Flexible Air Conditioning Loads as Voltage/Frequency-Responsive Sources in Microgrid

In renewables embedded microgrid system, the intermittent power sources and time-varying load demand can always induce voltage/frequency (v/f) stability issues. It is indispensable to retain sufficient power reserve so as to complement the instant generation-demand imbalance in real time. This paper investigates a novel air conditioning control framework, which is hooked up with a fully controllable PWM converter for re/active power regulation. Based on this new architecture, the air conditioning load (ACLs) is enabled to operate as a v/f responsive source beyond its original energy-consuming functionality. Toward this end, we propose an enhanced air conditioning (EAC) scheme based on model predictive control (MPC), through which the ACLs act as flexible loads to provide frequency reserve and reactive power compensation. Case studies on a small-scale microgrid are carried out, of which simulation results demonstrate the effectiveness of the proposed control scheme.