Method for controlling a multiphase motor

Abstract

The present invention relates to a method for controlling a multiphase actuator, the method comprising: supplying a periodically varying voltage to each phase, the voltage having a periodic sequence of intervals Pi, the interval Pi having a constant duration and an amplitude An,i, where n corresponds to the serial number of the phase and i corresponds to the serial number of the interval; determining a target position PCi of the actuator rotor to define a sinusoidal voltage envelope, the actuator further comprising a movable member, a stator equipped with electric coils, a sensor for detecting the mechanical position of the movable member relative to the stator, and a microcontroller. The microcontroller determines the mechanical position of the mechanical member at time Tsensor, the microcontroller calculates the difference between the mechanical position and the target position PCi corresponding to the interval Pi at each time Tsensor of the time Tsensor, and the microcontroller calculates a coefficient k based on the difference, and the microcontroller weights the amplitude of the power supply applied to the phase by the coefficient k to supply a weighted amplitude voltage An,i*k to the phase.

Description

Field of the Invention

[0001] The present invention relates to the field of polyphase brushless actuators controlled by a microcontroller in a step mode. The present invention relates to both rotary actuators and linear actuators.

[0002] In a non-limiting manner, the present invention relates to the field of actuators for fluid control, where the fluid may or may not be a refrigerant.

[0003] Such an actuator typically includes a rotor provided with permanent magnets, which is moved by a magnetic field generated by a set of coils controlled by power electronics. Whether each coil is powered defines the relative position of the rotor with respect to the stator.

[0004] A full-step stepper motor has a limited number of discrete positions (usually as many as the positions of the magnetic poles on the stator), but a proportionally controlled stepper motor can improve accuracy. Since the motor has multiple equilibrium positions between two steps, the term "microstep" is used. In this patent, the term "step" will be interchangeably designated as a full step or a "microstep". Background Art

[0005] U.S. Patent US2013043822 is known in the prior art, and this U.S. patent describes a technical solution for controlling a stepper motor using a position feedback device, which has a resolution capability of 200 steps per revolution of the motor shaft for step offset detection and motor step recovery. The position deviation is calculated periodically and cyclically, subtracting the returned position from the corresponding commanded position to implicitly determine the load angle and operating state of the motor, where the load angle is defined as the angle between the maximum value of the magnetomotive force and the direct axis of the rotor (commonly referred to as the "d-axis"), that is, the angle difference between the magnetic field vector generated by the wound stator of the motor and the magnetic field vector of the rotor.

[0006] If the load angle is within the set allowable value range, the normal operation of the stepper motor along the programmed trajectory can be maintained without adjustment. However, if the load angle exceeds the limit of this range, it indicates that a step loss has occurred, and the system controller initiates an action to recover the lost motor steps to restore synchronization.

[0007] Patent application US2008100249 describes another example of controlling the rotation of a stepper motor, including the following steps:

[0008] - During the rotation of the motor, continuously determine the rotational position of the stator field relative to the rotor within the stepper motor; and

[0009] - When exceeding a first predetermined amount and the rotor lags behind the stator field, delay the rotation of the stator field to optimize the performance of the motor.

[0010] Patent US5029264 describes the application of a stepper motor for a mobile carriage;

[0011] - A detection device for detecting the angular position of the rotor of the stepper motor, which generates a pulse signal for each predetermined rotational angle of the rotor.

[0012] - A control device for counting the pulse signals from the detection device, detecting the position of the carriage based on the pulse signals counted by the control device, transmitting control signals for starting and stopping the carriage, and transmitting an initialization signal;

[0013] - A current switching device for counting the pulse signals from the detection device and changing the exciting current supplied to the coils of the stepper motor according to the pulse signals counted by the current changing device to perform closed-loop control. The current switching device also performs the stepper motor drive of the stepper motor in response to the initialization signal from the control device. The current changing device positions the rotor in a stable position and returns the count value to a reference value, starts the exciting current change control in response to the start control signal from the control device, and stops the exciting current change control in response to the stop command from the control device.

