宮武 昌史

Recently, a new generation of ac-ac single-phase and three-phase power converters with more commutations per half cycle has been proposed for ac power or ac voltage conditioning due to the increasing availability and power capability of high frequency controlled-on and off power semiconductor switching devices. This paper presents a novel simple circuit topology of symmetrical PWM ac line conditioning circuit for three phase power systems. The converter topology uses a minimal number of controlled power semiconductor switches and features buck voltage capability. This ac-ac power converter is seen to be an ac voltage regulator with output voltage range of 0-1 p.u. with reasonable current and voltage waveforms. The operating principle and the operation modes of the proposed three-phase direct ac-ac power and voltage conditioner are described and evaluated through a design example based on analytical expression and simulation results.

This paper presents an advanced one-stage power conditioner circuit configuration suitable and acceptable for new energy generation systems specially low voltage large current distributed power supplies as solar photovoltaic and fuel cell or new storage applications as electric double layer capacitors and new type batteries. The circuit configuration depends mainly on eliminating the unreliable electrolytic capacitor DC link and using a bypass diode and coupled inductor assisted boost chopper to increase the boosting ratio and achieving high power conversion efficiency. This power conversion system is a modified version of the DC-DC converter previously proposed by the authors, which is composed of a time-sharing operated sinewave absolute modulated bypass diode and coupled inductor assisted boost chopper to produce a sinewave absolute value tracking AC voltage at the DC link and a sinewave PWM cascaded inverter to produce the sinusoidal AC voltage. This power conditioner is operated by selective time-sharing dual mode pulse pattern signal processing control scheme. The paper discusses also the soft switching operation of the coupled inductor boost chopper using only a passive auxiliary edge-resonant snubber circuit for further improvement in the total power conversion efficiency. The operating principle and the unique features of this new power conditioner are described and evaluated through a design example based on simulation results.

An algorithm optimizing total energy consumption of multiple train operation considering a DC feeding circuit is investigated in this paper. Our mathematical formulation includes several characteristics of trains which depend on feeding voltage. It makes it possible to give detailed consideration to an energy-saving operation. It is especially important for us to be able to discuss the influence of squeezing control of regenerating current and feeding loss. We constructed the optimizing algorithm based on the gradient method applicable to large-scale problems for future works. Several numerical examples are demonstrated to verify the reliability and validity of the proposed method. Every optimisation result is obtained within a minute.

This paper proposes a hybrid energy system combing solar photovoltaic and wind turbine as a small-scale alternative source of electrical energy where conventional generation is not practical. A simple and cost effective control technique has been proposed for maximum power point tracking from the photovoltaic array and wind turbine under varying climatic conditions without measuring the irradiance of the photovoltaic or the wind speed. The proposed system is attractive owing to its simplicity, ease of control and low cost. A complete description of the proposed hybrid system along with detailed simulation results which ascertain its feasibility are given to demonstrate the availability of the proposed system in this paper. Simulation of the hybrid system under investigation was carried out using PSIM software.

The optimal train operation which minimizes sum of supplied energy from substations is presented in this paper. In recent years, the energy storage devices have enough energy and power density to use in trains as on-board energy storage. The electric double layer capacitor (EDLC) is assumed as an energy storage device in our study, because of its high power density. The on-board storage can assist the acceleration/deceleration of the train and may decrease energy consumption. Many works on the application of the energy storage devices to trains were reported, however, they did not deal enough with the optimality of the control of the devices. On the other hand, our previous works were to optimize acceleration/deceleration commands of the train for minimizing energy consumption without the energy storage device. Therefore, we intend to optimize acceleration/deceleration commands together with current commands through energy storage devices as our next research target. The proposed method can determine the optimal acceleration/deceleration and current commands at every sampling point. For this purpose, the optimal control problem of the train operation is formulated mathematically. It is generally difficult to solve the problem because the problem is composed of a large-scale non-linear system. However, the Sequential Quadratic Programming (SQP) can be applied to solve the problem. Two results with and without on-board energy storage device are compared. These optimized results indicate that the total energy consumption is reduced by at least 0.35% by using the EDLC. The relation between internal resistance and energy consumption is also revealed.

This paper presents a novel circuit topology of isolated DC-DC power converter, which includes stable and efficient zero voltage soft switching (ZVS) full bridge inverter in the high frequency planer transformer primary-side and zero current soft switching rectifier in its secondary side. This power converter incorporates zero current soft switching (ZCS) phase-shifted PWM controlled two active power switches in series with either right or left leg of full-bridge of a transformer secondary-side. The proposed soft switching DC-DC power converter can achieve a wide soft-switching commutation under wide load variations from an extremely light load to a heavy load at a condition of a constant frequency phase-shifted PWM voltage regulation and high efficiency voltage regulation due to reduced circulating current in the primary side of the transformer. Its operating principle in steady state is described and its performances are evaluated and discussed based on simulation analysis and experimental results obtained on a 2 k W and 40 kHz breadboard power converter setup. The practical effectiveness of this soft-switching DC-DC power converter with a high frequency link is proven on the basis of simulation and experimental results. © 2005 IEEE.

