Low-cost high-bandwidth current transducer for automotive applications

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 (CT) is described in this letter. The problem of droop in the output signal is addressed by controlling the CT's secondary terminal voltage in response to the 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 100-A current pulse of 10-ms duration is demonstrated.