Patents by Inventor William C. Alexander

William C. Alexander has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9742385
    Abstract: A symmetrically-bidirectional bipolar transistor circuit where the two base contact regions are clamped, through a low-voltage diode and a resistive element, to avoid bringing either emitter junction to forward bias. This avoids bipolar gain in the off state, and thereby avoids reduction of the withstand voltage due to bipolar gain.
    Type: Grant
    Filed: July 18, 2016
    Date of Patent: August 22, 2017
    Assignee: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Patent number: 9678519
    Abstract: Methods and systems for controlling voltage output in power converters between two or more portals, where any or all portals can be DC, single phase AC, or multi-phase AC. The present methods involve determining a reference output voltage VI, measuring the output voltage VE over a power cycle, comparing VI to VE to calculate a delta voltage ?V. ?V can then be multiplied by a scaling parameter k to determine a current command IE. IE can then be used by a current control module in a power converter to control output current. The present methods can be implemented as an algorithm embedded in an FPGA controller connected to the power converter.
    Type: Grant
    Filed: February 17, 2014
    Date of Patent: June 13, 2017
    Assignee: IDEAL POWER, INC.
    Inventor: William C. Alexander
  • Patent number: 9660551
    Abstract: The present application teaches, inter alia, methods and circuits for operating B-TRANs (double-base bidirectional bipolar junction transistors). Base drive circuits provide high-impedance drive to the base contact region on whichever side of the device is (instantaneously) operating as the collector. (B-TRANs, unlike other bipolar junction transistors, are controlled by applied voltage, not applied current.) Control signals operate preferred drive circuits, providing diode-mode turn-on and pre-turnoff operation, and a hard ON state with a low voltage drop (the “transistor-ON” state). In some (not necessarily all) preferred embodiments, a self-synchronizing rectifier circuit provides an adjustable low voltage for the gate drive circuit. Also, in some preferred embodiments, the base drive voltage used to drive the c-base region (on the collector side) is varied while monitoring the base current at that terminal, so that no more base current than necessary is applied.
    Type: Grant
    Filed: November 6, 2015
    Date of Patent: May 23, 2017
    Assignee: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Patent number: 9647553
    Abstract: Methods, systems, circuits, and devices for power-packet-switching power converters using bidirectional bipolar transistors (BTRANs) for switching. Four-terminal three-layer BTRANs provide substantially identical operation in either direction with forward voltages of less than a diode drop. BTRANs are fully symmetric merged double-base bidirectional bipolar opposite-faced devices which operate under conditions of high non-equilibrium carrier concentration, and which can have surprising synergies when used as bidirectional switches for power-packet-switching power converters. BTRANs are driven into a state of high carrier concentration, making the on-state voltage drop very low.
    Type: Grant
    Filed: May 25, 2016
    Date of Patent: May 9, 2017
    Assignee: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Patent number: 9647526
    Abstract: Methods and systems for a startup self-test for bidirectional power converters. Voltage levels across bidirectional switches in a bidirectional power converter can be compared at various points in a circuit to determine whether a given switch is operating correctly.
    Type: Grant
    Filed: February 18, 2014
    Date of Patent: May 9, 2017
    Assignee: IDEAL POWER, INC.
    Inventor: William C. Alexander
  • Patent number: 9647568
    Abstract: Methods and systems for bi-directional multi-port power conversion systems and applications are disclosed. In some sample embodiments, current-modulating power converters can be used to provide conversion between synchronous and asynchronous power. In some sample embodiments, current-modulating power converters can perform power conversion can be performed to and from three-phase AC with an active neutral line. In some sample embodiments, current-modulating power converters can convert between synchronous and asynchronous power and also support three-phase AC with active neutral.
    Type: Grant
    Filed: February 17, 2014
    Date of Patent: May 9, 2017
    Assignee: IDEAL POWER, INC.
