SU1246304A1 - Single-phase inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in electric drive and secondary power supply systems for converting a constant voltage to a single-phase sinusoidal variable. The purpose of the invention is to improve the mass and dimensional parameters and to expand the functionality by providing the ability to work on the load with any cos Ч. The inverter contains an output transformer 1, a main modulating switch (OMC) 3, a rectifying diode 7, a filtering capacitor 9, an inverting node 10 on the keys t1-1 i and a control unit 18 with a pulse generator modulated in a sinusoidal function and a pulse distributor current sensor 19. The introduction of an additional modulating key 8, return diodes shunting the keys 11-14, as well as the OMC 3 provides for regulation (stabilization) of the output voltage by changing the maximum fill factor of the clock pulses. Transform: - oro is made with a gap, has a minimum number of windings h and operates at a higher frequency, which allows reducing the weight and dimensions of the converter. 3 il. (/ GO 4 O 00 FIG.

Description

The invention relates to electrical engineering and can be used in electric drive and ali-electrical systems for converting a constant voltage to a single-phase sinusoidal variable by means of inverters.

The aim of the invention is to improve the mass-dimensional parameters and enhance the functionality by providing1. And the ability to work on loading with any cos..

FIG. 1 is a schematic diagram of an inverter; in fig. 2 shows the connection of the primary winding; FIG. 3 shows timing diagrams of the operation of circuit elements.

The inverter (Fig. 1) contains a jHoi; transformer 1, the primary winding 2 of which is connected to input inputs 4 and 5 through the main modulating switch 3.

The secondary winding 6 is connected via a rectifying diode 7, shunted by an additional modulating switch 8 5 to a filtering capacitor 9z in parallel with which the inverting node 10 is connected, which is connected to an inverted switch 11-14 connected in a bridge circuit. The output of the bridge is connected to the output pins 15 and 16, to which the load 17 is connected. Each of: to nights 3, 11–14 is controlled to conduct: m in one direction and uncontrolled in another direction, for example, in the form of a transistor with an oppositely connected diode. All are controlled from; using a control unit 18 containing a self-contained generator, a pulse width modulator and a pulse distributor.

To the input of the pulse distributor can be fed a signal taken from the output of the sensor 19 load current. The primary winding 2. of the transformer 1 for the purpose of locking the key 3 from the switching overvoltages created by the leakage inductance of the winding can be switched on, as shown in FIG. 2.,

For this, one more switch 20 is connected in series, and the ends of the winding 2 are connected to the input terminals by means of auxiliary diodes 21 and 22 the Inverter, operates as follows 3,

The clock pulses produced by the master generator of the block 18

Frequency modulated by i. i: o a law close to the output frequency.

These pulses and (fig, 3 / are supplied to the switch transistor, 3 only during the passage of the load current in the forward direction (,,) During passage: "the load current in the inverse direction (i ,,, ...") of the transistor

I. and g

key 3 is closed, and pulses are fed to the transistor of key 8, which add modulated pulses (Ug) that complement the clock frequency period. During the passage of current i (f, p

r with the open transistor of the key 3 in the transformer 1, energy is accumulated (its core is made with a gap and. from a magnet dielectric with low permeability), and with the closed transistor of the key 3 this. energy is transferred to the capacitor, 9 through the external lithium 7. When the current 1 is passed, the switch transistor is open ;; The energy from the fuse circuit nc fc of the capacitor 9) is transferred to the winding 6 of the transformer 1, and when the switch 8 is closed, this accumulated energy in the inductor of the transformer turns the power of the inverter through the diode 3 of the switch.

Thus, by means of the transformer 1 and the keys 3, and 7, 8, a uni-polar sinusoidal voltage is formed at the capacitor 9

5 bom direction of load current (U ;.). This voltage is converted by means of the keys 1,1-14 into a sinus AC, and long voltage. In one half period of the output frequency, the keys are open 11

0 tl 14, and in the other half period -, the keys 12 and 13. The moment of switching the keys 11-1.4 is synchronized with the modulating voltage of the output frequency of the block 18. In FIG. 3, the voltage is indicated and,

5 and the current z.ts on the load, the current 1 tlnm) transistor keys 11 and: 14, current .J ,, transistor keys 13 and 12, current 1, g. | 4 diodes keys 11 and 14, current i. ,,.,. ,, diode keys 13 and 12 and

JV A ;

5 V is the voltage across the winding 2 of the transformer 1.

. Non-switching of the pulse distributor of the block 18 from the mode of applying pulses to the transistor of the switch 3 on

the mode of applying pulses to the transistor 8 can be carried out 5 for example, at the command of the load circuit current sensor 19

0

31

at the moment of current transfer the load is zero.

In the embodiment of the inverter (Fig. 2), all the processes in the circuit occur as described. Keys 3 and 20 are switched simultaneously (synchronous and in phase).

The energy stored in the inductance of the dissipation of the primary winding 2, when locking the keys 3 and 20 of the transmission in the power source through the diodes 21 and 22, limiting the cai- "iM voltage on the keys 3 and 20.

The maximum fill factor of the switching pulses of keys 3 and 20 should not exceed 0.5. . The magnitude of the output voltage of the inverter is adjusted (stabilized) by changing the maximum fill factor of the clock pulses. The transformer has a minimum number of debris and operates at an increased (clock) frequency, and therefore its mass and dimensions are small. The dimensions of the keys 7, 8, 11-14 are also small, especially in the case when the output voltage of the inverter and when integrated hybrid-hybrid technology for semiconductor nodes is used.

The proposed inverter can operate normally without excluding the shape of the output voltage to load curve with any power factor i.e. in relation to the well-known, it has expanded functions and smaller mass and dimensions.

3044

Claims (1)

Formula and inventions A single-phase inverter containing an on-modulating key, connecting the primary winding of the output transformer to the input terminals of the inverter, filtering the capacitor, the first output of which is connected to the first output of the secondary winding of the output transformer, second terminal of which is connected to output from output -1I pins, control unit. and with a pulse generator,; sintered by the function of the output frequency of the inverter, the direct output of which is connected to the control input of the main modulating key, in order to improve the mass parameters and increase the functionality of ways to work on the load with any cos,, the second output of the filtering capacitor is connected to the junction point of the rectifier diode with the inverting unit, the inverting keys of which are shunted by the inserted return diodes, s bridge circuit and anti-parallel rectifier diode included additional modulating key, the control input of which is connected to an additional inverse output of the pulse generator, wherein BASIS - modulating the inputted key zashuntirovyn return diode. f Ut, mm 3.4 JT T + (/ Jiqil 2P y, z; i, 3 Compiled by T, Ershova Editor I. Bobkova Tehred V. Kadar Proofreader L. Pilipenko Order 4017/52 Circulation 631. Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-355, Raushsk nab, 4/5 Production and printing company, Uzhgorod, st. Project, 4 Fig.L