Patents Assigned to Ballard Power Systems
  • Fuel cell resuscitation method and apparatus
    Patent number: 6861167
    Abstract: A fuel cell system includes fuel cells forming a fuel cell stack, having a fuel passage and an oxidant passage. A purge valve is coupled to the fuel passage to exhaust contaminants, and a controller is coupled to temporarily increase the oxidant stream flow rate through the oxidant passage, and to temporarily open the fuel purge valve, if a voltage across a pair of fuel cells is less than a defined threshold voltage. In this resuscitation step, the oxidant flow rate can be temporarily increased by increasing a duty cycle of an air compressor by approximately 50% for a duration of between approximately 5 to 10 seconds. The controller can further shut down fuel cell operation if a voltage across a pair of fuel cells is less than a defined threshold voltage in an inter-resuscitation period immediately following the resuscitation step.
    Type: Grant
    Filed: July 25, 2001
    Date of Patent: March 1, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Brian Wells, Tan Duc Uong, Charles Joseph Schembri, Gregory A. James, George Alexander Skinner, Benno Giesecke
  • Method and system for non-invasive power transistor die voltage measurement
    Patent number: 6861835
    Abstract: A non-invasive, non-destructive method and system for determining power transistor peak die voltage utilizes values for each of a plurality of parameters determined by measurement of external terminal voltages for any number of switches, such as transistors of an inverter. Stray inductance values are calculated and used with measured current gradient to calculate the peak die voltages for the switches. A refinement of the method determines transistor peak die voltage without measuring current.
    Type: Grant
    Filed: December 3, 2002
    Date of Patent: March 1, 2005
    Assignee: Ballard Power Systems Corporation
    Inventors: Douglas K. Maly, Orrin B. West, Chingchi Chen
  • Ride through in electronic power converters
    Publication number: 20050030045
    Abstract: A system comprising a current sensor to sense a current provided by an electronic power converter, the current sensor comprising an output; an overcurrent detection circuit comprising an input coupled to an output of the current sensor; and a logic control circuit configurable to maintain the current provided by the electronic power converter in response to the sensed current having a short circuit magnitude, the logic control circuit comprising an input coupled to an output of the overcurrent detection circuit and at least one output coupled to at least one switch of the electronic power converter.
    Type: Application
    Filed: August 6, 2003
    Publication date: February 10, 2005
    Applicant: Ballard Power Systems Corporation
    Inventors: Duo Deng, Kerry Grand, Steven Kowalec
  • Anti-islanding device and method for grid connected inverters using random noise injection
    Patent number: 6853940
    Abstract: A device and method for detecting islanding of a grid connected inverter makes use of an injected white noise as a perturbing force on the output voltage of the inverter. The white noise is injected at least once in every cycle and can be generated at different rates in implementation. On loss of the grid, a frequency drift of the output voltage is detected and a positive feedback is activated that accelerates the drift.
    Type: Grant
    Filed: January 15, 2003
    Date of Patent: February 8, 2005
    Assignee: Ballard Power Systems Corporation
    Inventor: Anil Tuladhar
  • Fuel cell assembly with an improved gas sensor
    Patent number: 6852434
    Abstract: A fuel cell assembly has an improved gas sensor. The improved sensor measures the gas concentrations in the interior fluid passages within a fuel cell assembly or within fluid passages employed to transport reactant fluid streams to or from the fuel cell(s). The improved sensor is particularly suited for use in the environment within the reactant fluid passages of a solid polymer fuel cell assembly and is tolerant to the presence of water. The sensor employs an active electrode; a passive electrode; and an electrolyte in contact with both electrodes. The electrolyte is disposed on a substrate and a heater is located in thermal contact with the substrate for heating the substrate and the electrolyte.
    Type: Grant
    Filed: December 15, 2000
    Date of Patent: February 8, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Michael Reindl, Thomas Roesch, Ralf Erich Moos, Thomas Alfred Birkhofer, Wilhelm Mueller, Ralf Wolfgang Mueller
  • Method and apparatus for adjusting wakeup time in electrical power converter systems and transformer isolation
    Publication number: 20050018454
    Abstract: An electrical power converter system adjusts a wakeup voltage periodically, to permit earlier connection and/or operation, to increase performance. The electrical power converter system selects between a mathematically adjusted wakeup voltage based on at least one previous period, and a table derived wakeup voltage that takes into account historical information. The electrical power converter system is particularly suited to applications with periodicity such as solar based photovoltaic power generation.
    Type: Application
    Filed: May 12, 2004
    Publication date: January 27, 2005
    Applicant: Ballard Power Systems Corporation
    Inventors: Duo Deng, Anil Tuladhar, Kent Harmon
  • Apparatus and method to achieve multiple effective ratios from a fixed ratio transaxle
    Patent number: 6843749
    Abstract: A motor vehicle drive train assembly for achieving multiple effective ratios from a single ratio transaxle enables application of a fixed ratio transaxle, such as used in electric vehicle drive trains, to a multi-speed requirement, for example, in airport ground support equipment. Multiple configurations are enabled by varying the relative speed of the outputs through the differential of the transaxle, such as bringing one of the outputs to zero, or by using another motor to control the speed of one of the outputs.
