Abstract: A motor controller is operable to control a motor. The motor has a first terminal and the motor controller includes an angular velocity transmission path having an input and an output. A current generator includes a velocity-torque input, an angular position input, and a motor drive output. The velocity-torque input is coupled to the output of the angular velocity transmission path. An angular velocity feedback path is coupled between a first terminal and a first location on the angular velocity transmission path. The first location is between the input and the output of the angular velocity transmission path. A current feedback path is coupled between the first terminal and a second location on the angular velocity transmission path. The second location is disposed between the first location on the angular velocity transmission path and the velocity-torque input of the current generator.

Abstract: Example systems and processes use three-phase vector mutual inductance analysis to detect zero-crossing (ZC) locations of back-electromotive force (BEMF) of an electric motor and to detect its commutation points during start-up or low-speed operation. For each sector of rotation of the rotor, two pairs of three-phase vectors are applied, along with current for the corresponding driving phase. The first pair is alternately applied to move the rotor, and the mutual inductances resulting from such application are compared to detect the zero-crossing (ZC) location in the BEMF of the electric motor in that sector. The second pair is then alternately applied within the same sector to continue to move the rotor, and the mutual inductances from such application are compared to detect the commutation point of the electric motor in that sector. The process may be repeated for each successive sector, changing the driving current at each new sector.

Abstract: Example systems and processes use three-phase vector mutual inductance analysis to detect zero-crossing (ZC) locations of back-electromotive force (BEMF) of an electric motor and to detect its commutation points during start-up or low-speed operation. For each sector of rotation of the rotor, two pairs of three-phase vectors are applied, along with current for the corresponding driving phase. The first pair is alternately applied to move the rotor, and the mutual inductances resulting from such application are compared to detect the zero-crossing (ZC) location in the BEMF of the electric motor in that sector. The second pair is then alternately applied within the same sector to continue to move the rotor, and the mutual inductances from such application are compared to detect the commutation point of the electric motor in that sector. The process may be repeated for each successive sector, changing the driving current at each new sector.

Abstract: A motor controller integrated circuit (IC) includes a storage device containing software, and a processor core. The processor core has an output adapted to be coupled to a motor. The processor core is configured to execute the software to operate the motor in an open-loop control, calculate first and second orthogonal components of a back electromotive force (BEMF), calculate a total BEMF value, and determine that the first orthogonal component is within a threshold of the total BEMF value. The processor core is further configured to, responsive to the first orthogonal component being within the threshold of the total BEMF value, operate the motor in a closed-loop control.

Abstract: A controller is adapted to be coupled to a brushless direct current (DC) motor and includes an analog-to-digital converter (ADC), a computing device, and a driver. The ADC is configured to receive an analog back electromotive force (BEMF) waveform from the brushless DC motor and sample the analog BEMF waveform to produce a digital BEMF waveform. The computing device is coupled to the ADC and is configured to receive the digital BEMF waveform and determine a position and a speed of the rotor based on the digital BEMF waveform. The driver is coupled to the ADC and the computing device and is configured to receive the position and the speed of the rotor and provide a drive signal based on the position and the speed of the rotor of the brushless DC motor.

Abstract: Described examples include a method that includes setting a reference iq signal in a field-oriented control of a motor such that the field-oriented control modulates power from a power supply using a modulator to apply a torque on the motor that is opposite to a kinetic energy applied to the motor. The method also includes setting a reference id signal in the field-oriented control such that the motor current provided to the power supply is reduced.

Abstract: Described examples include a method that includes setting a reference iq signal in a field-oriented control of a motor such that the field-oriented control modulates power from a power supply using a modulator to apply a torque on the motor that is opposite to a kinetic energy applied to the motor. The method also includes setting a reference id signal in the field-oriented control such that the motor current provided to the power supply is reduced.

Abstract: A controller is adapted to be coupled to a brushless direct current (DC) motor and includes an analog-to-digital converter (ADC), a computing device, and a driver. The ADC is configured to receive an analog back electromotive force (BEMF) waveform from the brushless DC motor and sample the analog BEMF waveform to produce a digital BEMF waveform. The computing device is coupled to the ADC and is configured to receive the digital BEMF waveform and determine a position and a speed of the rotor based on the digital BEMF waveform. The driver is coupled to the ADC and the computing device and is configured to receive the position and the speed of the rotor and provide a drive signal based on the position and the speed of the rotor of the brushless DC motor.

