Control of Neutral Point and Flying Capacitor Voltages in Five-Level SHE-PWM Controlled ANPC Converter

This paper presents a control strategy for a five-level active neutral point clamped (ANPC) converter using selective harmonic elimination pulse-width modulation (SHE-PWM) method. The control strategy is used to balance both the voltage across the flying capacitors and the dc-link neutral point. The strategy introduces a small change in the switching angles, which is decided upon the voltage across the lower dc-link capacitor, the voltage of the flying capacitor and the direction of the load current. Simulation results generated by MATLAB/SIMULINK are presented to confirm the satisfactory performance of the proposed control strategy. The simulated distribution profile of the semiconductor losses is also reported.