A Novel Half-Bridge Power Supply for High Speed Drilling Electrical Discharge Machining

High Speed Drilling Electrical Discharge Machining (HSDEDM) uses controlled electric sparks to erode the metal in a work-piece. Through the years, HSDEDM process has widely been used in high speed drilling and in manufacturing large aspect ratio holes for hard-to-machine material. The power supplies of HSDEDM providing high power applica-tions can have different topologies. In this paper, a novel Pulsed-Width-Modulated (PWM) half-bridge HSDEDM power supply that achieves Zero-Voltage-Switching (ZVS) for switches and Zero-Current-Switching (ZCS) for the dis-charge gap has been developed. This power supply has excellent features that include minimal component count and inherent protection under short circuit conditions. This topology has an energy conservation feature and removes the need for output bulk capacitors and resistances. Energy used in the erosion process will be controlled by the switched IGBTs in the half-bridge network and be transferred to the gap between the tool and work-piece. The relative tool wear and machining speed of our proposed topology have been compared with that of a normal power supply with current limiting resistances.

Power Supply of Macro-Micro Driven Linear Piezoelectric Motor

To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement,a digital signal processing(DSP)based macro and micro power supply is designed,which fits the new linear piezoelectric motor.The power supply comprises a control circuit,a voltage conversion circuit,an amplifier circuit,a half-bridge module,an optical isolatorsdrive circuit,etc,where the DSP of TMS320F28335 is used as the controller.When the linear piezoelectric motor working in a macro driven state,the power supply outputs alternating currents with high frequency and high voltage,which drives the linear piezoelectric motor dynamically at an ultrasonic frequency;while working in the micro driven state,the power supply outputs direct currents with high voltage,which drives the linear piezoelectric motor in micro driven statically.Here a prototype of the macro-micro power supply is designed.After a series of experiments on the power supply with and without loads,the results show that the power supply can drive and control the macro micro driven linear piezoelectric motor,and realizes quick and seamless switch between macro and micro drive.In addition,the power supply can drive and control the ultrasonic motor or piezoelectric ceramic micro actuator individually.The power supply achieves the multiple parameters of output signals adjustable simultaneously and exhibits good control characteristics.

A sub-circuit MOSFET model with a wide temperature range including cryogenic temperature

A sub-circuit SPICE model of a MOSFET for low temperature operation is presented.Two resistors are introduced for the freeze-out effect,and the explicit behavioral models are developed for them.The model can be used in a wide temperature range covering both cryogenic temperature and regular temperatures.

Modeling of High-Voltage LDMOS for PDP Driver ICs

A SPICE sub-circuit model is developed for high-voltage LDMOS transistors integrated in PDP driver ICs. The model accounts for intrinsic LDMOS phenomena such as the quasi-saturation effects, voltage-dependent drift resistance, self-heating effects, and Miller capacitance. In contrast to most physical or sub-circuit models, the proposed model not only provides precise simulated results,but also brings a very fast modeling procedure. Furthermore,the model also can be embedded in a commercial SPICE simulator easily. The simulation results using the presented models agree well with the measured ones and the error is less than 5%.

Research on a Multiport Parallel Type Hybrid Circuit Breaker for HVDC Grids:Modeling and Design

This paper proposes a star type multiport hybrid circuit breaker(Star-HCB)topology for protection of multiterminal DC transmission.Reliability and stability of high voltage DC(HVDC)grids are determined by their capabilities to withstand DC-side faults.In order to maintain reliability of HVDC grids,both ends of each line should be equipped with hybrid circuit breakers(HCB).This method will increase expenditure of the HVDC,especially the meshed topology.The n-port Star-HCB consists of ultra-fast mechanical disconnectors,load current switch and only one transferring branch which is formed by improved half-bridge sub-module.Compared with existing traditional hybrid circuit breakers and other multiport hybrid circuit breakers,the proposed topology can realize the same short-circuit blocking goal using fewer components.Detailed mathematical transient process calculation and timedomain simulation of the proposed Star-HCB are given to verify its superiority.

Multiple Operating Mode Analysis of Power Converter based on Graph Theory

Power converters are the typical switched systems which operate based on the alternate switching of the semiconductor switches.The operating mode of power converters consists of several operating stages in one switching period.Each operating stage refers to a sub-circuit or equivalent circuit where different sub-circuits are switched in a fixed order according to the control strategy design.Power converter may operate in different operating modes even with the same control scheme,for example,the DC-DC converter has differing performance under the continuous conduction mode(CCM)and discontinuous conduction mode(DCM).Thus,it is necessary to have a comprehensive understanding of the converter’s characteristics in advance to avoid undesired operation in practice.In this paper,the power converter is considered as a graph made up of several meshes.All sub-circuits in power converter can then be obtained by the mesh combination algorithm,and the operating mode can be constructed by considering the preset switching ON/OFF scheme.Ultimately,the typical waveforms in different modes can be predicted,which is useful to identify abnormal phenomena.Cúk converter is taken as an example to demonstrate the proposed multiple mode analysis method.It is found that there are four kinds of phenomena in addition to the well-known CCM and DCM.Finally,the experimental results are provided and show good agreement with the theoretical analysis.