New reactive power control concept for converter based renewable energy sources

The paper presents a new approach to control of the reactive power supply from renewable energy sources to the grid. The aims of control algorithm are: maximal power extraction from the wind or solar power and its injection into the power grid and the control of reactive power supplied to the grid. The value of reactive power is controlled by magnitude of internal voltage E and phase angle δ between internal E and external V voltages vectors. The needed magnitude E and phase angle δ are calculated from the measured values of the supplied active power P_g and the desired supply of the reactive power Q_{g_ref}. These expressions are obtained by comparing mathematical models of the power converter and the synchronous generator. This concept was implemented on the abc stationary reference frame and its effectiveness was demonstrated on a simulation model of the power converter connected to an infinite bus.