A method for operating a variable capacity drive circuit of a compressor includes operating first and second four-quadrant switches in a first state in which the first four-quadrant switch is closed and the second four-quadrant switch is open such that a voltage seen by the motor is equal to an AC line voltage. The method also includes operating the first and second four-quadrant switches in a second state where the first four-quadrant switch is open and the second four-quadrant switch is closed such that the voltage seen by the motor is to zero. Further, the method includes providing a positive firing angle and a negative firing angle for defining when the first and second four-quadrant switches are operated in each of the first and second states. Moreover, the method also includes transitioning between the first and second states using the firing angles at a switching frequency determined by the AC line voltage frequency.

A load control device may control power delivered from a power source, such as an alternating-current (AC) power source, to at least two electrical loads, such as a lighting load and a motor load. The load control device may include multiple load control circuit, such as a dimmer circuit and a motor drive circuit, for controlling the power delivered to the lighting load and the motor load, respectively. The load control device may adjust the rotational speed of the motor load in a manner so as to minimize acoustic noise generated by the load control device and reduce the amount of time required to adjust the rotational speed of the motor load. The load control device may remain powered when one of the electrical loads (e.g., the lighting load) has been removed (e.g., electrically disconnected or uninstalled) and/or has failed in an open state (has “burnt out” or “blown out”).

A load control device may control power delivered from a power source, such as an alternating-current (AC) power source, to at least two electrical loads, such as a lighting load and a motor load. The load control device may include multiple load control circuit, such as a dimmer circuit and a motor drive circuit, for controlling the power delivered to the lighting load and the motor load, respectively. The load control device may adjust the rotational speed of the motor load in a manner so as to minimize acoustic noise generated by the load control device and reduce the amount of time required to adjust the rotational speed of the motor load. The load control device may remain powered when one of the electrical loads (e.g., the lighting load) has been removed (e.g., electrically disconnected or uninstalled) and/or has failed in an open state (has “burnt out” or “blown out”).

Disclosed are exemplary embodiments of systems and methods for controlling inducer motor speed. In an exemplary embodiment, a method includes changing stator voltage of an inducer motor (e.g., by changing a firing angle of a triac, using a transistor, a silicon controlled rectifier or semiconductor controlled rectifier (SCR), other switching device, etc.); determining actual inducer motor speed (e.g., by using a hall effect sensor or other speed sensor, etc.); and after determining the actual inducer motor speed, changing the motor stator voltage (e.g., by changing the firing angle of the triac, etc.) to a value at which the actual inducer motor speed is controllably regulated and/or maintained substantially at a set speed.

Examples include a method for controlling a synchronous motor using a variable speed drive. The motor includes a permanent magnet rotor generating a magnetic flux. The method includes applying a predefined electrical command signal to the motor and estimating a motor speed in response to the applying of the predefined electrical command signal. The method also includes reaching a desired estimated motor speed and, in response to reaching the desired estimated motor speed, estimating a parameter related to the magnetic flux of the permanent magnet rotor. The method further includes recording the estimated parameter.

A power conversion system converts an input alternating-current voltage having a first frequency into an output alternating-current voltage having a second frequency lower than the first frequency. The power conversion system includes a voltage converter, a PDM controller, and a feedback controller. The voltage converter converts the input alternating-current voltage into the output alternating-current voltage in accordance with control signals and outputs the output alternating-current voltage to a load. The PDM controller performs pulse density modulation of an output voltage command value of the output alternating-current voltage to generate the control signals and outputs the control signals to the voltage converter. The feedback controller generates the output voltage command value based on an output current value of the voltage converter and a state of the load and outputs the output voltage command value to the PDM controller.

Embodiments of the present disclosure relate to a refrigeration system that includes a compressor configured to circulate refrigerant along a refrigerant loop, a motor configured to drive the compressor, and a variable speed drive coupled to the motor and configured to supply power to the motor. The variable speed drive includes a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor when the motor operates below a threshold voltage, and a second secondary winding of the step down transformer, where the second secondary winding is configured to supply power at a fixed supplied voltage when the motor operates at or above the threshold voltage.

Embodiments of the present disclosure relate to a refrigeration system that includes a compressor configured to circulate refrigerant along a refrigerant loop, a motor configured to drive the compressor, and a variable speed drive coupled to the motor and configured to supply power to the motor. The variable speed drive includes a primary winding of a step down transformer coupled to an alternating current (AC) power source, a first secondary winding of the step down transformer, where the first secondary winding is configured to supply power at a variable supplied voltage to the motor when the motor operates below a threshold voltage, and a second secondary winding of the step down transformer, where the second secondary winding is configured to supply power at a fixed supplied voltage when the motor operates at or above the threshold voltage.

The present invention discloses an electric drive train comprising:—a rotor or propeller shaft (R),—an electric motor assembly (GEMD) configured to drive the rotor or propeller shaft (R), the electric motor assembly (GEMD) comprising a plurality of stacked electric motor elements (Ee1, Ee2, Ee3, Ee4),—a power branch of a first topology feeding a stacked electric motor element (Ee1) of the electric motor assembly (GEMD), said power branch (b1) comprising a RESS and an electric generator (G) supplying a power signal to said power branch (b1),—a power branch (b3) of a second topology dissimilar from the first topology, said power branch feeding another stacked electric motor element of the electric motor assembly (GEMD), said power branch (b3) comprising: # an electric generator (G) supplying a power signal to said power branch, a matrix converter (Mc3) feeding the another stacked electric motor element (Ee3), # or, an electric generator supplying Direct Current to said power branch and a motor controller feeding the second stacked electric motor element (Ee3).

An arrangement contains an asynchronous machine, which, in generator operation, is configured to feed electric power into an AC network. Accordingly, the asynchronous machine can be dual-fed by a modular multi-stage converter in a matrix configuration. The asynchronous machine has a rotor and the modular multi-stage converter is connected to the rotor of the asynchronous machine.