JPH0487566A - Method of control of direct-current high voltage generator - Google Patents

Abstract

PURPOSE:To realize an optimal load adjustment by entering a voltage control signal and a current control signal from a voltage setter and a current setter to an analogue OR circuit and controlling ignition of a thyristor at the output side of the analogue OR circuit with one of the signals given priority. CONSTITUTION:A current setter 11 is made with a voltage setter 9 for thyristor control of a DC high voltage generator 4 using the thyristor control method through a function circuit 10 having a current characteristic corresponding to the characteristic of a load 5. The set value of the voltage setter 9 and that of the current setter 11 are compared with a voltage and a current detected from the load 5 respectively to find signals (a) and (b), the signals (a) and (b) are entered to an analogue OR circuit 7, one of the signals is entered to the output side of the analogue OR circuit 7 with priority, and ignition of a thyristor is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a system for simultaneously controlling the voltage and current of a DC high voltage generator, such as a side power supply for an electrostatic precipitator.

[Conventional technology]

In a DC high voltage generator using a thyristor control system, a voltage setting device and a current setting device are respectively provided, and after PI control using the reference values of both membrane regulators and the load applied voltage and current signal from the DC high voltage generator, Voltage control and current control are performed through each regulator, and during on-site adjustments, the reference values (RSF) of the voltage setting device and current setting device are adjusted alternately to adjust to the maximum applied voltage and current of the load. I am doing similar work.

The reason for taking such measures is that for loads that require high voltage, such as electrostatic precipitators, there is no linear relationship between the applied voltage and load current, and to protect the high voltage generating equipment, it is necessary to This is to make the voltage and current follow and reach the final set value.

However, this method requires two setting devices,
Adjustment takes time, and optimal load adjustment is difficult.

[Problem to be solved]

The present invention provides a method for adjusting the maximum applied voltage and current by using one setting device and a function circuit, instead of providing the voltage and current setting devices described above and alternately adjusting the reference values to reach the predetermined maximum applied voltage and current. , and to obtain a control method that can be set to the current, etc.

[Structure of the invention]

In the present invention, a current setting device is configured for a DC high voltage generator using a thyristor control method, and a current setting device is configured via a function circuit having current characteristics according to the characteristics of the load from a voltage setting device used for thyristor control. Each signal is obtained by comparing the respective set values of the voltage setting device and current setting device with the voltage and current detected from the load, and these signals are input to an analog OR circuit, and the above-mentioned signal is input to the output side of the analog OR circuit. This is a control method for a DC high pressure generator characterized by outputting one of the signals with priority to control the ignition of the thyristor.

The present invention will be explained below with reference to embodiments shown in the drawings.

An AC power supply 1 is connected in series to a DC high voltage generator 4 via an anti-parallel silice stack 2 . The high voltage generator 4 is composed of an isolation transformer, a full wave rectifier, etc., converts alternating current into direct current, and forms a load terminal.

RM is a voltage divider that takes out a voltage output control signal Vln representing a voltage equivalent to the DC terminal voltage of the load, and R1 is a current shunt that takes out a control signal 11n equivalent to a DC load current.

Reference numeral 9 denotes a voltage setting device, in which a reference voltage signal Vs corresponding to the voltage to be set can be set.

A control voltage signal of the difference between this voltage signal Vs and the voltage output control signal Vln is obtained by the adder 12, and the difference voltage signal is input to the voltage regulator 8.

On the other hand, Ys from the voltage setting device 9 is the funxidine circuit 1.
0, for example, input to a broken line approximation circuit. The funxidine circuit IO is one in which the voltage and current characteristics of a load, such as those illustrated in 1 to 4 in Fig. 3, are determined in advance by measurement, and the current values corresponding to each voltage value are plotted as RO.
This is what M memorized. 1 to 4 can be switched by the function curve switching circuit 13 according to the connected load.

In this case, when the voltage setter 9 sets the voltage signal Ys on the voltage and current characteristic curve of the target load, for example, the reference current signal Is corresponding to the load current corresponding to the voltage signal Vs is set from the function circuit 10 to the voltage This reference current signal Is and the load current ti are read out in the form of a signal.
A current control signal with a difference of n is determined by an adder +3, and this differential voltage signal is input to a current regulator 11. Note that the maximum value of both the reference voltage signal and the reference current signal is assumed to be IP (for example, IOV).

The output signals a and b from the regulator 8.11 are analog O
Input to R circuit 7.

Now, connect the load 5 to the DC high-voltage terminal, set it in a state where voltage can be applied, set the reference voltage Vs corresponding to a predetermined high-voltage DC voltage on the voltage setting device 9, and energize the Cyrisk stack 2. Then, a voltage control signal Min is generated, and at the same time a control signal tin corresponding to the load current is generated.

If Vs>Vln, a positive signal is input to the voltage regulator 8. On the other hand, the Vs is input to the function circuit IO, the corresponding reference signal Is is taken out, and if ls>11n, a positive signal is input to the current regulator 11, and the adjusted output is input to the analog OR circuit 7. .

The configuration of the analog OR circuit 7 is, for example, as shown in FIG. Voltage regulator 8, current regulator 1
Diodes D1+DQ are connected in the forward direction to the output sides of DI and DQ, respectively, a negative bias voltage is applied to the output sides, and the output from DI or D2 is taken out.

First, input a from voltage regulator 8 is positive, current regulator 11
If the input is positive and a>b, the analog OR circuit 7 outputs a. Based on this a, the pulse control circuit 6 advances the thyristor firing control phase angle to increase the voltage of the DC high voltage generator. On the other hand, assuming that the load current 11n also increases, if a<b then, based on this b, the pulse control circuit θ controls the thyristor in the direction of further voltage increase.

Finally, when Vs is set to a high voltage, the above control is repeated, a becomes zero, and b also becomes zero if a becomes O in advance.
Therefore, Vl is stable here.
n is equal to Vs, tin is equal to Is, and a predetermined voltage and current are maintained.

〔Effect of the invention〕

When the output is generated, by increasing the voltage with the voltage setting device, the output current can be limited to a current according to the load along the Funkuyon curve input in the functs 8 flow circuit IO.

Therefore, output voltage generation and current adjustment can be performed simultaneously.

Furthermore, since the optimum current curve corresponding to the load is input into the ROM in advance, it is possible to perform optimum control of voltage and current according to the load.

[Brief explanation of the drawing]

FIG. 1 shows in block diagram form an embodiment of the invention. FIG. 2 shows an analog OR circuit. FIG. 3 is an illustration of voltage and current characteristics of a load to which the present invention is applied. 1...AC power supply, 2...Sirisk stack, 3.
...Transformer, 4...DC high voltage generator, 5...Load,
6 pulse generation circuit, 7...analog OR circuit, 8...
・Voltage regulator, 9...Voltage setting device, 10...Functu 3F circuit, 11...Current regulator, 13...Funk 7B curve switching circuit. 'l#1 Spiritual Spirit 20 13 Figure Is ■

Claims (1)

[Claims] (1) In a thyristor-controlled DC high-voltage generator, a current setting device is constructed from the voltage setting device used for the thyristor control via a function circuit having voltage and current characteristics according to load characteristics, and the voltage setting device The output of the current setting device and the voltage and current detected from the load are respectively compared, and the voltage control signal and current control signal resulting from the comparison are input to an analog OR circuit, and the analog O
A control system for a DC high voltage generator, characterized in that the firing of a thyristor is controlled by giving priority to one of the signals on the output side of the R circuit.