JPH03195387A - Individual difference detecting device for field of synchronous motor and torque detector equipped with same device - Google Patents

Abstract

PURPOSE:To obtain an individual difference easily by a method wherein a reference voltage, converted from the rotating angle of the field rotor of a synchronous motor, which is detected by a rotating angle detector, is compared with the value of a DC voltage, converted from a no-load AC voltage induced in an armature coil. CONSTITUTION:A control circuit 10 converts AC into 3-phase AC of VVVF and supplies it to a synchronous motor SM1. The rotating angle signal (pulse signal) theta of the field rotor of said motor SM1 is obtained by a rotating angle detector 11 and is converted by a F/V converter 22 to generate a reference voltage VO. When said motor SM1 is replaced due to failure and the like, a switch 23 is closed and a value E, converted from the AC voltage VU of said motor SM1 upon no-load through AC/DC conversion, is compared with the reference voltage VO by a comparator 25 to monitor a difference VO-E through a monitor 26. When the difference VO-E is larger than an allowable value, flux PHI corresponding to the difference is generated by a flux setter 15 and correcting operation is effected by a flux vector operator 16 based on the rotating angle signal theta. According to this method, the individual difference between the new and old synchronous motors SM1 detected easily and a field flux set value is corrected whereby the detecting accuracy of the detecting value of a torque may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting field individual differences in a synchronous motor, and a torque detector equipped with the same.

[Conventional technology]

Torque detection of synchronous motors, etc. has conventionally been carried out using torque pickup via a joint 3 between the motor shaft of a three-phase synchronous motor (SM) 1 and the load shaft of a load (LOAD) 2, as shown in FIG. 4, for example. 4 is carried out via a mechanical torque detection means, such as by axially connecting the 4 and 10, or by using a load cell 5 as shown in FIG. 6 is an amplification means for amplifying the detection signal.

Torque detection using the above-mentioned l~kpisok amplifier 4 involves detecting torsional torque between the load shaft and the motor shaft in addition to the torque pickup 4. Torque detection using the load cell 5 moves the motor stator in the direction of the arrow. The reaction torque is applied to the load cell 5.
be detected in addition to.

[Problems to be Solved by the Invention] Torque detection using the torque pickup 4, load cell 5, etc. requires mechanical transmission means for transmitting torque in addition to these, so extra space is required.
Since it is mechanically complex, there is an economical problem in that it is expensive, and detection errors are likely to occur due to play, resonance, and pulsating torque of this mechanical transmission means. In robots and the like, there is a problem in that the torque pickup 4 cannot be used in a high-speed electric motor system because it causes a problem in the motion performance of the robot.

The generated l-lux T of the synchronous motor SM is determined by the number of field poles p
, when the field flux is Φ, the armature current is ■, and the field magnetic pole angle is θ, it is expressed as T=kpΦI c, o sθ, so it can be calculated by giving the field flux as a set value, If the torque is determined by calculation, there is no need to use the mechanical transmission means described above, and the above-mentioned problem can therefore be solved.However, in the case of a torque detector that detects torque by calculation, the torque coefficient used for calculation is If it changes, the calculation result will change. For this reason, when a synchronous motor breaks down and is replaced, even if the synchronous motor is of the same type and has the same torque current, there will be variations in the field flux as well as the torque coefficient (normally, (about 2-3%),
There is a problem in that it is difficult to perform high-precision torque control even after replacing the motor, such as when an error occurs in the torque detection value and high-precision torque control is performed using the synchronous motor as an AC servo motor.

The present invention has been made to solve the above-mentioned conventional problems, and is a synchronous motor field individual difference detection device suitable for use in detecting the generated torque of a synchronous motor, which is often used as an AC servo motor, by calculation. It is an object of the present invention to provide a torque detector equipped with this.

