Control strategy for inverter in a micro-grid under unbalanced grid condition

Abstract

Micro-grid is gaining momentum as it addresses grave concerns like climate change and energy security. This paper presents power flow control algorithm for voltage source inverter used in a micro-grid under unbalanced grid conditions. Energy Storage and local energy source are the key components of the micro-grid that is required to help stabilize grid. There is a variety of technologies that can be used to store energy, but all these technologies have a controllable power electronic interface like inverters to mains (IEC 60038 Standard, Voltage: 400V, 50Hz, three-phase Supply). The control algorithm for inverter in this paper is based on dual vector current control. It gives robust operation of the inverter under generalized unbalanced input conditions. The control algorithm is based on the separate regulation of positive and negative sequence components, allowing the delivery of constant active power to the mains, and suppressing twice grid frequency oscillations. The presented control scheme improves voltage profile of the micro-grid. The control scheme is implemented in MATLAB/Simulink model and simulation results are presented. The results shows effectiveness of control scheme and are found in accordance with IEC standards and Engineering Recommendation P29.