METHOD FOR MONITORING THE ROTOR ANGLE OF AN ELECTRIC MACHINE OF AN ELECTRIC OR HYBRID MOTOR VEHICLE

Abstract

The invention relates to a method for monitoring the rotor angle of an electric motor vehicle's electric motor. The method comprises a resolver that acquires first and second voltages (Ucos; Usin) proportional to the cosine and sine of the angle. A control unit calculates the sum (USumSquare) of the squares of said first and second voltages (Ucos; Usin) and compares this sum to predetermined lower and upper acceptability thresholds (Saccmini; Saccmaxi). The unit then issues an alarm signal to the user and / or a shutdown command for the electric motor if said sum falls outside the lower and upper acceptability thresholds, or allows the electric motor to continue operating if it falls within the threshold values. The invention relates to an electric or hybrid vehicle comprising hardware and software means for performing these calculations and threshold comparison tests. Figure 1

Description

Title of the invention: METHOD FOR MONITORING THE ROTOR ANGLE OF AN ELECTRIC MACHINE OF AN ELECTRIC OR HYBRID MOTOR VEHICLE

[0001] The invention relates to a method for monitoring the angle of the rotor of an electric machine comprising an electric or hybrid motor vehicle comprising a powertrain control unit and an electric motor control unit, said electric machine being equipped with a sine / cosine rotation sensor arranged to determine the angular position of said rotor.

[0002] The invention further relates to an electric or hybrid motor vehicle comprising monitoring means arranged for monitoring the angle of the rotor of an electric machine, which is included in said vehicle, according to this method.

[0003] The invention relates to the field of monitoring the proper functioning of the angular position sensor of the rotor of electric machines of electric or hybrid vehicles.

[0004] A sinus-cosine rotation sensor, such as a resolver, makes it possible to determine the angular position of the rotor of an electric motor.

[0005] Information regarding the position of the electric machine's rotor is crucial, as it enables the calculation of the torque produced by the electric machine. Therefore, if the angular position sensor of the electric machine's rotor malfunctions, the measurement of the torque produced by the electric machine is inaccurate, and consequently, the electric machine's control system malfunctions. This creates a risk of the electric machine becoming uncontrolled, and thus a risk of accidents for the vehicle user and the surrounding environment. This context is therefore critical, as it directly impacts the safety of electric and hybrid vehicles.

[0006] Determining the rotor position can be subject to error due to static and / or dynamic deviations. Static deviations in the signal angle depend on the manufacturing tolerances of the sensors and the tolerances of components in signal processing and analog-to-digital conversion. Dynamic deviations exist and occur during operation in the event of mechanical malfunctions of the stator and / or rotor, environmental influences, particularly those related to temperature, and may be related to the aging of the electronics. Consequently, measurement deviations may occur in determining the angle, rotational speed, and acceleration.

[0007] It is therefore important to have means to determine these static and dynamic deviations, to diagnose them in order to effectively control the electrical machine carrying such a sine / cosine rotation sensor.

[0008] Document WO201872778_Al describes the use of a sinusoidal-cosine rotation sensor, such as a resolver, and a dynamic correction method in addition to static correction, to correct measurement errors of the sensor. This method combines dynamic and static correction to compensate for amplitude and offset deviations, thereby increasing the accuracy of the measurements. The dynamic correction is performed online, while the static correction uses a pre-established lookup table.

[0009] This document describes a method for linearizing the sine / cosine signal from the rotor speed sensor by applying least-squares signal reconstruction to obtain a clean signal. This eliminates signal defects, thus improving the rotor speed reading. While this processing does allow for the recovery of a clean, post-processed signal for the rotor speed, it makes it impossible to diagnose a fault in the engine speed sensor: the sensor faults are corrected without the ability to diagnose them; it is therefore possible to recover an incorrect signal without being able to identify that the measured signal is faulty.

[0010] This method allows for the simultaneous compensation of static and dynamic deviations in order to improve measurement accuracy. One of its drawbacks is the use of significant computing resources, as a very high sampling frequency is required, and the least-squares method program must run very quickly for torque control of the machine. Therefore, a very large central processing unit (CPU), as well as the associated inverter, is necessary to linearize the signal.

[0011] This prior art therefore constitutes primarily a means of improving the quality of the rotor speed signal.

[0012] However, this method does not attempt to diagnose deviations in dynamic signals (particularly in cases of obsolescence or wear of the resolver sensor), but rather to compensate for them. The risk is therefore of obtaining a false but clean signal, without being able to detect the error in the signal, and without being able to control the electrical machine, thus jeopardizing user safety.

[0013] However, this prior art only verifies that these voltages are within an acceptable range, but does not verify the plausibility of the cosine and sine values ​​for the same rotor angle.

[0014] Currently, for monitoring the proper functioning of the angular position sensor of the rotor of an electric machine of an electric or hybrid vehicle, one only verifies that the information returned by the rotor angular position sensor gives a cosine value of the angle within a defined range, and a sine value of the angle within an equally defined range.