[Means to solve the problem]

In order to achieve the above object, the invention according to claim 1 provides a frequency/voltage for detecting an armature induced voltage by inputting an output signal of a rotation angle detector for detecting a magnetic pole angle of a field rotor of a synchronous motor. A converter, an AC/DC converter that converts the no-load induced voltage induced in the armature winding into a DC voltage, a comparator that compares this DC voltage with the output of the frequency/voltage converter and detects the deviation. The invention of claim 2 provides a d-axis field flux signal and a d-axis field flux signal based on an output signal of a rotation angle detector that detects a magnetic pole angle of a field rotor of a synchronous motor and a set value of generated magnetic flux of the magnetic pole. Generates a q-axis field flux signal, generates a d-axis armature ampere turn signal and a q-axis armature ampere turn signal based on the output of a current detector that detects the armature current of the synchronous motor, and generates the d-axis field flux signal. Multiply the value of the q-axis armature ampere turn signal by the value of the q-axis armature ampere turn signal, multiply the value of the q-axis field flux signal by the value of the d-axis armature ampere turn signal, and perform torque detection by adding the above multiplication values. In a torque detector, a frequency/voltage converter manually converts the output signal of the rotation angle detector to detect the speed corresponding to the armature induced voltage, and converts the no-load induced voltage induced in the armature winding into a DC voltage. AC/DC converter to convert,
It has a comparator that compares this DC voltage with the output of the frequency/voltage converter and detects the deviation, and a monitor that displays the output of this comparator, and the set value of the generated magnetic flux of the magnetic pole is corrected based on the monitor display value. This is the configuration that will be used.

[Function] In the invention of claim 1, since the actual measured value of the armature induced voltage during no-load operation at synchronous speed (constant number x number of rotations x field flux) and the voltage reference value are compared by the comparator, When a synchronous motor is replaced, individual differences in field flux can be determined by comparing the deviation between the actual value measured for the synchronous motor and the voltage reference value with that of the old synchronous motor.

The invention of claim 2 includes a monitor that displays the output value of the comparator, so that the value displayed on the monitor for the replaced new synchronous motor is different from the value displayed on the monitor for the first interphase motor. In this case, the set value of the magnetic flux generated by the magnetic pole can be corrected while looking at the displayed value on this monitor.

Further, the torque detector according to the second aspect performs a vector cross product calculation based on the field flux hector and the armature current hector, and detects the generated torque (instantaneous value) of the synchronous motor.
The mechanical transmission means described above is not required, and the torque generated by the synchronous motor can be detected with high accuracy.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, 10 is a control circuit, which together with a rotation angle detector 11 and a rotating field type synchronous motor SM constitutes a brushless synchronous motor.
The armature winding of the synchronous motor SM through 2 IU, 1■, I
Supply 3-phase AC power to W. The rotation angle detector 11 is a detector that detects the rotation angle of the magnetic poles N and S of the field rotor (permanent magnet) IF, rotates in synchronization with the field rotor IF of the synchronous motor SM, and generates a rotation angle signal ( Pulse signal) θ is sent. 13 is the armature winding IU, 1■, I of the synchronous motor SM
This is a current detector DCCT (the l-phase portion is shown) that detects currents iu, iv, and iw (hereinafter collectively referred to as 1a) supplied to W.

14 is a torque detector, which includes a field flux setting device 15, a magnetic flux hector calculator 16, a 3-phase/2-phase converter 17, and a multiplier 1.
8.19, it is equipped with an adder 20.

21 is a synchronous motor field individual difference detection device, which includes a frequency/voltage converter (F/V converter) 22, a switch 23, an AC/DC converter (A C70C converter) 24, and a comparator 2.
5. It is equipped with a monitor 26.

The control circuit 10 determines the speed of the synchronous motor SM or 1-
A control circuit that controls the torque to the value commanded by the speed command S" or the 1-luke command '1", which converts the power of the AC power source AC into DC and then converts it into three-phase AC with variable voltage and variable frequency. It has a converter and its control device, and the control device takes in the rotation angle signal θ, creates a phase signal whose phase matches the rotation angle signal θ, and controls the current ia output by the power converter. The power converter is controlled so that the instantaneous value of becomes a three-phase AC having a phase based on this rotation angle θ, and feedback control is performed to make the current ia follow the command value.

