A method for determining the angle of the rotor of an electric motor includes receiving a first rotor position signal from a rotor position sensor by using a control unit, the first rotor position signal including a plurality of orders; determining the angular velocity of the electric motor at least by way of the first rotor position signal by using an angular velocity module of the control unit; determining a first base signal by way of the determined angular velocity and the first rotor position signal by using a first filter module of the control unit; and determining the angle of the rotor at least by way of the determined first base signal by using an angle module of the control unit.

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.

Methods and apparatus for determining a position of a rotor in motor, such as a three-phase motor by determining first and second ones of sectors in which a first one of the magnetic poles of the rotor may be positioned by driving phase pairs with complementary signals and examining a voltage of a floating one of the phases. Embodiments can further include driving first and second currents towards the first and second ones of the sectors and analyzing a time for each of the first and second currents to reach a threshold to identify which of the first and second ones of the sectors is aligned with the first one of the magnetic poles of the rotor.

A method for operating a brushless direct current motor wherein, by the energization of a plurality of armature coils which are arranged on a stator and form a three-phase current winding for generating a rotating field which rotates around the stator, and having three terminals, a rotating field is generated in order to drive a rotor, which is rotatable about an axis of rotation relative to the stator and has at least two opposing permanent magnet poles. For the determination of the position of the rotor relative to the stator a measurement voltage signal is applied between a first and second of the terminals, a resulting voltage is measured on a third of the terminals, a gradient value which indicates the gradient of the resulting voltage in a time interval is determined with reference to the progression over time of the resulting voltage.

A motor control system includes an inverter and a plurality of current sensors each positioned in-line between the inverter and a phase coil of the motor. Each current sensor measures the current provided to each phase coil of the motor and provides a signal indicative of each phase current to a controller. In some embodiments, the currents sensors are provided as one or more current sense integrated circuits. A protection circuit protects the current sense integrated circuit from ground bounce by coupling a diode and an opposite facing Zener diode in series between the power supply pin and the ground pin of the integrated circuit.

A motor control system includes an inverter and a plurality of current sensors each positioned in-line between the inverter and a phase coil of the motor. Each current sensor measures the current provided to each phase coil of the motor and provides a signal indicative of each phase current to a controller. In some embodiments, the currents sensors are provided as one or more current sense integrated circuits. A protection circuit protects the current sense integrated circuit from ground bounce by coupling a diode and an opposite facing Zener diode in series between the power supply pin and the ground pin of the integrated circuit.

In a method for determining the rotor position of a three-phase machine without using a rotary encoder, and to a device for controlling a three-phase motor without using a rotary encoder, the three-phase machine is fed by a converter that can be operated by pulse-width modulation, and the converter has model variables for the rotor angle and the current indicator of the three-phase machine, and the converter has device(s) by using which, in control operation, at least two values are measured which represent a measure of the local inductances of the machine which represent a measure of the local inductances of the machine, the error of the model rotor angle is determined in that, depending on the model rotor angle and the model current indicator, at least two weighting factors are determined, and in that a weighted sum is formed from the at least two measured values and the at least two weighting factors, and in that a further offset value is substracted from the sum, which is likewise determined on the basis of the model rotor angle and the model current indicator.

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 system and method for torque compensation in a switched reluctance (SR) machine disposed on a machine is disclosed. The system may comprise a SR machine, an inverter and a controller. The controller is in operable communication with the inverter and is configured to determine a commanded main current associated with energization by a main current of a first portion of the plurality of windings for a controlling phase, and determine a commanded parasitic current associated with energization by a parasitic current of a second portion of the windings in a non-controlling phase. The controller is further configured to determine an offset current based on the commanded parasitic current, and determine a target current based on a first sum of the commanded main current and the offset current, and command the inverter to actuate the target current in the first portion of the windings during the controlling phase.

A method and device for acquiring a rotor position based on a permanent magnet synchronous drive system. The permanent magnet synchronous drive system includes an inverter and a permanent magnet synchronous motor, wherein the initial speed of the permanent magnet synchronous motor is not zero. The method includes: controlling a bridge arm switch of an inverter periodically; collecting a three-phase current of the permanent magnet synchronous motor at a fixed time within each control period; and after the three-phase current is reversed, sending same to a phase-locked loop system to conduct processing, so as to obtain a phase angle of an induction potential vector, and according to the phase angle of the induction potential vector, acquiring a rotor position angle of the permanent magnet synchronous motor.