This paper develops a superior injector driving circuit for a 500c.c. motorcycle GDI engine. The POWER MOSFET component is introduced in the design of the three-pulse injector driving circuit. Experiments for the designed electric driving circuit are investigated to verify its feasibility. The experiments of the H.P. injector driving circuit are conducted for the fuel injection quantity of the H.P. injector under 80~100 bar fuel pressure, 1200~2000 μs injection pulse duration and DC 55~65V power supply voltage. PWM control is introduced to the last pulse 3A holding current for fast cut-off response time of the H.P. injector. Next, Taguchi method was used to lead the design of experiments (DOE). The fuel injection quantities were measured in the various control parameters as engine speeds, power supply voltages, injector driving currents, and fuel supply pressures by the designed injector driving circuit. Effect of these control parameters of the high-pressure (H.P.) injector driving circuit on the fuel injection quantity are analyzed in the paper. Taguchi orthogonal array optimizes the operating parameters of the H.P. fuel injecting system. Results show that the three-pulse POWER MOSFET injector driving circuit is capable of operating stably and assure the accurate injection quantity of the H.P. injector.

An electric driving circuit for the high-pressure (H.P.) injector is required to be designed to be capable of rapid response and precise air-fuel ratio control for GDI engines. In this study, a three-stage power MOSFETs driving circuit for the H.P. injector is designed and tested to verify its feasibility. The experiments for the fuel injection quantities of the H.P. injector are conducted under the conditions of 60-100 bar fuel pressures, 1200~2000μs injecting pulse durations and DC 40~70V executing supply voltages. Next, PWM control is introduced to the last pulse holding current in the three-stage power MOSFETs driving circuit for the rapid response to turn off the H.P. injector. Also, the measured data of the H.P. injector fed by the three-stage MOSFETs driving circuit are defined as the fuel injection curves. The coefficients of polynomial equations can be determined from the fuel injection curves by the Polynomial Curve Fitting (PCF) method and can be implemented in the developed ECU. The ECU demonstrates the ability to control the fuel injection quantities and injection timing rapidly and precisely.

The paper intends to study the core losses of non-oriented electrical steel laminations under high frequency voltage excitations. The measurement of core losses of the electrical steel laminations in Epstein Frame is implemented step by step from 50 Hz to 5000Hz. The accuracy of results evaluated from Expanded GSE method is compared with those tested by Epstein Frame. The core loss database for three different kinds of medium, medium-high and high quality electrical steel laminations (50CS350, 50CS470, 50CS600) is completed in the paper. Also, 85 test points of core loss data are established in the flux density ranging from 0.3T to 1.8T and in the power supply frequency ranging from 50Hz to 5000Hz. Maximum core loss value is close to 443W/kg. The tested core loss data and the Expanded GSE models are useful and may cover for the applications of large-scale wind-driven generators and general motors. They also enough provide designers with the accurate information to minimize the core losses of wind turbine generators.

A DC/DC voltage booster circuit is essential to design for the high-pressure (H.P.) injector driving circuit since the power supply voltages for various H.P. injectors are DC 60~90 V rather than DC 12~14V battery voltages. The DC 12~14V battery voltages have to be boosted up to the stable DC 60~90 V voltages supply for being able to drive various H.P. injectors. The new H.P. injector driving circuit consists of a voltage booster circuit and an originally designed three-stage power MOSFETs injector driving circuit to control the dc-link power supply voltage. The dynamic performance of a H.P. injector driven by the designed electrical driving circuit with the voltage booster are simulated and analyzed. The stability and electrical characteristics for the voltage booster under various injection pulse durations and engine speeds are investigated. The fuel injection quantities, supply voltages and injector driving currents of the H.P. injector fed by the new injector driving circuit is illustrated and analyzed in the paper. The experimental results show that this injector driving circuit with a newly designed voltage booster is capable of operating stably to drive the H.P. injector and obtain the accurate fuel injection quantities in the air-fuel ratio control of engines.

The paper is examined to establish the optimal set of control parameters for the design of a 3MW direct-drive permanent magnet synchronous generator by applying the Taguchi method. Taguchi orthogonal array is employed to determine the optimal combination of design parameters, including: steel lamination material, applied voltage, slot number, diameter of air-gap, magnet pole materials, magnet pole depth, stator outer/inner diameter, and length of stator core under the rated rotating speeds of the generator. Next, core loss database of used electrical steel laminations in generator was investigated. Effect of these control parameters of the permanent-magnet synchronous generator on the output power and efficiency are also analyzed in the paper. Results show that the designed 3MW direct-drive permanent magnet synchronous generator is capable of operating stably and assure the adequate 3MW power output and good efficiency greater than 95%.