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This paper analyzes the regenerative elevator operation and energy savings of the faculty elevator. The study is based on measurements taken during a week of high travel demand. The results are compared to previous weekly measurements taken with the same elevator during lower travel demand. The effects of travel demand on regenerative potential and energy efficiency are analyzed. Energy savings are calculated using two different approaches and the impact of standby energy is highlighted. In addition, the energy efficiency, total annual energy consumption and annual energy savings are calculated according to the energy efficiency classification standards VDI 4707 and ISO 25745 and compared with the results of measurements performed at low and high travel demand. The regenerative cycles are studied in detail to determine the requirements for a future energy storage system. The results have shown that increased travel demand increases the energy efficiency of the elevator system. This effect is not obvious when considering only the results obtained according to the elevator energy efficiency classification standards. Moreover, the overall energy efficiency of the elevator system can be further improved by reducing the energy consumption in standby mode.

Energy and environment are the supreme priority of the 21st century. Proliferating use of Electric vehicles introducing zero pollution transport system. Electric bikes are widely attractive due to the affordability and compact size. Paper provides basic design analysis of electric bikes. The research analyzed and compute the power requirement, battery capacity, maximum angular velocity, converter parameters and filter values for the required electric bike. Simulation and calculation analysis are performed for both driving and regenerative mode using a bidirectional converter. The research concludes the power consumption, regenerative energy, charging current behavior while driving and the impact of regenerative braking on mileage. Results also provide a comparison of electric bikes with ICE bikes.

Our research group is developing an electric orthosis for assisting hemiplegic patients to walk. Lack of electrical power is a problem for this orthosis, so, as an improvement to this device, we are developing a generator that generates power efficiently from the rotation of joints while the patient walks. In this report, the outline and the improvement of the controller circuit are described. The circuit connects two boost chopper circuits in parallel. By shifting one of the switching phases of their circuits by 180°, the battery voltage output can be increased to 17% more than that of a conventional circuit.

This paper presents a novel theory to evaluate the use of regenerative energy in traction systems by introducing the concept of regenerative compensation factor, which can be seen as analogous to the concepts of reactive energy and power factor in AC power systems. The proposed theory is applied to a regenerative energy case study in Metro de Medellin, using computational tools (OpenTrack and OpenPowerNet), and field measurements of the operation of two regenerative compensation prototypes. The results show that the proposed compensation factor provides technical guidelines on regenerative energy management, and is useful to identify potential energy savings, to determine a better use of installed railway facilities, and to propose improvements in conception, design and operation of an electric traction system.

A 48V active clamp resonant single-ended primary inductor (SEPIC) converter has advantages, which are switch voltage stress suppression and achieving zero-voltage switching (ZVS). Therefore, it is effective in renewable energy systems that can provide a 48V dc bus. This paper clarifies how the active clamp resonant SEPIC converter is affected by whether the active clamp circuit is connected to the input or output side and its performance mechanism is clarified.

Regenerative energy utilization is one of the most actively discussed topics to improve the efficiency of power supply system for DC electric railway. We, East Japan Railway Company, have already installed four energy storage systems and two regenerative inverters for regenerative energy utilization. In the regenerative energy utilization, the utilization of regenerative energy which is originally utilized by other powering train dose not contribute to energy saving and the appropriate evaluation of the effect of such devices is required. In this paper, a novel concept of “valuable interception” of regenerative energy is proposed and evaluated supposing one of the existing commuting DC railway line in Tokyo. As a result, it is shown that the interception of regenerative power can contribute to the reduction of loss under some conditions.

East Japan Railway Company (hereinafter referred to as JR-EAST) have introduced energy storage systems (hereinafter referred to as ESS) and regenerative inverters to reduce electric energy by effectively utilizing regenerative energy generated at the time of braking by the rolling stocks. The regenerative inverter at Fukiage Substation (hereinafter referred to as SS) on Takasaki Line started to use in 2018. It is important to verify the energy saving effect of the regenerative inverter in order to make plans to introduce the equipment in the future. However, little study has been done to evaluate energy saving effect of regenerative inverter in detail. Therefore, the energy saving effect of the regenerative inverter at Fukiage SS on Takasaki Line was analyzed, and the authors report the result.