    Type: Grant
    Filed: January 16, 2003
    Date of Patent: January 18, 2005
    Assignee: Ballard Power Systems Corporation
    Inventors: William Kelledes, Richard L. Willis
  • Substrate-level DC bus design to reduce module inductance
    Patent number: 6845017
    Abstract: A DC bus for use in a power module includes a positive DC conductor bus plate parallel with a negative DC conductor bus plate. The positive bus and negative bus permit counter-flow of currents, thereby canceling magnetic fields and their associated inductances, and the positive and negative bus are connectable to the center portion of a power module.
    Type: Grant
    Filed: September 20, 2001
    Date of Patent: January 18, 2005
    Assignee: Ballard Power Systems Corporation
    Inventors: Sayeed Ahmed, Scott Parkhill, Fred Flett, Douglas Maly
  • Overmodulation systems and methods for induction motor control
    Patent number: 6844701
    Abstract: Systems and methods for controlling an induction motor including detecting a field weakening operation state of the motor, wherein the field weakening operation state is detected when a flux current, Id, in the motor is reduced to a predetermined fraction of its normal, non-voltage limited value. The systems and methods also including an overmodulation operation state of the motor before said field weakening operation state is detected and enabling the overmodulation operation state of the motor after said field weakening operation state is detected.
    Type: Grant
    Filed: January 15, 2003
    Date of Patent: January 18, 2005
    Assignee: Ballard Power Systems Corporation
    Inventors: Li Chen, Richard J. Hampo, Venkatapathi R. Nallapa
  • Separator with fluid distribution features for use with a membrane electrode assembly in a fuel cell
    Patent number: 6844101
    Abstract: Electrochemically inactive separators may be employed at the periphery of membrane electrode assemblies in fuel cells (such as solid polymer electrolyte fuel cells) to separate the various fluids within (for example, reactants, coolant). Complex fluid distribution features may be incorporated into these separators, thereby desirably simplifying the design and manufacture of other fuel cell components, such as the flow field plates employed to distribute fluids to the cell electrodes. This is particularly advantageous in fuel cells comprising thin, corrugated flow field plates. The separators may be bonded to the membrane electrode assemblies to form convenient, unitary structures.
    Type: Grant
    Filed: January 4, 2002
    Date of Patent: January 18, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: Alvin Lee, Joerg Zimmermann, Olen Vanderleeden
  • Power converter system
    Patent number: 6845020
    Abstract: A power conversion system which comprises a controller and conversion assemblies which selectively rectify and invert an electrical signal. Conversion assemblies comprise a plurality of integrated gate bipolar transistor assemblies. The power conversion system is effective to convert DC current to AC current, to convert AC current to DC current, and to control the output frequency of a received electrical signal to a conventional operating range.
    Type: Grant
    Filed: June 2, 2003
    Date of Patent: January 18, 2005
    Assignee: Ballard Power Systems Corporation
    Inventors: Duo Deng, Dumitru D. Raceu, Kent M. Harmon
  • Impregnation of ion-exchange membranes to improve electrochemical fuel cell performance
    Patent number: 6841285
    Abstract: The electrochemical performance of an ion-exchange membrane in a fuel cell system may be improved by impregnating therein a perfluoroamine. The amine may be primary, secondary or tertiary. Further, the amine is preferably water insoluble or only slightly water soluble. For example, the amine may be perfluorotriamylamine or perfluorotributylamine. Use of such a membrane system within a fuel cell may allow high or low temperature operation (i.e. at temperatures greater than 100° C. or less than 0° C.) as well as operation at low relative humidity.
    Type: Grant
    Filed: August 28, 2002
    Date of Patent: January 11, 2005
    Assignee: Ballard Power Systems Inc.
    Inventors: David P. Wilkinson, Joy A. Roberts, Nengyou Jia, Eagranie Yuh, Shanna D. Knights, Jean St-Pierre
  • Method and apparatus for controlling voltage from a fuel cell system
    Patent number: 6841275
    Abstract: A fuel cell system electrically couples a battery in parallel with the fuel cell stack to power a load. An operational condition of the battery is compared to a desired operating condition and a partial pressure of a reactant flow to at least a portion of the fuel cell stack is adjusted based on the determined amount of deviation. The operational condition can include voltage, charge of the battery. Individual fuel cell systems can be combined in series and/or parallel to produce a combined fuel cell system having a desired output voltage and current.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: January 11, 2005
    Assignee: Ballard Power Systems Inc.
