Adaptive harmonic cancellation scheme for voltage and frequency control of a single-phase two-winding SEIG

This paper presents the adaptive harmonic cancellation (AHC) scheme for Decoupled Voltage and Frequency Controller (DVFC) for a single-phase two-winding self excited induction generator (SEIG) based small uncontrolled hydro turbine driven off-grid generating system. This DVFC consists of a Voltage Source Converter (VSC) and a controlled auxiliary load. In this proposed scheme, the voltage and frequency of the system are controlled independently of each other. The AHC scheme inherently produces a pure filtered sinusoidal signal of the system voltage which is used as an input to the Frequency Estimation Block (FEB) to estimate the system frequency. The information about time period of the every cycle is used to create a 90° phase shift in the next cycle of SEIG output voltage in frequency adaptive quadrature unit template generation block. This quadrature signal is used to estimate the reactive power compensation requirement of the system. The proposed control algorithm of DVFC of SEIG is implemented using a Digital Signal Processor (DSP).