A novel controller for a voltage source sine wave transformerless boost inverter

In this paper a transformerless voltage source sine wave inverter is proposed. A previously developed tri-state boost converter is utilized for the stepping up operation. In this topology the dynamic response of the inverter is increased, by avoiding the right hand plane zero in the converter's small-signal control-to-output transfer function when operating in the continuous conduction mode. The reference voltage for the tri-state boost converter is determined from the measured output voltage of the sine wave inverter and the calculated instantaneous value of the sine wave. The inverter with the tri-state boost converter and the inverter with a classical boost converter with voltage mode control and current mode control are compared for the dynamic response and efficiency. The analytical work of the design has been verified using a simulation. Furthermore, the boost converter is implemented in hardware to verify the boost inverter calculations. The current mode control and the tri-state logic hardware implementation are ongoing, and it is presented as future work. Finally, two user selectable modes are proposed for the inverter optimized for dynamic performance or efficiency.