Patents Assigned to Ballard Power Systems Corporation
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Publication number: 20080013347Abstract: 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: ApplicationFiled: July 2, 2007Publication date: January 17, 2008Applicant: BALLARD POWER SYSTEMS CORPORATIONInventors: Duo Deng, Anil Tuladhar, Kent Harmon
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Patent number: 7256566Abstract: 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: GrantFiled: April 30, 2004Date of Patent: August 14, 2007Assignee: Ballard Power Systems CorporationInventors: Vijay Bhavaraju, Kerry E. Grand, Anil Tuladhar
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Patent number: 7193860Abstract: A DC bus for use in a power module has a positive DC conductor bus plate parallel with a negative DC conductor bus plate. One or more positive leads are connected to the positive bus and are connectable to a positive terminal of a power source. One or more negative leads are connected to the negative bus and are connectable to a negative terminal of a power source. The DC bus has one or more positive connections fastenable from the positive bus to the high side of a power module. The DC bus also has one or more negative connections fastenable from the negative bus to the low side of the power module. 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: GrantFiled: December 2, 2005Date of Patent: March 20, 2007Assignee: Ballard Power Systems CorporationInventors: Scott Parkhill, Sayeed Ahmed, Fred Flett
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Patent number: 7190145Abstract: A method and apparatus for improving speed measurement quality in systems having multi-pole machines is taught. The method compensates for pole misalignment by computing speed based upon moving average techniques. In one embodiment, a moving average speed averaged over a complete interval of rotation is determined, based upon measurements of one or more magnetic pole position sensors for magnetic pole location. In another embodiment, a time interval between two poles is averaged over one or more rotational periods, and the average time interval is used to determine the moving average speed. Computation of the moving average speed reduces errors in speed measurements due to pole misalignment and may provide for smaller control adjustment times for controlling motor speed variability. In one embodiment, the speed measurement system includes a multi-pole rotor, and a controller having a capture timer and a buffer.Type: GrantFiled: December 30, 2002Date of Patent: March 13, 2007Assignee: Ballard Power Systems CorporationInventors: Kerry E. Grand, Richard J. Hampo, Yifan Zhao
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Patent number: 7187558Abstract: A DC bus for use in a power module has a positive DC conductor bus plate parallel with a negative DC conductor bus plate. One or more positive leads are connected to the positive bus and are connectable to a positive terminal of a power source. One or more negative leads are connected to the negative bus and are connectable to a negative terminal of a power source. The DC bus has one or more positive connections fastenable from the positive bus to the high side of a power module. The DC bus also has one or more negative connections fastenable from the negative bus to the low side of the power module. 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: GrantFiled: October 6, 2005Date of Patent: March 6, 2007Assignee: Ballard Power Systems CorporationInventors: Scott T. Parkhill, Sayeed Ahmed, Fred Flett
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Patent number: 7178412Abstract: An encoder failure detector system and method for detecting failure of an encoder at near-zero rotational speeds. For example, in one embodiment a failure is indicated if a torque command exceeds a selected threshold for a selected period of time and no movement of a rotor is detected during the selected period of time.Type: GrantFiled: July 30, 2004Date of Patent: February 20, 2007Assignee: Ballard Power Systems CorporationInventor: Venkatapathi Raju Nallapa
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Patent number: 7180763Abstract: A power converter comprising a DC/AC bridge circuit electrically coupled between positive and negative DC bus terminals and a set of phase terminals, a DC/DC bridge circuit electrically coupled to the positive and negative DC bus terminals and a set of DC bridge terminals. The power converter may be configured to control the transfer of power to and/or from the DC bridge terminals and to control the transfer of power to and/or from the AC phase terminals.Type: GrantFiled: September 21, 2004Date of Patent: February 20, 2007Assignee: Ballard Power Systems CorporationInventors: Ajay V. Patwardhan, Douglas K. Maly, Fred Flett, Sayeed Ahmed, Pablo Rodriguez, Kanghua Chen, Gerardo Jimenez
