Design of a parallel active common mode current compensation circuit

A parallel active common mode current suppression scheme is present. Two different compensation circuits, which are direct parallel and indirect parallel compensation circuits, are introduced in this research. The common mode current equivalent model of the single-phase half-bridge inverter with two different compensation circuits is studied. The design principle of two compensation circuits is illustrated briefly. And two factors that influence the suppression effect of compensating circuit are analysised. An experimental set-up of the single-phase half-bridge inverter with parallel active compensation circuits is established. The test results validate the design principle of compensation circuits and prove that the output compensation current has the same scale and anti phase of the common mode current produced by bridge-arms of the inverter.