The present relates to a sensorless driving apparatus and a sensorless driving method for a brushless motor. In a state that the brushless motor is driven by rectangular waves, when the driving apparatus detects that a rotation speed of the brushless motor becomes higher than a predetermined speed and thereafter it detects that an angle of a rotor of the brushless motor becomes a predetermined angle, the driving apparatus switches the drive from rectangular wave drive to sign wave drive. The driving apparatus sets as the predetermined angle an angle at which energizing mode is switched in the rectangular wave drive or an angle at which a motor torque is at a peak value in the rectangular wave drive.

A cleaner includes a BLDC motor and a power unit. The BLDC motor includes a rotor and a stator provided with a DC coil and an AC coil in a separate manner. The power unit is configured to supply DC power and AC power to the DC coil and the AC coil, respectively.

A method for determining a movement of a rotor of an electric motor, comprises supplying a drive signal to a drive coil of the electric motor, sensing a coil current of the drive coil, detecting current ripples of the sensed coil current caused by the rotor of the electric motor crossing ripple generating positions, inferring the movement of the rotor from the detected ripples, braking the motor by reducing the drive signal supplied to the drive coil from an initial signal value to zero according to a braking curve specifying a non-zero fall time during which the drive signal is reduced from the initial signal value to zero. The braking curve is adapted so that the rotor does not cross a ripple generating position after the drive signal has been reduced to zero.

Two inverters provided at respective both ends of open-end windings are appropriately controlled. A rotating electrical machine control device (1) that can control a first inverter (11) and a second inverter (12) by a plurality of control schemes, respectively, the control schemes differing from each other in at least one of a switching pattern and a switching frequency and being independent of each other, has a control mode in which the first inverter (11) and the second inverter (12) are controlled by the same control scheme in a first speed region (VR1) in which the rotational speed of a rotating electrical machine (80), and the first inverter (11) and the second inverter (12) are controlled by different control schemes in a second speed region (VR2) in which the rotational speed of the rotating electrical machine (80) is higher than in the first speed region (VR1).

A motor control device includes an electric power converter for generating three-phase voltages based on voltage instruction-values, and for supplying them to a motor; an induced-voltage estimation unit for estimating an induced voltage of the motor, based on the voltage instruction-values and electric current feedback values; a dead-time disturbance-voltage compensation unit; and a dead-time disturbance compensation-voltage modification unit for compensating a dead-time disturbance voltage(s) generated in the electric power converter, based on a fundamental wave component of an estimated induced voltage.

A motor controller configured to be coupled to a motor and to a system controller is described. The motor controller includes a proportional-integral (PI) regulator coupled to a timer controller. The motor controller is configured to generate, by the PI regulator, a pulsed signal representing a reported speed of the motor. Additionally, the motor controller is configured to transmit the pulsed signal to the system controller, measure a time period that elapses for the motor to make a predefined number of revolutions, measure a number of pulses transmitted in the pulsed signal, and determine a measured speed of the motor from the time period. Further, the motor controller is configured to determine, by the PI regulator, a difference between the reported speed and the measured speed, and adjust, by the PI regulator, the pulsed signal based on the difference between the reported speed and the measured speed.

The invention relates to an input stage (1) for a motor controller (2), especially a motor controller for an electric motor, the input stage (1) being provided with an input (3) for inputting an input signal and an output (4) for connection to the motor controller (2). The input stage (1) is designed to generate a control signal from an input signal between a first voltage U.sub.unten and a second voltage U.sub.oben and output said control signal as a parameter to the motor controller (2) via the output (4). In order to be able to simultaneously use the control input (13) for communicating, the input stage (1) comprises a first comparator (5) for comparing the input signal with a first threshold voltage U.sub.s1>U.sub.oben as well as a data output unit (10). The data output unit (10) generates a communication signal on the basis of at least one portion of the input signal. When the input signal reaches or exceeds the first threshold voltage U.sub.s1, the first comparator (5) outputs an activation signal which activates output of the communication signal to the output (4) by the data output unit (10). The invention further relates to a motor controller, especially for an electric motor, comprising a corresponding input stage, and to an interface adapter for the input stage.

A resistance calculation activator determines whether or not an electric car is stopped on the basis of a drive command signal and an external signal, and activates a resistance calculator if a powering command is input as the drive command when it is determined that the electric car is stopped. The activated resistance calculator computes, within a resistance calculation period, a resistance value of an AC motor that produces driving force for the electric car, on the basis of a d-axis voltage command value and a d-axis current value supplied to the AC motor.

An embodiment of a linear electric machine includes two or more phases that define a central bore, and alternating permanent magnets that are disposed within the central bore and are free to move relative the windings. An embodiment of a method for selectively powering the windings is disclosed that enables the machine to realize a commanded force, or to determine the force present by using the current within the windings and the alignment of the magnets relative to the windings.

An embodiment of a linear electric machine includes two or more phases that define a central bore, and alternating permanent magnets that are disposed within the central bore and are free to move relative the windings. An embodiment of a method for selectively powering the windings is disclosed that enables the machine to realize a commanded force, or to determine the force present by using the current within the windings and the alignment of the magnets relative to the windings.