Thyristor Type Patents (Class 363/160)
  • Patent number: 10581336
    Abstract: An energy control circuit is provided. The energy control circuit includes an input circuit; an output circuit; an energy storage circuit coupled between the input circuit and the output circuit; and a controller coupled to the input circuit and output circuit for controlling an amount of energy stored in the energy storage circuit and for controlling a waveform generated by the output circuit using energy stored in the energy storage circuit.
    Type: Grant
    Filed: December 21, 2018
    Date of Patent: March 3, 2020
    Assignee: Enphase Energy, Inc.
    Inventors: Martin Fornage, Damon Charles Cayford
  • Patent number: 10250120
    Abstract: Power conversion devices with control algorithms that can solve the double frequency harmonic problem are provided, as are techniques for controlling power converters when the instantaneous values of input and output power are not the same.
    Type: Grant
    Filed: May 18, 2017
    Date of Patent: April 2, 2019
    Assignee: Northeastern University
    Inventor: Mahshid Amirabadi
  • Patent number: 10177672
    Abstract: A power system can include a first tap changer for a first regulated transformer, where the first tap changer has a plurality of first positions. The power system can also include a second tap changer for a second regulated transformer, where the second tap changer has a plurality of second positions. The power system can further include at least one first instrument transformer coupled to the first regulated transformer. The power system can also include at least one second instrument transformer coupled to the second regulated transformer. The power system can further include a controller coupled to the at least one first instrument transformer and the at least one second instrument transformer, where the controller adjusts the first tap changer to a first adjusted position among the first positions based on the first measurements of the first regulated transformer and the second measurements of the second regulated transformer.
    Type: Grant
    Filed: April 6, 2017
    Date of Patent: January 8, 2019
    Inventors: Daniel Joseph Daley, Daniel Michael Sauer, Fred Joseph Rapant
  • Patent number: 9543853
    Abstract: The AC portion of the input of the ultra-sparse partial resonant power converter contains three pairs of forward-conducting-bidirectional-blocking switches connected in a first direction, and two pairs of forward-conducting-forward-blocking devices connected in a second direction to the three pairs of forward-conducting-bidirectional-blocking switches. The second direction is opposite to the first direction. The AC portion of the output of the ultra-sparse partial resonant power converter contains three pairs of forward-conducting-bidirectional-blocking switches connected in a first direction, and two pairs of forward-conducting-reverse-blocking devices connected in a second direction to the three pairs of forward-conducting-bidirectional-blocking switches. The forward-conducting-reverse-blocking devices can be switches or diodes.
    Type: Grant
    Filed: June 4, 2014
    Date of Patent: January 10, 2017
    Assignee: The Texas A&M University System
    Inventors: Hamid A. Tollyat, Mahshid Amirabadi
  • Patent number: 9479082
    Abstract: A method and apparatus for providing multi-phase power. In one embodiment, the apparatus comprises a cycloconverter controller for determining a charge ratio based on a reference waveform; and a cycloconverter, coupled to the cycloconverter controller and to a multi-phase AC line, for selectively coupling an alternating current to each line of the multi-phase AC line based on the charge ratio.
    Type: Grant
    Filed: January 3, 2012
    Date of Patent: October 25, 2016
    Assignee: Enphase Energy, Inc.
    Inventors: Martin Fornage, Donald Richard Zimmanck
  • Patent number: 9276486
    Abstract: A matrix converter includes a power converter, a command generator, and a commutation controller. The power converter includes bidirectional switches each having a conducting direction controllable by switching elements. The bidirectional switches are disposed between input terminals coupled to phases of an AC power source and output terminals coupled to phases of a load. The command generator generates a control command based on a voltage command specifying a pulse width of pulse width modulation control. The commutation controller controls the switching elements by a commutation method based on the control command so as to perform commutation control. The command generator includes a corrector to, when an error in an output voltage is caused by the commutation control, correct the pulse width specified in the voltage command in generating the control command to reduce the error in the output voltage.
    Type: Grant
    Filed: November 13, 2014
    Date of Patent: March 1, 2016
    Inventors: Akira Yamazaki, Joji Ebisu
  • Patent number: 9219424
    Abstract: A matrix converter according to an embodiment includes a voltage command corrector and a drive signal generator. The voltage command corrector corrects the magnitude of an output voltage command on the basis of amplitude variations of an input current from an AC power supply to a power converter, the amplitude variations being caused by a ripple component of the input current. The drive signal generator generates drive signals that turn ON/OFF a plurality of bidirectional switches on the basis of the output voltage command corrected by the voltage command corrector.
