Abstract:
A controllable switching mechanism (100) integrally housed within a motor (100) to optimally couple the windings (112, 114, 116) of an AC motor for improved torque-speed characteristics. The switching mechanism (100) includes a plurality of double throw switches (121, 123, 125) each with a first and second closed position. The first closed position results in connecting the windings (112, 114, 116) of the AC motor (102) in one configuration for improved torque at lower rotor speeds. The second closed position results in connecting the windings (112, 114, 116) of the AC motor (102) in another configuration for improved torque at higher speeds. The winding configurations may be wye for lower speeds and delta for higher speeds. An accompanying controller (104), based on various inputs, optimally senses the best time for switching between configurations and sends appropriate control signals to the switching mechanism (100) housed with the AC motor (102).
Abstract:
A voltage source inverter generating a poly phase AC signal is provided that includes an SVPWM controller. The controller is adapted to modify the switching pattern at low sine-wave frequencies creating a more even distribution of the conduction losses. The switching pattern periodically changes the sequence (or rotational sense) of the space vector components from clock-wise to counter-clock-wise direction, and vice-versa.