Our research group designed and made two trial production for two electric buses, a small-sized bus for driving on ordinary roads and a medium-sized bus for driving on expressways. Approximately one-year verification test was conducted in the Metropolitan Expressway Bay Shore route and surrounding areas in Japan. In this paper, analyzed results focused on the regenerative energy while traveling on expressways compared to ordinary roads made by heavy-duty electric vehicles will be summarized.

Maximizing regenerative energy utilization (REU) through timetable optimization has become a hot topic recently. Considering the constraints of operation time for a subway system and travel time for each train, we propose a new timetable optimization problem to maximize REU. We formulate its mathematical model, and then an artificial bee colony (ABC)- based algorithm is designed to solve it. Case studies are conducted based on the actual data obtained from a real subway line. Experiments results prove the correctness of the mathematical model and effectiveness of the proposed ABC-based algorithm. The results are also used to improve the currently used timetable by reallocating its headway and dwell time properly. Impacts of decision variables on REU are discussed, which is useful for the timetable designers. In addition, the ABC-based algorithm is compared with GA and outperforms the latter.

With the increasing application of railway transportation, energy consumption of railway transportation rises dramatically, which in turn undermines its sustainability. Optimization on train speed profile and use of regenerative energy is becoming a feasible and applicable approach to achieve an energy-efficient operation without changing existing infrastructures. Considering both dwelling at stations and running in the inter-station sections, the paper proposes an integrated optimization model for reducing net energy consumption from the viewpoint of energy interaction among train, substation and on-board energy storage device (ESD), based on which the optimal train speed profile is also found. The discharge/charge strategy of on-board ESD is explored and comparative case studies are given, under the assumption of higher efficiency from the on-board ESD, less net energy consumption can be achieved via energy interaction with substation. Through charging from substation the net energy consumption can be reduced, i.e. 0.2%, in the comparison.

From the viewpoint of energy saving, the optimal control method of stationary energy storage systems is a method of minimizing of the total energy supplied from all the related traction substations. The purpose of this paper is to find the optimal charging/discharging power control method of the energy storage system under the condition in which speed profiles and driving operations of all trains are fixed. We make some assumptions to model this problem as a mathematical optimization problem. In this paper, we introduce some calculation results obtained by varying parameters. We also indicated that this mathematical optimization model can calculate the maximum effect on energy saving which is useful to design the energy storage system. In addition, we confirm the validity of this mathematical optimization model and estimate the effects of the energy storage system on energy saving.

This paper aims at determining the influential factors affecting regenerative braking energy in DC rail transit systems. This has been achieved by quantitatively evaluating the dependence of regenerative energy on various parameters, such as vehicle dynamics, train scheduling, ground inclination and efficiency of the electrical devices. The recuperated power and energy have been presented by a mathematical model, comprising of a set of empirical forms, which allows for thorough analysis. A detailed simulation model of a typical DC-traction system has been developed to validate the developed empirical forms. The results verified the validity of the proposed mathematical model, and demonstrated the significance of the examined parameters on the regenerative power and energy of a train during a complete cycle. Knowledge of the parameters impacting the magnitude of regenerative energy should maximize the potential of harnessing regenerative energy.

In 2006, the first Li-ion battery was installed in traction power supply system by West Japan Railway Company and now more than 20 energy storage systems have already installed in traction power supply system in Japan. In this article, the recent trend for regenerative energy utilization is summarized not only in d.c. railway but also a.c. railway. We, East Japan Railway Company, have installed 3 energy storage systems for d.c. railway and one railway static power conditioner for a.c. railway for regenerative energy utilization. The effects of these systems are also shown quantitatively in this paper.

Stationary Energy Storage System (SESS) using Lithium ion (Li-ion) batteries have been in operation in Japan and abroad for the purpose of introducing against regeneration canceled and compensation for a voltage drop, energy saving. This report is made on the effect of energy saving of the SESS based on a case of the introduction of the SESS in Horinouchi Substation of Keio Corporation out of the SESSs Hitachi has supplied in the past.