    Type: Grant
    Filed: June 12, 2014
    Date of Patent: December 22, 2015
    Inventors: Kentaro Inomata, Hidenori Hara, Takahiro Uchino
  • Publication number: 20140168848
    Abstract: The disclosed technology describes methods and apparatus to convert and control power provided to a precipitator. An example embodiment of the disclosed technology includes a method for providing power to a device. The method includes receiving a first silicon controlled rectifier (SCR) signal and a second SCR signal from a controller device, generating a demand signal by the controller device based on a comparison of the first and second SCR signals, transmitting the demand signal to a power converter device, converting a first power signal from a first base frequency to a second power signal at a second base frequency, wherein the first base frequency is in the range of approximately 50 Hz to approximately 60 Hz and wherein the second base frequency is controlled in the range of approximately 100 Hz to approximately 1000 Hz, and switching the second power signal to the controller device.
    Type: Application
    Filed: December 14, 2012
    Publication date: June 19, 2014
    Applicant: Redkoh Industries, Inc.
    Inventors: Paul Ford, John Jannone, Neil Flynn, Hank Del Gatto
  • Patent number: 8526208
    Abstract: An electrical circuit, in particular a circuit used for generating electric power, wherein this circuit comprises a generator with n phases, a converter and a transformer to which a p-phase load can be connected. The converter comprises m partial converters, each of the partial converters is composed of p units and each of these units is provided with n/m switching circuits. The switching circuits of the individual units are connected symmetrical to the generator.
    Type: Grant
    Filed: October 9, 2009
    Date of Patent: September 3, 2013
    Assignee: Converteam Technology Ltd.
    Inventors: Georg Moehlenkamp, Reinhard Wagnitz
  • Patent number: 8289735
    Abstract: In general, in one aspect, the invention relates to a method for delivering a controlled voltage. The method involves, during a first electric pulse delivered to a primary transformer, holding a first switching section open to isolate the controlled voltage, where the first electric pulse creates a first magnetic flux in a core of the primary transformer, and where the first magnetic flux generates a direct current (DC) magnetizing current. The method further involves receiving the controlled voltage from a voltage source using the DC magnetizing current at a first switching section, and upon termination of the first electric pulse, closing the first switching section to deliver the controlled voltage to the primary transformer.
    Type: Grant
    Filed: July 7, 2011
    Date of Patent: October 16, 2012
    Assignee: Varentec LLC
    Inventors: Rudolf Limpaecher, Alex Wilhelm Limpaecher
  • Patent number: 8045354
    Abstract: A method for operating a matrix converter to convert n phases of a generator into alternating voltage with nr (nr<n) phases of a load connected to a network includes the steps of alternatingly connecting the nr phases of the load using a plurality of controllable bi-directional switches disposed in an (n×nr) matrix, wherein nr phases of the generator are always connected with the load and (n?nr) phases of the generator are not connected with the load, and controlling the switching of a phase k of the generator at a time t to a phase c of the grid, using a periodical, continuous, segmented function k(t). The function k(t) defines a broken line having a plurality of segments, wherein each segment i is defined by a starting time ti and a pulsation ?i, and the value of the function k(t) is rounded to the closest integer value.
    Type: Grant
    Filed: March 28, 2008
    Date of Patent: October 25, 2011
    Assignee: Alstom Technology Ltd
    Inventor: Alain Lacaze
  • Publication number: 20100284208
    Abstract: A power-conversion control system includes an inverter, a cycloconverter, and a sliding mode controller. The inverter is operable to receive a DC voltage input and produce a first AC voltage output having a first frequency. The cycloconverter has a plurality of bidirectional switches, and is operable to receive the first AC voltage and to synthesize a second AC voltage having a second frequency that is lower than the first frequency. The sliding mode controller is operable to provide a control signal to command the plurality of bidirectional switches to turn OFF and ON when the first AC voltage is at a zero crossing condition. The sliding mode controller is also operable to selectively adjust the frequency and amplitude of the second AC voltage.
    Type: Application
    Filed: May 5, 2009
    Publication date: November 11, 2010
    Inventors: Vietson M. Nguyen, Gregory I. Rozman, Sastry V. Vedula
  • Publication number: 20090279338
    Abstract: In a cycloconverter generator, there are provided, q number of power circuits that supply rectified DC power of a DC power supply unit as operating power to the p (p>q) number of thyristors, and r (p>r) number of thyristor drive circuits that are connected to the q number of the power circuits and drive the p number of the thyristors, wherein the r number of the thyristors drive circuits are individually used to drive in common ones among the p number of the thyristors whose operation is unaffected even if driven at the same timing such that the number r of the drive circuits is made smaller than the number p of the thyristors, thereby enabling to simplify circuit configuration.
