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PWM Strategies

D12.1 - Randomized Threshold-Based Power Sharing Switching Method for Cascaded H-Bridge Multilevel Inverters

Thursday, March 26, 2026
12:00 PM - 1:45 PM CT
Location: Hemisfair Ballroom
This paper presents a threshold-based pseudo-randomized switching strategy for Cascaded H-Bridge (CHB) inverters that enables smooth, continuous, and current-sensor-free power sharing among modules, even under unequal SoC, different energy capacities, or mismatched DC-link voltages. The method exploits redundant switching states in Phase-Disposition PWM (PD-PWM) and uses a user-defined Threshold parameter to probabilistically select states, regulating each module’s activation frequency and power consumption. This minimizes switching imbalance, avoids extra sensing hardware, and keeps implementation simple. A compact analytical model links the threshold to the resulting power distribution, showing a predictable, nearly linear mapping. The strategy is validated through simulations on a 10-kW two-cell CHB inverter and experimentally on a scaled 5-level SiC-based prototype. Results confirm accurate tracking of desired power-sharing ratios in both balanced and unbalanced conditions.