Improvement of DPC of Grid-Connected Inverter for Wind Power System

Abstract

This paper analyzes the principle and properties of the traditional direct power control (DPC) system for the three-phase grid-connected voltage source inverter based on its mathematical model. Hysteresis comparators in power loop of DPC control system, leading to the switching frequency not fixed .the fluctuation of power and DC voltage in temporary state. This paper brought an improved program. The active and reactive powers are calculate by estimating the virtual flux. The AC side voltage sensors could be replaced. The SVPWM has been utilized instead of the power hysteresis and switching table of the traditional DPC system.