An Efficient Resonant Pole Inverter With Reliability Improvement of Soft-Switching in the Case of Open Failure of Any Auxiliary Device on Each Bridge Arm

For the sake of the performance improvement of soft-switching inverters, the paper designs an efficient resonant pole inverter. Main switches in the designed inverter can attain zero-voltage switching with the low peak voltage and current stress, which is conducive to the low loss of main switches. Moreover, the striking feature of the designed inverter different from existing resonant pole inverters is that two sets of independent symmetrical auxiliary circuits on each bridge arm are not jointly involved in the operation in a switching cycle, and that they are alternately involved in the operation based on the different direction of load current, not only providing the condition of zero-voltage switching for main switches but also improving the reliability of soft-switching of main switches in the case of open failure of any auxiliary device. The paper provides the detailed interpretation on each working status during a switching cycle. Experimental waveforms manifest that main switches can attain zero-voltage switching. The efficiency test at rated operation state also manifests that the efficiency of the designed inverter is up to 99.1% without any failure of auxiliary devices and 98.2% with open failure of an auxiliary switch on each bridge arm, confirming that the designed inverter has superiority over the comparison object in the field of efficiency even if open failure of an auxiliary switch on each bridge arm occurs in both of them. Hence, the alternate operation of symmetrical double auxiliary circuits based on different direction of load current in the designed inverter is especially beneficial to reliability improvement of soft-switching with open failure of any auxiliary device.