Design and analysis of the power electronic transformer for power quality improvement

Transformer is an indispensable component of power system which performs many functions such as voltage transformation, electrical isolation, noise decoupling and power quality improvement. However, at low frequencies (60/50 Hz), it is a bulky and expensive component. In this paper, the concept of electronic transformers is further extended and explored for its suitability in power systems. Though from the perspective of input/output behavior, the electronic transformer and the conventional transformer are identical but the PET has reduced size, losses, higher efficiency, improved voltage regulation and reduced voltage sag in comparison to those of conventional transformer. In the proposed design, three phase full wave converter and inverter are incorporated in both primary and secondary sides of the high frequency transformer. The PWM (pulse width modulation) is used for switching which manages synchronism between input and output and suppresses harmonics. The matrix converter is used in the proposed design which uses SVPWM (space vector pulse width modulation) for multiple switching. The SVPWM ensures maximum voltage transfer without harmonics in the output. The design and analysis of the proposed model of PET is done by using MATLAB-SIMULINK. It can be inferred from the steady state analysis of the simulation results that the PET has better voltage regulation than that of the conventional transformer.