Pulse-width-modulated (PWM) voltage source inverters (VSI) have been adopted widely in traction and grid-tied applications due to their increased efficiency and controllability. The well-known trade-offs include high-frequency common-mode (CM) noise, which excites the parasitic capacitances and leads to undesired ground currents, bearing degradation, and EMI compliance challenges. Conventional solutions rely on bulky common-mode chokes, Y-capacitors, or active filters that are typically adopted post-design phase, which increase the overall system's cost and complexity and still do not fully suppress Common-mode currents (CMC). This paper focuses on studying the Single-Stage Buck-Boost (SSBB) converter, which features a non-switching common-mode Voltage (CMV) resulting in minimal CMC. Hardware experiments confirm the analytical results in terms of reduced EMI challenges where the measured CM current is reduced by more than an order of magnitude compared to a VSI under identical operating conditions. The paper also includes a detailed equivalent high-frequency EMI models of the converter and provide a direct comparison with a VSI incorporating an EMI filter across key parameters.