    Type: Application
    Filed: May 6, 2009
    Publication date: November 12, 2009
    Applicant: HONDA MOTOR CO., LTD
    Inventors: Toshinori INAGAWA, Shinsaku Nakayama, Yoshinori Masubuchi
  • Patent number: 7187569
    Abstract: An apparatus for generating electronic signals for application in subsea electromagnetic exploration. A surface generated high-voltage low-current source signal stabilized at a first frequency is supplied to a deep-tow vehicle (18) via an umbilical cable (16). The high-voltage low-current signal is transformed at the deep-tow vehicle to a high-current low-voltage a.c. signal by a transformer (52) within a cycloconverter (30). A semiconductor relay bridge (104) provides switchable rectification of the high-current low-voltage a.c. signal to provide a quasi-square wave at a second frequency, lower than the first frequency, for supply to a transmitting antenna (22) towed by the deep-tow vehicle. The times of the rectification switching are dependent on zero crossings of the high-current low-voltage a.c. signal. Allowable rectification switching times may be gated to occur only within pre-determined time windows to avoid noise-induced zero-crossing switching.
    Type: Grant
    Filed: October 2, 2002
    Date of Patent: March 6, 2007
    Assignee: University of Southampton
    Inventors: Martin C. Sinha, Lucy M. MacGregor
  • Patent number: 6992907
    Abstract: The present invention relates a waveform transformation method and apparatus. It uses multilevel transformation module in series, and the output voltages of power modules at all levels are superposed to get the total output voltage, whereas each power transformation module realizes AC-to-AC direct conversion. The deviation between the output? voltage and setting reference voltage at any time point is made as small as possible by selecting different transformation modules as current working circuit and selecting output voltage waveform of the each different transformation modules. The invention includes outputting n groups of electrical insulating AC and n transfonnation modules connected with AC. The wave transformation method and device of present invention eliminates the intermediate DC stage, so that the circuit is greatly simplified, the cost is reduced obviously and improve working efficiency. It makes voltage and current harmonics to be reduced and obtains higher power factor.
    Type: Grant
    Filed: December 5, 2001
    Date of Patent: January 31, 2006
    Inventor: Dongsheng Zhang
  • Patent number: 6654261
    Abstract: The invention in the simplest form is a power conditioning and inverting system for improved and efficient power generation. In particular, the present invention is a modulated dc link scheme that dramatically reduces the switching frequency ripple across the PWM output filter inductor and provides cost, size, and weight reductions, as well as efficiency enhancements. In a preferred embodiment of the present invention, the DC-DC converter control takes a feedback signal proportional to the inverter output voltage. This feedback is “summed” into the primary DC-DC volts command thereby causing the dc bus/link voltage to vary at a multiple of the output fundamental frequency causing the DC link to become a signal at a fundamental frequency voltage with a dc offset. The tooth modulator DC supply tracks the AC output voltage, reducing the difference between the applied DC volts and the AC output volts, thereby reducing inductor core losses.
    Type: Grant
    Filed: October 29, 2001
    Date of Patent: November 25, 2003
    Assignee: Youtility, INC
    Inventors: Richard Shaun Welches, Richard E Griessel, Peter Beckedahl, Karl Bond
  • Patent number: 6636693
    Abstract: A regenerative converter for a DC motor (55) having an armature (A, B) and a field (57), comprises a conventional three-phase matrix converter (6) including a three-phase bridge (7), the output of two phases being connected (52, 53) across the armature of the motor, the third phase being connected (58) to one end (I) of the DC motor field (57). The other end (K) of the DC motor field (57) is connected (59a) through a plurality of diodes (61-63) to respective phases of the input power.
    Type: Grant
    Filed: July 27, 2001
    Date of Patent: October 21, 2003
    Assignee: Otis Elevator Company
    Inventor: Vladimir Blasko
  • Patent number: 6492788
    Abstract: A permanent magnet synchronous motor is controlled using d-axis current and q-axis current along with respective d-current and q-current feedback loops. The speed and position of the motor are determined by injecting a first signal into the d-axis current and observing the response in the q-current feedback loop. Part of the q-current feedback signal is demodulated with a second signal which is 90 degrees out of phase from the first signal. The demodulated signal is preferably sent through a low pass filter before being received by an observer controller. The observer controller outputs a position estimate which is used to modify the d-current feedback signal and a speed estimate which is used to modify the q-axis current.
