Energy storage system optimized carrier phase shifting method and system based on space vector embedding

Abstract

The invention provides an energy storage system optimized carrier phase shift method and system based on space vector embedding, and the method comprises the steps: obtaining a double switching frequency harmonic component of each inverter unit in a chain type energy storage system, wherein the double switching frequency harmonic component is represented in a vector form; then, determining an optimal phase shift angle combination of each inverter unit relative to a reference inverter unit when the vector sum of all double switching frequency harmonic components in the system is minimum based on a phasor diagram method; and finally, carrying out carrier modulation on the cascaded H-bridge chain type energy storage system by utilizing the optimal phase shift angle combination. According to the method, the space vectors of the subunits in the system are stacked and embedded one by one from the perspective of the graph theory to realize harmonic elimination, the optimized phase shift angle of the direct-current chain type energy storage system with any number of subunits is obtained by using the phasor diagram, and the method is simple; meanwhile, high-frequency harmonic waves of the chain type system can be effectively eliminated, and therefore high electric energy quality is achieved.

Description

technical field [0001] The invention belongs to the technical field of smart grid energy storage systems, and in particular relates to a method and system for optimizing carrier phase shifting of energy storage systems based on space vector embedding. Background technique [0002] Each phase of a chain-structured battery energy storage system (BESS) is formed by cascading multiple H-bridge (HB) energy storage units. This circuit topology can use power switching devices with lower withstand voltage to achieve energy conversion at higher voltage levels, without the need for step-up transformers. Good scalability. Therefore, this topology is widely used in various high-voltage and large-capacity occasions. [0003] At present, the commonly used modulation strategy of cascaded H-bridge chain energy storage system is the carrier phase-shift modulation strategy. power and ease of implementation of modular distributed control. However, when the state of charge of each energy st...

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Problems solved by technology

[0004] In view of this, the present invention aims to solve the problem that when the state of charge of each energy storage battery module is difficult to ensure complete consistency, resulting in power imbalance between modules, the frequency doubling effect of traditional carrier phase-shift modulation will fail, and the high-frequency harmonics of the output voltage will The problem that the weight cannot be eliminated

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