Acta Medica Okayama 13 2 1998 The state-of-the-art of power electronics in Japan 345 356 EN Hirofumi Akagi <p>Since the late 1950s, power electronics has been developing by leaps and bounds without saturation to become the key technology essential to modern society and human life as well as to electrical engineering. This paper mainly focuses on the state-of-the-art of power electronics technology and its medium to high-power applications because the author cannot survey the whole spectrum of power electronics ranging from a 5 W switching regulator to a 2.8 GW high-voltage DC transmission system now under construction in Japan. This paper also presents prospects and directions of power electronics in the 21st Century, including the personal views and expectations of the author</p> No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 13 2 1998 The unified power quality conditioner: the integration of series and shunt-active filters 315 322 EN Hideaki Fujita Hirofumi Akagi <p>This paper deals with unified power quality conditioners (UPQCs), which aim at the integration of series-active and shunt-active power filters. The main purpose of a UPQC is to compensate for voltage flicker/imbalance, reactive power, negative-sequence current and harmonics. In other words, the UPQC has the capability of improving power quality at the point of installation on power distribution systems or industrial power systems. This paper discusses the control strategy of the UPQC, with a focus on the how of instantaneous active and reactive powers inside the UPQC. Experimental results obtained from a laboratory model of 20 kVA, along with a theoretical analysis, are shown to verify the viability and effectiveness of the UPQC </p> No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 13 2 1998 The unified power quality conditioner: the integration of series and shunt-active filters 315 322 EN Hideaki Fujita Hirofumi Akagi <p>This paper deals with unified power quality conditioners (UPQCs), which aim at the integration of series-active and shunt-active power filters. The main purpose of a UPQC is to compensate for voltage flicker/imbalance, reactive power, negative-sequence current and harmonics. In other words, the UPQC has the capability of improving power quality at the point of installation on power distribution systems or industrial power systems. This paper discusses the control strategy of the UPQC, with a focus on the how of instantaneous active and reactive powers inside the UPQC. Experimental results obtained from a laboratory model of 20 kVA, along with a theoretical analysis, are shown to verify the viability and effectiveness of the UPQC </p> No potential conflict of interest relevant to this article was reported.