SU1354369A1 - Method of controlling resonance inverter - Google Patents

Abstract

This invention relates to electrical engineering and can be used in static converters. The aim of the invention is to improve the accuracy of stabilization of a given value of the output frequency of the inverter. The resonant inverter is controlled by determining the value of the 2nd extremum (minimum) of the power gate (thyristor) current and comparing it with the specified minimum allowable value. In case of equality of these values, the frequency of the control pulses arriving at the power gates (thyristors) of the resonant inverter is reduced. 4 il. : ate 4 00 35: O

Description

one

The invention relates to electrical engineering, in particular, to methods of controlling static and resonant frequency converters.

The purpose of the invention is to improve the accuracy of stabilization of a given value of the output power of a resonant inverter.

Figure 1 shows the block diagram of the device that implements the proposed method; 2 shows the t / ibi time diagrams explaining the operation of the device;

13

 Amplitude selector 7, differentiator 10, analog-digital converters Ig 8, 11, and 12, element NOT-OR 9, single pulse generator 14 and electronic switch 13 form an additional control loop operating during operation

on fig.Z - resonant inverter circuit; Fig. 4 shows the variation curves of the output current of the inverter under various operating conditions of the load.

The device contains a power source 1, a resonant inverter 2, made according to the scheme (FIG. 3), the load — a resonant inverter in the modes of which the oscillator increases the equivalent resistance of the circuit 3. To the oscillatory circuit 3 the oscillatory circuit.

Sensor 4 of the output parameter is connected, the stabilization of which is necessary. The output of sensor 4 is connected to the main control loop 5, which controls the resonant inverter. To the resonant inverter 2 is also connected to the sensor 6 current power valves (thyristors), the output of which, respectively, through the amplitude selector 7 and the analog-digital converter 8 is connected to the first input of the HE-IiTM element 9, through the differentiator 10 and the analog-digital converter 1I secondly, the input of the element NOT-OR 9 and through analog-digital converter 12 - with the first digital input of the element AND, which controls the electronic switch 13. The second digital input of the element AND is connected to the output of the element NO-RSHI 9 through the generator .14 alone momentum of (e.g., a monostable multivibrator). The output of the unit 5 is connected directly to the first signal input of the electronic switch 13, the second signal; the first input of which is connected to the output of the amplitude selector 7. The output of the electronic switch 13 is connected to the control unit 15, which controls the inverter power vents1 (thyristors) through pulses adjustable tracking frequency.

The device implements the proposed control method as follows.

-

3543692

While the current curve of the power valves (thyristors) has the form shown in Fig. 4a, the resonant inverter is controlled in order to stabilize a given value of the output parameter (for example, output power) using the method that uses the resonant properties of the load Q-shaped oscillatory circuit 3,

by means of the main control circuit 5.

 Amplitude selector 7, differentiator 10, analog-digital converters Ig 8, 11, and 12, element NOT-OR 9, single pulse generator 14 and electronic switch 13 form an additional control loop operating during operation

 resonant inverter in the modes of increasing the equivalent resistance to analog voltage from the sensor 6 of the power gate current (Fig. 2a)

5 enters the amplitude selector 7, the differentiator 10 and through the analog-digital converter 12 to the first digital input of the electronic switch 13. The voltage from the outputs of the amplitude selector 7 (figv) and the differentiator 10 (fig. 2b) through the analog-digital converters 8 and 11 goes to the corresponding inputs of the element NON-SHSh 9. At the moment when both voltages are equal to zero (the moment reaches 5

0

five

0

five

second extremum of the minimum permissible value), at the output of the NE-IPI element 9, a voltage is formed that triggers the start of the generator 14 of a single pulse.

The output pulse of the generator 14 (FIG. 2g) is fed to the second digital input of the element AND of the electronic switch 13. If there are voltages on both digital inputs of the element AND, the latter switches the electronic switch 13 so that the control unit 15 is connected to an additional control loop. The control voltage coming from the additional control loop affects the control unit 15, causing the frequency of control pulses to decrease to a value at which the value of the second 31stremote (minimum) current of the power gates (thyristors) exceeds

 -.

When the parameters of the load circuit change during the technological process, a resonant inverter can jump from the operation with the current form shown in FIG. A. To the current form shown in FIG. 4b. Such a transition is accompanied by a sharp decrease in output power from 100 to 10-15%, which makes it impossible to stabilize the output parameters of the inverter operating with the current form of power gates (thyristors) shown in FIG. 4a,

The proposed control method allows to prevent the specified transition and to provide the necessary accuracy of stabilizing the output power.

Claims (1)

Formula image shadows The control method of a resonant inverter, loaded on the oscillator five 0 The circuit, which controls the phase angle of the load, determines its limiting value, corresponding to the maximum value of the output power, and a hundred: it is eliminated at a predetermined level by adjusting the frequency of the control pulses, in that in order to improve the accuracy of stabilization of a given output power, they control the value of the second extremum (minimum) of the current of the inverter power valves, compare it with the specified minimum allowable value and if these the values produce a reduction in the frequency of the control pulses to a value at which the value of the second extremum (minimum) of the current of the power valves of the inverter is higher than the specified minimum value. 1 1 LK d FIG 2 fl , I., 4  / w,  KP Compiled by S.Stankevich Editor N.Tupitsa Tehred I.PopovichThe Corrector M.Sharoshi Order 5710/52 Circulation 659 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 Figm