A system for controlling an electric motor including a rotor supported by a lubricant upon a stator with a plurality of stator poles and stator windings includes monitoring a radial position and rotor angle of the rotor by a controller. The system includes generating adjustments by the controller to cause the stator poles to apply a net radial force to the rotor. This net radial force may be used, for example to cause the rotor to be centered upon a central axis of the electric motor and may be particularly advantageous for a lubricant supported rotor. A motor drive provides an AC current to the stator windings as well as phase current adjustments of the electrical current in one or more of the stator windings to apply the net radial force to the rotor in a direction perpendicular to the drive axis.

Methods and control apparatus for operating a three-phase electric motor are described, in which the motor windings are switched between Star and Delta connections depending on torque requirements, and in which the motor windings are switched to a braking mode when braking torque is required. The electromagnetic torque of the motor is monitored, and a command to switch from Star to Delta is given when the electromagnetic torque rises to reach or exceed a threshold.

A circuit for a smart safety system includes an electrical input connection to obtain power from a power source and an electrical output connection to regulate the power to an AC motor. The circuit also includes an adjustable DC power supply. One or more electronic switching devices regulate electricity output to the AC motor. The circuit has one more functional states including: a first state, activated via a first electrical signal, in which electricity is supplied to AC motor to allow normal operation of the AC motor, and a second state, activated via a second electrical signal, in which no electricity is supplied to the AC motor to prevent unintentional operation of the AC motor.

A method for reducing a total operational load of a method of a model predictive control-by conducting simplifications based on specific observations, in order to drive alternating current motors by using the method of the MPC with a two-level voltage source inverter. The method includes the steps of determining at which one of the predefined sectors a resultant of stator currents is present, determining a motor mode, reducing seven estimation vectors to four estimation vectors and calculating a cost function or reducing seven estimation vectors to five estimation vectors and calculating the cost function.

A reduced voltage soft starter (RVSS) includes a switching circuit configured to selectively couple an AC power source to a motor and a control circuit configured to sense a line voltage provided to the switching circuit to produce a first voltage signal, to sense a current of the motor to generate a current signal and to generate a second voltage signal representative of a voltage of the motor responsive to the first voltage signal and the current signal. The control circuit may be further configured to generate an estimate of a torque of the motor responsive to the second voltage signal and to control the torque of the motor responsive to the torque estimate.

A device and method for determining operating modes of an AC asynchronous three-phase motor in an escalator system and computer-readable storage medium on which a computer program for implementing the method is stored. The operating modes include a first operating mode and a second operating mode, the AC asynchronous three-phase motor adopts a triangular wiring mode and a star wiring mode in the first operating mode and the second operating mode, respectively, the device includes: a memory; a processor coupled with the memory; and a computer program stored on the memory and running on the processor, the running of the computer program causes: A. obtaining a slip rate of the AC asynchronous three-phase motor; and B. determining whether the AC asynchronous three-phase motor needs to be switched between the first operating mode and the second operating mode based on the slip rate.

A device and method for determining operating modes of an AC asynchronous three-phase motor in an escalator system and computer-readable storage medium on which a computer program for implementing the method is stored. The operating modes include a first operating mode and a second operating mode, the AC asynchronous three-phase motor adopts a triangular wiring mode and a star wiring mode in the first operating mode and the second operating mode, respectively, the device includes: a memory; a processor coupled with the memory; and a computer program stored on the memory and running on the processor, the running of the computer program causes: A. obtaining a slip rate of the AC asynchronous three-phase motor; and B. determining whether the AC asynchronous three-phase motor needs to be switched between the first operating mode and the second operating mode based on the slip rate.

Provided are a controller and a program with which it is possible to easily output the state of mechanical loss in an induction motor. A controller for controlling industrial machinery that has an induction motor comprises: an electric power cutoff unit that cuts off the supply of electric power to the induction motor; a speed acquisition unit that acquires the speed of the induction motor; an acceleration calculation unit that calculates acceleration on the basis of the acquired speed; a moment-of-inertia acquisition unit that acquires the moment of inertia of a spindle of the induction motor; a mechanical loss calculation unit that calculates mechanical loss in the induction motor on the basis of the acquired speed, the calculated acceleration, and the acquired moment of inertia; and an output unit that outputs the calculated mechanical loss.

A method and a control apparatus for determining parameters for controlling an electric drive having an electric machine improve the start-up of the electric drive by applying a current indicator as a signal at three-phase winding connections of the electric machine, and measuring a d-component and a q-component of the stator voltage and of the stator current at the winding connections. In a first measurement step, a rotating current indicator is applied to the three-phase winding connections and the electric machine is oriented such that an exciter current in the q-axis assumes a minimum. In a second measurement step, when the rotor of the electric machine is stationary, a field winding of the electrical machine is short-circuited and a current indicator in form of a binary noise signal is applied to the winding connections. A stator impedance is then determined as a first control parameter.

The present invention provides a method and system for controlling the temperature of an electric motor by adjusting the electric losses in the motor. In an embodiment, the required load on the motor is determined and a first motor voltage is provided to meet the required load. A predetermined temperature set point for the motor is compared against the temperature of the motor and based on the temperature of the motor and the predetermined temperature set point, a secondary motor voltage is determined. The motor voltage may then be adjusted based on the calculated voltage and the motor load measurement adjusted based on the measured motor speed and actual motor voltage.