Design and implementation of dynamic electronic load controller for three-phase self-excited induction generator in remote small-hydro power generation

Abstract

This study presents design and implementation of a dynamic electronic load controller (DELC) for voltage and frequency control of a three-phase self-excited induction generator (SEIG) driven by constant power unregulated small-hydro turbine. This DELC is a combination of insulated-gate bipolar transistor-based voltage sourced converter (VSC) and variable frequency drive (VFD) which is connected across the DC link of VSC. The VFD operates in direct torque control mode and is coupled with a pumping system. The DELC is connected at point of common coupling in parallel with consumer loads. The VSC provides instantaneous control of the SEIG voltage through reactive power compensation. The VFD consumes the power in excess of consumer loads to maintain constant generator output power which in turn regulates the frequency. The excess generated power consumed by the VFD is used to pump water either to an overhead tank or for irrigation purposes. The performance of the proposed DELC of SEIG is demonstrated under various types of loads such as linear/non-linear, balanced/unbalanced loads and so on. Test results recorded on a developed DELC of SEIG exhibit simultaneous voltage and frequency control capabilities of the DELC under varying loads.