A motor system can include a motor, the motor including at least a rotor, and a controller configured to operate the motor. The controller can be configured to perform operations for operating the motor. The operations can include determining an initial estimated rotor angle, determining one or more estimated currents defined by an estimated rotating reference frame based at least in part on the estimated rotor angle, obtaining one or more current measurements of one or more measured currents respective to the one or more estimated currents, determining one or more current errors based at least in part on a subtractive combination of the one or more estimated currents and the one or more measured currents, determining one or more rotor flux estimates based at least in part on the one or more current errors, the one or more rotor flux estimates comprising at least an estimated δ-directed rotor flux vector, and determining an estimated rotor speed based at least in part on an integral of the estimated δ-directed rotor flux vector.

According to embodiments described herein, there are provided methods and apparatus for providing a driving signal to a transducer, wherein the driving signal is output by an amplifier. A method comprises receiving an indication of a voltage and a current of the driving signal; based on an electrical model of the transducer and the voltage and the current of the driving signal, estimating an estimated electrical response of the transducer representative of movement of a mass in the transducer; comparing the estimated electrical response to a desired electrical response; and controlling the driving signal based on the comparison.

A power tool is provided including a housing, a brushless motor disposed within the housing, a power switch circuit that supplies power from a power source to the brushless motor, and a controller configured to apply a drive signal to the power switch circuit to control the supply of power to the brushless motor. The controller is configured to receive at least one signal associated with a phase current of the motor, detect an angular position of the rotor based on the phase current of the motor within a variable speed range of zero to at least 15,000 rotations-per-minute (RPM), and control the drive signal based on the detected angular position of the rotor to electronically commutate the motor within a torque range of zero to at least 15 newton-meters (N.m.) and a power output of zero to at least 1500 watts.

A power tool is provided including a housing, a brushless motor disposed within the housing, a power switch circuit that supplies power from a power source to the brushless motor, and a controller configured to receive at least one signal associated with a phase current of the motor, detect an angular position of the rotor based on the phase current of the motor, and apply a drive signal to the power switch circuit to control a commutation of the motor based on the detected angular position of the rotor. The controller detects an initial sector within which the rotor is located at start-up, apply the drive signal so as to rotate the motor to a parking angle associated with the detected initial sector, and control a commutation sequence to drive the motor beginning at the parking angle.

A power tool is provided including a housing, a brushless motor disposed within the housing, a power switch circuit that supplies power from a power source to the brushless motor, and a controller configured to receive at least one signal associated with a phase current of the motor, detect an angular position of the rotor based on the phase current of the motor, and apply a drive signal to the power switch circuit to control a commutation of the motor based on the detected angular position of the rotor. If the supply of power to the motor is turned OFF to cause the motor to slow down and is turned back ON while the rotor speed exceeds a speed threshold, the controller electronically brakes the motor for a time interval to measure the phase current of the motor and detects the angular position of the rotor based on the measured phase current.

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.

According to embodiments described herein, there is provided methods and apparatus for providing a driving signal to a transducer, wherein the driving signal is output by an amplifier. A method comprises receiving an indication of a voltage and a current of the driving signal; based on an electrical model of the transducer and the voltage and the current of the driving signal, estimating an estimated electrical response of the transducer representative of movement of a mass in the transducer; comparing the estimated electrical response to a desired electrical response; and controlling the driving signal based on the comparison.

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 finite time speed control method for a permanent magnet synchronous motor (PMSM) based on a fast integral terminal sliding mode and disturbance estimation comprises: firstly, determining a mathematical model of a speed loop of the PMSM under the influence of system parameters uncertainty and unknown load torque; secondly, designing an improved fast integral terminal sliding surface on the basis of the idea of terminal sliding mode control; then, proposing a disturbance estimation method based on an adaptive fuzzy system with respect to the disturbance in a PMSM system; designing a PMSM speed controller on this basis; and finally, completing the concrete implementation of the whole technical solution. The present invention designs the fast integral terminal sliding surface and a sliding mode control law to ensure that a motor speed tracking error converges to zero within finite time and enhances the rapidity of a PMSM speed regulating system.

At least one example embodiment discloses a method of estimating a position of a rotor in a motor. The method includes determining a first estimated position of the rotor using a first algorithm, determining a second estimated position of the rotor using a second algorithm, the second algorithm being different than the first algorithm, determining a first error based on the first estimated position and the second estimated position, and determining a third estimated position of the rotor based on the first error.