Virginia Tech Patents

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These United States Patents were originally assigned to Virginia Tech.

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  • Line frequency commutated voltage source converters for multiphase modular multilevel converters
    (2022-11-29)
    Aspects are described for line frequency commutated voltage source converters for multiphase modular multilevel converters. A voltage source converter (VSC) capacitor voltage of a multiphase VSC of a multiphase power converter can be identified. The multiphase VSC can include a half-bridge circuit for each phase of the multiphase power converter. A circuit parameter can be identified and utilized to determine an arm voltage of an arm of a branch of the multiphase converter. Switch control signals can be generated to insert or bypass the VSC capacitor for the arm of the branch of the multiphase converter device, based at least in part on a comparison between the arm voltage and the VSC capacitor voltage.
  • Fog Harvester Having a Vertical Wire Array and Uses Thereof
    (United States Patent and Trademark Office, 2022-10-11)
    Described herein are fog harvesters having a vertical wire array and systems thereof. The fog harvesters described herein can be used to harvest liquid from the air, such as from fog. The fog harvesters can, in some aspects, have improved performance in one or more aspects as compared to fog harvesters having a mesh design.
  • Three-Phase, Three-Level Inverters and Methods for Performing Soft Switching with Phase Synchronization
    Burgos, Rolando; Haryani, Nidhi; Boroyevich, Dushan; Ohn, Sungjae (2021-01-05)
    A three-phase, N-level inverter and method are disclosed. A circuit topology of the inverter comprises first, second and third sets of switches and first, second and third inductors. Each switch comprises at least first, second and third terminals, the first terminals being control terminals. The first terminals of the first, second and third inductors are electrically coupled to the first, second and third sets of switches, respectively. A current controller performs a control algorithm that causes it to output first, second and third sets of gating signals to the control terminals of the switches of the first, second and third sets of switches, respectively, to cause them to be placed in an on state or an off state in a particular sequence to perform zero voltage switching while maintaining synchronization of the three phases of the three-phase, N-level inverter.
  • Planar Bridging-Droplet Thermal Diode
    Boreyko, Jonathan B.; Edalatpour, Mojtaba; Murphy, Kevin; Mukherjee, Ranit (Innovators Legal, 2021-12-30)
    This disclosure provides a thermal diode including a first plate having a first surface defining a wick structure. The thermal diode can include a second plate having a smooth surface facing the wick structure, the smooth surface and the wick structure defining a chamber for accommodating a phase-change liquid. The thermal diode also can include a separator positioned between the first plate and the second plate to separate the wick structure from the smooth surface by a gap that is less than a capillary length of the phase-change liquid.
  • Liquid crystalline polyester compositions and methods
    (United States Patent and Trademark Office, 2020-09-01)
    Liquid crystalline hydroquinone-3,4′-biphenyl dicarboxylate polyesters, and methods of making them. The polyesters may be melt processed at a temperature below the thermal decomposition temperature and the isotropic temperature, and may form a liquid crystalline glass phase. The polyesters may be formed by polycondensation of hydroquinone or a hydroquinone derivative with 3,4′-biphenyl dicarboxylic acid.
  • Energy-efficient extraction of acid gas from flue gases
    (United States Patent and Trademark Office, 2020-08-25)
    An energy-efficient method of removing carbon dioxide, hydrogen sulfide, and other acid gases from a stream of flue gases. The flue stream is contacted with a predetermined sorbent system to remove acid gases from the flue stream. The acid gas-rich sorbent is then heated to desorb the acid gas for capture and regenerate the sorbent. Heat exchangers and heat pumps are used to reduce utility steam and/or cooling water consumption.
  • Device and method for electroporation based treatment of stenosis of a tubular body part
    (United States Patent and Trademark Office, 2020-07-07)
    The present invention relates to medical devices and methods for treating a lesion such as a vascular stenosis using non-thermal irreversible electroporation (NTIRE). Embodiments of the present invention provide a balloon catheter type NTIRE device for treating a target lesion comprising a plurality of electrodes positioned along the balloon that are electrically independent from each other so as to be individually selectable in order to more precisely treat an asymmetrical lesion in which the lesion extends only partially around the vessel.
  • Circulating current injection control
    (United States Patent and Trademark Office, 2018-12-11)
    In one example, a power converter includes a modular multilevel converter (MMC) electrically coupled between a first power system and a second power system. The MMC includes an arrangement of switching submodules, and the switching submodules include an arrangement of switching power transistors and capacitors. The MMC also includes a controller configured to inject a common mode frequency signal into a circulating current control loop. The circulating current control loop is relied upon to reduce at least one low frequency component in power used for charging the capacitors in the switching submodules. By injecting the common mode frequency signal into the circulating current control loop, the switching submodules can be switched at higher frequencies, the capacitances of the capacitors in the MMC can be reduced, and the power density of the MMC can be increased.