[0015] However, it is observed that the angular position sensor of the rotor of such an electric machine can return both information of the cosine of the rotor angle and information of the sine of the rotor angle, which are each well within the defined range, but with a risk of inconsistency between the sine and the cosine, such a situation then reflecting a malfunction of the angular position sensor of the rotor of an electric or hybrid vehicle.

[0016] The objective of the present invention is to overcome these drawbacks by providing monitoring of the proper functioning of the rotor resolver, by examining the raw signal from the sensor, in order to identify any fault in the resolver sensor. The invention uses the raw signal to diagnose the plausibility of the sine / cosine signal from the resolver, in particular by verifying, for any angle, the formula "sin² + cos² = 1".

[0017] The invention thus aims to improve the monitoring function of the proper functioning of the angular position sensor of the rotor of an electric machine of an electric or hybrid vehicle.

[0018] The invention consists of adding a test on the angle sine and angle cosine signals returned by the angular position sensor of the rotor of an electric machine, to verify the relevance between the sine and cosine information returned by the sensor.

[0019] The checks known in the prior art, with a first range of values ​​for the sine of the rotor angle, and a second range of values ​​for the cosine of the rotor angle, are completed by the check that the total (sin2+cos2) of the rotor angle is within a third predetermined range of values.

[0020] To achieve this objective, the invention proposes a method for monitoring the angle of the rotor of an electric machine comprising an electric or hybrid motor vehicle comprising a powertrain control unit and an electric motor control unit, said electric machine being equipped with a sine / cosine rotation sensor arranged to determine the angular position of said rotor.

[0021] According to the invention, in a first step the variation of the efficiency coefficient of said electric machine is measured on a test bench, for each speed step, for each torque step, for each voltage step, for each supply current step and for each stator temperature step, said efficiency coefficient being the ratio between the mechanical power transmitted at the output of said electric machine to the traction chain of said motor vehicle and the power electrical input to said electric machine, said measurement being translated into a map of values ​​of said efficiency coefficient which is stored in a memory contained in said control unit of the electric motor, in a second step a first voltage proportional to the cosine of the rotor angle and a second voltage proportional to the sine of the rotor angle are collected by said sine / cosine rotation sensor, and are compared to a minimum voltage value and a maximum voltage value, in a third step a first test determines whether said first voltage and said second voltage are each within the range whose limits are said minimum voltage value and said maximum voltage value,and an alarm signal to the user and / or a stop command for said electric machine is issued by said powertrain control unit if said first voltage and / or said second voltage is outside said range, and, if said first voltage and said second voltage are each within said range, in a fourth step said electric motor control unit calculates the sum of the squares of said first voltage and second voltage, in a fifth step a second test compares said sum to a predetermined first lower acceptability threshold and second upper acceptability threshold, and an alarm signal to the user and / or a stop command for said electric machine is issued by said powertrain control unit if said sum is below said first lower acceptability threshold or above said second upper acceptability threshold,or said powertrain control unit authorizes the continued operation of said electrical machine if said sum is between said first lower acceptability threshold and said second upper acceptability threshold.

[0022] Thus the invention guarantees that the two voltage measurements are carried out on the same value of rotor angle.

[0023] Advantageously, the values ​​of said first lower acceptability threshold and of said second upper acceptability threshold are calibrated during the selection of said sinus / cosine rotation sensor and of said first step, during which a function for monitoring the proper functioning of said sinus-cosine rotation sensor is developed.

[0024] Thus this rotation sensor is calibrated beforehand, according to predetermined threshold values.

[0025] Advantageously, if, in said fifth step, said electric motor control unit determines that said sum is less than said first lower acceptability threshold or greater than said second upper acceptability threshold, in a sixth step a transitional time is measured during which said sum exceeds said second upper acceptability threshold or during which said sum falls below said first lower acceptability threshold, and, if said transient duration is greater than respectively a first predetermined duration D, or a second predetermined duration D, an alarm signal to the user and / or a stop order for said electrical machine is issued by said powertrain control unit.

[0026] It is thus possible to manage the operation of the electrical machine without disturbance by an instantaneous parasite, by checking the operation over a certain period of time.

[0027] Advantageously, said first predetermined duration and said second predetermined duration are calibrated during said first step, and during the development phase of said function for monitoring the proper functioning of said sensor of said sinus-cosine rotation, and said first predetermined duration and said second predetermined duration are chosen between 80 ms and 120 ms.

[0028] The conditions for acceptance or refusal are thus perfectly defined

[0029] Advantageously, if said transient duration is greater than respectively said first predetermined duration, or said second predetermined duration, in a seventh step said electric motor control unit engages a reconfiguration strategy during which said electric motor control unit stores a fault code in its read-only memory and communicates it to said powertrain control unit, to indicate to the after-sales service that said electric motor control unit has encountered a problem on said sine / cosine rotation sensor and / or on said electric machine,and during which said electric motor control unit requests said powertrain control unit to illuminate a STOP indicator on the instrument panel of said vehicle and / or to display a message on said instrument panel to inform the user of said vehicle of a problem with the powertrain.

