DESIGN AND DEVELOPMENT OF ELECTRONIC LOAD CONTROLLER FOR SINGLE PHASE INDUCTION GENERATOR

Abstract

In case of small isolated generating unit driven by non-conventional energy sources such as small hydro and wind etc. The use of conventional control mechanism is not advisable option because of initial investment and performance factors. If there is no mechanical governor, the Electronic Load Controller can be used to maintain the generator output voltage and frequency, irrespective of the amount of load connected to the generator. It does this by automatically dissipating any surplus power produced by the generator in additional loads, known as ballast load. With the variable mark space ratio chopping technique, the amount of power to be dissipated in the ballast load is controlled by varying the mark space ratio, before the ballast is switched on by means of MOSFET or IGBT arrangement. The variable mark-space ratio chopping technique realised by analog circuits and different hardware modules are designed, fabricated and tested for voltage sensing circuit, power supply and voltage reference circuits, triangular waveform generator, and comparator and IGBT gate-drive circuits. In addition to this, a possibility of realizing the PLC based controlled system also explored with suitable ladder diagrams, which have been developed and tested for: firing pulse (1 kHz) generation, sensing/measurement of generator voltage, and frequency measurement and providing over/under frequency protectio