[0014] JP2007259568 discloses a stepper motor driving device having a microstep function, in which a sinusoidal current flows through the motor windings whenever an external drive pulse is applied and the basic step angle is segmented. The driving device includes: an angle detector for detecting the rotational angle of the rotor; a motion controller for calculating the exciting angle from the external control pulse and the rotational angle of the rotor; an inverter for driving the stepper motor; a current controller for controlling the current of the stepper motor; a current detector for detecting the motor current; and a current command generator for generating a current amplitude command. The driving device is configured such that when two different current commands are generated by the current command generator in the case where the motor is stopped, information related to the change in the output of the obtained angle detector is used to correct the angle command.

[0015] Disadvantages of the prior art

[0016] The technical solutions of the prior art result in relatively high current consumption in some cases, especially when the actuator has reached a stop, and lead to an electric energy level exceeding that required for controlling the position.

[0017] The technical solutions of the prior art cannot dynamically and continuously adjust the current supplied to the stator part, so that the current cannot be minimized according to the instantaneous load applied to the rotor. This inability to adjust according to the load means greater energy consumption and self-heating caused by the Joule effect of the stator coil, thus damaging the performance of the motor.

[0018] Patent US8810187B2 proposes to periodically monitor the movement of the rotor to verify compliance with the control steps, but does not provide any continuous monitoring of the load angle. In addition, it does not dynamically modify the amplitude of the current injected in each step.

[0019] Patent US2008100249 corrects the movement speed rather than the current.

[0020] Patent US5029264 relates to the BLDC control of a stepper motor that requires a PID controller. The PID controller requires a large amount of calculations and can produce setpoint overrun.

[0021] Patent JP2007259568 proposes to measure the position of the rotor to change the stepper control phase, but does not change the amplitude of the current. Summary of the Invention

[0022] The present invention relates to a method for controlling a multiphase actuator, which includes supplying a periodically varying voltage to each phase. The voltage has a periodic sequence of steps (pas) P i with a constant duration and amplitude A i where n corresponds to the serial number of the phase (for example, a three-phase motor has 3 phase serial numbers), and i corresponds to the serial number (rang) of the step (for example, a 48-step control for each electrical cycle has 48 serial numbers). Determine the target position PC n,i of the rotor of the actuator to define a sinusoidal voltage envelope. The actuator further includes a movable member, a stator equipped with electric coils, a sensor for detecting the mechanical position of the movable member relative to the stator, and a microcontroller. It is characterized in that: i · The microcontroller determines the mechanical position of the mechanical member at time T

[0023] · The microcontroller calculates the difference between the mechanical position and the target position PC 传感器 corresponding to the step P

[0024] · at each time T 传感器 of the time T 传感器 and the microcontroller calculates the coefficient k according to the difference; i corresponding to the step P i

[0025] ​· The microcontroller weights the amplitude of the power supply applied to the phase by a coefficient k to supply a weighted amplitude voltage A to the phase n,i * k(A n,i multiplied by k).

[0026] In the present invention, it is contemplated that a voltage according to pulse width modulation (PWM) is supplied to each phase of the motor. The coefficient k under discussion is a coefficient that modifies the duty cycle and thus modifies the average level of the voltage applied to each phase.

[0027] Compared with the prior art, the advantages of the technical solution proposed herein are: the dynamic range of control; adjusting to the actual position of the moving member at each time T 传感器 ; and the ability to operate even at zero speed or reduced speed, the principle being independent of the speed.

[0028] According to a preferred embodiment, the method includes at least one acquisition time T i for step P 传感器 of the mechanical position of the mechanical member, and more preferably includes at least four acquisition times T 传感器 .

[0029] The coefficient k may be proportional to the difference between the mechanical position and the target position PC i corresponding to step P i , but any other mathematical function may be used.

[0030] The present invention will preferably be used for a movable member that is a rotor of an actuator to avoid being hindered by errors caused by mechanical clearances, but the movable member may also be moved by the rotor via a motion conversion member.

