Effect of adding impedance for current balancing on the vacuum arc commutation characteristics of DC microgrid hybrid circuit breakers.

To achieve current balance between parallel‐connected insulated gate bipolar transistors (IGBTs) of a DC microgrid hybrid circuit breaker (DC MHCB), it is a simple and effective method to add impedance in parallel‐connected IGBTs, but this will also affect the vacuum arc commutation of the DC MHCB. The focus of this paper is the effects of adding impedance on vacuum arc commutation characteristics. By constructing a simplified model of vacuum arc commutation in the case of adding impedance, the effect of adding impedance on vacuum arc commutation is theoretically derived. The test circuit of vacuum arc commutation is established, and the effect of adding impedance on vacuum arc commutation in the presence or absence of the externally applied transverse magnetic field (TMF) is investigated using the electrical measure. The theoretical formula and related formulas of the effect of adding impedance on the duration of vacuum arc commutation are obtained. A method combining adding impedance and an externally applied TMF is proposed. The constraint formula for adding impedance during vacuum arc commutation is obtained. The main factors that limit the value of adding impedance are obtained. Research on the effect of adding impedance on vacuum arc commutation characteristics can provide theoretical guidance for the application of the method of adding impedance in a DC MHCB. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]