A method of controlling a brushless permanent magnet motor includes determining a motor operating target. The method includes comparing the motor operating target to a set of pre-determined excitation timing parameter relationships. The method includes operating the motor in accordance with an excitation timing parameter relationship determined from the set of pre-determined excitation timing parameter relationships to provide a motor operating response close to the motor operating target. The method includes measuring a measured motor operating response, comparing the measured motor operating response to the motor operating target, and applying a correction factor to an excitation timing parameter of the motor when the measured motor operating response does not match the motor operating target, such that the measured motor operating response moves toward the motor operating target.

A method of controlling a brushless permanent magnet motor includes determining a motor operating target. The method includes comparing the motor operating target to a set of pre-determined excitation timing parameter relationships. The method includes operating the motor in accordance with an excitation timing parameter relationship determined from the set of pre-determined excitation timing parameter relationships to provide a motor operating response close to the motor operating target. The method includes measuring a measured motor operating response, comparing the measured motor operating response to the motor operating target, and applying a correction factor to an excitation timing parameter of the motor when the measured motor operating response does not match the motor operating target, such that the measured motor operating response moves toward the motor operating target.

A power tool is provided including a brushless DC (BLDC) motor, a rectifier that receives an alternative current from a power supply and outputs a rectified signal supplied to a DC power bus, and an inverter circuit having motor switches connected electrically between the DC power bus and the motor. A control module controls a switching operation of the power switches to regulate supply power from the power supply to the motor. The control module controls the switching operation so as to, within a half cycle of the AC power supply voltage waveform, increase current draw from the power supply from a first threshold at or after a first zero-crossing of the half cycle up to a second threshold, and reduce current draw from the power supply from the second threshold up to a third threshold at or prior to a second zero-crossing of the half cycle.

A BLDC motor and a method for starting and operating the motor. The motor has a rotor with exciter magnets, a stator with at least three stator coils, and a control and evaluation unit. The method carries out an initialization phase with a defined start time, initial starting field angle of the stator magnetic field and angle rising rate. A partial cycle is carried out with a rising phase that increases a current field angle with a change in voltage application to the stator coils. An analysis phase keeps the current field angle constant. The method continuously records a difference in current between two phase currents of a same direction of flow, the evaluation unit analyzes the recorded difference for the presence of a current eye. Immediate commutation takes place when a current eye is detected or where without detection after a pre-definable time interval has elapsed. The analysis phase is terminated after commutation is carried out. The partial cycle is repeatedly carried out until the final field angle has increased to a value of 360° to define a total cycle.

A control method of an impact power tool includes: control a motor to rotate; continuously obtain a rotation speed signal based on a detecting result of a rotation speed detecting device and obtain a current signal based on a detecting result of a current detecting device; obtain a rotating time of each of rotation angles of the motor based on a variation of pulse waves of rotation speed signal and obtain the motor current based on the current signal; determine a number of impact that the impact mechanism produces based on a variation of the rotating time and a variation of the motor current; control the motor to stop rotating when the number of impact reaches a predetermined number. In this way, an output torque outputted by the impact power tool could be accurately controlled.

A control method of an impact power tool includes: control a motor to rotate; continuously obtain a rotation speed signal based on a detecting result of a rotation speed detecting device and obtain a current signal based on a detecting result of a current detecting device; obtain a rotating time of each of rotation angles of the motor based on a variation of pulse waves of rotation speed signal and obtain the motor current based on the current signal; determine a number of impact that the impact mechanism produces based on a variation of the rotating time and a variation of the motor current; control the motor to stop rotating when the number of impact reaches a predetermined number. In this way, an output torque outputted by the impact power tool could be accurately controlled.

A power tool comprising a housing, a motor, and a circuit board residing in the housing is provided. A rectifier that receives an alternating current and converts the alternating current to a direct current, a switching arrangement having a plurality of motor switches connected electrically between the rectifier and the motor, and a capacitor connected electrically between the rectifier and the switching arrangement, are mounted on a rear portion of a planar surface of the circuit board. A switching arrangement and at least one heat sink in thermal communication therewith are mounted on a front portion of the planar surface of the circuit board.

A power tool comprising a housing, a motor, and a circuit board residing in the housing is provided. A rectifier that receives an alternating current and converts the alternating current to a direct current, a switching arrangement having a plurality of motor switches connected electrically between the rectifier and the motor, and a capacitor connected electrically between the rectifier and the switching arrangement, are mounted on a rear portion of a planar surface of the circuit board. A switching arrangement and at least one heat sink in thermal communication therewith are mounted on a front portion of the planar surface of the circuit board.

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.