38 results about "Permanent magnet synchronous machine" patented technology

The invention discloses a high-bandwidth current control method and system used for a permanent magnet synchronous motor, and relates to the technical field of high-bandwidth current control of the permanent magnet synchronous motor, and the method comprises the following steps: S1, a current sampling and updating step: carrying out the secondary sampling of the stator current of the permanent magnet synchronous motor in a pulse width modulation carrier period, and two times of pulse width modulation duty ratio updating are correspondingly carried out to form double-sampling double-updating time sequence control. Through an innovative double-sampling and double-updating time sequence control strategy, two times of current sampling and two times of duty ratio updating are executed in a PWM carrier wave period, the total delay of the system is greatly reduced from the level of a traditional method, and according to the control system theory, the current loop bandwidth and the system delay are in an inverse proportion relation, so that the current loop bandwidth and the system delay are effectively controlled. The significant reduction of the time delay directly brings the multiplied increase of the current loop bandwidth, and the improvement lays a solid foundation for the high dynamic response performance of the whole servo system, so that the system can respond to the instruction change with higher frequency.

The invention relates to a rotor (10) of an electric machine (11) designed as a permanent magnet synchronous machine, said rotor (10) comprising a rotor base body (16) having pocket-like recesses (17, 18) which are open radially to the outside and permanent magnets (19, 20) which are positioned in the recesses (17, 18), said rotor (10) comprising poles (12) which are arranged alternately adjacent to one another and form pole pairs when viewed in the circumferential direction, wherein at least one permanent magnet group comprises permanent magnets (19, 20) arranged in recesses (17, 18) positioned in a V-shape in the region of each pole (12), which permanent magnets diverge radially outward, and wherein the radially outer ends of the permanent magnets (19, 20) arranged in the recesses (17, 18) positioned in the V-shape have outer surfaces (23, 24) with chamfers (25, 26), the rotor base body (16) has a chamfer (27) which extends in a tangential direction to or parallel to the outer circumference of the rotor base body (16) at a respective circumferential position of a respective radially outer end of a respective permanent magnet (19, 20) which extends adjacent to the outer circumference of the rotor base body (16), and wherein the rotor base body (16) supports a hoop (27) on the outer circumference.

A flux-mnemonic permanent magnet synchronous machine (FMPMSM) includes: an annular stator having a winding; a rotor disposed concentric with the stator; and a power inverter for dispensing an excitation current and at least one current pulse. The rotor includes: at least two circumferentially magnetized adjustable permanent magnets, each permanent magnet having two poles normal to an air gap between the stator and rotor; and one or more flux adjusters adjacent to one or more magnet poles of the permanent magnets. A polarization ratio of magnetization of at least one of the permanent magnets is adjustable during operation of the FMPMSM by application of the at least one current pulse.

The invention relates to a method for controlling an electric machine, the method comprising the following steps: detecting a predetermined operating state of the electric machine while performing traction control of the electric machine; performing transition control and / or monitoring upon detection of the predetermined operating state in order to subsequently switch an active short circuit of the electric machine, comprising the following steps: generating steady-state target current values ​​to produce an active short circuit based on current input variables of the electric machine; performing rate limiting to limit the maximum rate of change of the target current values;Implementation of a feedforward control process in which the target current values ​​output by the rate limiter are converted into target voltage values, which contain at least one component from a time-dependent change in the magnetic flux of the electric machine, and output for controlling the electric machine; switching the active short circuit of the electric machine. Furthermore, the invention relates to a corresponding control device, a corresponding computer program and a corresponding storage medium.

The present invention relates to a rotor (1) of an electric machine (10), in particular a permanent magnet synchronous machine, with a rotor body (2) extending about a rotor axis (100), in particular a rotor lamination stack, which has several magnet pockets (3) for arranging magnets (5a, 5b), in particular permanent magnets, to form rotor poles (9), wherein at least one of the rotor poles (9) has a radially outer V-shaped magnet layer (12) comprising at least two V-shaped outer magnets (5b) and a radially inner V-shaped magnet layer (13) comprising at least two V-shaped inner magnets (5a), wherein in the respective rotor pole (9) at least one separate pole intermediate segment (6) is formed in the radial direction (200) between the outer magnet layer (12) and the inner magnet layer (13), which is formed from a soft magnetic material,in particular a laminated core or a soft magnetic compound component, wherein the respective rotor pole (9) comprises a pole center axis (9a) and two pole halves (9b) provided on both sides of the pole center axis (9a), characterized in that in the respective rotor pole (9) two separate pole intermediate segments (6) are provided between the outer magnet layer (12) and the inner magnet layer (13), which are arranged separately from each other in two pole halves (9b).

