Large-capacity battery converter and control method thereof

Abstract

The invention discloses a large-capacity battery converter and control method thereof. The converter of the invention comprises several branch single stage type DC / AC converter modules parallel to one another. Each battery cluster (Battery Cluster BC) converges energy to an AC bus via each branch single stage type DC / AC converter module to be transformed in voltage in order to connect to an AC grid or to operate independently with load. The invention solves the circular current and uniform current problems brought by serial and parallel connection of the battery cluster, and adopts the technology of module combination and alternate balance to effectively improve the system efficiency under low power and power quality at the AC and DC sides and to realize balanced use of the battery cluster. Each battery branch can conduct intelligent charge and discharge management and the control function and the protection function are configured independently to ensure the largest availability of the system. The invention has simple structure, small volume, small energy loss, easy modularization, high reliability, small output harmonic wave, good system expansibility and low requirement to insulating ability of the converter and can operate with reduced capacity when the unit is in failure. The control method of the large-capacity battery converter of the invention is convenient and simple in operation and easy in realization.

Description

technical field [0001] The invention is a large-capacity battery converter and its control method, which belongs to the new technology of the large-capacity battery converter and its control method. Background technique [0002] With the wide application of various advanced technologies in power grids, intelligence has become an inevitable trend in the development of power grids, and the development of smart grids has reached a worldwide consensus. As a key link in the smart grid, energy storage technology can play a role in peak shaving and valley filling, peak shaving and frequency modulation, improving power quality, increasing system reserve capacity, delaying or even reducing grid expansion investment, smoothing intermittent problems of new energy, and improving distribution. power generation system or micro-grid stability. The battery energy storage system has the characteristics of being not affected by regional environmental factors and being flexible in layout. Wi...

AI Technical Summary

Problems solved by technology

The use of batteries in series can achieve the required DC input voltage, but the problem of unbalanced batteries is very easy to occur. At the same time, the design of the balance circuit and daily maintenance are also difficult; the use of batteries in parallel can double the capacity of the single battery, and at the same time bring more Circulation and current sharing problems

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