Recent research has shown great potential in energy efficiency optimization by harvesting regenerative energy of industrial robots. This paper presents further insight into how dependent regenerative energy is on the mass of the robot tool, as well as how the total regenerative energy is distributed between various robot links.

We, East Japan Railway Company, have already installed three energy storage systems in d.c. railway power supply system around Tokyo area for regenerative energy utilization and are now constructing new regenerative inverter system at Tokyo Station. In this paper, advantages and disadvantages of those systems will be compared. Furthermore, the examples of load waveforms of traction power supply system and distribution line system at Kajibashi Substation will be shown to discuss feasibility of regenerative energy utilization.

This paper discusses the control strategy for energy management in railway transit network with wayside (substation) supercapacitor (SC) energy storage system (ESS). Firstly, the structure of the wayside energy storage system is introduced. Secondly, the model of energy storage system is built and the control strategy is described. Thirdly, in order to estimate the required energy storage system, a useful method is proposed to predict the instantaneous regenerative energy magnitude which is delivered to each substation. Finally, the ESS configuration for each substation is determined. A simplified mathematical model of the whole metro network is established and the main features of the control strategy are developed. Numerical simulations show the efficacy of suggested control strategy and the energy saving obtained for railway transit network.

To make railway transportation more efficient, utilization of recuperation energy in d.c. traction power supply system is actively discussed in Japan. We, East Japan Railway Company, have already introduced two Lithium ion battery systems at Haijima Substation since 2013 and at Okegawa Substation since 2014. They contribute to reduce total traction energy supply about 5–8%. In a.c. traction power supply system, on the other hand, it is rarely discussed to make use of recuperation power because it is not an issue compared with d.c. traction power supply system in many cases. We installed, however, RPC, railway static power conditioner, at Ushiku sectioning post for recuperation energy utilization in 2014. In this paper, the difference between d.c. traction power supply system and a.c. traction power supply system from the point of view to utilize recuperation energy and its future prospect in a.c. traction power supply system are discussed.

One of the initiatives toward traction energy saving on the railways is effective utilization of the regenerative energy. Greater efficiency in energy use is achieved through the installation of the energy storage system by discharging the energy depending on the load situation. The energy storage systems are usually used flywheel, nickel-metal hydride batteries, lithium-ion batteries, electric double layer capacitor (EDLC), etc. East Japan Railway Company also installed two energy storage devices using lithium-ion batteries at Haijima and Okegawa substations. This paper describes the installed results of these energy storage systems. Furthermore, the installation effect was estimated using two methods at Okegawa substation.

This paper deals with a control strategy of an active power filter module (APFM) which functions energy-saving by reusing regeneration energy of a traction motor for the lift load. The APFM can be used by additionally connecting dc-link of a usual inverter for motor of the lift load. In motoring mode, the deadbeat current control for APF function is used to mitigate delay factors depending upon data volume and interrupt processing of DSP associated with sampling time. The proposed method determines the operation mode and performs the control algorithm corresponding to each mode. The simulation is implemented to verify the proposed control method for APFM.

To reduce the environmental impact of the DC power system of the East Japan Railway Company (JR-EAST), it is important to have effective regenerative energy transfer from one train to another. In this paper, simultaneous measurements between the Yamanote Line Series E231 trains and the adjacent substations were conducted. From these measurements, the correlation between squeezing control of regenerative power in the trains and behavior of the substations was confirmed. Also, to consider minimizing the total squeezing control of regenerative power and maximizing the regenerative ratio, we studied the total of squeezing control of regenerative power and regenerative ratio on the trains from the data at the substations.

Two Lithium ion battery systems have already installed at practical traction substations, HAIJIMA SS and OKEGAWA SS, to utilize regenerative energy in d.c. 1.5kV traction power supply system of East Japan Railway Company. In this paper, the effect of energy storage system for energy saving by making use of regenerative energy is evaluated in detail. According to our experiences, the annual effects of energy storage systems at HAIJIMA SS and OKEGAWA SS are 400MWh/year and 600 or 700MWh/year, respectively.

