A rotary impact tool includes an impact assembly, a brushless motor, a transmission assembly, a drive circuitry, and a controller. The controller is configured to acquire a commutation interval of the brushless motor, output a first control signal to the drive circuitry causing the brushless motor to operate at a preset initial speed, and output a second control signal to the drive circuitry to gradually increase a rotational speed of the brushless motor to a preset final speed, when a commutation interval of the brushless motor becomes greater than or equal to a preset time threshold, where the preset initial speed is less than the preset final speed.

A filter for use with a brushless DC motor to filter a signal received from a floating terminal of the brushless DC motor, wherein the filter is configured such that a time delay introduced by the filter to the signal received from the floating terminal is equal to the time taken for a rotor of the motor to rotate through an angle equal to half of a commutation step of the motor.

A vehicle performs first PWM control of generating a first PWM signal of a plurality of switching elements to switch the plurality of switching elements by comparing voltage commands of phases based on a torque command with a carrier voltage when a target operating point including a rotation speed and the torque command of the motor is outside a predetermined area, and selects and performs second PWM control of generating a second PWM signal of the plurality of switching elements to switch the plurality of switching elements based on a modulation factor of a voltage and a voltage phase based on the torque command and the number of pulses in a predetermined period of an electrical angle of the motor or the first PWM control when the target operating point is inside the predetermined area.

A control apparatus controlling an opening and closing member for a vehicle includes a drive control unit operating an opening and closing member of the vehicle by a motor serving as a drive source, and a catch detection unit detecting a catch of a foreign object caught by the opening and closing member in response to a current value of the motor. The drive control unit includes a motor control signal output unit outputting a motor control signal for supplying a drive power to the motor, and an advance-angle value setting unit setting an advance-angle value for advancing a phase of the motor control signal. The advance-angle value setting unit includes an advance-angle value increase prohibition unit prohibiting increase setting of the advance-angle value in a case where the current value of the motor reaches an advance-angle value increase prohibition current value.

The method is for making an electric motor more efficient by iteratively changing when a processor sends activation signals to transistors to minimize a current required to rotate a rotor at a constant rotational speed. The method is also for changing a rotational direction of the rotor by switching the order in which activation signals are sent to the transistors.

The present invention is a high efficiency permanent magnet machine capable of maintaining high power density. The machine is operable over a wide range of power output. The improved efficiency is due in part to copper wires with a current density lower than traditional designs and larger permanent magnets coupled with a large air gap. In a certain embodiment wide stator teeth are used to provide additional improved efficiency through significantly reducing magnetic saturation resulting in lower current. The machine also has a much smaller torque angle than that in traditional design at rated load and thus has a higher overload handling capability and improved efficiency. In addition, when the machine is used as a motor, an adaptive phase lag compensation scheme helps the sensorless field oriented control (FOC) scheme to perform more accurately.

A current controller for an electric machine that includes an input, an output, a threshold generator and a comparator. The threshold generator stores a scaling factor and includes a PWM module that operates on a reference voltage to generate a threshold voltage. The duty cycle of the PWM module is then defined by the scaling factor. The comparator compares a voltage at the input against the threshold voltage and causes an overcurrent signal to be generated at the output when the voltage at the input exceeds the threshold voltage.

A motor drive controller includes: a motor driver that applies a voltage to each phase of a motor to rotate; a rotational position detector that detects rotational position of the motor and generates rotational position information indicating the rotational position; and a controller that outputs, to the motor driver, driving control signals for repeatedly adjusting an advance angle and a lag angle at energization switching of the each phase of the motor in a prescribed pattern based on the rotational position information generated by the rotational position detector.

The present invention relates to a method of commutation control of a BLDC motor. The method uses a controller to control the BLDC motor using a modified six-step commutation. The method adds six intermediate steps that overlap the six-step commutation. Each of the six steps overlap with preceding and following steps, resulting in six additional intermediate steps in which all three phases are active. By doubling the number of steps, current and torque will vary less over time compared with current solutions without increasing the size or changing the design of the motor.

Basic current commands of a d-axis and a q-axis are set based on a torque command of a motor. Subsequently, when the rotation speed of the motor is high, an electric angle compensation amount is set to be larger than that when the rotation speed of the motor is low, and a corrected predicted electric angle is set by adding the electric angle compensation amount to a predicted electric angle predicted from an electric angle based on a rotation position of a rotor of the motor from a rotation position detection sensor. Then, current commands of the d-axis and the q-axis are set by multiplying the basic current commands of the d-axis and the q-axis by a correction coefficient based on the corrected predicted electric angle, and an inverter is controlled using the current commands.