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In this report, a bidirectional WPT with a single-ended converter is constructed that satisfies the international standard of SAE J2954 for wireless EV charger. The bidirectional converter is consists of a single-ended driven by only one power switching device for practical use. It is realized a system of lightweight, low-cost and compact configurations. Previous system had two problems. One is that the transmission power varies drastically depending on the slight variations of the circuit parameter in single-ended converter. Second is that it is not possible to control the transmission power within the 85kHz band of the international standard. The theoretical analysis reveals that the control factor of transmission power is the phase difference between the power feeding side and power receiving side. A resonant capacitor selector is proposed to solve the low robustness. It is proved in simulation that high robustness is ensured compared to previous system in this control method. A combination control method of resonant capacitor selector and supply voltage changer is proposed to solve the narrow power control range. It is verified in experiment that control range of 0~6kW is ensured under 85kHz band in this control method. Moreover, only home side supply voltage changer is proposed to lower cost. Thus, wireless V2H system with a single-ended converter with a newly developed controller is realized productivity, compatibility and controllability under the international standard.

EV (Electric vehicle) solves the global warming caused by carbon dioxide, because low-loss drive under CO2/NOx free. The wireless battery charger is a promising system because of easy and safe to use for a broad range of users including the elderly. These advantages show that WPT can be the next generation charging system. However, under the case of wireless charging of EVs, there are problems such as deterioration of transfer power or efficiency due to the coil-misalignment. This paper presents a novel position detecting method with a simple configuration that provides the necessary accuracy by using a differential voltage of the auxiliary detection coils.

This research paper focuses on a prototype electric dynamic WPT operated scooter based on electric double layer capacitors (EDLCs) to develop an ecological and extremely effective motorcycle that contributes to solving global warming issues such as the lack of natural energetic reserves. This paper describes a new type of ultra-capacitor electric scooter equipped with a Wireless Power Transfer (WPT) future electricity system. Two transmission coils, a double-D coil (DD coil) and a spiral coil, are also discussed in comparison with each other. In addition, we are proposing the Multi Power Feed Dynamic Wireless Power Transfer System to extend the travel distance. The design process of the system and the fundamental performance test results are also described and considered.

In recent years, expectations for electric vehicles have been increasing as a countermeasure against global warming. A key to their widespread adoption is the development of small-size, lightweight, and low-cost electric vehicle chargers. Electric vehicle chargers with wireless power transfer (WPT) are easier to use, cleaner, and automatically than conventional wired charger. We propose a low-cost WPT apparatus with single-ended inverter based on a new type of V-groove trench SiC-MOSFET(SiC-VMOSFET), with the addition of a Kelvin source to improve gate drive. First, we describe the compact and lightweight WPT apparatus of using a single-ended converter. Second, estimated is a high power WPT apparatus which has a low on-resistance and high breakdown voltage SiC-VMOSFET. Next, we describe the new kelvin-driven SiC device using an improved Kelvin source connection and improvement of circuit pattern to reduce the switching loss.

Although the widespread use of a smart houses leads to the prevention of global warming because they do not emit CO2, batteries which is key device are so expensive that their spread is hindered. A vehicle to home system can reduce cost of the system, electric vehicles support the battery within the system. Wireless vehicle to home systems are able to remove usual vehicle to home power cables, the system will be more convenient and safe. However, wireless vehicle to home systems consist of a conventional bridged inverter using four power switching devices are expensive. Therefore, newly developed has been cost effective, compact and light wireless vehicle to home with a single-ended inverter. The vehicle to home system generally requires 6kW transfer power, which is enough to drive all apparatus of a home. Then a vehicle to home using a single-ended inverter with a synchronous parallel bi-directional control and a bi-fila transmission coils is proposed.

