A Study on the Reduction of Switching Power Loss in Quadratic Boost Converter for Energy Harvesting of Switch Board

This paper proposes a passive snubber for the quadratic boost converter to reduce the switching turn-on and turn-off losses. The proposed snubber consists of one inductor, two capacitors, and two diodes. The snubber inductor controls the current slope of the switch, and the snubber capacitors reduce the maximum voltage of the switch. Using the LT-Spice simulator, the switching loss of the proposed converter was compared with a conventional quadratic boost converter, and the simulation results show that the switching loss of the proposed converter was improved by 21.3% from that of the conventional quadratic boost converter. A 15 W proto-type was manufactured and compared with a conventional quadratic boost converter at VSUBIN/SUB = 4.2 V, VO = 24 V, PSUBout/SUB = 1 ∼ 15 W, and fSW = 290 kHz. The experiment confirmed that the efficiency of the proposed circuit was improved by 6.09% at PSUBout/SUB =1 W and 1.90% at PSUBout/SUB = 15 W, and the switch driving temperature was lowered by 4.7℃ at PSUBout/SUB = 8 W and 3.9℃ at PSUBout/SUB = 15W compared to the conventional quadratic boost converter. This result shows that the proposed circuit is suitable for a structure to reduce the switching losses of conventional quadratic boost converter, and it can be expected that it could be used in various power applications requiring a high input to output voltage conversion ratio.