Voltage and Frequency Controller with Power Quality Improvement for PMSG Based Pico-Hydro System

This paper proposes an improved-second order generalized integrator (SOGI) based decoupled voltage and frequency controller (DVFC) for permanent magnet synchronous generator (PMSG) based pico-hydro system with power quality improvement. The proposed pico-hydro system consists of a voltage source converter (VSC) used for harmonics mitigation, regulating voltage at point of common coupling (PCC), and DC-link voltage control. The decoupled frequency controller consists of a conventional electronic load controller (ELC) using uncontrolled three-phase diode bridge rectifier along with an insulated gate bi-polar transistor (IGBT) switch-based DC-DC converter connected in series to an auxiliary load. The frequency is regulated by dumping excess energy into the auxiliary load. The VSC and decoupled ELC, are connected in parallel to the load. The improved-second order generalized integrator (SOGI) based control algorithm is used to generate switching pulses for the VSC. The addition of damping factors, provides faster convergence, good dynamic response and improves steady-state performance of the given system. The proposed ISOGI based control algorithm with decoupled frequency controller for PMSG, is validated on a laboratory prototype with experimental implementation.