Design and Control of Autonomous Wind–Solar System With DFIG Feeding 3-Phase 4-Wire Loads

Abstract

This paper presents the design, control, and experimental investigation of an autonomous wind–solar hybrid energy system feeding 3-phase 4-wire loads. The wind energy block consisting of a double fed induction generator (DFIG) is equipped with maximum power point tracking (MPPT) algorithm. The control of DFIG consists of two converters, namely rotor side converter (RSC) and load side converter (LSC) connected back to back at dc link. The MPPT operation requires speed control, which is realized using field oriented control through RSC. The rotor position required for vector control is estimated with model reference and adaptive system algorithm. The voltage and frequency control is realized through LSC. The solar photovoltaic (PV) power is extracted using a dc–dc boost converter to the common dc link. The dc–dc converter is also equipped with MPPT algorithm to extract maximum power from the incident irradiance. The system is modeled in MATLAB and its performance is presented at conditions, e.g., unbalanced nonlinear load, varying wind speeds, and solar irradiation. Under all these conditions, currents flowing through stator windings of DFIG are balanced with low total harmonics distortion (THD). The THDs of load voltages under all operating conditions are also within requirement of IEEE 519 standard. Finally, simulated results are validated experimentally by developing a prototype of the system using a 5-kW solar array simulator and a 3.7-kW DFIG.