Modulating a gate drive current supplied to an output drive switch coupled to an electric motor by performing at least the following: obtain a gate drive current modulation profile, supply, based on the gate drive current modulation profile, a first gate drive current level as the gate drive current when the output drive switch is operating within a first region, drop the first gate drive current level to a second gate drive current level when the output drive switch transitions from the first region to operating within a Miller region, increase the second gate drive current level to a third gate drive current level within the Miller region, and set the gate drive current to a fourth gate drive current level when the output drive switch transitions from the Miller region to operating within a third region.

A motor controller includes: a rotation speed measurement portion that measures a rotation speed of a motor; and an energization method switching portion that switches an energization method so that the motor is driven by a 120-degree energization method when a rotation speed of the motor measured by the rotation speed measurement portion is less than or equal to a predetermined threshold value, and the motor is driven by a 150-degree energization method when a rotation speed of the motor measured by the rotation speed measurement portion exceeds the predetermined threshold value.

There are provided a brushless motor control device and a brushless motor control method that can suppress occurrence of step-out caused by reverse rotation, in low-speed sensorless control of a brushless motor. The brushless motor control device applies, to a brushless motor, a positive pulse generating torque in a rotation direction of the brushless motor and a negative pulse generating torque in a reverse rotation direction, and detects a rotation direction by using a magnetic saturation voltage generated when the positive and negative pulses are applied. The control device sets an upper limit value to a motor application duty represented by a value obtained by subtracting an application duty of the negative pulse from an application duty of the positive pulse.

A motor assembly for a switch drive of an electric switch. The motor assembly has a brushless three-phase motor and an electronic control device for controlling the three-phase motor. The control device has a rectifier unit for rectifying a supply voltage of the motor assembly if the supply voltage is an AC voltage, and for reverse polarity protection if the supply voltage is a DC voltage. The control device also has a voltage measuring unit for detecting a rectifier output voltage of the rectifier unit, a switch unit for generating a pulse width-modulated drive AC voltage for the three-phase motor from the rectifier output voltage, and a control unit for actuating the switch unit according to the rectifier output voltage.

The present application relates to an intelligent synchronous rectification system of an electronic speed controller, and a control method for the intelligent synchronous rectification system. The system comprises: a Hall sensor, a second control module, a three-phase inverter, a first control module, a freewheeling measurement module, and a power source module. By means of the present application, the effects of decreasing a rectification loss and ensuring operation smoothness are both achieved.

Circuitry for directly providing drive power to a BLDC motor having separated coils, comprising unipolar controlled current sources for supplying current to each of the separated coils; a controller, for controlling the level and phase of the unipolar controlled current sources; a polarity switch for converting the unipolar current to a bipolar (AC) current, supplied to the separated coils. The controller is adapted to shape the current being fed to the BLDC motor by the current source via the polarity switch, to be in phase with the back EMF sensed on the separated coils, and of a magnitude that corresponds to a required torque.

An electromagnetic interference reducing circuit is provided. A first random number generator generates a plurality of first random number signals each having a plurality of triangular waves. Each of the triangular waves has a plurality of steps. The first random number generator generates a plurality of first random numbers and modulates each of the first random number signals according to the first random numbers. The first random number generator repeatedly counts, repeatedly removes, or does not count time of the steps of each of the triangular waves of each of the first random number signals according to one of the first random numbers. A first oscillator generates a first oscillating signal. A motor controller circuit controls a plurality of switch components of a motor respectively according to the first random number signals based on the first oscillating signal.

A brushless bi-directional electric machine comprises a housing mounting exciting coils, a rotor and a stator, the exciting coils and the stator being stationary with respect to the housing and the rotor mounted for rotation with respect to the housing. The electric machine comprises a controller configured to control an exciting current supplied to the exciting coils.

A power tool includes a brushless motor including several windings, a drive circuit for driving the brushless motor, a detection device for detecting the brushless motor so as to obtain a load parameter corresponding to a load of the brushless motor, and a controller for outputting a first control signal to reduce current of the brushless motor in a first slope when the load parameter exceeds a first preset range.

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.