Patents Assigned to Nidec SR Drives Ltd.
  • Patent number: 9887657
    Abstract: A controller for a switched reluctance machine is operated to close a switch which would otherwise be open so as to connect a phase winding to the DC link to which the winding is connected during other parts of the electrical cycle. This produces a condition which allows the insulation of the system to be monitored by applying a voltage between the DC link and ground.
    Type: Grant
    Filed: October 12, 2016
    Date of Patent: February 6, 2018
    Assignee: NIDEC SR DRIVES, LTD
    Inventors: Michael Paul Tankard, Paul Andrew Sykes, Ian Jordison
  • Patent number: 9575104
    Abstract: In an electrical machine which has unidirectional excitation applied to its windings, the mean values of voltage and current can be computed from the instantaneous phase voltage and current by the use of, for example, low-pass filters (in either the analogue or digital domain). The value of winding resistance can then be calculated by dividing the mean voltage by the mean current. This avoids the cost, fragility and potential inaccuracy of conventional temperature sensors, and provides the controller with an ongoing estimate of winding temperature.
    Type: Grant
    Filed: December 3, 2013
    Date of Patent: February 21, 2017
    Assignee: NIDEC SR DRIVES LTD.
    Inventor: Michael James Turner
  • Patent number: 9312801
    Abstract: A brushless electrical machine has at least one phase winding which produces torque to drive a load. The control system for the machine is able to vary the flux and current supplied to a phase so as to vary the torque output as a function of the rotor position. The energization is reduced at particular angles to produce a dip in the torque profile, thus ensuring that, if the drive stalls, it does so at a predetermined position, for example where the losses in the drive are minimized.
    Type: Grant
    Filed: February 25, 2014
    Date of Patent: April 12, 2016
    Assignee: NIDEC SR DRIVES, LTD
    Inventors: Steven Paul Randall, Mark John Cherney
  • Patent number: 9246363
    Abstract: A rotating electrical machine has a rotor composed of laminations having salient poles. The poles have one or more holes which are positioned so as to reduce the peak stress experienced by the laminations when the rotor is rotating. The holes are chosen according to a disclosed design procedure which gives a reduction in peak stress for a given limit on the output of the machine.
    Type: Grant
    Filed: May 11, 2011
    Date of Patent: January 26, 2016
    Assignee: NIDEC SR DRIVES, LTD
    Inventors: Phillip George Dickinson, Paul Andrew Sykes, Norman Neilson Fulton, Thilak Raj Durairaj
  • Patent number: 9024556
    Abstract: In an electrical machine which has time-varying or position-varying disturbances in its output, signals representing the position and values of machine-related parameters are used to solve a model of the machine to calculate the phase currents which are required to minimize the disturbances. The model is able to provide solutions in the presence of limitations of some of the operating conditions of the machine, for example the supply voltage or the error in the signal representing the position.
    Type: Grant
    Filed: June 27, 2012
    Date of Patent: May 5, 2015
    Assignee: Nidec SR Drives, Ltd.
    Inventors: Michael Ian Peter Henderson, Joseph Gerald Marcinkiewicz
  • Publication number: 20140239862
    Abstract: A brushless electrical machine has at least one phase winding which produces torque to drive a load. The control system for the machine is able to vary the flux and current supplied to a phase so as to vary the torque output as a function of the rotor position. The energisation is reduced at particular angles to produce a dip in the torque profile, thus ensuring that, if the drive stalls, it does so at a predetermined position, for example where the losses in the drive are minimised.
    Type: Application
    Filed: February 25, 2014
    Publication date: August 28, 2014
    Applicant: NIDEC SR DRIVES LTD.
    Inventors: Steven Paul Randall, Mark John Cherney
  • Publication number: 20140159754
    Abstract: In an electrical machine which has unidirectional excitation applied to its windings, the mean values of voltage and current can be computed from the instantaneous phase voltage and current by the use of, for example, low-pass filters (in either the analogue or digital domain). The value of winding resistance can then be calculated by dividing the mean voltage by the mean current. This avoids the cost, fragility and potential inaccuracy of conventional temperature sensors, and provides the controller with an ongoing estimate of winding temperature.