The application discloses a full-speed-range speed sensorless construction method of a bearingless permanent magnet synchronous motor, a high-frequency signal injection method module and an AGA-EKF detection method module are connected in parallel and then jointly connected in series at the front end of a rotating speed switching algorithm module to form a composite method rotating speed detection module, the composite method rotating speed detection module is connected in series into a control system of the bearingless permanent magnet synchronous motor to inject a high-frequency voltage signal; the rotating speed of the motor is detected by using the pulse array high-frequency signal injection method under zero speed and low speed conditions, and the rotating speed information is detected by using an extended Kalman filter method optimized by using a self-adaptive genetic algorithm under medium and high speed conditions; the pulse array high-frequency signal injection method and the rotating speed and detection composite method based on the extended Kalman filter optimized by using the genetic algorithm are adopted to complete the speed detection of the motor running in the full-speed range of zero speed, low speed and high speed, and realize the smooth switching of the motor from low speed to high speed and the stable suspension running of the motor in the full-speed range.

There is described a method of detecting a fault during low rotational speed operation, the fault relating to determination of a rotor angular position of a permanent magnet synchronous machine (111) having at least one set of multi-phase stator windings, the method comprising: checking consistency (1) of at least two independent rotor angular position determination methods, thereby using at least an encoder-based method and a high-frequency injection-based method; if at least one consistency check fails, a fault (13, 14) is indicated.

The invention discloses a sliding mode observation method and a sliding mode observation system for permanent magnet synchronous motor non-inductive control, which are used for improving numerical stability and observation precision of a discrete system and realizing permanent magnet synchronous motor non-inductive closed-loop control with good robustness and stability. The method comprises the following steps: discretizing a current state equation according to a sampling period to obtain an initial discrete sliding mode observation equation; determining a proportional adjustment coefficient k based on an inductance parameter and a sampling period of the motor, performing weighted adjustment on a voltage related item and a sliding-mode control quantity item in the initial discrete sliding-mode observation equation by using the proportional adjustment coefficient k, and constructing an improved sliding-mode observation equation; extended counter electromotive force is extracted based on the output of the sliding mode control law, wherein the contribution proportion of the high-frequency buffeting component output by the sliding mode control law in the extended counter electromotive force is weakened through a proportion adjustment coefficient; and inputting the extended back electromotive force into a phase-locked loop module to calculate the rotor position and the rotating speed of the motor so as to realize closed-loop control of the motor.

Vector control method for a synchronous machine, in particular a permanent magnet synchronous machine, in which Q-axis and D-axis setpoint currents (Iq, Id) are determined by respective assignments (5, 5A) that define a flux linkage torque (M&PSgr;) and a setpoint flux strength (&PSgr;Tgt_MTPL) with the Q-axis setpoint current and D-axis setpoint current, respectively.The D-axis target current (Iq, Id) is determined by linking the flux linkage torque (M) to a difference between a target torque (MTgt) and an iron loss torque (MIron), wherein the assignments (5, 5A) for determining the Q-axis target current (Iq) and the D-axis target current (Id) disregard a voltage variation of a voltage to be applied to the stator windings of the synchronous machine and the voltage variation is previously regulated or compensated by adjusting the target flux strength (Tgt_MTPL), characterized in that the voltage variation is regulated or compensated on the basis of a flux strength difference (Error) between a maximum flux strength (Max) and a current flux strength (ctrl_req).

The invention relates to a rotor (1) of an electric machine, in particular a permanent magnet synchronous machine, with a rotor shaft (2) and with laminated cores (3) arranged non-rotatably on the rotor shaft (2), in which permanent magnets (4) are integrated, wherein the laminated cores (3) are arranged side by side in the circumferential direction of the rotor shaft (2) and are connected to the rotor shaft (2) by positive and / or frictional engagement, wherein each of the laminated cores (3) consists of a radially inner lower pole body (5) and a radially outer upper pole body (6), between which the permanent magnets (4) are arranged, wherein each of the laminated cores (3) is provided with a winding with a winding element (7).