    Type: Grant
    Filed: November 10, 2000
    Date of Patent: December 10, 2002
    Assignee: Otis Elevator Company
    Inventors: Ismail Agirman, Aleksandar M. Stankovic, Chris Czerwinski, Ed Piedra
  • Patent number: 5990657
    Abstract: An inverter system providing both an improvement in the voltage utilization factor and a reduction in the switching loss uses a two-phase switching method. In the inverter system, an .alpha.-axis voltage command value; v.sub..alpha.r and a .beta.-axis voltage command value v.sub..beta.r are input to a stop phase selection means. Six sections are judged based on the values v.sub..alpha.r and v.sub..beta.r to select phases for which it is allowable to stop pulse width modulation control in a two-phase switching method. Then, a phase having the largest absolute value of current is selected among the phases for which it is allowable to stop pulse width modulation control using a U-phase current i.sub.u and a V-phase current i.sub.v. This information is a control mode S. Based on these, two-phase switching calculations are performed by a dead-time compensation calculation means and a pulse width modulation generating means. By doing so, the switching loss can be reduced.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: November 23, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Ryoso Masaki, Yuusuke Takamoto, Satoru Kaneko, Fumio Tajima, Hiroshi Katada
  • Patent number: 5949672
    Abstract: A three-phase matrix converter for converting AC voltages of predetermined amplitude and frequency into AC voltages of any amplitude and frequency and a method for operating the same, include four-segment switches as main switches which are combined into three switch groups. A resonance capacitance is connected in parallel with each main switch, or an output capacitance of power semiconductors of the main switches acts as a resonance capacitance. An auxiliary commutation device which is provided between three-phase output connections of each switch group has an auxiliary switch constructed as a four-segment switch and a resonance inductance connected in series therewith.
    Type: Grant
    Filed: September 29, 1997
    Date of Patent: September 7, 1999
    Assignee: ABB Patent GmbH
    Inventor: Steffen Bernet
  • Patent number: 5764499
    Abstract: To improve operation when there are dynamic load requirements with a direct a.c. converter with a load connected to it in open circuit, the direct a.c. converter is controlled briefly such that the voltage vector resulting from the geometric sum of the phase voltages is increased while the phase relation remains the same.
    Type: Grant
    Filed: March 27, 1997
    Date of Patent: June 9, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventors: Rolf-Dieter Klug, Hans-Peter Timmert
  • Patent number: 5594636
    Abstract: A method and apparatus for AC-to-AC power conversion wherein commutation from one switch in a switching group to a second switch is effected while both switches are enabled simultaneously without causing a short circuit between the phase input lines associated with each respective switch. Each switch in a switching group is bidirectional and polarity-controlled, and may be selectively enabled to conduct only negative-polarity or positive-polarity current, or may be disabled. An overvoltage clamping circuit is also provided with each switch. A switch gating control circuit is employed to provide selective operation of the switches in a particular switch group.
    Type: Grant
    Filed: June 29, 1994
    Date of Patent: January 14, 1997
    Assignee: Northrop Grumman Corporation
    Inventor: Colin D. Schauder
  • Patent number: 5402054
    Abstract: A method for controlling the speed of an AC machine (12) is described.The AC machine (12) receives three output phases (A,B,C) supplied from a cycloconverter (10) which is connected to an input supply (R,Y,B) of frequency f.sub.1. The cycloconverter (10) is caused to operate in three modes under control of a microprocessor (25).The first mode supplies the AC machine (12) in the frequency range 0 to f.sub.0, by conventional cycloconverting to generate a near continuum of frequencies.The second mode operates the cycloconverter (10) to synthesize a number of frequency steps in the frequency range f.sub.0 to f.sub.1 from the input supply (R,Y,B) and provides speed control of the AC machine (12) by phase control of the output voltage (A,B,C) between each frequency step.The third mode operates the cyclonverter (10) to be transparent, such that the input frequency f.sub.1 is effectively directly supplied to the AC machine (12) without speed regulation being applied.
    Type: Grant
    Filed: August 16, 1993
    Date of Patent: March 28, 1995
    Assignee: Boral Johns Perry Industries Pty. Ltd.
    Inventor: Gregory P. Eckersley
  • Patent number: 5376877
    Abstract: An engine-driven generator includes an internal combustion engine, a permanent magnet alternator and an AC to AC converter. The output frequency and voltage of the permanent magnet alternator are largely dependent on engine speed and the alternator load. The AC to AC converter converts the speed-dependent alternating current developed by the alternator to another alternating current whose frequency and voltage are largely independent of engine speed. Voltage regulation is provided by varying the engine speed in accordance with the load current. Frequency regulation is provided by frequency dividing the alternator output by an integer divisor that varies in accordance with engine speed. Additional voltage regulation is provided by deleting selected cycles of the alternator output current as needed to maintain the RMS output voltage within predetermined limits.
