Control method and control apparatus of energy storage inverter parallel system

Abstract

The invention discloses a control method of an energy storage inverter parallel system. The method comprises the following steps: respectively detecting DC voltages of M energy storage inverters; determining a work state of the energy storage inverter parallel system; according to the work state, determining that energy storage inverters according with starting conditions among the M energy storage inverters are started, if the work state of the system is a discharge state, ordering the DC voltages of the energy storage inverters according to a decreasing sequence, when a difference U1<*> between the DC voltages of the top two is greater than a voltage threshold U0, determining that an energy storage inverters corresponding to highest DC voltages are energy storage inverters to be started, if the work state of the system is a charge state, ordering the DC voltages of the energy storage inverters according to an increasing sequence, when a difference U2<*> between the DC voltages of the top two is greater than the voltage threshold U0, determining that energy storage inverters corresponding to lowest DC voltages are energy storage inverters to be started; and according to a first preset rule, controlling operation of the energy storage inverters to be started. Based on the control method disclosed by the invention, the stability of the system can be improved.

Description

technical field [0001] The invention belongs to the technical field of energy storage inverters, and in particular relates to a control method and a control device for a parallel system of energy storage inverters. Background technique [0002] With the continuous expansion of the capacity of new energy power stations, in order to realize the optimal allocation of energy storage inverter capacity, the parallel connection of energy storage inverters has become a trend of technological development. [0003] figure 1 It shows a structure of the energy storage inverter parallel system, the energy storage inverter parallel system includes the energy storage inverter 1 to the energy storage inverter M, M is an integer greater than 1, and each energy storage inverter The DC side of the inverter is connected to a battery, and the AC sides of multiple energy storage inverters are connected in parallel. Of course, LC filters, DC EMI filters, AC EMI filters and other devices can also...

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Problems solved by technology

[0004] However, the DC sides of multiple energy storage inverters are connected to different batteries. When the voltages of the batteries are inconsistent, multiple energy storage inverters form a common-mode loop through parasitic capacitance coupling, and the common-mode voltage in the common-mode loop will be A common-mode circulating current is generated between the energy storage inverters, which affects the stability of the energy storage inverter parallel system

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