A circuit for controlling a motor that includes control circuitry configured to determine whether a commutation event has occurred for a first sector of a plurality of sectors of a cycle for the motor based on a first selected phase current signal and a second selected phase current signal. In response to a determination that the commutation event has occurred for the first sector, the control circuitry is configured to determine that the motor is operating in a second sector of the plurality of sectors of the cycle for the motor. The control circuitry is further configured to determine a second angle of stator voltage vector for the motor based on the determination that the motor is operating in the second sector and generate the control signal based on the second angle of stator voltage vector for the motor.

The present invention concerns a method and a device for determining a position of a rotor of a three-phase motor using a FOC system. The invention: —determines, by a proportional-integral controller, a first control voltage vector at a first instant, —transforms the first control voltage vector using an inverse Park transform, —sums the transformed first control voltage vector to a regular polygonal voltage pattern applied during a given duration, —performs a PWM from the sum of the transformed first control voltage vector and the regular polygonal voltage pattern, —controls the motor with the pulse-width modulation, —measures the current at each phase of the motor, —estimates the position of the rotor from the measured currents and from the regular polygonal voltage pattern, —determines, at a second instant, a second control voltage vector from the measured currents and from the estimated position.

Described is a method of determining an initial rotor position on start-up of a synchronous motor. The method comprises applying at each of a plurality of pre-set motor angles a pair of voltage vector pulses, the pair of voltage vector pulses comprising a first and second pulses, each having the same amplitude but opposite polarities, the second pulse being applied immediately or near immediately after the first pulse. The method includes determining the stator current responses to said pairs of applied voltage vector pulses at said plurality of pre-set motor angles. Then, the initial rotor position can be determined from either of a stator angle corresponding to a pair of vector voltage pulses resulting in (a) a largest sum of stator currents or (b) where the sum of stator currents changes from a negative to a positive motor angle.

Described is a method of determining an initial rotor position on start-up of a synchronous motor. The method comprises applying at each of a plurality of pre-set motor angles a pair of voltage vector pulses, the pair of voltage vector pulses comprising a first and second pulses, each having the same amplitude but opposite polarities, the second pulse being applied immediately or near immediately after the first pulse. The method includes determining the stator current responses to said pairs of applied voltage vector pulses at said plurality of pre-set motor angles. Then, the initial rotor position can be determined from either of a stator angle corresponding to a pair of vector voltage pulses resulting in (a) a largest sum of stator currents or (b) where the sum of stator currents changes from a negative to a positive motor angle.

Described is a method of aligning a rotor of a polyphase synchronous motor having a permanent magnet rotor to a predetermined, selected, or specified rotor angle. The method comprises sensing or measuring the stator winding voltages/currents during synchronous operation of the motor. Based on the sensed or measured stator winding voltages/currents, a synchronously rotating reference frame vector voltage (V.sub.9) in the q-axis is determined as a product of stator winding resistance (R.sub.s) and stator winding current (i.sub.q) in the q-axis. Corresponding polyphase drive voltages for the synchronous motor for the predetermined, selected, or specified rotor angle (θ) are determined from the synchronously rotating reference frame vector voltage (V.sub.q). The polyphase drive voltages are applied to align the rotor on stopping at said predetermined, selected, or specified rotor angle (θ), The polyphase drive voltages are applied by suitable PWM drive signals.

A method for initial position detection of an electric motor includes determining a delta voltage for each of three pairs of stator windings by sequentially energizing and deenergizing each pair. The delta voltage is measured through a non-energized stator winding connected to a center tap of each respective pair. A minimum delta voltage is determined from an absolute value of a minimum of the three delta voltages. The minimum delta voltage is associated with a remaining stator winding not included in the respective pair. The two delta voltages not associated with the minimum delta voltage are compared to determine the proximity of the remaining stator winding to one of a D-axis of a rotor of the electric motor and a Q-axis of the rotor.

A motor control device and a motor control method are provided. The motor control device includes a memory and a controller. During an initialization period, the controller drives a brushless DC motor to change a rotor position through a drive circuit for adjusting and obtaining a starting angle and a locked exciting current corresponding to the starting angle, and the controller stores starting-angle information corresponding to the starting angle and locked exciting-current information corresponding to the locked exciting current in the memory. After the initialization period ends, during a normal rotation period, the controller maintains the rotor position of the brushless DC motor at the starting angle with the locked exciting current through the drive circuit, until the controller activates the brushless DC motor through the drive circuit.

A motor control device and a motor control method are provided. The motor control device includes a memory and a controller. During an initialization period, the controller drives a brushless DC motor to change a rotor position through a drive circuit for adjusting and obtaining a starting angle and a locked exciting current corresponding to the starting angle, and the controller stores starting-angle information corresponding to the starting angle and locked exciting-current information corresponding to the locked exciting current in the memory. After the initialization period ends, during a normal rotation period, the controller maintains the rotor position of the brushless DC motor at the starting angle with the locked exciting current through the drive circuit, until the controller activates the brushless DC motor through the drive circuit.

A motor drive circuit provides a drive signal to an electronically commutated motor. A control circuit the motor drive circuit based on calibration data. The calibration data indicate a relationship between an actual angular position of a rotor of the motor in response to the drive signal and an expected angular position of a rotor of an ideal motor in response to the drive signal.

A method for detecting an initial position of a rotor of a permanent magnet synchronous motor in a no-load environment can comprise the steps of: estimating a temporary initial position α′ by means of aligning a d axis; measuring a first voltage command which is output by performing velocity control within predetermined velocity ranges with respect to the forward direction of a motor on the basis of the temporary initial position α′; measuring a second voltage command which is output by performing velocity control within the predetermined velocity range with respect to the reverse direction of the motor on the basis of the temporary initial position α′; calculating respective variations of the first voltage command and second voltage command, and calculating a compensation angle α″; and calculating an initial position α of the rotor on the basis of the sum of the temporary initial position α′ and compensation angle α″.