CHARACTERITICS OF MODIFIED PD CONTROL OF ELECTROMAGNETIC SUSPENSION SYSTEM FOR NON-CONTACT STEEL PLATE CONVEYANCE

Dehong Xu,Xiao Sun,Wei Feng 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

Based on the linear model of electromagnetic suspension (EMS) system, it is able to be further simplified into a standard second-order model with a modified PD control. In this paper static and dynamic characteristics of EMS with modified PD control are investigated when suspended weight of steel plate changes. A experimental system has been built to verify static and dynamic characteristics of EMS system. Simulation and experiment results are both given.<br/>

A Family of Novel Zero-voltage Switching Three-Phase PWM Converters Topology for Distributed Generation

Dehong Xu,Zhiyuan Ma,Chengrui Du,Min Chen 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Because of the need of energy saving and emission reduction, we see a quick increase of installed renewable energy distributed generation systems. Three phase PWM Grid-side converter is widely used for medium and large capacity distributed generation systems. Traditionally hard-switching three-phase PWM converters are used, which causes severe switching loss, high di/dt and EMI. In this paper, a family of novel zero voltage switching three-phase PWM converter topologies under two types of active clamping are proposed. Novel space vector modulation schemes for the three-phase PWM converter is proposed. With the proposed space vector modulation scheme, the converters can realize zero voltage switching (ZVS) operation for all switching devices while the anti-parallel diode reverse recovery of all switch devices is suppressed. It has features fixed switching frequency, and lower voltage stress of the power switch devices. The different converters in the family are compared with respect to soft switching conditions, stress, adaptability to DC side voltage variation. Prototypes are built to verify the theory.

EXACT ANALYSIS OF A SINGLE SWITCH RESONANT INVERTER

Dehong Xu,Mao Ye 전력전자학회 1995 ICPE(ISPE)논문집 Vol.1995 No.10

This paper presents exact analysis result of the two topologies of single switch circuit Zero voltage swicthing-on condition it, drived Pa­rameters foi circuit design purpose arc plotted. Using the graphs optimum design can obtained Expenment model of 1KW is tested and results are given.

A SINGLE-CHIP-MICROPROCESSOR CONTROLLED PHOTOVOLTAIC AC SUBMERSIBLE SCREW WATER PUMP SYSTEM

Dehong Xu,Rongfang Cai,Jianlong Shao 전력전자학회 1995 ICPE(ISPE)논문집 Vol.1995 No.10

An 1 KWp photovoltaic AC water pump system controlled by a single chip microproces­sor is presented. A submersible screw electric pump is drived by a PWM MOSFET inverter. The PWM control pulse for the inverter is generated by an IC HEF4752. Since the screw pump has constant torque property, a simpler maximum power tracking method without the need of a DC-DC converter, which is called Maximum Frequency Point Tracking(MFPT), is presented, which simplifies the control complexity.

A High Power Density and Efficiency Bi-Directional DC/DC Converter for Electric Vehicles

Xiaoyu Jia,Dehong Xu,Shuailin Du,Changsheng Hu,Min Chen,Ping Lin 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In electric vehicle systems, bi-directional DC/DC converters are used to interface the battery bank with the high voltage DC bus of the inverter. The high power density and high efficiency are required for bidirectional DC/DC converters. This paper discusses the relationship between switching frequency, inductor value and passive components volume. First, the topologies of the system and the converter are presented. Then, the loss breakdown model is provided. A selection for the switching frequency is presented and an option of inductor value is provided to reduce the converter size and to keep the converter efficient. Then the converter layout which further enhances the power density is discussed. Finally, a high power density and high efficiency converter prototype is built, and the efficiency and thermal performance evaluation of the converter at different operating conditions is given.

