Abstract: In one embodiment, a method includes measuring between two consecutive electrical commutations of a brushless direct-current (BLDC) motor a current through the BLDC motor. One or more pulse-width-modulation (PWM)-configurable signals are driving the BLDC motor. The method includes determining a waveform of the current through the BLDC motor; if the waveform of the current through the BLDC motor comprises a first type, then increasing a duty cycle of each of one or more of the PWM-configurable signals driving the BLDC motor; and, if the waveform of the current through the BLDC motor comprises a second type, then decreasing a time interval between electrical communications of the BLDC motor.

Abstract: A brushless D.C. motor includes having a rotor and a plurality of stator windings that define a stator field when driven by a bridge circuit, where a microprocessor drives the bridge circuit using a pulse-width modulation logic. The brushless D.C. motor is driven by triggering a commutation of the stator field; voltage induced by rotating the rotor in a non-energized stator winding is monitored to determine whether the voltage reaches, exceeds or is below a threshold voltage. A delay time between triggering the commutation of the stator field and the voltage reaching, exceeding or being below the threshold voltage is determined; and using the determined delay time a triggering time point for a next commutation of the stator field.

Abstract: The invention relates to a method for determining a rotor position of a two-phase synchronous machine (1) comprising two strands (A, B), particularly for electronically commuting the synchronous machine (1). Said method has the following steps: —alternately actuating each of the strands in a first actuating time window with an actuating value of positive polarity and in a second actuating time window with an actuating value of negative polarity, wherein the first and the second actuating time window alternately follow each other; —applying an actuating value of 0 during a measuring time window which is provided within at least one of the actuating time windows of a strand (A, B); —applying a measuring pulse to the corresponding strand (A, B) within the measuring time window in order to measure the inductance of the corresponding strand (A, B) as an indication of the rotor position, said strand inductance being dependent on the rotor position.

Abstract: A method for operation of an internal permanent magnet motor having a rotor includes determining whether a neutral point access signal is received from the rotor and operating the internal permanent magnet motor using sensorless signals corresponding to a rotor position and a rotor speed derived by a first sensorless signal estimation method when the neutral point access signal is received, wherein the first sensorless signal estimation method utilizes the neutral point access signal to generate the rotor position and the rotor speed. The method further includes operating the internal permanent magnet motor using sensorless signals corresponding to a rotor position and a rotor speed derived by a second sensorless signal estimation method when the neutral point access signal is not received, wherein the second sensorless signal estimation method does not utilize the neutral point access signal to generate the rotor position and the rotor speed.

Abstract: In a system, a superimposing element sets a command value vector of a high-frequency voltage signal and superimposes the high-frequency voltage signal with the command value vector on an output voltage of an inverter. The high-frequency voltage signal has a frequency higher than an electrical angular frequency of a rotary machine. The command value vector is correlated with a measured high-frequency component value of a current signal flowing in the rotary machine. A calculating element calculates a rotational angle of the rotary machine based on the measured high-frequency component value of the current signal flowing in the rotary machine. A reducing element controls at least one of the inverter and a direct voltage power supply to reduce a difference due to the dead time between the command value vector and a vector of a high-frequency voltage signal to be actually superimposed on the output voltage of the inverter.

Abstract: A method of estimating inductance of a permanent magnet synchronous motor (PMSM) includes injecting a signal having a frequency differing from an operating frequency of the PMSM into the PMSM during sensorless operation, sensing magnitudes of current responses to the injected signal, and estimating an inductance value at which the magnitude of the sensed current response is minimal to be an actual inductance value of the PMSM, thereby estimating inductance used in the PMSM regardless of position estimation error of the PMSM and thus more accurately and reliably estimating inductance of the PMSM.

Abstract: A method and apparatus for determining electrical parameters for commissioning a sensor-less permanent magnet synchronous machine uses knowledge of the rotor position to apply balanced pulses along the rotor magnet axis and perpendicular to the rotor magnet axis allowing measurement of q- and d-inductance at multiple current levels without substantial rotor movement.

Abstract: Because there is a desire to migrate to sensorless, brushless direct current (DC) motors in large scale applications (i.e., vehicles), there is a need to provide a control system for such motors in large scale applications. Here, a motor controller is provided that uses small voltage pulses to generate currents (which are sufficiently small so as to not commute the motor) through pairs of phases. Based on the rise times of these currents, the motor controller can determine the initial position by using a lookup table (LUT) without commuting the motor.

