ALTERNATING CURRENT-DIRECT CURRENT HYBRID MICRO-GRID SYSTEM AND CONTROL METHOD THEREFOR

摘要

Disclosed are an alternating current-direct current hybrid micro-grid system and a control method therefor. The system comprises photovoltaic assemblies, inverters, a direct-current converter, storage batteries, a super-capacitor, an alternating-current load, a direct-current load, a direct-current bus, an alternating-current bus, an SVG, an APF, and the like. The control method comprises the steps of: first detecting the voltage and frequency of a main grid, and if normal, the system adopting grid-connected operation, or else, adopting isolated island operation; if the system is in grid-connected operation, the inverters all adopting PQ control and the direct-current converter adopting constant voltage control, and if the system is in isolated island operation, an energy storage inverter with the maximum capacity and the super-capacitor adopting V/F control, the remaining inverters adopting PQ control and the direct-current converter adopting constant voltage control; and finally under the premise of ensuring the normal operation of the system, ensuring that the energy storage capacity is within an optimal range.The present invention solves the operation control of a typical alternating current-direct current hybrid micro-grid system, improves the reliability, safety and economic efficiency of the system, and improves the utilization efficiency of renewable energy sources.