    Inventors: Paul Bundschuh, William C. Alexander, Guy Michael Barron, Christopher Cobb, Paul Roush
  • Publication number: 20170126225
    Abstract: The present application teaches, among other innovations, methods and circuits for operating a B-TRAN (double-base bidirectional bipolar junction transistor). A base drive circuit is described which provides high-impedance drive to the base contact region on whichever side of the device is operating as the collector (at a given moment). (The B-TRAN, unlike other bipolar junction transistors, is controlled by applied voltage rather than applied current.) The preferred implementation of the drive circuit is operated by control signals to provide diode-mode turn-on and pre-turnoff operation, as well as a hard ON state with a low voltage drop (the “transistor-ON” state). In some but not necessarily all preferred embodiments, an adjustable low voltage for the gate drive circuit is provided by a self-synchronizing rectifier circuit.
    Type: Application
    Filed: August 10, 2016
    Publication date: May 4, 2017
    Applicant: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Publication number: 20170104478
    Abstract: Methods and systems for operating a double-base bidirectional power bipolar transistor. Two timing phases are used to transition into turn-off: one where each base is shorted to its nearest emitter/collector region, and a second one where negative drive is applied to the emitter-side base to reduce the minority carrier population in the bulk substrate. A diode prevents reverse turn-on while negative base drive is being applied.
    Type: Application
    Filed: September 15, 2016
    Publication date: April 13, 2017
    Applicant: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Patent number: 9614458
    Abstract: Methods and systems for determining maximum power points in photovoltaic inverters. The present application describes unique PV converter topologies including algorithms embedded in controllers. The algorithms can be a variable step size binary search to adjust the input conductance in order to find the conductance that will produce the maximum power out of a PV array. Due to these special topologies, the PV inverter will often not experience sudden shutoffs when typical low voltage cut-off limit is reached since a low-current cut-off limit is also set.
    Type: Grant
    Filed: February 17, 2014
    Date of Patent: April 4, 2017
    Assignee: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Publication number: 20170085179
    Abstract: Methods, systems, circuits, and devices for power-packet-switching power converters using bidirectional bipolar transistors (BTRANs) for switching. Four-terminal three-layer BTRANs provide substantially identical operation in either direction with forward voltages of less than a diode drop. BTRANs are fully symmetric merged double-base bidirectional bipolar opposite-faced devices which operate under conditions of high non-equilibrium carrier concentration, and which can have surprising synergies when used as bidirectional switches for power-packet-switching power converters. BTRANs are driven into a state of high carrier concentration, making the on-state voltage drop very low.
    Type: Application
    Filed: May 25, 2016
    Publication date: March 23, 2017
    Applicant: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Publication number: 20170047922
    Abstract: A symmetrically-bidirectional bipolar transistor circuit where the two base contact regions are clamped, through a low-voltage diode and a resistive element, to avoid bringing either emitter junction to forward bias. This avoids bipolar gain in the off state, and thereby avoids reduction of the withstand voltage due to bipolar gain.
    Type: Application
    Filed: July 18, 2016
    Publication date: February 16, 2017
    Applicant: Ideal Power Inc.
    Inventor: William C. Alexander
  • Patent number: 9520764
    Abstract: Methods and systems for bi-directional multi-port power conversion systems and applications are disclosed. In some sample embodiments, current-modulating power converters can be used to provide conversion between synchronous and asynchronous power. In some sample embodiments, current-modulating power converters can perform power conversion can be performed to and from three-phase AC with an active neutral line. In some sample embodiments, current-modulating power converters can convert between synchronous and asynchronous power and also support three-phase AC with active neutral.
    Type: Grant
    Filed: February 17, 2014
    Date of Patent: December 13, 2016
    Assignee: IDEAL POWER, INC.
    Inventors: Paul Bundschuh, William C. Alexander, Guy Michael Barron, Christopher Cobb, Paul Roush
  • Publication number: 20160351399
    Abstract: Methods and systems for double-sided semiconductor device fabrication. Devices having multiple leads on each surface can be fabricated using a high-temperature-resistant handle wafer and a medium-temperature-resistant handle wafer. Dopants can be introduced on both sides shortly before a single long high-temperature diffusion step diffuses all dopants to approximately equal depths on both sides. All high-temperature processing occurs with no handle wafer or with a high-temperature handle wafer attached. Once a medium-temperature handle wafer is attached, no high-temperature processing steps occur. High temperatures can be considered to be those which can result in damage to the device in the presence of aluminum-based metallizations.