    Inventor: Martin T. Pearson
  • Method and apparatus for tracking maximum power point for inverters, for example, in photovoltaic applications
    Publication number: 20050002214
    Abstract: A power system employs an outer voltage feedback loop and an inner current feedback loop to control a power converter, such as a DC to AC inverter for transferring electrical power between a power source, for example a photovoltaic array, and a load, for example a power grid. The outer loop accommodates variations in the output of the power source, for example accommodating anomalies in IV characteristics such as IV droop characteristic associated with photovoltaic cells. The outer loop may employ a first control regime or a second control regime, for example, dependent on whether a DC bus voltage or power is smaller than a value corresponding to measurement resolution or expected noise.
    Type: Application
    Filed: April 30, 2004
    Publication date: January 6, 2005
    Applicant: Ballard Power Systems Corporation
    Inventors: Duo Deng, Anil Tuladhar, Kenneth Farkas, Kerry Grand
  • Power supply and ultracapacitor based battery simulator
    Patent number: 6838923
    Abstract: An ultracapacitor based power storage device suitable for use in hybrid fuel cell systems and other power systems includes circuitry for simulating the response of a battery. A voltage current limiting circuit may be employed with a variety of electrical storage devices, for example, ultracapacitors and batteries.
    Type: Grant
    Filed: May 16, 2003
    Date of Patent: January 4, 2005
    Assignee: Ballard Power Systems Inc.
    Inventor: Martin T. Pearson
  • Method and apparatus for determining a maximum power point of photovoltaic cells
    Publication number: 20040264225
    Abstract: The maximum power point (MPP) of a photovoltaic array that can be coupled to power inverter is determined. A capacitor on a DC-bus side of the inverter is used as a load from which I-V characteristics of the photovoltaic array can be generated. The photovoltaic array is connected to the capacitor, which has been previously discharged by a bleed down resistor. Short circuit current, open circuit voltage, and values of current and voltage as the capacitor charges are determined and used to generate I-V characteristics of the photovoltaic array. From the I-V characteristics, the MPP can be calculated.
    Type: Application
    Filed: April 30, 2004
    Publication date: December 30, 2004
    Applicant: Ballard Power Systems Corporation
    Inventors: Vijay Bhavaraju, Kerry E. Grand, Anil Tuladhar
  • Method of making a membrane electrode assembly for electrochemical fuel cells
    Publication number: 20040258979
    Abstract: A membrane electrode assembly may be made using a one-sided catalyst coated membrane (CCM) wherein only one catalyst layer, either the anode or the cathode, is coated directly on the ion-exchange membrane. In particular, a one-sided CCM may be used where it may not be practicable to coat both sides of the ion-exchange membrane with catalyst layers such as when PTFE is added to the anode catalyst layer to render it reversal tolerant.
    Type: Application
    Filed: June 20, 2003
    Publication date: December 23, 2004
    Applicant: Ballard Power Systems Inc.
    Inventors: Siyu Ye, Paul Beattie, Todd E. Wilke, Shannon R. Hodgson, Kyoung Bai, Michael V. Lauritzen
  • Multilevel inverter control schemes
    Publication number: 20040252531
    Abstract: A multilevel inverter control system having logic configured to substantially minimize an area difference between a target waveform and a step signal of a multilevel inverter.
    Type: Application
    Filed: June 13, 2003
    Publication date: December 16, 2004
    Applicant: Ballard Power Systems Corporation
    Inventors: Bing Cheng, Fengtai Huang
  • Electrochemical fuel cell with fluid distribution layer having non-uniform permeability
    Publication number: 20040253504
    Abstract: An electrochemical fuel cell comprises an anode electrocatalyst layer, a cathode electrocatalyst layer, a polymer electrolyte membrane interposed between the anode and cathode electrocatalyst layers, an anode flow field plate, a cathode flow field plate, an anode fluid distribution layer interposed between the anode flow field plate and the anode electrocatalyst layer, and a cathode fluid distribution layer interposed between the cathode flow field plate and the cathode electrocatalyst layer, wherein at least one of the anode and cathode fluid distribution layers decreases in permeability from an inlet to an outlet of the electrochemical fuel cell. Methods for making a substantially fluid impermeable sheet material having a non-uniform pattern of perforations are also provided.
    Type: Application
    Filed: June 10, 2003
    Publication date: December 16, 2004
    Applicant: Ballard Power Systems Inc.
    Inventors: Alexander Mossman, Emerson R. Gallagher
  • Method for controlling the quality of the coolant for fuel cell systems
    Patent number: 6830843
    Abstract: A method for controlling the quality of the coolant for fuel cell systems, it being proposed to measure and monitor the insulation resistance of the load circuit of the fuel cell system. It has become apparent that there is a functional, uniquely defined relationship between the measured insulation resistance and the electrical conductivity of the coolant so that a separate measurement of the electrical conductivity by means of corresponding sensor systems and evaluation means can be dispensed with in the present invention.
    Type: Grant
    Filed: January 22, 2002
    Date of Patent: December 14, 2004
    Assignee: Ballard Power Systems AG
    Inventors: Anton Sonntag, Josef Sonntag, Hubert Urban