In sensorless control for a rotary machine, when variations in inductances for U, V, W phases due to manufacturing error are great, imbalance occurs among detected currents for the respective phases. Thus, estimation error of a magnetic pole position of a rotor increases, so that positioning accuracy is reduced. Correction filters for imparting gains in accordance with rotary machine constants for the respective phases are provided to control means or magnetic pole position calculation means, thereby correcting the imbalance occurring among the detected currents for the respective phases.

A method and device estimate an amplitude of a periodic component in a measured analog signal, e.g. from an electric motor, and adapt a control law for an external entity, e.g., a variable speed drive (VSD) controlling the motor, based on the estimated amplitude. The measured analog signal is converted by delta-sigma modulation to a digital signal that is applied to at least one filter. Periodic signals of independent known periodic functions are also applied to the at least one filter. In response, the at least one filter provides the estimated amplitude of the periodic component in the measured analog signal that may be used to adapt the control law. A monitoring value for the electric motor may also be based on the estimated amplitude of the periodic component.

According to an aspect, there is provided an apparatus for performing angular position error estimation. The apparatus operates (601) a synchronous motor (111) according to a pre-defined pulsating torque signal using a sensorless vector control method with high-frequency voltage injection. The pre-defined pulsating torque signal has a zero mean and corresponds to a torque operating point. The apparatus measures (602) a first value of an estimated angular position at a first time instance corresponding substantially to an end point of the pre-defined pulsating torque signal and second values of the estimated angular position and an estimated angular speed at a second time instance occurring after the first time instance. Based on the measured values, the apparatus estimates (603) an error in the estimated angular position and stores (604) the error to a lookup table. After performing said steps for one or more pre-defined pulsating torque signals, the apparatus operates (607) the synchronous motor (111) using the lookup table for angular position error correction.

A pole direction detection device for detecting a pole direction of a synchronous motor having saliency comprises a high-frequency voltage application unit that applies a high-frequency voltage to the motor; an excitation phase change unit that changes an excitation phase of the motor to an arbitrary phase; a driving current detection unit that detects a driving current value of the motor; a pole direction estimation unit that detects a pole direction based on the excitation phase and the driving current value; a measurement unit that measures an inductance value of the motor; and a control unit that changes a frequency of the high-frequency voltage to be applied by the high-frequency voltage application unit based on the inductance value measured by the measurement unit.

The disclosure relates to a method for determining a rotor position of an electric rotating machine. The electric machine comprises at least one first, multi-phase subsystem and one second multi-phase subsystem, which each comprise a PWM-controlled inverter for feeding respective winding groups. The winding groups of the at least first and second subsystems are arranged substantially electrically offset from one another by 360°. In the method, voltages predefined by a controller are altered by feeding high-frequency voltages in order to attain high-frequency current changes. The current changes are then detected in that a current curve of phase currents is ascertained for each subsystem by measuring at least one first phase current and one second phase current. The rotor position is then determined depending on the ascertained current curves and the fed high-frequency voltages. The disclosure additionally relates to an electric machine which is designed for carrying out the method.

An electrical rotating machine includes a machine housing accommodating a rotor, and a stator. In order to allow the method to be carried out without structural changes to the electrical rotating machine a first physical value of the stator and a second physical value of the rotor are measured outside the machine housing, and a state variable of the electrical rotating machine is determined from the first physical value and the second physical value. The state variable, or alternatively the first and second physical value, are sent to a cloud, in particular wirelessly or by hardwired or optical means.

Disclosed is a motor control apparatus, a motor control system, and a motor control method that estimate a stator resistance and a rotor position for sensorless control of a motor.

In sensorless control for a rotary machine, when variations in inductances for U, V, W phases due to manufacturing error are great, imbalance occurs among detected currents for the respective phases. Thus, estimation error of a magnetic pole position of a rotor increases, so that positioning accuracy is reduced. Correction filters for imparting gains in accordance with rotary machine constants for the respective phases are provided to control means or magnetic pole position calculation means, thereby correcting the imbalance occurring among the detected currents for the respective phases.

A method and a control apparatus for determining parameters for controlling an electric drive having an electric machine improve the start-up of the electric drive by applying a current indicator as a signal at three-phase winding connections of the electric machine, and measuring a d-component and a q-component of the stator voltage and of the stator current at the winding connections. In a first measurement step, a rotating current indicator is applied to the three-phase winding connections and the electric machine is oriented such that an exciter current in the q-axis assumes a minimum. In a second measurement step, when the rotor of the electric machine is stationary, a field winding of the electrical machine is short-circuited and a current indicator in form of a binary noise signal is applied to the winding connections. A stator impedance is then determined as a first control parameter.

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.