The microgrid system (MGS) is composed of various equipments such as photovoltaic, cogeneration, storage battery. The operation of MGS is complicated; therefore it is difficult to optimize the operation to control each facility. In this study, we propose an optimal operation control method utilizing particle swarm optimization (PSO), known as a heuristic method. The advantage of the proposed method is that the complex operation of MGS can be formulated as it is. As a result of simulation and actual operation comparing optimal operation, using the proposed method and conventional scheduled operation, optimal operation can operate the microgrid system efficiently.
Electrical discharge and electrostatics are used for the industrial application of a copying machine and electrostatic spraying. However, the electrical discharge and electrostatics occasionally cause malfunction or failure of electronic equipment. When a human body moves in an office, it is electrified up to 10kV or more. A microelectronic device used in the electronic equipment causes an error owing to the voltage of less than 10V. When the charged human body moves near the electronic equipment, high induced voltage is generated in the metal box. Comprising electronic equipment; the box is occasionally used at the floating potential of an ungrounded condition. The induced voltage generated for the ungrounded metal box is higher than that generated for the grounded metal box. The results show that the induced voltage generated in an ungrounded metal box is 120% of the inverse polarity against a charged body when the charged body moves away from the box. The induced voltage generated in the ungrounded metal box is higher than that generated on the box. These results would be helpful in designing electronic equipment without malfunctions or failure.
Static electricity is used for industrial application of copiers etc. However, such applications could experience an electrostatic accident such as a malfunction or failure of the electronic device. For example, when a charged object, such as a charged human body, exists near a metal housing case, such as an electronic device, an electrostatically induced voltage is generated in the metal case. In general, a malfunction or failure of electronic parts is occasionally caused by a voltage of less than 10V. On the one hand, the voltage of a walking human body in an office with an air conditioner could occasionally exceed 10kV. Very often, an office premises comprises several ungrounded metal housing cases with different volumes (depths). In this study, the relationship between the induced voltages and volume (depth) of a metal case was experimentally determined when a charged object moved away from the metal cases of different volumes. The result shows that the induced voltage in the metal case is 1.4 times higher than the induced voltage on the metal case. The induced voltage in the metal case is overall 0.6 times the reverse voltage polarity against the voltage of the charged object when the volume (depth) of the metal case increases. The result of this study will be helpful for considering the preventive measures of a malfunction or failure of electronic equipment caused by the movement of a charged body.
Recently, renewable energy is being widely used in Japan. The main reason for the widespread use of solar power generation is the feed-in tariff (FIT); however, the FIT program is reaching maturity for some households at the end of 2019. In many cases, the purchase price of 1kWh after the FIT expires will be less than 1/3; therefore, the motivation of prosumers to sell electricity will decrease. In addition, the current electricity infrastructure in Japan assumes that electricity is supplied in one direction from the power plant to the customer. There is a concern that voltage and frequency disturbances may occur when electricity generated on the edge side is fed to the grid. In order to address this problem, several previous studies have been conducted to reduce the surplus power in the grid through power distribution using a P2P power trading system. However, they have not been able to easily reflect participants' preferences against bids. This paper proposes a method that allows users to easily configure the characteristics of the bidding agent, assuming that the P2P power trading agent performs transactions automatically.
In recent years, it has been established that the equipment of smart highways should be reliable. At present, telecommunication facilities are becoming obsolete, and urgent maintenance is required. Conservation is carried out mainly through post-maintenance however, it is necessary to consider “preventive maintenance” which is planned before failure. Therefore, we apply a mining technique to the failure data, create a model for predicting deterioration timing, and construct a safety and security environment for road facilities.
This paper describes the procedures of demand responses (DR) that are invoked in tight supply-demand situations for electrical power supply by using the procedure of Open ADR and FSGIM standardized by ASHRAE. The operation procedures of DR at the demand side has two processes, initiation process and execution process. This paper also describes a concrete technique to control loads at the demand side and to aggregate power consumption data. An electrical power supply and demand adjustment system for TESS by using BACnet communication protocol.
This paper describes a high-frequency-isolation circuit that uses a three-phase transformer with a zero-phase current. The proposed circuit contains a bidirectional chopper circuit and a three-phase high-frequency isolation circuit. The bidirectional chopper circuit controls the DC bus voltage of the first circuit independent from the input voltage source. Thus, the ratio of the DC bus voltage of the first circuit to that of the second circuit can be controlled, which is important in controlling the high-frequency isolation circuit. This study theoretically analyzes the proposed circuit and obtains typical circuit waveforms by simulation. In addition, experimental results using the proposed circuit are discussed. The efficiency of the proposed circuit is measured and compared for each DC bus voltage value. As a result, the proposed circuit can be effectively used for demand control such as in energy storage systems including battery PCS because of its high efficiency using a full-ranged soft-switching technique by controlling the DC bus voltage.
A train schedule in Japan includes regular trains which is fixed on annual basis and pre-planned extra trains whose operation dates are not predetermined. Accordingly, in order to provide efficient transport services, a plan for the daily operation of extra trains must be established based on accurate passenger demand fluctuations forecasts by day/time. Therefore, we developed a method to forecast for the demand fluctuation by day/time on a certain day in the future. The method was developed by combining several fundamental waves, which are extracted by applying independent component analysis to actual ridership records with calendar information, and information on events which was held in target areas. We confirmed that the method has high accuracy by verifying its reproducibility and forecasting accuracy. In addition, the extra trains' operation planning system, which implements the forecasting method, can estimate the load factor of all trains between stations on the planning schedule based on the forecasted demand fluctuations. Then, the system can suggest an optimal extra trains' operation plan based on these values. We estimated the load factor based on forecasted demand fluctuations with the system, and we verified its accuracy. As a result, we confirmed that we can estimate the load factor with high accuracy.
A friction compensation control method based on funnel control has been developed that achieves a pre-specified transient and steady-state performance. The proposed control method has the following features: (1) the controller is designed using a backstepping method, (2) the friction characteristic is represented by the LuGre model, (3) the nonlinear characteristic of the LuGre model is approximated by a neural network, and (4) the weights of the neural network are estimated adaptively. To verify the effectiveness of the proposed control method, experiments were performed using a positioning stage. As a result, it was confirmed that the proposed control method could achieve the pre-specified transient and steady-state performance even when the dynamic behavior of nonlinear friction changed.
This letter proposes a reluctance-network-analysis (RNA) model of coils for wireless power transfer systems in order to reduce the design time for the coils. The coils are expressed as a number of magnetic circuits. As a result, self-inductance and mutual inductance values obtained using the RNA model agree well with the experimental values within a 10% of the error when the number of units of the RNA model is more than 195.
Our research focuses on the compensation performance of fundamental reactive, unbalanced active, and harmonics currents with constant dc-capacitor voltage control of the smart charger for electric vehicles in single-phase three-wire distribution feeders.