A Low-Cost Current Transducer for Automotive Actuators

Electric actuators in automotive systems may require a current transducer for control purposes. A low-cost non-invasive transducer design based around a current transformer is described in this paper. The problem of droop in the output signal is addressed by controlling the current transformer's secondary terminal voltage in response to the rate of core flux change. This is detected using a tertiary flux-change sense winding. The circuit is suited for use in high-temperature automotive environments. The bandwidth of the circuit is high, allowing it to be used in peak current mode or hysteresis control schemes. Operation when sensing a 100A current pulse of 10ms duration is demonstrated and shows good agreement with the simulated performance.