A stator for a synchronous motor and a synchronous motor. The invention relates to a stator or a stator segment for a synchronous machine, in particular a permanent magnet synchronous machine, comprising: a plurality of lamination stacks, each extending in a circumferential direction and a radial direction and each consisting of sheets stacked in an axial direction, the lamination stacks being arranged spaced apart in the axial direction, each lamination stack includes a yoke portion and a plurality of tooth portions protruding in a radial direction, a groove portion is formed between each pair of adjacent tooth portions, and the groove portions of the plurality of lamination stacks are aligned in a circumferential direction such that a plurality of grooves extending in an axial direction are formed, wherein a radially extending cooling fluid duct is formed axially between at least one pair, in particular each pair, of adjacent lamination stacks; the stator coils are arranged in a plurality of slots according to a centralized winding topology such that a first coil portion, in particular a first coil, and a second coil portion, in particular a second coil, are arranged in each slot.

Method for detecting a rotational position of a rotor of a permanent magnet synchronous machine (101), wherein • a first measurement signal (uc) designed as an alternating signal in rotor coordinates (d, q) is provided, transformed by a transformer control signal to the transformer stage (112) in stator coordinates (a, b) and fed into the permanent magnet synchronous machine (101), • the first measurement signal (uc), transformed in stator coordinates (a, b) and formed by a carrier voltage (uc), generates a second measurement signal (ic, ic1, ic2) as a reaction in at least one stator winding of the permanent magnet synchronous machine (101), designed as an alternating signal and formed by a carrier current (ic, ic1, ic2). • the second measurement signal (ic, ic1, ic2) is measured and back-transformed into the rotor coordinates (d, q) by the transformer control signal to the transformer stage (113), • an angle difference to the first measurement signal (uc) is obtained from the second measurement signal (ic, ic1, ic2) which has been transformed back into the rotor coordinates (d, q), • the transform control signal is formed from the angle difference by PI control and subsequent integration, and the transform control signal forms a measure of the rotational position of the rotor, • through the PI control, the angle difference is further regulated at least almost to zero, thereby achieving an alignment of the orientation of a real axis (d) of the rotor coordinates (d, q) with a rotor axis (118) along which a resultant permanent magnet flux of the rotor caused by permanent magnets encompassed by the rotor is aligned, • to determine the polarity of the permanent magnet flux with respect to the real axis (d) of the rotor coordinates (d, q), at least one operating point setting signal (ia, ua) is additively superimposed on the first measurement signal (uc). • a change in the amplitude of the second measurement signal (ic, ic1, ic2) is caused by at least one operating point setting signal (ia, ua) superimposed on the first measurement signal (uc) and • from the change in the amplitude of the second measurement signal (ic, ic1, ic2) or of the second measurement signal (ic, ic1, ic2) transformed back into the rotor coordinates (d, q) information about the polarity of the permanent magnet flux with respect to the real axis (d) of the rotor coordinates (d, q) is obtained by the fact that - a decrease in the amplitude of the second measurement signal (ic, ic1, ic2) with the same polarity and - an increase in the amplitude of the second measurement signal (ic, ic1, ic2) occurs with opposite polarity.

A method of changing a magnetic flux density in an air gap between a stator and a rotor in a real-time flux-mnemonic permanent magnet synchronous machine comprising permanent magnets, the method comprising applying at least one current pulse to adjust a magnetic operating point of the magnets, wherein the at least one current pulse has a duration of less than 3 ms. For applying the at least one current pulses, the method comprises consecutively applying a plurality of primitive pulses.

The present invention relates to a rotor (1) for an electric machine. The rotor (1) according to the invention is preferably used in a permanent magnet synchronous machine (PMSM). The rotor (10) has an inner lamination stack (10) and several outer lamination stacks (20) and several buried magnet assemblies (30) with at least one magnet (31, 32), wherein the inner lamination stack (10) has several recesses (11) distributed along a circumferential direction, the recesses being open radially outwards, wherein one of the several magnet assemblies (30) and one of the several outer lamination stacks (20) are arranged in each recess, wherein the at least one magnet (31, 32) of the respective magnet assembly (30) is arranged between the outer lamination stack (20) and the inner lamination stack (10).wherein the rotor (1) has a bandage (40) for fixing the multiple outer lamination stacks (20) and the multiple magnet arrangements (30) in the recesses of the inner lamination stack (10), wherein the bandage (40) radially surrounds the arrangement of inner lamination stack (10), magnet arrangements (30) and outer lamination stacks (20), wherein the inner lamination stack (10) has a retaining section (12) projecting into the recess in the region of the respective recess, wherein the retaining section (12) engages the at least one magnet (31, 32) of the magnet arrangement (30) arranged in the recess on a first side of the at least one magnet (31, 32) facing the outer lamination stack (20).

