O. Ichinokura

A Novel Algorithm for Fast and Efficient Speed-Sensorless Maximum Power Point Tracking in Wind Energy Conversion Systems

This paper proposes a novel solution to the problems that exist in the conventional hill climb searching (HCS) maximum power point tracking (MPPT) algorithm for the wind energy conversion system. The presented solution not only solves the tracking speed versus control efficiency tradeoff problem of HCS but also makes sure that the changing wind conditions do not lead HCS in the wrong direction. It intelligently adapts the variable step size to keep up with the rapid changes in the wind and seizes the perturbation at the maxima to yield 100% control efficiency. For this purpose, a novel peak detection capability has been devised which, in contrast with conventional peak detection, can work robustly under changing wind conditions. The proposed MPPT performs self-tuning to cope with the nonconstant efficiencies of the generator-converter subsystems-a phenomenon quite rarely discussed in research papers so far. In addition, a smart speed-sensorless scheme has been developed to avoid the use of mechanical sensors. The experimental results confirm that the proposed algorithm is remarkably faster and more efficient than the conventional HCS.

Review and critical analysis of the research papers published till date on maximum power point tracking in wind energy conversion system

Maximum power point tracking (MPPT) is a very important necessity in a system of energy conversion from a renewable energy source. Every year a number of publications appear in various journals and conferences claiming to offer better and faster MPPT techniques for wind energy conversion system (WECS). This research paper provides a concise yet comprehensive critical analysis of these techniques with an in-depth review of their strengths and drawbacks. This review is unique as there has been no other research paper so far that offers such a complete and up-to-date investigation of MPPT techniques in WECS. Therefore this research paper can serve as a precise reference for the future research on MPPT for WECS.

Dynamic analysis of interior permanent magnet motor based on a magnetic circuit model

In this paper, we presents a calculation method of the dynamic characteristics of the IPM motor based on the magnetic circuit model.

Analysis of dynamic characteristics of switched reluctance motor based on SPICE

A method for calculating the dynamic characteristics of switched reluctance motor (SRM) has been proposed. The inductance model of SRM that is changed following the rotor position can be estimated from FEM analysis. Based on the model, we design a circuit simulation of SRM using SPICE, which can simulate voltages, currents, torque and rotation speed of the SRM.

A new variable inductor for VAR compensation

A new variable inductor with sinusoidal output is described. The variable inductor is constructed with a pair of orthogonal cores. The secondary AC current is easily controlled by the primary DC current. The secondary current is almost sinusoidal in a wide control region. A prototype circuit for reactive power compensation using the new variable inductor is presented. >

Analysis of orthogonal-core type linear variable inductor and application to VAr compensator

This paper presents a quantitative analysis of the orthogonal-core type linear variable inductor. The orthogonal-core has wedge gaps for reduction of harmonics of the output currents. The analysis is based on a 3-dimensional nonlinear magnetic circuit of the orthogonal-core. Using the magnetic circuit, one can calculate accurately the operating characteristics of the variable inductor. Furthermore, they develop a VAr compensator for a 6.6 kV AC distribution system using the three-phase variable inductor.

A new calculation model of switched reluctance motor for use on SPICE

This paper presents a new calculation model of the switched reluctance motor (SRM) for use on SPICE which is a general-purpose circuit simulation program. In the calculation model, the electric circuit and magnetic circuit of SRM are separated and are coupled by proper controlled sources. Using the SPICE model, we can calculate readily and accurately the dynamic characteristics of the SRM.

A new sensorless drive method of Switched Reluctance Motors based on motor's magnetic characteristics

We propose a new sensorless drive method of Switched Reluctance Motor (SRM) based on motors magnetic characteristics. Some drawbacks of the method using impressed voltage pulse at unenergized phases to detect the magnetic characteristic have been improved. The proposed method has the features: only one unenergized phase has been injected by impressed voltage pulse, that simplifies both hardware and control algorithm, and a new idea to determining the injecting timing for impressed voltage pulse has been introduced, that extremely eliminates the negative torque caused by some residual currents. Because the proposed method is very simple, instead of expensive DSP, the entire experimental system has been implemented in an analog and digital circuit (FPGA: Field Programmable Gate Array).

Optimization of a Switched Reluctance Motor Made of Permendur

A switched reluctance (SR) motor has a doubly salient pole structure. A stator has concentrated windings on each pole, while a rotor is only made of iron core. Therefore, the SR motor is expected as a low cost, extremely robust, variable speed motor. The performance of the SR motor greatly depends on magnetic properties of core material since it consists of only laminated-core and windings. This paper investigates the performance of an SR motor made of permendur which has extremely high saturation flux density and very low core loss. Motor torque, iron loss, and efficiency of the SR motor are estimated by finite element method (FEM). Furthermore, a suitable structure for the SR motor made of permendur is examined based on the design of experiments.

A spice model of orthogonal-core transformers

This paper deals with a numerical model of orthogonal‐core transformers for use in spice. The model was devised on the basis of the magnetic circuit of the orthogonal‐core with the saturation and hysteresis effects. Using the numerical model, the behavior of the dc‐ac converter constructed with the orthogonal‐core transformers and square‐wave transistor choppers was analyzed. The calculated values and measured ones show a good agreement. The method presented here is suitable for the circuit analysis and design optimization of the dc‐ac converter taking account of nonlinear characteristics of the orthognal‐cores and semiconductor devices used in the converter.