Design and Control of Multi – Input Multi – Output DC-DC Converter for Neutral Point Clamped Inverters

Abstract

In this study, multi-input multi-output DC/DC converter topology is presented for both multisource operation and voltage unbalancing of Neutral Point Clamped (NPC) inverters. Multisource operation is provided with multi-input feature of proposed converter model. The unbalanced capacitor voltages in NPC inverter leading to increase the harmonics are compensated on the DC side by the multi-output feature of this topology. PI controllers are utilized to control the capacitor voltages and power flow of grid connected inverter. Simulation studies are performed in Matlab/Simulink platform to verify the theoretical background and performance of the proposed topology. Simulation results show that, produced power from two input sources is successfully transferred to grid through the proposed converter structure and NPC inverter. Even if NPC inverter disturbs the equality of capacitor voltages, the voltage balance is maintained by the controllers and proposed converter model. The results that are obtained under balanced and unbalanced conditions show that, the proposed system considerably decreases the harmonics.

Keywords

• Multi Input – Multi Output DC-DC Converter
• Neutral Point Clamped Inverter Voltage Control
• Voltage Control