Patents by Inventor Alfred Rufer
Alfred Rufer 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).
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Patent number: 8723365Abstract: A device for supplying power to a load, requiring both a pre-determined supply of electrical power and high power for short durations of the operating cycle of the load, where the operating cycle is repeated. The power supply device includes a connection to an electrical grid, an AC voltage transformation circuit, a voltage rectification means and a plurality of DC/DC converters mounted in series to terminals of the load. Each of the DC/DC converters has a storage capacitor mounted in parallel to it and at least one of the DC/DC converters is supplied directly by the voltage rectification means. At least another one of the DC/DC converters is not supplied directly by the voltage rectification means. The power supply device may compensate for losses in the power supply device and load, and may substantially continually and uniformly balance voltages at terminals of the storage capacitors.Type: GrantFiled: December 16, 2008Date of Patent: May 13, 2014Assignees: Ecole Polytechnique Federale de Lausanne (EPFL), European Organization for Nuclear ResearchInventors: Frederick Bordry, Jean-Paul Burnet, Claude Fahrni, Alfred Rufer
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Patent number: 8567183Abstract: Multistage hydraulic systems and methods for converting the potential energy of a pressurized gas, particularly air, into mechanical work when operating in motor, and for producing compressed gas from the mechanical work of the rotating shaft when rotating when operating in compressor mode, by performing a successive expansion/compression of the said gas. Each of the systems comprises: a multistage Compression-Expansion Unit made of several hydraulic Compression-Expansion Modules having different capacity and integrating a gas/liquid separating heat exchanger, designed to convert pressure power into a hydraulic power and vice-versa, by performing an essentially isothermal compression/expansion of the gas; a single stage or multistage, direct or indirect, external forced-air Heat Exchanger for maintaining the active liquid at ambient temperature; and a multi-circuit, multi-displacement Hydraulic Motor/Pump for converting hydraulic power into mechanical power and vice-versa.Type: GrantFiled: September 12, 2008Date of Patent: October 29, 2013Assignee: Ecole Polytechnique Federale de Lausanne (EPFL)Inventors: Sylvain Lemofouet, Alfred Rufer
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Patent number: 8378521Abstract: Different types of energy storage systems are described, in particular hydro-pneumatic storage systems. In one, energy is stored by compressing gas in a chamber (44,45,54,55) with a liquid piston and released by gas expansion. A spray head or grid at the top of the chamber (44,45,54,55) supplies liquid as a shower through the gas being compressed or expanding in the cylinder (11,12) to maintain an isothermal condition. In another, energy is stored from an array of solar cells connected to an array of supercapacitors forming an auxiliary storage, and a main energy storage device such as a hydro-pneumatic storage system, for supply to an AC or DC network. The efficiency is improved by connecting the solar cells via the array of supercapacitors to the AC or DC network.Type: GrantFiled: May 9, 2007Date of Patent: February 19, 2013Assignee: Ecole Polytechnique Federale de Lausanna (EPFL)Inventors: Alfred Rufer, Daniel Favrat, Philippe Barrade, Sylvain Lemofouet
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Publication number: 20100199652Abstract: Multistage hydraulic systems and methods for converting the potential energy of a pressurized gas, particularly air, into mechanical work when operating in motor, and for producing compressed gas from the mechanical work of the rotating shaft when rotating when operating in compressor mode, by performing a successive expansion/compression of the said gas. Each of the systems comprises: a multistage Compression-Expansion Unit made of several hydraulic Compression-Expansion Modules having different capacity and integrating a gas/liquid separating heat exchanger, designed to convert pressure power into a hydraulic power and vice-versa, by performing an essentially isothermal compression/expansion of the gas; a single stage or multistage, direct or indirect, external forced-air Heat Exchanger for maintaining the active liquid at ambient temperature; and a multi-circuit, multi-displacement Hydraulic Motor/Pump for converting hydraulic power into mechanical power and vice-versa.Type: ApplicationFiled: September 12, 2008Publication date: August 12, 2010Inventors: Sylvain Lemofouet, Alfred Rufer
