A method for configuring a variable speed drive in charge of power supply of an electric motor. The method comprises the application of a sequence of motor voltages to the electric motor by the variable speed drive and the obtaining, in parallel, of measurements of motor current. The method then determines a feature of the electric motor on the basis of the measurements of motor current and determines a type of electric motor at least as a function of the feature. The variable speed drive is then set up on the basis of the determined type of electric motor.

A power tool has a functional component, a motor, a power supply module, a controller and a drive circuit including a first drive terminal and a second drive terminal respectively electrically connected to a first power terminal and a second power terminal of the power supply module, multiple high-side switches wherein high-side terminals of the high-side switches are respectively electrically connected to the first drive terminal, and multiple low-side switches wherein low-side terminals of the low-side switches are respectively electrically connected to the second drive terminal. The controller is configured to output a first control signal to one high-side switch to place it in an on or off state and output a second control signal to one low-side switch to place it in the other state. The low-side terminal of one high-side switch is connected to the high-side terminal of one low-side switch.

A gate driving circuit applied to motor inverter includes first power switch circuit, first and second bootstrap fast charging circuits, and first, second and third capacitors. The first power switch circuit includes first and second power switches. The first bootstrap fast charging circuit is electrically connected to the first power switch. The second bootstrap fast charging circuit is electrically connected to the second power switch. The first capacitor is electrically connected to the first power switch. The second capacitor is electrically connected to the first bootstrap fast charging circuit and first insulated switch. The third capacitor is electrically connected to the second bootstrap fast charging circuit and second insulated switch. When the first power switch is disabled and the second power switch is enabled, an independent power supply enables the second bootstrap fast charging circuit to charge the third capacitor to enable the second insulated switch.

Methods and power tools for sensorless motor control. One embodiment provides a method for automatic control switching for driving a sensorless motor (150) of a power tool (100). The method includes determining, using a motor controller (224), a first load point based on user inputs (232) and determining, using the motor controller (224), a first motor control technique corresponding to the first load point. The method also includes driving the motor (150) based on the first motor control technique. The method further includes determining, using the motor controller (224), a change from the first load point to a second load point and determining, using the motor controller (224), a second motor control technique corresponding to the second load point. The method includes driving the motor (150) based on the second motor control technique.

A controller of a power tool outputs a driving signal to a motor driving circuit and acquires a position of a rotor of a brushless motor. While acquiring the position of the rotor of the brushless motor, a phase voltage or a line voltage of a winding of the brushless motor is detected through the voltage detection circuit. Whether an upper bridge arm switching element, a lower bridge arm switching element, and/or the brushless motor is short-circuited is determined according to the phase voltage or the line voltage of the winding of the brushless motor

A data storage device is disclosed comprising a head actuated over a disk, and a spindle motor configured to rotate the disk. A pulse width modulated (PWM) control signal is generated having a frequency based on a PWM clock, the spindle motor is controlled using the PWM control signal, and a frequency of the PWM clock is swung between a minimum frequency and a maximum frequency at a swing rate.

A power tool with a direct current, DC, power source comprising a controller for controlling a driver circuit driving a brushless motor in a power tool, the driver circuit being coupled to a direct current, DC, power source and including a first switching element pair coupled to a first phase winding of the brushless motor and a second switching element pair coupled to a second phase winding of the brushless motor; and the controller being arranged to alternately switch a first switching element of the first switching element pair and a second switching element of the second switching element pair, wherein the first switching element and the second switching elements are coupled to a respective terminal of the DC power source. A power tool comprising such a controller, and a method of controlling a driver circuit driving a brushless motor in a power tool.

In the position sensorless control method in low-speed region of the fault-tolerant permanent magnet motor system based on the envelope detection and the non-orthogonal phase-locked loop of the present disclosure, the position sensorless control of the motor is implemented by injecting the high-frequency voltage signals into any two non-faulty phase windings of the motor, extracting the high-frequency response currents of the high-frequency injected phases by the digital bandpass filter, calculating the differential mode inductances of the two phase windings through the envelope detecting and signal processing, and extracting the rotor position and rotational speed signals from the estimated two phase inductances through the non-orthogonal phase-locked loop. In addition, the controller of the present disclosure is small in size, high in accuracy, and high in reliability, which can effectively meet the performance requirements of the onboard electric actuators.

A motor driving circuit includes a rotation speed request generator, a motor driving signal generating unit, an inverter circuit, a position detecting circuit, a current detecting module, a rotation speed signal lookup module, an automatic leading angle controller, and a modulation signal generating circuit. When the rotation speed request signal indicates that a rotation speed of a motor is adjusted to a current rotation speed, the rotation speed signal lookup module queries a lookup table and generates a leading angle indication signal for indicating a current leading angle as a adjusting angle, and the automatic leading angle controller generates a phase adjusting signal, and the modulation signal generation circuit roughly adjusts a modulation waveform with the adjusting phase. The modulation signal generating circuit performs a fine adjustment on the modulation waveforms according to a phase difference, thereby making the current zero-crossing point near the BEMF zero point.

A data storage device is disclosed comprising a head actuated over a disk, and a spindle motor configured to rotate the disk. A pulse width modulated (PWM) control signal is generated having a frequency based on a PWM clock, the spindle motor is controlled using the PWM control signal, and a frequency of the PWM clock is swung between a minimum frequency and a maximum frequency at a swing rate.