Can the PCS soft switching of an energy storage system significantly improve EMC?

Yes, employing soft-switching technologies (such as ZVS zero-voltage switching and ZCS zero-current switching) in PCS can significantly improve EMC performance. The core principle is to enable power switching devices to turn on when the voltage is zero (ZVS) or turn off when the current is zero (ZCS), theoretically eliminating voltage and current overlap during switching and drastically reducing the drastic voltage and current changes (high dv/dt, di/dt) and accompanying high-frequency noise generated by hard switching. Therefore, the conducted and radiated EMI spectrum energy of soft-switching PCS, especially at the switching frequency and its harmonics, is significantly lower than that of hard-switching topologies. This simplifies the design of output filters, reducing their size and cost. However, soft-switching circuits are inherently more complex, increasing control difficulty, and ideal soft-switching conditions are typically only achievable within specific load ranges, requiring a comprehensive trade-off between efficiency, complexity, and EMC.