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Publication number: 20100133903Abstract: Different types of energy storage systems are described, in particular hydro-pneumatic storage systems. In one, energy is stored by compressing gas in a chamber (44,45,54,55) with a liquid piston and released by gas expansion. A spray head or grid at the top of the chamber (44,45,54,55) supplies liquid as a shower through the gas being compressed or expanding in the cylinder (11,12) to maintain an isothermal condition. In another, energy is stored from an array of solar cells connected to an array of supercapacitors forming an auxiliary storage, and a main energy storage device such as a hydro-pneumatic storage system, for supply to an AC or DC network. The efficiency is improved by connecting the solar cells via the array of supercapacitors to the AC or DC network.Type: ApplicationFiled: May 9, 2007Publication date: June 3, 2010Inventors: Alfred Rufer, Daniel Favrat, Philippe Barrade, Sylvain Lemofouet
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Patent number: 7245031Abstract: A generator having electronic circuit breakers as circuit breakers, whereby circuits comprising thyristors, IGBT elements and/or GTO thyristors are used, and whereby the circuit breakers are integrated into the generator, preferably in that the circuit breakers are distributed on parallel winding branches of the stator. Such power electronics can also be used for switching generators having a power above 50 MV with very short switching times of a few milliseconds.Type: GrantFiled: March 29, 2005Date of Patent: July 17, 2007Assignee: Alstom Technology Ltd.Inventors: Oliver Drubel, Reinhard Joho, Jean-Jacques Simond, Alfred Rufer
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Patent number: 7180270Abstract: The present invention relates to a method and to a device for adapting the alternating current generated by a generator (1) and the alternating voltage generated by a generator (1) to a grid (8), whereby the generator (1) has at least one excitation coil (2). The power fed into the grid (8) can be flexibly adapted while entailing low switching losses in that a static frequency converter (9) is employed for the adaptation between the generator (1) and the grid (8), and in that, in order to control the power fed into the grid (8), means (3) are provided with which, on the one hand, the strength of the excitation field generated by the at least one excitation coil (2) is regulated and, on the other hand, the phase angle between the frequency converter voltage and the generator or grid voltage is appropriately controlled.Type: GrantFiled: January 4, 2006Date of Patent: February 20, 2007Assignee: Alstom Technology Ltd.Inventors: Alfred Rufer, Martin Veenstra
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Publication number: 20060214645Abstract: The present invention relates to a method and to a device for adapting the alternating current generated by a generator (1) and the alternating voltage generated by a generator (1) to a grid (8), whereby the generator (1) has at least one excitation coil (2). The power fed into the grid (8) can be flexibly adapted while entailing low switching losses in that a static frequency converter (9) is employed for the adaptation between the generator (1) and the grid (8), and in that, in order to control the power fed into the grid (8), means (3) are provided with which, on the one hand, the strength of the excitation field generated by the at least one excitation coil (2) is regulated and, on the other hand, the phase angle between the frequency converter voltage and the generator or grid voltage is appropriately controlled.Type: ApplicationFiled: January 4, 2006Publication date: September 28, 2006Applicant: ALSTOM Technology LtdInventors: Alfred Rufer, Martin Veenstra
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Publication number: 20060181818Abstract: A generator having electronic circuit breakers as circuit breakers, whereby circuits comprising thyristors, IGBT elements and/or GTO thyristors are used, and whereby the circuit breakers are integrated into the generator, preferably in that the circuit breakers are distributed on parallel winding branches of the stator. Such power electronics can also be used for switching generators having a power above 50 MV with very short switching times of a few milliseconds.Type: ApplicationFiled: March 29, 2005Publication date: August 17, 2006Applicant: ALSTOM Technology LtdInventors: Oliver Drubel, Reinhard Joho, Jean-Jacques Simond, Alfred Rufer
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Patent number: 4904920Abstract: To reduce harmonics in an induction machine (33) which is fed by a self-commutated inverter (30), the trajectory of the flux vector of the induction machine is conducted along an edge path having at least 2.sup.p .multidot.q.multidot.m edges, where p is an integral number .gtoreq.1, q.gtoreq.2 is the number of voltage stages of the inverter and m.gtoreq.2 is the number of phases of the induction machine. In this arrangement, the flux vector is alternatingly conducted along straight and zig-zag segments. This reduction is essentially achieved by means of at least one second flux conducting circuit having a second coordinate con=verter (56) and a second comparator (57) in addition to a first flux conducting circuit having a first coordinate converter (54) and first comparator (46), the flux components (.psi..sub..beta.1' -.psi..sub..beta.3') at the output of the second coordinate converter being shifted by 30.degree. in phase with respect to the flux components (.psi..sub..beta.1 -.psi..sub..beta.Type: GrantFiled: June 24, 1988Date of Patent: February 27, 1990Assignee: BBC Brown Boveri AGInventor: Alfred Rufer