The field flux setting device 15 of the torque detector 14 is a setting device for setting the value of the magnetic flux Φ generated by the permanent magnet IF, and is a setting device for setting the value of the magnetic flux Φ generated by the permanent magnet IF.
. The value of the magnetic flux ΦF measured at C0 is set as the reference magnetic flux.

The magnetic flux vector calculator 16 inputs the magnetic flux ΦF and the rotation angle signal θ, and calculates a rotating field on a stationary orthogonal coordinate system (d-axis and q-axis shown in FIG. 3) with the rotation center of the field rotor IF as the origin. A two-phase vector signal of the magnetic flux vector @F” is generated.

GdF−ΦF cosθ・・・・・・・・・・・・(1
)ΦqF=ΦFsinθ・・・・・・・・・・・・(2
) However, θ=ωt, ω: The angular velocity three-phase two-phase converter 17 inputs the output of the current detector 13, and the armature ampere turn (rotation vector) set on the above coordinate system. The following two-phase vector signal is generated.

IHdA=N ・IA cos (ωt + −−1ψ′) ・・(3)π [HqA=N ・IA sin , ((
11t + + ψ) ・ ・
(4) However, N-16-HA: To armature ampere turn ■ Double palm current hector IA: Armature current maximum amplitude N: Number of turns of armature winding ψ: Phase difference angle synchronous motor field individual difference detection device 21 F/V converter 22
inputs a rotation angle signal (pulse signal) θ and converts it into a voltage Vo (which becomes a reference voltage) proportional to the rotation angle signal (pulse signal). The switch 23 is a switch that is turned on during no-load operation of the synchronous motor SM. The A C/DC converter 24 converts the no-load induced voltage V of the armature winding IU via the switch 23.
Input u and convert it to DC voltage E. The comparator 25 compares the reference voltage Vo with the actually measured DC voltage E, and
Sends the deviation Δ-■o-E of E with respect to o.

The monitor 26 displays the value of this deviation Δ.

Now, assume that the synchronous motor SM is a lossless motor. Armature ampere turn It (A” = NXIIA
”, the generated torque T” of the synchronous motor SM is T”
=IH8 ”X@F” =(IMFXI
HqA-C+qFXBldA-ΦF-HA co
s ωt ・sin (ωt+ −+ψ)ψF
−HAsjn ωt ・cos (ωt+π =ΦF−I(＾sin n (+ψ)=ΦF −
HAcos ψ−Φ(c)・N−IA co
s ψ・ ・ ・ ・ ・ ・ ・ ・ ・
・(6) The multiplier 20 of the torque detector 14 is r@dFXI
The multiplier 21 calculates 'oqFXHdJ', and the outputs of both multipliers are added by the adder 22, so
The output of this adder 22 provides an instantaneous value T of the torque generated by the synchronous motor SM.

In this way, in this embodiment, the output of the rotation angle detector 11 is processed to generate field flux vectors ΦdF and Φqp,
The output of the current detector 13 is signal-processed to generate armature ampere turn vectors It(da, I(qa), and torque is detected by calculating the cross product of these vectors, so the conventional mechanical transmission means described above is not required. Yes, synchronous motor S
Since the generated torque of M is directly detected, it is possible to perform torque detection with higher accuracy than in the past.

By the way, in order to find out whether or not the set value ΦF of the field flux setting device 15 can be used as is when the synchronous motor SM has failed and is replaced with a new synchronous motor having the same rating as the failed synchronous motor. New synchronous motor S
M is operated with no load and the switch 23 is turned on. As a result, the no-load induced voltage (■) of the new synchronous motor SM is converted into DC, and the output (■0) of the F/V converter 22 and the comparator 25
are compared, and the deviation Δ=■o−E is displayed on the monitor 26. If this deviation Δ is the same value as the deviation Δ previously measured for the failed synchronous motor SM, there is no need to correct the set value ΦF of the field flux setting device 15, but the difference exceeds the allowable range. In this case, the setting value ΦF of the field flux setting device 15 is corrected by the value ΔΦF corresponding to the deviation Δ.

Therefore, according to this embodiment, the field individual difference between the old and new synchronous motors can be known by simply turning on the switch 23, and the field flux set value used for torque calculation can be corrected to match the synchronous motor. Therefore, even if the synchronous motor is replaced, torque detection can be performed with the same high precision as before the replacement.

