H bridge cascaded multilevel inverter based on phase shift space vector modulation method

Abstract

The invention discloses an H bridge cascaded multilevel inverter based on a phase shift space vector modulation method. The H bridge cascaded multilevel inverter comprises an inverter body and a controller. The controller is used for sending a PWM pulse to a power switch in the inverter body. The inverter body comprises 3n H bridge units, and n is a series stage number of H bridges of each phase. In A, B and C phases, each phase has n H bridges in series connection, and the series connection refers to the series connection of output sides of the n H bridges. One end of H bridge AC ends connected in series is connected to an A, B or C end, and the other end is connected an N point. An input side of each H bridge is connected to DC power supply, and the power switch of the H bridge is driven by PWM pulse. The controller forms a PWM signal based on the phase shift space vector modulation method. The inverter is simple to drive and easy to implement.

Description

technical field [0001] The invention belongs to the field of inverter modulation, and relates to an H-bridge cascaded multilevel inverter based on a phase-shifting space vector modulation method. Background technique [0002] Due to the limitation of the voltage and capacity of power electronic devices, traditional two-level inverters usually adopt the "high-low-high" method to obtain high-voltage and high-power conversion through step-down and step-up of transformers, or use multiple small-capacity inverters The units are multiplexed through multi-winding transformers to realize high-voltage and high-power conversion. The system efficiency of these two high-voltage and high-power converters is relatively low. People hope to use direct high-voltage inverter technology to improve system efficiency. Therefore, the high-voltage and high-power two-level inverter technology based on direct series and parallel connection of power electronic devices has been studied. However, due t...

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Problems solved by technology

[0004] However, with the increase of the number n of cascaded units in the space vector modulation method, the number of basic vectors increases greatly, and corresponding to one basic vector, there are multiple redundant switch state vectors, and the selection of switch state vectors and the calculation of their action time are extremely complicated. The switch state vector switching path is diverse, which makes it difficult to realize the space vector modulation method

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