Design and Simulation of a Electrorheological(ER) Control High Voltage Power Supply

Few applications with electrorheological （ER） fluids have been found in industry. One reason is high voltage power supplies cannot meet the requirement for ER effect. In this paper, an ER control high voltage power supply for engineering application was designed which reduced power wastage by adopting soft switch technology; lessened its volume to satisfy micromation when adopting the planar transformer and improved its response character- istic by choosing an assistant discharging circuit. Simultaneously, a simulation analysis has been carried out. As results, the output voltage of this high voltage power supply is 5 kV, and the voltage can be continuously regulated and the voltage ripple is only 0. 7 %, so the requirement of stability is also achieved.

A high stability high voltage power supply design for HEPS injection system

Purpose The high energy photon source(HEPS)uses the on-axial injection scheme.There are two designs in this injection scheme that are critical to the performance of the HEPS injection system.One is the strip line kicker and another is the high voltage fast pulse power supply system.In the high voltage fast pulse power supply system,the design of high voltage power supply is very important.The output voltage stability of high voltage power supply directly affects the stability of the pulse amplitude of the injection system.Methods A high voltage power supply with high output voltage stability is designed in this paper,and the scheme is given.The correctness of the design scheme is verified by simulation experiments.Result A prototype is built for full test.The test results showed that the output voltage stability is lower than 58 ppm.The output voltage is 6.4 mV(f≤3 kHz)/113.2 mV(f>3 kHz).Conclusions The designed high voltage power supply can fully meet the requirements of the HEPS injection system.

Experiment and Operation of a LHCD-35kV/2.8MW/1000s High-Voltage Power Supply on HT-7 Tokamak

A -35 kV/2.8 MW/1000s high-voltage power supply (HVPS) for HT-7 superconducting tokamak has been built successfully. The HVPS is scheduled to run on a 2.45 GHz/1 MW lower hybrid current drive (LHCD) [1] system of HT-7 superconducting tokamak before the set-up of HT-7 superconducting tokamak in 2003. The HVPS has a series of advantages such as good steady and dynamic response, logical computer program controlling the HVPS without any fault, operational panel and experimental board for data acquisition, which both are grounded distinctively in a normative way to protect the main body of HVPS along with its attached equipments from dangers. Electric power cables and other control cables are disposed reasonably, to prevent signals from magnetic interference and ensure the precision of signal transfer.This paper involves the experiment and operation of a 35 kV/2.8 MW/1000s HVPS [2] for 2.45 GHz/1 MW LHCD system. The reliability and feasibility of the HVPS has been demonstrated in comparison with experimental results of original design and simulation data.

Multilevel Current Source Converters for High Power Medium Voltage Applications

In medium voltage high power applications,multi-level current source converters(CSCs)are good candidate to increase system power region,reliability,and the quality of output waveforms.Compared with widely researched voltage source multi-level converters(MLCs),the current source MLCs have the advantages of inherent short-circuit protection,high power capability and high quality of output current waveforms.The main features of MLCs include reduced harmonics,lower switching frequency and reduced current stress on each device which is a particularly important for high power application with low voltage and high current requirements.This paper conducts a general review of the current research about MLCs in higher power medium voltage application.The different types of parallel structure based MLCs and the modulation methodologies will be introduced and compared.Specifically,the circuit analysis of the common-mode(CM)loop for parallel structures will be conducted,the common-mode voltage(CMV)and circulating current suppression methods developed on the base of multilevel modulations will be addressed.

