase condition collapses when D compensation calculation is performed. ) The induced voltage prediction circuit 24 is a two-phase speed command circuit 21.
Two-phase speed command signal from Is multiplied by K _{E in} multipliers 241, 242, and a two-phase induced voltage signal in the armature winding is output. This is because the speed command signal V _ref can be regarded as rotation angle differential signal information.

With the above configuration, the same effect as that of the first embodiment described above can be obtained.

〔The invention's effect〕

As described above, according to the present invention, in the current control system,
It has an equivalent circuit for the armature winding, and the equivalent circuit calculates and outputs the armature winding applied voltage so that the armature current matches the armature current command value. The responsiveness can be improved.

In addition, since the detector and the control arithmetic circuit are composed of two phases in spite of being a three-phase synchronous motor, the circuit scale can be reduced.

[Brief description of drawings]

1 is a block diagram showing the configuration of the first invention of the present application, FIG. 2 is a block diagram showing the configuration of the second invention of the present application, and FIG.
FIG. 4 is an equivalent circuit diagram of a three-phase synchronous motor, FIG. 4 is a diagram for explaining three-phase / two-phase conversion in the present invention, and FIG. 5 is a speed control device for a three-phase synchronous motor according to an embodiment of the present invention. 6 is a block diagram of a speed detection circuit applicable to the device, and FIG. 7 is a block diagram showing a structure of a speed control device for a three-phase synchronous motor according to another embodiment of the present invention. FIG. 8 is a block diagram showing the structure of a conventional speed control device for a three-phase synchronous motor. 1 ... speed command circuit, 2 ... speed compensation circuit, 5 ... amplification circuit, 7 ... three-phase synchronous motor, 9 ... speed detection circuit, 11
Two-phase current command circuit, 12 ... Inductance voltage drop prediction circuit, 13 ... DC resistance voltage drop prediction circuit, 14, 24 ...
… Induced voltage prediction circuit, 15 …… Two-phase voltage command circuit, 16 ……
Two-phase / three-phase conversion circuit, 17 ... two-phase current detection circuit, 18 ... two-phase displacement angle detection circuit, 21 ... two-phase speed command circuit, 22 ... two-phase speed compensation circuit, 23 ... differential circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masayoshi Nakai Inventor Masayoshi Nakai 2-1-1, Niihama, Arai-cho, Takasago-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory (56) Reference JP-A-55-153286 (JP, A) Kaisho 58-99287 (JP, A)

Claims (2)

[Claims] 1. A speed command circuit for generating a speed command signal corresponding to a predetermined speed command, and a two-phase current feedback signal for detecting an armature winding current of a three-phase synchronous motor to be controlled. A phase current detection circuit, a two-phase displacement angle detection circuit that detects the rotation angle of the rotor of the three-phase synchronous motor, and generates a sinusoidal two-phase rotation angle signal, and detects the rotation angular velocity of the rotor, A speed detection circuit that generates a speed feedback signal, a speed compensation circuit that subtracts the speed feedback signal from the speed command signal, and performs a PID compensation operation on the obtained speed deviation signal to generate a single-phase current command signal, A two-phase current command circuit that generates a two-phase current command signal by multiplying the single-phase current command signal by the two-phase rotation angle signal, and a difference between the two-phase current command signal and the two-phase current feedback signal. Is divided by the predetermined control period information An inductance voltage drop prediction circuit that predicts the change rate of the child current and multiplies the change rate of the armature current by the inductance value of the armature winding to predict the two-phase voltage drop due to the inductance of the electronic machine winding. , A DC resistance voltage drop that predicts a two-phase voltage drop due to the DC resistance of the armature winding by multiplying the DC resistance value of the armature winding by the two-phase current command signal or the two-phase current feedback signal A prediction circuit, an induced voltage prediction circuit that differentiates the two-phase rotation angle signal, and multiplies the differential value by an induced voltage constant value to predict a two-phase induced voltage in the armature winding, and the inductance voltage drop prediction circuit A two-phase voltage command circuit that generates a two-phase voltage command signal by adding the output signal of the DC resistance voltage drop prediction circuit and the output signal of the induced voltage prediction circuit. A two-phase three-phase conversion circuit for converting a phase voltage command signal into a three-phase voltage command signal, and an amplifier circuit for amplifying the three-phase voltage command signal and driving the three-phase synchronous motor. Speed control device for phase synchronous motor. 2. A speed command circuit for generating a speed command signal corresponding to a predetermined speed command, and a two-phase current feedback signal for detecting an armature winding current of a three-phase synchronous motor to be controlled. A phase current detection circuit, a two-phase displacement angle detection circuit that detects the rotation angle of the rotor of the three-phase synchronous motor, and generates a sinusoidal two-phase rotation angle signal, and the two-phase rotation angle in the speed command signal. A two-phase speed command circuit that multiplies a signal to generate a two-phase speed command signal; a differentiating circuit that differentiates the two-phase rotation angle signal to generate a two-phase speed feedback signal; A two-phase speed compensating circuit for performing a P compensation calculation on a two-phase speed deviation signal obtained by adding and subtracting the two-phase speed feedback signal to generate a two-phase current command signal, the two-phase current command signal and the two-phase current feedback signal Divide the difference between and by the predetermined control period information Inductance voltage drop prediction circuit that predicts the rate of change of armature current and multiplies the rate of change of the armature current by the inductance value of the armature winding to predict a two-phase voltage drop due to the inductance of the armature winding. And a DC resistance voltage drop prediction for predicting a two-phase voltage drop due to the DC resistance of the armature winding by multiplying the DC resistance value of the armature winding by the two-phase current command signal or the two-phase current feedback signal A circuit, an induced voltage prediction circuit for predicting a two-phase induced voltage in an armature winding by multiplying the two-phase speed command signal by an induced voltage constant value, an output signal of the inductance voltage drop prediction circuit, and the DC resistance A two-phase voltage command circuit that generates a two-phase voltage command signal by adding an output signal of the voltage drop prediction circuit and an output signal of the induced voltage prediction circuit, and the two-phase voltage command signal Speed of a three-phase synchronous motor comprising: a two-phase three-phase conversion circuit for converting into a three-phase voltage command signal; and an amplifier circuit for amplifying the three-phase voltage command signal and driving the three-phase synchronous motor. Control device.