    Type: Grant
    Filed: June 11, 1992
    Date of Patent: December 27, 1994
    Assignee: Generac Corporation
    Inventors: Robert Kern, Gerald Ruehlow, Graham McLean, Michael Wheeley, Frank Wedel, Mark Kastner
  • Patent number: 5280419
    Abstract: A method and a switching arrangement are provided for regulating a two-dimensional vector of a controlled system with a discrete value final controlling element having a limited switching frequency. The discrete value final controlling element also has limited number of actual-value vectors. A switching arrangement, such as a microprocessor, receives actual values for the two-dimensional vector as well as a reference vector and selects three actual-value vectors that are adjacent to the reference vector. The switching arrangement generates a reference trajectory which represents a sequence of vector settings for the discrete value final controlling element. A switch from one actual-value vector to another takes place when the distance between the two-dimensional vector and a next corner point of the reference trajectory is at a minimum. The resulting mean value of the generated two-dimensional vector is equal to the reference vector.
    Type: Grant
    Filed: March 26, 1992
    Date of Patent: January 18, 1994
    Assignee: Siemens Aktiengesellschaft
    Inventor: Gerald Amler
  • Patent number: 5270914
    Abstract: An apparatus and method is disclosed for an improved control system for a series resonant converter for transferring power between a source and a load. The control system comprises a series resonant circuit including a capacitor and an inductor with a first and second switching matrix connecting the series resonant circuit to the source and the load, respectively. A controller selects a combination of switches for transferring power between the source and the load using a single segment half-cycle resonant waveform that produces a final voltage on the capacitor within a preselected boundary.
    Type: Grant
    Filed: February 23, 1993
    Date of Patent: December 14, 1993
    Inventors: Hian K. Lauw, J. Ben Klaassens
  • Patent number: 5214366
    Abstract: A three-phase converter for polyphase induction motors has an input transformer with primary windings and at least two secondary windings associated with each primary winding, and controlled power semiconductors. Groups of power semiconductors are connected to the secondary windings such that the power semiconductors operate in series with the motor phases.
    Type: Grant
    Filed: June 18, 1992
    Date of Patent: May 25, 1993
    Assignee: Siemens Aktiengesellschaft
    Inventor: Rolf Hollmann
  • Patent number: 5198972
    Abstract: An improved commutation arrangement for an AC to AC or AC to DC energy converter circuit is disclosed. The improved arrangement uses turn-off capable commutation switches to enable modification of the operating waveforms in the cycloconverter. The modified waveforms include an operating concept wherein in lieu of always switching to the next lagging phase (as is done with conventional cycloconverters), an intervening switch is made to the leading phase when the output voltage is less than one-half of the maximum value. The disclosure includes mathematical consideration of source machine power factor, output waveform ripple content, interphase transformer characteristics, engine starting usage, and other refinements of the commutation arrangement.
    Type: Grant
    Filed: January 3, 1992
    Date of Patent: March 30, 1993
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventor: David L. Lafuze
  • Patent number: 5189603
    Abstract: A DC-to-AC electric power converting apparatus including an invertor circuit having a plurality of switching elements, a transformer connected to the invertor circuit, and a cyclo-converter circuit for converting the frequency of the output from the transformer. A carrier signal generator is provided for generating a carrier signal of a predetermined frequency.
    Type: Grant
    Filed: September 9, 1991
    Date of Patent: February 23, 1993
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Nobuo Sashida, Kazunori Sanada, Masato Koyama
  • Patent number: 5151853
    Abstract: A method of controlling a cycloconverter, for supplying an AC power having a given frequency to a converter group having at least two cascade-connected converters and controlling a firing angle of each of the converters, thereby converting the AC power supplied to the converter group into an AC power having a predetermined frequency, includes the steps of controlling an output voltage from a converter in one stage of the converter group to obtain an AC output voltage including a synthetic voltage of an AC voltage having an amplitude equal to a difference between a maximum output voltage of the converter and a DC voltage and a predetermined DC voltage in accordance with the polarity of a reference voltage signal having a predetermined frequency, controlling an output voltage from a converter in the other stage of the converter to obtain an AC output voltage obtained by subtracting the output from of the converter in one stage from the reference voltage signal, and continuously varying a voltage value of the DC
    Type: Grant
    Filed: March 13, 1991
    Date of Patent: September 29, 1992
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shinji Tatara, Masami Okayasu
  • Patent number: 5041960
    Abstract: An electrical circuit receives an alternating input signal and full-wave rectifies the alternating input signal. The rectified signal is then developed by the circuit into an output signal which has a frequency double the frequency of the alternating input signal. The doubled-frequency output signal is then output to a load. Alternatively, the circuit receives a direct current input signal, converts the direct current input signal into a periodically varying output signal, and outputs the periodically varying output signal to a load.