[0031] In one embodiment, the rotor may move through multiple turns. The motion is helical, and the number of the turn relative to the initial position is determined by the norm of the signal transmitted by a two-dimensional magnetic sensor. In this case, the number of the turn is compared with a previously recorded value.

[0032] In another embodiment, the method includes a calibration step that includes: controlling the movement of the movable member to a mechanical stop; and detecting locking by reaching a threshold k 阈值 by the coefficient k; and recording in a memory the step P i corresponding to the reached threshold as the reference P0 of the movable member.

[0033] In another embodiment, the method includes the step of maintaining the movable member in a non-operating position, the step including: periodically measuring a coefficient k; and if the coefficient k exceeds a threshold, controlling the amplitude of the supply voltage of the phase.

[0034] Advantageously, the electrical phase control is modified to move the measured position of the rotor closer to the desired mechanical position.

[0035] The present invention as described will be particularly advantageous for controlling fluid control valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be better understood by reading the following detailed description of non-limiting examples of the invention with reference to the drawings, in which:

[0037] - Figure 1 is an isometric view of a control valve, which is given by way of example and can use the present control method;

[0038] - Figure 2 is Figure 1 a cross-sectional view of the control valve shown in

[0039] - Figure 3 is Figure 1 a longitudinal cross-sectional view of the control valve shown in

[0040] - Figures 4a, 4b and 4c show examples of magnetization variations of sensor magnets on the rotor of an electric motor controlled by the present control method;

[0041] - Figure 5 is a partial longitudinal cross-sectional view of a control valve according to another example in which the present control method can be used;

[0042] - Figure 6 is a separate view of the stator of a motor to which the present control method can be applied;

[0043] - Figure 7 is a schematic diagram of the load angle of a control motor to which the present control method can be applied;

[0044] - Figure 8 shows a typical operating algorithm of the present control method;

[0045] - Figure 9 shows a graph of the magnetic induction intensity detected by a magnetosensitive probe associated with one of the sensor magnets in Figures 4a to 4c;

[0046] - Figure 10 shows a method implemented on multiple turns of the rotor of an actuator according to the present invention;

[0047] - Figure 11 illustrates the operation of the method of the present invention illustrated using a graph;

[0048] - Figure 12 illustrates Figure 11 an enlarged view of

[0049] - Figure 13 illustrates the method of stop detection illustrated using a graph;

[0050] - Figure 14 illustrates the different voltage values applied to each phase of the motor;

[0051] - Figure 15 illustrates the dynamic modification of the value k according to the load applied to the rotor. DETAILED DESCRIPTION

[0052] Figure 1 is an isometric view of a first embodiment of a valve according to the present invention, which combines an electro - actuation assembly and a mechanical assembly in order to produce a flow path for a heat - transfer fluid.

[0053] Thus, the valve more particularly comprises an electric actuator (1) which translates a needle (not visible here) along a movement axis (3) by using an electric motor. The actuator (1) is fastened to a valve body (2) which includes a through - channel (20) for the heat - transfer fluid, the flow rate of the heat - transfer fluid being controlled by said needle. The electric actuator (1) includes a cover (19) on its upper part, and the electric actuator (1) is fastened to the valve body (2) by axial fastening means (4) such as screws or bolts.

[0054] Figure 2 is a top view of the first embodiment without the cover, which makes it possible to observe the radial - flux electric actuator that can be used in the present invention. Any other electric actuator that produces torque in terms of movement conversion can be used, for example, an electric actuator that uses the magnetic flux along the movement axis. The actuator (1) has a stator (6) formed by a stack of sheets forming teeth, on some of which are placed electric coils (25), in this case three coils which are 120° to each other. The stator (6) is housed in a housing (9) which may include a connector (5). In this view without the cover (19), the presence of a sealed cup - shaped member (16) can also be observed, inside which are housed the rotor of the actuator (1) and the needle to be moved, these elements being immersed in the heat - transfer fluid. The stator (6) is located outside the cup - shaped member so as to be isolated from the heat - transfer fluid.

