A Modified One Cycle Control of VIENNA Rectifier for Neutral Point Voltage Balancing Control Based on Cycle-by-cycle Correction

This paper presents a modified one cycle control (OCC) for VIENNA rectifier to balance neutral point (NP) voltage and suppress its oscillation by introducing the concept of redundant vector in space vector pulse width modulation (SVPWM) into OCC. By changing the phase of the drive signals, an additional switching state is introduced to minimize the average neutral current over a switching cycle and it can be proved that the additional switching state does not introduce additional harmonics to AC circuit by analysis the inductance voltage of the OCC-based VIENNA rectifier. Unlike SVPWM, all the calculations require only three-phase currents and capacitance voltages as parameters and it can be achieved in abc coordinate system, so that the proposed control strategy can be easily implemented by a digital controller without complex calculations. The feasibility and performance of the modified OCC strategy has been validated by simulations in MATLAB/Simulink and experimental results.