RU98650U1 - AUTONOMOUS VOLTAGE INVERTER - Google Patents

Abstract

 A self-contained voltage inverter containing a rectifier, a bridge converter made on diodes and semiconductor switches, for example transistor, active-inductive load and a control system consisting of two identical key control channels, each of which contains control pulse shapers, the outputs of which are connected to the corresponding inputs keys, characterized in that the introduced clock generator with two antiphase outputs, each of which is connected to the trigger inputs of the form of the corresponding channel, the regulator whose output is connected to the additionally introduced regulatory input of the second shaper of each channel, while the pause between the trailing edge of the pulse of shorter duration τ2 of the second shaper of one channel and the leading edge of the pulse of longer duration τ1 of the first shaper of the other channel is longer than the decay time of the load current to zero.

Description

The utility model relates to electrical engineering, in particular, to the field of converter technology for low frequency converters.

Known autonomous voltage inverter (hereinafter AIN), made on the basis of two-operational lockable thyristor keys with pulse-width regulation and a DC link, made on a rectifier with a capacitor filter (Rudenko BC, Senko V.I., Chizhenko I.M. technology ”. / M .: Higher School, 1980, p.237-240). The conversion of direct voltage to alternating current for supplying an active-inductive load of a given frequency occurs by switching diagonally arranged key pairs with pulses offset by 180 ° el. When switching the keys, the electromagnetic energy of the load is discharged into the capacitor bank of the DC voltage source. At a current of several hundred amperes and low frequencies, the capacitance of a capacitor bank can reach farads.

The closest in technical essence to the claimed technical solution, taken as a prototype, is an AIN made on single-operation thyristor keys, with an active-inductive load and a two-channel control system SU (Rozanov Yu.K. "Fundamentals of power electronics". / M .: Energoatomizdat, 1992, p. 235-237). The operation of the device is based on pulse-width regulation of switches VS ₁ -VS ₄ , which are shunted by the reverse diodes VD ₁ -VD ₄ and are connected at the AIN input to a constant voltage source U _d , which when powered by an AC network consists of a rectifier with a parallel capacitor. The pairs of thyristors VS ₁ , VS ₄ and VS ₃ , VS ₂ , are switched by antiphase pulses with a frequency / using auxiliary switching thyristors VS ₁ '-VS ₄ ' and reactive elements C _k , L _k , which can be eliminated, for example, when using fully controlled thyristors and transistors.

The device also contains the driving generators ЗГ ₁ , ЗГ ₂ , control phase-shifting devices ФУ, ФУ ₁ -ФУ ₄ , switchgear devices ПРУ ₁ , ПРУ ₂ , output pulse shapers for thyristor switches FI ₁ -FI ₄ and FI ₁ '-FI ₄ '.

The disadvantages of the prototype are:

- the need for a capacitor bank with large capacitances to discharge the reactive energy of the load when performing a constant voltage source U _d in the form of a rectifier and large overall dimensions;

- the complexity of the control system.

The technical result of the claimed utility model is to simplify the AIN circuit and control system, increase the reliability of the device.

The technical result is achieved by the fact that in a stand-alone voltage inverter containing a rectifier, a bridge converter made on diodes and semiconductor switches, for example, transistor, active-inductive load and a control system consisting of two identical key management channels, each of which contains control drivers pulses, the outputs of which are connected to the corresponding inputs of the keys, introduced a clock generator with two antiphase outputs, each of which is connected to to the triggering inputs of the shapers of the corresponding channel, the regulator, the output of which is connected to the additionally introduced control input of the second shaper of each channel, while the pause between the trailing edge of the pulse of shorter duration τ _{2 of the} second shaper of one channel and the leading edge of the pulse of longer duration τ _{1 of the} first shaper of the other channel is longer the time the load current drops to zero.

The essence of the utility model is that due to the implementation of the second drivers of control pulses of each key control channel with two inputs - a trigger and a control, the introduction of a clock pulse generator with two antiphase outputs, each of which is connected to the trigger inputs of the first and second formers of the corresponding channel with output pulses of various durations, as well as the introduction of a regulatory body, the output of which is connected to the regulatory input of the second shaper of each channel la is achieved the possibility of regulating the output voltage AIN while simplifying circuit and increasing the reliability of the whole device.

Figure 1 shows a diagram of the inventive single-phase bridge ANN, where the following notation:

1 - rectifier;

U _d is the average value of the output voltage of the rectifier 1;

2 - bridge converter;

3, 4, 7, 8 - diodes;

5, 6, 9, 10 - transistor switches;

11 - active inductive load;

u, i - respectively, the voltage and current at the load 11;

12 - control system;

13 - a clock generator with two out-of-phase pulses outputs with a frequency f;

14, 15 - two identical key management channels 5, 10 and 9, 6;

16 - the first driver of control pulses FI1 duration τ ₁ ;

17 - the second driver of the control pulses FI2 duration τ ₂ ;

18 - regulatory authority.

