Switched capacitor N-level inverter and modulation method thereof

Abstract

The invention provides a switched capacitor N-level inverter and a modulation method thereof. The inverter comprises a single DC input power supply, a switched capacitor unit and a full bridge unit. The switched capacitor unit is connected in parallel with the single DC input power supply and used for performing series-parallel conversion between the single DC input power supply and the capacitorsof the switched capacitor unit and outputting a multi-step voltage. The full bridge unit is connected in parallel with the switched capacitor unit, and is used for outputting the multi-step voltage output by the switched capacitor unit after positive-negative polarity conversion. The modulation strategy adopted is a step wave specific harmonic elimination modulation mode based on the combinationof specific harmonic elimination and step wave modulation. The inverter of the invention can output any level by expanding the modular structure of the switched capacitor sub-modules, and the number of power devices of the inverter is greatly reduced through a simpler modular structure.

Description

technical field [0001] The invention relates to the fields of electric energy conversion and new energy distributed grid-connected power generation, and specifically relates to a switched capacitor N-level inverter and a modulation method thereof. Background technique [0002] Energy is an important resource for human survival. However, with the continuous exploitation and utilization of human beings, the traditional fossil energy is facing depletion due to its limited reserves, and the energy crisis is unfolding on a global scale, and people's wanton exploitation and utilization of fossil energy has also brought serious environmental pollution problems. Therefore, the development and utilization of abundant, clean and pollution-free renewable energy has attracted worldwide attention. [0003] In the renewable energy generation system, the power electronic inverter is the key link of its electric energy conversion and transmission, and the power electronic inverter has an i...

AI Technical Summary

Problems solved by technology

However, the topology of the existing switched capacitor multilevel inverter is fixed, the transformation is single, the structure cannot be expanded, and the number of output levels is small; some existing scalable switched capacitor multilevel inverters require a large number of devices , the voltage stress of the device is large, which limits its application range, so it is of great significance to find a new type of inverter with flexible expansion, a small number of devices, and low voltage stress

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