Control circuit for an electric motor

Abstract

The invention relates to a circuit (100) for controlling a motor (24) comprising a plurality of windings and an output shaft, the circuit comprising: - means (221, 222, 223, 231, 232, 233, 52, 54, 55) for powering each winding of the motor and a first loop (10) for controlling at least one current supplied to the windings of the motor; - a second loop (20) for controlling the angular velocity of the motor, the output of this loop forming an input of the loop (10) for controlling at least one current supplied to the windings of the motor; - a third loop (30) for controlling the position of the output shaft, the output of this loop (30) forming an input of the loop (20) for controlling the angular velocity of the motor.

Description

[0001] Description

[0002] TITLE: CONTROL CIRCUIT OF AN ELECTRIC MOTOR

[0003] TECHNICAL FIELD AND PRIOR TECHNOLOGY

[0004] The field of the invention is that of the control of an electric motor, which forms for example a valve actuator, particularly in the automotive field.

[0005] It also relates to custom integrated circuits for the control and management of an electric actuator including an electric motor, a gear train, etc.

[0006] We know the uses of such circuits, but they are bulky and expensive. General-purpose circuits like these often have additional resources that are oversized for this type of application.

[0007] The bulky aspect is clearly shown in figure 3, in which a circuit 110 is coupled to a gear train 112.

[0008] The aim is to create a circuit with a reduced surface area or footprint, while also reducing costs.

[0009] We are also looking to create an integrated circuit adapted to this type of application. Thanks to this adaptation, such a circuit would save on components and have a suitable, rather than oversized, footprint.

[0010] We are also looking for a circuit for more robust motor control, faster processing, parallel processing of operations and energy savings.

[0011] We also seek to create a robust circuit, enabling the management of internal states, preferably with diagnostic characteristics and / or one or more communication functions with external circuits, for example of ECU or LIN type.

[0012] DESCRIPTION OF THE INVENTION

[0013] The invention aims to remedy at least partially the problems and drawbacks mentioned above.

[0014] It concerns a circuit of reduced overall complexity, making it possible in particular to dispense with the presence of a microcontroller and / or microprogramming ("firmware").It first concerns a control circuit of an electric motor, in particular of an electric actuator, for example for a fluidic or hydraulic circuit of a motor vehicle, comprising a plurality of windings and an output shaft, this circuit comprising: means of supplying electrical or voltage to each winding of the motor and a first loop, of control of at least one current supplied to the windings of the motor; this first loop may be of the PID type; a second loop, of control of the angular speed of the motor, the output of this loop forming an input of the loop of control of at least one current supplied to the windings of the motor; a third loop of control of the position of the output shaft, the output of this third loop forming an input of the second loop of control of the angular speed of the motor; this third loop may also be of the PID type.

[0015] A control circuit according to the invention is advantageously implemented in the form of an ASIC. The invention employs parallel control loops, resulting in a significant gain in the dynamics of the control system. Data processing speed can also be improved, by a factor of 3 compared to sequential control methods.

[0016] A circuit according to the invention consumes less power than known circuits of this type, thus allowing for better use of the battery system in a vehicle. Indeed, a circuit according to the invention does not implement all the operations present in general-purpose microcontroller boards.

[0017] Preferably, the voltage uses hardware components, which is safer compared to a software solution.

[0018] In a particular embodiment, the first control loop includes means for measuring said current, the measured current being comparable to the output of the second control loop. The first control loop may advantageously include means for dividing the result of said comparison by a supply voltage (BVDD), for example, the high supply voltage, and means for supplying said plurality of motor windings.

[0019] This supply voltage corresponds to, or is approximately equal to, or represents the circuit's supply voltage; however, overvoltage protection and / or reverse polarity protection and / or one or more filtering functions may be applied to this circuit supply voltage, in which case this supply voltage is preferably the one obtained after implementing these additional functions. The circuit's supply voltage is generally between 8 and 18 volts; for example, it is 12 V.

[0020] Implementing voltage division by voltage difference (BVDD) in the first loop allows for voltage compensation (or voltage anticipatory compensation) that solves a control problem, particularly with PWM: since the motor voltage is equal to the PWM duty cycle multiplied by the supply voltage (motor voltage = duty cycle x BVDD), a variation in battery voltage, for example from 12 V to 16 V, in automotive applications would lead to inconsistent motor voltages for the same PWM duty cycle, resulting in unpredictable current regulation and motor performance. By dividing the current error signal by BVDD, especially before generating the PWM duty cycle, the system normalizes the control signal.Thus, when the motor requires 6V, it automatically calculates a duty cycle of 50% for a 12V supply or 37.5% for a 16V supply, ensuring that the motor always receives the required voltage, regardless of battery fluctuations. This compensation guarantees constant torque regardless of supply voltage variations, a faster current loop response without supply voltage disturbances, and improved control.