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Patent number: 7177165Abstract: Independent phase output voltage control for a 3-phase 4-wire DC/AC inverter, for example, is provided. With the independent phase output voltage control, all three phase output voltages from the DC/AC inverter can be separately and effectively controlled to provide balanced 3-phase voltages from the DC/AC inverter to an unbalanced load, and/or to provide unbalanced 3-phase voltages from the DC/AC inverter to a balanced or unbalanced load. The independent phase output voltage control method can be applied to an inverter power system, with outputs of N-phase (N+1) wire configurations. Here, N can be any integer number greater than zero.Type: GrantFiled: June 21, 2004Date of Patent: February 13, 2007Assignee: Ballard Power Systems CorporationInventors: Duo Deng, Kon-King M. Wang
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Patent number: 7158395Abstract: 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: GrantFiled: April 30, 2004Date of Patent: January 2, 2007Assignee: Ballard Power Systems CorporationInventors: Duo Deng, Anil Tuladhar, Kenneth J. Farkas, Kerry E. Grand
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Publication number: 20060274561Abstract: A tri-level inverter power module has an architecture employing a high degree of modularity that allows a base power module to be quickly, easily, and cost effectively configured to address a large variety of applications.Type: ApplicationFiled: September 9, 2003Publication date: December 7, 2006Applicant: Ballard Power Systems CorporationInventors: Sayeed Ahmed, Fred Flett, Ajay Patwardhan, Douglas Maly
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Patent number: 7106564Abstract: Devices and methods for detecting islanding operation of a static power source involve injection of a non-harmonic error on the phase angle of the static power source in regular steps to introduce a very small intentional phase shift for the output voltage of the static power source in every voltage cycle which is corrected in each cycle in synchronization with the grid voltage in normal operation of the grid. In abnormal operation of a grid loss, this intentional small phase shift or error causes an intentional small frequency drift in each voltage cycle that continues in one cycle after another cycle. When the intentional frequency drift is over a preset level, a detection circuit starts to isolate the static power source from the grid to prevent islanding operation.Type: GrantFiled: December 23, 2002Date of Patent: September 12, 2006Assignee: Ballard Power Systems CorporationInventors: Duo Deng, Anil Tuladhar
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Patent number: 7098569Abstract: A rotor assembly for use in an electric motor or generator where the mass of the rotor assembly is reduced with respect to conventional rotor assemblies. In addition, the rotor assembly is configured to be scalable to different sized electric motors. Within the rotor assembly, the rotor hub, the shaft, and the permanent magnets can independently or collectively be modified to have a reduced mass. In one aspect, a portion of the rotor hub adjacent to the shaft is configured with passages and spokes. In another aspect, an intermediate hub with lightening holes is provided between the shaft and the rotor hub. In yet another aspect, a large diameter hollow shaft replaces a portion of the rotor hub. In yet another aspect, the permanent magnets are configured to have an arc-shape, which permits the thickness of the magnets to be reduced without reducing the efficiency of the magnets.Type: GrantFiled: August 26, 2004Date of Patent: August 29, 2006Assignee: Ballard Power Systems CorporationInventors: Raymond Ong, Timothy J. Allen, Roy I. Davis, Tod R. Tesch
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Patent number: 7084588Abstract: A control subsystem for an electric motor determines whether power was interrupted, and delays torque production if power was interrupted. The control subsystem may employ two separate non-volatile memory locations, or alternatively a single non-volatile memory location.Type: GrantFiled: July 30, 2004Date of Patent: August 1, 2006Assignee: Ballard Power Systems CorporationInventors: Richard J. Hampo, Venkatapathi R. Nallapa, Christophe Soudier
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Patent number: 7071759Abstract: Techniques for determining root mean square (RMS) values of a signal for controlling operation of grid-linked converters, such as DC-to-AC inverters, via squaring the signal, sampling the squared signal n times during a cycle period to obtain n samples, summing the first n?1 samples to obtain a first value, multiplying the first value by a sampling time and a frequency of the signal to obtain a second value, determining a compensation factor, adding the compensation factor to the second value to obtain a third value, and determining a square root of the third value to obtain a RMS result.Type: GrantFiled: March 9, 2004Date of Patent: July 4, 2006Assignee: Ballard Power Systems CorporationInventor: Anil Tuladhar
