FR3137351A1 - MONITORING THE VOLTAGE DELIVERED BY A SPEED DETECTOR OF A ROTOR OF AN ELECTRIC MOTOR MACHINE OF A VEHICLE - Google Patents

Abstract

A monitoring method is implemented in a vehicle comprising an electric driving machine comprising a stator capable of driving a rotor in rotation at a speed represented by an output voltage delivered by a speed detector. This method comprises a step (10-30) in which, when this delivered output voltage is lower than a first chosen threshold, operation of the electric motor machine is temporarily prohibited. Figure 3

Description

MONITORING THE VOLTAGE DELIVERED BY A SPEED DETECTOR OF A ROTOR OF AN ELECTRIC MOTOR MACHINE OF A VEHICLE Technical field of the invention

The invention concerns vehicles comprising an electric driving machine with a stator and rotor, and more specifically the monitoring of the voltage delivered by a speed detector associated with such a rotor.

State of the art

Certain vehicles, possibly of the automobile type, include a powertrain (or GMP) comprising an electric driving machine supplied with electrical energy by an on-board electrical energy source, such as for example a main (or traction) battery or a fuel cell , in order to at least provide torque.

The electric driving machine is generally an electric motor comprising a rotor and a stator. When such an electric motor machine is in operation, for example to provide (positive) torque for the wheels of a train of its vehicle, its stator consumes electrical energy supplied by the electrical energy source to create at minus a magnetic field intended to rotate the rotor.

For example, when the electric motor machine is of the so-called “permanent magnet synchronous” type, it comprises a permanent magnet rotor and a stator comprising N coils (with N ≥ 3) placed around the rotor and powered, so controlled by a machine computer associated with the electric driving machine, in current pulses having directions of circulation chosen so as to make each of them attractive or repulsive or neutral (no current) at a precise instant. These current pulses are determined according to a setpoint defining the torque to be supplied by the electric motor (and therefore its rotor) on its output and which is determined by a vehicle GMP supervision calculator as a function of the percentage of depressing the accelerator pedal.

So that the torque which is actually supplied by the electric motor machine is as close as possible to the torque setpoint, the torque actually supplied can be the subject of an estimation by means of a technique based on the use of at least one speed detector associated with the rotor and taking into account, in particular, the voltage on the input terminals of the electric motor machine and the speed (or speed) of rotation of the rotor deduced from an output voltage delivered by this speed detector. When the difference between the torque setpoint and the estimate of the torque actually supplied becomes greater than a chosen torque difference, an alert is generated and the GMP supervision computer orders operation of the electric drive machine in a degraded mode.

It therefore appears particularly important for controlling the operation of such an electric motor machine to have a reliable rotor rotation speed at all times. Therefore, the speed detector is currently associated with a current detector which is responsible for monitoring whether it is not short-circuited to ground through measurements of the current supplying this speed detector. Unfortunately, these current measurements are unreliable and the current detector turns out to be bulky and expensive.

The invention therefore aims in particular to improve the situation.

Presentation of the invention

For this purpose, it proposes in particular a monitoring method intended to be implemented in a vehicle comprising an electric motor machine comprising a stator capable of driving a rotor in rotation at a speed which is represented by an output voltage delivered by a detector of speed.

This monitoring method is characterized by the fact that it comprises a step in which, when the output voltage delivered is lower than a first chosen threshold, operation of the electric motor machine is temporarily prohibited.

Thus, we can now completely do without the current detector which was until now responsible for monitoring whether the speed detector was short-circuited to earth, because we now deduce from the analysis of the output voltage delivered by the speed detector whether or not there is a short circuit to earth.

The monitoring method according to the invention may include other characteristics which can be taken separately or in combination, and in particular:

- in its step, the operation of the electric motor machine can be temporarily prohibited when output voltages delivered successively are lower than the first threshold for a duration which is greater than a second chosen threshold;

- in the presence of the first option, in its step, the second threshold can be between 10 ms and 200 ms;

- in its stage, the first threshold can be between 0.25 V and 0.45 V;

- in its stage, in the event of a temporary ban on the operation of the electric motor, it is also possible to carry out in the vehicle at least one complementary action chosen from a generation of an alert for a user of the vehicle of this ban and a need to stop the vehicle and a recording of at least one fault code representative of a short circuit to ground problem of the speed detector;

- in its step, the operation of the electric motor machine can be re-authorized when the output voltage delivered is greater than a third threshold chosen after waking up the vehicle after falling asleep in the presence of a ban on operation of the machine electric motor.