The utility model discloses a motor rotor and a permanent magnet synchronous motor. The motor rotor comprises a rotor iron core; the at least two stages of permanent magnets are arranged along the axial direction, and each stage of permanent magnet comprises a plurality of permanent magnets arranged on the circumferential outer side of the rotor core; the middle accommodating groove is positioned between two adjacent stages of permanent magnets in the at least two stages of permanent magnets; the injection molding body is filled in the rotor iron core and extends into the middle accommodating groove so as to fix the rotor iron core and the at least two stages of permanent magnets together; wherein a protection structure is arranged between two adjacent stages of permanent magnets, and the protection structure is configured as a film on the surface of the permanent magnet.

The invention relates to a rotor (16) for a permanent magnet synchronous machine (12) of a motor vehicle (10), with a rotor body having a plurality of recesses, wherein respective permanent magnets (18) are arranged in the recesses, wherein in a first region (20) of the rotor (16), for which a higher temperature development during operation of the rotor (16) is predicted, permanent magnets (18) with a higher concentration of heavy rare earth elements are arranged than in a second region (22) of the rotor (16), for which a comparatively lower temperature development is predicted.

The invention relates to an ultrahigh magnetic resistance topological rotor structure and a permanent magnet synchronous motor, the rotor structure comprises a rotor punching sheet, the rotor punching sheet is provided with an outer circle, a magnetic field regulation and control unit is arranged in the circumferential direction of the rotor punching sheet, and the magnetic field regulation and control unit is provided with a magnetic pole center line coinciding with the geometric center line of the rotor punching sheet; the magnetic field regulation and control unit is provided with N layers of magnetic steel groove structures which are arranged at intervals in a stepped manner; a first-layer magnetic steel groove is formed in the first layer, and the first-layer magnetic steel groove is provided with a first-layer magnetic steel area and a first-layer air area which are connected with each other; three i-layer magnetic steel grooves are arranged in each layer from the second layer to the Nth layer. According to the scheme, the torque density and the wide-range efficiency are remarkably improved, the flux-weakening speed expansion capability and the maximum operation rotating speed are greatly enhanced, the using amount of the permanent magnets is reduced, the material cost is effectively reduced, the peak current is greatly reduced, the converter capacity is reduced, and the system cost is reduced.

Method for field-oriented control of a synchronous machine, in particular a permanent magnet synchronous machine, of a vehicle in which additional losses (P loss_tgt ) in the synchronous machine for heating at least one further component of the vehicle with the resulting waste heat, characterized in that one of the additional losses (P loss_tgt ) corresponding loss current (I amp_tgt ) is calculated, a device for determining d-current (I d_tgt_LUT ) and q-current (I q_tgt_LUT) used target flow (ψ Max ) according to the loss current (I amp_tgt ) is reduced, the reduction of the target flow (ψ Max ) on one for a target torque (Trq tgt ) required minimum flow (ψ Min ) is limited and an excess flow (ψ corr_overflow ) when limiting the target flow (ψ Max ) is determined, and the d-current (Id_tgt_LUT ) and the q-current (I q_tgt_LUT) corresponding to the excess flow (ψ corr_overflow ) are corrected in such a way that the target torque (Trg tgt ) is issued.

The invention relates to a rotor (9) of an electric machine (1) having permanent magnets (14), comprising a magnetically conductive base body, in particular an axially layered laminated core (11), which base body is provided with the permanent magnets (14) at least in some regions circumferentially and / or axially in substantially axially extending recesses (13), one or more permanent magnets (14) forming poles (19), the invention relates to a rotor (9) comprising a plurality of permanent magnets (14), each of which has a pole that forms the north pole (N) or south pole (S) of the rotor (9) in the direction of the outer circumference (18), the magnetically conductive base body and the corresponding permanent magnet (14) each forming part of a closed magnetic circuit (22), and means are present in the magnetic circuit (22), said means being arranged magnetically in series in the magnetization direction of the permanent magnets (14) and protecting the permanent magnets (14) against overtemperatures and thus against irreversible demagnetization.