Abstract: A motor controller for determining a position of a rotor of an AC motor, the motor controller comprises a control input for receiving a control signal, an output for providing a power control signal for controlling power applied to a stator of the AC motor, and an input for receiving a feedback signal representative of the current in the stator. The control input and output are coupled by a reference path, and the input is coupled to the control input by a feedback path. A carrier signal injection element injects a high frequency carrier signal in the reference path at an injection node. The motor controller is arranged to generate the power control signal in dependence on the control signal, the feedback signal, and the high frequency carrier signal. A position determining element generates a position signal representing the position of the rotor in dependence on the feedback signal which includes a carrier signal component comprising rotor position information.

Abstract: A robust method for detecting a relative position of a feedback device, such as an encoder or resolver, coupled to a shaft, such as a motor shaft, is provided. To detect the relative position, electrical commands are issued in an open loop mode to spin the motor shaft an amount greater than the apparent rotational angle between two consecutive markers of the position feedback device, such that the net mechanical rotation is equal to or greater than the total rotational angle between two consecutive markers.

Abstract: A method for determining the rotor position of a synchronous machine operated in field-oriented manner, which has an effective inductivity that is dependent on the rotor position, the motor current being acquired, and the motor voltage being set with the aid of a pulse-width-modulation method, a signal which is in synchrony with the pulse-width-modulation frequency being superimposed on the motor voltage value to be set, values of the motor current being acquired in synchrony with the pulse-width modulation frequency, a current component induced by the superimposed voltage signal and a residual current component, i.e., fundamental wave component, being determined, the current component induced by the superimposed voltage signal being used for determining an estimated rotor angle position, whose phase error in relation to the actual rotor angle position is reduced by means of a flux model, the residual current component being supplied to a current controller.

Abstract: A motor speed controller and a method of controller a speed of a motor are provided. The system and method include a motor and a motor controller that monitors operation of the motor based on electromotive force (EMF) conditions of the motor. The motor controller cuts a voltage to the motor, measures an electromotive force (EMF) of the motor at a predetermined time after the cutting of the voltage to the motor, and compares the measured electromotive force (EMF) to a table.

Abstract: A control device has a unit for preparing a pattern having first and second periods by comparing a triangular wave and a sine wave having an amplitude ratio set at each value of a modulation factor, and selecting one pattern corresponding to an instructed modulation factor, and a unit for applying a controlled voltage, set at low and high levels in response to first and second periods of the selected pattern, to a generator. The triangular wave has a cycle duration obtained by dividing the cycle duration of the generator by product of 3 and odd number, a crest having a level higher than the sine wave at a timing of each first period, and a trough having a level lower than the sine wave at a timing of each second period.

Abstract: A hybrid drive device includes a first motor; an operative mechanism that drivingly connects the first motor to an engine of a vehicle; a second motor that is drivingly connected to a drive wheel; an engine rotation speed sensor that detects a rotation speed of the engine; a magnetic pole position sensor that detects a magnetic pole position of the second motor; a current sensor that detects a current flowing to the first motor; a sensorless motor control device that estimates a magnetic pole position of the first motor based on the current detected by the current sensor, and drivingly controls the first motor; and a second motor control device that drivingly controls the second motor based on the magnetic pole position detected by the magnetic pole position sensor.

Abstract: An apparatus detects the position of a rotor of an electric motor having three phases and a plurality of windings. The apparatus includes circuitry configured to connect at least two of said windings between first and second reference voltages according to a first current path disconnect said at least two windings, and allow the current stored in said two windings to be discharged through a second current path. The apparatus comprises a measuring circuit configured to measure the time period between the starting instant of storing the current in the two windings and the final instant of discharging the two windings and a rotor detector configured to detect the rotor position based at least in part on the measured time period.

Abstract: A system includes a power control module, a period determination module, and a control module. The power control module controls current through stator coils of a motor to rotate a rotor. The period determination module determines a first length of time between a first set of induced stator coil voltages and determines a second length of time between a second set of induced stator coil voltages. The control module determines whether an external disturbance disturbs rotation of the rotor based on a difference between the first and second lengths of time.

