An electronic switch control method is disclosed. The method comprises receiving the current working parameters of the electronic switch, then reading duty cycle parameters matching with the current working parameters; conducting a linear calculation with the duty cycle parameters and the working parameters to obtain a new duty cycle; adjusting the current control signal to obtain a PWM signal having the new duty cycle; and controlling the rotation speed of the motor in a load with the PWM signal. By reducing the volume of an electronic switch and achieving a long low-speed travel, the disclosure enables the user to work at an accurate working point with an electronic device.

A closed-loop system may include a plant (an electric machine requiring control) and a fractional-order proportional-resonant controller. The fractional-order proportional-resonant controller may have an order greater than zero and less than or equal to one. The order for the fractional-order proportional-resonant controller may be selected to yield a target amplitude and target slope for frequency response. The frequency response may be such that a steady-state error associated with a speed of the electric machine is inversely proportional to the target amplitude and less than a predetermined threshold. The order of the controller may be 0.9.

Provided herein is a BLDC motor having a control system, a rotor including a motor magnet having a plurality of alternating magnetic poles thereon, a stator and a ring magnet. The ring magnet is mounted on the rotor axially adjacent the motor magnet. The number of poles on the ring magnet is an integer multiple of the number of poles on the motor magnet. Also provided is a method for controlling the BLDC motor including the steps of supplying a current to the motor, determining if the torque produced by the motor is in a positive or negative direction, determining a multiplier based on the direction of the torque, multiplying the supplied current by the multiplier, implementing a commutation sequence to provide current to the motor, measuring the current in each of the plurality of windings and adjusting the current provided to the motor based on the measured current.

An air-cooled heat exchanger (ACHE) for cooling process fluids used in an industrial process. In one embodiment, the ACHE is configured as a forced-draft ACHE. A support structure supports the forced draft ACHE above grade. A tube bundle is supported by the structure and is configured to receive process fluids used in an industrial process. A plenum is connected to the support structure, positioned beneath the tube bundle and configured to direct air-flow through the tube bundle. A fan is supported by the support structure and positioned beneath the plenum. Rotation of the fan produces an air-flow that is directed through the tube bundle by the plenum. A fan drive system is supported by the support structure, positioned beneath the fan and comprises a permanent magnet motor comprising a motor casing, a stator and a rotatable shaft, the rotatable shaft being connected to the fan.

When the current flowing through each electric terminal of an AC motor 21 reaches the vicinity of zero, an operation putting the electric terminals of the AC motor 21 into an opened state, or putting an electric terminal into a conductive state via a reflux diode inside an inverter 11, is carried out. Herein, as an operation such that the current flowing through each electric terminal reaches the vicinity of zero, the electric terminals are short-circuited by all upper arm or lower arm switching elements of the inverter 11 being turned on. By so doing, a flow of electromagnetic energy of a reactance component of the AC motor 21, from the AC motor 21 into the inverter 11 side when the drive of the inverter 11 is stopped, is prevented or suppressed. As a result of this, an overvoltage or overcurrent is prevented.

Control apparatus and corresponding method for controlling a high power electric motor, preferably of the order of megawatts, preferably of or associated with a shredding plant which is preferably usable for shredding very bulky and heavy objects and is provided with a rotating shredding member connected to the rotor of the electric motor, where a control circuit is configured to control the electric motor so that it can operate selectively in different operating modes.

A motor control device of the present invention supplies a detection current to a motor at predetermined time intervals, detects a voltage between the both ends of a smoothing capacitor when the detection current is supplied, and determines whether a connector is inserted or unplugged based on a change in the voltage between the both ends of the smoothing capacitor. Furthermore, if determining that the connector is unplugged, the motor control device decreases the voltage between the both ends of the smoothing capacitor to or below a defined value by discharging the smoothing capacitor.

A rotation speed control method and device of a motor, and a motor control system; the rotation speed control method of the motor comprises the following steps: conducting differential regulation on the output rotation speed of the motor to generate a feedback rotation speed signal (S1); generating a rotation speed deviation signal according to a target rotation speed signal and the feedback rotation speed signal (S2); conducting proportional integral regulation on the rotation speed deviation signal to generate a rotation speed control signal (S3); and controlling the rotation speed of the motor according to the rotation speed control signal (S4). The rotation speed control method, the rotation speed control device and the motor control system run steadily and have good dynamic performance, and are easy to implement.

A system for controlling an electric motor which includes three coils and a rotor, comprising a motion-profile-generator for generating a rotor-motion-profile and for producing a position-command, a position-controller for determining a velocity-command and a position-feedforward, for determining a forward-velocity according to the prediction of the velocity required to reach said posit ton-command. The system further includes a first summer for producing a modified velocity, a velocity controller, for determining a current-command, a velocity feedforward, for determining a forward-current and a second summer for producing a modified-current. The system also includes a commutator, for determining respective modified-coil-currents for each of at least three current-control-loops and for dividing said modified-coil-currents between the said current-control-loops according to the position of said rotor. Each current-control-loop includes a current-controller, for determining a respective voltage-command for the respective coil thereof an h-bridge for providing said voltage command to the respective coil thereof.

A controller for controlling a micromechanical actuator having a setpoint input for receiving a setpoint signal, an actual-value input for receiving an actual-value signal, a setpoint filter to attenuate a first predefined frequency or a first predefined frequency band in the received setpoint signal to generate a filtered setpoint signal, a differentiator to generate a time derivative of the received actual-value signal; a controller core to generate a manipulated variable signal based on a system deviation between the filtered setpoint signal and the actual-value signal; a phase rotation element to modify the phase of the difference between the manipulated variable signal and the derivative of the actual-value signal for a second frequency or in a predefined second frequency band to generate a modified manipulated variable signal; and a first manipulated variable filter to suppress a predefined third frequency in the modified manipulated variable signal.