Voltage Control Of Induction Generator Based SVC

It is hard for induction generator to keep the terminal voltage constant when load changes. The traditional way to solve this problem is through switched capacitor to compensate reactive power, but it in fact cannot adjust the terminal voltage continuously. Static Var Compensator (SVC) is able to regulate the reactive power smoothly and dynamically with a simpler structure and convenient control mode, which is appropriate to be used in the voltage control of induction generator.Based on the transient mathematical model of induction generator, the principle of voltage control in this machine can be clearly illustrated with formula derivation. When load changes, the terminal voltage can stay constant with the adjustment of reactive power absorbed or generated by compensator. Based on the steady state mathematical model of induction generator, the effect of equivalent susceptance of SVC on terminal voltage is analyzed, and the calculation of SVC capacitance is also proposed.The control strategies of SVC are introduced and compared. And the most proper control mode for voltage control of induction generator is determined with sufficient consideration of its characteristics. In view of the fact which thyristor controlled reactor (TCR) introduces specific harmonics into power grid, a corresponding LC filter is designed to eliminate the specific low-frequency harmonic for a higher quality of current and voltage. The calculating method for filter parameters is also presented.According to the selected control method for the voltage control of induction generator, the final design proposal of circuit would be determined, which has passed the examination by experiment. The hardware circuit includes the voltage sample circuit and its power supply, the SVC main circuit, the filter, the zero-crossing detection of thyristor digital triggering circuit, and so on. Based on the hardware of voltage control system in induction generator, the main program and interrupt sub routines of TMS320F28335are accomplished with C programming language.The reliability of voltage control system of induction generator is verified from both simulation and experiment. And the effects of different control strategies are compared through analysis of their results. Solutions are put forward according to the existent problems.