Analog Basis, Low-Cost Inverter Output Current Sensing with Tiny PCB Coil Implemented inside IPM

This paper proposes a practical current sensor integration in the intelligent power modules (IPMs) using simple PCB Rogowski coil sensors. The PCB sensors produce signals that proportional to the high frequency switching current from high and low side IGBTs. Then with only general-purpose Op-Amps and photo-couplers based integrator and sample and hold (S/H) circuits reproduce output current of the inverter. Specifically, the “envelop tracking” method has successfully proved on an experimental inverter setup. A significant accomplishment of an improved new analog circuit is the measurement during narrow pulse width around unity modulation index that leads to higher inverter output power.