Disclosed are a control apparatus for dynamically adjusting a phase switching of a DC motor and a method thereof. A rotor in the DC motor is divided into 2 M pole areas, wherein M is a positive integer not less than 1. The control apparatus comprises a phase detector, a current detector, a control circuit and a driving circuit. The phase detector detects the phase switching state of the pole areas to generate a standard phase signal. The current detector detects a current flowing through the DC motor in one of switching points of the standard phase signal to generate a current detection value. The control circuit periodically outputs 2 M drive signals, and determines to perform dynamically adjusting operation on the timing sequence of the drive signals according to the current detection value. The driving circuit receives the drive signals to perform the phase switching for driving the DC motor.

In a method for controlling an operation of an electric motor, electric voltages applied to electric phases of the electric motor are generated and output in a modulation in a controlled manner dependent on a rotor position of the electric motor and a target/actual comparison of at least one first variable which characterizes a load on the electric motor or an actual rotational speed of the electric motor. A rotor position angle, which characterizes the rotor position, is complemented with a specified preliminary control angle and another regulated preliminary control angle component upon reaching a field weakening range of the electric motor so as to form a sum angle. The sum angle is used to characterize the rotor position in the modulation upon reaching the field weakening range. The disclosure also relates to a device for controlling an operation of an electric motor.

Provided is an electric tool capable of continuing work by making the electrical advance angle of a brushless motor changeable even when a load is heavy. The electric tool is provided with: a brushless motor; a controller for controlling the drive of the brushless motor; and an inverter circuit supplied with a pulsation voltage obtained by rectifying an AC power supply input in a full-wave manner and electrifying the brushless motor 1 according to a control signal of the controller. The controller can change the electrical advance angle of the brushless motor. The controller detects the motor current flowing through the brushless motor and increases the electrical advance angle when the motor current reaches a predetermined threshold value.

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.

A motor control device for controlling a brushless motor including a rotor and a three-phase armature coil includes: a position detection unit which detects the rotational position of the rotor; a control unit which outputs, in a first control mode or a second control mode, a first drive signal or a second drive signal to an inverter at a current-supply timing based on the rotational position of the rotor; and the inverter which outputs a first current-supply signal or a second current-supply signal to the three-phase armature coil when the first drive signal or the second drive signal is input. For any two of the three phases, a duty value when the duty of the applied voltages is the same is larger in the second control mode than in the first control mode.

The present disclosure provides a motor driving device. The motor driving device includes: a control signal generator, identifying a rotor position according to a position detection signal of the rotor of a three-phase motor, and outputting a digital control signal corresponding to the position identified; a DA converter, generating first and second command phase voltages corresponding to two of U, V and W phases by a resistance ladder according to the control signal; a periodic voltage generator, generating a periodic voltage; first and second comparators, generating first and second pulse width modulation (PWM) signals by comparing the first and second command phase voltages and the periodic voltage; and a logic circuit, implementing a two-phase modulation by assigning the first and second PWM signals to any two of the U, V and W phases according to the position detection signal.

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.

A driving circuit for a motor has a multiplexer, a current polarity detection circuit, a first comparison circuit, a reverse current control circuit, a first bridge circuit, and a second bridge circuit. The multiplexer chooses a voltage at a common node of two switches of the first bridge circuit or a voltage at a common node of two switches of the second bridge circuit as a chosen common node voltage based on a hall sensing signal. The comparison circuit provides a comparison signal by comparing the chosen common node voltage with an input voltage. The reverse current control circuit determines whether to control a low-side switch of the first bridge circuit or a low-side switch of the second bridge circuit to work in a low-dropout linear regulation (LDO) mode based on the comparison signal and a polarity indication signal provided by the current polarity detection circuit.

A brushless motor includes: a stator having a three-phase winding; a rotor that has a permanent magnet; an inverter that supplies an AC current to the three-phase wiring by turning on or turning off a plurality of switching elements; and a control part that controls an ON or OFF state of the plurality of switching elements by switching a power distribution pattern that represents a change of a power distribution state of each phase of the three-phase wiring in response to a rotation of the rotor to a low-speed power distribution pattern in use for a low-speed power distribution control or a high-speed power distribution pattern in use for a high-speed power distribution control, wherein the control part switches the power distribution pattern to the low-speed power distribution pattern in a case where a rotation speed of the rotor is less than a predetermined threshold value, and the control part switches the power distribution pattern to the high-speed power distribution pattern when a state in which a load of the rotor is within a predetermined range is continued for a predetermined period of time in a case where the rotation speed of the rotor is equal to or more than the threshold value.

A motor drive device includes a single-phase inverter that converts a direct-current voltage output from a power supply which is a battery, into an alternating-current voltage. The inverter outputs the alternating-current voltage as an applied voltage to be applied to a motor. The applied voltage is lower when the direct-current voltage is a second voltage lower than a first voltage than when the direct-current voltage is the first voltage. Consequently, a discharge current of the battery is reduced, and the motor drive device capable of reducing an increase in battery temperature can be obtained.