Abstract: A method for decoupling a harmonic signal from an input signal wherein the harmonic signal is harmonic relative to a signal other than the input signal. An angular position of the other signal is multiplied by a value representing the harmonic to obtain an angular position multiple. A harmonic decoupling block uses the angular position multiple to obtain correction signals representing the harmonic signal, and subtracts the correction signals from the input current to decouple the harmonic signal from the input signal. This method is useful for decoupling unwanted harmonics from currents into which high-frequency signals have been injected for control of electric motors.

Abstract: Methods and apparatus are provided for controlling a stand-alone four-leg three-phase inverter. The inverter three-phase output is converted from AC domain elements to corresponding DC domain elements. The DC domain elements are processed into combined regulating and imbalance compensating signals, including over-current limiting. The compensating signals are restored to corresponding AC domain signals, and are processed into control inputs for the inverter, in order to stabilize the inverter output when connected to an unbalanced load. The inverter controller can be implemented entirely in software as a control algorithm.

Abstract: Methods and apparatus are provided for controlling an inverter with an under-damped L-C filter connected to a load. Samples of the inverter output are processed to generate voltage regulation signals and damping signals. The voltage regulation signals include both regulating and imbalance compensating elements, and are further modified by the damping signals. The modified voltage regulation signals control the switching circuits of the inverter to stabilize the inverter output to the load.

Abstract: An induction machine includes a rotor having rotor flux and a rotor resistance. The induction machine outputs first and second reference current values. A control system includes a first controller that outputs first and second reference voltage values to the induction machine and that generates an estimated rotor flux magnitude value based on a rotor resistance parameter. A computation circuit receives the first and second reference current values from the induction machine and the first and second voltage reference values from the first controller and calculates an actual rotor flux magnitude. A rotor resistance adjustor that updates the rotor resistance parameter based on the actual and estimated rotor flux magnitudes.

Abstract: A multiple inverter system is powered from a common energy source such as a battery. First and second inverters are coupled to the common energy source and drive corresponding motors. First and second controllers provide pulse width modulated signals, modulated with respect to first and second clock signals, respectively, to the respective first and second inverters. A capacitor coupled between a power bus and a ground bus smoothes power bus ripples caused by simultaneous switching. To reduce the size needed for the capacitor, different modulation schemes, such as center based interleaved, and leading and lagging edge coincident, are used when both motors are in the motoring mode or both motors are in the regeneration mode. However, the same modulation scheme is used when one motor is in the motoring mode and the other motor is in the regeneration mode.

Abstract: Methods and apparatus are provided for an electric vehicle embodying an axial flux traction motor directly coupled to a wheel thereof. The traction motor comprises a stator having coils for producing a magnetic field, an annular rotor magnetically coupled to the stator and mechanically to an output shaft. Permanent magnets of alternating polarity are mounted on the annular rotor. Magnetic shunts bridge a portion of the stator slots above the coils. The magnets are arranged in groups with group-to-group spacing exceeding magnet-to-magnet spacing. Adjacent edges of the magnets diverge. The method comprises, looking up d- and q-axis currents to provide the requested torque and motor speed for the available DC voltage, combining at least one of the d- and q-axis currents with a field weakening correction term, converting the result from synchronous to stationary frame and operating an inverter therewith to provide current to the coils of the motor.

Abstract: An induction machine includes a rotor having rotor flux and a rotor resistance. The induction machine outputs first and second reference current values. A control system includes a first controller that outputs first and second reference voltage values to the induction machine and that generates an estimated rotor flux magnitude value based on a rotor resistance parameter. A computation circuit receives the first and second reference current values from the induction machine and the first and second voltage reference values from the first controller and calculates an actual rotor flux magnitude. A rotor resistance adjustor that updates the rotor resistance parameter based on the actual and estimated rotor flux magnitudes.

Abstract: A drive system that is suitable for high bandwidth current control of a three-phase voltage source inverter in the overmodulation region includes a feedback path that has a harmonic decoupling block that subtracts selected harmonic components from signals representative of a corresponding motor phase current signal. The harmonic decoupling block thereby generates corrected feedback signals. The drive system also includes subtractor blocks that subtract the corrected feedback signals from signals representative of open-loop magnetizing reference currents to generate difference signals. Also included is a modulation block that utilizes the difference signals to produce signals to drive a three-phase voltage source inverter in an overmodulated six-step mode.

Abstract: The present invention includes a method for thermal management in a voltage source inverter. The method includes sensing a low output frequency condition, determining a zero vector modulation responsive to the sensed low output frequency condition, and applying the determined zero vector modulation to reduce thermal stress in the voltage source inverter. The step of determining the zero vector modulation responsive to the sensed low output frequency condition includes mapping an output voltage requirement to a space vector structure and determining state switching space vectors based on the mapped output voltage requirement.

