Methods and systems for controlling an electric motor using a motor controller including a processor are provided. The method includes transmitting, by the processor, a no-spin signal commanding the electric motor not to spin, receiving temperature information associated with a temperature of the electric motor, comparing the temperature information to a predetermined threshold temperature to determine whether the temperature is at a sufficient level to prevent icing, and adjusting current applied to the electric motor when the temperature measurement is below the predetermined threshold.

Methods and systems for controlling an electric motor using a motor controller including a processor are provided. The method includes transmitting, by the processor, a no-spin signal commanding the electric motor not to spin, receiving temperature information associated with a temperature of the electric motor, comparing the temperature information to a predetermined threshold temperature to determine whether the temperature is at a sufficient level to prevent icing, and adjusting current applied to the electric motor when the temperature measurement is below the predetermined threshold.

A motor, a driving circuit thereof and a driving method thereof are provided. The motor driving method includes: during a motor starting stage, when a detected rotor magnetic field is a first polarity and a polarity of an AC power source is positive, or the detected rotor magnetic field is a second polarity and the polarity of the AC power source is negative after a zero voltage crossing point of the AC power source, instantly sending a trigger pulse to a controllable bidirectional AC switch connected in series with a motor winding at both ends of the AC power source; during a motor operating stage, after the zero voltage crossing point of the AC power source, sending a trigger pulse to the controllable bidirectional AC switch after a delay time after the zero voltage crossing point. This method can provide a large torque during the motor starting stage.

Provided is a method for determining the rotational position of a rotor in a permanent magnet synchronous machine, wherein the stator includes windings for a first, second and third phase, including the steps: applying a first voltage pulse to the first phase, determining respective first measures for the current induced by the first voltage pulse in the second and third phase, selecting a first selected phase depending on the first measures for the current, wherein the first selected phase is either the second or the third phase, applying a second voltage pulse to the first selected phase, determining respective second measures for the current induced by the second voltage pulse in the phases of the stator that are not the first selected phase, and determining the rotational position of the rotor depending on the second measures of the current.

Utilizing an asymmetric magnetic field caused by a mechanism design between a motor rotor and a stator to induce a BEMF, a method for starting a fixed rotation direction of single-phase sensorless DC brushless motor, includes: power-on starting a motor control circuit; if the motor is not in a rotating state before starting the excitation, executing a static starting procedure; then, if the motor rotation direction conforms to a predetermined direction, executing a normal driving procedure; otherwise, executing a static starting procedure. The static starting procedure, by discharging remnant energy of the motor, achieves the purpose of star-up by performing the steps of first phase excitation, stop excitation, and strong second phase excitation. In the normal driving procedure, the slope of BEMF signal of the first phase or the second phase is taken out periodically to detect the motor rotation direction.

A driving device includes a connection switching unit to switch a connection state of coils between a first connection state and a second connection state in which a line voltage is lower than in the first connection state, a controller to control a motor and the connection switching unit, and a rotation speed detector to detect a rotation speed of the motor. When the connection state of the coils is the first connection state and the rotation speed detected by the rotation speed detector becomes higher than or equal to a first rotation speed, the controller causes the motor to rotate at a second rotation speed higher than the first rotation speed, and then causes the connection switching unit to switch the connection state of the coils from the first connection state to the second connection state.

A system may include a prime mover configured to provide mechanical energy to the system by spinning a shaft. The system further includes a synchronous AC generator mechanically coupled to the shaft, and an exciter mechanically coupled to the shaft and configured to output a field current for exciting the synchronous AC generator. The system also includes a number of synchronous electric motors electrically coupled to the AC generator and configured to drive one or more mechanical loads. A controller of the system is configured to establish and maintain a magnetic coupling between the synchronous AC generator and the synchronous electric motors by controlling a level of the field current during a ramped increase in rotation of the synchronous AC generator from zero rotational speed. The motors accelerate synchronously with the generator due to the magnetic coupling as the rotational speed of the generator increases.

A thyristor starter accelerates a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. A second controller controls the firing phase of a thyristor in a converter such that DC output current of the converter matches a current command value, based on a detection signal of a position detector. In the first mode, the current command value is set such that the current value is higher as the rotation speed of the synchronous machine is higher.

A thyristor starter accelerates a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. A second controller controls the firing phase of a thyristor in a converter such that DC output current of the converter matches a current command value, based on a detection signal of a position detector. In the first mode, the current command value is set such that the current value is higher as the rotation speed of the synchronous machine is higher.

A washing machine including a rotating tub and a motor applying a driving force to the rotating tub. The washing machine configured to generate a starting current to be applied to the motor when it is a start time of the motor, accelerate the speed of the motor stepwise while the starting current is applied to the motor, check a current of a torque component when it is determined as a deceleration time or a stop time, and apply a current of a magnetic flux component greater than the magnitude of the current of the checked torque component to the motor.