To reduce the environmental impact of the DC power system of the East Japan Railway Company (JR-EAST), it is important to have effective regenerative energy transfer from one train to another. In this paper, a simultaneous measurement between a Yamanote Line Series E231 train and the adjacent substations was conducted. From these measurements, the correlation between squeezing control of regenerative power in the train and behavior of the substations was confirmed. Also, to consider minimizing the total squeezing control of regenerative power we studied the total of squeezing control of regenerative power from the data at the substations.

The goal of this paper is to analyze the performance of regenerative energy storage systems (ESS) in electric vehicles. This article presents a comparison of two different hybrid ESSs and using the Li-ion based conventional battery packs. The hybrid ESSs considered in this study combine Li-ion cells with ultra capacitors and hydraulic systems respectively. The configuration of each of these combinations is presented in this document in detail. Performance of all three ESSs for drive cycles has been compared using the Autonomie software.

As phase one of the CHIC (Clean hydrogen in European cities) project, eight Fuel Cell (FC) hybrid buses on route RV1 have been put in service in central London. One of the next steps is to assess and determine the viability of switching from conventional diesel-technology to fuel cell technology on other bus routes in London. This paper reports on a study where a laboratory sized FC hybrid system modelled on the London hydrogen bus (RV1) is used to explore potential opportunities. Specifically, this paper examines the performance and optimization of a FC hybrid propulsion solution having a smaller FC and various energy storage arrangements. The proposed design is a series hybrid system for the urban driving environment, with focus on transit buses. A Proton Exchange Membrane Fuel Cell (PEMFC) has been selected with a Super Capacitor (SC) as the energy storage technology. The hybrid propulsion system has also been simulated in PSCAD and the model validated using the laboratory sized system. Of particular focus is the control strategy of the hybrid propulsion system to optimise power delivery efficiency during operation and optimise hydrogen consumption. The paper concludes by examining how FC technology can be applied to transit buses with the model validated by experiment and evaluation of the viability of adapting the technology technically. This is a project that is being progressed and this paper will focus on simulation part of the project.

The concept of distributed energy generation in DC-microgrids is becoming more and more popular, due to the enhanced advantages of energy self-supply and minimizing of conversion losses. Based on a sewage application containing a photovoltaic system and a pump application, this paper describes the individual subsystems of a DC-microgrid. A Matlab/Simulink simulation will be presented to view the behaviour of the system with its power flows and potential of optimization. The validation of the simulation model is verified by an experimental setup and the simulation and measured results will be compared.

The ESS has been studied to use regenerative energy all over the world. Recently, In Korea, The DC 1500V ESS was installed and managed in Daejeon Metro line 1 in 2009. This paper presents the control method and tests to upgrade the energy saving rate of the DC 1500V ESS installed in Daejeon Metro line 1. It was installed and managed. And the ESS saved energy, 318,824kwh and reduced CO2, 135.15tons for 10 months. Therefore, the ESS is considered to be one of the useful devices for energy storing and recycling.

In this paper, a system used super capacitor group to recycle the regenerative energy of the heavy gantry portal cranes is briefly introduced, which could save and reuse the energy generated during the download movements of the cargoes and the braking of the trolley, and be more friendly to the environment than the usual portal cranes. What's more the design method of super capacitor group is mainly presented. This method simplifies the calculations, and is easier to define the numbers of the parallel/serial capacitors compared to the usual try and error method.

The concept of regenerative energy management in dual-ac-dc grids in presence of pulse-load is investigated in this paper. The results of this work are applicable to dual ac-dc micro-grids with flywheel (FW) energy storage systems. Undesirable impacts of the pulse-load, on the dual system, are mitigated through both the proposed system configuration, and time-coordination between the occurrence of pulse-loads and the release of kinetic energy from the flywheel. The obtained results are validated through experiments.