- in the presence of the last option, in its step, the third threshold can be equal to the first threshold.

The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a monitoring method of the type of that presented above to monitor , in a vehicle, an output voltage delivered by a speed detector and representative of a rotational speed of a rotor forming part of an electric motor machine also comprising a stator capable of rotating this rotor.

The invention also proposes a monitoring device intended to equip a vehicle comprising an electric driving machine comprising a stator capable of driving a rotor in rotation at a speed represented by an output voltage delivered by a speed detector.

This monitoring device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting, when the output voltage delivered is lower than a first chosen threshold, of temporarily prohibiting operation of the electric driving machine.

The invention also proposes a vehicle, possibly of the automobile type, and comprising:

- an electric motor machine comprising a stator capable of driving a rotor in rotation at a speed represented by an output voltage delivered by a speed detector, and

- a monitoring device of the type presented above.

Brief description of the figures

Other characteristics and advantages of the invention will appear on examination of the detailed description below, and the appended drawings, in which:

schematically and functionally illustrates an exemplary embodiment of a vehicle comprising a GMP, with an electric motor with a rotor associated with a speed detector, and a monitoring device according to the invention,

schematically and functionally illustrates an exemplary embodiment of a machine computer comprising an exemplary embodiment of a monitoring device according to the invention, and

schematically illustrates an example of an algorithm implementing a monitoring method according to the invention.

Detailed description of the invention

The invention aims in particular to propose a monitoring method, and an associated DS monitoring device, intended to allow monitoring of the output voltage ts which is delivered by a speed detector DV and representative of the rotation speed d a rotor RM forming part of an electric motive machine MME fitted to a vehicle V, in order to detect a short circuit to earth of this speed detector DV.

In what follows, we consider, by way of non-limiting example, that the vehicle V is of the automobile type. This is for example a car, as illustrated in the . But the invention is not limited to this type of vehicle. It concerns in fact any type of vehicle comprising a powertrain (or GMP) comprising an electric driving machine with stator and rotor and supplied with electrical energy by an electrical energy source, such as for example a main (or traction) battery or a fuel cell. Thus, it concerns, for example, land vehicles (utility vehicles, motorhomes, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery, agricultural machinery, leisure machinery (snowmobile, kart), and road machinery. caterpillar(s), for example), boats and aircraft.

Furthermore, we consider in what follows, by way of non-limiting example, that the vehicle V comprises a powertrain (or GMP) of all-electric type (and therefore whose traction is ensured exclusively by at least one electric driving machine MRS). But the GMP could be of hybrid type (thermal and electric).

Furthermore, we consider in what follows, by way of non-limiting example, that the electric driving machine MME is supplied with electrical energy by a source of electrical energy in the form of a main (or traction) battery. ) which is rechargeable at least during charging phases. But the MME electric driving machine could be supplied with electrical energy by a fuel cell.

Finally, we consider in what follows, by way of non-limiting example, that the MME electric motor machine is of the so-called “permanent magnet synchronous” type. But other types of electric driving machine can be used, as long as they include a rotor and a stator.

We have schematically represented on the a vehicle V comprising a transmission chain with electric GMP (and therefore with an electric driving machine MME associated with a machine computer CM and a speed detector DV), an on-board network RB, a service battery BS, a source of electrical energy SE (here a main (or traction) battery), a CV converter, and a DS monitoring device according to the invention.

The RB on-board network is an electrical supply network to which electrical (or electronic) equipment (or components) are coupled which consume electrical energy.

The utility battery BS is responsible for supplying electrical energy to the on-board network RB, in addition, here, to that supplied by the CV converter powered by the electrical energy source SE (here a main (or traction) battery )), and sometimes instead, here, of this CV converter. For example, this BS utility battery can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least via the CV (current) converter. We consider in the following, by way of non-limiting example, that the BS utility battery is of the 12 V Lithium-ion type.

The transmission chain has a GMP which is, here, purely electric and therefore which includes, in particular, an electric driving machine MME, an AM motor shaft, and an AT transmission shaft. Here we mean “electric driving machine” an electric machine arranged so as to provide torque to move the vehicle V when it is supplied with electrical energy (here) by the main battery SE, as well as possibly to recover torque when regenerative braking phases.