  • Polybenzimidazoles and methods of making and using thereof
    (United States Patent and Trademark Office, 2019-01-29)
    Disclosed are polybenzimidazoles containing sulfonyl groups. The polymers can be synthesized in Eaton's reagent from 3,3′,4,4′-tetraaminodiphenylsulfone, which itself can be synthesized from 4,4′-dichlorodiphenylsulfone. Methods of synthesizing the polymers are disclosed. The disclosed polymers can be used for high temperature H2/CO2 separation membranes and other uses.
  • Method for jointly adapting an OFDM waveform and the demodulator for interference mitigation and harsh channels
    (United States Patent and Trademark Office, 2019-02-05)
    The present invention provides a method and system for a processing multicarrier signal to create a spectral correlation across multiple antennas. The system includes at least one transmitter adapted to create a plurality of symbols, each symbol representing one or more bits from a plurality of bitstreams. The transmitter creates a plurality of repetition patterns, each pattern containing a copy of the symbols and each repetition pattern comprising a combination of symbols that varies in time, frequency and space. The repetition patterns are transmitted over and received by one or more separate antennas where a receiver demodulates the repetition patterns and linearly combines each repeated symbols across time, frequency and space to estimate said transmitted symbol.
  • Method and apparatus for balancing current and power
    (United States Patent and Trademark Office, 2019-01-22)
    Aspects of the disclosure provide a power circuit that includes a first switch circuit in parallel with a second switch circuit. The first switch circuit and the second switch circuit are coupled to a first control node, a second control node, a first power node and a second power node via interconnections. The power circuit receives a control signal between the first control node and the second control node to control a current flowing from the first power node to the second power node through the first switch circuit and the second switch circuit. At least one of a first source terminal of the first switch circuit and a second source terminal of the second switch circuit is coupled to the second control node with a resistive element having a specific resistance.
  • Fiber array for optical imaging and therapeutics
    (United States Patent and Trademark Office, 2019-03-05)
    The present invention relates to the field of optical imaging and therapeutics. More particularly, embodiments of the present invention provide minimally-invasive Fiberoptic Microneedle Devices (FMDs) for light-based therapeutics, which physically penetrate tissue and deliver light directly into the target area below the skin surface. Embodiments of the invention enable depth-selective and deep photothermal therapeutics and include methods of treating cancer, methods of re-shaping or removing adipose tissue, and methods of delivering drugs or co-delivering drugs and energy to selected tissue.
  • Non-linear droop control
    (United States Patent and Trademark Office, 2020-09-08)
    Aspects of non-linear droop control are described herein. In one embodiment, a system includes a first power converter or source configured to provide power to a bus, a second power converter or source configured to provide power to the bus, and a load electrically coupled to the bus. The system also includes a controller configured to adjust a droop resistance associated with the first power source according to a continuous non-linear function based on an amount of current supplied to the load by the first power source. The system can also include a second controller configured to adjust a droop resistance associated with the second power source according to the continuous non-linear function (or another continuous non-linear function). The use of the continuous non-linear functions achieves tighter voltage regulation particularly at lower loads and better load sharing at higher loads.
  • Learning and deployment of adaptive wireless communications
    (United States Patent and Trademark Office, 2019-02-26)
    Methods, systems, and apparatus, including computer programs encoded on computer storage media, for training and deploying machine-learned communication over radio frequency (RF) channels. One of the methods includes: determining first information; using an encoder machine-learning network to process the first information and generate a first RF signal for transmission through a communication channel; determining a second RF signal that represents the first RF signal having been altered by transmission through the communication channel; using a decoder machine-learning network to process the second RF signal and generate second information as a reconstruction of the first information; calculating a measure of distance between the second information and the first information; and updating at least one of the encoder machine-learning network or the decoder machine-learning network based on the measure of distance between the second information and the first information.
