Synchronous Pulse Width Modulation for Single-Inverter Mode in Dual-Inverter Systems with Split-Switch DC Link

抄録

This paper presents the driving modes of a dual-inverter system with a split switch and addresses the voltage imbalance issues that arise during single-inverter mode operation in the overmodulation region. The dual-inverter system serves as the structural foundation; a synchronous pulse width modulation (PWM) technique, specifically applied to the single-inverter mode. In this configuration, structural asymmetries such as unbalanced current return paths and elevated common-mode voltages can reduce the efficiency, electromagnetic interference, and circulating currents. The proposed optimal synchronous PWM strategy, incorporating direct memory access, eliminates the timing jitter during real-time switching events. This approach enables precise voltage vector control and ensures consistent PWM pulse generation, which is particularly important at higher operating speeds. Compared to conventional CPU-based implementations, the proposed method shows enhanced current ripple behavior and harmonic suppression over a wide modulation index range. Simulation and experimental validations demonstrate that the method helps lower harmonic distortion and inverter power loss. Furthermore, by improving waveform symmetry, the technique indirectly aids the suppression of common-mode disturbances. This study offers a practical and scalable PWM control strategy for inverter systems that require high fidelity under real-time constraints and structural sensitivity.