NEXT GENERATION TRACTION INVERTER: SAFE, EFFICIENT AND COMPACT

BORGWARNER HAS IMPROVED THE PERFORMANCE, INTEGRATION AND RELIABILITY OF ITS INVERTER TECHNOLOGY BY REDESIGNING THE POWER, COOLING AND CONTROL SYSTEMS AND SIMPLIFYING PRODUCTION.

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As electric propulsion continues to gain market share against the internal combustion engine, it is vital to maintain this momentum by refining technologies in preparation for the next generation of electric drives. Major components such as batteries, inverters and electric motors must become more compact while offering improved safety and efficiency. This paper explores the measures taken by BorgWarner to redesign the traction inverter to meet the latest market demands..

DESIGN TARGETS

Taking into account the requirements of both passenger cars and mediumpower commercial vehicles, an 800V DC system was indicated with RMS phase currents of 650A peak/400A continuous to cater for power ratings of up to 400kVA. The power output could be scaled down by modifying the number or size of certain components; for example, reducing the Silicon Carbide (SiC) die count or capacitor footprint.

Inverter performance and efficiency should be stable in an environment of (-) 40 to (+) 85°C and at altitudes of up to 5,000m. An IP67rated enclosure would protect against ingress of dust and water.

The electrical and dynamic safety of a traction inverter are dominant concerns, notable hazards being the high voltage and current values, and the potential for strong acceleration/ deceleration. BorgWarner set out to achieve Automotive Safety Integrity Level (ASIL) D, the top safety level defined in the ISO 26262 standard. The company's newly-developed Inverter System Safety ASIC (INSSA) would play an important role in reaching this design target.