Design of Rogowski Coil Current Sensor Integrated with Busbar and Gate Driver for 211 kW SiC-Based Three-Level T-Type Inverter

The high-power motor drives is increasingly used in the electric vehicles, railway, and more electric aircraft. The application of Silicon Carbide (SiC) devices and multi-level topologies enables higher efficiency and higher power density of the motor drive system. Traditionally, the ac load current and device current are measured separately with different current sensors, and the extra short-circuit protection is needed. Therefore, the high-current sensors and short-circuit protection circuit decrease the power density and reliability of the system. In this paper, the ac load current sampling, device current sampling, and the short-circuit protection are integrated into the Rogowski coil current sensor (RCCS) which is embedded in the gate driver and busbar. This design provides a compact and contactless current measurement, avoiding the extra bulky high-current sensors and short-circuit protection circuits. The combination with the busbar and gate driver improves the power density of the converter system. However, the integration of the Rogowski coil and the decoupling path increases common-mode (CM) noise, especially with the high dv/dt of the SiC devices. The CM model is analyzed, and the shielding is designed to suppress the CM current. The performance of the design is verified in the 211-kW 3-L SiC-based inverter.