This paper proposes a novel power factor correction (PFC) ac -dc converter of high efficiency used in fire electric installation operated with generally rated power 2kW. The input current waveform in proposed converter is got to be sinusoidal waveform in proportion to magnitude of ac input voltage under constant duty cycle switching. The proposed converter is driven with discontinuous conduction mode (DCM), and then the control circuit requirement is simple. As results of these, the input power factor is nearly unity and the control method is simple. Also the switching devices in converter are operated with soft switching by partial resonant method. The results are that the switching power loss is very low and the efficiency of converter is high. The validity of analytical results is confirmed from some simulative results on computer and experimental results.
The stability of a new adiabatic stepwise charging circuit is discussed. Tank capacitors are connected in series between the power supply and ground. This circuit features immediate operation using a stepwise waveform, even if the tank-capacitor value is considerably larger than the load capacitance. This immediate operation is possible because stepwise voltage is formed immediately due to the voltage division by series capacitances. For the analytical discussion, we derive a voltage equation that connects the initial state and the final state after the charge-recycling process. It is proved that the eigen value of the matrix is smaller than 1. Therefore, a step waveform is spontaneously generated after many charge-recycling processes.
In order to detect plant aroma in a natural environment, we have investigated roses' aroma using an odor sensor of quartz crystal resonator (QCR).In present work, we describe experimental setup for real-time sensing of roses' aroma and feature extraction of roses' aroma sensed by QCR sensors. This method can distinguish as different aroma as human sense of smell judged for two kinds of roses. We measured one rose's aroma 3 times repeatedly in first day, second day and third day, respectively, and the result shows that rose aroma of first day is different from the ones of the other two days.