Demonstration of High-Voltage SiC VJFET Cascode in a Half-Bridge Inverter

2007 ◽  
Vol 556-557 ◽  
pp. 979-982 ◽  
Author(s):  
Ty McNutt ◽  
John Reichl ◽  
Harold Hearne ◽  
Victor Veliadis ◽  
Megan McCoy ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Steady State ◽  
High Voltage ◽  
Pulse Width ◽  
Low Voltage ◽  
Power Conversion ◽  
Pulse Width Modulated ◽  
Ac Power ◽  
Steady State Current ◽  
Load Resistor

This work utilizes silicon carbide (SiC) vertical JFETs in a cascode configuration to exploit the inherent advantages of SiC and demonstrate the device under application conditions. The all-SiC cascode circuit is made up of a low-voltage normally-off vertical JFET, and high-voltage normally on vertical JFET to form a normally-off cascode switch. In this work, a half-bridge inverter was developed with SiC cascode switches for DC to AC power conversion. The inverter uses high-side and a low-side cascode switches that are Pulse Width Modulated (PWM) from a 500 V bus to produce a 60 Hz sinusoid at the output. An inductor and a capacitor were used to filter the output, while a load resistor was used to model the steady-state current of a motor.

A Phenomenological Study of the Steady-State Current Sheet Speed in a Magnetically Driven Shock Tube

1972 ◽  
Vol 27 (6) ◽  
pp. 948-955
Author(s):  
C. T. Chang
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Steady State ◽  
Current Sheet ◽  
High Voltage ◽  
Electrode Surface ◽  
Phenomenological Study ◽  
Low Voltage ◽  
Basic Assumptions ◽  
Steady State Current

Abstract The discrepancy between the measured steady-state speed of the current sheet and the theoretically predicted value is examined through a detailed analytical and experimental study of the basic assumptions used in the model. It is found phenomenologicaly that the observed deviation at dis-charge conditions of low voltage and high pressure could be attributed mainly to the spreading of the current-carrying region in time. The deviation occurring at discharge conditions of high voltage and low pressure could be attributed to the possible presence of an ion drag caused by the interaction between the plasma and the electrode surface.

scholarly journals High Step-up Coupled Inductor Inverters Based on qSBIs

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3032 ◽  
Author(s):  
Hongchen Liu ◽  
Xi Su ◽  
Junxiong Wang
Keyword(s):  
Steady State ◽  
High Voltage ◽  
Low Voltage ◽  
Duty Ratio ◽  
Voltage Gain ◽  
Passive Components ◽  
Steady State Analysis ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
Working Principle

In this paper, two types of high step-up coupled inductor inverters based on qSBIs (quasi- switched boost inverters) are proposed. By applying the coupled inductor to the qSBIs, the voltage gain of the proposed inverter is regulated by turn ratio and duty ratio. Thus, a high voltage gain can be achieved without the circuits operating at the extreme duty cycle by choosing a suitable turn ratio of the coupled inductor. In addition, the proposed circuits have the characteristics of continuous input current and low voltage stress across the passive components. A boost unit can be added to the proposed inverters for further improvement of the voltage gain. In this paper, the working principle, steady state analysis, and the comparisons of the proposed inverter with other impedance-source inverters are described. A 200 W prototype was created and the experimental results confirm the correctness of the analysis in this paper.

Transient Two-Phase Flow Patterns by Application of a High Voltage Pulse Width Modulated Signal and the Effect on Condensation Heat Transfer

2010 ◽  
Author(s):  
K. Ng ◽  
C. Y. Ching ◽  
J. S. Cotton
Keyword(s):  
Heat Transfer ◽  
Flow Pattern ◽  
Electric Fields ◽  
High Voltage ◽  
Mass Flux ◽  
Pulse Width ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Pulse Width Modulated

The objectives of this study are (i) to determine the transient phase redistributions of a two-phase flow in a smooth horizontal annular channel by applying high voltage pulses to induce electric fields and (ii) to quantify the resultant changes in the condensation heat transfer. The experiments were performed using refrigerant R-134a flowing in a tube that was cooled on the outside by a counter-current flow of water. The electric fields are established by applying high voltage to a concentric rod electrode inside a grounded tube. The effect of the electrohydrodynamic (EHD) forces on the changes to the initial stratified/stratified wavy flow pattern was visualized using a high speed camera. The EHD effect results in the redistribution of the liquid-vapour phase within the channel and unique flow structures, such as twisted liquid cones and entrained droplets, are observed. These structures only appear during the initial application of EHD and are absent in the steady state flow pattern. Experiments were performed using a 8kV pulse width modulated (PWM) signal with duty cycles ranging from 0–100% to evaluate the heat transfer and pressure drop characteristics of the transient EHD flow patterns. The resultant heat transfer increased with the duty cycle to approximately 2.7-fold at a low mass flux (45–55kg/m2s) and 1.2-fold at a high mass flux (110kg/m2s). The enhancement was higher as the pulse width was increased.

Variable Resistance Type Energy Regenerative Damper Using Pulse Width Modulated Step-up Chopper

2001 ◽  
Vol 124 (1) ◽  
pp. 110-115 ◽  
Author(s):  
Sang-Soo Kim ◽  
Yohji Okada
Keyword(s):  
Pulse Width ◽  
High Speed ◽  
Low Voltage ◽  
Dead Zone ◽  
Control Technique ◽  
Vibration Energy ◽  
Low Speed ◽  
Pulse Width Modulated ◽  
Active Mass Damper ◽  
A New Technique

This paper describes a new technique for improving the damping property and efficiency of an energy regenerative damper. It is intended for a linear DC motor type vibration damper to regenerate vibration energy efficiently. Normally a regenerative damper can regenerate vibration energy only at high speed motion. For low speed motion, the damper has nonlinear characteristics with dead zone and cannot regenerate energy. In order to overcome this problem, a step-up chopper is introduced between the actuator and the charging circuit. The energy is regenerated from low speed and low voltage actuator to high voltage charging circuit. This paper also proposes a new control technique to the step-up chopper by using pulse width modulated signals. The damper can change its damping coefficient and the energy can be regenerated more efficiently. The proposed damper is applied to an active mass damper system. A simple experimental setup is used to validate the proposed technique. The results show an increase in performance and energy regeneration as compared to the previously proposed regenerative damper.

Testing of low-voltage motor turn insulation intended for pulse-width modulated applications

2000 ◽  
Vol 7 (6) ◽  
pp. 783-789 ◽  
Author(s):  
N. Kandev ◽  
P. Castelan ◽  
T. Lebey ◽  
N. Amyot ◽  
C. Hudon
Keyword(s):  
Pulse Width ◽  
Low Voltage ◽  
Pulse Width Modulated ◽  
Turn Insulation
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