Способ уменьшения массы трансфильтров в многоканальном трехфазном инверторе напряжения с амплитудно-импульсной модуляцией

Abstract

The results from a structural-algorithmic synthesis of three-phase voltage source inverters (3PVSI) based on a three-phase bridge circuit with simple control algorithms are presented. An increased output power is achieved by applying the principle of multichannel energy flow conversion with summing its parts in the output circuit using transfilters (TF). The inverter output voltage has the waveform of a signal with pulse-amplitude modulation (PAM), which features better electromagnetic compatibility in comparison with pulse-width modulation. The output voltage waveform distortion tends to decrease with increasing the number of inverter channels. It is shown that the installed (overall with respect to the fundamental harmonic component) TF apparent power per phase - S*TF (in fractions of the one load phase output power) in its simplest two-channel version (at M=2) is 10%. With the number of channels increased to four, S*TF increases to 16%. To reduce the value of the indicator S*TF, it is proposed to use a new control algorithm of the two-channel inverter version, with which the TF operating frequency increases by 2n times (where n = 1, 2, 3, ... N) while maintaining the same output voltage waveform with PAM. Accordingly, the indicator S*TF decreases by 2n times. In this case, there is no voltage regulation function. To implement the output voltage regulation function for this inverter, an energy-saving control algorithm is used which is characterized by a minimum number of valve switching operations. It is shown that with shifting the TF to operate in the mode with a higher frequency, the indicator S*TF tends to degrade with increasing the control angle α. Based on a study of two alternative TF topologies in 3PVSI with M=4, it is shown that a more efficient solution in terms of S*TF is the version of a four-winding TF on a common (for one load phase) four-core spatial magnetic circuit. The obtained study results open the possibility to develop an extended information and methodological support necessary for system designing of electrical complexes using this class of three-phase voltage source inverters.