[0055] Figure 3Is a longitudinal section of the valve according to this first embodiment. The actuator (1) is screwed onto the valve body (2) by using fastening elements (4). The valve body (2) has flow channels (20) for the introduction and extraction of the heat transfer fluid. The flow of the fluid is controlled by positioning the end of the needle (11) controlled by the electric actuator (1) along the axis (3) so that this end of the needle (11) approaches or moves further away from the needle seat (17). The rotor (12) includes a nut member (14). In this particular embodiment, the rotor (12) also forms a support for the yoke and the permanent magnet (13) here. The rotor moves the needle (11) by means of a connecting member which is a rigid connecting member in this case, but the connecting member can be indirect via a spring located at the joint (not shown). The movement of the rotor (12) and thus the movement of the needle (11) follow a spiral path, thus combining the rotation of the electric machine formed by the rotor (12) and the stator (6) and the necessary translation for screwing the nut member (14) onto the screw (15), where the screw (15) is fixed and rigidly connected to the valve body (2) in this case. This movement is spiral, but for a control valve, only the translational component is mechanically important, where the needle has a solid of revolution geometry.

[0056] The design shown here is particularly compact axially and has guides provided throughout the effective height of the sheet stack (10), which in this case are provided by the cooperation of the screw (15) with the nut (14) and by the cooperation of the body of the needle (11) with the inner surface of the fixed screw.

[0057] In Figure 3In the design, a position sensor of the needle (11) is shown. This magnetic principle sensor is located above the rotor (12) on the upper part of the valve. The magnetized magnetic element (7) is rigidly connected to the nut member (14), thus connected to the rotor (12) and thus connected to the needle (11). The magnet (7) is also inserted into the interior of the cup-shaped member (16). The magnet (7) has a magnetization intensity that is diametrically perpendicular to the rotation axis of the rotor or bipolar along the axis (3) of the rotor, or a magnetization intensity that rotates around an axis perpendicular to the axis (3). The magnetic element forms a magnetic field in a plane of the probe (19) perpendicular to the axis (3). As the rotor (12) rotates, the magnetic field will rotate synchronously with the rotor (12). Therefore, during the helical movement of the rotor (12), the magnetic element (7) moves away from or approaches the bottom of the cup-shaped member (16). A magneto-sensitive probe (8) is positioned facing the cup-shaped member (16) on the axis (3) and outside the cup-shaped member (16). The probe detects the angle of the magnetic field and the amplitude of the component of the magnetic field emitted by the magnetic element (7) perpendicular to the axis (3) or the norm of the component perpendicular to the axis (3) according to the application. Therefore, the movement away from or towards the magneto-sensitive probe (8) of the magnetic element (7) enables the modulation of the amplitude of the field detected by the probe (8) and the projection of an image of the position of the needle (11).

[0058] The probe (8) is supported by a printed circuit (18) located above the cup-shaped member (16) and below the cover (19). The printed circuit (18) can also support the connection points of the coils of the actuator (1) and the electronic components required to control the multi-phase electric motor.

[0059] The magnetic element (7) that generates the axial magnetic field is in the form of a magnet based on neodymium iron boron, ferrite, or samarium cobalt. Samarium cobalt material has the advantage that its magnetic properties change little according to temperature, thus minimizing the drift of the sensor signal and minimizing the influence of the temperature gradient between the fluid and the magnetic field measurement probe.

[0060] This small magnetic change according to temperature is useful when measuring the amplitude of the field to determine the axial position. The measurement of the angular position by comparing the amplitudes of two non-collinear magnetic components perpendicular to the axis (3) does not depend on the amplitudes of these components.

[0061] The probe (8) is a probe that measures at least two components orthogonal to the magnetic field, and the probe (8) can be a three-dimensional probe.

[0062] Figure 4a shows the magnetized magnetic element (3) that generates the field required for the measurement probe and is magnetized diametrically, so as to have a vector located in a plane perpendicular to the rotation axis (3) of the rotor.

