Development of 8 MW Power Supply Based on Pulse Step Modulation Technique for Auxiliary Heating System on HL-2A

The high voltage power supply （HVPS） based on pulse step modulation （PSM） has already been developed for the auxiliary heating system on HL-2A. This power supply consists of many switch power supplies, and its output voltage can be obtained by modulating their delay time and pulse widths. The PSM topology and control principle are presented in this paper. The simple algorithms for the control system are explained clearly. The switch power supply （SPS） module has been built and the test results show it can meet the requirements of the auxiliary heating system. Now, 112 SPS modules and the whole system have already been developed. Its maximum output is about 72 kV/93 A. The protection time is less than 5 t＊s. The different outputs of this power supply are used for the electron cyclotron resonant heating （ECRH） system with different duty ratios. The experimental results of the entire system are presented. The results indicate that the whole system can meet the requirements of the auxiliary heating system on HL-2A.

Optimization Design for a High Voltage DC Power Supply Module Based on PSM Technology

Pulse step modulator （PSM） topology is applied to the EAST auxiliary heating system, which consists of a neutral beam injection （NBI） and the related microwave heating system. This paper firstly analyzes the merits and demerits of the traditional PSM modules adopted by other international companies, and then optimizes the topology of the module using the analysis results. Finally, a new topology for the PSM module （a three-phase neutral-point diode-clamped rectifier） is proposed. This new module overcomes the problems of traditional modules and has better cost-effective performance. The experimental results verify that the new module is feasible for engineering applications.

Intelligent Solar Chasing Street Light System Design and Fabrication Summaries

This project adopts an advanced microcontroller as the core control unit,which accurately commands the servo drive,realizes the real-time light chasing and charging function of the solar panel,and effectively manages the power supply system of the street light.At the same time,the system is able to continuously monitor the operation status of the servo within the range of 0°to 180°to ensure that it is trouble-free and not offline.The hardware system construction consists of five modules:a power module,solar panel module,servo module,street light module,and Organic Light-Emitting Diode(OLED)display module.Each module works together to support the stable operation of the whole system.The system workflow is to accurately determine the direction of the light source by collecting real-time light intensity data through four precision photoresistors.Subsequently,the microcontroller intelligently controls the helm module based on these data to drive the solar panel to rotate within a range of 180°to accurately track the sun’s orientation.The street light provides two lighting modes,automatic and manual,to meet the needs of different scenarios.During the daytime,the solar panels work actively to monitor and collect solar energy efficiently in real-time,meanwhile,when night falls,the solar panels switch to standby mode and the streetlights light up automatically,illuminating the road ahead for pedestrians.Compared with the traditional solar street lights on the market,the intelligent solar light chasing road system introduced in this project has significant advantages.Its unique light-chasing algorithm enables the solar panel to continuously track the light source from sunrise to sunset,thus significantly improving the charging efficiency.Compared with traditional street lights,the biggest advantage of this project is the proposed light-chasing algorithm,which can always charge from sunrise until sunset,making the charging efficiency increase by 38%to 47%.The charging efficiency is 20%to 38%higher than that of traditional street lamps.Simultaneously,the biggest advantage of this project is that the power storage capacity is higher than 35%of the traditional solar street light.Bringing users a more durable and stable lighting experience.

Derivative Derivative-Based Envelope Design Technique for Wideband Envelope Tracking Power Amplifier with Digital Predistortion

A novel envelope design for an envelope tracking(ET)power amplifier(PA)based on its derivatives is proposed,which can trade well off between bandwidth reduc-tion and tracking accuracy.This paper theoretically analyzes how to choose an envelope design that can track the original envelope closely and reduce its bandwidth,and then demonstrates an example to validate this idea.The generalized memory polynomial(GMP)model is applied to compensate for the nonlinearity of ET PA with the proposed envelope design.Experiments are carried out on an ET system that is operated with the center fre-quency of 3.5 GHz and excited by a 20 MHz LTE signal,which show that the proposed en-velope design can make a good trade-off between envelope bandwidth and efficiency,and satisfactory linearization performance can be realized.