This paper presents a single-phase photovoltaic (PV) inverter with transformerless type, which is more efficient and reliable with low cost and size as compared with the traditional PV inverter which needs a step up transformer between inverter and grid. A boost DC-DC converter is used to put into effect the MPPT algorithm for attracting the maximum control from a PV panel. Perturb& Observe (P&O) method is used as a maximum power point tracker due to its simplicity. A single-phase MOSFET transformerless inverter is introduced for the PV microinverter systems using phase leg configuration. The PWM technique and circuit operation principle are described. The differential mode and common mode voltages model is introduced and analyzed for circuit design. The system is simulated using PSIM program to verify the suggested transformerless photovoltaic microinverter. The simulation results show the validity of the designed system.

This research presents a study, modelling and simulation of the piezoelectric material work as filters (piezoelectric filter) used to eliminate the harmonics in power electronic circuits, high order harmonics are generating due to the high switching frequencies and circuit equipment, detailed simulation is achieved for the piezoelectric filter tested in full-bridge DC/DC converter circuit with resistive load works as dc power supply (12 to 48 volt). As a result, the uses of piezoelectric filters have a great impact on harmonics elimination, which leads to reduce the overall total harmonic distortion leads to increase the efficiency, as well as the output voltage from the dc power supply remain constant by varying the load resistance over a wide range. The dc power supply circuit including the piezoelectric filter has been simulated using PSIM (V9.1) power electronic circuit simulation software.