A power system may include a first motor, a second motor connected in parallel to the first motor, a driver configured to supply a driving current to the first motor and the second motor and a controller configured to control the driver based on the driving current and a rotating speed of the first motor, and when the rotating speed of the first motor is different from a rotating speed of the second motor, the controller may control the driver so that the rotating speed of the first motor is equal to the rotating speed of the second motor. The power system may drive two and more motors at the same speed by applying the driving voltage based on the rotating speed and the driving current of one of two or more motors, using a single driving apparatus.

A power system may include a first motor, a second motor connected in parallel to the first motor, a driver configured to supply a driving current to the first motor and the second motor and a controller configured to control the driver based on the driving current and a rotating speed of the first motor, and when the rotating speed of the first motor is different from a rotating speed of the second motor, the controller may control the driver so that the rotating speed of the first motor is equal to the rotating speed of the second motor. The power system may drive two and more motors at the same speed by applying the driving voltage based on the rotating speed and the driving current of one of two or more motors, using a single driving apparatus.

A fan assembly comprising a plurality of nested components comprising a first stator; a first rotor that is radially spaced from the first stator, wherein the first rotor is magnetically driven by the first stator, the first rotor includes a second stator whereby the second stator rotates with the first rotor; a second rotor that is radially spaced from the second stator, wherein the second rotor is magnetically driven by the second stator; and, a fan blade drivenly connected to the second rotor.

A fan assembly comprising a plurality of nested components comprising a first stator; a first rotor that is radially spaced from the first stator, wherein the first rotor is magnetically driven by the first stator, the first rotor includes a second stator whereby the second stator rotates with the first rotor; a second rotor that is radially spaced from the second stator, wherein the second rotor is magnetically driven by the second stator; and, a fan blade drivenly connected to the second rotor.

An eccentric mass vibrating system comprising: a first motor having a first shaft; a first eccentric mass connected to said first shaft; a second motor having a second shaft; a second eccentric mass connected to said second shaft; said first motor and said second motor are adapted to be associated with an object to be vibrated; said first motor and said second motor being electrically adjustable so as to arrange said first eccentric mass and said second eccentric mass at a predefined angle therebetween; said first motor and said second motor being adapted to be positioned on an object to be vibrated; characterised in that it comprises: at least one sensor associated with said object to be vibrated, and a control computer of said system adapted to modify said predefined angle if the value measured by said sensor exceeds a predefined value.

An eccentric mass vibrating system comprising: a first motor having a first shaft; a first eccentric mass connected to said first shaft; a second motor having a second shaft; a second eccentric mass connected to said second shaft; said first motor and said second motor are adapted to be associated with an object to be vibrated; said first motor and said second motor being electrically adjustable so as to arrange said first eccentric mass and said second eccentric mass at a predefined angle therebetween; said first motor and said second motor being adapted to be positioned on an object to be vibrated; characterised in that it comprises: at least one sensor associated with said object to be vibrated, and a control computer of said system adapted to modify said predefined angle if the value measured by said sensor exceeds a predefined value.

A control method for a semi-centralized open winding multi-motor drive system includes: first, measuring current, voltage and position signal, computing system thrust by a velocity loop; then, distributing the thrust to each motor, converting the thrust into q axis current, computing dq axis voltages required for each motor by a current loop, and transforming the voltage demand to abc coordinate system through coordinate transformation; subsequently, modulating the voltage of each motor into a duty ratio instruction to judge whether the motor is in an over-modulated operating area, and performing over-modulation processing on the voltage in the over-modulated area; and finally, distributing the duty ratio instructions to independent and shared inverters. The control method of the present disclosure can reduce the hardware cost and improve the safety and reliability of the system.

A control method for a semi-centralized open winding multi-motor drive system includes: first, measuring current, voltage and position signal, computing system thrust by a velocity loop; then, distributing the thrust to each motor, converting the thrust into q axis current, computing dq axis voltages required for each motor by a current loop, and transforming the voltage demand to abc coordinate system through coordinate transformation; subsequently, modulating the voltage of each motor into a duty ratio instruction to judge whether the motor is in an over-modulated operating area, and performing over-modulation processing on the voltage in the over-modulated area; and finally, distributing the duty ratio instructions to independent and shared inverters. The control method of the present disclosure can reduce the hardware cost and improve the safety and reliability of the system.

A motor which may be used within an appliance. The motor may include a fixed stator with a plurality of stator poles provided by electromagnets (e.g. wound coils) and at least one rotor. The activation of the rotor poles (e.g. the number of active rotor poles and/or the rotor pole switching frequency) can be controlled independent of the activation of the stator poles (e.g. the number of active stator poles and/or stator pole switching frequency). The motor may include multiple rotors connected in sequence to allow for increased fan speeds with relatively decreased dB level as well as a decrease in the size of the fan assembly.

A dual motor actuator according to an embodiment includes a main motor actuator outputting torque to a main output shaft by including a main motor and a main reduction gear, an auxiliary motor actuator outputting torque to an auxiliary output shaft by including an auxiliary motor and an auxiliary reduction gear, and a clutch connecting the main output shaft and the auxiliary output shaft to each other, wherein the clutch includes a fixed clutch connected to the main output shaft and a movable clutch coupled to or released from the fixed clutch and connected to the auxiliary output shaft, and the dual motor actuator further includes an output unit connected to the movable clutch and transmitting an output from the main motor actuator or the auxiliary motor actuator.