High voltage inverter remote discharge

Every EV traction inverter requires a DC link active discharge as a safety-critical function. The discharge circuit is required to discharge the energy in the DC link capacitor under the following conditions and requirements: Power transistor on, off control using the TPSI3050-Q1.

High-voltage active discharge refers to the process in which the electric energy in the high-voltage capacitor is quickly (generally 1 ~ 2 s) released to a safe level (the high voltage is reduced to below 60 V) through a special discharge circuit and control strategy after the high-voltage system of the EV is powered off.

Abstract: when an Electrical Vehicle (EV) encounters an accident or the vehicle is taken to a service station, the DC-link capacitor in the inverter must be discharged to ensure safety of both the passengers and the operator.

To control the voltage so that the voltage does not exceed 50 V (touch safe), the auxiliary power supply has to turn on and power up safety-relevant circuits that can discharge the DC link caps (active discharge) or actively short circuit the motor. Every EV traction inverter requires a DC link active discharge as a safety-critical function.

Weight and power density – The wide band-gap switch and powertrain integration are the key technologies enabling high-power density inverter design. The inverter power density target of OEMs continues to, for example, 100 kW/L in the US market by 2025. The use of SiC enables 800-V DC bus voltage, reduce the current rating and wiring harness.

Image used courtesy of Adobe Stock High-voltage DC links are central to a wide range of power electronic systems in electric and hybrid vehicles—including inverters relying on large capacitors (e.g 1 mF) to stabilize the voltage, reduce ripple, and support efficient control and operation.