[0030] The after-sales service is thus exactly informed about the occurrence of incidents concerning the operation of the electrical machine.

[0031] Advantageously, during said seventh step, said electric motor control unit commands the cessation of operation of said electric machine, including the memorization of a fault code, the lighting of a STOP light and the stopping of the electric machine.

[0032] Such a safety stop helps to preserve the vehicle.

[0033] Advantageously, if said transitional period is greater than said first predetermined period, or said second predetermined period respectively, in an eighth step said vehicle is subject to a recovery strategy implemented by the after-sales service, during which the read-only memory of said electric motor control unit is erased and reconditioned, and during which said sine / cosine rotation sensor and said electrical machine are checked and / or exchanged.

[0034] The vehicle can then leave the after-sales service perfectly reconditioned and in complete safety.

[0035] Advantageously, if after a stop of said electric machine commanded by said powertrain control unit, and if after re-ignition the fault is re-established, said electric motor control unit stops requesting the illumination of a STOP light and the emission of a message to the dashboard of said vehicle, then said electric motor control unit re-authorizes the operation of said electric machine.

[0036] Thus a fault identified as transient and random does not disrupt the proper functioning of the electrical machine.

[0037] Advantageously, said sine / cosine rotation sensor is a resolver.

[0038] A resolver is a component produced in large quantities, with high reliability, and a reasonable cost.

[0039] The invention further relates to a motor vehicle comprising at least one electric machine, a powertrain, a powertrain control unit, an electric motor control unit for each said electric machine, each said electric machine being equipped with a sine / cosine rotation sensor or a resolver arranged to determine the angular position of said rotor.

[0040] According to the invention, said powertrain control unit and / or at least one said electric motor control unit comprises hardware means for calculation and software means for implementing this method, comprises means for transmission with an external database comprising predetermined threshold values ​​of various parameters, and / or means for transmission with a test bench performing a mapping of the values ​​of an efficiency coefficient which is the ratio between the mechanical power transmitted at the output of said electric machine to the traction chain of said motor vehicle and the electrical power at the input of said electric machine, comprises a memory for storing said mapping,includes means for measuring and collecting, by said sine / cosine rotation sensor or said resolver, a first voltage proportional to the cosine of the rotor angle and a second voltage proportional to the sine of the rotor angle; includes means for comparing said first voltage and said second voltage to a predetermined minimum voltage value and a predetermined maximum voltage value; includes means for calculating a sum of the squares of said first and second voltages; includes means for comparing said sum to, a first lower acceptability threshold and a second upper predetermined acceptability threshold, and includes means for generating an alarm signal to the user and / or an order to stop said electrical machine in the event of exceeding predetermined value thresholds for said first voltage, said second voltage, and said sum, and includes a fault memory to inform after-sales.

[0041] The vehicle thus includes all the means to control each electrical machine it contains.

[0042] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.1] illustrates the successive steps of the process according to the invention; - [Fig.2] illustrates a unit circle with a cosine axis and an axis sines, an oriented angle extending between the cosine axis and a radial from the center of the unit circle, and the values ​​of the cosine of this angle and the sine of this angle; - [Fig.3] schematically illustrates an electric motor vehicle or hybrid, comprising at least one electric machine, and equipped to implement the process according to the invention.

[0043] The invention relates to a method for monitoring the angle A of the rotor 1 of an electric machine 2 comprising an electric or hybrid motor vehicle 100 comprising a powertrain 9, a powertrain control unit 4, and at least one electric motor control unit 3, the electric machine 2 being equipped with a sine / cosine rotation sensor 5 arranged to determine the angular position of this rotor 1. The powertrain control unit 4, and each electric motor control unit 3, together constitute monitoring means 100, which are arranged for monitoring the angular position of the rotor 1 of each electric machine 2, comprising this vehicle 1000.

[0044] The invention relates to the creation of a monitoring function for information on the angle A of the rotor 1 of an electric machine 2, in particular of an electric machine 2 comprising an electric or hybrid motor vehicle 100.

[0045] The invention consists of using a rotor angular position sensor, in particular a sine / cosine rotation sensor 5, including a resolver, to measure the angle A of the rotor 1. The resolver 5 returns two pieces of information, the cosine and sine of the angle A of the rotor 1, which are translated into voltages. The prior art only verified that these voltages were within an acceptable range, but did not verify the plausibility of the cosine and sine values. The invention introduces a formula Mathematics is used to verify the consistency between these values. Operation is monitored by comparing the sum of the squares of the cosine and sine voltages to acceptable thresholds. If these thresholds are exceeded for a specified duration, a reconfiguration strategy is initiated, including storing a fault code, illuminating a STOP indicator, and shutting down the electrical machine.

[0046] Various computers are involved in controlling the vehicle.

[0047] The electric machine computer, or electric motor control unit 4, is called MCU (from the English "motor control unit"), and manages the control of the electric machine 2.

