Noise evaluation, two switch resonant DC link-assisted double converter system and commutation control to improve loss

The novel control method of reducing the power losses in the soft commutation circuit of this ARDCL method with two switch quasi-resonant circuit was proposed for three phase double converter with a single resonant snubber. It was confirmed that all the active power switches in the main and auxiliary circuit could achieve the soft switching commutation within the wide operating range from a light load to the ratings load. Moreover, the boost current was able to be substantially decreased to a minimum value necessary to make a main switch ZVS in this control strategy. This double converter system could improves the actual efficiency from 86.9% to 88.7% for the hard switching method, and has also improved the conduction noise by about 20 dB in the experimental feasible system of 10 kVA. It was verified that this double converter circuit composition is simpler than the other soft switching methods because the circuit components and power semiconductor devices and the detector and their related interfaces are not added. In. addition, because the main active power switch losses could be substantially decreased about one half as compared with the hard switching double converter system, this switch and the cooling heat sinks could be also miniaturized. The double converter system are cost effectiveness is high. This soft commutation double converter implementation is going to be practicable, because of the excellent merit. Finally, the switches of the experimental system used high-speed IGBT as compared with the hard switching method. This soft commutation method makes all the switches soft-switching. Therefore, if the trench gate IGBT with the low saturation type is used, much higher efficiency can be achieved in this double converter and are able to have practical effectiveness.