This paper presents a novel boost-full bridge cascade system topology without electrolytic capacitor DC filter link and its time-sharing control scheme of a selective dual mode pulse modulated high efficiency single-phase sinewave power conversion conditioner for small scale new energy generation applications. This power conversion system is composed of a sinewave absolute value tracking boost chopper with a bypass diode in the first power stage and sinewave PWM full-bridge inverter in the second power stage operated by dual mode selective time-sharing pulse pattern signal processing control approach. The unique operating principle of two power conditioning and processing stages with sectional time-sharing dual mode partial sinewave modulation scheme is described and discussed for stand alone utilization. The paper proposes a sinewave tracking voltage controlled soft switching PWM boost chopper with a bypass diode loop, which includes a passive auxiliary edge-resonant snubber. The new conceptual operating principle of this novel sinewave pulse modulated power conditioner acceptable for small scale new energy generation is evaluated through the experimental and simulation results, together with a control implementation. © 2005 IEEE.

The paper presents a novel circuit topology of a high efficiency single-phase sinewave power conditioning and processing converter with a DC-link chemical capacitor. This power conditioner, used as a small scale stand-alone new-energy related power generation system, is composed of time-sharing operated sinewave absolute modulation boost chopper with a bypass diode in the first power processing stage and cascaded with a time-sharing sinewave pulse modulated full-bridge inverter as a second power processing stage operated by time-sharing dual mode pulse pattern control scheme. The unique operating principle of the power processing stage with the time-sharing dual mode sinewave modulation scheme is described with a simple design example. The paper provides and describes also a sinewave tracking voltage controlled soft switching PWM boost chopper with a passive auxiliary edge-resonant snubber. The new conceptual operating principle and the effectiveness of this novel one stage sinewave power conditioner related to new-energy generation system is reviewed through the experimental results.

This paper is aimed at presenting a novel system topology and control scheme of a selective dual mode pulse modulated high efficiency single-phase sinewave power conversion circuit for new energy generation and storage applications. This power conversion system is composed of a time-sharing operated sinewave absolute modulation boost chopper with a bypass diode in the first power conditioning and processing stage and time-sharing sinewave partially pulse modulated full-bridge inverter in the second stage. The proposed power conditioner is operated by selective time-sharing dual mode pulse pattern signal processing control scheme without electrolytic capacitor DC link. The unique operating principle of the two-power conditioning and processing stages with sectional time-sharing dual mode partial sinewave modulation scheme is described and discussed with a design example. In addition, the paper proposes also a sinewave tracking voltage controlled soft switching PWM boost chopper with a bypass diode loop, which includes a passive auxiliary edge-resonant snubber. The new conceptual operating principle and the control implementation of this novel power conditioner are presented and evaluated through experimental and simulation results.

This paper deals with Maximum Power Point Tracking control of photovoltaic generators. Photovoltaic generation systems need Maximum Power Point Tracker (MPPT) because the output power depends on the operating voltage and current. The authors have proposed the MPPT employing line search algorithm with fibonacci sequence. Finding maximum power point is difficult when a photovoltaic array is partially shaded, because two or more maximum power points may appear. In this paper, the authors improve the proposed method in order to find the global maximum under the partially shaded condition. The improved algorithm has good performance in many experiments. In addition, the authors also mention that the compensation of the large output fluctuation caused by the proposed MPPT by using a wind turbine generator as a kind of flywheel energy storage.

An algorithm optimizing the train running profile with Bellman's Dynamic programming (DP) is investigated in this paper. An optimal train running trajectory which minimizes amount of total consumed energy has been produced under fixed origin and destination, stipulated running time, limited electric motive force and electric brake by VVVF controlled induction motor/generator blended with mechanical brake, several local speed constraints and local inclines. Many previous works on this area adopt the numerical techniques of calculus of variations, Pontryagin's maximum principle, incremental method, and so on. But these methods often meet some difficulties accounting for complicated actual train running preconditions, e.g. complicated functions which describe electrical motive/brake torque, local constraints of state variables as speed limits, nonlinear running resistance and variable grade profile. DP can cope with such complicated conditions. It can directly deal with such difficult constraints of an optimal control problem, except for terminal boundary condition. In a DP process of a former research, the position and velocity of train and total running time were divided into nonuniform lattice and the numerical algorithm solved state equations partially and calculated interpolated local valuation. The authors have made the improvements for reducing the calculation time of the optimization process and improving the accuracy of the solution. An optimal run-curve can be obtained in a practically acceptable computational time even when it is applied to actual complicated running conditions. The required error of distance and speed at destination is less than 0.6m and 0.1m/sec respectively. The authors have concluded that the small error guarantees the reliability of the results.