[0048] The powertrain supervisor (or PMS) is called the powertrain control unit 3 of the electric vehicle 100, abbreviated as eVCU (electric vehicle control unit), and coordinates, controls, commands, and supervises the various computers communicating via CAN bus-type data and information communication means (eCAN bus). These computers include, in particular, the OBCDC current converter control means, the electric motor control unit (MCU), the vehicle parking lock actuator management unit abbreviated as ePLU, and the battery management system (BMS).

[0049] The control means of the OBCDC current converter include the computer which handles the management of the vehicle's OBC (on-board charger), and the AC / DC (alternating current / direct current) part of the current converter.

[0050] A permanent magnet synchronous electric motor operates using pulses, which are generated by coils positioned radially on either side of the stator, relative to the motor axis. The permanent magnet rotor rotates around the motor axis and has a positive and a negative pole on either side of this axis. When current flows through a coil, it acts as an electromagnet, the orientation of whose poles depends on the direction of the current. Each phase can therefore have its positive or negative pole facing the axis, depending on whether the rotor is to be pushed or pulled (depending on its position, the positive or negative pole will be activated). The rotor is driven by a succession of alternating current commutations of the coils (fluctuation of positive / negative polarities) in order to impart pulses to the rotor, which is sensitive to the magnetic force, since this rotor is a permanent magnet.

[0051] A bidirectional motor speed sensor is installed at the output of the electric machine (generally capable of rotating in both directions). Very often the Reverse gear in an electric or hybrid vehicle is not achieved by changing a set of gears in a gearbox, but by reversing the direction of rotation of the electric motor, which in turn reverses the direction of rotation of the vehicle's wheels. It is solely thanks to this bidirectional speed sensor that the electric motor control unit (MCU) and / or the powertrain control unit (eVCU) determines the torque output of the electric motor.

[0052] The electric machine receives electrical power at its input terminals from the vehicle's high voltage (HV) circuit: Pélec = U x I, with Pélec = electrical power at the input of the electric machine, U = voltage across the terminals of the electric machine at the output of the HV circuit, I = current across the terminals of the electric machine at the output of the HV circuit.

[0053] This high voltage HV circuit is a current power supply circuit under a voltage generally between 350 V and 450 V.

[0054] The electric machine provides mechanical power to the vehicle's traction chain: Pmeca = C x co, with Pmeca = mechanical power output of the electric machine, C = torque output of the electric machine, co = rotation speed of the electric machine's rotor.

[0055] We call p the efficiency coefficient of the electrical machine which is measured on the bench for each step of speed, of torque, for each step of voltage, for each step of supply current and for each step of stator temperature.

[0056] The mapping of p values ​​is learned on the test bench of the electrical machine component and stored in the memory of the motor control unit MCU.

[0057] Thus Pméca = Pélec x p.

[0058] Therefore Cxm = UxIxp, therefore C = UxIxp / co.

[0059] So the motor control unit MCU measures or receives information about the voltage across the terminals of the electric machine.

[0060] The motor control unit MCU measures or receives information about the current drawn by the electric machine.

[0061] The motor control unit MCU measures or receives information on the rotational speed of the electric machine's rotor.

[0062] The motor control unit (MCU) deduces the efficiency coefficient by determining the rotor speed of the machine, the stator temperature, the current drawn by the electric machine, and the voltage across the electric machine terminals. Thus, the motor control unit (MCU) calculates the torque that the electric machine delivers to the traction chain using the formula: C = U x I x p / co.

[0063] The angular position sensor of the rotor of electrical machines is also called a resolver. This resolver is a sensor that measures the angular position of the rotor. The resolver returns two pieces of information to define this angle: it returns the cosine value of the rotor angle, and it returns the sine value of the rotor angle. Thus, with these two values, the rotor angle is clearly defined.

[0064] Of course, the sensor does not return a sine and a cosine value, but rather two voltages, which must be converted by a transformation matrix into a cosine and a sine value. The cosine of an angle is between -1 and +1 (the same applies to the sine). The resolver returns a voltage, which must be within a voltage range of InfV ​​to SupV, in particular, but not limited to, the voltage range of 0.3 V to 4.7 V for common resolver models used on electric motors in electric or hybrid vehicles, and each voltage corresponds to a cosine value between -1 and +1 (the same applies to the sine of the rotor angle).

[0065] The prior art consisted only of verifying, on the one hand, that the cosine information returned by the resolver was indeed in the voltage range InfV ​​to SupV, and that the sine information returned by the resolver was indeed in the voltage range InfV ​​to SupV, but no verification made it possible to establish that the value of the returned sine was plausible in relation to the value of the returned cosine.

[0066] The invention uses a simple trigonometric property, which is very easy to verify quickly by a calculator: a formula using cosine and sine is used to verify that the angle of the sine is indeed equivalent to the angle of the cosine. Indeed, for a given angle [3: sin2 [3 x + cos2 [3=1.

[0067] The invention uses this mathematical principle to verify the plausibility of the sine and cosine information returned by the resolver.

