JPS60187283A - Speed controller of synchronous motor - Google Patents

Abstract

PURPOSE:To control the speed of a motor without using a rotation sensor by controlling in response to a deviation signal obtained by butting a rotating speed command signal and an inducting electromotive force. CONSTITUTION:Voltage component detectors 9, 10 respectively detect the 2-axis components et', em' of the voltage of a motor 2. The signal em' is applied together with an output command signal 100 from a rotating speed instructing circuit 3 to an adder 11, and input to an oscillator 12, thereby controlling a frequency f1. An amplifier 13 controls a current command im' in response to a deviation between the output signal of the amplifier 11 and the signal et' to maintain the magnetic component phim' at the prescribed value. Further, the output signal from the circuit 3 and the signal et' are butted, the effective current command l* is varied in response to the deviation, thereby controlling the rotating speed in response to the command value.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a speed control device for a synchronous motor, and relates to a speed control device for a synchronous motor that controls the speed of a motor without using a rotation detector. [Background of the Invention] As a speed control device for this type of synchronous motor, the synchronous
Thyristor motor devices are known that control the speed of an electric motor using frequency converter sound. Such a speed control device includes a converter that supplies alternating current with a variable frequency to two synchronous motors, and a converter control device that forms a signal that controls the value (magnitude) and frequency of the alternating current output from the converter. It consists of a circuit.

Such a quick return control device +tf controls the 111111 machine current to a predetermined phase with respect to the induced electromotive force of the electric motor, and also uses a rotation sensor such as a position detector or a speed time detector to control the rotation speed. It is necessary to attach it to the shaft end of the electric motor. However, according to such a speed control device, it is necessary to attach these rotation sensors to a single machine, which increases the number of man-hours and parts, and requires a signal cable from the sensor to the conversion device A.・This resulted in disadvantages such as an increase in the number and number of parts, and a lack of reliability due to the rotation sensor being placed in a bad environment. Purpose] The present invention has been made in view of the above-mentioned disadvantages. 2 The purpose is to provide a speed control device for a tI7J plane that can control the speed of an electric motor without using a rotation sensor. There is a particular thing.

[Summary of the invention]

The present invention is characterized by a deviation signal obtained by comparing a rotational speed command signal and an induced electromotive force (a voltage component that is a fundamental wave component of the motor voltage and has a phase reference signal of the reactive current and a phase difference of 9071). A first means for forming a control signal for controlling the active component of the motor-like current and a voltage component that is the fundamental wave component of the motor voltage and is in phase with respect to the phase reference signal of the reactive current. a second means for forming a control signal for controlling the converter output frequency accordingly;
Calibration voltage command signal! A control signal for controlling the reactive component of the motive current to 1 in accordance with a deviation signal obtained by comparing the phase reference signal of the reactive component current, which is the fundamental wave component of the motive voltage, and a voltage component with a phase difference of 90 degrees. The third means (i-equipment) for forming the motor speed I! is controlled in accordance with the full speed command based on the control signals from these means.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a block diagram showing an embodiment of a speed control device for a synchronous motor according to the present invention. In the figure, 1 is a converter that outputs variable frequency alternating current. This converter 1 is a gate turn-off thyristor.
ff Thyristor (hereinafter referred to as +GTO))
Alternatively, it is configured as a PWM inverter using transistors, diodes, etc. 2 is a periodic motor, which includes two rotors and a stator (in this case, a field winding) 2B; 03 is a rotational speed command circuit; 4 is a motor voltage detection transformer; 5 is a current detector for detecting the instantaneous value of the output current of the inverter 1. Also.

Rotation speed command lo from this rotation speed command circuit 3.

