Abstract: This invention relates to a variable speed drive with synchronous AC motor. In the disclosed embodiment, a variable speed drive operates in three modes: a first predetermined mode, in which a function (e.g., trapezoidal current waveform) controls operation at low motor speeds; a transitional mode, in which a transition function is applied to anticipate transitions of the first function, thus causing a smoothing of transitions at higher speeds; and a second predetermined (e.g., sinusoidal or smoothly-varying current) waveform at high speeds. This allows for the reduction in required rotor position sensor resolution as compared to conventional synchronous variable speed drives, resulting in cost savings in the sensor device and associated wiring. Additionally, it is quieter and more efficient operation at high speed as compared to conventional trapezoidal-current/DC-brushless motor drives.

Abstract: An electric motor is provided with active hysteresis-based control of winding current. The motor has an efficient stator winding arrangement, as well as at least one adjustable air gap. Also provided is a stator, windings and air gap adjustment mechanism, as well as a method and system for controlling the torque produced by the motor using active hysteresis-based control of the motor's winding currents. The stator has its windings distributed among arc sections, the windings in each arc section being associated with only one phase of the motor. The hysteresis-based control of winding current is active in that a bandwidth or spread of the hysteresis band is adjusted depending on at least one of several selectively determined factors. The motor and its associated components are particularly well-suited for use in an electrically powered vehicle, as well as in hybrid vehicles using both electric power from a battery and electric power derived from a fuel-burning engine.

Abstract: An electric motor is provided with active hysteresis-based control of winding current. The motor has an efficient stator winding arrangement, as well as at least one adjustable air gap. Also provided is a stator, windings and air gap adjustment mechanism, as well as a method and system for controlling the torque produced by the motor using active hysteresis-based control of the motor's winding currents. The stator has its windings distributed among arc sections, the windings in each arc section being associated with only one phase of the motor. The hysteresis-based control of winding current is active in that a bandwidth or spread of the hysteresis band is adjusted depending on at least one of several selectively determined factors. The motor and its associated components are particularly well-suited for use in an electrically powered vehicle, as well as in hybrid vehicles using both electric power from a battery and electric power derived from a fuel-burning engine.

Abstract: A method and an apparatus for efficiently controlling the power output of a solar cell array string or a plurality of solar cell array strings to achieve a maximum amount of output power from the strings under varying conditions of use. Maximum power output from a solar array string is achieved through control of a pulse width modulated DC/DC buck converter which transfers power from a solar array to a load or battery bus. The input voltage from the solar array to the converter is controlled by a pulse width modulation duty cycle, which in turn is controlled by a differential signal comparing the array voltage with a control voltage from a controller. By periodically adjusting the control voltage up or down by a small amount and comparing the power on the load or bus with that generated at different voltage values a maximum power output voltage may be obtained.