This paper proposes a novel multipurpose operation planning method for minimizing the prediction error of photovoltaic power generator outputs (PV); towards reducing the operating cost and improving voltage stability of power systems. The operation schedule (coordination) of demand response (DR) program and storage system are taken into account as the main parameters for achieving an improved voltage stability and reduction of PV output prediction error. In this approach, the stochastic programming algorithm is introduced for incorporating the uncertainty of PV output and the utility demand response for consumer side management. This is achieved by using the multi-objective genetic algorithm (MOGA) for multipurpose operation plan. The MATLAB optimization toolbox and neural network toolbox were applied in this research study. An IEEE-6 bus system is used to demonstrate the effectiveness of the proposed solution in power systems operation. The approach led to $ 25003.39 ( = $ 99594.53 - $ 74591.14 ) reduction in the system operating cost, compared to the conventional approach. The simulation results also show that by using the proposed algorithm, the capacity of installed PV generators was increased and the voltage stability was improved at the same time. This accounted for the reduction in the effective operating cost and the improved operating condition of the power system.

This paper presents a control approach for the Permanent Magnet Synchronous Generator (PMSG) based Wind Energy Conversion Systems (WECS) under a wide range of wind speeds. Generally, most of the wind turbines are turned-off and disconnected from the power grid, in case wind velocity is gone over 25 m/s. It may cause wind power supply shortage from wind farms. This research introduces a pitch angle controller as well as a rotational speed control system so that the PMSG based WECS can generate power if the wind speeds are above 25 m/s. The proposed method reduces the mechanical stress of the wind turbine by preferential reducing of the rotational speed rather than the mechanical torque during strong wind condition. As a result, the chance of turning-off the is reduced compared to the conventional control system because the PMSG based WECS can temporarily tolerate the wind speed up to 35 m/s. A 2 MW WECS with the electrical and mechanical characteristics is modeled in the MATLAB/SimPowerSystems® to verify the proposed research.

This paper presents a smart house-based power system for thermal unit commitment programme. The proposed power system consists of smart houses, renewable energy plants and conventional thermal units. The transmission constraints are considered for the proposed system. The generated power of the large capacity renewable energy plant leads to the violated transmission constraints in the thermal unit commitment programme, therefore, the transmission constraint should be considered. This paper focuses on the optimal operation of the thermal units incorporated with controllable loads such as Electrical Vehicle and Heat Pump water heater of the smart houses. The proposed method is compared with the power flow in thermal units operation without controllable loads and the optimal operation without the transmission constraints. Simulation results show the validation of the proposed method.

Renewable energy sources (RESs), as clean, abundant, and inexhaustible source of energy, have developed quickly in recent years and played more and more important roles around the world. However, RESs also have some disadvantages, such as the weakness of stability, and by the the estimated increase of utilizing RESs in the near future, researchers began to give more attention to these issues. This paper presents a novel output power fluctuate compensation scheme in the small-scale power system, verifying the effect of output power control using storage battery, demand-response and RESs. Four scenarios are considered in the proposed approach: real-time pricing demand-response employment, RESs output control use and both of demand-response and RESs output control implementation. The performance of the proposed control technique is investigated using the real 10-bus power system model of Okinawa island, Japan. Moreover, the system stability is checked using the pole-zero maps for all of the control loops associated with the proposed scheme. The robustness and effectiveness of the proposed method was verified by simulation using Matlab ® /Simulink ® .

Currently, the Direct-Current (DC) microgrid has been gaining popularity because most electronics devices require a DC power input. A DC microgrid can significantly reduce the AC to DC energy conversion loss. However, a power grid may experience a line fault situation that may damage important household devices and cause a blackout in the power system. This work proposes a new line fault protection scheme for a DC microgrid system by using a battery energy storage system (BESS). Nowadays, the BESS is one of the most cost effective energy storage technologies for power system applications. The proposed system is designed from a distributed wind farm smart grid. A total of three off-shore wind farms provide power to the grid through a high voltage DC (HVDC) transmission line. The DC microgrid was modeled by a BESS with a bi-directional DC&ndash, DC converter, various DC-loads with step down DC&ndash, DC converters, a voltage source converter, and a voltage source inverter. Details of the control strategies of the DC microgrid are described. During the line fault situation, a transient voltage was controlled by a BESS. From the simulation analyses, it is confirmed that the proposed method can supply stable power to the DC grid, which can also ensure protection of several loads of the DC microgrid. The effectiveness of the proposed system is verified by in a MATLAB/SIMULINK&reg, environment.