[0068] Indeed, if the resolver works correctly for any angle [3 of the rotor, the sine [3 returned by the resolver will be judged good, if the value of cosine [3 returned at the same instant by the resolver of the machine allows to satisfy to within a precision the formula: sin2 [3 + cos2 [3=1.

[0069] The invention retains the prior art test, which consists of verifying that the cosine information returned by the resolver is indeed in the voltage range InfV ​​to SupV, and that the sine information returned by the resolver is indeed in the voltage range InfV ​​to SupV.

[0070] More particularly InfV ​​= 0.3 V, and SupV = 4.7 V, in the most general case.

[0071] The InfV ​​and SupV values ​​are calibrated when the resolver is selected and therefore when the development phase of the function to monitor the proper functioning of the resolver.

[0072] The invention adds a new test: the resolver returns a voltage Usin for the value of sine, and a voltage Ucos for the value of cosine.

[0073] The MCU control computer of the electric machine performs the calculation: Usin x Usin + Ucos x Ucos = USumSquare, to determine this value USumSquare which represents the sum of the squares of the two received voltage values.

[0074] And this result USumSquare must be between a lower acceptability threshold Saccmini and an upper acceptability threshold Saccmaxi.

[0075] Naturally these two acceptability thresholds mini Saccmini and maxi Saccmaxi also depend on the type of resolver used.

[0076] The Saccmini and Saccmaxi values ​​are calibrated during the selection of the resolver, and during the development phase of the function for monitoring the proper functioning of the resolver.

[0077] In a particular and non-limiting example, these two thresholds are calibrated to the following values: Saccmini = 0.75 V, and Saccmaxi = 2.25 V, to take into account the possible measurement dispersions of the resolver.

[0078] Therefore, if the MCU controlling the electric machine finds that the value USumSquare exceeds the maximum acceptability threshold Saccmaxi for more than a first duration D1, or that the value USumSquare falls below the minimum acceptability threshold Saccmini for more than a second duration D2, the MCU controlling the electric machine engages a reconfiguration strategy.

[0079] The first and second durations D1, D2, are each calibrable during the development phase of the function monitoring the proper functioning of the resolver. More specifically, the first calibrable duration D1 is chosen between 80 ms and 120 ms, more specifically between 90 ms and 110 ms, and more specifically still close to 100 ms. Similarly, more specifically, the second calibrable duration D2 is chosen between 80 ms and 120 ms, more specifically between 90 ms and 110 ms, and more specifically still close to 100 ms.

[0080] With regard to the reconfiguration strategy put in place in the event of a prolonged exceedance of one of the acceptability thresholds, the reconfiguration consists of a succession of steps.

[0081] The electric machine control MCU stores a fault code in its read-only memory and communicates it to the eVCU control unit, to indicate to the after-sales service that the electric machine control MCU has encountered a problem resolving the electric motor

[0082] The electric machine control MCU requests the eVCU control unit to illuminate a STOP light on the instrument panel and a message on the instrument panel to indicate to vehicle users that a problem has occurred on the drive chain.

[0083] The MCU control unit of the electric machine stops the operation of the electric machine.

[0084] With regard to recovery, a test campaign has shown that the severity of a malfunction of the resolver is often so serious that, in a preferred variant, recovery can only be achieved by erasing the read-only memory of the MCU controlling the electric machine by the after-sales teams and checking the electric machine (or even changing the resolver or the electric machine by the after-sales teams).

[0085] However, another variant can be considered whereby, upon switching off the ignition, the fault is cleared, and the vehicle is allowed to restart once the fault has been cleared. That is to say, the MCU controlling the electric motor stops requesting the STOP warning light and a message on the instrument panel, and then the MCU controlling the electric motor reauthorizes the operation of the electric motor. The only remaining consequence of this reconfiguration mode is that the fault code remains stored in the ROM memory of the eVCU control unit and the MCU controlling the electric motor, so that after-sales service can see that the electric motor has experienced an excessive temperature gradient in the stator.However, this fault code does not remain in a "permanent" state in the memory of the MCU (electric machine control unit) and the eVCU (electronic vehicle control unit), but rather the fault code switches to a "transient" state to indicate to the after-sales service that the fault has resolved itself.

[0086] More particularly, in an advantageous embodiment, the method according to the invention is applied to monitoring the angle of the rotor 1 of an electric machine 2 comprising an electric or hybrid motor vehicle 100 comprising a powertrain control unit 3 and an electric motor control unit 4, the electric machine 2 being equipped with a sine / cosine rotation sensor 5 arranged to determine the angular position of the rotor 1.

[0087] According to the invention, in a first step 10 the variation of the efficiency coefficient p of the electric machine 2 is measured on a test bench, not illustrated, for each speed step, for each torque step, for each voltage step, for each supply current step and for each stator temperature step, the efficiency coefficient p being the ratio Pélec / Pméca between the mechanical power Pméca transmitted at the output of the electric machine 2 to the traction chain of the motor vehicle 100 and the electrical power Pélec at the input of the electric machine 2, the measurement being translated into a map of the values ​​of the efficiency coefficient p which is stored in a memory which includes the control unit of the electric motor 4.

