Search Results - khai ngo

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Aerosolized MagnetoElectric Mechanical Antenna (AMEMA)
Aerosolized MagnetoElectric Mechanical Antenna (AMEMA) is a radical concept for reducing the size of VLF transmitter by five orders of magnitude - without bulk motion. By leveraging the breakthrough's made at Virginia Tech in developing mathematical models for time-variant system, non-resonant radiating structures and tuning electronics, and combin...
Published: 3/30/2017   |   Inventor(s): Khai Ngo, Shashank Priya
Keywords(s):  
Category(s): Electrical, Engineering
Forced Unbalanced Method to Reduce Transient Current Unbalance in Semiconductor Power Switches
Switching power devices, specifically SiC MOSFET, has wider parameter variations (Vth, Rds(on)) due to fabrication process; therefore, when putting several MOSFET dies togther in parallel in a power module, there will be current/power unbalance when they are being used. Several publications have mentioned about using different control techniques to...
Published: 2/6/2017   |   Inventor(s): Zichen Miao, Yincan Mao, Khai Ngo, Chi Ming Wang
Keywords(s):  
Category(s): Electrical, Energy, Engineering, Transportation
Parasitic Inductances Coupling to Reduce Transient Current Unbalance in Semiconductor Power Switches
Switching power devices, specifically SiC MOSFET, has wider parameter variations (Vth, Rds(on)) due to fabrication process: therefore, when putting several MOSFET dies together in parallel in a power module, there will be current/power unbalance when they are being used. Several publications have mentioned about using different control techniques ...
Published: 1/13/2017   |   Inventor(s): Yincan Mao, Zichen Miao, Khai Ngo, Chi Ming Wang
Keywords(s):  
Category(s): Electrical, Energy, Engineering, Transportation
Use Parasitic Inductance Coupling to Eliminate Power Device Switching Operation Reliability Issues Such As Cross-Talk, Self Turn-On, and Self-Sustained Oscillation
The purpose of this invention is to show the new concept of using parasitic inductance coupling to improve SiC MOSFET switching operation reliability to prevent detrimental phenomenon such as crosstalk, self turn-on, and self-sustained oscillation from happening. Conventional methods either slow down the circuit or increase the design complexity. I...
Published: 1/13/2017   |   Inventor(s): Yincan Mao, Zichen Miao, Khai Ngo, Chi Ming Wang
Keywords(s):  
Category(s): Electrical, Energy, Engineering, Transportation
Distributed Kelvin-Source Resistance to Reduce Dynamic Power/Current Imbalance in Paralleled Semiconductor Power Switches
Switching power devices, especially SiC MOSFETs, have wide parameter variations due to fabrication process. When putting several MOSFETs in parallel, there will be current/power unbalance during switching transient. Several publications have mentioned about using different control techniques to actively reduce the unbalance. However, these controls...
Published: 1/13/2017   |   Inventor(s): Yincan Mao, Zichen Miao, Khai Ngo, Chi Ming Wang
Keywords(s):  
Category(s): Electrical, Energy, Engineering, Transportation
Active Compensation of Buck-boost Power Amplifier for Constant Frequency Operation Under Wide-load Variation
The resonant frequency of the buck-boost power amplifier varies with wide-load variation. When the switching frequency of the amplifier is fixed, detrimental current spikes would occur in boost switches. The efficiency would reduce by few percent with possible gate driver erroneous operation. The buck switches normally operates at hard-switching mo...
Published: 12/12/2016   |   Inventor(s): Khai Ngo, Milisav Danilovic
Keywords(s):  
Category(s): Electrical, Engineering
Cooler with EMI-Limiting Inductor
A power switch is mounted on a cooler via isolating dielectric ( such as alumina or aluminum-nitride) that forms a "parasitic" capacitor (referred to herein as C dielectric) measuring tens to hundreds of pico-Farads. As the switch's terminal(s) transitions from one voltage level to another, noise current commonly known as EMI (Electro-Mag...
Published: 7/18/2016   |   Inventor(s): Khai Ngo, Han Cui, Chi Ming Wang
Keywords(s):  
Category(s): Electrical
Converter to Charge Battery from Multiple Sources
Disclosed is a converter that routes power among multiple input/output ports, and one application of the invention is to charge battery from multiple sources.
Published: 4/11/2016   |   Inventor(s): Khai Ngo, Shigeharu Yamagami
Keywords(s):  
Category(s): Electrical, Engineering, Transportation
Drivers with Equalizers for Paralleled Switches
Semiconductor switches are often paralleled to realize a power module with high current rating. They are driven preferably by a single driver that applies the same voltage/current to all switches' input terminals. Some of the switches will take more currents owing to mismatches among such parameters as on-resistances and threshold voltages, and suf...
Published: 2/29/2016   |   Inventor(s): Khai Ngo, Lujie Zhang, Zichen Miao
Keywords(s):  
Category(s): Electrical, Energy, Engineering
Boost Power Amplifier with Improved Bandwidth
“Power amplifier” in this disclosure refers to a switched-mode converter that generates a sinusoidal output at the switching frequency from a dc input. A conventional boost power amplifier contains two matched inductors, each connected between the input source and a grounded switch. Larger inductance would reduce steady-state ripple cur...
Published: 2/8/2016   |   Inventor(s): Khai Ngo, Yincan Mao
Keywords(s):  
Category(s): Electrical
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