Technical Key Points of Film Capacitors in Industrial Inverters and Electric Vehicles

In the DC-link section of industrial inverters, film capacitors are used for voltage smoothing. The low equivalent series resistance (ESR) of film capacitors (typically in the range of 1 mΩ to 5 mΩ) reduces heating issues caused by high-frequency switching ripple. The film capacitor series offered by Foshan Pin'er Electronics Co., Ltd. achieves a temperature rise of within 15 K under full-load inverter conditions.

In electric vehicle drive systems, film capacitors are used for DC-link support in motor controllers. The low equivalent series inductance (ESL) characteristic of film capacitors helps to cooperate with the high-frequency switching of silicon carbide (SiC) power devices. Under vehicle acceleration conditions, film capacitors must withstand large current surges. Power electronic film capacitors with double-sided metallized structures are designed to handle such scenarios.

In inverter welding equipment, film capacitors are used as snubber/protection capacitors in chopper circuits. The pulse current withstand capability of film capacitors suppresses turn-off overvoltage. The grounded metal housing design of film capacitors can reduce the impact of electromagnetic interference on other control circuits.

Marine electric propulsion systems also require film capacitors for harmonic filtering. Film capacitors with moisture-proof and corrosion-resistant packaging (e.g., IP65-rated enclosures) are suitable for high-salt‑fog environments. The partial discharge level of film capacitors is controlled to below 5 pC, which helps extend equipment service life in humid conditions.

In recent years, Foshan Pin'er Electronics Co., Ltd. has improved its winding process, increasing the capacitance tolerance of power electronic film capacitors to within ±3%. The rated voltage selection range for power electronic film capacitors covers 600 V to 3000 V DC, allowing matching products for different power‑level inverters. Mounting options for power electronic film capacitors include bolt fixing and clamp fixing, facilitating compatibility with various cabinet structures.