[0063] Figure 4b shows a magnetized magnetic element (7) that generates the field required for the measurement probe and is magnetized in a bipolar manner, where the two parts of the magnetic element are magnetized according to two vectors in opposite directions that are parallel to the axis of rotation (3) of the rotor.

[0064] Figure 4c shows a magnetized magnetic element (7) that generates the field required for the measurement probe and is magnetized according to a rotating magnetization intensity, and the orientation of the magnetization intensity inside the magnetic element rotates around an axis (22) perpendicular to the axis of rotation (3) of the rotor.

[0065] Figure 5 shows Figure 1 、 Figure 2 and Figure 3 an alternative construction where the radial flow electric motor is replaced by a claw pole motor (23) that includes a set of cut and folded sheets (24) associated with a coil (25) to form the phases of the electric motor. The probe (8) welded to the PCB (18) is held in position close to the axis (3).

[0066] Figure 6 shows a technical solution for protecting the magnetic measurement probe from the interfering field generated when current passes through the stator coil (25). A stack of additional sheets (26) surrounds the coil to provide a preferred magnetic path for the flux generated by these coils.

[0067] Figure 7 a、 Figure 7 b、 Figure 7 c and Figure 7 d are schematic diagrams of the stator vector (40) and the rotor vector (41). In this figure, the vectors u, v, w are the orientations of the torques generated by each of the phases of the motor employed. This is called the "Fresnel diagram".

[0068] The stator vector (40) is the sum of the electrical microstep control signals at the terminals of the stator coil located in a plane perpendicular to the axis (3).

[0069] The rotor vector (41) is determined by analyzing the signal transmitted by the probe (8), and this analysis is converted into a Fresnel diagram based on the position signal from the position sensor, the reference position, and the knowledge of the number of pole pairs.

[0070] The load angle corresponds to the angle between the stator magnetic field vector (40) and the rotor magnetic field vector (41). The resultant torque generated at the rotor by the power supply at the stator varies from zero torque (50) when this angle is 0° to maximum torque when the vectors are 90°. The torque is proportional to the sine of the load angle and the supply current.

[0071] Assume that with no load on the rotor, the load angle is equal to 0°, and the stator vector and the rotor vector are collinear. The actual angular position of the rotor is the same as the control position.

[0072] When a force is applied to the rotor, for example, by means of a braking torque, or a load torque, or a driving torque, the load angle (42) increases and then the load angle (42) is no longer equal to 0°. This is shown in Figure 7 a, Figure 7 b, Figure 7 c and Figure 7 d in four figures, where the torque generated at the same supply current increases. When this load angle exceeds 90°, the applied torque decreases and may lead to a loss of synchronism between the rotor field and the stator field, called rotor stall.

[0073] Figure 8 The process of controlling the motor using this load angle is shown in. This offset is determined periodically - at least once or more per microstep. If the load angle (42) is constant, the computer keeps the value of the coefficient k constant. If the load angle (42) increases or decreases, the computer modifies the value of the coefficient k accordingly, higher or lower, to modify the control voltage (via different duty cycles) and thus modify the amplitude of the current injected into the phase. Preferably, when the load angle is zero, the coefficient k is zero, and when the load angle is 90°, the coefficient k is maximum.

[0074] The coefficient k can be a coefficient proportional to the load angle, but all other mathematical functions (quadratic or other functions) can be considered.

[0075] Figure 9 The different magnetic field components measured by the magnetic sensor are shown. In this case, the X component (45) and the Y component (46) are located in a plane perpendicular to the axis of rotation (3) along two orthogonal vectors between a position (47) far from the probe and a position (48) close to the probe. In this non-limiting example, the positions are separated by approximately four turns.

[0076] Figure 10 Illustrated by Figure 9Calculations are performed on the components. The ratio of these two components (45) and (46) enables the angle of the rotor magnetic field (41) to be calculated by computing the arctangent of this ratio. The signal (41) has four periods, and these four periods correspond to four rotational revolutions made by the rotor. The calculation of the norm of the measurement field (49) enables the distance of the magnet (7) relative to the measurement probe (8) to be estimated. This distance can be measured directly using this magnetic field module or interpolated. In the case of interpolation, with the aid of an angle sensor, the position of the rotation is precisely known, and the variation in the amplitude of the field is sufficient to determine in which turn the rotor (12) is located. Thus, the axial position of the rotor along the screw can be very precisely known by analyzing these two measured values of the angle (41) and the amplitude (49).