[0021] The first loop may include:

[0022] - a pulse width modulator (PWM); as explained above, division by the supply voltage is preferably carried out before pulse width modulation;

[0023] - and possibly a phase signal generator, which may be equipped with spread spectrum clocking to ensure electromagnetic compatibility (EMC) and / or reduce electromagnetic interference (EMI).

[0024] In a circuit according to the invention, the power supply means for each winding of said plurality of motor windings may include a controller and a voltage divider. Preferably, the controller is of the "Break-Before-Make driver" type, or non-overlapping or non-short-circuiting, or of the "Break-Before-Make driver" type.

[0025] In a circuit according to the invention, the 2 e A loop, for example of type "PID", can include:

[0026] - means for estimating an angular velocity based on the time elapsed between changes in the position of the rotor relative to the stator; for example, a BEMF (back electromotive force) comparator can identify where the rotor is located relative to the motor stator; the change in the rotor's position can then be derived over time to find the angular velocity of the rotor; - and / or means for comparing a detected angular velocity to an angular velocity setpoint; for example, the difference between the detected angular velocity and the angular velocity setpoint forms an error signal that allows the first loop to be controlled (for example: since the speed and current of the motor are related by the motor constant, the output of the speed control loop can serve as the input for the current control loop;the output of the speed loop is in speed, then a required torque is determined using the characteristics of the motor, finally the torque setpoint is converted into a current setpoint using the motor torque constant, which is the input of the innermost current regulation loop);

[0027] - and / or an angular velocity control loop filter to suppress noise in motor speed control requests;

[0028] - and / or an anti-winding device to prevent saturation due to the addition of integral error over time.

[0029] According to one embodiment, the speed is detected from the BEMF of the motor, a BEMF comparator enabling identification of where the rotor is relative to the motor stator; the change in position of the rotor can then be derived with respect to time to find the angular velocity of the rotor.

[0030] In a circuit according to the invention, the third loop may include at least one sensor to measure the position of the output shaft. The detected position is then fed into the input of a comparator for comparison with a desired position, the difference at the output forming an input for the second loop. The third loop may include:

[0031] - means forming a multiplier of the difference at the output of said comparator, the output of this multiplier being applied to the input of the second loop;

[0032] - and / or means implementing a Kpp function of dynamic velocity profile generator based on the error difference between a requested position and an actual position.

[0033] A circuit according to the invention may further include: means for, or means configured or programmed for, detecting a motor blockage, based on the signals provided by the first loop, the second loop and the third loop; means may also be provided to implement a motor release function when the motor is blocked; and / or means, or means configured or programmed, to implement a self-learning function, to determine the stopping positions of the motor output shaft; and / or means, or means configured or programmed, to implement a state machine that controls the switching between different circuit states, for example between a calibration state, an output shaft control state, and one or more motor stop mode(s);and / or means or configured or programmed means to filter the step of the actuators or of the actuator to prevent them or the actuator from implementing a step smaller than a programmed minimum step.

[0034] The output of at least one of the means for filtering the step of the actuators and / or of the means for implementing an unlocking function, and / or of the means for implementing a self-learning function can advantageously form a reference input of a comparator of the third loop, to which a detected position is compared.

[0035] A circuit according to the invention may include: means for supplying voltage to the circuit, for example of the charge pump type; and / or means for detecting an overcurrent supplied to at least one of the windings of the motor; and / or means for detecting an oversupply of voltage, or an undersupply of voltage, or an error in supplying voltage; and / or means for detecting an error in motor rotation and / or means for detecting an error in position; and / or means for interfacing or forming an interface, for example of the PC type, for example in order to configure and / or and program the circuit and / or means for interfacing, or forming an interface, for example with a local network and / or with an electronic control unit (ECU).

[0036] A circuit according to the invention may further include means for supplying voltage to the circuit.