Failure Analysis of Ceramic Substrates Used in High Power IGBT Modules

High voltage power modules are used in numerous applications to build high power converters. Technically, these modules are made of different materials and among them, dielectric materials are organic and inorganic. Organic insulators (gels) are used to avoid corona discharges in the vicinity of connecting wires and high voltage dies (diodes and transistors) and to protect them from moisture and contaminants. Inorganic insulators (ceramic substrates) are used to insulate the high voltage which dies from the grounded elements and to transfer heat to the heat sink. Despite being used since the late 90s, there is a lack of fundamental knowledge about the electrical properties of these substrates. Consequently, manufacturers tend to assure the reliability by over sizing them. As there are no clear rules for how to do that, failures occur, leading to the converter shutdown. The aim of this study is to bring new information about the understanding of the dielectric strength of ceramic materials used in these modules. We have focused our work on the correlation between the mechanical and the dielectric properties of ceramics by using relevant experiments. We provide new information about the impact of existing cracks on the ceramic dielectric failure, according to the electromechanical breakdown model. Our conclusions bring crucial information about the precautions to be taken during manufacturing and implementation of these substrates in power modules to reduce the likelihood of the particular causes of failure.

The Design of PSM-Based ECRH Power Supply Control System

Electron cyclotron resonance heating (ECRH) system is one of the most important Tokamak auxiliary heating methods. However, there are growing demands for ECRH system as the physical experiments progress which meanwhile adds the difficulty of designing and building the control system of its power source. In this paper, the method of designing a control system based on Single Chip Microcomputer (SCM) and Field Programmable Gate Array (FPGA) is introduced according to its main requirements. The experimental results show that the control system in this paper achieves the conversion of different working modes, gets exact timing, and realizes the failure protection in 10us thus can be used in the ECRH system.

Hybrid Simulation of ±500 kV HVDC Power Transmission Project Based on Advanced Digital Power System Simulator

In order to effectively imitate the dynamic operation characteristics of the HVDC （high voltage direct current） power transmission system at a real ±500kV HVDC transmission project, the electromechanical-electromagnetic transient hybrid simulation was carried out based on advanced digital power system simulator （ADPSS）. In the simulation analysis, the built hybrid model＇s dynamic response outputs under three different fault conditions are considered, and by comparing with the selected fault recording waveforms, the validities of the simulation waveforms are estimated qualitatively. It can be ascertained that the hybrid simulation model has the ability to describe the HVDC system＇s dynamic change trends well under some special fault conditions.

High voltage generator circuit with low power and high efficiency applied in EEPROM

This paper presents a low power and high efficiency high voltage generator circuit embedded in electrically erasable programmable read-only memory（EEPROM）.The low power is minimized by a capacitance divider circuit and a regulator circuit using the controlling clock switch technique.The high efficiency is dependent on the zero threshold voltage（V_（th）） MOSFET and the charge transfer switch（CTS） charge pump.The proposed high voltage generator circuit has been implemented in a 0.35μm EEPROM CMOS process.Measured results show that the proposed high voltage generator circuit has a low power consumption of about 150.48μW and a higher pumping efficiency（83.3%） than previously reported circuits.This high voltage generator circuit can also be widely used in low-power flash devices due to its high efficiency and low power dissipation.

Experimental Investigation of the Effects of Various Plasma Actuator Configurations on Lift and Drag Coefficients of a Circular Cylinder Including the Effects of Electrodes

In this paper, the effects of the existence of plasma actuator electrodes and also various configurations of the actuator for controlling the flow field around a circular cylinder are experimentally investigated. The cylinder is made of PVC （Polyvinyl Chloride） and considered as a dielectric barrier. Two electrodes are fiush-mounted on the surface of the cylinder and are connected to a DC high voltage power supply lbr generation of electrical discharge. Pressure distribution results show that the existence of the electrodes and also the plasma are able to change the pressure distribution around the cylinder and consequently the lili and drag coefficients. It is found that the effect of the existence of the electrodes is comparable with the effect of plasma actuator in con- trolling the flow field around the cylinder and this effect is not reported by other researchers. Eventually it is concluded that the existence of the electrodes or any extra obiects on the cylinder and also the existence of the plasma are capable of changing the flow field structure around the cylinder so that the behavior of the lift and drag coefficients of the cylinder will be changed significantly.