Abstract: An apparatus for starting a direct current brushless motor and a method thereof are provided. The direct current brushless motor comprises a plurality of windings. The control apparatus comprises a sense amplifier, a differential circuit, and a control circuit. The sense amplifier is configured to detect a first back electro-motive force of a non-electrified first winding. The differential circuit is configured to calculate a differential value of the first back electro-motive force. The control circuit is configured to provide a current to two of the windings and to switch the current to another two of the windings to start the direct current brushless motor.

Abstract: A method for estimating a rotor position in an electrical machine is provided. The method is applicable to electrical machines that have magnetic saliency. The method includes extracting the rotor position from a demodulated output signal generated in response to an injected high frequency carrier signal and determining a position error compensation based upon a demodulation delay and a velocity or rotational frequency of the electrical machine. The method also includes estimating the rotor position by applying the position error compensation to the extracted rotor position.

Abstract: To estimate an initial magnetic pole position, estimated control axes corresponding to the d-axis and q-axis are set as the ?-axis and ?-axis, and a with high frequency rotation voltage or alternating voltage on the ?? coordinate system applied to the motor. A high frequency current ih flowing in the motor is then extracted from a detected motor current (armature current) and a direct current component (ih?×ih?)DC of a product of the ?-axis and ?-axis components of the high frequency current ih is derived. Alternatively, the ??-axis component ich? and the ??-axis component 66 of the high frequency current ih that are shifted by ?/4 in electric angle from the ?-axis and the ?-axis are used to obtain a direct current component of their product (ich?×ich?)DC. The magnetic pole position is then estimated by computing the axial error ?? between the ?-d axes utilizing the direct current components.

Abstract: A method of operating a WFSM in a motoring mode determines a relative position of a PMG rotor with respect to the WFSM rotor. A PMG is coupled to the WFSM via a coupling shaft. A relative difference between the WFSM rotor position and the PMG rotor position is determined based on carrier injection sensorless (“CIS”) stimulation signals. The relative difference between the PMG rotor and the WFSM main machine in conjunction with the PMG rotor position is used to determine the WFSM rotor position during motoring operation of the main machine. A stator of the WFSM main machine is energized to maintain operation of the WFSM in response to the detected main rotor position.

Abstract: A permanent magnet motor for position sensorless drive operation provides a stator design that exhibits a saliency (machine asymmetric) functionally dependent on rotor position as caused by periodic magnetic saturation of stator structure. This saturation property is caused by rotor zigzag leakage flux from surface permanent magnets. The stator structure may be designed to further saturate from zigzag leakage flux to provide greatest spatial saliency in the quadrature phase for motor position sensorless position estimation. The position, velocity, and shaft torque can be extracted by measuring the phase current from the stator coil of permanent magnet motor.

Abstract: Identification of electrical equivalent circuit parameters (15) of a three-phase asynchronous motor (09) without a shaft encoder. The method comprises—Assumption of a standstill position of the rotor (11);—Equidirectional test signal infeed U1?, U1? in ? and ? in the stator axis direction of the asynchronous motor (09);—Measuring of a measuring signal I1?, I1? of the ? and ? axial direction of the asynchronous motor (09); and—Identification of equivalent circuit parameters of the asynchronous motor (09) on the basis of the test signal voltages U1?, U1? and of the measuring signal currents I1?, I1?; whereby the test signal feed allows the rotor (11) to remain torque-free. Determination of equivalent circuit parameters (15) of an asynchronous motor (09) as well relates to a motor control device (35), whereby the identified equivalent circuit parameters (15) can be used for the determination, optimization and monitoring of a motor control and for control of electrical drives.

Abstract: A brushless motor control system according to the present invention detects a rotor stop position when activating the brushless motor including a stator having coils of three phases U, V, and W, and controls a phase voltage for energizing the coils of the respective phases U, V, and W, and the brushless motor includes the stator having coils of phases U, V, and W of N (N?2) poles, in which any one phase coil among the coils of the phases U, V, and W is removed in one of the N poles, and the brushless motor control system includes: a current rise detecting circuit that, when the brushless motor is in a stop state, sequentially selects coils of two phases from the coils of the respective phases U, V, and W, applies a predetermined direct current voltage between the selected coils of the two phases, and detects a value of an electric current flowing to the selected coils of the two phases; and a rotor stop position detecting unit that determines a rotor stop position of the brushless motor based on information o

Abstract: A flux regulated permanent magnet brushless motor has a stator having an inner peripheral bore. A permanent magnet rotor is mounted within the inner peripheral bore. A control winding is supplied to a DC current to regulate flux of the machine. A small AC current is also supplied and an output is sensed to determine a position of the permanent magnet rotor.