There is described a method of determining an electrical rotor position value (108) of a synchronous machine (1361), in particular a permanent magnet synchronous machine, having a stator (1362) with a stator winding, the method comprising: providing a plurality of candidate values (106) of the electrical rotor position; providing a plurality of stator winding current component values (103a) and a plurality of stator winding voltage component values (103b); calculating values of components (105a, b) of an estimated back EMF based on the plurality of candidate values (106), the plurality of current component values (103a), and the plurality of voltage component values (103b), in particular using a set of equations (equations (3, 4; providing (107) a cost function (g) as an actual value function of the components (105a, b) of the estimated back EMF, which cost function is ascertained as two different values if the error of the electrical rotor position value is zero or pi; evaluating the candidate value (106) using a cost function (g); a value (108) as an actual electrical rotor position value is defined based on the evaluation.

A method for estimating the resistance of stator windings of an electric machine used in a vehicle, in particular a permanent magnet synchronous machine that can be driven via a power output stage, is disclosed. Furthermore, a control unit configured and programmed to execute the method and an electric machine, in particular a permanent magnet synchronous machine, comprising the power output stage and the control unit, are disclosed.

The application discloses a sliding mode observation method and system for permanent magnet synchronous motor non-inductive control, which is used for improving the numerical stability and observation accuracy of a discrete system, and realizing the non-inductive closed-loop control of the permanent magnet synchronous motor with good robustness and stability. The method comprises the following steps: discretizing a current state equation according to a sampling period to obtain an initial discrete sliding mode observation equation; determining a proportional adjustment coefficient k based on the inductance parameters of the motor and the sampling period, weighting and adjusting the voltage related term and the sliding mode control term in the initial discrete sliding mode observation equation by using the proportional adjustment coefficient k, and constructing an improved sliding mode observation equation; extracting an extended back electromotive force based on the output of a sliding mode control law, wherein the contribution proportion of the high-frequency chattering component of the sliding mode control law output in the extended back electromotive force is weakened by the proportional adjustment coefficient; and inputting the extended back electromotive force into a phase-locked loop module to calculate the rotor position and speed of the motor to realize the closed-loop control of the motor.

The embodiment of the disclosure provides a kind of permanent magnet synchronous motor torque control method, device, storage medium and electronic equipment, wherein, method includes: obtaining the desired torque of permanent magnet synchronous motor, feedback torque and desired excitation current;According to the desired torque, obtain first torque instruction current;According to the difference of the desired torque and the feedback torque, obtain second torque instruction current;According to the first torque instruction current and the second torque instruction current, obtain third torque instruction current;According to the third torque instruction current and the desired excitation current control the torque of the permanent magnet synchronous motor, in turn, the quick response of torque feedforward control and the robustness characteristics of torque feedback control are ingeniously combined, the anti-interference performance of torque control is improved, the overshoot and pulsation of permanent magnet synchronous machine torque are reduced, and the steady-state deviation of step response is reduced.

An ultra-high reluctance topology rotor structure and a permanent magnet synchronous motor, the rotor structure comprising a rotor lamination having an outer circle, a magnetic field regulating unit being arranged in the circumferential direction of the rotor lamination, the magnetic field regulating unit having a magnetic pole center line coinciding with a geometric center line of the rotor lamination; the magnetic field regulating unit has N layers of magnetic steel groove structures arranged in stepped intervals; one layer of magnetic steel groove is arranged in the first layer, the one layer of magnetic steel groove having a connected one layer of magnetic steel region and one layer of air domain; three i layers of magnetic steel grooves are arranged in each layer from the second layer to the Nth layer. The scheme significantly improves torque density and wide-range efficiency, greatly enhances the weak magnetic expansion speed capability and the highest operating speed, reduces the amount of permanent magnets, effectively reduces the material cost, greatly reduces the peak current, reduces the capacity of the converter, and reduces the system cost.

The invention relates to a rotor (1) for an electric machine (2), in particular for a permanent magnet synchronous machine, - with a shaft (4) rotatable about an axis of rotation (3) and a support (5) connected to the shaft (4) in a rotationally fixed manner with receptacles (6) aligned in the axial direction (24), - wherein permanent magnets (7) are arranged in the recordings (6). The essential feature of the invention is that a non-magnetic, austenitic metal sleeve (8) is provided, which surrounds the carrier (5) and the permanent magnets (7).

