Design of a microcontroller based three phase inverter

In this thesis, design and implementation of microcontroller based 3x200 W, 50 Hz three-phase inverter has been presented. The design of the three-phase sinusoidal pulse width modulation (SPWM ) inverter model has been simulated by using electronic circuit design software named as Proteus. SPWM which is the most common method in inverter applications has been utilized in our design. SPWM method is characterized by fixed amplitude pulses with various duty cycles for each period. The widths of these pulses have been generated by microcontroller unit with sine Look-Up Table (LUT) in order to obtain inverter output voltage control and reduce its harmonics. SPWM as unipolar has been produced by ATmega 2560 microcontroller. The microcontroller-based three-phase inverter has 4 power MOSFET in each phase with H-Bridge topology after external shoot through circuit and MOSFET driver circuit. Unfiltered output of H-Bridge has been increased by step-up transformer. After transformer, the unfiltered output has been passed through Low-Pass Filter for having pure sine wave in 50 Hz. The transformers are connected in Y connection for stand-alone 3-Phase network. Finally, the hardware design for three-phase voltage switching SWPM inverter has been tested for different load conditions and calculated the efficiency for the best operational parameters. The test results showed that the design was successful.