An error detector generates a position error value ERR that corresponds to a difference between a position instruction value P_REF indicative of a target position of a rotor based on a clock signal CLK and a position detection value P_FB indicative of the current position of the rotor based on pulse signals EN_A and EN_B received from an encoder. A feedback controller generates a torque instruction value T_REF such that a position error value ERR approaches zero. The driving IC is capable of switching modes between a rotational driving control mode and a holding mode. Control characteristics set for the feedback controller are switched according to switching between the rotational driving control mode and the holding mode.

In a motor control device, a rotational phase detection unit detects a rotational phase of a rotor of a stepping motor, and a driving waveform generation unit generates a driving waveform for driving the stepping motor. An advance angle control unit detects a phase difference (advance angle) between a rotational phase of the rotor and a phase of the driving waveform and controls an amplitude or a period of the driving waveform generated by the driving waveform generation unit to perform advance angle control. The advance angle control unit controls an amplitude of the driving waveform by determining a target advance angle based on a variation (advance angle change rate) of an advance angle with respect to a variation of an amplitude in accordance with a change in the advance angle when the amplitude of the driving waveform is changed.

An apparatus includes at least one processor or circuit programmed to function as a detection unit that detects a rotational position of a rotor, and a generation unit that generates a driving waveform for a motor based on the detected rotational position. The generation unit includes a phase difference setting unit that sets a phase difference between the rotational position and the driving waveform, a changing time setting unit that sets a changing time, which is a time required for changing the phase difference from a phase difference before the change to a phase difference after the change, in a case where the set phase difference is changed, and a determination unit that determines a phase of the driving waveform based on the phase difference before the change, the phase difference after the change, and the changing time.

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.

A stepping motor includes a slit rotating plate that rotates together with a rotor and two photo interrupters. A motor control device includes a rotation phase detection unit that acquires an output of the photo interrupter and detects a rotation phase of the rotor, and a drive waveform generation unit that generates a drive waveform of the stepping motor. An advance angle control unit performs speed control of the stepping motor by detecting an advance angle corresponding to a phase difference between the rotation phase of the rotor and the drive waveform and setting an advance angle at which a relationship between an amplitude and an advance angle of the drive waveform changes abruptly as a target advance angle to control an amplitude of the drive waveform.

The present invention addresses the problem of providing a method for detecting magnetic field location which can realize low cost by using simple hardware and software and can detect a rotor location in units of excitation sections in 120-energization without generating sensing noise at the time of initiation. As a solution, an MPU (51) obtains, through calculation, a neutral point potential from an energization-phase voltage measured by an A/D conversion circuit (53), obtains the difference between the neutral point potential and a non-energization-phase voltage, performs magnitude comparison between the difference and a negative-side threshold value in the case where the present location is an odd-numbered section or between the difference and a positive-side threshold value in the case where the present location is an even-numbered section, and determines the end point of the 60-energization section when the difference exceeds a threshold value in a direction away from the neutral point potential.

A method of controlling the commutation of a brushless direct current motor includes providing sensors which provide a variable output dependent on rotational angle or the relative position of the stator and rotor of the motor. Output from the sensors is sampled at a time between a past commutation event and the next commutation event to be implemented. An angular position between the rotor and stator is determined at the time. The time of the next commutation event is determined based on the next commutation angle, motor speed, and the determined angular position.

An electric working machine includes an inverter and a controller. The controller switches a current conduction pattern via the inverter and performs a PWM control of a conduction current to a brushless motor. The controller includes switching patterns as the current conduction pattern switched for every commutation timing. The switching patterns include different on and off states for different switching elements. The controller sequentially switches a switching pattern synchronously with a period of the PWM control, detects a rotational position of a brushless motor from a magnitude relation between inductances of the brushless motor produced by switching the switching pattern, and sets the commutation timing.

A wiper device is provided. A boost control unit, if a duty ratio has reached an upper limit value determined in advance, and if the rotational speed of a motor is less than a target rotational speed, varies an advance angle and an energization angle associated with the energization of the motor in accordance with the target rotational speed. An overtemperature protection unit monitors a load state of the motor, and, upon detecting a high-load state, performs a first protection control for decreasing the rotational speed of the motor. A demagnetization protection unit, upon receipt of an operating signal from a wiper switch when the temperature detected by means of a temperature sensor exceeds a first threshold and the first protection control is being performed, performs a second protection control for fixing the advance angle and energization angle of the motor by prohibiting the operation of the boost control unit.

Systems and methods for computing an average supply current to a motor include a current sensor that is configured to sense a current through the motor. A converter is configured to sample the output of the current sensor at times that are established by a trigger signal and convert the samples into digital current values. A trigger signal generator generates the trigger signal based on one or more pulse width modulated (PWM) motor control signals within a PWM cycle. An average supply current value that indicates the average supply current to the motor is computed by a controller using the digital current values received from the converter.