STRAY INDUCTANCE EXTRACTION METHOD BASED ON INTERRUPTING TRANSIENT PROCESS FOR POWER ELECTRONIC COMPONENT IN HYBRID DC CIRCUIT BREAKER

The power electronic component (PEC) is the key part that determines the breaking capacity of hybrid DC circuit breaker. The internal stray inductances have significant impacts on the interrupting performance of PEC due to the extremely high current rate when the component interrupts the short circuit current. Firstly, this paper analyses the commutation stages of the diode-bridge component during the turn-off process. The commutation loops of the first and the second commutation period are depicted and the equations for stray inductances extraction are given. Then, a test platform is built for 10 kA interrupting experiments of PEC. By analysing the detailed current and voltage waveforms of the two commutation stages, the optimal periods of the stray inductance extraction for the two commutation loops are pointed out and the stray inductances are extracted based on the experimental data. Finally, the 3D protype of PEC is given and the reasons for the difference in the extraction results of the first commutation loop utilizing two transient processes are listed.