High-voltage direct-hanging energy storage method and system for eliminating charging and discharging frequency doubling current of battery

Abstract

The invention provides a high-voltage direct-hanging energy storage method and a high-voltage direct-hanging energy storage system for eliminating charging and discharging frequency multiplication current of a battery, and the method comprises the following steps: a single-star-type connected high-voltage direct-hanging energy storage power conversion step: injecting a set frequency-tripling common-mode voltage into bridge arm modulation voltage of a converter, the harmonic frequency in the direct-current bus current of the power module is increased to quadruplicated frequency from double frequency, and the set triple frequency common-mode voltage is directly superposed in the bridge arm modulation voltage; the single-angle-type connected high-voltage direct-hanging energy storage power conversion method comprises the following steps: injecting a set frequency-tripling common-mode current into a bridge arm of a converter, increasing the harmonic frequency in a direct-current bus current of a power module to quadruplicated frequency from double frequency, calculating a required frequency-tripling common-mode voltage according to the set frequency-tripling common-mode current, and carrying out single-angle-type connected high-voltage direct-hanging energy storage power conversion on the required frequency-tripling common-mode voltage, and the voltage is superposed to a bridge arm modulation voltage. According to the invention, the secondary harmonic current in the DC bus of the power module can be eliminated fundamentally, so that the demand of the system for a passive filter is reduced, and the power density of the system is improved.

Description

technical field [0001] The present invention relates to the technical field of electrical automation equipment, and in particular, to a high-voltage direct-mounted energy storage method and system for eliminating the frequency-doubling current of battery charging and discharging. Background technique [0002] In recent years, my country's new energy power generation represented by wind power and photovoltaics has continued to grow rapidly, resulting in profound changes in the power supply structure in the power system. As the proportion of renewable energy increases, problems such as consumption, transmission and distribution, and fluctuations in the power system have emerged. The rigid demand for energy storage has already taken shape, and it has become a key technology for the transformation of power production and consumption patterns and the transformation of energy structure in the future. [0003] In the high-voltage direct-mounted energy storage power conversion syste...

AI Technical Summary

Problems solved by technology

[0004] Connecting a passive filter in series between the H-bridge converter and the battery cluster is the easiest way to reduce the harmonic amplitude, but this will increase the size of the system, which is not conducive to the improvement of the power density of the converter

The method of adding a DC / DC bidirectional converter on the DC bus can achieve the effect of using a smaller filter to suppress the pulsating current, but this increases the cost and complexity of the system, which is not conducive to the improvement of reliability

Images