Voltage and frequency regulation of standalone self-excited induction generator for micro-hydro power generation using discrete-time adaptive control

This study deals with the development of a control system for voltage and frequency regulation of a micro hydro power generation system, fed by self-excited induction generator (IG). The generation system considers a four-wire three-phase grid, composed by three phases plus neutral conductor, fed by three-phase three-wires IG. The neutral conductor is created from the neutral point of star connection of excitation capacitors bank. The four-wire configuration allows the connection of three-phase loads in star or delta configuration, as well as single-phase loads. The voltage regulation is performed through a four-legs distribution static synchronous compensator (DSTATCOM) shunt connected to the AC bus. It is considered the employment of adaptive control techniques and the compensation of load current unbalances, which offers suitable voltage regulation in conditions of system's parameters variations such as load connection and disconnection, and changes in IG's unmodelled parameters, and voltage unbalance compensation, respectively. Frequency regulation is obtained by electronic load control connected to the DC bus of DSTATCOM. Experimental results were obtained to demonstrate the good performance of the voltage and frequency regulation control system during loads transient, including three-phase and single-phase loads.