This paper examines the implications of changing of operating mode or duration of contract of independent power producers in power sector planning in Indonesia. In particular, an approach is developed to assess the contributions of supply- and demand-side effects to the changes in CO2, SO2and NOxemissions from the power sector due to changing of operating mode or duration of contract of independent power producers. The results show that the supply side effect would increase the CO2, SO2and NOxmitigations, however, the demand side effect would act in the opposite direction. The results also show that the CO2, SO2and NOxemission mitigations would increase if the operating mode or duration of contract is increased from 60 to 80% or from 5 to 15 years respectively. © 2003, The Institute of Electrical Engineers of Japan. All rights reserved.

In this paper, an input-output decomposition model has been developed to examine the factors which affect the economy-wide CO2 emission changes due to considering independent power producers (IPPs) in the Indonesian power sector during 2003-2017. There are four major components that affect the total economy-wide change in CO2 emissions, i.e., fuel mix-, structural-, final demand-and joint-effects. The results show that considering IPPs in power sector planning in Indonesia would mitigate the CO2 emissions. The CO2 mitigations would increase if the length of contract between IPPs and the existing utility is increased. The CO2 mitigations would increase 2.1 times higher if the duration of contract is increased from 5 to 15 years. Of the total CO2 mitigations, the fuel mix- and structural-effects would increase the CO2 mitigations, however, the final demand- and joint-effect would act in the opposite direction under all duration of contract cases.

This paper examines the factors which affect the CO2 emission changes in the economy as a whole due to considering independent power producers (IPPs) in the Indonesian power sector during 2003-2017 by using an input-output decomposition model. From the development of the decomposition model, it is found that there are four major components that affect the total economy-wide change in CO2 emissions, i.e., fuel mix-, structural-, final demand- and joint-effects. The results show that if the minimum operating mode of IPPs is increased from 60 to 80%, the CO2 mitigations would increase from 40 to 84 million tons during the planning horizon. Of the total CO2 mitigations, the fuel mix- and structural-effects would increase the CO2 mitigations, however, the final demand-and joint-effect would act in the opposite direction under all minimum operating mode cases.

For the electronic equipment, various printed circuit boards are used. Recently, the electronic equipment is getting miniaturized, and insulation reliability of the printed circuit boards becomes the important problem. In this environment, paper phenol base printed circuit boards are produced a lot and mainly used for the consumer article, so that we examined the ionic-migration of paper phenol base printed circuit boards. Generally, the resistance value of the paper phenol base printed circuit board is lowered with continual rapid-dropping and recovering of the resistance value in the high-humidity/temperature test for ionic-migration when it passed about 1500 hours. However, when it passed after 300 hours, the rapid changes of the resistance value by the ionic-migration were observed in our test, and it was observed that the bridging is done between some electrodes of the printed circuit boards.

By development of high power sophisticated semiconductor devices, the voltage source type self-commutated converter has been introduced to DC transmission systems. The transformer connecting it to the AC system can be eliminated with its elaborate current control ability The control scheme of normal operations and fault conditions in DC transmission system that transformers have been removed, is considered. The performances of the system are studied with simulation using PSCAD/EMTDC. It is shown that it can regulate power flow faster in normal condition and suppress overcurrent under faults better, comparing with the system installing transformers.

The control scheme and characteristics of the unified power flow controller (UPFC) installed at the substation connecting the transmission system with the distribution network, are studied in relation with the power quality improvements for the loads. A simplified model of UPFC with network is introduced on the basis of the instantaneous power and reactive power function to design the control system and evaluate the effect to improve power quality in the load system. The effectiveness of UPFC is concluded for the power quality control in the substation connected to the distribution network both for the voltage dip and harmonics distortion. It would function with the same principle to suppress the interaction between the distant high power supply and the distributed small power generator in the load network.

This paper describes the control scheme and characteristics of the UPFC (Unified Power Flow Controller)installed at a substation near the end of customer side, which works to improve the power quality at demand side by power conditionings. in this study simulation has based on the function of the instantaneous power and reactive power under the condition that UPFC has been installed near the demand side. The effectiveness of it is concluded as a result of voltage dip suppression and removal of harmonics distortion. UPFC, also, would be able to suppress the interaction between the high power supply from power plants and power generation on a small scale by consumers, and remove any harmonics distortions injected from other loads or power system networks.

Vertical transportation of large capacity is essential for high-rise buildings. Limitation of the handling capacity is due to the fact that only one car can be operated per shaft in conventional roped lift systems. Therefore, ropeless direct drive technique for lifts is a key technology. In the, ropeless lift systems, the operation of several cars in one shaft and transferability between shafts can be realized. It is important to operate cars taking these merits of ropeless lift systems into account. The authors, therefore, propose a scheduling method of multiple cars for long vertical transportation. In these systems, an operating technique for railway systems has given a basis of the scheduling. Based on the scheduling, the authors analyse potential capability of ropeless lift systems, compare these results with those of conventional roped lifts, and have verified substantial advantages of the proposed ropeless lift systems in handling capacity.