A novel modular voltage and frequency controller for standalone wind energy conversion system

Standalone generation schemes based on local renewable energy sources have great potential to replace diesel-generators supplying remote communities. However, consumer loads and renewable energy sources are variable in nature and require power management to maintain supply quality. This paper presents scheme for voltage-frequency regulation in standalone wind generation under variations in un/balanced load power and wind velocity. A modular Generalized Impedance Controller (GIC), having multiple number of flexible low rating units of single-phase PWM-VSCs with amply rated dc bus batteries is proposed to attain the control objective. The GIC exchanges active-reactive power independently in each phase to maintain balanced and regulated voltage and frequency under varying source and un/balanced load powers. Individual VSC-battery units are attached/detached to/from any phase based on battery SOC and power exchange requirement in that phase. Such modular GIC structure offers cost effective solution with better reliability and redundancy even under severe unbalanced loading due to per phase power handling with optimal storage units. Performance is simulated under various operational conditions to show efficacy of scheme.