The converter control circuit 6 that has taken in the command 100 is configured to be able to form and output a control signal 200 that controls the magnitude and frequency of the alternating current output from the converter 1 based on this command 100. The converter control circuit 6 includes a rate-of-change limiter 7 for controlling the rate of change of the speed command signal, a speed command signal 100, and a phase reference signal of a reactive current which is a fundamental wave component of the motor voltage, which will be described later. A fast deviation amplification device 8 which takes the deviation* difference between the components having a 90 degree phase difference and amplifies the deviation signal I.
and voltage component detectors 9 and 6 for detecting the fundamental wave component of the motor voltage, which is a component with a phase difference of 90 degrees from the phase reference signal of the reactive current. A voltage component detector 10 for detecting components in the same phase with respect to the phase reference signal of , and output signals of the voltage component detector 10 and rate of change limiter 7 are added to output one frequency command signal (KO2). Adder 1 and frequency command signal 1
An oscillator 12 that outputs a two-phase sine wave signal with a frequency proportional to
: The amplifier 13 outputs: The reactive current command signal i2 from the amplifier 13 and the active current command signal 1' from the amplifier 8 are multiplied by the output signal of the oscillator 1λ. A coordinate converter 1 that outputs a current command pattern signal 1a and one
415, the current command pattern signal and the current detection signal from the t-flow generator 5 are all compared and the GTO of the inverter 1 is established. In addition, the current detector 5, the excavator 15, and the comparator 1
7 is a circuit corresponding to the U phase ratio, and there are similar circuits corresponding to the ■ phase and W phase, but these are omitted from illustration.

Next, the operation of the embodiment configured as described above will be described, but first, the principle of the present invention will be described.

One axis of the orthogonal rotating magnetic field coordinate system of the synchronous motor is ITI'
axis, and the axis perpendicular to it is assumed to be t', and if the horizontal and vertical axes are controlled so that the m' axis coincides with the magnetic flux axis of the motor, the current components 1□' and It' of each axis are They respectively correspond to a reactive current component 11 related to the amount of magnetic flux of the motor and an active current component It related to the torque of the motor.

Therefore, 1t' is controlled by the signal from the speed control circuit,
If im'ffi control is performed using a signal from a voltage control circuit, the motor can be controlled to a predetermined speed and voltage.

By the way, the output frequency (current phase) of the inverter is
In the prior art, the determination was based on the signal of the position detector. However, the present invention instead detects the voltage applied to the motor by using the signal from the pressure detection a4.

The frequency is determined.

Now, the 'ailJ control used in the present invention for aligning the m' axis with the magnetic flux axis of the electric motor will be explained below.

Figure 2 (1) and (ID) show the relationship between the 111' axis and the magnetic pole axis (direct axis) when the effective current command It* from the amplifier 8 is constant and the reactive current command im'' is all 0. It is a characteristic diagram which shows the change characteristic of each electric magnetic flux with respect to a phase difference.

Here, φ□' and φt' are magnetic flux components in the m' and t' axis directions, and φ is the vector composite magnetic flux of φ□Z and 6t/. In addition, Fig. 2 (1) and (It) show the case where the current command i is a positive rated value and the current command 1 is zero, and the short-circuit torque is fully generated during electric operation, and when the operation is performed with no load. It is a figure which shows each case.

The explanation will be given below in order starting from FIG.

In figure (1), the operating point marked with X is - magnetic flux component φt'-
〇・That is, ・This is the normal operating point where the nl' axis coincides with the magnetic flux axis of the motor.

By the way, the sign of It/6 is reversed to positive and negative at this normal operating point. Therefore, when the magnetic flux component φL' is positive, the motor frequency f1 is increased to increase the phase angle θ' from the magnetic pole axis (direct axis) to the m' axis, and conversely, when the magnetic flux component φt' is negative, the motor frequency f1 is increased. - If the phase angle θ' is corrected and controlled in the decreasing direction by lowering the frequency f1f, the operating point will always move to the X mark in the figure - The magnetic flux component φt' = 0 will be maintained 0 Also, the magnetic flux component φ□' ( When φt'=0, it matches the total magnetic flux φr) is controlled to a predetermined value as follows.

That is, since the magnetic flux component φ□' changes according to the current component 1IT1', the magnetic flux component φ□' is detected, and the current component 1' is controlled according to the variation from a predetermined value.
”(j can be kept at a predetermined value.

In the case shown by the mark in FIG. 2, the characteristics are the same as in the case of FIG. 1, and the same control as described above may be performed.

As described above, operation with constant magnetic flux is performed. At this time, the induced electromotive force of electric @ h machine 2 (this is.

- It is a fundamental wave component of the α motive voltage and is a voltage component with a phase difference of 90 degrees from the phase reference signal of the reactive current. ) is proportional to the motor frequency or rotational speed.

