How to ensure EMC stability of PCS (Power Conversion System) in high and low temperature environments?

To ensure stable EMC performance of PCS over a wide temperature range (e.g., -40°C to +70°C), the impact of temperature on component and material characteristics must be considered. Key points:

1. Component temperature characteristics: The permeability and losses of magnetic components such as common-mode inductors change with temperature; the capacitance and ESR of capacitors also drift; the characteristic curves of filters shift. Materials with stable temperature characteristics must be selected, or sufficient margin must be ensured in the design for extreme temperatures.

2. Shielding materials and connections: The elasticity and conductivity of shielding materials such as conductive pads and springs change with temperature; wide-temperature-range products must be selected. Metal seams may affect contact continuity due to thermal expansion and contraction.

3. Device operating point variations: Temperature affects the switching characteristics and on-resistance of semiconductor devices, potentially altering the noise spectrum.

4. Thermal design assurance: Good thermal design ensures all components operate within their allowable temperature range, which is fundamental to stable performance. EMC testing under high and low temperature environments is necessary to verify the robustness of the design.