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
en-copyright= kn-copyright= en-aut-name=AkagiHirofumi en-aut-sei=Akagi en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=Okayama University en-keyword=power electronics kn-keyword=power electronics en-keyword=technological forecasting kn-keyword=technological forecasting END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue=2 article-no= start-page=315 end-page=322 dt-received= dt-revised= dt-accepted= dt-pub-year=1998 dt-pub=19983 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The unified power quality conditioner: the integration of series and shunt-active filters en-subtitle= kn-subtitle= en-abstract= kn-abstract=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
en-copyright= kn-copyright= en-aut-name=FujitaHideaki en-aut-sei=Fujita en-aut-mei=Hideaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AkagiHirofumi en-aut-sei=Akagi en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University en-keyword=active filters kn-keyword=active filters en-keyword=distribution networks kn-keyword=distribution networks en-keyword=harmonic distortion kn-keyword=harmonic distortion en-keyword=industrial power systems kn-keyword=industrial power systems en-keyword=power filters kn-keyword=power filters en-keyword=power supply quality kn-keyword=power supply quality en-keyword=power system harmonics kn-keyword=power system harmonics END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue=2 article-no= start-page=315 end-page=322 dt-received= dt-revised= dt-accepted= dt-pub-year=1998 dt-pub=19983 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The unified power quality conditioner: the integration of series and shunt-active filters en-subtitle= kn-subtitle= en-abstract= kn-abstract=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
en-copyright= kn-copyright= en-aut-name=FujitaHideaki en-aut-sei=Fujita en-aut-mei=Hideaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AkagiHirofumi en-aut-sei=Akagi en-aut-mei=Hirofumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University en-keyword=active filters kn-keyword=active filters en-keyword=distribution networks kn-keyword=distribution networks en-keyword=harmonic distortion kn-keyword=harmonic distortion en-keyword=industrial power systems kn-keyword=industrial power systems en-keyword=power kn-keyword=power en-keyword=filters power supply quality kn-keyword=filters power supply quality en-keyword=power system harmonics kn-keyword=power system harmonics END