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Switching Current Measurement Based on Power Module Parasitics

double-pulse test
Fig. 1. Experiment setup of the double-pulse test using the proposed current sensor.
  Current and voltage sensors play important roles in electric drive systems. Switching current sensors help protect the power MOSFET module from a short-circuit event. Thus, good sensor design increases the reliability of the overall electric drive system.
  In recent years, some advanced techniques, which are suitable for high power MOSFET modules, have been developed. In some research works, the Rogowski coil is integrated into the gate driver for both short-circuit protection and current reconstruction. However, the PCB design of the on-board Rogowski coil is complex, and the coil also consumes a large space in the circuit. The current sensing for short-circuit protection based on parasitic inductances of the power MOSFET module is one of the simple yet effective methods. Although a good protection can be achieved, the current waveforms cannot be recovered due to the high-pass filter characteristic that rejects all low-frequency components in the measurement current.
  This paper proposes a current sensor design based on the power module’s parasitics. The experiment setup of the double-pulse test using the designed current sensor is presented in Fig. 1. Besides the simplicity in the configuration, the method provides a good switching current sensing, as shown in Fig. 2.

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