Theoretical and Simulation-Based Validation of Switching Counts in Cascaded H-bridge Five-Level Inverters with Carrier Phase-Shifted SPWM Towards Orbital Power Systems for SpaceX AI Data Centers

To address the challenge of indistinguishable switching events in timing diagrams of pulse width modulation (PWM) under high carrier frequencies for modern multilevel inverters, e.g., cascaded H-bridge (CHB) inverters, this research introduces a robust calculation framework for identifying the Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) switching counts by integrating theoretical derivation with low-frequency carrier simulation. Focusing on a single-phase five-level CHB inverter controlled by carrier phase-shifted sinusoidal PWM (CPS-SPWM), this work establishes a verbalized relationship where the switching frequency is determined by the ratio of the carrier and modulation frequencies. Validation through a reduced-carrier simulation demonstrates that the scaled results are highly consistent with theoretical predictions (0% deviation). This approach effectively eliminates the visualization constraints associated with high-frequency waveforms and provides a precise quantitative basis for switching loss assessment, demonstrating significant engineering value and application potential in guiding the modulation strategy optimization for multilevel inverter-based power electronic subsystems targeting motor drives for the renewable energy industry towards the net-zero vision. The validated framework not only supports loss assessment for terrestrial renewable energy systems but also extends to the design of efficient, high-power-density power electronic subsystems for emerging solar-powered orbital applications, e.g., SpaceX's AI satellite data centers, where reliable power management via accurate switching loss prediction is paramount towards space-based AI infrastructure.