[0037] The first control loop may include pulse-width modulation (PWM) means, with voltage division by the supply voltage (VDD) being performed before the pulse-width modulation. A circuit according to the invention may include means for implementing one or more protection functions against overvoltages and / or reverse polarity and / or one or more filtering functions of a circuit supply voltage; these means may be applied to this circuit supply voltage, the supply voltage (VDD) of the means supplying voltage to said plurality of motor windings being that obtained after said one or more functions (or being that obtained downstream of the means applying this or these protection function(s)).

[0038] The invention also relates to a control system for a moving part, comprising an electric motor having a plurality of windings and an output shaft for actuating said moving part, and a control circuit, according to the invention, for the electric motor.

[0039] The invention also relates to a moving part, for example a valve, of a fluidic or hydraulic circuit, comprising a control system according to the invention.

[0040] The invention also relates to a fluidic or hydraulic circuit, comprising at least one movable control element according to the invention.

[0041] The invention also relates to a motor vehicle comprising a fluidic or hydraulic circuit according to the invention.

[0042] BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Other aspects, objectives, advantages, and features of the invention will become clearer upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0044] • Figure 1 is an example of a circuit according to the invention;

[0045] • Figure 2 is another example of a circuit according to the invention.

[0046] • Figure 3 is an example of a control circuit for a motor coupled to a gear train;

[0047] • Figure 4 is an example of a control circuit, according to the invention, of a motor coupled to a moving part.

[0048] DETAILED DESCRIPTION OF SPECIFIC METHODS OF IMPLEMENTATION

[0049] In the figures and throughout the description, the same reference numerals represent identical or similar elements. Furthermore, the various elements are not drawn to scale to ensure clarity. Moreover, the different embodiments and variants are not mutually exclusive and may be combined. Unless otherwise stated, the terms "approximately," "around," and "in the order of" mean within 10%. Furthermore, the terms "between ... and ..." and equivalents mean that the limits are inclusive, unless otherwise specified.

[0050] Two examples of circuit embodiments 100 and 100' according to the invention are illustrated in Figures 1 and 2. These are ASIC-type circuits, comprising digital and analog functions, the differences being notably in the presence within the circuit (case of Figure 2) or outside of it (case of Figure 1), of circuit protection means against overvoltages and / or reverse voltage. The main difference between these two examples 100 and 100' is that circuit 100' integrates overvoltage and reverse polarity protection within the chip itself, which slightly increases its size compared to that of circuit 100. Each of these two circuits implements three control loops: an internal loop 10 controls the current supplied to the windings of the electric motor 24 and therefore the torque supplied by the motor; this loop, for example, has a bandwidth of 10 kHz;

[0051] Another loop 20 controls the angular speed of the motor; the output of this loop 20 forms an input to the internal loop 10; this loop has, for example, a bandwidth of 1 kHz;

[0052] Another loop 30 controls the position of the output element; the output of this loop 30 forms an input of the loop 20 which controls the angular speed of the motor; this loop has, for example, a bandwidth of 250 Hz; according to one embodiment, the output of the control loop 30 (position control) is not directly transmitted to the loop 20, but there is an intermediate function, denoted Kpp (see below), to calculate the optimized speed profile and then choose the correct speed setpoint.

[0053] A circuit and a processing according to the invention therefore implement parallel regulation loops, which allows a significant gain in terms of control dynamics.

[0054] In loop 10, three dividers 22i, 222, and 22a (motor driver circuits, also called "bridges," located on the right side of Figure 3) are connected to the terminals of a brushless DC motor 24. In this example, the circuits 22 contain NMOS transistors, but PMOS transistors can be used as explained later. Nodes MOUT1, MOUT2, and MOUT3 supply the motor windings with a voltage divided by each divider.

[0055] In one example, each of the motor control circuits 22i, 222, 22a has 2 MOSFET type switches, one on the top side and one on the bottom side, the "half-bridge" transistors on the bottom and top sides being, for example, NMOS.

[0056] According to an example implementation, a half-bridge of either of the divisors:

[0057] - is capable of delivering a maximum direct current of 1 A;

[0058] - and / or has a typical resistance of 2 O, for example 2.8 O maximum.

[0059] The current flowing through the motor windings is measured using a small value (e.g. 10 mO) accurate 26 Rsense resistor outside the circuit.

[0060] The voltage across this resistor 26 can be measured using an amplifier 28 and an A / D converter comprising a ZAmod modulator 32i and a decimation filter 322. Such a converter, for example, implements an oversampling technique allowing a simple, low-power circuit to perform a high-precision analog-to-digital conversion.

