Yen-Nien Wang

A new ZVS-PWM full-bridge step-up/down converter

A novel zero-voltage-switching pulse-width-modulation (ZVS-PWM) full-bridge transformer-isolated step-up/down converter is proposed in this paper. The output voltage of the proposed converter can be larger or lower than the DC input voltage, depending on the instantaneous duty-cycle. This property is not found in the classical full-bridge transformer-isolated converter. Furthermore, in the proposed converter, besides operating at constant frequency, all semiconductor devices operate at soft-switching without additional voltage stress and current stress. An average approach is employed to analyze the system. A design example of 1000 W ZVS-PWM full-bridge converter is examined to assess the converter performance.

Artificial immune algorithm based obstacle avoiding path planning of mobile robots

This investigation studies the applicability of using mobile robots with artificial immune algorithm (AIA) based obstacle-avoiding path planning inside a specified environment in real time. Path planning is an important problem in robotics. AIA is applied to determine the position and the angle between a mobile robot, an obstacle and the goal in a limited field. The method seeks to find the optimal path. The objectives are to minimize the length of the path and the number of turns. The results of the real-time experiments present the effectiveness of the proposed method.

Plan on Obstacle-Avoiding Path for Mobile Robots Based on Artificial Immune Algorithm

This paper aims to plan the obstacle-avoiding path for mobile robots based on the Artificial Immune Algorithm (AIA) developed from the immune principle; AIA has a strong parallel processing, learning and memorizing ability. This study will design and control a mobile robot within a limited special scale. Through a research method based on the AIA, this study will find out the optimum obstacle-avoiding path. The main purpose of this study is to make it possible for the mobile robot to reach the target object safely and successfully fulfill its task through optimal path and with minimal rotation angle and best learning efficiency. In the end, through the research method proposed and the experimental results, it will become obvious that the application of the AIA after improvement in the obstacle-avoiding path planning for mobile robots is really effective.

Improved Microwave Dielectric Properties of La(Mg0.5Sn0.5)O3 Ceramic with Sr2+ Substitution

The microwave dielectric properties of La(Mg0.5−xSrxSn0.5)O3 ceramics were examined with a view to their exploitation for wireless communications. The La(Mg0.5−xSrxSn0.5)O3 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The La(Mg0.5−xSrxSn0.5)O3 ceramics contained La2Sn2O7. An apparent density of 6.56 g/cm3, a dielectric constant (ϵ r ) of 20.5, a quality factor (Q × f) of 107,900 GHz, and a temperature coefficient of resonant frequency (τ f ) of −84 ppm/°C were obtained for La(Mg0.4Sr0.1Sn0.5)O3 ceramics that were sintered at 1500°C for 4 h.

Work in Progress: A Joint Effort of Lunghwa University and Holtek Semiconductor Inc. on Improving Microcontroller Education

Making profits is the key objective for most industrial companies, but in our case, it is sacrificed to educate qualified and creative microcontroller hardware and firmware engineers. Holtek semiconductor Inc. donates its microcontroller integrated design modules and technical support to setup a laboratory in Lunghwa University for learning activities. Lunghwa University offers its resources, including teachers and facilities, to redesign course contents, hardware and software teaching materials, and propose a new program for the design of microcontroller and embedded systems. A creativity contest with high prize (SD 18000 in total) for the design of microcontroller and embedded systems using Holteks microcontrollers is also initiated to attract more senior high school and university students to show their creativities and technical skills. The proposed program will also encourage enrolled students to win certificates provided by the Taiwan Embedded Microcontroller Development Institute, because the Institute is supported by the government and local industries

A novel single-stage ZVS-PWM buck-boost inverter

A novel single-stage zero-voltage-switching pulse-width-modulation (ZVS-PWM) buck-boost inverter is proposed in this paper. The output voltage of the proposed inverter can be larger or lower than the DC input voltage, depending on the instantaneous duty-cycle. This property is not found in the classical voltage source inverter, which produces an AC output instantaneous voltage always lower than the DC input voltage. Furthermore, in the proposed inverter, besides operating at constant frequency, all semiconductor devices operate at soft-switching without additional voltage stress and current stress. An average approach is employed to analyze the system. A design example of 1000 W ZVS-PWM buck-boost inverter is examined to assess the inverter performance.