The present invention utilizes this phenomenon to detect the induced electromotive force of the electric motor 2 and feed back this detection signal to the speed control circuit to perform speed control.

The operating principle of the present invention has been explained above.

Next, the operation of the circuit shown in FIG. 41, which is an embodiment of the present invention, will be explained.

The voltage component detector 9.10 detects the two-axis components of the motor voltage according to the following formula, that is, the voltage component et/which has a phase difference of 90 degrees with respect to phase criterion No. 13 of the reactive current, and the component em with the same phase. Detect each fc.

Here, Vα=V.

Vβ=-(V, -Vv) 3 8t'; Output signal ej' of the detector 10: Output signal Mu, Vv, Vw of the detector 9: Motor phase voltage cosω, t
: Reactive component current of tJ phase Phase reference signal The above calculation can be realized using, for example, a multiplier and an adder.

Signal em', et'i'! If the influence of the leakage impedance drop of the motor is ignored, the relationship between the above-mentioned φm' and φt' is expressed by the following equation.

That is, a signal corresponding to the magnetic flux component φt' is detected by the signal em'. The signal e tn / is added to the adder 11 together with the output signal of the rate of change limiter 7. At this time, if the signal em' is negative (corresponding to φt'>0), the adder 11
The output signal is large, that is, the inverter output frequency is added with increasing polarity. In this way, the motor frequency f is controlled so that em' = 0 (φt' = o) at all times according to the above-mentioned principle, and the phase angle θ' from the magnetic pole axis to the m' axis is at the normal operating point. Controlled by value.

Also, induced electromotive force et'(φm') and current command I, *
Since there is a proportional relationship, if the induced electromotive force et' is smaller than the predetermined value, the current command 1me increases, and conversely, if the induced electromotive force et/ is less than the predetermined value, the current command tm"
By changing I/c in the decreasing direction, the induced electromotive force eJ can be controlled to a predetermined value. Therefore, in the amplifier 13, a linear relationship is obtained by controlling the current command 1m according to the deviation between the output signal of the amplifier 11 and the signal etf.

k, ω indigo −e t′ = 0 (3)
Alternatively, et'/ω+ = k+ --f4) where *kl: proportionality constant, that is, the magnetic flux component φm'(=et'/ω weight) can be automatically maintained at a predetermined value.

On the other hand, the induced electromotive force et/ is as shown in equation (2).
It is proportional to the magnetic flux component φm' and the angular frequency ωIIC. Therefore, since the magnetic flux component φm' is kept at a constant pupil by the control described above, the induced electromotive force e,/ is proportional to ωl.

Therefore, by comparing the rotational speed command signal from the rate of change limiter 7 with the signal e t/, and changing the effective magnetic current command + ti according to the deviation, control is performed according to the rotational speed production command value. I can do it.

Therefore, according to the present embodiment V, there is an advantage that stable frequency control can be performed without using a rotation sensor, and speed control can be performed once.

FIG. 3 is a circuit diagram showing another embodiment of the present invention. In this embodiment, the converter on the power supply side and the impark on the machine side are connected to the DC circuit #! r'f! : This is an application example to a drive system using a converter connected via

In FIG. 3, the converters include a converter 21 that controls the magnitude of the current supplied to the motor, and a DC reactor 22.
and an inverter 23 that controls the motor frequency and current phase.
It is equipped with Additionally, this embodiment is different from the embodiment shown in FIG.・Electric power is generated based on the output signals from the amplifier 8 and the amplifier 6 13.

A circuit 24 that calculates a current phase command, a phase control circuit 25 that determines commutation timing of the inverter 23 based on a command signal from the calculation circuit 24 based on the output signal from the two-shot four-pin unit 12, and an amplifier. 8 and the amplifier 27 that amplifies the entire deviation from the output signal of the amplification detector 5, and a circuit 2 that determines the firing phase of the converter 21 according to the output signal from the amplifier 27.
It consists of 8.

Next, the operation of the above embodiment will be explained.

