A method is for operating a three-phase cage motor on a multiphase electrical grid via a soft starter, with which one or more grid phases of the grid being respectively switchable by firing thyristors. Apart from a grid-related firing criterion, a rotor-flux-related firing criterion is taken into account.

A motor driving method includes steps of: at an open loop phase and in response to a motor being operated under a steady-state, calculating an angle difference between an estimation coordinate axis of the motor and an actual coordinate axis by a controller, according to an estimation voltage value, an estimation current value and at least one electrical parameter feedback from the motor and in reference with the estimation coordinate axis of the motor; calculating an actual current value in reference with the actual coordinate axis according to the angle difference by the controller; calculating a load torque estimation value associated with the motor according to the actual current value by the controller; and, in response to the open loop phase being switched to a close loop phase, compensating an output torque of the motor according to the load torque estimation value by the controller.

A motor driving method includes steps of: at an open loop phase and in response to a motor being operated under a steady-state, calculating an angle difference between an estimation coordinate axis of the motor and an actual coordinate axis by a controller, according to an estimation voltage value, an estimation current value and at least one electrical parameter feedback from the motor and in reference with the estimation coordinate axis of the motor; calculating an actual current value in reference with the actual coordinate axis according to the angle difference by the controller; calculating a load torque estimation value associated with the motor according to the actual current value by the controller; and, in response to the open loop phase being switched to a close loop phase, compensating an output torque of the motor according to the load torque estimation value by the controller.

A control unit for operating an electrical machine which includes a rotor, a stator, and power electronics. The power electronics have a plurality of switching elements, by which the phases of the stator winding are connected/connectible electrically to an electrical energy store. The control unit includes first and second processing units and is configured to determine control signals for controlling the switching elements, using the processing units. The first processing unit is configured to determine a magnitude of a setpoint voltage vector for the phases based on a setpoint rotational speed of the rotor and an actual rotational speed of the rotor. The second processing unit is connected to the first processing unit so as to be able to communicate with it, and being configured to determine the control signals as a function of the magnitude of the setpoint voltage vector and an actual angle of rotation of the rotor.

A control unit for operating an electrical machine which includes a rotor, a stator, and power electronics. The power electronics have a plurality of switching elements, by which the phases of the stator winding are connected/connectible electrically to an electrical energy store. The control unit includes first and second processing units and is configured to determine control signals for controlling the switching elements, using the processing units. The first processing unit is configured to determine a magnitude of a setpoint voltage vector for the phases based on a setpoint rotational speed of the rotor and an actual rotational speed of the rotor. The second processing unit is connected to the first processing unit so as to be able to communicate with it, and being configured to determine the control signals as a function of the magnitude of the setpoint voltage vector and an actual angle of rotation of the rotor.

A method for operating a brushless and sensorless multi-phase electric motor. At least two phase voltages and at least two phase currents of the electric motor are determined. A voltage vector is determined from the phase voltages and/or a current vector is determined from the phase currents. A position substitute signal is determined as a measure of a rotor position on the basis of an angle of the current vector and/or of the voltage vector. A rotation value is calculated on the basis of the position substitute signals, and the electric motor is controlled by open-loop and/or closed-loop technology on a basis of the rotation value.

A method for operating a brushless and sensorless multi-phase electric motor. At least two phase voltages and at least two phase currents of the electric motor are determined. A voltage vector is determined from the phase voltages and/or a current vector is determined from the phase currents. A position substitute signal is determined as a measure of a rotor position on the basis of an angle of the current vector and/or of the voltage vector. A rotation value is calculated on the basis of the position substitute signals, and the electric motor is controlled by open-loop and/or closed-loop technology on a basis of the rotation value.

A method for controlling an electrical motor taking in account slip frequency. The method including determining amplitude, phase and frequency of the stator voltage from voltage measurements, determining estimates for current components from current measurement and stator voltage phase, determining estimate for torque from voltage amplitude, frequency, current amplitude and motor data, determining estimate for speed from torque, frequency and motor data, and determining over-estimation of speed from speed estimate, torque estimate and slip frequency. The over-estimation may be used to improve functional safety of the motor.

A method for controlling an electrical motor taking in account slip frequency. The method including determining amplitude, phase and frequency of the stator voltage from voltage measurements, determining estimates for current components from current measurement and stator voltage phase, determining estimate for torque from voltage amplitude, frequency, current amplitude and motor data, determining estimate for speed from torque, frequency and motor data, and determining over-estimation of speed from speed estimate, torque estimate and slip frequency. The over-estimation may be used to improve functional safety of the motor.

Systems, computer readable media storing instructions, and computing device-implemented methods include receiving one or more signals that represent an angular speed of a permanent magnet electric motor of a hybrid electric vehicle, receiving a signal representing a voltage from the electric motor, determining if the angular speed is within a predetermined threshold, calculating an error angle representing a correction factor for an alignment of the electric motor based on a ratio of the voltage and the angular speed, determining if the error angle indicates that the motor is installed in a correct or an incorrect orientation, and adding an orientation correction factor to the error angle.