A method for the regenerative energy saving in multi-axis servo-motor-drives is presented in this paper. This energy management is achieved through a proper time-coordination between the speed commands of multi-axis drives. Moreover, the proposed approach significantly limits the peak value of the ac input current in these systems. It is mathematically proved that a time-delay can significantly increase the amount of utilized regenerative energy and consequently decreases the amount of dissipated energy. In this paper, a set of closed-form formulas is developed, where the motor losses are neglected. The findings of this investigation were experimentally verified using a two-axis permanent-magnet (PM) motor-drive system, and the results are presented in this paper. The experimental results are in remarkable agreement with the developed closed-form formulas.

If the ESSs are installed on Line 2∼4, we will obtain 16% of energy saving rate and average 4year of ROI. We analyze which substation will be the first order to be installed. The energy saving rate order and the ROI order are different. Even if the energy saving rate is low, because the quantity of regenerative energy is a lot, the ROI is short. Therefore, we have to choose the ROI instead of the energy saving rate to install the ESS. Because the rail operating companies do not have many budget, companies have to install in order from the substation of high energy saving rate to the substation of a little bit high energy saving rate

This paper discusses the main features of two regenerative braking systems, using PWM rectifiers and using an energy storage system connected on the DC bus. Will be presented the features of these systems and simulation results.

The energy storage system in urban transit systems is able to store and discharge energy at an extremely rapid rate. This enables a complete exchange of energy between vehicles, even when they are not braking and accelerating at precisely the same time, as is most frequently case in everyday service. The energy saving rate is related to the headway. If the headway is long/short, the energy saving goes up/down. When the headway is long, the ESS can save a lot of regenerative energy. The headway of SeoulMetro line 2 is very short in Korea urban transit system. So, the energy saving rate will be very low. If the ESSs are applied to another railway system, we expect that the effectiveness is better than the results of SeoulMetro line 2. This paper presents effects of energy saving and reduction of the CO2-emission by applying the ESS to SeoulMetro line 2.

Nowadays the supply of electrical energy from dispersed generation units has an increasing significance. Hence, security related power system operation strategies have to be adapted to face the new situation. In this paper the security of power system operation from the industry and research point of view will be discussed. After presenting an overview about the current situation, the problems will be pointed out. The promising ongoing research topics which have the ability to help the network operators to manage the turn towards a sustainable power system that will allow for exploiting as much regenerative energy as possible by reaching the high standards of security will be described.

In this paper, a regenerative energy conversion system for subway is proposed. In order to simulate the actual voltage and current fluctuation in subway system, The DC line voltage simulator, which is based on PWM AC-DC converter, is developed and implemented. The theoretical explanation is carried out and the validity of the proposed system is verified by simulation and experimental results.

In this paper, a regenerative energy conversion system for subway is proposed. In order to simulate the actual voltage and current fluctuation in subway system, a active simulator, which is based on PWM AC-DC converter, is developed and implemented. Also, the energy storage system is designed using bi-directional DC-DC converter and super capacitors. The theoretical explanation is carried out and the validity of the proposed system is verified by simulation and experimental results.

The mission was to model the electric propulsion and regenerative energy requirements for the Kaikyo passenger train and the Kamolsusen freight train system currently operating between Tappikaitei and Yoshiokakaitei through the Seikan tunnel under the Pacific ocean. The Seikan tunnel is over 54 km in length and connects Aomori on the main Japanese island of Honshu to the North island of Hokkaido. Further, over 24 km of the Seikan tunnel is 100 meters below the sea bed of the Tsugaru Strait which joins the Pacific with the Sea of Japan. While, the sea bed is 140 meters below the mean Pacific sea level, at the deepest point. Safety and energy conservation issues led to reliable regenerative energy recovery and braking systems.

This paper discusses a regenerative braking system (RBS) for a parallel hybrid electric vehicle (PHEV) that performs regenerative energy recovery based on vehicle attributes, thereby providing improved performance, efficiency and reliability at minimal additional cost. A detailed description of the regenerative braking algorithm is presented along with simulation results from a dynamic model of the PHEV exhibiting the regenerative braking performance.