The subject application discloses improved rotor assemblies containing permanent magnets, tailored for two distinct synchronous machine topologies—radial and axial flux machines.Both rotor structures incorporate elongated bodies having soft-magnetic elements strategically arranged between permanent magnet groupings.Uniquely, the soft-magnetic components feature an innovative conical geometry to focus magnetic flux.The permanent magnets positioned on each side of an element share identical polarity to strengthen flux.The particular shape of the intersection between soft-magnetic elements and permanent magnets allows spreading the stress linked to the centrifugal force applied to the permanent magnet during the motor operation.Radial rotors create a circumferential air gap, while axial rotors have an axial-oriented gap.Together, these advances aim to boost torque production and lower torque ripples to enhance overall performance.The combination of tapered soft-magnetic cones, optimized magnet polarity, and air gaps demonstrating advancements in high-power permanent magnet rotor engineering for specialized synchronous machines.

The invention relates to a central information controller of a multi-channel permanent magnet synchronous electromechanical servo system, and belongs to the technical field of servo control. According to the controller, an integrated hardware architecture of double DSP + high-speed double-port RAM (Random Access Memory) is adopted, and the design of a double-redundancy RS-422 communication interface and a hierarchical isolation power supply circuit is matched, so that multi-channel parallel cooperative control, multi-sensing information rapid processing and high-reliability communication are realized, and meanwhile, the controller has the advantages of miniaturization, low cost and strong anti-interference capability; the high-performance application requirement of the permanent magnet synchronous electromechanical servo system in the fields of numerical control machine tools, industrial robots, aerospace actuating mechanisms, radar antenna servo and the like can be effectively met, the technical defects of a traditional controller in the aspects of processing performance, size, cost and reliability are overcome, and the industrial application prospect is good.

The present invention relates to linear permanent magnet synchronous machines equipped with a device for minimizing the longitudinal edge effect. Intrinsically, this phenomenon gives rise to several limitations, such as: (i) a fairly marked amplification of the tooth force, which affects the quality of the force developed, (ii) an imbalance of the fluxes cut by the phases, resulting in unbalanced electromotive forces, and (iii) a local increase in transverse magnetic forces, which generates a vibration of the slider and annoying acoustic noise. The present invention proposes a device for minimizing the longitudinal edge effect in the case of long-stroke machines, whether tubular or planar in topology. It consists of two laminated ferromagnetic pieces having an "L"-shaped cross-section, mounted near the ends of the stator ferromagnetic circuit. Such a device allows for the collection of a portion of the flux generated by the slider poles located at the stator ends and its injection into the extreme stator teeth. The shape and location of these components are determined using a numerical dimensioning procedure. The proposed device improves the performance of long-stroke permanent magnet linear synchronous machines. Their integration into various sectors, such as energy, mobility, and robotics, is at stake.

System for providing motor control for an electromechanical brake when a motor control fails, wherein the system comprises the following: an electromechanical braking mechanism (110) comprising a permanent magnet synchronous machine (215), a rotor position sensor that is configured to to detect the position of a rotor of the permanent magnet synchronous machine (215), a motor current sensor and an electronic control (115) designed to: Determine if at least one of the rotor position sensor and the motor current sensor is malfunctioning. Generating a control signal to control the permanent magnet synchronous machine (215) and Activating the permanent magnet synchronous machine (215) using the generated control signal to generate a stator magnetic field to operate the rotor of the permanent magnet synchronous machine (215), where the control signal is a stator magnetic flux strength, includes a frequency of the stator magnetic field and a predetermined angular velocity of the stator magnetic field.

Systems, apparatuses, and methods to perform startup step detection in an internal permanent magnet synchronous machine are provided. Startup step detection may providing a motor comprising a rotor and stator, wherein the rotor may be positioned in one of six rotor step positions. The startup step detection may include determining which of the six rotor step positions the rotor is in. This may be performed by determining, prior to starting the motor, a sequence of voltage signals while taking current measurements for each voltage signal. The current measurements may be a change in current over time. Of the current measurements a largest maximum current measurement may be determined, which may be used to identify the current rotor step position.