A method for assisting in operating a PWM driven motor comprising for at least one phase of the PWM driven motor: generating a pulse width modulated phase voltage scheme according to a desired phase profile with a base scaling factor, by time multiplexing a first pulse and at least a further pulse within a pulse width modulation period of the phase the first pulse having a pulse width according to a first profile, for that rotor position, multiplied with a first scaling factor, the first profile being in phase with the desired phase profile, and the at least a further pulse having a pulse width corresponds with a further profile, for that rotor position, multiplied with a further scaling factor, the further profile being not in phase with the desired phase profile, whereby the first pulse and the at least one further pulse are positioned within the pulse width modulation period of the phase in at least partially non-overlapping way.

A method for controlling a three-phase brushless DC motor including a single hall sensor, the method including: A) measuring a deviation angle θ of a mounting position of the single hall sensor and storing; B) starting the motor: outputting six-path PWM signals by the microprocessor to control the operation of the inverter and allowing the single hall sensor to continuously and stably measure a position signal; C) obtaining a rotating angular velocity ω=360°/T in the last 360° electric angle cycle by the microprocessor; D) calculating a real-time position angle α=ωt+θ of a present 360° electric angle cycle by the microprocessor; and E) outputting the six-path PWM signals by the microprocessor to control the operation of the inverter so as to simultaneously energize the three-phase winding (U, V, and W); and switching a current direction of each winding.

An electric power steering apparatus that calculates a current command value based on at least a steering torque, performs a PWM-control of a brushless motor by an inverter based on the current command value, performs a current control by detecting a rotational angle of the brushless motor, and performs an assist-control of a steering system. The apparatus includes three rotational angle detecting systems to detect three rotational angles of the brushless motor; and an angle diagnosing section that compares absolute values of differences on respective angles outputted from the three rotational angle detecting systems with a threshold, and performs a process by diagnosing whether the rotational angle detecting systems are normal or abnormal; wherein the assist control is continuously performed by using output angles outputted from systems diagnosed as being normal.

A back electromagnetic force detection circuit detects a counter EMF generated in a coil of a stepping motor. A revolution count detection circuit generates a revolution count detection signal. A determining circuit generates a determination signal that is asserted if the revolution count detection signal is stable across multiple consecutive cycles. A current value setting circuit generates a current setting value indicating a target value of a coil current. The current value setting circuit sets the current setting value to a predetermined value in a period in which the determination signal is negated, and adjusts the current setting value according to the counter EMF in a period in which the determination signal is asserted. A constant current chopper circuit generates a pulse modulation signal that modulates by way of having a detection value of a coil current approach close to a target value of the current setting value.

A permanent-magnet synchronous machine comprises a rotor and a stator for holding at least one first stator winding and a second stator winding which is electrically insulated from said first stator winding. The second stator winding has a smaller conductor cross section and a larger number of turns than the first stator winding, wherein a first operating voltage is provided for motor operation of the first stator winding and a second operating voltage is provided for motor operation of the second stator winding. The second operating voltage has a higher rated voltage than a rated voltage of the first operating voltage.

An electronically commutated motor is operated from a DC voltage source (U.sub.B), e.g. from a DC link circuit (46). The motor has a permanent-magnet rotor (28) and a stator having a stator winding strand (26) in which, during operation, an alternating voltage is induced by the permanent-magnet rotor (28). It further has an H-bridge circuit (22) having power semiconductors (T1 to T4). At the beginning of a commutation operation, the presently conductive semiconductor switch of a first bridge half (38) is switched off, in order to interrupt energy delivery from the DC voltage source (U.sub.B), so that, in the other bridge half (56), a loop current (i*; −i*) flows through the stator winding strand (26), through the semiconductor switch still controlled to be conductive therein, and through a recovery diode (58; 60) associated with the blocked semiconductor switch of that other bridge half. This loop current converts the energy stored in the magnetic circuit of the motor (20) at least partly into driving energy for the permanent-magnet rotor (28), and in that context the stored energy drops to zero. This currentless state of the stator winding strand (26) is detected in a sensorless manner by measuring the voltage (u.sub.ind) induced by the rotor (28) in the stator winding strand (26).

A motor includes a stationary structure, and a rotor rotatable about a central axis with respect to the stationary structure. The stationary structure includes a stator including a coil, a bracket that supports the stator, and a circuit board disposed between the stator and the bracket. The bracket includes a board support that holds the circuit board between the bracket and the stator in an axial direction. The board support includes a wiring through hole that penetrates the board support in the axial direction and through which a wire extending from the circuit board passes, a lid that partially covers the wiring through hole, and a guide bridge that is located inside the wiring through hole when viewed in the axial direction and holds the wire between the lid and the guide bridge.

Embodiments of the present disclosure provide a method for controlling a fan, a system, and an air conditioner. The method includes: turning off a first bridge arm group in an inverter of the fan; applying a preset driving signal to a second bridge arm group in the inverter; detecting an electrical signal of a stator of the fan after the preset driving signal is applied; determining an initial state of the fan according to the electrical signal of the stator of the fan, wherein the initial state of the fan includes a downwind forward state, a static start state, or an unwind reverse state; and providing the fan with a control signal matching the initial state of the fan according to the initial state of the fan.

A motor unit comprises a motor controller, a motor, and a Hall sensor, where the motor controller is used for driving the motor. The motor controller comprises a switch circuit, a control unit, a phase signal generating unit, and an operational amplifier. The control unit generates a plurality of control signals to control the switch circuit. The motor comprises a rotor, a silicon steel plate, and a coil. To increase a success rate of starting a forward rotation, the silicon steel plate may have an asymmetrical structure, such that a fan blade is inclined to a forward rotation direction in a still state. When a Hall voltage is zero, the motor controller may start the motor and switch phases.

A trigger apparatus for a powered device, such as a power tool is disclosed. The powered device comprises a trigger operable by a user to move from a first position to at least one second position so as to control an operation of the powered device. The trigger apparatus comprises: a linear Hall effect sensor for measuring a change in a magnetic field associated with the trigger being moved from the first position to the at least one second position, and configured to generate a sensor signal based on the measured magnetic field, for controlling the operation of the powered device; a power module configured to power, the linear Hall effect sensor, upon reception of an activation signal for indicating that the trigger apparatus is to be activated; and an activation switch configured to generate the activation signal, when the trigger is moved from the first position. A powered device comprising the trigger apparatus and a method of controlling an operation of a powered device are also disclosed.