How to balance EMC and safety regulations for X/Y capacitors in frequency converters?

When configuring X/Y capacitors in a frequency converter, both EMC filtering effectiveness and safety requirements must be met. X capacitors are connected across the input lines to filter differential-mode interference; their capacitance affects the filter's cutoff frequency, typically ranging from 0.1μF to several μF. Safety-certified X1 or X2 capacitors must be selected, with a voltage rating higher than the mains peak voltage and self-healing properties. The discharge resistor of the X capacitor must ensure that the voltage drops below a safe value within one second after power failure. Y capacitors are connected between the power line and ground to filter common-mode interference; their capacitance is smaller, typically 1nF to 4.7nF. Y capacitors are critical safety components and must be Y1 or Y2 grade, with a voltage rating up to several kV and an open-circuit failure mode to prevent leakage risks. The cumulative capacitance of the Y capacitor is limited by the equipment's leakage current to ground and must be calculated according to standards. In frequency converter filter design, Y capacitors are typically arranged symmetrically before and after the common-mode inductor to improve high-frequency filtering performance. When laying out the PCB, X/Y capacitors should be placed close to common-mode inductors and terminals, with short leads to reduce parasitic inductance. Eintech Electronics offers a full range of safety-certified X2 and Y2 capacitors to help inverter designs pass rigorous EMC testing while meeting safety standards such as IEC/UL.