Single phase transformerless wide range ac boost voltage regulator based on z-source network

This paper proposes a new type of voltage regulator based on single-phase z-source converter that compensates wide range voltage variations. This is not only capable of compensating variations at a much higher bandwidth but also boost the voltage level even twice that of input supply. The proposed system employs a pulse width modulation (PWM) z-source ac–ac converter along with a simple closed loop control. The input rms voltage can be sensed and divided by the desired value to find the instantaneous value of gain, which mathematically calculates the possible duty ratio of PWM switching signal based on the open loop characteristics of the converter. High speed IGBTs are used as bi-directional switch of the ac–ac converter and the circuit ultimately can easily and steadily maintain regulated voltage supply to the end user. The whole system operating principle and analysis are provided. Simulation results show the improvement of voltage disturbances both in voltage rise and fall conditions.