[0061] The measured current is compared with the input ("Drive Current Control Input") of a comparator 34 and the difference is filtered by a filter 36. The output of the speed controller is in fact a torque reference, the torque and speed of a motor being related (a certain torque allows a given speed to be reached); this torque setpoint can be translated into a current setpoint using the motor torque constant.

[0062] The output of filter 36 is divided, by the divider means 37, by a measurement of the transistor supply voltage (for example, the BVDD voltage, i.e., the high supply voltage of the transistors) to determine the duty ratio to be implemented by the pulse-width modulator 38 (reference 38a designates a phase signal generator). The 3 PWM outputs are connected to the 3 BBM drivers (or controllers) 23i, 232, 23a (Break-Before-Make driver type controllers, also called non-overlap or non-short-circuiting controllers or break-before-connect type controllers); each of these drivers controls one of the circuits 22i, 222, 22a. The 38a phase signal generator can be equipped with spread spectrum clocking to ensure electromagnetic compatibility (EMC) and / or reduce electromagnetic interference (EMI).

[0063] This type of circuit has the following advantages: It prevents cross-conducting when two transistors on the same branch of the inverter are activated simultaneously, which would create a short circuit across the power supply terminals, cutting off the path of current to a transistor before creating a new one.

[0064] It ensures smoother transitions between the different phases of the engine, creating less torque ripple effects in the control system and increasing the engine's operating efficiency.

[0065] It protects the power electronics.

[0066] As an example, the frequency range of the 38 PWM modulator is between 10 kHz and 20 kHz.

[0067] The BVDD division, prior to pulse-width modulation, allows the loop to be freed from the supply voltage. Each controller 23i, 232, 23a ensures that, for each half-bridge of the dividers, when one switch is open (OFF) and the other switches are closed (ON), there is no time interval during which they are both conducting, which would result in a current from the supply (BVDD) to ground and a loss of energy (which each controller 23i, 232, 23a allows through the Break-Before-Make function).

[0068] In this example, the transistors in components 22i, 222, and 22a are NMOS type. A charge-pump device 52, using a CCP capacitor 54 connected to the circuit, provides a voltage higher than the supply voltage provided by means 55 to supply the high-side supply voltage to the transistors. Alternatively, PMOS transistors can be used as high-side transistors or for the high voltage, eliminating the need for device 52 and capacitor 54, but resulting in a slight increase in circuit size, unit cost, and power dissipation.

[0069] The circuit can be coupled to power supply means 55, including, for example, FET transistors; the circuit can include overvoltage and reverse voltage protection means 59. Means 55i, 552 can provide low and high supply voltages to the transistors that form the voltage dividers 22i, 222, 22a. These means can be coupled to means 53 for regulating these voltages.The means 53 include, for example, voltage regulator circuits, from which it is possible to derive the voltage BVDD to be supplied to the transistors, VDDA (for example 1.5 V), VDDD (for example 1.5 V) and, for example, 5 V; voltage rails can be used to power different functions of the chip, for example to provide a power supply (for example: 5V) to the sensor 62 (external to the circuit in the case of the embodiments of Figures 1 and 2); other operations or functions of the circuit or chip may require less power, the circuit or chip may therefore include voltage supplies, different from the means 55 and / or 55i, 552, for example different voltage rails;.

[0070] In loop 20, three comparators 56 (of the BEMF, or back electromotive force, type) determine the position of the rotor relative to the motor stator. The motor's angular velocity is calculated, by means 57, by differentiation, based on the time elapsed between position changes detected by these comparators; in other words, the rotor's position change can be differentiated over time to find the rotor's angular velocity. The angular velocity thus detected is compared (using comparator 63) to an angular velocity setpoint 62, and the difference is filtered by a filter 58, the output of which is applied to an input of comparator 34.

[0071] In loop 30, a Hall effect sensor 62 is used to measure the position of the output shaft. The signal from the sensor 62 is filtered by a filter 63, and the angle (or position) of the shaft is calculated by means 67. This detected position is compared with the requested position (using comparator 64), which is received on the LIN interface 65 (Local Interconnect Network), or defined by control functions implemented by means 72, 74, 76 (see below) and the difference (which can be multiplied by Kpp using a multiplier 66) at the output forms an input for the angular velocity control (loop 20).The requested position can be multiplied by Kpp, or the intermediate Kpp function can be implemented, because the circuit—the chip—can incorporate calculation logic to reach a requested position. However, a velocity is not always constant but can be given by a profile (for example, constant acceleration, phase, and deceleration). Kpp is a dynamic velocity profile generator function based on the error difference between the requested position and the actual position. It allows the generation of an optimal velocity trajectory with constant acceleration and deceleration phases to reach the target position.We can multiply the requested position by Kpp, or implement the intermediate function Kpp, so that the circuit has an integrated calculation logic in order to reach a requested position optimally (the speed is not always constant but can rather have a profile comprising one or more acceleration phase(s), and / or one or more constant phase(s) and / or one or more deceleration phase(s), which is represented by Kpp).

