Power Management Strategy of AC-DC Hybrid Microgrid in Island Mode

In order to solve the problem of power energy coordinated management , control and quality in the AC-DC interconnected Microgrid system, this paper proposes an AC-DC $\omega - V_{dc}^2$ droop control strategy applied to the energy router, and the approach is derived from conventional ω-P droop control scheme in AC Microgrid and the Vdc − P droop control scheme in the DC micro-grid . Combined with the square value of DC voltage and AC frequency characteristics to control the flow direction and magnitude of power, and it realize the bidirectional stable energy transmission of AC-DC Hybrid Microgrid, and ensure the energy balance of the Microgrid networks.

1 Introduction

In recent years, due to the environmental problems of traditional power generation and the exhaustion of non-renewable energy, the development of renewable energy source, including wind power generation, photovoltaic power generation, fuel cells and small gas turbines have been proposed. Although these new types of clean energy are often subject to natural conditions and have a certain randomness, there is no doubt that renewable energy source will become an important part of the power grid in the future. Base on this background, the Microgrid (MG) is becoming hot topics in the global power electrical system, so the renewable energy source, combined heat and load is element of MG. Normally, it has DC-MG, AC-MG and AC-DC hybrid MG. DC-MG, mainly composed of photovoltaic power generation and DC load. AC-MG, mainly composed of fans, tides, hydropower stations, etc. For the AC-DC hybrid MG, including DC MG and AC MG, need to have a good energy transfer between each other, and jointly ensure the load in MG and the stability of grid connection ^[1].