  • Low-temperature co-firing of multilayer textured piezoelectric ceramics with inner electrodes
    (United States Patent and Trademark Office, 2019-03-05)
    Textured PMN-PZT fabricated by templated grain growth (TGG) method has a piezoelectric coefficient (d) of 3 to 5 times that of its random counterpart. By combining this TGG method with low-temperature co-firing ceramics (LTCC) techniques, co-fired multilayer textured piezoelectric ceramic materials with inner electrodes were produced at a temperature as low as 925° C., which silver could be used. Trilayer PMN-PZT ceramics prepared by this method show a strain increase of 2.5 times, a driving voltage decrease of 3 times, and an equivalent piezoelectric coefficient (d*) improvement of 10 to 15 times that of conventional random ceramic counterparts. Further, a co-fired magnetostrictive/piezoelectric/magnetostrictive laminate structure with silver inner electrode was also synthesized. The integration of textured piezoelectric microstructure with the cost-effective low-temperature co-fired layered structure achieves strong magnetoelectric coupling. These new materials have promising applications including as actuators, ultrasonic transducers, and use in energy harvesters.
  • Multiphase coupled and integrated inductors with printed circuit board (PBC) windings for power factor correction (PFC) converters
    (United States Patent and Trademark Office, 2019-02-26)
    A power factor correction (PFC) power converter, particularly of a multiphase totem-pole or other topology presenting a switching bridge that can potentially provide bi-directional power transfer control, reduces a nominal switching frequency and achieves zero voltage switching over an increased portion of a half line cycle by providing positive or inverse coupling of inductors in an inductor structure that can be formed of a multi-layer printed circuit board such that at least three different inductances are presented during each half line cycle period; allowing increased switching frequency and simplifying EMI filtering arrangements. Parasitic capacitances can be balanced with additional coupled windings to reduce differential mode and common mode noise. The PFC power converter is particularly applicable to provide bi-directional power control from an on-board battery charger in an electrically powered vehicle.
  • Transmitter for transmitting a high-rate data transmission through direct excitation
    (United States Patent and Trademark Office, 2019-02-26)
    One aspect is a circuit for tuning a resonance frequency of an electrically small antenna and directly exciting the electrically small antenna. The circuit includes a first source configured for providing a constant voltage. The circuit also includes an antenna and a switched capacitor configured for being alternatively alternately coupled to the first source to be charged thereby and to the antenna for exciting the antenna. Another aspect is a transmitter for transmitting a wireless signal using an antenna without using a variable voltage source to excite the antenna. The transmitter includes a first source configured for providing a constant voltage. The transmitter further includes an antenna and a switched capacitor configured for being alternately coupled to the first source to be charged thereby and to the antenna for exciting the antenna and for tuning a resonance frequency of the antenna.
  • System and method for ablating a tissue site by electroporation with real-time monitoring of treatment progress
    (United States Patent and Trademark Office, 2019-03-26)
    A medical system for ablating a tissue site with real-time monitoring during an electroporation treatment procedure. A pulse generator generates a pre-treatment (PT) test signal having a frequency of at least 1 MHz prior to the treatment procedure and intra-treatment (IT) test signals during the treatment procedure. A treatment control module determines impedance values from the PT test signal and IT test signals and determines a progress of electroporation and an end point of treatment in real-time based on the determined impedance values while the treatment progresses.
  • Bibenzoate copolyesters and methods to produce them
    (United States Patent and Trademark Office, 2020-09-08)
    Bibenzoate copolyesters are based on (4,4′-biphenyl dicarboxylic acid-co-3,4′-biphenyl dicarboxylic acid) as the diacid component, and on an alicyclic diol compound such as 1,4-cyclohexanedimethanol as a portion of the diol component. Copolyesters are based on 4,4′-biphenyl dicarboxylic acid, and/or 3,4′-biphenyl dicarboxylic acid as the diacid component and may include a multifunctional acid. Copolymers may optionally base an essentially amorphous morphology, high glass transition temperature, high elongation at break, and/or high melting temperature. A method to make the copolymers controls the characteristics of the copolyester selected from one or a combination of amorphous morphology or degree of crystallinity, Tg, Tm, tensile modulus, flexural modulus, elongation at break, and so on, by selecting the proportions of the 4,4′-biphenyl dicarboxylic acid or ester producing equivalent thereof, 3,4′-biphenyl dicarboxylic acid or ester producing equivalent thereof, and/or the proportion of the 1,4-cyclohexanedimethanol in the diol component.
  • Optimal battery current waveform for bidirectional PHEV battery charger
    (United States Patent and Trademark Office, 2019-04-02)
    The present invention provides a battery charger and battery charging method controlled with a charging waveform input of an AC-DC switching circuit to a DC link and a DC-DC stage converter for outputting a regulated DC voltage. The method determining the charging waveform comprising the steps of selecting a Pulse Width Modulation (PWM) zero-off charging waveform signal input to the AC-DC switching circuit and calculating a ripple power at the DC link based on the signal input power and output power of the regulated DC voltage output.