[0072] The Kpp function, for example, is a velocity profile generator (or discrete velocity profile generator) that dynamically converts position error into velocity commands using configurable motion profiles and transition coefficients. It implements one or more N-phase S-curve motion control algorithms (or S-curve motion profiles), for example, N = 1, for trajectories with smooth acceleration and / or deceleration, and optionally a simple triangular profile for very small position deviations (e.g., less than a predetermined limit, such as 10°), consisting of only half acceleration and half deceleration. This function generates jerk-controlled profiles that eliminate mechanical stress and resonance, whereas simple proportional gains create abrupt velocity changes, which can lead to vibration and wear.

[0073] This function is preferably based on phase switching in position rather than on time, which makes it more resistant to load variations and disturbances.

[0074] An algorithm for implementing such a motion control function in S uses one or more parameters such as a maximum allowable acceleration, and / or a maximum allowable speed, and / or a maximum 3rd order derivative (of position) and / or a mechanical transmission ratio, and / or a percentage of acceleration phase duration.

[0075] An algorithm for implementing such a function can also perform calculations of first-order (velocity), second-order (acceleration), and third-order derivatives of position. It may include:

[0076] - to limit the third-order derivative, in order to create trajectories with smooth accelerations and / or decelerations, instead of abrupt variations in acceleration and / or deceleration;

[0077] - and / or to include phases with a limited third-order derivative, for example constant;

[0078] - and / or to include phases with a zero third-order derivative (constant or zero acceleration or deceleration).

[0079] Based on an example with N=7, the following phases are planned:

[0080] Phase 1: constant (and positive) third-order derivative, the acceleration increases from 0 to a maximum value;

[0081] Phase 3: constant (and negative) third-order derivative, the acceleration decreases from the maximum value to 0;

[0082] Phase 5: constant (and negative) 3rd order derivative, deceleration increases (acceleration becomes negative);

[0083] Phase 7: constant (and positive) third-order derivative, the deceleration decreases to 0;

[0084] Phase 2: third-order derivative is zero, the acceleration is constant;

[0085] Phase 4: derivative of order 3 is zero, the speed is constant;

[0086] Phase 6: derivative of order 3 zero, the deceleration is constant; Position request information, which may be contained in a LIN Rx message, may form the input of a control cycle in means 64; in the case of a LIN message, this may be decoded at the level of a LIN message manager 65b and actions may be defined by means 78 (state machine, described below) before providing an input to means 64.

[0087] The circuit in Figure 1 incorporates overvoltage and reverse voltage protection means 55, these means being located outside the circuit. For example, a supply voltage between 9 V and 16 V can be applied. The VBATT voltage is, for example, approximately 40 V, but can be a different value depending on the user's requirements.

[0088] Alternatively, it is possible to implement 55a means integrated into the circuit to protect against overvoltages and reverse voltage. This is illustrated in Figure 2, the other elements of this figure being identical or similar to those of Figure 1.

