A motor control apparatus includes: an excitation unit configured to excite a plurality of excitation phases of each of a plurality of motors that include first to Nth motors and a control unit configured to control the excitation unit so as to perform detection excitation processing for sequentially exciting the plurality of excitation phases for each excitation cycle during each excitation period, regarding each of the first to Nth motors, and thereby detect rotor positions of the respective first to Nth motors. When detecting rotor positions of the respective first to Nth motors, the control unit delays a start timing of the detection excitation processing of at least one motor out of the first to Nth motors relative to a start timing of the detection excitation processing of another motor by a period shorter than the excitation period.

An arithmetic circuit includes an auto-zero amplification circuit that compensates an offset of an entered differential signal, and a comparator circuit that converts an output signal from the auto-zero amplification circuit to a digital signal. The auto-zero amplification circuit and comparator circuit are provided in the same package.

A shift range switching control device for switching a shift range by controlling driving of a motor includes a feedback control section, a stationary phase energization control section, and a switching control section. The feedback control section performs a feedback control based on an actual angle of the motor, and a motor speed. The stationary phase energization control section performs a stationary phase energization control which energizes a stationary phase selected according to the actual angle. The switching control section switches the control state of the motor.

A motor control apparatus includes: an excitation unit configured to excite a plurality of excitation phases of each of a plurality of motors that include first to Nth motors and a control unit configured to control the excitation unit so as to perform detection excitation processing for sequentially exciting the plurality of excitation phases for each excitation cycle during each excitation period, regarding each of the first to Nth motors, and thereby detect rotor positions of the respective first to Nth motors. When detecting rotor positions of the respective first to Nth motors, the control unit delays a start timing of the detection excitation processing of at least one motor out of the first to Nth motors relative to a start timing of the detection excitation processing of another motor by a period shorter than the excitation period.

The invention relates to a method for operating an electronically commutated electric motor (10), in which method, during ongoing operation of the electric motor (10), in order to achieve an optimal operating point of the electric motor (10), a pre-commutation angle (14) provided by a control device (12) is regulated. According to the invention, during an operation of the electric motor (10), a period signal (16) is modulated to the pre-commutation angle (14) and a state parameter (18) of the electric motor (10) correlating with an efficiency of the electric motor (10) is detected.

An interpolation circuit comprising: a phase shift circuit, configured to generate a plurality of phase shift signals; a first multiplexer configured to receive at least portion of the phase shift signals; a first comparator, comprising a first positive input terminal and a first negative input terminal; a second comparator, comprising a second positive input terminal and a second negative input terminal; a first state control circuit, configured to control the first multiplexer to switch to a different state according to a first comparing result and a second comparing result, wherein the first multiplexer outputs different ones of the phase shift signals in different states; and a first voltage level compensating circuit, configured to pull up or pull down a first output signal from the first output terminal or a second output signal from the second output terminal when the state of the first multiplexer changes.

A control device (1) is configured to reduce the commutation angle error ε of a three-phase (u, v, w) EC motor (2.2) connected via a y-configuration. The three phases (u, v, w) are commutated via a motor control (3) including a rotor position sensor (4) and a control circuit (10). The rotor position sensor (4) senses the relative angular position of the rotor using the neutral-point potential at the neutral point of the y-configuration. The control circuit (10) is configured to impose a desired field weakening current component on the motor control (3) for reducing the commutation angle error ε.

A motor controller comprises a switch circuit and a control unit. The switch circuit is coupled to a motor for driving the motor. The control unit generates a control signal to control the switch circuit. The motor controller determines a non-excitation time. When the motor is in a locked state, the motor controller enables the non-excitation time to be a variable value. The motor controller utilizes the non-excitation time to achieve a lock protection function. The motor controller determines whether the motor is in the locked state by detecting a rotor speed or a rotor temperature. Moreover, the motor controller further comprises a driving signal, where the driving signal has the non-excitation time.

A motor drive device enabling efficient position control at a low cost is provided. The motor drive device includes a position detection unit configured to detect a current position of an object to be driven by a motor and a motor control unit configured to calculate an output control amount for the motor based on a deviation between the current position and a target position of the object to be driven by the motor while changing an advance angle in a rotational phase of the motor according to the output control amount when the advance angle is within a predetermined advance angle range in the rotational phase of the motor and changing a drive voltage of the motor with the advance angle fixed when the advance angle is outside the predetermined advance angle range.

A power tool includes a brushless motor including several windings, a drive circuit for driving the brushless motor, a detection device for detecting the brushless motor so as to obtain a load parameter corresponding to a load of the brushless motor, and a controller for outputting a first control signal to reduce current of the brushless motor in a first slope when the load parameter exceeds a first preset range.