[0088] In a second step 20 a first voltage Ucos proportional to the cosine of the angle A of the rotor and a second voltage Usin proportional to the sine of the angle A of the rotor 1 are collected by the sine / cosine rotation sensor 5, are compared to a minimum voltage value InfV ​​and to a maximum voltage value SupV.

[0089] In a third step 30 a first test determines whether the first voltage Ucos and the second voltage Usin are each within the range whose terminals are the minimum voltage value InfV ​​and the maximum voltage value SupV, and an alarm signal to the user and / or a stop order for the electric machine 2 is issued by the powertrain control unit 3 if the first voltage Ucos and / or the second voltage Usin is outside the range.

[0090] The stopping of the electric machine 2 means that it is no longer powered, and that it is therefore in freewheeling mode.

[0091] And, if the first voltage Ucos and the second voltage Usin are each in the range in a fourth step 40 the electric motor control unit 4 calculates the sum USumSquare of the squares of the first voltage Ucos and second voltage Usin.

[0092] In a fifth step 50 a second test compares the sum USumSquare to a first lower acceptability threshold Saccmini and to a second upper acceptability threshold Saccmaxi predetermined, and an alarm signal to the user and / or a stop order of the electric machine 2 is issued by the powertrain computer control unit 3 if the sum USumSquare is less than said first lower acceptability threshold Saccmini or greater than said second upper acceptability threshold Saccmaxi, or the powertrain computer control unit 3 allows the continued operation of the electric machine 2 if the sum USumSquare is between the first lower acceptability threshold Saccmini and the second upper acceptability threshold Saccmaxi.

[0093] In particular, the values ​​of the first lower acceptability threshold Saccmini and the second upper acceptability threshold Saccmaxi are calibrated during the selection of the sine / cosine 5 rotation sensor and the first step 10, during which a function for monitoring the proper functioning of the sine / cosine 5 rotation sensor is developed.

[0094] More specifically, if, in the fifth step 50, the control unit of the electric motor 4 determines that the sum USumSquare is less than the first lower acceptability threshold Saccmini or greater than the second upper acceptability threshold Saccmaxi, in a sixth step 60, a transient duration is measured during which the sum USumSquare exceeds the second upper acceptability threshold Saccmaxi or during which the sum USumSquare falls below the first lower acceptability threshold Saccmini, and, if the transient duration is greater than respectively a first predetermined duration DI, or a second predetermined duration D2, an alarm signal to the user and / or a stop order for the electric machine 2 is issued by the control unit of the powertrain computers 3.

[0095] In particular, the first predetermined duration DI and the second predetermined duration D2 are calibrated during the first step 10, and during the development phase of the function monitoring the proper functioning of the sine / cosine rotation sensor 5, and the first predetermined duration DI and the second predetermined duration D2 are chosen between 80 ms and 120 ms.

[0096] In one variant, it is possible to provide a degraded operating period to allow the user to bring their vehicle to a safe position, where it does not pose a danger to other road users or its occupants. For example, and without limitation, a reduction in machine torque to 25% of the maximum torque can be provided for a safety period of approximately ten seconds, or another duration, before the vehicle engages neutral.

[0097] More specifically, if the transient duration is greater than respectively the first predetermined duration DI, or the second predetermined duration D2, in a seventh step 70 the electric motor control unit 4 engages a reconfiguration strategy during which the electric motor control unit 4 stores a fault code in its read-only memory and communicates it to the powertrain control unit 3, to indicate to the after-sales that the electric motor control unit 4 has encountered a problem on the sine / cosine rotation sensor 5 and / or on the electric machine 2, and during which the electric motor control unit 4 requests the powertrain control unit 3 to illuminate a STOP light on the vehicle's dashboard 100 and / or to issue a message to said dashboard to indicate to the user of the vehicle 100 the occurrence of a problem on the powertrain.

[0098] More specifically, during the seventh step 70, the electric motor control unit 4 commands the shutdown of the electric machine 2, including the storage of a fault code, the lighting of a STOP light and the shutdown of the electric machine.

[0099] More particularly, if the transient duration is greater than respectively the first predetermined duration DI, or the second predetermined duration D2, in an eighth step 80 the vehicle 100 is subject to a recovery strategy implemented by the after-sales, during which the read-only memory of the electric motor control unit 4 is erased and reconditioned, and during which the sine / cosine rotation sensor 5 and the electric machine 2 are checked and / or exchanged.

[0100] In particular, if after a stop of the electric machine 2 commanded by the control unit of the powertrain computers 3, and after re-ignition the fault is re-established, the control unit of the electric motor 4 stops requesting the illumination of a STOP light and the emission of a message to the instrument panel of the vehicle 100, then the control unit of the electric motor 4 re-authorizes the operation of the electric machine 2.

[0101] More specifically, the sine / cosine rotation sensor 5 is a resolver.

