Device for operating an electric motor, comprising a detection unit for detecting zero-crossings and phase angles of applied phase-shifted sinusoidal voltage phases of a multi-phase power supply network; and a switching unit for connecting half-waves of the applied sinusoidal voltage phases through by means of semiconductor switches in accordance with switching patterns applied to the semiconductor switches, said patterns being synchronised with the detected phase angles and zero-crossings, to generate phase-shifted quasi-sinusoidal voltage phases which are applied directly to the electric motor.

Device for operating an electric motor, comprising a detection unit for detecting zero-crossings and phase angles of applied phase-shifted sinusoidal voltage phases of a multi-phase power supply network; and a switching unit for connecting half-waves of the applied sinusoidal voltage phases through by means of semiconductor switches in accordance with switching patterns applied to the semiconductor switches, said patterns being synchronised with the detected phase angles and zero-crossings, to generate phase-shifted quasi-sinusoidal voltage phases which are applied directly to the electric motor.

Device for operating an electric motor, comprising a detection unit for detecting zero-crossings and phase angles of applied phase-shifted sinusoidal voltage phases of a multi-phase power supply network; and a switching unit for connecting half-waves of the applied sinusoidal voltage phases through by means of semiconductor switches in accordance with switching patterns applied to the semiconductor switches, said patterns being synchronised with the detected phase angles and zero-crossings, to generate phase-shifted quasi-sinusoidal voltage phases which are applied directly to the electric motor.

Exemplary embodiments or implementations are disclosed of methods, apparatus, and systems for operating motors in variable speed situations. In an exemplary implementation, a method of controlling a variable-speed motor includes defining a control duration as a predetermined number of cycles of a multiple-phase power supply. Each speed in a range of speeds is defined by a corresponding number of the cycles of the control duration. Power is provided to the motor from the power supply at a selected one of the speeds, by enabling input from the power supply for the number of the cycles of the control duration corresponding to the selected speed.

Exemplary embodiments or implementations are disclosed of methods, apparatus, and systems for operating motors in variable speed situations. In an exemplary implementation, a method of controlling a variable-speed motor includes defining a control duration as a predetermined number of cycles of a multiple-phase power supply. Each speed in a range of speeds is defined by a corresponding number of the cycles of the control duration. Power is provided to the motor from the power supply at a selected one of the speeds, by enabling input from the power supply for the number of the cycles of the control duration corresponding to the selected speed.

A control system for a 2-phase brushless AC motor comprises a position sensor for detecting a position of a rotor of the motor; a polarity detector for detecting a polarity of an AC supply for the motor; a first and second switching circuits respectively coupled to a first and second phase coils of the motor; a current sensor for detecting conduction of the first and second phase coils; and a controller for controlling conduction of the first and second switching circuits according to signals provided by the position sensor, the polarity detector and the current sensor; wherein the control system is embedded in the motor; and the controller is configured to turn on the first switching circuit at appropriate time interval in an AC cycle and turn on the second switching circuit to compensate for another time interval according to the position of the rotor.

A circuit for a motor comprises at least two phase windings forming one half of motor phase windings of the circuit and at least two other phase windings forming another half of the motor phase windings of the circuit. A direct current (DC) power supply receives alternating current (AC) power transferred from one or more of the motor phase windings and converts the AC power to DC power. A first stage power switch circuit comprising at least one power switch is connected between the at least two phase windings on the one half of the motor phase windings of the circuit and between the at least two other phase windings on the other half of the motor phase windings of the circuit. A second stage power switch circuit comprising at least one other power switch is connected between the one half of the motor phase windings of the circuit and the other half of the motor phase windings of the circuit, the at least one other power switch to receive AC power from one or more of the motor phase windings. At least one non-collapsing DC power supply component prevents the DC power supply from collapsing when the at least one power switch is on.

A circuit for a motor comprises at least two phase windings forming one half of motor phase windings of the circuit and at least two other phase windings forming another half of the motor phase windings of the circuit. A direct current (DC) power supply receives alternating current (AC) power transferred from one or more of the motor phase windings and converts the AC power to DC power. A first stage power switch circuit comprising at least one power switch is connected between the at least two phase windings on the one half of the motor phase windings of the circuit and between the at least two other phase windings on the other half of the motor phase windings of the circuit. A second stage power switch circuit comprising at least one other power switch is connected between the one half of the motor phase windings of the circuit and the other half of the motor phase windings of the circuit, the at least one other power switch to receive AC power from one or more of the motor phase windings. At least one non-collapsing DC power supply component prevents the DC power supply from collapsing when the at least one power switch is on.

A circuit for a motor comprises at least two phase windings forming one half of motor phase windings of the circuit and at least two other phase windings forming another half of the motor phase windings of the circuit. A direct current (DC) power supply receives alternating current (AC) power transferred from one or more of the motor phase windings and converts the AC power to DC power. A first stage power switch circuit comprising at least one power switch is connected between the at least two phase windings on the one half of the motor phase windings of the circuit and between the at least two other phase windings on the other half of the motor phase windings of the circuit. A second stage power switch circuit comprising at least one other power switch is connected between the one half of the motor phase windings of the circuit and the other half of the motor phase windings of the circuit, the at least one other power switch to receive AC power from one or more of the motor phase windings. At least one non-collapsing DC power supply component prevents the DC power supply from collapsing when the at least one power switch is on.

A circuit for a motor comprises at least two phase windings forming one half of motor phase windings of the circuit and at least two other phase windings forming another half of the motor phase windings of the circuit. A direct current (DC) power supply receives alternating current (AC) power transferred from one or more of the motor phase windings and converts the AC power to DC power. A first stage power switch circuit comprising at least one power switch is connected between the at least two phase windings on the one half of the motor phase windings of the circuit and between the at least two other phase windings on the other half of the motor phase windings of the circuit. A second stage power switch circuit comprising at least one other power switch is connected between the one half of the motor phase windings of the circuit and the other half of the motor phase windings of the circuit, the at least one other power switch to receive AC power from one or more of the motor phase windings. At least one non-collapsing DC power supply component prevents the DC power supply from collapsing when the at least one power switch is on.