Patents by Inventor Klaus F. Hoffmann

Klaus F. Hoffmann 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: 10298131
    Abstract: An apparatus for controlling a switching DC-DC converter with a first half-bridge circuit including a first switch and a second switch, with a second half-bridge circuit including a third switch and a fourth switch and with an inductance connected between the center taps of the first and the second half-bridge circuit includes, according to embodiments, a control unit that is configured to adapt, in dependence on an input voltage and an output voltage at the switching DC-DC converter, a switching frequency of the switches of the DC-DC converter, the duty cycles of the first and fourth switch and the time delay between switching on the first and the fourth switch. The control unit is configured to determine the switching frequency, the first duty cycle, the second duty cycle and the time delay based on an output current of the switching DC-DC converter.
    Type: Grant
    Filed: April 13, 2018
    Date of Patent: May 21, 2019
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Zhe Yu, Holger Kapels, Klaus F. Hoffmann
  • Publication number: 20180287498
    Abstract: An apparatus for controlling a switching DC-DC converter with a first half-bridge circuit including a first switch and a second switch, with a second half-bridge circuit including a third switch and a fourth switch and with an inductance connected between the center taps of the first and the second half-bridge circuit includes, according to embodiments, a control unit that is configured to adapt, in dependence on an input voltage and an output voltage at the switching DC-DC converter, a switching frequency of the switches of the DC-DC converter, the duty cycles of the first and fourth switch and the time delay between switching on the first and the fourth switch. The control unit is configured to determine the switching frequency, the first duty cycle, the second duty cycle and the time delay based on an output current of the switching DC-DC converter.
    Type: Application
    Filed: April 13, 2018
    Publication date: October 4, 2018
    Inventors: Zhe YU, Holger KAPELS, Klaus F. HOFFMANN
  • Patent number: 9923466
    Abstract: Embodiments of the present invention provide a DC-DC converter having a first DC voltage gate, a second DC voltage gate and a storage choke. The storage choke is coupled between the first DC voltage gate and the second DC voltage gate by means of electric switching elements. The DC-DC converter is configured such that a direction of a current flow through the storage choke is inverted at least once during a switching period of the electric switching elements. Further, the DC-DC converter is configured to track or readjust a switching frequency of the electric switching elements in case of a change of operating parameters of the DC-DC converter such that a change of direction of the current flow through the storage choke during a switching period of the electric switching elements is ensured.
    Type: Grant
    Filed: March 10, 2016
    Date of Patent: March 20, 2018
    Assignee: Fraunhofer-Gesellschaft Zur Foerderung Der Angewandlen Forschung E.V.
    Inventors: Zhe Yu, Klaus F. Hoffmann, Holger Kapels
  • Publication number: 20160190932
    Abstract: Embodiments of the present invention provide a DC-DC converter having a first DC voltage gate, a second DC voltage gate and a storage choke. The storage choke is coupled between the first DC voltage gate and the second DC voltage gate by means of electric switching elements. The DC-DC converter is configured such that a direction of a current flow through the storage choke is inverted at least once during a switching period of the electric switching elements. Further, the DC-DC converter is configured to track or readjust a switching frequency of the electric switching elements in case of a change of operating parameters of the DC-DC converter such that a change of direction of the current flow through the storage choke during a switching period of the electric switching elements is ensured.
    Type: Application
    Filed: March 10, 2016
    Publication date: June 30, 2016
    Inventors: Zhe Yu, Klaus F. Hoffmann, Holger Kapels
  • Publication number: 20140241507
    Abstract: An electrical energy supply system (12) comprises an input rectifier (14) for rectifying an input voltage into a DC voltage, an inverter (18) with semiconductor switches for generating an AC output voltage from the DC voltage and a controller (24) for switching the switches of the inverter (18). The inverter (18) is adapted for generating a 5-level AC output voltage. The controller (18) is adapted to switch the semiconductor switches such that an asymmetric pulse shape is generated from the inverter (18) in a half cycle of the AC output voltage.
    Type: Application
    Filed: October 15, 2012
    Publication date: August 28, 2014
    Applicant: KONINKLIJKE PHILIPS N.V.
    Inventors: Oliver Woywode, Christian Düerkop, Klaus F. Hoffmann