Switching Noise Suppression for Hybrid IGBT Modules

Nan Zhu,Dehong Xu,Xingyao Zhang,Min Chen,Seiki Igarashi,Tatsuhiko Fujihira 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In a hybrid IGBT module with SiC diodes as free-wheeling diodes, high frequency oscillation occurs during turn-on, which will cause higher EMI noise due to the larger capacitance of SiC diode. To evaluate the influence of gate drive parameters on turn-on oscillation, different gate voltages and gate charge currents are used. It is found that by changing gate drive parameters alone cannot reduce the settling time of the oscillation significantly. Then an oscillation suppression method with damping circuits is proposed. According to the analytical and experimental results, the damping circuits are able to effectively accelerate the damping of turn-on oscillation without significant increase in current overshoot and turnon energy loss. Finally to suppress the turn-on current overshoot, active gate driver method is also used without large increase in the turn-on energy loss. The combination of damping circuit and active gate driver may be an optimized choice to achieve the lowest EMI noise.

A ZVS-SVM Method for Grid Inverter with Extended Power Factor Angle

Yuying Wu,Ning He,Dehong Xu 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Grid inverter is required to generate reactive power to support the power system during grid faults to satisfy the grid code. Therefore the grid inverter should have the ability to operate with wide power factor range. In this paper, a Zero-Voltage-Switching Space Vector Modulation (ZVSSVM) scheme for three-phase ZVS grid inverter with extended power factor angle is proposed. With only one switching operation of the auxiliary switch during one switching period of SVM, ZVS of all switches can be achieved. Stage operations are analyzed and ZVS condition is derived. Finally the proposed ZVS-SVM method is verified by experiments.

Topology of Super Uninterruptible Power Supply with Multiple Energy Sources

Keyan Shi,Haijin Li,Changsheng Hu,Dehong Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The dramatic loss caused by the power blackout in some industrial applications proposes the requirement for an extremely high reliability uninterruptible power supply (UPS). This paper introduces the concept of super uninterruptible power supply (Super UPS). Multiple energy sources are used to obtain a high reliability, long backup time, high surety UPS system. Classifications for energy sources, power conversion stage and power distribution bus line are established to simplify the power conversion architectures. A generic method to classify the architectures for multiple energy source system is presented. Then a system reliability evaluation method based on different architectures is used to analyze the characteristics of different types of topology. Redundant power conversion stage design to enhance the system reliability is discussed. Finally, a high reliability super UPS architecture is proposed.

Design and Control of Bi-directional DC/DC converter for 30kW fuel cell power system

Xiao Li,Wenping Zhang,Haijin Li,Ren Xie,Dehong Xu 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

Fuel cell (FC) power system is considered as an alternative energy power generation system in the future. This paper studies the bidirectional DC/DC converter for a 30㎾ three-phase fuel cell power system. The FC power system is sensitive to load characteristics in stand-alone mode, because rapid change or unbalance of the three-phase load will endanger the safety and expectancy of fuel cell. The bidirectional DC/DC converter with energy storage component is used to provide the dynamic power to avoid fast changing in fuel cell output. In addition, it acts as DC bus capacitors to absorb the low frequency current ripple. Therefore, fuel cell is separated from the low frequency current ripple and large DC bus electrolytic capacitors can be eliminated. Through investigating topology of the bidirectional DC/DC converter, three-level bidirectional DC/DC converter (TLBD) is used for the 30㎾ fuel cell power system. The design and control of the TL-DB is described. TL-DB with its control strategy is verified by the experimental results.

Characteristics of SiC inverter powertrains on common-mode EMI noise

Jia, Xiaoyu,Dong, Bitao,Wang, Hui,Hu, Changsheng,Xu, Dehong The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.2

This paper studies the characteristics of SiC inverter powertrains on common-mode (CM) EMI emission. First, a CM noise source model of an EV powertrain is built. Then, the factors of switching frequency, switching speed, and switching ringing on the CM noise source are analyzed. Finally, experiments on a conducted EMI test-bed are carried out to verify the influence of SiC inverters on conducted CM EMI emission in EV powertrains.