    Type: Application
    Filed: December 3, 2013
    Publication date: June 12, 2014
    Applicant: Nidec SR Drives Ltd.
    Inventor: Michael James Turner
  • Publication number: 20130009579
    Abstract: In an electrical machine which has time-varying or position-varying disturbances in its output, signals representing the position and values of machine-related parameters are used to solve a model of the machine to calculate the phase currents which are required to minimise the disturbances. The model is able to provide solutions in the presence of limitations of some of the operating conditions of the machine, for example the supply voltage or the error in the signal representing the position.
    Type: Application
    Filed: June 27, 2012
    Publication date: January 10, 2013
    Applicant: NIDEC SR DRIVES, LTD.
    Inventors: Michael Ian Peter Henderson, Joseph Gerald Marcinkiewicz
  • Patent number: 8169109
    Abstract: A switched reluctance machine has an array of poles attached to a stationary holding member to form a stator. The stator has no back-iron. The machine has two arrays of rotor poles, positioned on either side of the stator poles, and circumferentially aligned with each other. When a pair of rotor poles is aligned with a stator pole, a small airgap is formed at each end of the stator pole, across which flux can be driven to produce torque in a rotary arrangement or force in a linear arrangement. When the poles are in the unaligned position, the phase inductance is very low.
    Type: Grant
    Filed: March 11, 2010
    Date of Patent: May 1, 2012
    Assignee: Nidec SR Drives Ltd.
    Inventors: Paul Andrew Sykes, Phillip George Dickinson
  • Patent number: 8125113
    Abstract: A wound core assembly for an electrical machine comprising a stack of laminations defining a core having a plurality of poles, the wound core assembly further comprising at least one slot wedge, wherein the slot wedge comprises a first portion arranged between adjacent poles and at least one second portion protruding from the first portion and abutting an end face of the core in the region of at least one of the poles. The at least one second portion may apply axial pressure to the end face to reduce the tendency of the laminations to splay axially outwards.
    Type: Grant
    Filed: September 30, 2009
    Date of Patent: February 28, 2012
    Assignee: Nidec SR Drives Ltd.
    Inventors: Michael James Turner, Simon David Gibson
  • Patent number: 8121819
    Abstract: An electrical drive system includes an electrical machine controlled by an electronic controller and requires control signals representing quantities associated with the operation of the electrical machine. These signals may represent, for example, rotor position and flux or current. A controller includes an estimation routine to use the known magnetic characteristics of the machine and a rotor position signal to provide an estimate of current or of supply voltage.
    Type: Grant
    Filed: November 13, 2008
    Date of Patent: February 21, 2012
    Assignee: Nidec SR Drives Ltd.
    Inventors: Michael Paul Tankard, James Douglas Alexander Chambers
  • Publication number: 20110285242
    Abstract: A rotating electrical machine has a rotor composed of laminations having salient poles. The poles have one or more holes which are positioned so as to reduce the peak stress experienced by the lamination when the rotor is rotating. The holes are chosen according to a disclosed design procedure which gives a reduction in peak stress for a given limit on the output of the machine.
    Type: Application
    Filed: May 11, 2011
    Publication date: November 24, 2011
    Applicant: NIDEC SR DRIVES LTD.
    Inventors: Phillip George Dickinson, Paul Andrew Sykes, Norman Neilson Fulton, Thilak Raj Durairaj
  • Patent number: 8049528
    Abstract: An electrical drive system includes an electrical machine controlled by an electronic controller, which requires feedback of signals representing quantities associated with the operation of the electrical machine. These signals may represent, for example, flux, current and/or rotor position. The integrity of these signals is validated by setting suitable thresholds for the signals and confirming that both are present at the appropriate time.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: November 1, 2011
    Assignee: Nidec SR Drives Ltd.
    Inventor: Peter Richard Mayes