Search

A circuit for adiabatically charging and discharging a supercapacitor was designed. A microprocessor sets the duty ratio of the switching transistors that control the inductor current. Changing the duty ratio in a stepwise fashion causes the output voltage to change in a similar fashion. Stepwise voltage changes enable adiabatic charging and discharging. Current measurements showed that the eight-step charging and discharging of a supercapacitor reduced the energy dissipation to one-eighth of that for a constant-voltage process. The circuit enables precise voltage control in small steps. [ABSTRACT FROM AUTHOR]

This paper describes characteristics of stepwise adiabatic charging with an inductor current by controlling switching transistors. An exact analytical resolution is obtained by using a vector comprising a voltage and a current. From a matrix calculation, the voltage and current can be written with solutions of the characteristic equation, power supply voltage, the switching ratio in the switching transistor circuit, and the number of switchings. Using the expression, the voltage and current in the stepwise adiabatic charging method can be derived clearly. As a result, it is clarified analytically that, in N-step charging, the current is reduced to 1/N so that the energy dissipation is reduced to 1/N. Next, the experimental switching transistor circuit with the controller is described, which is composed of discrete ICs. The experimental inductor current in the circuit is investigated. The measured current is reduced to 1/N in N-step charging, which is consistent with the simulated one from the theory. It is also confirmed experimentally from the average power supply current that power consumption is reduced to 1/N. [ABSTRACT FROM AUTHOR]