1442results about "Multiple motor speed/torque control" patented technology

The present invention relates to a method for control of a direct current motor in one or several fan units, each comprising a fan, which method comprises: generation of a control signal from a first control unit which is external in relation to the said fan unit; transmission of the said control signal to the said fan unit; reception of the transmitted control signal in the said fan unit; interpretation of the said control signal in a second control unit which is arranged in association with the said fan unit; and generation, in the said second control unit, of a supply signal for the said direct current motor, on the basis of the control signal generated by the first control unit and received in the fan unit and on the basis of a supply voltage. According to the invention, the method comprises transmission of the control signal together with the supply voltage over a shared communication link, with the control signal being superposed on the supply voltage. The invention also relates to an arrangement for such control. By means of the invention, improved control is obtained of a motor that can be utilized in a ventilated seat in a vehicle.

An H-bridge circuit is connected to a coil of the vibration motor that is to be driven. A comparator receives Hall signals indicating position information of a rotor of the vibration motor, and converts to an FG signal. A pulse width modulator generates a pulse-modulated pulse signal specifying energization time of the coil of the vibration motor. The pulse width modulator, in a first mode, after commencing start-up of the vibration motor, sets a duty ratio of the pulse signal to 100%, and after that, switches the duty ratio to a predetermined value in accordance with rotational frequency of the motor. In a second mode, the duty ratio of the pulse signal continues to be set to 100%. In a third mode, frequency and the duty ratio of the pulse signal are set based on a control signal of a pulse form inputted from outside. The control signal is used also in switching mode.

Various embodiments of an electric motor and electronic control for an electric motor are disclosed. An exemplary electric motor comprises a single-phase brushless permanent magnet electric motor. In exemplary embodiments, the electronic motor control is configured to commutate an electric motor at a frequency other than line frequency, perform pulse width modulation, and drive the electric motor with a drive waveform that approximates the counter-electromotive force of the motor.

Power conversion apparatus and methods are presented for providing electrical power to a grid or other load in which a synchronous machine is driven by a wind turbine or other prime mover to provide generator power to a switching type current source converter (CSC), with a current source rectifier (CSR) of the CSC being switched to provide d-axis control of the synchronous machine current based on grid power factor feedback, and with a current source inverter (CSI) of the CSC being switched to provide leading firing angle control and selective employment of dumping resists to dissipate excess generator energy in a fault mode when a grid voltage drops below a predetermined level.

An electrical rotating apparatus is provided that has variable impedance. This is achieved by connecting one of the polyphase components of the apparatus in a mesh connection. The spanning value, L, of such a mesh connection may be varied by changing the harmonic content supplied by an inverter component. Also provided is a method for connecting an inverter to a motor, wherein a switching arrangement permits the simple alteration between various mesh connections of different span value, changing thereby the Volts / Hertz ratio of the motor.

A process to start a brushless direct current motor with a multiphase stator winding is disclosed, in which, during rotor standstill, a plurality of current impulses is intruded on the stator winding, the current rise time until a current threshold is reached is measured in the stator winding with every current impulse and the rotor position is derived from the measured current rise times. A more precise determination of rotor position is achieved with lower control-related effort for a regulated sensorless start-up in that a plurality of test current impulses is successively intruded on the stator winding in such a way that the test current impulses generate stator flow vectors offset by the same angular increments over 360° electrically in the stator. The current rise time for each stator flow vector is measured in the total current of the stator winding and the phase position of the stator flow vector with the smallest current rise time is determined as the rotor position.