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Patent number: 7058755Abstract: An efficient emulation of EEPROM employing flash memory employs a fixed location for an address pointer in flash memory and such that an erase operation is required only once every nth update where n is the number of bits at the fixed location, thus avoiding the need to erase the sector on every update and avoiding delays associated with linked lists for determining the address of the most up-to-date information. Use of bit shifting provides fast determination of the desired address.Type: GrantFiled: September 9, 2003Date of Patent: June 6, 2006Assignee: Ballard Power Systems CorporationInventor: Venkatapathi R. Nallapa
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Patent number: 7046535Abstract: Power converters such as power modules configured as inverters employ modularized approaches. In some aspects, semiconductor devices are thermally coupled directly to thermally conductive substrates without intervening dielectric or insulative structures. Additionally, or alternatively, semiconductor devices are thermally coupled to thermally conductive substrates with relatively large surface areas before heat transferred from the semiconductor devices encounters a dielectric or electrically insulating structure with correspondingly high thermal impedance.Type: GrantFiled: December 3, 2004Date of Patent: May 16, 2006Assignee: Ballard Power Systems CorporationInventors: Pablo Rodriguez, Douglas K. Maly, Ajay V. Patwardhan, Kanghua Chen, Sayeed Ahmed, Gerardo Jimenez, Fred Flett
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Publication number: 20060072263Abstract: Cycle error correction is performed in an electronic power system to compensate for a difference between an AC grid side frequency and an AC load side frequency. The electronic power system can comprise an electronic power inverter, such as one usable with an uninterruptible power supply. Cycles of signals indicative of the AC grid power and the AC load power are counted and compared to obtain a cycle error value. If the cycle error value exceeds a first value to indicate that AC load side frequency is too high or too low, then compensation is performed to change the AC load side frequency to be closer to the AC grid side frequency. If the cycle error value falls below a second value to indicate that the AC grid side frequency and AC load side frequency are sufficiently close to one another, then the compensation is deactivated.Type: ApplicationFiled: October 1, 2004Publication date: April 6, 2006Applicant: Ballard Power Systems CorporationInventors: Duo Deng, Kenneth Farkas, Anil Tuladhar, Kerry Grand
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Patent number: 7019996Abstract: A power converter may employ a planar transformer to minimize winding conduction loss, and the switching devices of the power converter may be aligned in lines parallel to an edge of the planar transformer to minimize the termination leakage inductance. The windings of the planar transformer may be thermally conductively coupled to one or more heat sinks carried by a circuit board which are with respective ones of the switching devices, to provide a cooling path for the planar transformer.Type: GrantFiled: October 16, 2003Date of Patent: March 28, 2006Assignee: Ballard Power Systems CorporationInventors: Lizhi Zhu, John M. Van Dyke, Richard J. Hampo
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Patent number: 7014928Abstract: Fuel cell systems and control methods including a fuel cell and a second energy source, such as a battery that is adapted to supplement the fuel cell. In addition, the fuel cell system utilizes a single bipolar switching module, such as an IGBT six pack module that is configured to implement a DC/DC converter, such as a DC/DC boost converter, for both the fuel cell and the battery. The fuel cell system also makes use of a controller that is configured to control either or both of input current and output voltage of the DC/DC converter.Type: GrantFiled: January 16, 2003Date of Patent: March 21, 2006Assignee: Ballard Power Systems CorporationInventors: Christos A. Kambouris, John T. Bates
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Patent number: 7012822Abstract: Integrated power conversion systems and methods for use in an electric vehicle having an electric motor, a primary high-voltage energy source, and an auxiliary energy source including a traction inverter module operable for converting a DC current generated by the high-voltage energy source into an AC current capable of powering the electric motor, and a DC/DC converter operable to step-down a voltage of the high-voltage energy source or step-up a voltage of the auxiliary energy source, wherein the traction inverter module and the DC/DC converter may share one or more common components, such as a common high-voltage DC bus capacitor, a common DC bus bar, and/or a common high-voltage transistor.Type: GrantFiled: February 7, 2003Date of Patent: March 14, 2006Assignee: Ballard Power Systems CorporationInventors: Lizhi Zhu, Xingyi Xu