Analysis and Design of Electronic Load Controller for Self-Excited Induction Generators

This paper presents an analysis and design of an electronic load controller (ELC) for three-phase self-excited induction generators (SEIGs) suitable for stand-alone pico-hydro power generation with constant input power. Here, the SEIG can be used to generate constant voltage and frequency if the electrical load is maintained constant at its terminals. Moreover, under such operation, SEIG requires constant capacitance for excitation resulting in a fixed-point operation. For this purpose, a suitable control scheme has to be developed such that the load on the SEIG remains constant despite change in the consumer load. In such applications, water is freely available and, hence, a simple and cheap controller has to be developed, which can operate almost unattended in remote and hilly regions. The proposed ELC consists of an uncontrolled rectifier and chopper with a series "dump" load. Proper design of rectifier, chopper, and dump load is very important for troublefree operation of ELC. In this paper, an analysis along with a design procedure for computing the rating of various components of ELC is presented for a range of SEIGs.