Abstract

The shift from combustion engines to electric vehicles (EVs) seems inevitable as governments around the world commit to environmental sustainability goals and the automotive industry plans to invest more to accelerate vehicle electrification. The capacity of DC fast-charging stations has increased significantly in recent years. Where the standard was once 150 kW, capacities are now 350 kW and beyond — and the improvements continue. To get to 350 kW and above, a common technology is to stack modules with 20 kW to 40 kW in parallel and perform load balancing of those modules in parallel in a higher level control loop. The current and voltage-sensing technology plays an essential role in the power module control loop of DC fast-charging stations. This application report looks into design considerations for current sensing in EV charging applications, especially with a focus on the gain error, offset, bandwidth, and latency concerning system performance.