Improvement of power factor using the extinction angle control method

Abstract

Basically, the power factor (PF) is defined to be the ratio of real power (P) to the total apparent power(S). The phase shift that is found in between the current and voltage waveforms cause the changes in Power factor. This phase shift is due to the load connected on the end therefore depending on the type of load (inductive, capacitive) the phase lag and lead respectively. In this paper we have proposed an idea on improving the power factor of a system using a different approach which is done with the help of power electronic devices like MOSFET & SCR instead of using capacitor banks. Extinction angle refers to the time interval from the instant when the current through an outgoing thyristor becomes zero (and a negative voltage applied across it) to the instant when a positive voltage is reapplied. It is expressed in radians by multiplying the time interval with the input supply frequency (ω) in rad/sec. In this proposed model by controlling this extinction angle power factor is improved and this is called as extinction angle control. The input current's waveform is changed by setting on/off the MOSFETs & SCRs at certain times. The turning on/off leads to increase in phase in the fundamental current wave. This setup of power factor correction can be used as a redundant one, because in capacitor banks replacements take time and it costs more. so, this is the method through which the power factor correction is made cost efficient and easy for the users for replacements. By doing this, the power factor is improved. The above-mentioned system was executed in MATLAB Simulink software and convincing outcomes were acquired.