[0102] The invention also relates to a motor vehicle 100 comprising at an electric machine 2, a powertrain 9, a powertrain computer control unit 3, an electric motor control unit 4 for each electric machine 2, each electric machine 2 being equipped with a sine / cosine rotation sensor 5 or a resolver arranged to determine the angular position of the rotor 1.

[0103] According to the invention, the control unit of the powertrain computers 3 and / or at least one said control unit of the electric motor 4 comprises hardware means for calculation and software means for implementing this method, comprises means for transmission with an external database comprising predetermined threshold values ​​of various parameters, and / or means for transmission with a test bench performing a mapping of the values ​​of an efficiency coefficient p which is the ratio Pélec / Pméca between the mechanical power Pméca transmitted at the output of the electric machine 2 to the traction chain of the motor vehicle 100 and the electrical power Pélec at the input of the electric machine 2, comprises a memory for storing such a mapping,includes means for measuring and collecting, by the sine / cosine rotation sensor 5 or the resolver, a first voltage Ucos proportional to the cosine of the angle A of the rotor and a second voltage Usin proportional to the sine of the angle A of the rotor 1, includes means for comparing the first voltage Ucos and the second voltage Usin to a predetermined minimum voltage value InfV ​​and a predetermined maximum voltage value SupV, includes means for calculating a sum USumSquare of the squares of the first voltage Ucos and the second voltage Usin, includes means for comparing the sum USumSquare to a predetermined lower acceptability threshold Saccmini and a predetermined upper acceptability threshold Saccmaxi, and includes means for generating an alarm signal to the user and / or a stop order for the electrical machine in the event of exceeding predetermined threshold values ​​for the first voltage Ucos, the second voltage Usin,and the sum USumSquare, and includes a fault memory for after-sales service.

[0104] In summary, information regarding the position of the electric machine's rotor is crucial, as it enables the calculation of the torque produced by the electric machine. Therefore, if the angular position sensor of the electric machine's rotor malfunctions, the measurement of the torque produced by the electric machine is inaccurate, and consequently, the electric machine's control system fails. This creates a risk of the electric machine becoming uncontrolled, and thus a risk of accidents for the vehicle user and those around them. The invention prevents this risk of uncontrolled operation.

[0105] The invention is applicable to all vehicles that have an electric traction machine, and is important because it relates to the safety of electric and plug-in hybrid vehicles.

[0106] This invention is applicable to all vehicles that have an electric traction machine.

[0107] In summary, the invention makes it possible to verify the plausibility of the information returned by the angular position sensor of the rotor of an electric machine, and therefore to control this electric machine in a safe manner.

Claims

1. Demands Method for monitoring the angle of the rotor (1) of an electric machine (2) comprising an electric or hybrid motor vehicle (100) comprising a powertrain control unit (3) and an electric motor control unit (4), said electric machine (2) being equipped with a sine / cosine rotation sensor (5) arranged to determine the angular position of said rotor (1), characterized in that, in a first step (10) the variation of the efficiency coefficient (p) of said electric machine (2) is measured on a test bench, for each speed step, for each torque step, for each voltage step, for each supply current step and for each stator temperature step,said efficiency coefficient (p) being the ratio (Pelec / Pmeca) between the mechanical power (Pmeca) transmitted at the output of said electric machine (2) to the traction chain of said motor vehicle (100) and the electrical power (Pelec) at the input of said electric machine (2), said measurement being translated into a map of the values ​​of said efficiency coefficient (p) which is stored in a memory that includes said control unit of the electric motor (4), in a second step (20) a first voltage (Ucos) proportional to the cosine of the angle (A) of the rotor and a second voltage (Usin) proportional to the sine of the angle (A) of said rotor (1) are collected by said sine / cosine rotation sensor (5), are compared to a minimum voltage value (InfV) and to a maximum voltage value (SupV),in a third step (30) a first test determines whether said first voltage (Ucos) and said second voltage (Usin) are each within the range whose limits are said minimum voltage value (InfV) and said maximum voltage value (SupV), and an alarm signal to the user and / or a stop order for said electric machine (2) is issued by said powertrain control unit (3) if said first voltage (Ucos) and / or said second voltage (Usin) is outside said range, and, if said first voltage (Ucos) and said second voltage (Usin) are each within said range in a fourth step (40) said electric motor control unit (4) calculates the sum (USumSquare) of the squares of said first voltage (Ucos), and second voltage (Usin), in a fifth step (50) a second test compares said sum (USumSquare) to a first lower acceptability threshold (Saccmini) and to a second upper acceptability threshold (Saccmaxi) predetermined, and an alarm signal to the user and / or a stop order of said electrical machine (2) is issued by said powertrain computer control unit (3) if said sum (USumSquare) is less than said first lower acceptability threshold (Saccmini) or greater than said second upper acceptability threshold (Saccmaxi), or said powertrain computer control unit (3) allows the continued operation of said electrical machine (2) if said sum (USumSquare) is between said first lower acceptability threshold (Saccmini) and said second upper acceptability threshold (Saccmaxi).