This paper proposes the load frequency control method using model predictive control for isolated power system without thermal generator. Two control approaches are presented for generation and demand sides to achieve the generation/load balance and hence damp frequency fluctuations. First, five model predictive controllers are designed for wind power generator, photovoltaic generator, storage battery, fuel cell, and seawater electrolyzer to control their output power. Moreover, real-time pricing scheme is utility modify the controllable loads according to the value of frequency error.

Output power fluctuation of the wind turbine generator is a serious issue for power systems. The battery energy storage system is installed to the power system to solve this problem. However, the large battery energy storage system can increase the capital cost of the wind turbine generator system. Hence, the capacity of the battery should be reduced as much as possible. This article presents an H∞ based control method for the output power smoothing method of the wind turbine generator by using a battery energy storage system. The output power fluctuation of the wind turbine generator is considered in the frequency domain. Low-frequency fluctuations are smoothed by pitch angle control of the wind turbine generator, while high-frequency variations are smoothed by charge or discharge of the battery energy storage system, respectively. The battery energy storage system’s capacity and mechanical stress of wind turbine blades can be reduced by the proposed method. In addition, the gain-scheduled contro...

This paper concentrates on the optimal operation of the conventional thermal generators with distributed generations for a smart grid considering forecast error. The distributed generations are considered as wind generators, photovoltaic generators, battery energy storage systems in the supply side and a large number of smart houses in the demand side. A smart house consists of the electric vehicle, heat pump, photovoltaic generator and solar collector. The electric vehicle and heat pump are considered as the controllable loads which can compensate the power for the forecast error of renewable energy sources. As a result, power generation cost of the smart grid can reduce through coordinated with distributed generations and thermal units scheduling process. The electric vehicles of the smart house are considered as the spinning reserve in the scheduling process which lead to lessen the additional operation of thermal units. Finally, obtained results of the proposed system have been compared with the conventional method. The conventional method does not consider the electric vehicle in the smart houses. The acquired results demonstrate that total power generation cost of the smart grid has been reduced by the proposed method considering forecast error. Effectiveness of the proposed method has been verified by the extensive simulation results using MATLAB® software.

This paper focus on a newly developed power electric dynamic WPT(Wireless Power Transfer) driven scooter using Electric double-layer capacitor (EDLC) The new motorcycle is environmentally friendly and highly efficient, and lead the solution of global environmental problems including energy resources shortage. In this paper, a new EDLC electric scooter with WPT next generation power supply system is described. Design flow and experimental results of basic evaluation are explained and discussed.

Recently, the introduction of Renewable Energy Sources (RESs) has been remarkable. However, the RESs are the cause of output power fluctuation which depends upon the weather condition. It also causes system frequency to deviate that means reliability of system is decreased. In particular, RES's output power which varies steeply and significantly is a cause of concern. Due to these output power fluctuations, the supply-demand balance gets worse, in the worst case, massive blackout can occur. In this paper, we propose emergency demand response (EDR) method to prevent the steep output power fluctuation of the RESs. The EDR adjusts the supply-demand balance by changing the consumed power of controllable load depending on system frequency drop. When the system frequency drops steeply, the system frequency is restored rapidly within acceptable range using the EDR.

Due to the depletion of fossil resources and the increase in carbon dioxide emissions, renewable energy systems (RESs) such as photovoltaic (PV) and wind generator (WG) have become an active player in power systems (PSs). In Japan, diesel generators (DGs) are the means of power generation in most isolated islands. Therefore, the introduction of RESs into these islands is of great importance. However, due to the uncertainty of RESs, battery energy storage systems (BESSs), fuel cells (FCs), and exploiting the electric vehicles (EVs) owned by customers are expected as vital power sources for the next generation. Moreover, demand response programs are utilized in this paper. As a result of reforming PSs in recent years, transactions on power markets have also been increasing in Japan. The Japan electric power exchange provides day-ahead market, intraday hour-ahead market, and forward market. It is expected that these markets make it possible to deal with uncertainties related to the generated power fluctuatio...