[0077] Figure 11 An example of an electrical signal calculated by comparing the control signal (40) and the angle value (41) measured by the sensor is shown. This graph shows the variation of the signal over time in microsteps (left - hand scale) and torque (right - hand scale).

[0078] In the example provided, the following aspects during the movement from a stationary position (initial time) in a given direction against a constant load are plotted: the variation in microsteps of the stator position (40) corresponding to the desired movement; the variation in microsteps of the measured position (41) of the rotor; and the load angle (42) resulting from the difference between the position (40) and the position (41), also in microsteps. As long as the load angle (42) is not sufficient to generate a torque greater than the load, no movement is observed at the rotor. As soon as the load angle reaches a threshold depending on friction and the load (53), the rotor speed synchronizes with the stator field (40) at an approximately constant load angle as when the load is constant. At the end of the movement (54), when the power supply to the coil is cut off or the stator field vector is kept unchanged, the rotor remains in place due to the irreversibility of mechanical conversion. Before the power supply is stopped, the load angle (42) remains at its last value. There is a residual offset (51) between the desired position (40) and the actual position (41) of the rotor, and this offset is equal to the load angle (42), but this is known, and this can be compensated for by modifying the control (40) by a value equal to the value of this residual offset (51) so that the rotor reaches the desired position (55).

[0079] Figure 12 Illustrates the discretization phenomenon caused by the measurement of the sensor at time T 传感器 where there are at least four periods represented in microsteps (56). This graph shows the variation of the signals (40, 41, 42) over time in degrees.

[0080] Figure 13Illustrated is the use of a load angle (42) to detect a mechanical stop when the actuator moves. The graph shows the variation of signals and amplitudes (40, 42, 52) over time in degrees. Then, when the maximum allowable current is reached, when the load angle (42) exceeds a threshold (52), for example, exceeds 100°, it can be considered that the rotor has mechanically reached this stop. Thus, the mechanical stop can be known precisely.

[0081] Figure 14 Illustrated are the different voltage values applied to each phase of the motor according to the method of the present invention. The number of steps is shown on the X-axis. The Y-axis specifies the voltage value, which is represented as a register value programmed in the microcontroller, and this voltage value is used to keep the deviation between the mechanical position and the target position constant. All steps P i have a step duration and an amplitude A determined for each step n,i *k. The value of the amplitude of each step is different to form a sinusoidal periodic function of the control voltage, and the period of this sinusoidal periodic function is shown here. According to the desired harmonic content, the shape of the sine wave can be changed.

[0082] When the deviation between the mechanical position and the target position remains constant, the voltage value follows one of the curves of the periodic function A n,i *k (for example, k = 0.75). When the deviation between the mechanical position and the target position changes, that is, when the deviation increases or decreases, the microcontroller calculates and applies a coefficient k of a higher or lower value of the register to adjust the voltage level applied to the phase of the motor. This results in a higher or lower phase current and thus a higher or lower torque of the motor to adjust to the measured offset. The value of the coefficient k can jump from one step to another according to the calculation of the microcontroller, for example, from k = 0.75 at step P5 to k = 0.25 at step P6.

[0083] It is important to note that the duration of each step is determined by dividing the duration of the voltage period by the total number of steps in one period. When the rotational speed of the motor is fixed, the duration width of each step is constant and the same. When the rotational speed of the motor changes, the duration width of the steps calculated and applied by the microcontroller varies according to the desired motion speed of the motor.

[0084] It is also important to note that each voltage value of amplitude A n,i *k is obtained from a constant voltage source by adjusting the duty cycle and by a modulation technique - pulse width modulation (PWM). The teachings in the field of PWM are well known in the prior art and will not be discussed further herein.