[0089] A circuit according to the invention, for example according to one or the other of the variants of Figures 1 and 2, may implement one or more of the following means or functions: a filter 72 that filters the actuator step to prevent it from implementing a step smaller than a programmed minimum step and / or the noise of position requests (this noise may come, for example, from a user-side interface), which adds fluidity to the control operations; this ensures that a requested position is a valid position; for example: if the last commanded position was 20° and a new request arrives for a position of 20.1°, the entire control loop is not activated; this allows for energy savings and optimization of operations; and / or means 74 for implementing an unblocking function, which performs a sequence of vibrations to free the motor when it is blocked;and / or means 76 for implementing a self-learning function: this function, when implemented, allows the position of the output shaft to be scanned over its entire range of positions, in order to determine its stopping positions (for calibration purposes); and / or means 78 (a circuit or a chip) for implementing a state machine which controls the switching between different states of the circuit, for example between an initial calibration, a normal control state of the output shaft, which is for example linked to a component, for example a valve, and one or more motor stopping modes;Alternatively, or in addition, one or more (other) modes or states may be provided or are potentially possible, for example, an unlocking mode (see the unlocking function above), a self-learning mode (see the self-learning function above), a wait mode (or "standby", for example, waiting for a command), an error mode, an execution mode: means 78 allow the switching between the different possible states of the circuit to be controlled; and / or means 58a and / or 36a, of the "anti-windup" type, in filters 58 and / or 36; indeed, a PID loop can accumulate errors if the actuator is saturated. To avoid this situation, the speed control loop 20 and / or the current control loop 10 are used because these are internal and fast loops;This also provides additional control stability to the system because it allows for better handling of scenarios where saturation limits are frequently reached. This function prevents the accumulation of errors when the control output is saturated, thus eliminating any overshoot and / or slow response when returning to normal operation.

[0090] As mentioned above, the self-learning function scans the output shaft's position across its entire range to determine its stopping positions (for calibration purposes). The corresponding algorithm implements an automatic calibration function, for example, for a component such as a valve, which detects the actuator's mechanical stroke limits without manual configuration. Once triggered, it drives the motor in both directions until it reaches the physical stops, automatically recording the minimum and maximum positions, for example, of a valve (MVAS_Learn_Result_l\ / lin / l\ / lax). The mechanical limit position is determined by continuous current monitoring, and as soon as the mechanical stop is reached, a current spike is observed and compared to pre-recorded thresholds stored in the chip's memory.This eliminates the need for manual calibration during manufacturing or after component replacement: the system simply learns its own mechanical limits and stores them for subsequent position control operations. This type of algorithm offers plug-and-play functionality, reducing production lead times and maintenance complexity, while ensuring accurate position reference regardless of mechanical tolerances or wear.

[0091] The means (circuit or chip) 78 integrate the software functionalities of the state machine. Such a state machine, whether realized or implemented in hardware, offers superior deterministic and real-time state transitions compared to purely software implementations. The outputs of the means 72, 74, and 76 can form the required (or reference) input of the comparator 64, to which the detected position is compared.

[0092] Preferably, a circuit according to the invention also includes interface means 61 of type l 2 C, in order to configure the circuit, for example implemented in the form of an ASIC, and to program parameter values ​​in one or more memory areas.

[0093] A circuit according to the invention, for example according to one or the other of the variants of Figures 1 and 2, may implement one or more of the following means (or circuits) to implement one of the error detection(s): detection means 82 to implement detection of a motor blockage; these means detect that the motor is blocked based on the signals provided by the current, angular velocity, and angular position detection loops 10, 20, 30. and / or detection means 84 to implement detection of a rotation error; these means detect that the motor is blocked based on the signals provided by the angular velocity and angular position detection loops 20, 30; for example, a situation may arise in which there is a problem with the gear set that connects the motor rotor to the output shaft: in this case, the motor 24 can rotate but not the output shaft;This can be identified with means 84; a fault alert can be triggered, for example by the ECU of a vehicle that is equipped with a circuit according to the invention; and / or means 86 for detecting an overcurrent supplied by any one of the controllers 23i, 232, 23a; such an overcurrent can be detected, separately, for each of the 6 transistors that form the dividers 22i, 222, 22a; for example, an overcurrent can be detected as soon as one of the nodes MOUT1, MOUT2, MOUT3 is short-circuited to the positive or negative supply value of the transistors or to another of these nodes; practically, the dividers 22i, 222, 22a can be switched off as soon as overcurrent events are detected; and / or detection means 88 for implementing detection of the duration during which a requested position is reached; if this duration is greater than a predetermined duration, an error signal (called a slow response signal) may be emitted;and / or detection means 89 for implementing the detection of the position error of the actuator on which the component (for example, the valve) is fixed, i.e., the difference between the detected position and the requested position, both compared by the comparator 64; preferably, this position error remains below a pre-programmed limit; if this is not the case, the detection means 89 can emit an error signal; and / or temperature detection means 92 using one or more temperature sensor(s); for example, it is possible to implement temperature control mechanisms: one using a measuring resistor 93 external to the circuit, the other using a temperature sensor 94 integrated into the circuit; an analog-to-digital converter 98 can provide digital representations of output voltages which can be compared to programmed limit temperature values;means 99 can issue an alert if the temperature exceeds a certain threshold; one or more of these pieces of information can be sent to an ECU (an electronic control unit), for example, of a vehicle; more generally, a circuit according to the invention can operate in a very wide temperature range, for example, between -40°C and 125°C; and / or means 102 for detecting undervoltage; the supply voltage BVDD supplied to the motor 24 can be measured, for example, on a periodic basis, using the auxiliary converter 98: if the BVDD voltage is below a certain threshold, an undervoltage signal or message can be issued; and / or means 104 for detecting a supply voltage error, for example, for the supply voltages VDDA and / or VDDD and / or the voltage of (for example) 5V;if one of these voltages is detected as being less than a minimum value or greater than a maximum value, an error signal or message may be emitted; and / or means 106 for detecting an overvoltage supply; for example, a circuit, for example again an analog circuit, allows comparing, preferably continuously or asynchronously, the BVDD supply voltage supplied to the motor 24; if this voltage exceeds a maximum value, an overvoltage signal or message may be emitted; and / or means 108 forming a clock, to detect if a preprogrammed time is exceeded, for example between the reception of instructions and / or data and / or frames (LIN frames) of successive instructions on the interface 65; and / or means 112 for detecting an overcurrent supplied to the motor 24 (for example according to parameters specific to it): for example again, the measured current is compared with a pre-established limit;If this limit is exceeded, an overcurrent signal or message may be emitted; it should be noted that the means 86 make it possible to protect the transistors which form the dividers 22i, 222, 22a during overcurrent events and to avoid certain failures; and / or means 114 for error detection of the oscillators 116, 118; for example the detection may relate to the ratio between the high and low oscillation frequencies; if this ratio is not in a predetermined range, an oscillator error signal or message may be emitted; and / or means 65a, respectively 65b, for interfacing, respectively for processing the messages received at input 65.

