K. Tajima

One Method For Calculating Flux-MMF Relations Hip Of Orthogonal-core

One method for calculating flux-MMF relationship of an orthogonal core is described. The calculation is based on a three-dimensional magnetic circuit model of the orthogonal core. The model is derived by dividing the orthogonal core, inclusive of the surrounding region, into elements comprising a three-dimensional magnetic circuit. Using this model, the flux-MMF relationship of the orthogonal core with arbitrary dimensions can be calculated from the B-H characteristic of the core material. The calculation method presented is useful for optimum design of devices using an orthogonal core. >

Calculation on Flux-MMF Relationship of Orthogonal-Core

Orthogonal-cores have various potential applications, for instance in parametric transformers and dc-ac converters. The operating characteristics of the devices can be calculated on the basis of the measured relationship of flux to MMF of the orthogonal -core. To achieve optimal design of the applied device, the relationship of flux to MMF must be determined; however, this involves solving a three dimensional nonlinear problem. In this paper, we calculate the flux-MMF relationship based on a magnetic circuit model for the orthogonal-core. The computed results agree well with experiment. The method of this study is shown to be valid for calculation of characteristics and useful for optimal design of application devices.

An Analysis of the Behavior of Orthogonal-Core Type Push-Pull Parametric Transformer with Iron and Copper Losses

This paper describes an analysis of the behavior of orthogonal-core type push-pull parametric transformers, taking the iron loss of the orthogonal-cores and the copper loss of the windings into consideration. The analysis was performed for the magnetic circuit of the orthogonal-core under magnetic saturation and with hysteresis. To improve the accuracy of calculations, the saturation characteristic was approximated by a series which includes terms of up to 21st order in the flux, and the hysteresis curve by a series including terms of up to 5th order in the exciting voltage. The calculated results show good agreement with experimental data. The analytical method presented here is useful for optimizing the design of push-pull parametric transformers.

Transient operation of orthoginal-core type DC-AC converter for photovoltaic power system

Discusses transient operation of the orthogonal-core-type DC-AC converter for a grid-connection-type photovoltaic (PV) power system. In particular, they consider the transient operation when the converter is connected to and disconnected from the utility grid on the basis of simulation and experiment. Furthermore, they examine the converter behavior when a line-to-line fault occurs in the utility grid. It is shown that the DC-AC converter has excellent tolerance for various faults which occur in a PV power system. >

Transient Analysis Of A Push-pull Parametric Transformer At Start-up Time

In this paper, we analyze the transient operation of the push-pull parametric transformer with resistive load at start-up time. The results show that the set-up time remains constant and an overvoltage or overcurrent is not generated at an instant of start-up. So, it is obvious that the push-pull parametric transformer operates in a stable mode as compared with the conventional transformer at start-up time.

An ac System Interruption Analysis of an Orthogonal-Core Type dc-ac Converter

This paper describes an analysis of the transient response of an orthogonal core-type dc-ac converter for use in a photovoltaic power system. The analysis is based on a numerical model of an orthogonal core for use with the SPICE circuit analysis program. As one example of such a transient response analysis, we calculated the voltage and current of the dc-ac converter when its secondary is cut off from the ac system. The calculated results agreed well with measurements. The analytical method presented here is useful for predicting the behavior of a photovoltaic power system at the occurrence of ac system interruptions, line-to-line faults and various other faults.

Optimum Design of an Orthogonal Core Based on a Magnetic Circuit

The operating characteristics of parametric transformers and dc-ac converters with an orthogonal core depend heavily on the core shape. Accordingly, to obtain the optimal design for such devices, the quantitative relationship between the orthogonal core shape and the operating characteristics of the application device are determined. In this paper, the application characteristics are discussed analytically in terms of the orthogonal core shape, with reference to a magnetic circuit model of the core.

Analysis of Parametric Transformer with Rectifier Load

This paper describes a push-pull parametric transformer constructed using a pair of orthogonal-cores. The operating characteristics of the parametric transformer with a rectifier load were analyzed based on SPICE simulations. The analysis results show good agreement with experiment. It was found that the input surge current of the full-wave rectifier circuit with a smoothing capacitor can be compensated by the parametric transformer. Use of the parametric transformer as a power stabilizer is anticipated owing to its various functions, such as for voltage regulation and overload protection.

Orthogonal-Core Type Three-Phase dc-ac Converter

In a previous paper, the authors proposed an orthogonal-core type dc-ac converter for use in photovoltaic power systems. The dc-ac converter has such desirable features as a simple construction, high degree of safety, and, ease of maintenance. The operating characteristics of a single-phase converter for residential photovoltaic power systems have also been reported. In this paper, we discuss the basic operation of an orthogonal-core type dc-ac converter for a three-phase power system based on simulations and experiments. An optimal construction of the orthogonal-core type three-phase dc-ac converter has been developed.