JPS6240956B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a current control device for a thyristor motor that controls a current in a compensation field winding of the thyristor motor.

A conventional current control device for a thyristor motor of this type is shown in FIG. In this FIG. 1, 101 is the armature of the synchronous motor 100;
02 is a main field winding of the synchronous motor, 103 is a compensation field winding of the synchronous motor, 104 and 105 are a distributor and a finger speed generator connected to the rotor shaft of this synchronous motor, 106 and 108 107 is a reactor connected between the converter 106 and the inverter 108; 109 is a converter that supplies DC power to the main field winding 102; 110 is a converter that supplies DC power to the main field winding 102; a converter 111 that supplies bidirectional polarity DC power to the compensation field winding 103;
112 is a speed control device that amplifies the deviation between the speed command NREF and the output signal of the finger speed generator 105, and 112 is a current detector 11 that detects the output signal of this speed control device 111 and the DC current of the inverter 108.
a current control device that amplifies the deviation from the output signal of 8;
113 is a gate control device which converts the output signal of this current control device 112 into a gate signal and supplies it to the converter 106; 114 is the gate control device
an inverter gate logic device 115 for converting the output signal of 4 into a gate signal of the inverter 108;
116 is a logic circuit that supplies a current throttling command to the current control device 112 based on the output signal of the inverter gate logic device 114 and the finger speed generator 105; A current control device 117 amplifies the deviation from the output signal of a current detector 119 that detects the current of the magnetic winding 103; 117 is this current control device 116;
This is a gate control device that converts the output signal of the converter 110 into a gate signal and supplies the converted gate signal to the converter 110.

Next, the operation of the above-mentioned thyristor motor current control device will be explained below. When the speed of the synchronous motor 100 is low, the induced voltage in the armature winding 101 is small, so the inverter 108 generally commutates using intermittent current control, and when the speed of the synchronous motor 100 becomes low, the induced voltage increases, so this induced voltage Commute. The synchronous motor 100 has a speed control device 111
If there is a deviation in the speed input, this is amplified and a current command is output.
This current command is given to current control devices 112 and 116, which control the currents of armature winding 101 and compensation field winding 103, respectively. This operation of the compensation field controls the armature reaction caused by the current flowing through the armature winding 101, and the current in the compensation field winding 103 is in a comparative relationship with the current in the armature winding 101. controlled as follows. The timing of the gate signal of inverter 108 is obtained by distributor 104 and inverter gate logic device 114 and is synchronized with the induced voltage of synchronous motor 100.

During low-speed operation, the inverter 108 performs commutation as follows by intermittent current. The logic circuit 115 determines the low speed based on the speed detection signal,
When the inverter gate logic device 114 provides a signal that matches the timing of the gate signal provided to the inverter 108, the current control device 11
Give a current throttling command to 2. At this time, current control device 112 operates to delay the phase control angle of converter 106, and makes the current in armature winding 101 zero. After about 10ms, the current throttling command of the logic circuit 115 is turned off, and the current control device 11
2 is controlled to return to the current value immediately before current throttling. This operating waveform will be explained with reference to FIG. When commutating from the U-phase to the V-phase of the inverter 108, the logic circuit 115 synchronizes with the rise time of the V-phase gate signal of the inverter 108.
The output of is at zero level and the armature current is attenuated to zero. At this time, the current in the compensation field winding is also attenuated by the magnetic coupling on the armature side. When the time change of this current is large, a voltage change represented by Ldi/dt occurs in the compensation field winding, and this is superimposed on the output voltage of converter 110, so that the voltage of the compensation field winding becomes an overvoltage. Although L is omitted in FIG. 1, it is an inductance component of the AC input power source of the converter 110 and the reactor within the converter 110.

Since the conventional compensating field current control device is configured as described above, the compensating field winding becomes overvoltage during intermittent commutation of the inverter 108, and it is necessary to increase the withstand voltage of the compensating field winding. However, there were also drawbacks such as the need to increase the withstand voltage of the converter 110.

