From the environmental point of view, low power consumption and low noise have been required in recent years and new soft switch-mode power supply which has been developed to meet these two requirements will be presented in this paper. The noise level of this new switch-mode power supply is lower than Class-B of CISPR by 30dB or more and the leakage current which tends to be increased in a low-noise power supply can be suppressed to 0.18mA or less to improve the efficiency about by 5%, compared with conventional power supply. This paper will report the operating principle of the SMZ system, operational analysis, oscillating frequency characteristics, efficiency characteristics, noise data etc, and also will describe the mechanism how the noise produced.
This paper describes techniques that Japanese power electronics engineers can use to improve the quality of their technical papers written in English and the accompanying technical presentations. These techniques are based on the experience that the author has gained by participating in international conferences. Such techniques are important to discuss because the significant differences exist in writing and presentation styles between Japanese and American engineers. The author believes that such style differences are caused by differences between the Japanese and American cultures. The objective of this paper is to help Japanese engineers understand these cultural differences and improve their technical communication skills in English. The paper also includes some practical tips on writing and presentation techniques for improving the quality of their technical communications in English.
Parallel redundant operation system using multiple power supply modules is suitable and acceptable for power supply system used in high reliability system. Three types of power supply modules have been developed: single-phase 100V 2kVA module, single-phase 200V 3kVA module, and three-phase 200V 2.5kVA module. Any desired number of these modules can be connected in parallel and are capable of redundant operation. Using these modules makes it possible to economically configure high-performance, high-reliability UPS (Uninterruptible Power Supply) capable of parallel redundant operation.
Recently, the generating electricity used clean energy source attracts attention and variousresearch have been investigated. Electric power is taken out effectively in the photovoltaic power generator, and it is research on the control of inverter to use it as an a. c power source. The inverter is controlled by MPPT control when it applied to the resistance as the load. The voltage amplification circuit is necessary in order to compose this system and the experiment result, is presented in this paper.
Power flow control methods between a flywheel battery and a load have been studied. In the most case, single load is assumed for single flywheel battery. A power flow method from several flywheel batteries to several loads or flywheels is required to apply the flywheel batteries to the future power distribution systems. In this paper, we propose a power flow control method from several battery-side flywheels to several loadside flywheels simultaneously. All the flywheels are connected to a DC bus whose voltage is VN. The battery flywheels provide the power to the DC bus to keep VN constant. The load flywheels are accelerated according to a reference value of the rotating speed. Hence, the power is provided from the battery flywheels to the load flywheels through the DC bus. Two simulation results illustrate the effectiveness of the method.
This paper presents a newly developed maximum power point tracking (MPPT) method for photovoltaic system. The characteristics of PV panel are numerically formulated and the MPPT is performed by PI control method using the function-transformation-technique. The numerical PV model-parameters are compensated both by the irradiance and temperature. The irradiance is detected by CdS element located beside the PV panel and the temperature is measured by thermistor pasted on the back of PV panel. The experimental data show that MPPT is performed with no perturbation on PV output power and with fast response characteristic using no-current sensor.
In this paper, a tapped inductor filter assisted high frequency isolated soft-switching phase-shift PWM DC-DC power converter is presented to reduce circulating current and improve the efficiency. The effectiveness of the proposed soft-switching DC-DC power converter is verified in an experiment and compared to the conventional ZVS phase-shift PWM DC-DC power converter and semi-soft-switching phase-shift PWM DC-DC power converter. The 700W-100kHz with 31-42V input side and 100V output side DC-DC converter circuit prototype using the power MOSFETs is built and tested. Compared to the conventional ZVS and semi-ZVS phase-shift PWM DC-DC converters the conversion efficiency of the proposed ZVZCS phase-shift PWM DC-DC converter is significantly improved. The proposed DC-DC converter actual efficiency is measured as 93-97% over the wide output voltage regulation ranges and load variations.
The immittance converter is the combined word for the impedance-admittance converter. The immittance converter has an input impedance that is proportional to the admittance of the load connected across output terminals. In this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant voltage source into a constant current source and a constant current source into a constant voltage source. It is well known that the quarter-wavelength transmission line shows immittance conversion characteristics. However, it has very long line length for the switching frequency, and is not suitable for power electronics applications. So we proposed immittance converters that consist of lumped L, C and shows improved immittance conversion characteristics at a resonant frequency. An immittance converter operates at the resonant frequency and is suitable to be inserted into high-frequency link of a power electronics system. Applications of the immittance converter are a utility interactive inverter for photovoltaic system and a non-contact energy transfer system etc. A constant-current DC power supply is proposed in this paper. It can be simply realized by using a high frequency voltage source, an immittance converter and a rectifier. In this paper, circuit operation, characteristic equations and results of simulation with a sinusoidal voltage input are described.
The high-frequency isolated power supply with low-voltage large-current output and widely fluctuating input voltage is discussed in this paper. It is described that it is difficult to achieve high efficiency of the power supply with ZVS phase-shift PWM controlled DC-DC power converter mainly due to high conduction power losses in the rectifier stage. The 2-stage DC-DC converter system configuration, which consists of boost ZVS-PWM DC-DC chopper and ZVS full-bridge high-frequency isolated DC-DC converter operating with maximum duty cycle, is presented. An ability to improve efficiency of the power conversion by using 2 stages DC-DC circuit configuration is discussed. 900W-100kHz DC-DC conversion system prototypes were built and tested. An efficiency comparison between full-bridge ZVS phase-shift PWM DC-DC power converter and 2-stage soft-switching DC-DC converter has been made. It is proved that using 2-stage DC-DC converter can improve efficiency under full load.
We have been improving the long distance and precise measurement of the stereo measurement. Concretely, our method uses multiple cameras to reduce the influence of quantization errors on the stereo measurement. In this paper, computer simulations and experiments are shown to verify the possibility of the practical application of our method practical. We intend to realize the new type image sensor that can measure the position of the target in the accuracy over the double from the convention method.