As the prices of the power electronic devices are getting cheaper, inverters are widely used in various applications like induction motor controllers, in relay testing equipments,uninterrupted power supplies (UPS) etc. especially in applications like in induction motor controllers and in relay testing equipments not only the frequency, but the magnitude of the voltage need to be varied. For these kinds of applications pulse width modulated (PWM) inverters are more suitable. In PWM inverters to change the magnitude of the voltage only the value of the duty factor of the switching signals need to be varied.