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.

According to the present invention, provided is a motor of which a controller generates an index signal at a second time point delayed from a first time point at which a pulse due to an index magnet is detected among pulses of a pulse width modulation (PWM) signal detected by a second Hall sensor, compares a second time point which is input in advance based on a constant speed condition of the motor and a detected second time point to obtain a first error, compares a duty value, which is input in advance based on the constant speed condition of the motor, of a PWM signal and a duty value of a detected PWM signal to obtain a second error, and controls a speed of the motor on basis of the first error and the second error.

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 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.

An electric tool includes a motor, a drive circuit, a power supply and a controller. The motor includes a rotor and first, second, and third phase windings. The drive circuit is electrically connected to the first, second, and third phase windings and drives the motor to output power. The power supply is electrically connected to the drive circuit and supplies power to the first, second, and third phase windings through the drive circuit. The controller is connected to the drive circuit and outputs a control signal to control the drive circuit. The controller controls the drive circuit according to a rotation position of the rotor when a voltage of the power supply is less than or equal to a preset voltage threshold so that the first, second, and third phase windings are simultaneously connected to the power supply.

A motor driving device includes a first hysteresis comparator, a second hysteresis comparator, a logic circuit, a control unit, and an inverter circuit. The logic circuit receives a start signal or a start completion signal to output the first output signal as a commutation signal according to the start signal, or to output the second output signal as the commutation signal according to the start completion signal, clamps the second output signal by the first output signal, stops outputting the commutation signal after the potential state of the commutation signal is changed, and unclamps the second output signal with the first output signal and outputs the commutation signal in response to a difference voltage between the first input signal and the second input signal being greater than a positive value of the first hysteresis voltage or less than a negative value of the first hysteresis voltage.

In a method for generating a blocking moment in a standstill state of an electrically commutated electric motor having at least two windings, on which electric motor a possibly varying load moment acts from outside in the standstill state, first, a blocking current is supplied at a maximum value into a first winding. This blocking current is successively reduced to, possibly, a minimum value. From that moment the inductivity of the electric motor is controlled, namely by controlling the blocking current if the control deviation between the actual value and the set value of the inductivity exceeds a predetermined threshold value. Thereby, it is possible to control the blocking current in an adaptive manner insofar as, despite a varying load moment, the standstill state of the electric motor can be maintained by varying the blocking current.

A drive apparatus of an electric motor which does not include a position detection sensor, the drive apparatus includes drive portion configured to drive the electric motor on the basis of a command value inputted from outside, a number-of-rotations detection portion configured to detect a number of rotations of the electric motor driven by the drive portion, an out-of-phase judgement portion judging that the electric motor is out of phase in a case where the number of rotations detected by the number-of-rotations detection portion is less than a predetermined threshold value, and the predetermined threshold value being configured to be changed on the basis of the command value inputted from outside.

A lead angle adjustment circuit includes a counter that receives an input signal and has an output that is connected to a multiplier circuit. The multiplier circuit has an output connected to a subtractor circuit that has an output connected to a pseudo FG generator circuit. The output of the counter is also connected to a storage register that is coupled to an addition circuit through a range determination circuit, a slope determination circuit, and a multiplier determination circuit. The input signal is input to another counter which is connected to the addition circuit through a start determination circuit and an advance angle calculation circuit. The outputs of the multiplier determination circuit and the advance angle calculation circuit are input to the addition which, which generates a signal is subtracted by the subtractor circuit to generate the signal input into the pseudo FG generator circuit.

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.