SU1374378A2 - Inverter control device - Google Patents

Abstract

This invention relates to the field of electrical engineering and can be used in power converters of direct current (voltage) to alternating current. The purpose of the invention is to increase the inverter CCC and reduce the amplitude of the high-frequency current ripple in the load. The parts of the positive half-wave voltage, formed by the digital-analog converter 4, are fed to one input of the blocks 8, 9, 10 of the formation of the width-modulated voltage for the negative half-wave voltage, to the other inputs of which a sawtooth voltage is applied. Depending on the connection of the inputs of blocks 8, 9, 10, one of the input signals is inverted and then compared with the other, with the result that at the output of blocks 8, 9, 10, the width-modulated voltages Ug are generated, and, o, the presence of which allows It is not necessary to form a voltage at the output of the inverter without changing the harmonic composition according to the optimal laws of switching of the inverter power switches, which prevent polarity changes on the load at the inter-switching interval. 1 h, para. f-ly, 3 ill. (L

Description

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The invention relates to electrical engineering and can be used in power converters of direct current (voltage) to alternating current.

The purpose of the invention is to increase the efficiency of the inverter and reduce the amplitude of the high-frequency current ripple in the load.

FIG. 1 shows a functional diagram of an apparatus for controlling an inverter; in fig. 2 and 3 are possible embodiments of blocks of the formation of width-modulated voltages for a negative half-wave voltage.

The device (Fig. 1) contains a reversible counter 1, to the input of which high-frequency signals are received, the counter 1 contains a block 2 in which all the low-order bits are located, sequentially connected to the high-discharge block 3, which is made according to a ring multiphase circuit with the number of phases equal to the number of the inverter, the digital buses of the block 2 are connected to the inputs of the digital-to-analog converter 4, the outputs of which are connected to one of the inputs of the adders 5-7 and blocks 8-10 of the formation of width-modulated voltages at negative half-waves the number of outputs of the digital-analog converter is determined by the number of sections into which the half-wave voltage is broken, the other inputs of the adders 5-7 and blocks 8-10 are connected to the source 11 of the saw-tooth voltage, and the outputs to the inputs of the distributor 12 pulses, the control inputs which are connected to the outputs of block 3 of the highest bit, and the outputs are the outputs of the device. Each block of the formation of width-modulated voltages at a negative voltage half-wave contains a series-connected inverting amplifier 13 with a unit gain and an adder 14, with the input of the inverting amplifier and the second input of the adder being block inputs. figurative voltage and digital-analog converter, respectively, or vice versa, and the output of the adder is the output of the specified block (Fig. 2 and 3).

The device for controlling the inverter operates as follows.

Pulses with a frequency f are fed to the input of the reversible counter 1, where they are added (subtracted). When the lower bits are filled and the low bits counter is reset to zero (maximum) position in the high bit 3, the unit is summed (subtracted). The highest bit of the counter is executed on six digits 0-5. The low-order digits form three voltage sections in the digital-analogue converter 4 for a positive half-wave, and for a segment O - 60 degrees, U4 - for a segment 60–120 degrees, and | - for a segment of 120 - 180 degrees. Comparison of these voltages with a sawtooth reference voltage in adders 5-7 gives three width-modulated voltages Uf, and, UY for one polarity.

Depending on the connection of the inputs of blocks 8-10, they invert one of the input signals and compare it with the other in the adder 14. As a result, pulse-modulated voltages 8 and for the other polarity are formed at the output of these blocks. Latitude-modulated voltages f Ug, UY, Ug, and,, UIQ are fed to the inputs of the distributor 12 pulses. The key elements of the distributor 12 pulses switch from the higher-order digits of the reversible counter and send pulse-modulated voltages and., Ug, and, CB, and,, and, to the output buses in accordance with the required law.

The formation of the width-modulated stresses Uj-, Ug, 1) 7 in the prototype and the proposed device is the same.

The presence of voltages Ug, Ug, and Tsz allows forming a width-modulated voltage at the output of the inverter without changing the harmonic state according to the optimal commutation laws of the inverter power switches, preventing polarity change at the load at the inter-switching interval, which can increase Efficiency of the inverter and decrease the amplitude of the high-frequency ripple current in the load.

Claims (2)

1. Device to control the inverter auth.St. No. 653723, in order to increase the efficiency of the inverter and reduce the amplitude of high-frequency current ripples in the load, blocks for the formation of width-modulated voltages are introduced at a negative voltage half-wave, the number of which is equal to the number of outputs of the digital-analog converter, and the inputs of each of the These blocks are connected to the outputs of a digital-to-analog converter and a sawtooth source, and the outputs to the inputs of a pulse distributor. It / nu Go P , J FIG. 2 2. The device according to claim 1, wherein the each unit for generating pulse-width modulated voltages at a negative voltage half-wave comprises an inverting amplifier with a unit gain and a comparator unit connected in series, and the input of the inverting amplifier and the second input Comparison unit are the inputs of the unit for the formation of the width-modulated voltage at a negative voltage half-wave, and the output of the comparison unit is its output. 3