Three-Level Control of DC Side Voltage Balance of Cascaded H-Bridge APF

The stable operation of H-bridge APF is based on the equilibrium of the DC side capacitors voltage. This thesis proposes a three-stage method for equalizing the voltage of capacitance. This control strategy significantly improves the pressure level of the APF. And in order to improve the accuracy of current output, on the basis of three layers of DC side control, the repetitive control is added. Finally, the voltage is controlled near the given magnitude. Then, the simulation results show that the three-stage method is very effective. which provides a basis for cascading APF applications to higher voltage levels.