Experimental analysis of a modified scheme for supplying single-phase remote loads from micro-hydro based three-phase self-excited induction generator

Abstract

Induction machine (IM) plays significant role in rural electrification, acting as a generator for small kilowatt to large megawatt applications. These IMs are therefore used for power generation, gaining a huge acceptance within the researchers because of its brushless system, robust design and cheap market rate. In off-grid operation, the induction generator (IG) also known as self-excited IG (SEIG), requires supply of external reactive power (RP) for building up its terminal voltage and satisfying the electrical load demand. A small kilowatt level renewable-driven three-phase SEIG is generally deployed for generating single-phase power in off-grid mode for remote areas. Generation of single-phase power and supplying the load from a three-phase SEIG in off-grid operation, results in the imbalance of the SEIG's stator current and phase voltage. In this regard, various capacitor-based excitation (CBE) schemes have been reported for supplying the required RP to the three-phase SEIG and generating single-phase power, while reducing the mentioned difficulties. The current paper emphasizes on the steady-state mathematical formulation of a proposed modified CBE scheme for generating single-phase power and supplying remote hilly load from a hydro-driven three-phase SEIG under the fixed speed of the generator. Further, a state-of-the-art experimental test-bench of the proposed scheme, where a hydro-driven three-phase SEIG supplying single-phase resistive-inductive (RL) load has been showcased with the same being simulated in the MATLAB environment. The result indicates that the proposed CBE scheme can effectively supply single-phase RL load of different power factors (p.f.), having promising voltage regulation with balanced SEIG operation.