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
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.
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.
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.
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
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.
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
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
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
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
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.
Abstract: 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.
Abstract: A power converter utilizes a high frequency capacitor and a bulk capacitor coupled across the DC terminals to reduce high frequency effect and voltage overshoot, leading to space and cost savings in power converter design. Each capacitor may be physically coupled adjacent the gate driver board via clips, clamps, and/or fasteners.
Type:
Application
Filed:
September 17, 2003
Publication date:
November 18, 2004
Applicant:
Ballard Power Systems Corporation
Inventors:
Ajay V. Patwardhan, Douglas K. Maly, Sayeed Ahmed, Fred Flett
Abstract: A dual power module 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:
Application
Filed:
August 14, 2003
Publication date:
November 18, 2004
Applicant:
Ballard Power Systems Corporation
Inventors:
Sayeed Ahmed, Fred Flett, Ajay V. Patwardhan, Douglas K. Maly
Abstract: A power module employs at least one capacitor electrically coupled across the input terminals to reduce voltage overshoot. The capacitor may be surface mounted to a high side collector plating area and a low side emitter plating area.
Type:
Application
Filed:
August 14, 2003
Publication date:
November 18, 2004
Applicant:
Ballard Power Systems Corporation
Inventors:
Douglas K. Maly, Sayeed Ahmed, Ajay V. Patwardhan, Fred Flett
Abstract: Systems and methods for controlling and/or calculating the torque for a field oriented induction motor operating at a given stator frequency. The systems and methods include calculating the torque using a first algorithm when the motor is at or below a first predetermined stator frequency, a second algorithm when the motor is at or above a second predetermined stator frequency, and a third algorithm when the motor is between the first predetermined stator frequency and the second predetermined stator frequency.
Type:
Grant
Filed:
November 12, 2002
Date of Patent:
November 9, 2004
Assignee:
Ballard Power Systems Corporation
Inventors:
Li Chen, Xingyi Xu, Vinod Reddy, Richard J. Hampo, Kerry E. Grand
Abstract: Methods and systems for use with an electric machine which reduce magnetic leakage paths, improve d-axis flux, and/or reduce stress levels at high operating speeds.
Type:
Application
Filed:
December 8, 2003
Publication date:
November 4, 2004
Applicant:
Ballard Power Systems Corporation
Inventors:
Philip H. Mellor, Timothy J. Allen, David Seniawski, Raymond Ong
Abstract: An electrical connector for use in a power module includes a first end portion for forming an electrical connection with a substrate, a second end portion, and a compliant portion situated between the first end portion and the second end portion. The compliant portion includes a compressed position and a decompressed position. The first end portion is configured for forming an electrical connection with a substrate if the compliant portion is in the compressed position.
Type:
Grant
Filed:
September 20, 2001
Date of Patent:
September 21, 2004
Assignee:
Ballard Power Systems Corporation
Inventors:
Scott Parkhill, Sayeed Ahmed, Fred Flett
Abstract: A start-up circuit for converters with controller power supply connected at output side. With this start-up circuit, all the control and supporting circuitries are connected at the converter output low voltage side and protected from high input DC voltage. After the converter is started and the controller starts generating normal switching pulses, the start-up circuit may be disabled.
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.