[0094] A circuit according to the invention can be implemented in the form of an ASIC. The interface 65 allows the circuit to be connected to the control system or to an electronic control unit (ECU), for example in a motor vehicle.

[0095] According to an example embodiment, one or more of the means 23i, 232, 233, 321, 52, 53, 56, 59, 65, 86, 94, 96, 98, 118 can be implemented in analog form. The other components are preferably implemented in digital form.

[0096] Figure 3 shows a control circuit 110 that controls an electric motor coupled to a gear train 112, which can be connected to a valve to actuate it. Advantageously, the control circuit 110 is replaced by a circuit 100 according to the invention, preferably in the form of an ASIC.

[0097] A circuit according to the invention is particularly well-suited for controlling a motor 24 that actuates a moving part 120 (Figure 4), for example, a valve, in the automotive field. Such a part, for example, such a valve, can be implemented in a fluidic or hydraulic circuit 130 of a motor vehicle. Transmission elements such as the gear train 112 (as illustrated in Figure 3) can couple the motor 24 and the valve or the part 120.

[0098] The invention saves space by integrating components typically found on a PCB into an ASIC. A circuit according to the invention may include one or more memory areas for storing one or more of the data discussed in this application.

[0099] A circuit according to the invention offers several advantages over current valve control circuits and methods using an actuator; in particular, since all circuit elements are integrated into a custom chip, it is less expensive, lighter, faster, more energy-efficient, and easier to mass-produce. Its implementation eliminates many intermediate steps in the supply chain and also reduces environmental waste. Furthermore, parallel processing allows for better position control of an actuator valve and makes it more responsive to motor commands.

Claims

DEMANDS 1. Control circuit (100, 100') for an electric actuator comprising an electric motor (24) having a plurality of windings and an output shaft, this circuit comprising: means (22i, 222, 22a, 23i, 232, 23a, 52, 54, 55) for supplying voltage to each winding of the motor and a first loop (10) for controlling at least one current supplied to the windings of the motor; a second loop (20) for controlling the angular speed of the motor, the output of this loop forming an input to the loop (10) for controlling at least one current supplied to the windings of the motor; a third loop (30) for controlling the position of the output shaft, the output of this loop (30) forming an input to the loop (20) for controlling the angular speed of the motor;the first control loop (10) comprising means (26) for measuring said current, the measured current being compared to the output of the second control loop (20), the first control loop (10) further comprising means for dividing the result of said comparison by a supply voltage (BVDD) of the means (22i, 222, 22a, 23i, 232, 23a, 52, 54, 55) for supplying voltage to said plurality of motor windings.; 2. Circuit according to claim 1, the means (22i, 222, 22a, 23i, 232, 23a, 52, 54, 55) for supplying each winding of said plurality of windings of the motor comprising a controller (23i, 232, 23a) and a half-bridge (22i, 22a, 22a).

