An electrical machine (1) comprises a rotor (20), a stator (10), a rotor power supply (50), at least one sensor (70) and a rotor magnetization control arrangement (60). The rotor has rotor windings (22) for controlling magnetization of rotor magnetic poles (24). The sensor is arranged to measure a parameter associated with a relative force between the stator and the rotor. The rotor magnetization control arrangement is communicationally connected to the sensor for receiving a signal representing the measured parameter. The rotor magnetic poles are divided into at least two groups (23). The rotor magnetization control arrangement is arranged for controlling the magnetization of the groups individually by providing a respective individually controllable rotor current. The rotor magnetization control arrangement is arranged to individually control the rotor currents in dependence of the signal representing the measured parameter. A method for controlling such an electrical machine is also disclosed.

An electrical machine (1) comprises a rotor (20), a stator (10), a rotor power supply (50), at least one sensor (70) and a rotor magnetization control arrangement (60). The rotor has rotor windings (22) for controlling magnetization of rotor magnetic poles (24). The sensor is arranged to measure a parameter associated with a relative force between the stator and the rotor. The rotor magnetization control arrangement is communicationally connected to the sensor for receiving a signal representing the measured parameter. The rotor magnetic poles are divided into at least two groups (23). The rotor magnetization control arrangement is arranged for controlling the magnetization of the groups individually by providing a respective individually controllable rotor current. The rotor magnetization control arrangement is arranged to individually control the rotor currents in dependence of the signal representing the measured parameter. A method for controlling such an electrical machine is also disclosed.

Disclosed herein are a motor control apparatus and method. The motor control apparatus includes a compensation signal generator configured to apply a DC-Link voltage (V.sub.Link) for driving a motor to a parameter map preset in order to estimate a gain and phase of a motor torque ripple generated when the motor is driven according to a motor command current and a motor rotation speed, and to generate a compensation signal (i.sub.comp) for compensating for the motor torque ripple corresponding to a current input motor command current (i.sub.q*), motor rotation speed (ω.sub.m), and DC-Link voltage (V.sub.Link), and a current controller configured to control the current of the motor by controlling an inverter such that a compensation command current (i.sub.q*_.sub.comp), generated by reflecting the compensation signal (i.sub.comp), in the motor command current (i.sub.q*), coincides with a motor drive current (i.sub.q) supplied to the motor from the inverter.

Disclosed herein are a motor control apparatus and method. The motor control apparatus includes a compensation signal generator configured to apply a DC-Link voltage (V.sub.Link) for driving a motor to a parameter map preset in order to estimate a gain and phase of a motor torque ripple generated when the motor is driven according to a motor command current and a motor rotation speed, and to generate a compensation signal (i.sub.comp) for compensating for the motor torque ripple corresponding to a current input motor command current (i.sub.q*), motor rotation speed (ω.sub.m), and DC-Link voltage (V.sub.Link), and a current controller configured to control the current of the motor by controlling an inverter such that a compensation command current (i.sub.q*_.sub.comp), generated by reflecting the compensation signal (i.sub.comp), in the motor command current (i.sub.q*), coincides with a motor drive current (i.sub.q) supplied to the motor from the inverter.

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 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 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 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.

The invention relates to an energy efficient induction motor (100) comprising a stator (102), a main winding (M) of the stator (102) for generating a rotating magnetic field (RMF) (108), and a rotor (104) disposed to rotate relative to the main winding (M) of the stator (102) due to the RMF (108). The stator (102) comprises additional winding(s) (A) for producing an alternating EMF (110) which is induced in the one or more additional windings (A) due to the rotation of the rotor (104). The alternating EMF (110) produced in the one or more additional windings (A) is fed back simultaneously to the main winding (M) of the stator (102) throughout the complete rotation cycle of the rotor (104) through an electronic control unit (112) coupled to the stator (102), producing a resultant AC output power (116) that is fed continuously to the main winding (M) of the stator (102).

The invention relates to an energy efficient induction motor (100) comprising a stator (102), a main winding (M) of the stator (102) for generating a rotating magnetic field (RMF) (108), and a rotor (104) disposed to rotate relative to the main winding (M) of the stator (102) due to the RMF (108). The stator (102) comprises additional winding(s) (A) for producing an alternating EMF (110) which is induced in the one or more additional windings (A) due to the rotation of the rotor (104). The alternating EMF (110) produced in the one or more additional windings (A) is fed back simultaneously to the main winding (M) of the stator (102) throughout the complete rotation cycle of the rotor (104) through an electronic control unit (112) coupled to the stator (102), producing a resultant AC output power (116) that is fed continuously to the main winding (M) of the stator (102).