Abstract: A system. The system includes a first module, a second module communicably connected to the first module, a third module communicably connected to the first module, and a fourth module communicably connected to the third module. The first module is configured for determining an angle. The angle is defined by a first rotating reference frame having an axis aligned with a permanent magnet flux of a permanent magnet motor, and a vector of a motor magnetizing flux of the permanent magnet motor. The second module is configured for defining a second rotating reference frame having an axis aligned with the vector, and for transforming a two-phase set of direct currents from the first rotating reference frame to the second rotating reference frame. The first and second rotating reference frames are synchronized. The third module is configured for generating a first direct current reference signal associated with the second rotating reference frame.

Abstract: In a synchronous machine starting device, an AC voltage detection unit detects AC voltage supplied to an armature of a synchronous machine through an electric power line from a power conversion unit. The AC voltage detection unit has a first output end and a second output end isolated from the electric power line, transforms AC voltage supplied through the electric power line at a first ratio to output the transformed voltage from the first output end, and transforms AC voltage supplied through the electric power line at a second ratio and then limits the transformed voltage to a prescribed positive voltage value or lower and a prescribed negative voltage value or higher for output from the second output end. Then, a detected voltage selection unit selects one of the voltage received from the first output end and the voltage received from the second output end, and outputs the selected one to a rotor position detection unit.

Abstract: The invention relates to a synchronous motor (12) with a number of stator coils (15), with a rotor (16) with at least one permanent magnet (17), which induces a rotor magnetic field in a useful flux direction and with at least one coil winding (20), which is fitted on the rotor in order to induce a resultant magnetic field as a result of an alternating magnetic fields which is applied with the aid of the stator coils, in the direction of a winding axis of the coil winding, so that a resultant inductance of the stator coils (15) with respect to a direction of the winding axis is different given different positions of the rotor (16).

Abstract: The invention relates to a method of controlling the run-up of an electronically commutated electric motor (1) to drive a tool. A rotor 7 rotates in the rotating field (21) of the stator (2). The field windings (3, 4, 5) alternately have a supply voltage applied thereto via an actuation unit (10) in order to obtain an advancing motor rotating field. For advancing the rotating field in the rotational direction (29) of the rotor (7), the inductance of the arrangement of the field coils (3, 4, 5), which is ascertained via a changing measuring current (IM), is evaluated and the advancement is carried out upon reaching a maximum.

Abstract: A motor control device includes a dq-axis current control unit for generating a dq-axis voltage reference based on a dq-axis current reference and a dq-axis current signal, an initial magnetic pole position estimation unit for estimating a magnetic pole position of the motor upon power-on to generate a magnetic pole position signal, and a magnetic pole position estimation precision confirming unit for supplying a current in a d-axis direction after generation of the magnetic pole position signal with the initial magnetic pole position estimation unit, and checking an error of the magnetic pole position signal based on an angle of movement of the motor.

Abstract: A synchronous-machine starting device includes an induction voltage operating unit (61) calculating an induction voltage induced to an armature of a synchronous machine based on an estimated phase representing a position of a rotor, an estimated rotational speed of a rotor, an AC voltage signal, and an AC current signal, and outputting an induction voltage signal representing the calculated induction voltage, a selection unit (SEL) selecting and outputting one of the induction voltage signal received from the induction voltage operating unit (61) and the AC voltage signal received from the AC voltage detection unit, and a feedback operating unit (34) calculating an error of the estimated phase based on the induction voltage signal or the AC voltage signal received from the selection unit (SEL), calculating the estimated phase and estimated rotational speed based on the calculated phase error, outputting a speed signal representing the calculated estimated rotational speed to the induction voltage operating un

Abstract: Determination of an estimated initial angular position of the rotor of an AC motor includes application of voltages corresponding to a high frequency reference signal vector to the stator windings of the motor and production of an estimated initial angular position of the rotor as a function of the resulting q-axis stator current component iq_HF, adjustment of transformation of signal vectors from stationary to rotating coordinates and vice versa using the estimated angular position, and production of an adjusted estimated angular position of the rotor as a function of the q-axis stator current component as adjusted.