The operation of the GMP is supervised by a CS supervision computer.

The electric driving machine MME (here a permanent magnet synchronous electric motor, as an example) is here coupled to the main battery SE, in order to be supplied with electrical energy, as well as possibly to power this main battery SE in electrical energy, particularly during regenerative braking. The operation of the MME electric driving machine is controlled by the associated CM machine computer.

This electric motor machine MME comprises a stator SM responsible for rotating its rotor RM with which the speed detector DV is associated.

In the example illustrated, the electric motor machine MME comprises a permanent magnet rotor RM and a stator SM comprising N coils Bn (with N ≥ 3) placed around the rotor RM and powered, in a manner controlled by the machine computer CM, in current pulses having directions of circulation chosen so as to make each of them attractive or repulsive or neutral (no current) at a precise moment. It will be understood that this rotational drive of the rotor RM makes it possible to produce torque to move the vehicle V.

It will be noted that in the example illustrated non-limitingly on the the SM stator includes three coils B1 to B3 (n = 1 to 3, N = 3). But the stator SM can include any number of coils Bn as long as this number is greater than or equal to three.

For example, each coil Bn of the stator SM can be associated with a detector Dn responsible for detecting the current which flows between its terminals. Also for example, each detector Dn can periodically deliver, for the machine computer CM, a voltage udn which is representative of the current circulating in the associated coil Bn. In this case, to operate each detector Dn is powered by a predefined electric current under a predefined voltage under the control of the machine computer CM. For example, each detector Dn can behave like a resistor whose resistance value varies according to the current circulating in the associated coil Bn, and therefore varies the predefined voltage.

The speed detector DV is arranged so as to deliver an output voltage ts which is representative of the speed (or speed) of rotation vrm of the rotor RM. For example, this speed detector DV can deliver an output voltage ts periodically. The period can, for example, be equal to 100 µs. In this case, the machine computer CM deducts every 100 µs the rotation speed vrm from the output voltage ts delivered by the speed detector DV.

Also for example, this speed detector DV can include a toothed wheel which is fixedly secured around the output axis of the rotor RM (which supplies the torque to the motor shaft AM) and a sensor which counts the number of teeth passing in front of it, and deduces from this number, periodically, an output voltage ts which is representative of the rotation speed vrm.

It will be noted that the torque cs which is supplied by the electric motor machine MME on its output can, for example, be estimated by a technique using at least part of the measurements (voltages udn and rotation speed vrm) delivered by the detectors Dn and the speed detector DV and the voltage tbe estimated on the input terminals of the electric motor machine MME.

As an illustrative example, this technique can make it possible to estimate the torque supplied cs as a function of at least the estimated voltage tbe, a current ism delivered at the output of the electric motor machine MME, the rotation speed vrm of the rotor RM (represented by the output voltage ts), and the current taken by the electric driving machine MME (here in the main battery SE).

Indeed, as those skilled in the art know, the estimate of the torque supplied cs is given by the equation cs = (tbe * ism * µ) / vrm. µ is an efficiency coefficient of the electric driving machine MME which is determined using the rotation speed vrm of the rotor RM, the current taken by the electric driving machine MME (here in the main battery SE) and the estimated voltage tbe ( as well as possibly the internal temperature of the SM stator).

The previous equation follows from the fact that the electric power pelec received by the electric driving machine MME on its input terminals is equal to the product (tbe * ism), and that the electric driving machine MME provides at output a mechanical power pmeca which is equal to the product (cs * vrm) but also to the product (pelec * µ), and that consequently we have the equation (cs * vrm) = (tbe * ism * µ).

Furthermore, the electric driving machine MME is coupled to the motor shaft AM, to provide it with torque by rotational drive. This motor shaft AM is here coupled to a reduction gear RD which is also coupled to the transmission shaft AT, itself coupled to a first train T1 (here of wheels), preferably via a differential DF.

This first train T1 is here located in the front part PVV of the vehicle V. But in a variant this first train T1 could be the one which is here referenced T2 and which is located in the rear part PRV of the vehicle V.

The CV converter is also responsible, here, during the driving phases of the vehicle V, of converting part of the electric current stored in the main battery SE to supply converted electric current to the on-board network RB and the service battery BS (for the reload).

