Equivalent space vector carrier modulation multilevel converter control method

Abstract

The invention discloses an equivalent space vector carrier modulation multilevel converter control method, belonging to the technical field of control and adjustment of converters. The method comprises the following steps of: for a k level converter space vector equivalent carrier mode, adopting k-1 heavy no-phase shift carriers for modulation, wherein the interval of the heavy carriers and the per-unit value are as shown in the specification, and a unified form of a zero-sequence component as shown in the specification is acquired; for a three-phase reference modulation wave, comparing the values according to an effective output time to obtain the maximum value, intermediate value and minimum value of the three-phase reference voltage; calculating the direct current offset in the zero-sequence component according to the three-phase reference modulation wave, adding the three-phase reference modulation wave to the zero-sequence component to obtain an equivalent space vector reference modulation wave; modulating by selecting the corresponding carrier according to the reference voltage, and outputting a waveform equivalent to the space vector carrier modulation. The invention has the beneficial effects of quickly and accurately solving the zero-sequence component, simultaneously, greatly simplifying the calculated amount, and being easy to realize in real time.

Description

Technical field [0001] The invention relates to a control method of an equivalent space vector carrier modulation multilevel converter, which belongs to the technical field of converter control and adjustment. Background technique [0002] The space vector SVPWM modulation technology starts from the inverter-motor as a whole, and aims at constructing the flux linkage circle for PWM control. The physical concept is clear and clear, and good control effects can be obtained. At the same time, it can control switching loss, output harmonic content, and DC voltage. Optimize and improve the utilization rate and other aspects. However, SVPWM technology requires a series of work such as sector judgment, vector selection, and action time calculation. As the number of levels increases, the complexity of the SVPWM algorithm increases sharply, and it is not suitable for real-time calculation. At present, the SVPWM technology is only successful. Used in three-level and below converters. [00...

AI Technical Summary

Problems solved by technology

However, SVPWM technology needs to perform a series of tasks such as sector judgment, vector selection, and action time calculation. With the increase of the number of levels, the complexity of the SVPWM algorithm increases sharply, which is not suitable for real-time calculation. At present, SVPWM technology is only successful Applied to three-level and below converters

[0003] Carrier modulation outputs waveforms by comparing the three-phase reference waveforms with triangular carrier waves. The calculation is simple and easy to implement. However, the low utilization rate of DC voltage is its main defect. In addition, different carrier modulation methods will also bring differences to the quality of output waveforms. Impact

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