Abstract: A shift-by-wire shift switching device and shift switching method that switch a shift range of an automatic transmission using an electric motor. The shift switching device includes a controller that determines whether a fault has occurred in a current supply line of each phase of the electric motor on a phase-by-phase basis, executes an open-loop control of the electric motor using only the phases in which it has been determined that a fault has not occurred, and determines whether a fault has occurred in the current supply line by detecting an activation state of the electric motor when the open-loop control of the electric motor is executed. Therefore, it is possible to determine whether a fault in the motor is a short-circuit fault or a break fault, without addition of a part such as a short-circuit detection sensor.

Abstract: A motor control device that has a high-frequency component, and a DC bias component that has a magnitude which causes a motor to be magnetically saturated and take on a certain value over a predetermined period, and is positively and negatively symmetrical are impressed as an observation command on a d-axis current command. The polarity of the magnetic pole of a permanent magnet is identified based on a relationship of large and small magnitudes between a first amplitude, which is attained during a period during which a DC bias component takes on a positive certain value, among amplitudes of a high- frequency component contained in a d-axis response voltage computed based on a feedback current respondent to the observation command, and a second amplitude attained during a period during which the DC bias component takes on a negative certain value.

Abstract: Methods and apparatus are provided for aligning a control reference axis with a magnetic north of a permanent magnet motor. The method includes the steps of injecting a predetermined stator current on an estimated reference axis of the permanent magnet motor and introducing predetermined error on the estimated reference axis. The method further includes the steps of determining if a speed of the permanent magnet motor is greater than a predetermined threshold speed and setting the control reference axis to 180° added to the estimated reference axis if the speed of the permanent magnet motor is greater than the predetermined threshold speed or setting the control reference axis to the estimated reference axis if the speed of the permanent magnet motor is less than or equal to the predetermined threshold speed.

Abstract: A motor controller for determining a position of a rotor of an AC motor, the motor controller comprises a control input for receiving a control signal, an output for providing a power control signal for controlling power applied to a stator of the AC motor, and an input for receiving a feedback signal representative of the current in the stator. The control input and output are coupled by a reference path, and the input is coupled to the control input by a feedback path. A carrier signal injection element injects a high frequency carrier signal in the reference path at an injection node. The motor controller is arranged to generate the power control signal in dependence on the control signal, the feedback signal, and the high frequency carrier signal. A position determining element generates a position signal representing the position of the rotor in dependence on the feedback signal which includes a carrier signal component comprising rotor position information.

Abstract: A synchronous machine starting device includes a power conversion unit for converting supplied power into AC power and supplying the AC power to an armature of a synchronous machine, an AC voltage detection unit for detecting AC voltage supplied to the armature of the synchronous machine, a rotor position detection unit for detecting a rotor position of the synchronous machine, based on the detected AC voltage, and a power conversion control unit for controlling the power conversion portion, based on the detected rotor position.

Abstract: When a driver unit is in a high impedance state as viewed from a first coil or a second coil, an induced voltage detector detects the voltage across the first coil or that across the second coil so as to detect an induced voltage occurring in the first coil or the second coil. The induced voltage detector includes a differential amplifier circuit for differentially amplifying an electric potential across the first coil or that across the second coil, and an analog-to-digital converter circuit for converting an analog value outputted from the differential amplifier circuit into a digital value and outputting the converted digital value to a control unit. The control unit generates a drive signal based on an input signal set externally and adjusts the drive signal in accordance with the induced voltage detected by the induced voltage detector so as to set the adjusted drive signal in the driver unit.

Abstract: A method and apparatus for determining rotor position in a stationary rotor of a sensor-less permanent magnet synchronous machine that employs a rotating magnetic field to identify a magnetic axis of the stator without a magnetic direction and then determines magnetic direction by applying pulses along the magnet axis in two polarities.

Abstract: A system and method for determining the start position of a motor. According to an embodiment, a voltage pulse signal may be generated across a pair of windings in a motor. A current response signal will be generated and based upon the position of the motor, the response signal will be greater in one pulse signal polarity as opposed to an opposite pulse signal polarity. The response signal may be compared for s specific duration of time or until a specific integration threshold has been reached. Further, the response signal may be converted into a digital signal such that a sigma-delta circuit may smooth out glitches more easily. In this manner, the position of the motor may be determined to within 60 electrical degrees during a startup.