The pressure component detectors 9 and 10 detect two components of the voltage of the motor 2, that is, the reactive component 'a 6 according to equation (1) above.
'I- which has a phase difference of 90 degrees with respect to the phase reference signal of ie
The n pressure components e, l and the same phase components er, 1' are detected respectively. Both components e+n'+et' are liili
If we ignore the influence of the 1hVL impedance drop of
A signal corresponding to φt' can be detected by m/. signal e
Output command signal 100 from rotation speed command circuit 3 at m/
◇At this time, e rn
If / is negative (corresponding to φt'> o), adder 1
The output signal of 1 is added with a polarity that is large, that is, the inverter output frequency increases. In this way, according to the JJA principle described above, the frequency f is controlled so that em'=o (φt'=o), and the phase angle θ' from the magnetic pole axis (direct axis) to the Ill' axis 1 is controlled to the value of the normal operating point.

In addition, the induced electromotive force Ct'(φm') and the first flow command Im
is in a proportional relationship, so if the induced electromotive force et/ is smaller than a predetermined value, the current command im is increased, and conversely, if the induced electromotive force et' is less than the predetermined value, it is decreased. By this, it is possible to control the induced electromotive force e, / to a constant value of Jzf. Therefore, by controlling the current command 1m in the amplifier 13 according to the 11 ml difference between the output signal of the amplifier 11 and the signal et/, the magnetic component φm' can be maintained at a predetermined value.

On the other hand, the induced force ′1 r e t/ is proportional to the magnetic component φm′ and the angular frequency ωl, as shown in equation (2),
As mentioned above, by controlling the magnetic component φm'
Since is kept at a constant value, the induced force 'et' is proportional to the angular frequency ω1. Therefore, by comparing the output signal from the rotational speed command circuit 3 and the signal 6 t / and changing the effective component 1st flow command jt* according to the deviation, the 2nd rotational speed can be controlled according to the command value. .

The arithmetic circuit 24 outputs a signal for commanding the phase angle ψ of current 10 with respect to the t' axis shown in FIG. 4, based on the invalid current command signal 11TI* and the effective* current command signal it. The phase angle ψ is expressed by the following formula V.

Based on this phase command No. 100 and the output signal from the excavator 12, the commutation timing of the inverter 23 is set by the phase control circuit 2.
5, and at the same time the deflection angle β is ff.
Ignition is controlled by a signal from 5.

Also, Den+! lh machine 47. The current command value ■ is determined by the calculation circuit 26 from the reactive current command signal Im and the effective current command signal 1t. Increased at 27 rjJ l,
, the firing phase of converter 21 is controlled accordingly to make the current y-node.

Therefore, according to this embodiment, without using a rotation sensor as in the previous embodiment, without step-out during variable speed, stable frequency tlilJ control can be performed, and highly accurate speed control can be performed. @Also, according to this embodiment, there is no one-rotation sensor, so it can be used even in bad environments.

〔Effect of the invention〕

As described above, according to this embodiment, there is no need for a rotation sensor, and highly accurate speed control is possible even when used in a tragic environment.

Figure 1 is a circuit diagram showing an embodiment of the speed control device for a synchronous motor according to the present invention. Figures 2 (I) and (If) provide a detailed explanation of the present invention. FIG. 3 is a circuit diagram showing another embodiment of the invention. FIG. 4 is a vector diagram showing another embodiment of the invention.

1...Converter (inverter), 2...Synchronous motor,
3... Speed command circuit, 4... Voltage detector, 5...
Current detector 6... Replacer control circuit, 8... Speed deviation amplifier.

9.10... Voltage component detector, 11... Adder that outputs a frequency command signal, 12... Oscillator, 13...
Amplifier that outputs a reactive current command signal.

Agent Patent Attorney Tatsuyuki Unuma

Claims (1)

[Claims] 1. A converter that supplies variable frequency alternating current to the synchronous ttJJJ machine, and a converter control that forms a control signal that controls the value of the alternating current output from the converter and the frequency of the alternating current based on the rotation speed command. In the synchronous voltage/single force type speed control device including a circuit, the converter control circuit is configured to: A signal for controlling the magnitude of the active component of the reactive current is formed entirely, and the output frequency of the converter is adjusted according to the motor pressure component that is in phase with the phase reference signal of the reactive current. A signal is formed to variably control the magnitude of the reactive component of the motor current in accordance with the deviation signal between the Kamesukeiso voltage command signal and the induced electromotive force, and the motor speed is adjusted based on these signals. The synchronization device is characterized in that it is configured so that it can be controlled in accordance with the speed command.
Machine speed control device.