Toshikazu Horiuchi

Feasible performance evaluations of active resonant snubber-assisted three phase soft switching inverter

This paper presents an active resonant snubber-assisted three phase voltage source type soft switching inverter with space voltage vector modulation scheme which can operate under the principle of zero voltage switching (ZVS) condition. The steady-state performances of this digitally-controlled soft switching inverter which is suitable for high-power applications is illustrated and evaluated as compared with a hard switching inverter on the basis of experimental results.

Auxiliary active quasi-resonant commutation block snubber-assisted voltage source three phase soft switching PFC rectifier

This paper presents a new active quasi-resonant snubber-assisted (auxiliary quasi-resonant commutation block-link; ARCB) voltage source type three phase soft switching PWM-PFC rectifier, which can operate under a principle of zero voltage soft switching (ZVS) commutation. Its operating principle and the steady-state performances of this digitally-controlled three phase soft switching PWM-PFC rectifier system with an instantaneous power feedback scheme are illustrated and evaluated on the basis of computer-aided simulation analysis.

Utility-interactive three-phase soft-switching pulse width modulated converter with active resonant snubbers in bridge leg sides for energy storage devices

In this paper, a prototype of a multi-functional controlled three-phase voltage-source bidirectional zero voltage soft-switching PWM converter with three auxiliary active resonant commutated snubber link (ARCS) is presented for battery and/or electric double layer capacitor energy storage system (BESS). The operating principle of this active resonant snubber-assisted soft-switching converter circuit for BESS and multi-functional digital control-based converter system including active rectifier and inverter operation modes are described. Operation characteristics of this bidirectional three phase soft-switching space voltage vector modulated converter with ARCS for BESS is demonstrated under the conditions of battery discharging-based peak-cut mode and battery charging-based energy storage mode in with conventional utility three phase hard-switching converter for BESS. The effectiveness of the converter system is proved on the basis of simulation analysis.

Long-term reliability evaluation of power semiconductor devices used in substation rectifiers

To enable evaluation of the long-term reliability of power semiconductor devices used in commercial substations, this paper presents the failure rate of such devices in practical use. Recovery activation energies are also evaluated on the basis of annealing and bias stress test. Degraded devices are disassembled and examined. In some of them, melting and defects at the silicon chip edge caused a large leakage current. It is also found that the leakage current spectrum is strongly related to breakdown voltage degradation. A novel monitoring method using the leakage current spectrum is proposed here for the first time.

Long-term Reliability Evaluation of Power Semiconductor Devices used in Power Station Rectifiers and Substation Rectifiers

In power stations and substations of electric power companies, power semiconductor devices such as diodes and thyristors have been used in control power supplies and emergency power supplies since the 1970s. Such equipments designed on the assumption that power semiconductor devices are semipermanent, since their service life is much longer than those of capacitors and resistors. Therefore, it is hard to find studies that systematically examine the long-term reliability of semiconductor devices.Such studies are very important from the viewpoint of assuring reliability and of improving the renewal period by proper equipment maintenance. This paper presents the long-term reliability of power semiconductor devices used in power station rectifiers and substation rectifiers.

Novel monitoring method and long-term reliabitity evaluation of power semiconductor devices in power utilities

In this paper, the relationship between failure rates of power semiconductor devices and their operation period is investigated to assure reliability and improve the renewal period of such equipment. And a novel monitoring method using a leakage current vector is proposed, and its superiority is estimated for the first time.

Three-phase voltage source soft-switching inverter for battery and super capacitor energy storage plants

In this paper, a prototype of a multifunctional bidirectional three-phase voltage-source zero voltage soft-switching converter with a single resonant DC busline linked snubber (RDCS) or three bridge arm linked auxiliary active resonant commutation snubbers (ARCS) is presented for battery and/or electric double layer capacitor energy storage systems (BESS). The operating principle of the active resonant snubber-assisted soft-switching converter circuit and digitally controlled multifunctional converter system including active rectifier and inverter operation modes are described and evaluated herein for BESS. The effectiveness of the soft-switching bidirectional converter system is proved on the basis of simulation analysis.