Katsuhiro Ichiyanagi

Notice of Retraction Research of PV Model and MPPT Methods in Matlab

The power generated by the PV generator depends on the irradiance, temperature, and surface conditions. The PV generator has a nonlinear characteristic, and the power has a maximum power point or multi-local maximum power points under different conditions. Various MPPT methods have been reported, in order to confirm the effectiveness of each control method, experimental or simulation analysis is used, from economical point of view, simulation analysis is more effective. In this paper, a versatile, accurate Matlab/Simulink PV model suitable for use by power electronics specialists has been developed, and has been designed for easy implementation on Matlab/Simulink platform; conventional MPPT methods and MPPT methods suitable for partial shading conditions can be simulated by using this PV model.

PEM Fuel Cell modeling and parameter influences of performance evaluation

Fuel cell (FC) systems have been showing up as a promising alternative due their high efficiency, low aggression to the environment, excellent dynamic response, and superior reliability and durability. This paper introduces the electrochemical model of FC and establishes the Simulink model based on it. The results of the model are used to predict the output voltage, efficiency, and power of FC as a function of the actual load current and of the constructive and operational parameters of the cells. Detailed simulation researches on polarization curves have been carried through for FC performances boosting. Parameter influences of FC are mainly discussed on the dynamical performance of PEMFC and some parameters which might be despised but very important are pointed out, especially. Corresponding dynamic behaviors of a typical 500-W BCS stack are presented. In the end, control strategies are designed for FC operation optimization, and some accidental cases are pointed out.

A study of electric power quality using storage system in distributed generation

This paper describes a method to improve the power quality of a distributed generation (DG) power system. The proposed method uses a power storage system with DG. Here, DG is assumed the renewable energy systems such as photovoltaic generation (PV), wind power generation (WG) and fuel cells (FC), etc. The effect to use the storage battery is shown by the following two experiments. One case is the examination of a power transmission simulator. Another case is an experiment in a small-scale actual system. The electric power quality (frequency, voltage) is observed, when the storage battery have been introduced or not. In case of a power transmission simulator, the frequency control is executed using two methods; a power demand estimation method and a proportion control method that uses frequency deviation. The control of the storage battery is executed by using these controls. Another case is an examination for a real power system, which is the 12th pavilion of Aichi Institute of Technology (AIT). In this pavilion, photovoltaic generation (PV), wind power generation (WG) and storage batteries have been introduced. And the electric power is supplied by these sources. The electric power qualities in two cases were compared. One case is the storage battery is introduced. Another case is without the storage battery. The storage battery executes the control that maintains the voltage in the power system. As a result, it has been understood that the electric power quality has improved, when the storage battery is introduced.

A Modified Method to Generate Typical Meteorological Years from the Long-Term Weather Database

A modified typical meteorological year (TMY) method is proposed for generating TMY from practical measured weather data. A total of eleven weather indices and novel assigned weighting factors are applied in the processing of forming the TMY database. TMYs of 35 cities in China are generated based on the latest and accurate measured weather data (dry bulb temperature, relative humidity, wind velocity, atmospheric pressure, and daily global solar radiation) in the period of 1994–2010. The TMY data and typical solar radiation data are also investigated and analyzed in this paper, which are important in the utilizations of solar energy systems.

Study of load frequency control for a microgrid

This paper describes a method to enhance the load frequency control in a power system with distributed generations (DG). In this paper, a power storage system is used with solar photovoltaic generations and wind power generations. The microgrid system at Aichi Institute Technology in Japan is used as a simulation model. For each simulation, which was carried out by using a power transmission simulator, the model of the microgrid included one DG and a storage system. The effectiveness of load frequency control using the storage system was examined. It was confirmed that the electric power quality improves when load frequency control is carried out with the storage system.

Study of AC/DC power supply system with DGs using parallel processing method

This paper proposes a new AC/DC power supply system with DGs using the parallel processing method. The purpose of this system is to supply the power without connecting to the utility gird. The DGs consist of photovoltaic (PV) and wind generators (WG), and the main energy source of this system is the DGs and the UPS battery. When the system does not get enough energy from the DGs, and the power supply of the battery runs out, this system connects to the utility grid and begins to charge the battery and supply to the load. In this study, we focused on the AC power supply and DC power supply from DGs. Then, the converter of DGs uses two kinds of DC/DC type and DC/AC type. Also, the load uses two kinds of DC load and AC load. The proposed the power system has been operated with the actual loads of 20 kW in the campus of the Aichi Institute of Technology.

Load frequency control using storage system for a micro grid

This paper describes a method to enhance the load frequency control in a power system with distributed generations (DG). In this paper, a power storage system is used with photovoltaic generation and wind power generation. The microgrid system at Aichi Institute of Technology in Japan is used as a simulation model. For each simulation, which was carried out by using a power transmission simulator, the model of the microgrid included one DG and a storage system. The effectiveness of load frequency control using the storage system was examined. It was confirmed that the electric power quality improves when load frequency control is carried out with the storage system.

Automatic generation control using GA considering distributed generation

This paper examined the automatic generation control method in the power system that introduced distributed generator. Examined content is the case of they distributed generator participated/nonparticipated in the frequency control of the system. Control of the power plant in each area is the case of the control method using the load demand estimation and fuzzy control using GA. To study the effectiveness of the distributed generator, this paper considered the computer simulation 3-area automatic generation control model system which introduced the distributed generator.

Hybrid behaviors analysis of photovoltaic array performance

Photovoltaic cells would operate as a load when local solar irradiation declines in series connection, which would result in damage easily. Nowadays modules are often configured with bypass diodes to provide energy releasing route. Furthermore, blocking diode is connected in series before parallel connection in order to prevent inverse power injection. Based on such configurations, this paper was mainly devoted to present a simplified method for characterizing hybrid photovoltaic performance. Newton-Raphson method was adopted for numerical simulations. It was proven to be suitable and effective in model validation coinciding with manufacturer specification. Furthermore, MPP peak positions were reviewed roundly via simulations of the total characteristic curves, especially the operation mismatches caused by random shadows. Different abilities under diverse series/parallel patterns were also investigated for comparison. Researches indicate that: firstly, traditional monotone algorithms of MPPT could be invalid for detecting false maximum only; secondly, the “doorsill effect” of local irradiation intensities, namely that global power output might not be influenced by changes of local shadows; finally, suggestions are put forward that parallel connection should be ranked prior consideration with whole array design, to boost power output relatively.

A study on power system transient stability due to introduction of superconducting fault current limiters

This paper describes the experimental results by using the power transmission simulators and the computer simulation using EMTDC, about the superconducting fault current limiters (SCFCL) on improvement of power system stability and suppressing fault currents. The experiments and the simulations in this paper were carried out using the R-type and L-type SCFCL. The R-type SCFCL is simulated by using a resistor and an electromagnetic contactor with thyristors. The L-type SCFCL is simulated by using a reactor and an electromagnetic contactor with thyristors. It is found that the SCFCL in the electric power system gives the improvement of the suppressing fault current and power system transient stabilities.