    Type: Grant
    Filed: February 20, 1990
    Date of Patent: August 20, 1991
    Inventor: Yefim Tseruel
  • Patent number: 5010471
    Abstract: An apparatus and method is disclosed for an improved AC--AC series-resonant converters incorporating power pulse modulation with internal frequencies of tens of kHz is applied to a series-resonant converter system for generating synthesized multiphase bipolar waveforms with reversible power flow and low distortion. The high pulse frequency allows the application of the principle of modulation and demodulation for fast system response. Switches are required which have bidirectional current conduction and voltage blocking ability. The conventional series-resonant AC--AC converter applies a total of 24 anti-parallel thyristors. The circuit configuration of the present invention is a series-resonant AC--AC converter with only 12 thyristors. Use of the converter results in a higher efficiency and lower costs.
    Type: Grant
    Filed: June 26, 1989
    Date of Patent: April 23, 1991
    Assignee: Robert F. Frijouf
    Inventors: J. Ben Klaassens, Hian K. Lauw, Freddy de Beer
  • Patent number: 5005115
    Abstract: An AC-to-AC converter operating as a current-source between an AC input line and an AC output line connected to a load, for instance an AC motor, includes three groups of bilateral switches controlled selectively within each group so as to generate a quasi square-wave current in each output phase while establishing a DC voltage between two of the output phases at a time, the third phase being idle, the magnitude of the output voltage being controlled in relation to the firing angle of the switches and the frequency being established by controlling the duration of each square-wave alternance. The duration of such alternances is set to 120 degrees of the output wave, followed and preceded by a 60 degree zero-current period.
    Type: Grant
    Filed: July 28, 1989
    Date of Patent: April 2, 1991
    Assignee: Westinghouse Electric Corp.
    Inventor: Colin D. Schauder
  • Patent number: 5003277
    Abstract: A phase-shifting transformer including main and series transformer units comprises a six-phase core including six independent magnetic circuits, numbered first through sixth from right to left. The combined U-, V-, and W-phase windings of the main transformer unit link with the fifth, third, and first magnetic circuits, respectively. The combined a-, b-, and c-phase windings of the series transformer unit link with the sixth, fourth, and second magnetic circuits. The winding directions of the V- and b-phase windings are reversed with respect to those of other phase windings. Thus, if three-phase voltages 120 degrees apart are input to the main transformer unit, then the phase angles between the main magnetic fluxes generated in any two adjacent magnetic circuits are equal to 30 degrees.
    Type: Grant
    Filed: August 8, 1989
    Date of Patent: March 26, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Katsuji Sokai, Koichi Ishii
  • Patent number: 4878163
    Abstract: In a power conversion system, a DC voltage of a DC power supply is converted into a predetermined high-frequency voltage by an inverter, and a high-frequency low voltage generated from the inverter is converted into a high-frequency high voltage by a transformer. A high-frequency high voltage generated from a secondary winding of the transformer is converted into a predetermined low-frequency voltage by a frequency changing circuit. The commutating operation of the frequency changing circuit is performed by a control circuit in response to the output current of the frequency changing circuit and in synchronism with the starting time of the short-circuiting prevention period of the inverter. As a result, the converted output of the power conversion system is prevented from decreasing.
    Type: Grant
    Filed: June 3, 1988
    Date of Patent: October 31, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Ikuo Yamato, Norikazu Tokunaga, Yasuo Matsuda, Hisao Amano
  • Patent number: 4875149
    Abstract: Polyphase inverters for converting AC power into polyphase AC output power typically experience phase shifts due to unbalanced phase loading. The resulting phase error is undesirable and should be eliminated, if possible. In order to overcome the foregoing problem, a control for maintaining N-1 phase outputs at desired angular displacements relative to a reference phase output determines the angular deviation of each of the N-1 phase outputs from the desired angular displacement for such phase output and adjusts a control waveform in time for each of a number of switches based upon the angular deviation of the phase output produced by such switch so that the angular deviations are minimized.
    Type: Grant
    Filed: December 16, 1988
    Date of Patent: October 17, 1989
    Assignee: Sundstrand Corporation
    Inventors: Christopher J. Rozman, Derrick I. Roe, Bradley J. Recker
  • Patent number: 4855887
    Abstract: A power conversion apparatus comprises an inverter for converting a voltage of a DC power source into AC power having a frequency higher than the commercial frequency, a transformer, fed by the inverter, for outputting AC power, which is adjusted at a desired voltage, a frequency converter, formed by two pairs of two gate turn-off thyristors (GTOs) connected in reverse-parallel, for converting the frequency of the AC power supplied from the transformer into the commercial frequency, and an energy regenerating device having capacitors for absorbing the energy of a spike voltage occurring due to a circuit inductance upon interruption of a current of each GTO of the frequency converter and a bridge circuit, formed by GTOs and diodes connected in reverse-paralel therewith, for switching over the direction of connecting the capacitors with a secondary winding of the transformer in accordance with the polarity of a voltage of the secondary winding in such a manner that the energy stored in the capacitors is regener
    Type: Grant
    Filed: September 22, 1988
    Date of Patent: August 8, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Ikuo Yamato, Norikazu Tokunaga, Yasuo Matsuda, Hisao Amano
  • Patent number: 4853664
    Abstract: A three-phase transformer for a cycloconverter comprising three primary windings to which three-phase currents of U-, V- and W-phase are individually applied as inputs, and six secondary windings which are provided for each of the primary windings and so arranged that D.C. components contained in six sets of three-phase signals delivered from the secondary windings are canceled in the respective phases, thereby to prevent D.C. components from being contained in currents which are supplied to the primary winding wound around the main legs of an iron core for the respective phases.
