A system to reconfigure a motor from induction mode to synchronous mode at a zero crossing of the field voltage during startup using only stator current signals is described herein. The zero crossing may be detected by asymmetry induced in the stator currents by a current asymmetry inducing module of the motor. The current asymmetry inducing module may include a resistor and diode in series and in parallel with a discharge resistor of the field windings. Asymmetry is induced in the current obtained from the stator, and used to determine a zero crossing of the field voltage. Upon the rotor reaching a startup frequency and the detected zero-crossing of the field voltage, the motor may be reconfigured from induction mode to synchronous mode.

A system to reconfigure a motor from induction mode to synchronous mode at a zero crossing of the field voltage during startup using only stator current signals is described herein. The zero crossing may be detected by asymmetry induced in the stator currents by a current asymmetry inducing module of the motor. The current asymmetry inducing module may include a resistor and diode in series and in parallel with a discharge resistor of the field windings. Asymmetry is induced in the current obtained from the stator, and used to determine a zero crossing of the field voltage. Upon the rotor reaching a startup frequency and the detected zero-crossing of the field voltage, the motor may be reconfigured from induction mode to synchronous mode.

A rotation detector includes a motor, a current detector and a hardware processor. The motor includes coils of two or more phases and a rotor. The current detector detects currents flowing in coils of at least two phases among the coils of two or more phases. The hardware processor estimates an initial position of the rotor based on current values of the currents detected by the current detector to start the motor, controls an energization pattern on the phases to rotate and start the motor based on the estimated initial position, and determines whether the rotor stops or is rotating before completing the estimation of the initial position.

Described is a vector control system for a vapor compression circuit. The vector control system may monitor the vapor compression circuit and adjust the speed of one or more motors to increase efficiency by taking into account the torque forces placed on a compressor motor.

Apparatus and methods for controlling electric motors are disclosed. In addition, such apparatus and methods for starting and controlling electric motors and controlling electric motors switching from a PWM control to six step method of control. Methods and apparatus are further included to provide for robust control of an electric motor operating in a six-step running mode.

Apparatus and methods for controlling electric motors are disclosed. In addition, such apparatus and methods for starting and controlling electric motors and controlling electric motors switching from a PWM control to six step method of control. Methods and apparatus are further included to provide for robust control of an electric motor operating in a six-step running mode.

A motor control apparatus includes: a current supply unit configured to supply a coil current to a plurality of coils of a motor by controlling a voltage to be applied to the plurality of coils, based on a first command value of an excitation current and a second command value of a torque current; and a control unit configured to control the first command value based on a rotation speed of a rotor of the motor, wherein the control unit is further configured to control, when the rotation speed of the rotor is lower than a first threshold value, the first command value to cause the excitation current to be larger than zero, and control the second command value to supply the torque current in accordance with a load of the rotor.

A compressor and a control method thereof are provided. The compressor includes a motor with a rotor of a permanent magnet. According to embodiments, the method of controlling the compressor includes: applying a detection current to the motor in response to a command of starting the compressor; detecting whether there is demagnetization of the permanent magnet of the rotor according to a response of the motor to the applied detection current; resetting an operating parameter of the compressor if there is the demagnetization; and starting the compressor according to the reset operating parameters. According to embodiments of the present disclosure, when the compressor is to be started, demagnetization is detected first, and the operating parameter are set accordingly, so as to suppress or avoid performance degeneration due to the demagnetization.

A compressor and a control method thereof are provided. The compressor includes a motor with a rotor of a permanent magnet. According to embodiments, the method of controlling the compressor includes: applying a detection current to the motor in response to a command of starting the compressor; detecting whether there is demagnetization of the permanent magnet of the rotor according to a response of the motor to the applied detection current; resetting an operating parameter of the compressor if there is the demagnetization; and starting the compressor according to the reset operating parameters. According to embodiments of the present disclosure, when the compressor is to be started, demagnetization is detected first, and the operating parameter are set accordingly, so as to suppress or avoid performance degeneration due to the demagnetization.

The disclosure relates to an autonomous apparatus, moving and performing preset work in a defined working area, the autonomous apparatus including an energy module supplying energy to the autonomous apparatus, a motor, a sensor circuit, and a control circuit, the motor obtaining the energy from the energy module, to drive the autonomous apparatus to move and/or work in the working area, the sensor circuit detecting working parameters and environmental parameters of the autonomous apparatus, and transmitting detection results to the control circuit, the control circuit controlling the operation of the motor according to a signal transmitted by the sensor circuit, where the motor is a sensorless brushless motor, and before the motor rotates, the control circuit measures a resistance value of the motor, and estimates, one the basis of the resistance value of the motor, a rotor position of the motor, so as to control the operation of the motor.