A system and method for controlling an electric machine via an inverter comprises an speed estimator that is configured to estimate a rotor speed of an electric motor to determine whether to control the inverter to operate the electric motor in a first mode or a second mode. For example, the first mode comprises a current-frequency control mode and the second mode comprises a back electromagnetic force (BEMF) mode. An electronic data processor or controller is configured to determine a first (current) command associated with a first mode of operating the electric motor, if the estimated rotor speed is a less than a speed threshold. The electronic data processor or controller is configured to determine a second (current) command associated with a second mode of operating the electric motor if the estimated rotor speed is equal to or greater than the speed threshold.

A system and method for controlling an electric machine via an inverter comprises an speed estimator that is configured to estimate a rotor speed of an electric motor to determine whether to control the inverter to operate the electric motor in a first mode or a second mode. For example, the first mode comprises a current-frequency control mode and the second mode comprises a back electromagnetic force (BEMF) mode. An electronic data processor or controller is configured to determine a first (current) command associated with a first mode of operating the electric motor, if the estimated rotor speed is a less than a speed threshold. The electronic data processor or controller is configured to determine a second (current) command associated with a second mode of operating the electric motor if the estimated rotor speed is equal to or greater than the speed threshold.

Unique systems, methods, techniques and apparatuses of a synchronous reluctance machine (SynRM) control are disclosed. One exemplary embodiment is a control device structured to operate a converter coupled to a synchronous reluctance machine and receive measurements of current. The device comprises a converter controller structured to detect a power supply restoration, operate the converter so as to transmit a series voltage vectors relative to the stationary reference frame to the stator of the synchronous reluctance machine, receive current measurements following the transmission of each of the voltage vectors, estimate the rotor position using the characteristics of the voltage vector and the received current measurements corresponding to at least one voltage vector, estimate the rotor speed using the characteristics of the voltage vectors and the received current measurements corresponding to at least two voltage vectors, and operate the converter so as to apply voltage to the stator.

Unique systems, methods, techniques and apparatuses of a synchronous reluctance machine (SynRM) control are disclosed. One exemplary embodiment is a control device structured to operate a converter coupled to a synchronous reluctance machine and receive measurements of current. The device comprises a converter controller structured to detect a power supply restoration, operate the converter so as to transmit a series voltage vectors relative to the stationary reference frame to the stator of the synchronous reluctance machine, receive current measurements following the transmission of each of the voltage vectors, estimate the rotor position using the characteristics of the voltage vector and the received current measurements corresponding to at least one voltage vector, estimate the rotor speed using the characteristics of the voltage vectors and the received current measurements corresponding to at least two voltage vectors, and operate the converter so as to apply voltage to the stator.

A method for determining a stator current vector for starting a synchronous machine of a drive of a passenger transportation apparatus having a rotor and a stator with a stator winding may involve imposing different stator current vectors with different stator current vector directions on the stator winding over the course of a plurality of current application operations, determining from the different stator current vectors a minimum stator current vector with a minimum stator current vector direction at which a minimum driving torque acting on the rotor is generated in the synchronous machine, determining a starting stator current vector with a starting stator current vector direction from the minimum stator current vector, and imposing the starting stator current vector on the stator winding for starting the synchronous machine.

A method for determining a stator current vector for starting a synchronous machine of a drive of a passenger transportation apparatus having a rotor and a stator with a stator winding may involve imposing different stator current vectors with different stator current vector directions on the stator winding over the course of a plurality of current application operations, determining from the different stator current vectors a minimum stator current vector with a minimum stator current vector direction at which a minimum driving torque acting on the rotor is generated in the synchronous machine, determining a starting stator current vector with a starting stator current vector direction from the minimum stator current vector, and imposing the starting stator current vector on the stator winding for starting the synchronous machine.

A method, system, and apparatus are provided for determining mechanical characteristics of an electric motor and mechanical load with a speed signal modulator, FOC current loop, sensor-less rotor speed estimator, and speed signal demodulator which are configured to provide a q-axis AC reference current, q-axis DC reference current, estimated maximum AC rotor speed, estimated DC rotor speed, estimated phase angle of the AC rotor speed component, and torque constant to a mechanical characteristics estimator which is configured to determine a plurality of load torque parameters for the electric motor and mechanical load which include a combined moment of inertia parameter, a combined static friction, and a combined viscous friction coefficient parameter.

A method, system, and apparatus are provided for determining mechanical characteristics of an electric motor and mechanical load with a speed signal modulator, FOC current loop, sensor-less rotor speed estimator, and speed signal demodulator which are configured to provide a q-axis AC reference current, q-axis DC reference current, estimated maximum AC rotor speed, estimated DC rotor speed, estimated phase angle of the AC rotor speed component, and torque constant to a mechanical characteristics estimator which is configured to determine a plurality of load torque parameters for the electric motor and mechanical load which include a combined moment of inertia parameter, a combined static friction, and a combined viscous friction coefficient parameter.

An apparatus according to the aspect of the embodiments includes a phase determiner configured to determine a rotational phase of a rotor, a speed determiner configured to determine a rotational speed of the rotor, a controller having a first control mode for controlling the motor by supplying constant currents to windings, and a discriminator configured to discriminate whether a rotation of the motor is abnormal based on the rotational speed when the rotational speed corresponding to a command speed is equal to or higher than a predetermined value in a state where the controller is controlling the motor in the first control mode. When a signal output from the discriminator indicates that the rotation of the motor is abnormal, the controller stops the motor. When the signal output from the discriminator indicates that the rotation is not abnormal, the controller continues a drive of the motor.

A motor driving apparatus including a motor including a stator and a rotor rotating in the stator, an inverter configured to supply a driving voltage to a stator coil wound on the stator so as to rotate the rotor, and a control unit configured to, when a target command value is received, change a predetermined reference start-up time point to a start-up time point corresponding to an electrical angle position of the rotor in correspondence with the target command value per rotation of the rotor and to control the inverter to supply the driving voltage at the start-up time point.