3. Circuit according to claim 2, the controller (23i, 23a, 23a) being of the "Break-Before-Make driver" type, or without overlap or non-short-circuiting or of the "Break-Before-Make" type.

4. Circuit according to any one of claims 1 to 3, the second loop (20) comprising means (26) for estimating an angular velocity on the basis of the time elapsed between changes in position of the rotor relative to the stator.

5. Circuit according to claim 4, the second loop (20) comprising means (63) for comparing the detected angular velocity to a setpoint (62) of angular velocity.

6. Circuit according to any one of claims 1 to 5, the third loop (30) comprising at least one sensor (62) for measuring the position of the output shaft, a position thus detected being provided to an input of a comparator (64) for comparison with a requested position, the difference in output forming an input for the second loop (20).

7. Circuit according to claim 6, the third loop (30) comprising means (66) forming a multiplier of the difference at the output of said comparator.

8. Circuit according to any one of claims 1 to 7, the third loop (30) comprising means (66) implementing a dynamic velocity profile generator function based on the error difference between a requested position and an actual position.

9. Circuit according to any one of claims 1 to 8, comprising means (82) for detecting a motor blockage, based on the signals provided by the first loop (10), the second loop (20) and the third loop (30).

10. Circuit according to claim 9, comprising means (74) for implementing a motor unlocking function when the motor is blocked.

11. Circuit according to any one of claims 1 to 10, comprising means (76) for implementing a self-learning function, for determining the stopping positions of the motor output shaft.

12. Circuit according to any one of claims 1 to 11, comprising means (78) for implementing a state machine which controls the switching between different states of the circuit, for example between a calibration state, an output shaft control state, and one or more motor stop mode(s).

13. Circuit according to any one of claims 1 to 12, comprising means (72) for filtering the step of the actuator and for preventing it from implementing a step less than a programmed minimum step.

14. Circuit according to any one of claims 10 to 13, the output of at least one of the means (72) for filtering the step of the actuator and / or of the means (74) for implementing an unlocking function, and / or of the means (76) for implementing a self-learning function forming a reference input of a comparator (64) of the third loop (30), to which a detected position is compared.

15. Circuit according to any one of claims 1 to 14, comprising means (54, 55) for supplying voltage, of the charge pump type.

16. Circuit according to any one of claims 1 to 15, comprising means (86) for detecting an overcurrent supplied to at least one of the windings of the motor (24).

17. Circuit according to any one of claims 1 to 16, comprising means (102, 104, 106) for detecting over-voltage, under-voltage, or voltage supply error.

18. Circuit according to any one of claims 1 to 17, comprising means (84) for detecting an error in the rotation of the motor (24) and / or means (89) for detecting an error in position.

19. Circuit according to any one of claims 1 to 18, comprising interface means (61), for example of type l 2 C, in order to configure and / or program the circuit.

20. Circuit according to any one of claims 1 to 19, comprising means (65) for interfacing with a local network and / or an electronic control unit (ECU).

21. Circuit according to any one of claims 1 to 20, further comprising means (55) for supplying voltage to the circuit.

22. Circuit according to any one of claims 1 to 21, the first control loop (10) comprising pulse width modulator means (38), division by said supply voltage (BVDD) being carried out before pulse width modulation.

23. Circuit according to any one of claims 1 to 22, comprising means for implementing one or more overvoltage protection functions and / or reverse polarity protection functions and / or one or more filtering(s) of a supply voltage of the circuit, can be applied to this supply voltage of the circuit, the supply voltage (BVDD) of the means (22i, 222, 22a, 23i, 232, 23a, 52, 54, 55) of supplying voltage to said plurality of motor windings being that obtained after said one or more functions.

24. Control system for a moving part, comprising an electric motor (24) having a plurality of windings and an output shaft for actuating said moving part, and a control circuit (100, 100') according to any one of claims 1 to 22, of the electric motor (24) 25. Moving part, for example a valve, of a fluidic or hydraulic circuit, comprising a control system according to claim 24.

26. Fluidic or hydraulic circuit, comprising at least one moving control part according to claim 25.

27. Motor vehicle comprising a fluidic or hydraulic circuit according to claim 26.

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