An Adaptive Sliding Mode Controller for enhanced Q´-V droop in a microgrid

The state of the art power balancing control utilized in microgrids is known as `Power Frequency Droop´. Contemporary power frequency droop schemes utilise Proportional Integral (PI) controllers for voltage magnitude control. The power quantity directly coupled to the voltage is Q´ (Q-dash power). Q´ is present in, and affects, the error signal of the PI voltage controller. The controller is acting on two input signals, voltage and Q´. To avoid control interactions, the filtering applied to Q´ must be significantly slower than the filtering applied to the voltage. Thus the need to avoid control interactions leads to decreased bandwidth of the power control loop. This paper introduces an adaptive sliding mode voltage controller that is able to increase the power control loop bandwidth. The effectiveness of the control scheme is proven by results presented from SABER^® simulations and a dSPACE^® hardware system consisting of two inverters.