An electric motor is controlled using a feedback signal that includes an error between the measured current and the estimated current determined using the measured current, the measured voltage, and a model of the motor. A feedback gain is determined as an error function of a feedback signal and a speed of the motor is estimated using a product of the feedback gain and the feedback signal. The voltage of the motor is determined using a difference between the estimated speed of the motor and a reference speed of the motor and the motor us controlled using the determined voltage.

A system includes a permanent magnet motor having a rotor and a stator. The rotor and the stator have a configuration that causes the motor to generate a back-electromagnetic force (EMF) waveform that is substantially sinusoidal. The system also includes a motor controller having a sliding-mode observer configured to identify the back-EMF waveform and a position observer configured to estimate at least one characteristic of the motor using the identified back-EMF waveform. The stator may include multiple teeth projecting towards the rotor and multiple conductive windings, where each conductive winding is wound around a single tooth. The rotor may include multiple magnetic poles, where each magnetic pole has a span of about 60 or less. The sliding-mode observer may be configured to receive current measurements associated with three-phase signals and voltage commands generated by the motor controller. The position observer may include a proportional-integral (PI) regulator.

In described examples, a device includes a processor and a non-transitory memory storing instructions that, when executed, cause the processor to operate in an open loop mode a motor that includes a rotor and a stator. An angle error of the rotor is determined. In response to the angle error of the rotor being less than a threshold, the processor transitions from operating the motor in the open loop mode to operating the motor in a closed loop mode by changing from using a first coordinate system based on a command rotor position to using a second coordinate system based on an estimated rotor position to determine current vectors used to control the motor; and holding constant a current vector used to control the motor while performing the changing action. After performing the changing and holding actions, the processor operates the motor in the closed loop mode.

There is provided an apparatus for controlling a permanent magnet synchronous motor in a permanent magnet synchronous motor system. The apparatus comprises a disturbance observation circuit unit configured to estimate concentrated disturbance of the permanent magnet synchronous motor using a nonlinear observation gain function; and a sliding mode controller configured to control the permanent magnet synchronous motor by reflecting the estimated concentrated disturbance in a position-current single-loop control in which back-stepping control and sliding mode control are integrated.

At least one example embodiment discloses a method of estimating a position of a rotor in a motor. The method includes obtaining a current regulation quality index based on a current command and a measured current, determining an estimated position of the rotor based on the current regulation quality index and position estimation data and controlling the motor based on the estimated position of the rotor.

At least one example embodiment discloses a method of estimating a position of a rotor in a motor. The method includes obtaining a current regulation quality index based on a current command and a measured current, determining an estimated position of the rotor based on the current regulation quality index and position estimation data and controlling the motor based on the estimated position of the rotor.

A method for Field Oriented Control (FOC) of a Permanent Magnet Synchronous Motor (PMSM) with a constant Power Factor Control (PFC) Loop includes measuring a rotor position of the PMSM. A plurality of stator voltages of the PMSM is controlled with a required direct (d)-axis current, a required quadrature (q)-axis current, the rotor position and a plurality of measured stator currents of the PMSM in a three-phase stationary reference frame. The required d-axis current is determined with a required power factor, the plurality of measured stator currents transformed into two-phase stationary reference frame, the measured stator currents transformed into a rotational reference frame, and each of a required -axis voltage and a required -axis voltage transformed into the two-phase stationary reference frame, wherein a power factor of the PMSM is controlled to be equal to the required power factor.

A method is provided that may include receiving an identifier of a permanent magnet synchronous motor (PMSM), and mapping the identifier to electrical parameters of the PMSM. The method may include determining one or more coefficients of a sliding mode observer (SMO) based on the electrical parameters. The method may include providing the determined coefficients to the SMO to estimate the rotor position and speed of the PMSM.

A method for controlling a permanent magnet (PM) synchronous motor in an ESP application is provided. A load angle of the PM motor is estimated. A voltage adjustment value is determined for the PM motor based at least on the estimated load angle of the PM motor. A voltage to be applied to the PM motor is determined based on the voltage adjustment value.

In described examples, a device includes a processor and a non-transitory memory storing instructions that, when executed, cause the processor to operate in an open loop mode a motor that includes a rotor and a stator. An angle error of the rotor is determined. In response to the angle error of the rotor being less than a threshold, the processor transitions from operating the motor in the open loop mode to operating the motor in a closed loop mode by changing from using a first coordinate system based on a command rotor position to using a second coordinate system based on an estimated rotor position to determine current vectors used to control the motor; and holding constant a current vector used to control the motor while performing the changing action. After performing the changing and holding actions, the processor operates the motor in the closed loop mode.