Research on the Measuring System for IGBT Current Distribution

Press Pack IGBTs play a critical role in cutting short-circuit currents in the HVDC flexible system and have been applied widely due to their high operating speed and low cost. However, the current imbalance between sub-modules in parallel is usually unavoidable which can lead to failure of the entire device. Therefore, it is very important to measure the current flowing through sub-modules in the reliable test. A method for measuring the current through the sub-modules inside the Press Pack IGBT is proposed in this paper. An enameled wire was wound on a insulating frame to form a coil current sensor which is connected to the integrator circuit to obtain the measurement current waveform. The Maxwell was used to calculate the coil inductance in order to determine the number of coil turns and design the integrator. Finally, The current curve measured by this current coil sensor was considered to that by the commercial sensor to verify the feasibility of this measuring method.