Improved V/f control strategy for microgrids based on master–slave control mode

Abstract

The V/f control adopted by the master power supply has problems of slow dynamic response, poor anti-interference ability in response to micro-source output power fluctuations and loads abrupt change. Aiming at problems of the output voltage mentioned above, an improved V/f control strategy based on compound control is proposed in this study. The improved V/f control strategy is composed of two parts, feedforward compensation and robust feedback control. The design of the feedforward compensator is realised by the method of approximate full compensation. The design of the robust feedback controller is transformed into solving a convex optimisation problem with linear matrix inequality constraints and linear objective functions. The designed V/f control strategy is verified by a variety of comparative tests. Test comparisons show that the controller can get better voltage output characteristics, dynamic characteristics and robustness in response to micro-source output power fluctuations, loads abrupt change or non-linear loads and unbalanced loads.