Six-phase synchronous vector modulation method of three-phase to six-phase matrix converter

Abstract

The invention discloses a six-phase synchronous vector modulation method of a three-phase to six-phase matrix converter. The method comprises the following steps: (1) six-phase output line voltage space vector modulation; (2) three-phase input phase current space vector modulation; (3) space vector modulation of a three-phase to six-phase matrix converter. According to the method, an indirect control strategy is adopted, a virtual intermediate direct current link is constructed, and the synthesis process of output voltage is decomposed into an alternating current-direct current conversion partand a direct current-alternating current conversion part; a space vector modulation method is adopted for the two parts, SVPWM rectification and inversion technologies are applied to synthesize inputcurrent waveforms and output voltage waveforms respectively, and the method is suitable for various six-phase inductive loads and particularly suitable for six-phase motor loads adopting vector control. By adopting the method, the control system is compact in structure, the size and the weight of the device are reduced, the control complexity of the system is effectively reduced, and the modulation workload is remarkably reduced.

Description

technical field [0001] The invention relates to the technical field of modulation algorithms of matrix converter-like AC-AC converters and control strategies of switching tubes therein, in particular to a six-phase synchronous vector modulation method for three-phase-six-phase matrix converters. Background technique [0002] Compared with conventional three-phase motors, multi-phase motors have insurmountable advantages in applications such as low-voltage, high-power, and high-reliability requirements. In these fields, multi-phase motors and their speed control systems have been widely used. Professionals and related practitioners generally pay attention and attach great importance to it. Multi-phase motor systems can use low-voltage power devices to achieve high-power control, avoiding the device voltage equalization problem caused by power devices connected in series; in the case of limited supply voltage, medium and high-power inverters can be controlled by a single power...

AI Technical Summary

Problems solved by technology

If the synchronization of rectification and inverter is out of tune, the current waveform on the input side will be seriously distorted, causing the power factor of the frequency conversion device to decrease significantly, and the harmonic content to increase significantly. At the same time, the voltage waveform on the output side also deviates far from the set waveform. bad

If there is a large degree of out-of-synchronization, it will seriously affect and interfere with the normal operation of the frequency conversion device, and even damage the device

In addition, compared with the matrix converter, there is an intermediate DC energy storage link. Since the capacitor is an inertial element, it takes a certain amount of time to charge and discharge. The larger the capacitance value, the longer the time required, which has a certain degree of adverse effects on the device. The start-up time of the main circuit is relatively prolonged, and the response speed is slowed down

The inverter part is a six-phase system. Although the modulation algorithm of the three-phase system is adopted, there are two sets of independent modulation and control units, and the scale and complexity of the device and system increase accordingly.

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