Method for improving parallel connection stability of photovoltaic inverter and energy storage inverter

Abstract

The invention discloses a method for improving the parallel connection stability of a photovoltaic inverter and an energy storage inverter. The method specifically includes the following steps that: the output voltage uov, output current iov and inductive current iLv of the energy storage distributed power inverter are collected; the average active power Px and average reactive power Qx of a voltage controlled inverter are obtained by means of the calculation of an average power calculation method; the average active power Px and the average reactive power Qx are processed by a droop controller, so that an output voltage reference value uref can be obtained; the output current iov and parallel resonance suppression negative impedance zvir are multiplied, so that a virtual voltage uvir canbe obtained; the uref and the uvir are added up, so that a voltage regulator command voltage u'ref can be obtained; difference between the U'ref and the uov is obtained, so that iref can be obtained;difference between the iref and the iov is obtained, and the difference is processed by a regulator, so that modulation signals can be obtained; and modulation processing is performed on the modulation signals through a modulation module, so that the switching tube driving signals of the inverter can be obtained, the controller of the inverter controls the inverter according to the switching tubedriving signals. With the method of the invention adopted, resonance problems generated by the parallel connection of the inverters under different control modes can be solved.

Description

technical field [0001] The invention belongs to the technical field of distributed power generation under micro-grid island mode, and in particular relates to a method for improving the parallel stability of photovoltaic energy storage inverters. Background technique [0002] With the rapid development of national industrialization, people's demand for electricity is increasing day by day. The traditional power generation methods, such as coal, thermal power and other primary energy sources are non-renewable, and are one of the important factors in the formation of today's smog weather. A microgrid is a whole that combines distributed generation units, loads, power electronic converters, energy storage devices, and control units. These devices and loads make up this small power supply system, which operates in conjunction with the large power grid. Through the switch of the public connection point, it can control its grid-connected operation or island operation. When the m...

AI Technical Summary

Problems solved by technology

When these two distributed power sources are running in parallel, although each sub-unit can be stabilized independently, the interaction between the parallel units will cause the system to oscillate, resulting in system stability problems

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