Kazuaki Yuki

Principle of the variable-magnetic-force memory motor

Electrical appliances and electric vehicles (EV) require reduction of electrical consumption. Then, we have developed a novel permanent magnet motor for energy saving. In this paper, we propose the novel motor that can change magnetic flux by a new method magnetizing a permanent magnet and clarify the principle and unique characteristics. Furthermore, the results of analysis and experiments prove that the novel motor can change the flux of permanent magnet on load and has realization for a variable speed drive with high performance.

Study of the Magnetization Method Suitable for Fractional-Slot Concentrated-Winding Variable Magnetomotive-Force Memory Motor

This paper describes a variable magnetomotive-force memory motor with a fractional-slot concentrated winding. We propose a method for optimal control of magnetization suitable for a fractional-slot concentrated winding. Our result shows that variable magnetized magnets are more highly magnetized when a fractional-slot concentrated winding is used than those using the conventional method.

New generation motor for energy saving

Reduction of electrical consumption of a electric vehicle (EV) and electrical appliance is one of solutions for reduction of CO2 gas. Then, we have developed a novel permanent magnet motor for energy saving. In this paper, we propose a novel motor that can change magnetic flux by a new method magnetizing a permanent magnet and clarify the principle and unique characteristics. Furthermore, the results of analysis and experiments prove that the novel motor can change the flux of permanent magnet on load and has realization for a variable speed drive with high performance.

Application of speed sensorless control to railway traction field

We have developed a novel drive system without using speed sensors in the railway traction field. In this time, we carried out some running tests in the field using an actual train to verify the total stability and performance of the proposed system. Especially, these experiments were executed under 4 induction motors driven in parallel by only one VVVF inverter. It is concluded that the proposed system was so stable in all speed regions including wide flux weakening region using 1 pulse mode, and its adhesion control performance was almost at the same level as the conventional drive system.

An application of the induction motor speed sensor less control to railway vehicle traction system

For railway vehicle traction purpose, slip frequency of induction traction motors are controlled with detecting rotor frequency by pulse generators or PGs as the speed sensors. Applying the speed sensor less control method to the railway vehicle traction to eliminate the PGs, we expect to improve cost efficiency and reliability of the traction control system. Though speed sensor-less control methods are popular in general industrial application purpose, some novel control functions may be added and its compatibility is verified to cope with the problem particular in railway vehicle traction application. In this paper, we present the result of the application to railway vehicle traction control with theoretical study and tests.

Real time simulator for railway traction and auxiliary power unit control applications

This paper mentions about applications of a real time simulator (RTS) for railways traction and auxiliary power unit (APU) control. The RTS allow us to examine the control algorithm before on-site examination. This improves the efficiency of control algorithm development. Mathematical models of traction control system and APU are programmed in a field programmable gate array (FPGA) in order to realize the simulation precision of 1 microsecond. Various examples of real-time simulations are included in this paper to confirm the effectiveness of the RTS.

Noise reduction method by injected frequency control for position sensorless control of permanent magnet synchronous motor

This paper proposes a novel noise reduction method by injected frequency control for position sensorless control of permanent magnet synchronous motor (PMSM). The proposed method reduces acoustic noise caused by injected high-frequency voltage without reducing the accuracy of rotor position estimation. The proposed method is verified by numerical simulations and experiments using a 0.8kW-PMSM.

Evaluation of induction motor speed sensorless control for railway vehicle traction system

This paper evaluates the control performance of a speed sensorless induction motor control method for railway vehicles traction, compared to vector control system with pulse generators as speed sensors, from the view points of flux behavior. The speed sensorless strategy is based on the rotor flux induced voltage and is expected its high performance as well vector control system with pulse generators. The control performance is verified from the viewpoint of the rotor flux, because the speed sensor is used for controlling the rotor flux with the indirect vector control strategy. This paper provides the way how to evaluate the speed sensorless control on the railway vehicle traction system. First, the proposed speed sensorless control strategy for railway vehicles is presented. Then, its basic control characteristic is evaluated by numerical simulation and further control functions that are peculiar to the railway traction application are rated by the experiments

The study of magnetic polarity detection method for permanent magnet reluctance motor

This paper studies a magnetic polarity detection method for permanent magnet reluctance motor (PRM). Inductance characteristic of PRM is different from that of common interior permanent magnet synchronous motor. The inductance characteristic of PRM is verified by electromagnetic field analysis. Moreover, this paper proposes novel magnetic polarity detection method using the inductance characteristic of PRM. The proposed method is verified by experiments using a 90-kW PRM.