[0085] Figure 15Shows the dynamic control modifications allowed by the present invention. In the example shown, the variations in the stator position (40) and the measured position of the rotor (41) are plotted on the left-hand ordinate in degrees; on the right-hand ordinate, the load value (53) and the value of k (57) at the rotor are plotted on a scale normalized from 0 to 1. The number of steps is shown on the X-axis. The observed periodic pulses are attributed to the clarity difference between the motor steps and the acquisition of the rotor position.

[0086] At the initial time, the rotor is stationary and the stator position (40) is at zero, as is the value of k (57). Starting from this rest position (initial time), a constant load (53) of approximately 0.3 (standard value) is applied. Due to inertia and mechanical clearances, the rotor remains in the zero position. When a forward movement command is issued to the motor, the stator position (40) increases. As long as the load angle caused by the difference between the stator position (40) and the rotor position (41) is not sufficient to generate a torque greater than the load, no movement is observed at the rotor. This causes the load angle to increase and, consequently, the value of k (57) to increase from step P0 to step P7.

[0087] As soon as the load angle reaches a threshold depending on friction and load, the rotor speed synchronizes with the stator field (40) at an approximately constant load angle as when the load is constant. From step P7 to step P16, the value of k remains around the value of 0.5 (standard value).

[0088] After step P16, the load increases from approximately 0.3 to 0.55 (standard value). Consequently, the load angle increases until it reaches a new value corresponding to an average value of k of 0.7. This value remains almost constant until step P27.

[0089] From step P27 to step P40, the load decreases from approximately 0.55 to 0.17. Consequently, the load angle decreases, which causes k to decrease to an average value of 0.4.

[0090] Figure 15 Shows how the instruction dynamically modifies the value of k (and thus the value of the average current flowing into the motor) according to the load applied to the rotor by virtue of the inherent relationship between the load angle and the value of k.

[0091] Figure 15 The functional example is by no means restrictive but is given only by way of an example of dynamic operation.

[0092] Throughout the sequence, the control speed defined by the duration of the voltage steps is always constant, and only the value of k, and thus the amplitude of the voltage steps, and thus the amplitude of the current flowing to the motor coils, vary according to the load applied to the rotor.

[0093] Minimization of power consumption

[0094] The present invention also relates to a method for controlling a multiphase actuator according to the main claim, which method makes it possible to reduce the current consumption according to the following different steps:

[0095] - Dynamically correct the load angle according to the general teachings described in the present application until the load angle is less than a first fixed threshold, which is usually 5°;

[0096] - Put the microcontroller in the standby state and stop supplying power to the motor phases. While waiting for the wake-up command and continuing to measure the load angle, the microcontroller only consumes minimal energy;

[0097] - As long as the load angle exceeds a second fixed threshold, which is usually 80°, the microcontroller is woken up, and then power is supplied to the phases of the motor to reduce the load angle until the first fixed threshold is reached.

[0098] Dynamic estimation of mechanical clearance

[0099] The present invention also relates to a method for controlling a multiphase actuator according to the main claim, which method makes it possible to continuously or according to a desire learn the mechanical clearance present in the actuator (by the possible presence of a mechanical reduction gear inserted between the rotor of the actuator and the movable output member), and which method has the following steps:

[0100] - Drive the movable member along a plurality of steps Pi in a first direction of movement;

[0101] - Stop the movement and drive the movable member in a second direction of movement;

[0102] - Measure the load angle and determine the maximum value;

[0103] - Determine the mechanical clearance such that the mechanical clearance is equal to the maximum value of the previously measured load angle;

[0104] - Correct the load angle according to the teachings described in the present application, the correction taking into account the previously determined mechanical clearance.

[0105] Predictive maintenance

[0106] The present invention also relates to a method for controlling a multiphase actuator according to the main claim, which method makes it possible to predict the maintenance requirements, and which method has the following steps:

[0107] - A software-defined mechanical clearance threshold above which the actuator is considered to be damaged or worn;

[0108] - Regular learning during the lifetime of the vehicle with the mechanical clearance as described above;

[0109] - When the measured mechanical clearance has reached or is greater than a defined mechanical clearance threshold, send information to the external control unit of the actuator.