Abstract: A multiple inverter system is powered from a common energy source such as a battery. First and second inverters are coupled to the common energy source and drive corresponding motors. First and second controllers provide pulse width modulated signals, modulated with respect to first and second clock signals, respectively, to the respective first and second inverters. A capacitor coupled between a power bus and a ground bus smoothes power bus ripples caused by simultaneous switching. To reduce the size needed for the capacitor, different modulation schemes, such as center based interleaved, and leading and lagging edge coincident, are used when both motors are in the motoring mode or both motors are in the regeneration mode. However, the same modulation scheme is used when one motor is in the motoring mode and the other motor is in the regeneration mode.

Abstract: A method of generating low voltage auxiliary power forms for electric or hybrid vehicle use by tapping power from the traction motor primary winding with a secondary winding and rectifier.

Abstract: An electric motor control system including a stator for producing a magnetic field, a surface mount permanent magnet rotor rotated by the magnetic field, a motor shaft coupled to the rotor, power electronics for controlling the magnetic field in the stator, and where the power electronics controls the q-axis and d-axis current components for the electric motor.

Abstract: A method of generating low voltage auxiliary power forms for electric or hybrid vehicle use by tapping power from the traction motor primary winding with a secondary winding and rectifier.

Abstract: A control scheme for an surface-mounted permanent-magnet synchronous (SMPMS) drive uses a combination of an open-loop magnetizing current reference calculation and a stabilizing feedback term, which speeds-up the torque transient response. The feedback term increases the stability margin during torque transients by increasing the available voltage margin for current control. The magnetizing current reference calculation takes into account the saturation effects in the SMPMS drive, which occur at peak torque points, and compensates for them. By taking into account saturation effects, stable operation at high speed is achieved, thereby increasing the speed range of the SMPMS drive.

Abstract: A control scheme for an surface-mounted permanent-magnet synchronous (SMPMS) drive uses a combination of an open-loop magnetizing current reference calculation and a stabilizing feedback term, which speeds-up the torque transient response. The feedback term increases the stability margin during torque transients by increasing the available voltage margin for current control. The magnetizing current reference calculation takes into account the saturation effects in the SMPMS drive, which occur at peak torque points, and compensates for them. By taking into account saturation effects, stable operation at high speed is achieved, thereby increasing the speed range of the SMPMS drive.

Abstract: A control system and method for use in controlling a torque-controlled permanent magnet synchronous motor drive. A slew-rate limiter processes an input torque command to produce a modified torque command that is input to the motor drive. A controller is coupled to the slew-rate limiter and the motor drive for dynamically limiting the input torque command applied to the motor drive and its rate of increase. The slew rate limiter processes an applied torque command to output a modified torque command that is applied to the motor drive. Current control error signals are output by the motor drive. The RMS value of the current control error signals is computed. The RMS value is compared to low and high thresholds. If the RMS value is greater than the high threshold, the modified torque command is reduced until the RMS value is less than the high threshold.

Abstract: A control system and method for controlling an inverter used in an electric vehicle. The control system and method measures an average DC bus voltage and compares it to low voltage and high voltage thresholds defining predetermined conditions. If the voltage conditions are satisfied, the six-step mode is enabled based upon an applied torque command. Thus, if the torque command is higher than a high torque threshold, the six-step mode indefinitely enabled, and if the torque command is below the high torque threshold, the six-step mode is enabled for a limited time duration, and then disabled.

Abstract: A surface-mounted permanent magnet synchronous machine drive and a method of controlling the machine drive. Flux weakening and current regulating loops cooperate to provide automatic transition to the flux weakening mode (operation above base speed), regardless of DC bus voltage, load or other operating conditions. The modulation index (d) is used as a condition for automatic start of flux weakening operation is very useful because this point can be easily changed by software when necessary, regardless of the value of DC bus voltage. This feature provides significant performance improvement. No look-up tables are used in the flux weakening loop. The on-set point for flux weakening is automatically adjusted, and may be changed through software. An appropriate d-axis current component is injected over the entire speed range, providing the maximum available torque (which corresponds to the q-axis current component).

Abstract: An electric power system for an electric vehicle includes an electric drive motor, a high voltage bus for supplying operating power to energize the drive motor, and an inverter including power switching devices and having an inverter output. The inverter is coupled between the high voltage bus and the electric drive motor and a controller is coupled to the inverter and provides motor control signals and high frequency injection signals to the inverter. An auxiliary power unit is coupled to the inverter output and has a DC output for supplying DC operating power. The auxiliary power unit supplies DC power in response to the high frequency injection signals. The electric drive motor operates in response to the motor control signals and is substantially unaffected by the high frequency injection signals.

Abstract: A control algorithm or method for use in controlling a voltage-fed induction machine. The control algorithm includes the following steps. The DC link voltage supplied to an inverter driving the induction machine is monitored. When the DC link voltage is high enough, the algorithm controls the amount of current supplied to the induction machine to provide current controlled operation of the induction machine. When the DC link voltage is not high enough to control the current under transient conditions, the induction machine is controlled by imposing the maximum possible phase voltage and optimal slip angle on the machine to provide maximal torque per ampere operation of the induction machine. The maximal torque per ampere operation is performed when either of the following conditions is met: a) the torque level required by the induction machine is such that efficiency optimization cannot be performed, or b) current regulators approach saturation.