A battery energy storage power conversion system with Z-source network and its control method

Abstract

The invention relates to a battery energy-storage power conversion system containing a Z source network and a control method for the system. The power conversion system comprises a lithium battery system, the Z source network, a two-way DC / AC (direct current / alternating current) converter, a filter circuit and a DSP (digital signal processor) chip, wherein the lithium battery system, the Z source network, the two-way DC / AC converter and the filter circuit are connected with one another in sequence. The control method comprises the following steps: the DSP chip monitors the lithium battery system timely and controls the charging and the discharging for the DSP chip; the DSP chip monitors the Z source network; and the DSP chip monitors the two-way DC / AC converter. The scheme in the invention can overcome the defects of the existing power conversion system that the equipment is complicated, the two-way power conversion efficiency is low, the protection of an energy-storage battery system is absent, the allowable fluctuation range of the direct-current chain voltage is small, an inverter bridge arm switch tube can not be connected directly, the grid-connected harmonic filter effect is poor, etc.

Description

technical field [0001] The invention belongs to the technical field of electric equipment design, and in particular relates to a battery energy storage power conversion system including a Z-source network and a control method thereof. Background technique [0002] In 2011, my country's photovoltaic installed capacity was 3GW, while statistics from the National Energy Administration pointed out that the photovoltaic grid-connected installed capacity was only 2.14GW. This means that about 29% of the photovoltaic systems in the country have not yet been connected to the grid. The battery energy storage system can not only improve the grid-connected power generation capacity of intermittent energy sources, but also play an active role in the power generation, transmission, distribution and power consumption of the power system, and can complete the peak-shaving and valley-filling of the power grid and the impact of overload Regulation, frequency regulation and improvement of po...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the present invention provides a battery energy storage power conversion system with a Z-source network and its control method. The solution provided by the present invention overcomes the complex equipment, low bidirectional power conversion efficiency, and lack of Disadvantages such as energy storage battery system protection, small allowable fluctuation range of DC link voltage, switching tube of inverter bridge arm cannot be directly connected, and poor grid-connected harmonic filtering effect, etc.

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