Abstract: A hydrogen fuel cell system (100) for charging a battery (116) of an electric vehicle, includes at least one tank (102) for storing hydrogen under pressure. A combined heat exchanger and air engine (104) expands the pressurized hydrogen and converts the expanding hydrogen into mechanical energy. A plurality of fuel cells (106) receive the expanded hydrogen for supplying heat to the heat exchanger and air engine (104) and supplying a first current for charging the battery (116). A generator (108) generates a multi-phase voltage in response to the mechanical energy. A electrical power converter (110) responsive to the multi-phase voltage provides a second current for charging the battery (116).

Abstract: A hydrogen fuel cell system (100) for charging a battery (116) of an electric vehicle, includes at least one tank (102) for storing hydrogen under pressure. A combined heat exchanger and air engine (104) expands the pressurized hydrogen and converts the expanding hydrogen into mechanical energy. A plurality of fuel cells (106) receive the expanded hydrogen for supplying heat to the heat exchanger and air engine (104) and supplying a first current for charging the battery (116). A generator (108) generates a multi-phase voltage in response to the mechanical energy. A electrical power converter (110) responsive to the multi-phase voltage provides a second current for charging the battery (116).

Abstract: Methods and apparatus are provided for monitoring a coolant conductivity of a fuel cell supplying power via positive and negative buses. The method includes measuring a first voltage of the positive bus, measuring a second voltage of the negative bus, applying a resistance between the positive bus and a reference potential, measuring a third voltage of the positive bus after a period of applying the resistance, and determining an isolation resistance based on the measured voltages. The isolation resistance is a function of the coolant conductivity.

Abstract: Methods and apparatus are provided for monitoring a coolant conductivity of a fuel cell supplying power via positive and negative buses. The method includes measuring a first voltage of the positive bus, measuring a second voltage of the negative bus, applying a resistance between the positive bus and a reference potential, measuring a third voltage of the positive bus after a period of applying the resistance, and determining an isolation resistance based on the measured voltages. The isolation resistance is a function of the coolant conductivity.

Abstract: A method of starting a permanent magnet machine. A machine stator voltage in a stationary reference frame is sensed. An initial speed of a rotor of the machine is estimated based on the sensed voltage, and state variables of control algorithms are initialized based on the estimated initial speed. This method can provide smooth startup and/or restart at any speed.

Abstract: The present invention includes a method for managing processor execution time in a motor controller. The method includes receiving motor speed data, comparing the received motor speed data to predetermined motor speed ranges, determining a motor speed range based on the comparison, and modulating an inverter switching frequency of the motor controller processor based on the motor speed range. The step of receiving motor speed data may include receiving machine terminal information, processing the received machine terminal information utilizing a sensorless control algorithm, and determining motor speed data based on the processed information. The step of modulating the inverter switching frequency may include determining a modified inverter switching frequency value based on the determined motor speed range and providing the modified inverter switching frequency value to a processor control algorithm.

Abstract: A method of reducing loss in an interior permanent magnet drive system is provided. A current input DC link power value is calculated. The current input DC link power value is then compared with a previous input DC link power value. A change in input DC link power value is determined from this comparison. A flux decrement value is calculated. The flux decrement value is based on the change in input DC link power value. A stator current value is generated. The stator current value is based on the flux decrement value. Finally, the stator flux current is reduced, based on the stator current value.

Abstract: A device for implementing a method for predicting rotational positions of a rotating shaft is disclosed. A motor shaft is rotated over a range of rotation. The device detects each incremental rotation position of the motor shaft from a set of incremental rotational positions being spaced by a fixed increment. Prior to a change in the rotational speed of the motor shaft, the device generates a prediction of each rotational position. When a detected incremental rotation indicates a change in rotational speed of the motor shaft, the device modifies the prediction of each motor shaft position in a continuous manner.

Abstract: A device for implementing a method for predicting rotational positions of a rotating shaft is disclosed. A motor shaft is rotated over a range of rotation. The device detects each incremental rotation position of the motor shaft from a set of incremental rotational positions being spaced by a fixed increment. Prior to a change in the rotational speed of the motor shaft, the device generates a prediction of each rotational position. When a detected incremental rotation indicates a change in rotational speed of the motor shaft, the device modifies the prediction of each motor shaft position in a continuous manner.

Abstract: A method of reducing loss in an interior permanent magnet drive system is provided. A current input DC link power value is calculated. The current input DC link power value is then compared with a previous input DC link power value. A change in input DC link power value is determined from this comparison. A flux decrement value is calculated. The flux decrement value is based on the change in input DC link power value. A stator current value is generated. The stator current value is based on the flux decrement value. Finally, the stator flux current is reduced, based on the stator current value.

Abstract: A control system for an interior permanent magnet motor which includes five regulators to provide efficient control of the motor. Deviation from a desired maximum torque per amp trajectory is minimized by making two of the five regulators field-weakening regulators. First and second regulators provide current control of the quadrature-axis current and direct-axis current, respectively. A limiter limits the direct-axis current from exceeding the maximum allowed stator current and any excess current is added to the quadrature-axis current. Fourth and fifth regulators are field-weakening regulators. The fourth regulator generates a first field-weakening signal that increases the direct-axis signal when the quadrature-axis voltage approaches a desired maximum voltage. The fifth regulator generates a second field-weakening signal that decreases the quadrature-axis current signal when the direct-axis voltage approaches a desired maximum voltage.

Abstract: The absolute position of a rotor of a permanent magnet motor is determined by detecting an angular position of a direct axis of the rotor; and detecting a polarity of the rotor to determine the absolute position of the rotor. The polarity of the rotor may be determined by applying a square wave voltage to phase windings of a stator of the motor to generate an mmf vector parallel to the direct axis, measuring phase currents of the phase windings, determining a direct axis current responsive to the measured phase currents and the angular position, determining that the rotor is aligned with the mmf vector if the direct axis current is shifted positive, and determining that the rotor is aligned 180 degrees out of phase with the mmf vector if the direct axis current is shifted negative.

Abstract: Power-generating apparatus and a voltage generation method employing null vector modulation for use with an electric vehicle. A DC power supply voltage is provided or generated from a power source and is inverted by a three-phase inverter to generate three phase AC that is supplied to an AC motor or load. One phase of the three phase AC is filtered and transformed by a DC rejection capacitor and single phase transformer of an auxiliary power supply to generate an AC voltage. The AC voltage is rectified and filtered by a rectifier and low pass filter of the auxiliary power supply to produce a DC output voltage. The one phase of the three phase AC and the DC output voltage are processed by a controller to control frequencies of null line-to-line zero voltage vectors during inversion so that the transformed AC voltage does not affect or is not seen by the AC motor or load. This allows for independent control of the voltage at the output of the auxiliary power supply.

Abstract: A position sensorless interior permanent magnet drive system and methods for use in electric and hybrid electric vehicles. The interior permanent magnet drive system and method use two rotor position estimation techniques for low and high speed operation and an initial rotor magnet polarity detection technique used at stand-still conditions. The use of the two different rotor position estimation techniques in combination enhances system efficiency and accuracy.