    Type: Grant
    Filed: October 26, 1987
    Date of Patent: August 1, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Masakatsu Asakura
  • Patent number: 4833588
    Abstract: In a direct AC to AC converter system the normal rectifier assistance functions are phase modulated by a lag and by a lead, and switching between lagging and leading function is effected at a high frequency according to a duty cycle: ##EQU1## and where .theta. is the electrical angle of the AC power supply, thereby insuring a sinusoidal input current in the system.
    Type: Grant
    Filed: August 31, 1988
    Date of Patent: May 23, 1989
    Assignee: Westinghouse Electric Corp.
    Inventor: Colin D. Schauder
  • Patent number: 4814967
    Abstract: A digitally-controlled cycloconverter converts a multiple-phase power signal of variable frequency into a single-phase or multiple-phase signal of a lower selected frequency. The cosinusoidal algorithm is utilized to determine the firing delay times, with the analog reference wave used in that algorithm being created from a digitized hardware table. The cosinusoidal algorithm is further simplified by defining the relationship between the analog reference wave and the cosinusoidal timing waves in terms of a two-part piecewise linear relationship which is incorporated into a digital algorithm. The digital algorithm is implemented on a system employing a high-power microprocessor having hardware multiplication and division capability, allowing the algorithm to be used with supply voltages having frequencies about those previously used for cycloconversion. The control logic involved with the firing of a series of thyristors is simplified by utilizing pulse transformers.
    Type: Grant
    Filed: March 21, 1988
    Date of Patent: March 21, 1989
    Inventors: M. Blythe Broughton, Michael J. Adams
  • Patent number: 4760321
    Abstract: An AC motor drive apparatus of this invention is constituted by an AC power source, a first circulating current type cycloconverter having an output terminal coupled to the AC power source, a phase-advanced capacitor coupled to an input terminal of the first cycloconverter, a second circulating current type cycloconverter having an input terminal coupled to the phase-advanced capacitor, and an AC motor coupled to an output terminal of the second cycloconverter. The first cycloconverter controls a current supplied from the AC power source to be a sine wave in the same phase as that of the power source voltage, so that a voltage crest value of the phase-advanced capacitor becomes substantially constant. The second cycloconverter supplies a sine wave current of a variable frequency to the AC motor.
    Type: Grant
    Filed: July 9, 1987
    Date of Patent: July 26, 1988
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shigeru Tanaka, Susumu Tadakuma
  • Patent number: 4751447
    Abstract: The present invention discloses a speed control apparatus for an AC motor which vector-controls, for example, a drive current of the AC motor such as an induction motor, synchronous motor and AC commutator motor with a feedback current control loop providing an inverter utilizing a semiconductor element for power amplification such as power transistor and compensates for non-linear current characteristic of the drive current generated by dead time resulting from ignition delay of a semiconductor element with a current compensation control element provided within the current control loop, thereby controlling the rotation speed and command response speed of an AC motor.
    Type: Grant
    Filed: October 30, 1986
    Date of Patent: June 14, 1988
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Hiroaki Okachi
  • Patent number: 4750098
    Abstract: Three terminal, six and twelve pulse unrestricted frequency changing circuits are provided by inserting controllable bidirectional switching circuits between open star configured coils in multiple phase windings of isolation transformers. Where the switched winding are secondaries of the isolation transformer, interphase transformers are provided between each pair of three pulse circuit groups and additional interphase transformers are required between six pulse circuit groups to provide a three terminal output. Where the switched windings are primary windings of the isolation transformer, the secondary windings are electrically connected in series with each other to provide the three terminal output.
    Type: Grant
    Filed: September 2, 1987
    Date of Patent: June 7, 1988
    Assignee: Westinghouse Electric Corp.
    Inventors: Theodore M. Heinrich, Andress Kernick, Peter Wood
  • Patent number: 4713744
    Abstract: A frequency converter is provided for a three-phase electric motor and has input connections for a multi-phase alternating current electric supply source, and output connections for connection to a three-phase electric motor. A SCR bridge including a plurality of SCRs interconnects the input connections and the output connections. A trigger circuit is connected to the SCR bridge for selective firing of the SCRs, in response to timing pulses generated upon zero crossing of the input means phases. Logic circuits interconnecting said timing pulse generators and the trigger circuits for effecting selective sequential firing of the SCRs at the zero crossings. Firing of said SCRs is respectively terminated by natural commutation. In one embodiment of the invention single phase current is converted to multiphase current.
