Voltage regulation using delta PWM inverter fed series compensator

Abstract

In this thesis a method of generation of PWM signal, called Delta PWM has been proposed amongst the many existing complicated methods to generate the same for use in series voltage regulation of utility supply system. Using this Inverter in series, the line voltage compensation in a supply system can be achieved in a relatively simpler way. The delta modulation scheme is a self carrier generating and the carrier is stable which is important in the designing of the filter of the rectifier inverter system used in series compensation system. A simple control technique for the senes voltage compensation scheme has been proposed in this thesis. The scheme is based on phase addition and determination of required phase angle is carried out using analogue feedback control circuit. A microcontroller based system may be engaged to generate the delta PWM signal directly shifted as required. Method of analogue computation is discussed. A theoretical approach leading to the formulation of algorithm applicable for microcontroller based PWM signal generation has been presented. Simulation was carried out using both the series and parallel filters separately and the results were presented. The Fourier analysis was carried out to observe the amplitudes of all the harmonics in each case. The results of both the series and parallel filter for eliminating of harmonics have been studied. This work provides an easy method of voltage regulations of a utility power supply with improved performance, easy implementation and controls. It will also ensure reliable operation with fast dynamic and steady state response of the control scheme and power circuits for phasor addition of voltage are almost instantaneous operating in nature.