Abstract: A method is provided for operation of an internal permanent magnet motor having a rotor. The method includes determining whether a neutral point access signal is received from the rotor and operating the internal permanent magnet motor using sensorless signals corresponding to a rotor position and a rotor speed of the rotor derived by a first sensorless signal estimation method when the neutral point access signal is received from the rotor, wherein the first sensorless signal estimation method utilizes the neutral point access signal to generate the rotor position and the rotor speed.

Abstract: Methods and apparatus are provided for startup of a permanent magnet alternating current (AC) motor. The method comprises the steps of detecting startup of the permanent magnet AC motor; detecting a mechanical oscillation of the permanent magnet AC motor when startup of the permanent magnet AC motor is detected; and, in response to detection of the mechanical oscillation of the permanent magnet AC motor when startup is detected, suppressing the mechanical oscillation of the permanent magnet AC motor.

Abstract: The invention relates to a frequency converter, and also to a method for determining the position of the rotor of an electric machine. The frequency converter comprises a load bridge and also a control of the load bridge, for supplying electricity between the load bridge and an electric machine connected to the load bridge. The frequency converter comprises a determination for at least one electrical parameter of the aforementioned electric machine, and the frequency converter comprises a determination for the position of the rotor of the aforementioned electric machine. The load bridge is fitted to supply a first alternating electricity excitation signal, which is formed in relation to the electrical angle of the electric machine, to the aforementioned electric machine.

Abstract: Methods, system and apparatus are provided for low speed sensorless rotor angular position estimation that implements reduced switching loss PWM waveforms.

Abstract: A controller (100) for controlling a salient-pole machine (200) is disclosed. The controller (100) is adapted to determine at least one operational parameter of the salient-pole machine (200), such as for example a rotor position, a rotor angle or a steady-state voltage. The controller (100) comprises a calculating unit for calculating test pulse properties for test pulses for supply to phase inputs of the salient-pole machine. The test pulse properties thereby comprise a pulse width and the calculating unit (110) is adapted for determining the pulse width in an adaptive manner.

Abstract: When starting a brushless motor, if the stop position of the rotor is detected between time t1 and time t2, a start-up excitation pattern in accordance with the rotor stop position is input for an initial energization time Ts1. Afterward, when the energization is stopped, a plurality of signals SL1, SL2, SL3, SL4 are generated in sequence in excitation switch timing signals in accordance with the rotational position of the coasting rotor. From these signals SL1 to SL4, the rotor position is detected using the second and subsequent signals SL2 to SL4 and then the process shifts to ordinary energization switch control. In accordance with the present invention, it is possible to start up a motor in a short time with a simple method so as to obtain a large torque during start-up.

Abstract: A method for estimating a rotor position in an electrical machine is provided. The method is applicable to electrical machines that have magnetic saliency. The method includes extracting the rotor position from a demodulated output signal generated in response to an injected high frequency carrier signal and determining a position error compensation based upon a demodulation delay and a velocity or rotational frequency of the electrical machine. The method also includes estimating the rotor position by applying the position error compensation to the extracted rotor position.

Abstract: Provided is a method of indirect position estimation in three-phase switched reluctance machines. The method may comprise providing a three-phase switched reluctance machine. A three-phase switched reluctance machine may comprise a rotor and three phases. The method may further comprise producing data about the machine, setting threshold current values for at least a first phase; and sensing rotor position. Sensing rotor position may comprise applying a sensing pulse voltage sufficient to induce a pulse current having some maximum amperage in the first phase, determining the amplitude of the maximum amperage of said pulse current with respect to the thresholds for the first phase, and determining the sector of the rotor based upon the amplitude of the maximum amperage of the pulse current in the first phase.

Abstract: An apparatus and method for providing improved sensorless control of permanent magnet motors is described. Induced electricity from at least one winding set is used to determine rotor position and provide feedback to a commutation circuit driving at least another winding set isolated from the first.

Abstract: A method for determining the position of a rotor in a permanent magnet synchronous motor includes applying voltage pulses to the windings at successive electrical angles while the motor is at a standstill. The resultant current is sampled. The position of a maximum current is determined by identifying an segment of an electrical cycles which includes the maximum current, and using a spline interpolation to model the current flow in this segment. The maximum current is then correlated to the position of the rotor.

Abstract: An apparatus and method for use with a PMSM detect the fall time or the rise time and the fall time of a motor current in the PMSM under different voltage vectors when the PMSM is in start-up to determine an initial rotor position for the PMSM at standstill.