The present invention has been made to eliminate the drawbacks of the above-mentioned conventional devices, and includes a compensating field current control device that synchronizes with the intermittent commutation of the inverter 108.
It is an object of the present invention to provide a current control device that can lower the voltage of a compensation field winding by giving a current throttling command.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 3 to 5 of the accompanying drawings. Figures 1 and 2
In Fig. 3, parts that are the same as those in the figure are designated by the same reference numerals.
The current control device 216 amplifies the deviation between the output signal of the speed control device 111 and the output signal of the current detector 119 that detects the current of the compensation field winding, and also amplifies the output signal of the logic circuit 115 during intermittent commutation of the inverter 108. Accordingly, the current reduction operation of the compensation field winding is performed in synchronization with the reduction of the armature current. A specific circuit of this current control device will be explained with reference to FIG. In FIG. 4, 216a is an operational amplifier;
216b and 216c are each speed control device 11
1 and an input resistor of the operational amplifier 216a connected to the output signal of the current detector 119; 216d is a field effect transistor FET that operates to short-circuit the input and output terminals of the operational amplifier according to the output signal of the logic circuit 115; 216f is a feedback resistor and capacitor of the operational amplifier 216a.

The current control device 216 performs proportional-integral operation as shown in the circuit example of FIG.
The output signal of the compensation field winding 10 is set as the current command.
Control the current of 3. At the time of intermittent commutation of the inverter 108, the output signal of the logic circuit 115 is at zero level and the armature current is attenuated to zero, while the output signal of the logic circuit 115 is the current control device 216 of the compensation field. The output of this current control device 216 becomes zero. The phase angle α of this gate signal lags behind 90°, and the voltage of converter 110 becomes negative. The operating waveforms in this case are shown in FIG. A case is shown in which commutation occurs from the U phase to the V phase of the inverter 108, and the output signal of the logic circuit 115 becomes zero level at the same time as the V phase gate signal rises, and during the period when this signal is at zero level, the compensation field Because the output voltage of the magnetic converter 110 is reduced to a negative level, due to the attenuation of the armature current,
The effect of magnetic coupling occurs in the winding of the compensation field.
Even if the Ldi/dt component voltages are added, the voltage level can be reduced compared to the conventional voltage level.

As described above, according to the present invention, the timing signal for intermittent commutation is applied to the current control device of the armature and at the same time to the current control device of the compensation field to perform the current throttling operation. With this configuration, it is possible to obtain a current control device for a thyristor motor that can lower the generated voltage, has high reliability, and is thus economically superior.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing a current control device for a thyristor motor, FIG. 2 is a diagram of its operation waveforms, FIG. 3 is a circuit configuration diagram showing a current control device for a thyristor motor according to an embodiment of the present invention, and FIG. The figure is a specific circuit diagram of this current control device, and FIG. 5 is an operating waveform diagram of this current control device. 100...Synchronous motor, 101...Armature winding, 102...Main field winding, 103...Compensation field winding, 104...Distributor, 105...Finger speed generator, 106...Electric machine Child converter, 107...
Reactor, 108... Armature inverter, 1
09... Main field converter, 110... Compensation field converter, 111... Speed control device, 11
2... Current control device for armature, 113... Gate control device, 114... Inverter gate logic device, 115... Logic circuit, 116, 216... Current control device for compensation field, 117... Gate control device , 118... Current detector, 119... Current detector, 216a... Operational amplifier, 216b, 216
c, 216e...Resistor, 216f...Capacitor, 216d...FET. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A thyristor motor separately provided to control the armature current and compensation field current of the synchronous motor by an output signal of a speed control device for the synchronous motor having a main field winding and a compensation field winding. In the current control device, when the synchronous motor is in intermittent commutation operation, an intermittent commutation timing signal causes the current control device of the armature and the compensation field to synchronously perform a current throttling operation. Current control device for thyristor motor.