    Type: Application
    Filed: May 25, 2016
    Publication date: December 1, 2016
    Applicant: Ideal Power Inc.
    Inventors: Richard A. Blanchard, William C. Alexander
  • Publication number: 20160344300
    Abstract: The present application teaches configurations in which the multiple-ON-mode bidirectional bipolar switch is used to provide very simple circuit configurations which can—when requirements are not stringent—perform certain electrical conversions which might otherwise require a PPSA (Power Packet Switching Architecture) converter.
    Type: Application
    Filed: May 18, 2016
    Publication date: November 24, 2016
    Applicant: Ideal Power Inc.
    Inventor: William C. Alexander
  • Publication number: 20160322256
    Abstract: Methods and systems for fabricating bidirectional devices on both surfaces of a semiconductor wafer. Separation of the second handle wafer is accomplished by patterning a seal layer to form a grid before the second handle wafer is separated.
    Type: Application
    Filed: February 26, 2016
    Publication date: November 3, 2016
    Inventors: Richard A. Blanchard, William C. Alexander
  • Publication number: 20160285388
    Abstract: Power is inverted using double-base-contact bidirectional bipolar transistors in a three-level-inverter topology. The transistors not only switch to synthesize a PWM approximation of the desired AC waveform, but also have transient phases of diode conduction before each full turn-on or turn-off.
    Type: Application
    Filed: January 22, 2016
    Publication date: September 29, 2016
    Inventor: William C. Alexander
  • Publication number: 20160277022
    Abstract: Methods and systems for active charge control diodes with improved reverse recovery characteristics. An extra control terminal is added on the side of a diode nearest to its p-n junction. The control terminal connects to a control region which extends from the drift region to the cathode surface and which is most preferably separated from the cathode region by an insulated trench. During turn-off, the control terminal is most preferably driven negative relative to the cathode just before reversing the polarity of the applied external voltage.
    Type: Application
    Filed: November 18, 2015
    Publication date: September 22, 2016
    Inventors: William C. Alexander, Richard A. Blanchard
  • Publication number: 20160268405
    Abstract: B-TRAN bipolar power transistor devices and methods, using a drift region which is much thinner than previously proposed double-base bipolar transistors of comparable voltage. This is implemented in a high-bandgap semiconductor material (preferably silicon carbide). Very high breakdown voltage, and fast turn-off, are achieved with very small on-resistance.
    Type: Application
    Filed: January 11, 2016
    Publication date: September 15, 2016
    Inventor: William C. Alexander
  • Patent number: 9444449
    Abstract: The present application teaches, inter alia, methods and circuits for operating a B-TRAN (double-base bidirectional bipolar junction transistor). Exemplary base drive circuits provide high-impedance drive to the base contact region on the side of the device instantaneously operating as the collector. (The B-TRAN is controlled by applied voltage rather than applied current.) Current signals operate preferred implementations of drive circuits to provide diode-mode turn-on and pre-turnoff operation, as well as a hard ON state with low voltage drop (the “transistor-ON” state). In some preferred embodiments, self-synchronizing rectifier circuits provide adjustable low voltage for gate drive circuits. In some preferred embodiments, the base drive voltage used to drive the c-base region (on the collector side) is varied while base current at that terminal is monitored, so no more base current than necessary is applied. This solves the difficult challenge of optimizing base drive in a B-TRAN.
    Type: Grant
    Filed: November 6, 2015
    Date of Patent: September 13, 2016
    Assignee: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Patent number: 9431888
    Abstract: Methods and systems for power conversion. An energy storage capacitor is contained within an H-bridge subcircuit which allows the capacitor to be connected to the link inductor of a Universal Power Converter with reversible polarity. This provides a “pseudo-phase” drive capability which expands the capabilities of the converter to compensate for zero-crossings in a single-phase power supply. Conversion between, e.g., single phase and three phase power is enabled, in either direction, without sacrificing workload performance.
    Type: Grant
    Filed: February 17, 2014
    Date of Patent: August 30, 2016
    Assignee: IDEAL POWER, INC.
    Inventor: William C. Alexander