Since the detected torque value in this embodiment is an instantaneous torque value, it can be used as a feedback value for a high-speed response control system using a synchronous motor SM.

In addition, the torque detector 14 and the synchronous motor field solid state difference detection device 21 are composed of electronic circuits and do not require mechanical transmission means as described above, so they can be made inexpensively and compactly, and the installation space is small. It's small enough.

Furthermore, since the torque calculator is a stationary type and does not require a mechanical transmission means as described above, it can be used to detect the torque of the synchronous motor SM even if it is a high-speed machine, and the torque pickup As such, it is not restricted by rotational speed.

In the above embodiment, the setting value ΦF of the field flux setting device 15 is determined by the deviation Δ−■0−E displayed on the monitor 26.
Although the explanation is that the deviation Δ is manually corrected, a configuration may also be adopted in which this deviation Δ is input to the field flux setter 15 and the set value ΦF is automatically corrected by the value ΔΦF corresponding to the deviation Δ.

〔Effect of the invention〕

As explained above, the field individual difference detection device of the present invention compares the DC conversion value of the no-load induced voltage of the synchronous motor with the voltage reference value, so although it has a simple configuration, it can detect the field individual difference of the synchronous motor. It can be easily detected, and if it is installed in the torque detector, the field flux setting value can be corrected by knowing the individual differences in the field between the old synchronous motor that has been replaced and the new synchronous motor that will be operated from now on. Therefore, it is possible to prevent the detection accuracy of the torque detection value from decreasing due to individual differences in the field of the synchronous motor.

[Brief explanation of drawings]

Fig. 1 is a block configuration diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing the main parts of the above embodiment, and Fig. 3 is a diagram showing the field flux of the synchronous motor and the d- and q-axis vectors of armature ampere turns. 4 and 5 are diagrams for explaining a conventional torque detection method. ■-Synchronous motor, IA-armature winding, IF-rotating field rotor, 11-rotation angle detector, 13-current detector, 14-
Torque detector, 15-field magnetic flux setting device, 16-magnetic flux hector calculator, 17-3-phase/2-phase converter, 18.19-multiplier, 20-adder, 21-synchronous motor field individual difference detection device, 22-F/V converter, 23-switch, 24-AC/
DC converter, 25- comparator, 26- monitor. 1 Fig. 2 1F-m-Rotation 7 Field Loader 11-11 Rotation Error Fig. 3 Fig. 4 4---) Rukbee Waafu. Fig. 5 7--Rotable branch shaft

Claims (2)

[Claims] (1) A frequency/voltage converter that inputs the output signal of a rotation angle detector that detects the magnetic pole angle of the field rotor of a synchronous motor and converts it into a reference voltage proportional to the value of the output signal, which is connected to the armature winding. A synchronous motor field individual difference characterized by having an AC/DC converter that converts the induced no-load induced voltage into a DC voltage, and a comparator that compares the DC voltage with the reference voltage and detects the deviation. Detection device. (2) A d-axis field flux signal and a q-axis field flux signal are generated based on the output signal of a rotation angle detector that detects the magnetic pole angle of the field rotor of the synchronous motor and the generated magnetic flux setting value of the magnetic pole, and synchronization is performed. A d-axis armature ampere turn signal and a q-axis armature ampere turn signal are generated based on the output of a current detector that detects the armature current of the motor, and the value of the d-axis field flux signal and the q-axis armature ampere turn signal are generated. In the torque detector which performs torque detection by multiplying the value of the q-axis field flux signal and the value of the d-axis armature ampere turn signal and adding both of the multiplied values, the rotation angle detector Frequency /
A voltage converter, an AC/DC converter that converts the no-load induced voltage induced in the armature winding into a DC voltage, a comparator that compares this DC voltage with the reference voltage and detects its deviation, and this comparator. 1. A torque detector equipped with a synchronous motor field individual difference detection device, characterized in that the torque detector has a monitor that displays the output of the synchronous motor, and a set value of the generated magnetic flux of the magnetic pole is corrected based on the monitor display value.