Abstract: An improved switching apparatus and method are disclosed. In at least some embodiments, the apparatus includes first and second ports, a first switching device such as a contactor coupled between the ports, and a second switching device coupled in parallel with the contactor between the ports, where the second switching device can be or include a solid-state semiconductor device. The second switching device is operated to become conductive at a first time prior to a second time when the contactor switches between a conductive state and a non-conductive state, and remains conductive up to a third time subsequent to the second time. In at least some further embodiments, the apparatus also includes one or both of a voltage sensing capability and a current sensing capability and switches the second switching device to become conductive based upon voltage and/or current information.

Abstract: Control systems and speed estimation systems are presented having a transient-based speed estimation system that provides a rotor speed estimate based on a measured speed-related motor transient signal, and a transient excitation system which selectively modifies at least one switch control signal to excite the measured motor transient.

Abstract: Systems, methods, and devices are disclosed, including an induction-motor controller that has a motor controller configured to receive alternating current (AC) power with a voltage that varies generally sinusoidally and transmit the AC power during a conduction angle of a cycle of the AC power. In some embodiments, the conduction angle varies generally sinusoidally at a lower frequency than the AC power, and the motor controller may be configured to not transmit the AC power outside of the conduction angle.

Abstract: Systems, methods, and devices are disclosed, including an induction-motor controller having a phase path; a solid-state switch interposed on the phase path; and a controller coupled to the solid-state switch. In certain embodiments, the controller is configured to switch the solid-state switch so that the solid-state switch is conductive during a conduction angle of a cycle of an incoming AC power waveform conveyed by the phase path, calculate the conduction angle based on a generally sinusoidal reference value that has a frequency lower than a frequency of the incoming AC power waveform, and adjust the generally sinusoidal reference value based on a value indicative of flux in a load coupled to the phase path.

Abstract: An improved switching apparatus and method are disclosed. In at least some embodiments, the apparatus includes first and second ports, a first switching device such as a contactor coupled between the ports, and a second switching device coupled in parallel with the contactor between the ports, where the second switching device can be or include a solid-state semiconductor device. The second switching device is operated to become conductive at a first time prior to a second time when the contactor switches between a conductive state and a non-conductive state, and remains conductive up to a third time subsequent to the second time. In at least some further embodiments, the apparatus also includes one or both of a voltage sensing capability and a current sensing capability and switches the second switching device to become conductive based upon voltage and/or current information.

Abstract: Control systems and speed estimation systems are presented having a transient-based speed estimation system that provides a rotor speed estimate based on a measured speed-related motor transient signal, and a transient excitation system which selectively modifies at least one switch control signal to excite the measured motor transient.

Abstract: AC motor control systems and speed controllers are presented, including a transient-based speed estimation system that provides a rotor speed estimate based on a measured speed-related motor transient signal, and a transient excitation system which selectively modifies at least one switch control signal to excite the measured motor transient. The measured speed-related transient may include a phase error signal, a phase lag signal, a peak current signal, a voltage integral signal, a motor winding voltage signal, a switching device voltage, and a voltage zero crossing signal, and the switching signal modification can comprise removal of select pulse(s) from a switching control pulse stream or selective modification of spacings between pulses to re-excite the motor transient.

Abstract: A method for starting an unexcited, multiple phase, alternating current induction motor rotating at an unknown speed is provided. The method includes generating an output signal with an AC drive at a predetermined frequency in order to energize the motor. The output signal has independently adjustable frequency and voltage components. A speed reference is provided which is functionally related to the frequency of the output signal. The voltage of the output signal is ramped at a predetermined rate and the frequency of the output signal is adjusted such that the voltage of the output signal equals the motor's set point and the speed reference is substantially equal to the speed of the motor. The motor then enters the normal operating mode.

Abstract: A DC braking system for an inverter-driven induction motor, (e.g., three-phase). When a braking command occurs, the normal gating sequence of the inverter stops. Mode 1 of the braking procedure starts. In Mode 1, two semiconductor phase switches of the group connected with one of the DC buses and the semiconductor switch of the third phase that is connected with the other DC bus are latched in a conducting state. The motor essentially receives DC current, which increases until it actuates a current limit device, clearing the latch. Then all six switches are turned off. That drives the motor current through the back-biased parallel diodes. The negative DC bus voltage is available to suppress motor current despite large motor speed voltages. The apparatus repeats the Mode 1 procedure for a predetermined time interval, after which Mode 2 of the braking procedure starts. In Mode 2, just as in Mode 1, two switches of one bus and one switch of another bus conduct until an overcurrent limit is reached.