Figure 2 shows a diagram of the inventive device, where:

- chart a) - antiphase clock pulses TI1 and TI2 in the control channels 14, 15 at the outputs of the generator 13 with a frequency f of figure 1, 2;

- diagram b) - diagram of the AIN:

u (t) is the voltage at the load;

I _m is the amplitude value of the load current;

- diagram c) - current-conducting elements of the AIN;

- diagram d) - diagrams of control pulses with durations τ ₁ and τ ₂ received from the shapers of control pulses 16, 17 of the control channel 14 and received on the corresponding keys 5, 10;

Δt is the delay ("dead" time lasting several microseconds), excluding the simultaneous operation of two keys (5, 6 and 9, 10) when they are switched and shorting rectifier 1 (Fig. 1, 2).

- chart e) - diagrams of control pulses with durations of τ ₁ and τ ₂ received from the pulse shapers 16, 17 of the key control channel 15 and received on the corresponding keys 9, 6.

AIN contains a rectifier 1, a bridge converter 2, consisting of diodes 3, 4 connected in parallel to the corresponding transistor switches 5, 6 and diodes 7, 8 connected to the transistor switches 9, 10, between the indicated pairs of transistor switches the active-inductive load circuit 11 is connected These transistor keys are controlled by a control system 12 comprising an antiphase clock pulses generator 13 with a frequency f and two identical control channels with keys 14, 15, each of which has pulse shapers Owls: 16 - the first driver of control pulses FI1 of duration τ ₁ with a trigger input, 17 - the second driver of control pulses of FI2 duration τ ₂ with a trigger and control inputs. The triggering inputs of the control pulse shapers 16, 17 are interconnected and connected respectively to the first and second outputs of the clock pulse generator 13. The regulatory body 18 is connected to the control input of the control pulse shaper 17 in each control channel and provides control of the duration τ _{2 of the} control pulse. The outputs of the control pulse shapers 16, 17 in both control channels 14, 15 are connected to the control circuits of the corresponding transistor switches 5, 10, 9, 6. Between the trailing edge of the pulse with a shorter duration τ _{2 of} one channel and the leading edge of the pulse with a longer duration τ _{1 of the} other channel creates a pause Δτ ₀ (figure 3), which is more than time t _{1 the} recession of the load current to zero.

The work of the AIN is as follows.

Management of transistor switches 5, 6, 9, 10 is carried out by pulses of different durations (figure 3). Transistor switches 5 and 9 are controlled by pulses , and transistor switches 6 and 10 - by pulses of shorter duration τ ₂ generated by control channels 14, 15. As a result, at the end of pulses with a duration τ _2, transistor switches 10 and 6 are closed and the load current is closed through diode 7 and transistor switch 5, respectively a half-period of frequency f and through a diode 3 and a transistor switch 9 in the second half-cycle. In this case, there is a pause Δτ ₀ in the voltage diagram at the load u (t), which is determined by the current decay time to zero t ₁ and the delay time Δt. The inclusion of the next pair of transistor switches occurs after a delay Δt (several microseconds), which excludes the simultaneous switching on of the state of the transistor switches 5, 6 or 9, 10, which could lead to shorting of the rectifier 1. The total pause in the load voltage diagram is:

Δt ₀ = t ₁ + Δt,

Where:

t ₁ ≈ 4T _n with the exponential nature of the rise and fall of the current;

T _n - time constant of the active-inductive load 11 (figure 1).

The voltage regulation on the active inductive load is carried out by changing τ ₂ depending on the regulation signal U _p at the input of the regulatory body.

The effective value of the output voltage of the AIN is determined by:

,

Where:

τ _2р is the pulse duration of FI2 in radians;

τ _2s is the pulse duration of FI2 in seconds;

f is the frequency in hertz.

The inventive device has several advantages compared with the prototype. By simplifying the control system and eliminating the capacitor at the output of the AIN rectifier when it is powered from the AC mains, the circuit is simplified and the reliability of the device is increased, and the introduction of a regulatory body allows you to adjust the output voltage of the AIN.

Claims (1)

A self-contained voltage inverter containing a rectifier, a bridge converter made on diodes and semiconductor switches, for example transistor, active-inductive load and a control system consisting of two identical key control channels, each of which contains control pulse shapers, the outputs of which are connected to the corresponding inputs keys, characterized in that the introduced clock generator with two antiphase outputs, each of which is connected to the trigger inputs of the form irovateley corresponding channel, the regulator, the output of which is connected to the further introduction of regulatory input of the second driver of each channel, wherein the pause between the trailing edge of a pulse of shorter duration τ ₂ of the second shaper of one channel and the leading edge of a pulse of longer duration τ ₁ of the first shaper other channel longer decay time load current to zero.