[0110] Dynamic adjustment of docking speed

[0111] The invention also relates to a method for controlling a multiphase actuator according to the main claim, which makes it possible to generate a speed profile suitable for reaching the end (or stop) of the mechanical travel at a reduced speed, and the method has the following steps:

[0112] - Define the speed profile according to the position of the movable member within its travel;

[0113] - Perform regular learning during the life of the vehicle with the mechanical clearance as described above;

[0114] - Consider the mechanical clearance as a function of the movable member in the speed profile at the position to ensure a constant docking speed at one end of the actuator travel.

Claims

1. A method for controlling a multiphase actuator, the method comprising: A periodically varying voltage is supplied to each phase, the voltage having a periodic sequence of steps P i where the step P i has a constant duration and amplitude A n,i , where n corresponds to the phase number and i corresponds to the step number; determining a target position PC i of the rotor of the actuator to define a sinusoidal voltage envelope, the actuator further comprising a movable member, a stator equipped with an electric coil, and a sensor and a microcontroller for detecting the mechanical position of the movable member relative to the stator, characterized in that: · The microcontroller determines the mechanical position of the movable member at time T 传感器 ; · The microcontroller at the time T 传感器 At each time T 传感器 calculates the difference between the mechanical position and the target position PC i corresponding to the step P i and the microcontroller calculates a coefficient k based on the difference; · The microcontroller weights the amplitude of the power supply applied to the phase by the coefficient k to supply a weighted amplitude voltage A to the phase n,i *k, where the coefficient k is dynamically modified by the microcontroller according to the load applied to the rotor.

2. The method for controlling a multiphase actuator according to claim 1, characterized in that, The method includes at least one acquisition time T for step P of the mechanical position of the movable member i thereof 传感器 .

3. The method for controlling a multiphase actuator according to claim 1, characterized in that, The method includes at least four acquisition times T for step P of the mechanical position of the movable member i thereof 传感器 .

4. The method for controlling a multiphase actuator according to claim 1, characterized in that, The coefficient k is proportional to the difference between the mechanical position and the target position PC corresponding to the step P i of the i step P 5. The method for controlling a multiphase actuator according to claim 1, characterized in that, The movable member is the rotor.

6. The method for controlling a multiphase actuator according to claim 1, characterized in that, The movable member is moved by the rotor via a motion conversion member.

7. The method for controlling a multiphase actuator according to claim 5, characterized in that, The rotor is capable of moving through multiple turns.

8. The method for controlling a multiphase actuator according to claim 7, characterized in that, The rotor is capable of moving through multiple turns in a helical motion, and the number of the turns relative to the initial position is determined by the norm of the signal transmitted by the two-dimensional magnetic sensor.

9. The method for controlling a multiphase actuator according to claim 1, characterized in that, The locking of the movable member or the locking of the rotor is determined by the coefficient k reaching a threshold value k 阈值 to be determined.

10. The method for controlling a multiphase actuator according to claim 1, characterized in that, The method includes a calibration step, the calibration step including: controlling the movement of the movable member to a mechanical stop; and detecting locking by the coefficient k reaching a threshold k 阈值 and recording in a memory the step P corresponding to the reached threshold i as a reference P0 for the movable member.

11. The method for controlling a multiphase actuator according to claim 1, characterized in that, The method includes the step of holding the movable member in a non-operating position, the step including: periodically measuring the coefficient k; and if the coefficient k exceeds a threshold, controlling the amplitude of the supply voltage of the phase.

12. The method for controlling a multiphase actuator according to claim 1, characterized in that, The electrical phase control is modified to move the measured position of the rotor closer to the desired mechanical position.

13. The method for controlling a multiphase actuator according to claim 8, characterized in that, The number of the turns is compared with a previously recorded value.

14. A fluid control valve using a method for controlling a multiphase actuator according to any one of claims 1 to 13.

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