2. Method according to claim 1, characterized in that the values ​​of said first lower acceptability threshold (Saccmini) and of said second upper acceptability threshold (Saccmaxi) are calibrated during the selection of said sine / cosine rotation sensor (5) and of said first step (10), during which a function for monitoring the proper functioning of said sine / cosine rotation sensor (5) is developed.

3. A method according to claim 2, characterized in that if, in said fifth step (50), said electric motor control unit (4) finds that said sum (USumSquare) is less than said first lower acceptability threshold (Saccmini) or greater than said second upper acceptability threshold (Saccmaxi), in a sixth step (60) a transient time is measured during which said sum (USumSquare) exceeds said second upper acceptability threshold (Saccmaxi) or during which said sum (USumSquare) falls below said first lower acceptability threshold (Saccmini), and, if said transient time is greater than respectively a first predetermined time (D1), or a second predetermined time (D2), an alarm signal to the user and / or a stop order for said electric machine (2) is issued by said powertrain control unit (3).

4. A method according to claims 2 and 3, characterized in that said first duration (D1) is predetermined and said second duration (D2)

5.

6.

7. predetermined are calibrated during said first step (10), and during the development phase of said function of monitoring the proper functioning of said sensor of said sine / cosine rotation (5), and in that said first predetermined duration (D1) and said second predetermined duration (D2) are chosen between 80 ms and 120 ms. A method according to claim 3 or claim 4 depending on claim 3, characterized in that if said transient duration is greater than respectively said first predetermined duration (D1) or said second predetermined duration (D2), in a seventh step (70) said electric motor control unit (4) engages a reconfiguration strategy during which said electric motor control unit (4) stores a fault code in its read-only memory and communicates it to said powertrain control unit (3), to indicate to the after-sales that said electric motor control unit (4) has encountered a problem on said sine / cosine rotation sensor (5) and / or on said electric machine (2),and during which said electric motor control unit (4) requests said powertrain control unit (3) to illuminate a STOP indicator on the instrument panel of said vehicle (100) and / or to issue a message to said instrument panel to indicate to the user of said vehicle (100) the occurrence of a problem in the drivetrain. Method according to claim 5, characterized in that, during said seventh step (70), said electric motor control unit (4) commands the cessation of operation of said electric machine (2), including the memorization of a fault code, the lighting of a STOP light and the stopping of the electric machine. A method according to claim 3 or any one of the claims dependent on claim 3, characterized in that, if said transient duration is greater than said first predetermined duration (D1) or said second predetermined duration (D2), respectively, in an eighth step (80) said vehicle (100) is subjected to a recovery strategy implemented by the after-sales service, during which the read-only memory of said electric motor control unit (4) is erased and reconditioned, and during which said

8.

9.

10. sine / cosine rotation sensor (5) and said electrical machine (2) are checked and / or exchanged. A method of any one of claims 1 to 7, characterized in that, if after a shutdown of said electric machine (2) commanded by said powertrain control unit (3), and after the ignition is switched back on the fault, said electric motor control unit (4) ceases requesting the illumination of a STOP indicator and the display of a message on the instrument panel of said vehicle (100), and then said electric motor control unit (4) reauthorizes the operation of said electric machine (2). A method of any one of claims 1 to 8, characterized in that said sine / cosine rotation sensor (5) is a resolver. Motor vehicle (100) comprising at least one electric machine (2), a powertrain (9), a powertrain computer control unit (3), an electric motor control unit (4) for each said electric machine (2), each said electric machine (2) being equipped with a sine / cosine rotation sensor (5) or a resolver arranged to determine the angular position of said rotor (1), characterized in that said powertrain computer control unit (3) and / or at least one said electric motor control unit (4) comprises computing hardware and software means for implementing the method of any one of claims 1 to 9, comprises means for transmission with an external database comprising predetermined threshold values ​​of various parameters,or / and transmission means with a test bench performing a mapping of the values ​​of an efficiency coefficient (p) which is the ratio (Pelec / Pmeca) between the mechanical power (Pmeca) transmitted at the output of said electric machine (2) to the traction chain of said motor vehicle (100) and the electrical power (Pelec) at the input of said electric machine (2), includes a memory for storing said mapping, includes means for measuring and collecting by said sine / cosine rotation sensor (5) or said resolver a first voltage (Ucos) proportional to the cosine of the angle (A) of the rotor and a second voltage (Usin) proportional to the sine of the angle (A) of said rotor (1), includes means for comparing said first voltage (Ucos) and said second voltage, (Usin) at a predetermined minimum voltage value (InfV) and a predetermined maximum voltage value (SupV), includes means for calculating a sum (USumSquare) of the squares of said first voltage (Ucos) and second voltage (Usin), includes means for comparing said sum (USumSquare) to a predetermined first lower acceptability threshold (Saccmini) and second upper acceptability threshold (Saccmaxi), and includes means for generating an alarm signal to the user and / or a stop order for said electrical machine in the event of exceeding predetermined value thresholds for said first voltage (Ucos), said second voltage (Usin), and said sum (USumSquare), and includes a fault memory to inform after-sales service.

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