    Type: Grant
    Filed: October 28, 1986
    Date of Patent: December 15, 1987
    Assignee: Torcon Products, Inc.
    Inventor: David B. Coston
  • Patent number: 4685049
    Abstract: The N converters of a UFC bridge system interconnecting an N-phase voltage source to N output loads, comprise each N bilateral switches connected to one end of the associated output load and (N-1) bilateral switches connected to the other end thereof. The (N-1) bilateral switches of the respective converters build up a polygonal assembly between the output loads which is selectively connected to the respective phases of the voltage source by selective control of the N groups of N switches and of the (N-1) groups of switches.
    Type: Grant
    Filed: July 22, 1986
    Date of Patent: August 4, 1987
    Assignee: Westinghouse Electric Corp.
    Inventor: Charles L. Neft
  • Patent number: 4680695
    Abstract: A current regulator for a variable frequency power supply includes a proportional plus integral circuit that produces a composite control output signal for each phase. To improve the performance of the current regulator at higher frequencies, the composite control output signal for each phase also inlcudes a cross coupled component which is produced by multiplying a d.c. signal proportional to frequency times an integrator output signal from another phase. The composite control signals are applied to a voltage source inverter which produces the output currents to a load.
    Type: Grant
    Filed: October 27, 1986
    Date of Patent: July 14, 1987
    Assignee: Allen-Bradley Company
    Inventors: Russel J. Kerkman, Timothy M. Rowan
  • Patent number: 4674026
    Abstract: A cycloconverter apparatus has three sets of AC/DC converters which are coupled to a 3-phase load and are connected in a delta fashion to form a circulating current type cycloconverter. Load currents to be supplied to the 3-phase load are controlled by a load current control circuit. Reactive power at the power supply side of the cycloconverter is detected by a reactive power detector. The sum of output currents from the converters is controlled by a current sum control circuit in accordance with a detected signal from the reactive power detector. The triggering phase of each of the converters is controlled by output signals from the load current control circuit and from the current sum control circuit. The controlled subject is the sum of the converter output currents, and the load currents are controlled directly.
    Type: Grant
    Filed: July 30, 1984
    Date of Patent: June 16, 1987
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Shigeru Tanaka
  • Patent number: 4673823
    Abstract: Power is fed to a plurality of loads by a respective plurality of circulating current type cycloconverters connected to an ac power supply. A power compensating capacitor common to the cycloconverters is provided at the ac power receiving-end to deliver a leading reactive power to the ac power supply. Further, each cycloconverter is provided with means for delivering a circulating current and means for delivering a circulating current command value to the circulating current control means. A lagging reactive power corresponding to the leading reactive power by the power factor compensating capacitor is delivered to the ac power supply. The power factor compensating capacitor may be configured so that its capacity is variable by changing the number of stages connected. In addition, the circulating current command value may vary depending upon the peak value of the current flowing in each cycloconverter.
    Type: Grant
    Filed: December 27, 1985
    Date of Patent: June 16, 1987
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Shigeru Tanaka
  • Patent number: 4661761
    Abstract: An internal combustion engine electrical system is disclosed which is adapted to use an internal combustion engine as a driving source. The generating system is constructed in a manner such that the output of an A.C. generator driven by the engine is rectified by a rectifier circuit, and the output of the rectifier circuit is inverted into an A.C. output by an inverter circuit adapted to use, a commutation command signal, the output of an oscillator circuit which generates a signal of a constant frequency.
    Type: Grant
    Filed: February 11, 1985
    Date of Patent: April 28, 1987
    Assignee: Kokusan Denki Co., Ltd.
    Inventor: Mitsuo Katsumata
  • Patent number: 4658346
    Abstract: Apparatus for converting relatively high, variable frequency, variable amplitude electrical power into substantially constant amplitude and substantially constant, relatively lower frequency power of a preselected waveform. The power source signal is divided into a number of varying amplitude, same frequency segments. The segment having the amplitude nearest that of the preselected waveform is transmitted by a switching network during each of many time periods. The switching network is preferably controlled by a microprocessor that senses the amplitudes of the segments and compares them to the desired waveform amplitude as a function of time. The microprocessor provides control signals to the switching network in response to the comparison. Because the low frequency output signal is constructed with reference to a memorized signal, the output signal is particularly stable in spite of variations in the power source signal.
    Type: Grant
    Filed: December 11, 1985
    Date of Patent: April 14, 1987
    Assignee: Kennecott Corporation
    Inventor: Frederick E. Templeton