Boost type series resonant converter with flexible structure for power supplies

Relevance. Geophysical research quality highly depends on power supply system, which, in its turn, has to provide uninterrupted power, for instance by means of accumulator battery. Specifically, continuity of supply is important for borehole logging during directional drilling which requires autonomous (self-powered) equipment. Converter powering geophysical equipment operates at high temperatures, where heat removal is impeded, makes the enhancement of the converter efficacy of utter importance. In that regard boost type topologies converting a part of a total power flow are preferred, especially in non-isolated power supply systems. However hard commutation in such topologies impairs an efficiency thus justifying development of boost type resonant converter. The aim of the research is to develop resonant boost type converter of high efficiency and to investigate one's power and control properties. Methods: electrotechnique fundamentals, linear equations theory, along with the modern simulation software, computational and mathematical modeling techniques. Results. The authors have analysed DC-DC resonant bridge converter with the boost link in voltage regulation mode powered by the battery as well as in a battery charge mode. The paper demonstrates high efficiency of a narrow battery voltage range. The control mode has substantial influence on operating parameters. Variable frequency PWM keeps relatively low value of operating current thus providing maximum efficiency. Frequency variation required to stay in soft commutation mode by guaranteeing current direction at turn-on instance. Soft commutation transitions are however different for the inverter and synchronous rectifier. Inability of boost topology to limit output current at overload is shown and topological solution is proposed to overcome it using auxiliary switches. The results are proven using hardware prototype. The paper introduces the conclusions as well as discussion of the results.