Matrix converter is emerging to be an alternative topology for power converters, drive by persistent cost reduction of silicon devices and the development of reverse blocking IGBTs. One of the major obstacles towards commercial acceptance of this topology has been the commutation of the bi directional switches. A detailed study has been made here to understand the limitations and possible improvement of the existing current commutation techniques in this paper. A universal and synchronous commutation scheme for all the IGBTs is advised so that commutation can smoothly take place as and when required within the minimum possible time depending on the switching time of the IGBT used. The different aspects of this commutation are verified through MATLB simulink. Possibility of step less current commutation is explored.

This paper presents the methodology adopted for implementation of Peltier cooling in hermetically sealed electronic packaging units used in sub-sea vessels. In sub-sea vessels, sonar front-end electronics is packaged in hermetically sealed electronic packaging units. The thermal design of the unit is a highly challenging task considering the heat dissipation of 300W from the electronics, non-availability of chilled air for cooling and IP68 sealing requirements. Cooling fans cannot be integrated, since these units are to be placed in acoustically sensitive pressure capsule area of the subsea vessel. The electronic cooling in this unit is achieved using conduction cooling with external fins. To enhance the cooling, suitable Peltier cooling (Thermo-electric cooling or TEC) module is selected and implemented with the system. Computational fluid dynamic analysis of the unit is carried-out to study the air-flow and thermal performances with Peltier cooler. The unit is realised and the estimated temperatures validated by experimental temperature measurements on the realised unit. The measured temperatures are within the safe operating limits of the electronic components and hence the cooling design of the unit is satisfactory. It is also observed that maximum temperature reduction has occurred at 1.5A current and card edge temperature of Printed circuit board lowered by 9.28 °C by implementing Peltier cooling.