Abstract: Example systems and processes compare sampled values of a floating phase voltage and/or outgoing phase current of an electric motor with a corresponding reference to identify a degauss time period. Post degauss time period identification, sampled values are compared with a threshold to identify a settling time period following the degauss time period. The threshold used to identify the settling time period depends on a slope of a floating phase voltage after the degauss time period, a modulation scheme being used, and a pulse width modulation ON/OFF state of the electric motor. When the threshold comparison test is not met, it is determined whether the slope of the floating phase voltage has inverted. Based on such processing, a back-electromotive force (BEMF) zero-crossing (ZC) is detected or estimated with respect to a floating phase voltage of the electric motor.

Abstract: Described examples include a method that includes setting a reference iq signal in a field-oriented control of a motor such that the field-oriented control modulates power from a power supply using a modulator to apply a torque on the motor that is opposite to a kinetic energy applied to the motor. The method also includes setting a reference id signal in the field-oriented control such that the motor current provided to the power supply is reduced.

Abstract: A method for determining a position of a rotor of a brushless direct current (BLDC) motor at standstill. The method includes providing a plurality of current pulses to a plurality of windings of the BLDC motor while the rotor of the BLDC motor is at a standstill position. The method further includes measuring a plurality of times that it takes for the plurality of current pulses to reach a threshold for respective ones of the plurality of windings. A first position corresponding to a shortest time of the plurality of times is determined. A position detection value is determined based on the shortest time and based on times corresponding to positions that are adjacent to the first position. A position of the rotor at the standstill position is determined based on the position detection value and an interpolation function.

Abstract: A motor controller integrated circuit (IC) includes a storage device containing software, and a processor core. The processor core has an output adapted to be coupled to a motor. The processor core is configured to execute the software to operate the motor in an open-loop control, calculate first and second orthogonal components of a back electromotive force (BEMF), calculate a total BEMF value, and determine that the first orthogonal component is within a threshold of the total BEMF value. The processor core is further configured to, responsive to the first orthogonal component being within the threshold of the total BEMF value, operate the motor in a closed-loop control.

Abstract: A motor controller is operable to control a motor. The motor has a first terminal and the motor controller includes an angular velocity transmission path having an input and an output. A current generator includes a velocity-torque input, an angular position input, and a motor drive output. The velocity-torque input is coupled to the output of the angular velocity transmission path. An angular velocity feedback path is coupled between a first terminal and a first location on the angular velocity transmission path. The first location is between the input and the output of the angular velocity transmission path. A current feedback path is coupled between the first terminal and a second location on the angular velocity transmission path. The second location is disposed between the first location on the angular velocity transmission path and the velocity-torque input of the current generator.

Abstract: A motor control system operable to control a motor includes a motor control circuit and an inverter circuit connected to the motor control circuit and configured to connect to the motor at phase output terminals. The inverter circuit, in response to one or more output control signals indicating a deceleration instruction from the motor control circuit, implements a multi-state deceleration sequence for at least one commutation state of a commutation scheme of the motor.

Abstract: Example systems and processes control transition of an electric motor from open-loop operation to closed-loop operation by detecting zero-crossing (ZC) locations of the back-electromotive force (BEMF). The rotor angle of the electric motor is changed, e.g., by changing acceleration of the electric motor to correct a phase difference based on the detected ZC locations and an open-loop profile of the electric motor. Detected ZC locations may be used to identify ZC-detected-based commutation points, and each detected ZC location may be used to update a next commutation point. During the control process the open-loop profile is updated. Transition may occur when a set number of ZC-detection-based commutation points are sufficiently aligned with corresponding updated commutation points, or such alignment is maintained for at least one electrical cycle.

Abstract: A system includes: a motor having a stator and a rotor; and a pulse generation circuit coupled to the stator. The system also includes a motor controller coupled to the pulse generation circuit. The motor controller is configured to: determine inductance and resistance values of the motor based on timing parameters obtained during an initial position detection (IPD) interval; determine a rotor position based on the determined inductance and resistance values; and generate control signals for the pulse generation circuit based on the determined rotor position.

Abstract: A system includes: a motor having a stator and a rotor; and a pulse generation circuit coupled to the stator. The system also includes a motor controller coupled to the pulse generation circuit. The motor controller is configured to: determine inductance and resistance values of the motor based on timing parameters obtained during an initial position detection (IPD) interval; determine a rotor position based on the determined inductance and resistance values; and generate control signals for the pulse generation circuit based on the determined rotor position.