Output-Current Measurement of a PWM Inverter with a Tiny PCB Rogowski Sensor Integrated into an IGBT Module

Inverters used in motor-drive and grid-connected applications usually employ current sensors at the output terminal because they have to control the output current. Existing current sensors like the Hall sensor and the current transformer are a constraint to reduce the volume and cost of the inverter. This paper proposes an output-current measurement method of a PWM inverter using a tiny PCB sensor that is based on the so-called Rogowski coil and can be integrated into an IGBT module. The method utilizes the switching current of the lowside switch for reproducing the output current, which allows using the PCB sensor because the switching current consists of high-frequency components. The method uses a single PCB sensor per leg and takes the polarity of the output current into account. Experimental results using a half-bridge sinusoidal PWM inverter verify that the proposed method measures the output current including its fundamental frequency component, switching ripple one, and polarity.IEEE Energy Conversion Congress and Exposition (ECCE 2019), September 29-October 3, 2019, Baltimore, Maryland, US