Tuesday, June 18, 2024

High-Voltage Resistors For EV Powertrains

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The resistor series boosts electric vehicle powertrains, meeting diverse needs in high-voltage automotive applications.

RVCA series thick film, high-voltage chip resistor. Image used courtesy of Stackpole Electronics.
RVCA series thick film, high-voltage chip resistor. Image used courtesy of Stackpole Electronics.

The RVCA, launched by Stackpole Electronics Inc. based in Raleigh, N.C., is a thick film chip resistor series tailored to the demanding application needs of 400 V and 800 V electric vehicle (EV) powertrain buses.

The RVCA series is AEC-Q200 qualified and meets standard test requirements for load life, biased humidity, short time overload, and temperature cycling, which makes it suitable for high-voltage automotive applications.

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This surface-mountable resistor series includes six models with voltage ratings from 100 V to 3000 V and comes in standard resistor package sizes from 0402 to 2512. Parts are available with resistance values from 30 kΩ to 100 MΩ and specified to 1% or 5% tolerances.

The series is used in monitoring, driving, and controlling circuits within and across the isolation boundary of an EV high-voltage powertrain bus. Applications include voltage, short circuit, DESAT protection, gate-drive, temperature monitoring, self-test, and soft-start circuits.

Pre-charge circuits are an application for high-voltage resistors in electric vehicles (EVs). EV motor inverters and similar loads have large input filter capacitors. During start-up, charging these capacitors can cause high in-rush currents that might damage electrical connectors and components. The pre-charge circuit manages this by including a high-voltage resistor with the input capacitance, extending the circuit’s time constant and limiting the capacitor charging current. Once the load capacitance is charged, the pre-charge resistor is bypassed for normal operation of the vehicle’s electric powertrain. The pre-charge circuit also reduces regular operational stress, enhancing the lifespan and reliability of the system.

The RVCA2512, the largest in the RVCA series, has a power rating of 1 W at 70°C, a maximum operating voltage of 3000 V, and an overload voltage of 4000 V. Power dissipation capabilities decrease linearly from 70°C to 155°C. The 2512 package measures 6.35 mm x 3.1 mm with a height of 0.55 mm, and all models in the chip resistor series are suitable for surface mounting in PCB manufacturing.

Nidhi Agarwal
Nidhi Agarwal
Nidhi Agarwal is a journalist at EFY. She is an Electronics and Communication Engineer with over five years of academic experience. Her expertise lies in working with development boards and IoT cloud. She enjoys writing as it enables her to share her knowledge and insights related to electronics, with like-minded techies.


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