PERFORMANCE INVESTIGATIONS ON VOLTAGE CONTROLLED SELF-EXCITED INDUCTION GENERATOR

Abstract

Now a days world is hungry for power. Every country develops more and more energy from its each and every possible resource for driving their economic and social growth towards new heights. India is no exception in that. For that so many scientist and engineers are working in finding more economic and viable power generating solutions which are also concerned with green and clean energy and also for reason of increasing cost of fuel. Renewable sources fits in this requirements. As of now India's most power (about 70%) is generated through thermal power plant which uses coal and we have huge unexplored potential of wind and mini and micro hydro power in different parts of country. Power in every village is also a dream up to now because their geographic locations and other infrastructure problems. For this reason country like ours there are huge potential and demand for small isolated power generation systems. The squirrel cage induction generators are widely used for low and medium power generation. These are ideally suited for non-conventional energy generation and have number so advantages over synchronous generator like low cost, simple construction, ruggedness, and brushless rotor, absence of DC source, maintenance-free nature and self-protection against short circuits. In a stand-alone operation, the three-phase induction generator operates in the self-excitation power generation mode when a capacitor bank connected in parallel with its stator terminal ports and driven by a renewable energy prime mover as wind turbine. However, they must deliver power to the consumer with acceptable quantity in terms of voltage, frequency, and waveform. Self Excited Induction Generator is suffered from change in voltage and frequency with change in loading and speed of prime-mover SEIG requires suitable controllers to be developed and the crucial function of such controllers would be to provide required Variable Capacitive Reactive power (VAR) to maintain constant voltage across the load at all time. A new controller for variable speed, constant voltage operation of induction generator, in self-excited mode has been developed in this dissertation; a simple control III scheme is proposed for self-excitation control of induction generator. In this scheme, only the controller current is sensed and forced to track the reference current. The controller does not require any real time mathematical computation. The control technique also does not require information about rotor speed and position. This eli~m inates need for mechanical sensors, minimizing hardware and reducing overall cost. Direct sensing of the controller current enables protection of the controller from over-current. Low rating current sensors are required for this scheme as the sensors have to sense only the controller current. The complete controller with CC-VSI and associated circuitry has been developed. All hardware components are working in co-ordination. The voltage buildup process in SEIG has been simulated in MATLAB Simulink software and the operation of SEIG is experimentally verified. The CC-VSI is simulated. The results of simulation and hardware implemented works as expected. IV