Research on Power Control Strategy for Micro-Grid Based on Inverse System

Abstract

In this paper, the characteristics of the power control and control method in micro-power is studied in detail. There is a big difference between line parameters of micro-grid and high voltage grid, active power and reactive power in micro-power are coupled together, so active power and reactive power control is different from high-voltage transmission system. Control strategy of Q-U and P-f is no longer suitable for micro-grid. To realize active power control and reactive power control, the decoupling of active power and reactive power must be achieved. Nonlinear system can be linearized and decoupled to achieve by inverse system as show below: power transmission decision unit firstly calculate active power and reactive power in the transmission line, then decoupling control unit of inverse system respectively calculate RMS voltage and phase angle according to input variables (active power and reactive power), finally Pulse Width Modulation (PWM) control unit simultaneously calculate and send out the pulse signal to adjust the inverter of distributed generation and realize power control in transmission lines. This method is easy and simple. The simulation results show that the decoupling effect is obvious.