Note, as illustrated non-limitatively in the , that the CV converter can be part of a CH charger also comprising a recharge calculator (not illustrated) responsible, at least, for controlling the recharges of the main battery SE.

The main (or traction) battery SE can, for example, comprise electrical energy storage cells, possibly electrochemical (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type). Also for example, the main battery SE can be of the low voltage type (typically 450 V for illustration purposes). But it could be medium voltage or high voltage.

It should also be noted that the main battery SE is associated with a battery box BB which notably includes a battery calculator CB. This SE main battery and its BB battery box constitute a battery pack.

It will also be noted that in the example illustrated non-limitingly on the the vehicle V also includes a distribution box BD to which the utility battery BS, the CV converter and the on-board network RB are coupled. This distribution box BD is responsible for distributing in the on-board network RB the electrical energy stored in the utility battery BS or produced by the converter CV, for powering the electrical components (or equipment) coupled to the on-board network RB depending on power requests received (in particular from the GMP CS supervision computer).

As mentioned above, the invention proposes in particular a monitoring method intended to allow monitoring of the output voltage ts which is delivered by the speed detector DV and representative of the rotation speed of the rotor RM, in order to detect a short -ground circuit of this DV speed detector.

This (monitoring) method can be implemented at least partially by the monitoring device DS (illustrated at least partially in Figures 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal (or DSP (“Digital Signal Processor”)), and at least one MD memory. This DS monitoring device can therefore be produced in the form of a combination of electrical or electronic circuits or components (or “hardware”) and software modules (or “software”). For example, it can be a microcontroller.

The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the monitoring process. The processor PR1 may include integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or non-wired connections. By integrated (or printed) circuit we mean any type of device capable of performing at least one electrical or electronic operation.

In the example illustrated non-limitingly in Figures 1 and 2, the monitoring device DS is part of the machine computer CM (associated with the electric motor machine MME). But this is not obligatory. Indeed, the monitoring device DS could include its own dedicated computer, which is then coupled to the machine computer CM, or could be part of another on-board computer (for example the supervision computer CS or the battery computer CB ).

As illustrated without limitation on the , the (monitoring) method, according to the invention, comprises a step 10-30 which is implemented when the GMP of the vehicle V is in operation, and in particular when the electric motive machine MME is in operation.

Step 10-30 of the method comprises a sub-step 20 in which, when the output voltage ts delivered is less than a first chosen threshold s1, (the monitoring device DS) temporarily prohibits the operation of the electric motor machine MRS.

We consider in fact that, if the speed detector DV operates correctly, then the output voltage ts that it delivers must be greater than the first threshold s1. Consequently, if this is not the case, it is because the speed detector DV is not working correctly and therefore it is necessary to act accordingly by temporarily prohibiting the operation of the electric motor machine MME to prevent it from running away, which could pose a risk to vehicle V and its passengers and/or to people and objects located near vehicle V.

Thanks to the invention, we can now completely do without the current detector which was until now responsible for monitoring whether the speed detector DV was short-circuited to earth, because we now deduce from the analysis of the output voltage ts delivered by the speed detector DV if the latter (DV) is, or not, in a short-circuit situation to earth. This is particularly advantageous because it not only reduces space requirements and costs, but also significantly increases the reliability of the detection of a short circuit to earth of the DV speed detector.

For example, in step 10-30, when the voltage of the on-board network RB and the speed detector DV delivers in normal operation a voltage close to 0.5 V when the rotation speed of the rotor RM is zero, the first threshold s1 can be between 0.25 V and 0.45 V. As an illustrative example, the first threshold s1 can be equal to 0.35 V. But other values of first threshold s1 can be used ( in particular when the voltage of the on-board network RB (which supplies the speed detector DV) is 24 V or 48 V).

In order to make a decision in sub-step 20, as illustrated without limitation in the , we can provide a sub-step 10 of step 10-30 in which we (the monitoring device DS) compare the output voltage ts delivered to the first threshold s1. In this case, as indicated above, if the output voltage ts delivered is greater than the first threshold s1 we return to carry out substep 10 with a new output voltage ts, while if the output voltage ts delivered is less than the first threshold s1, sub-step 20 is carried out to temporarily prohibit the operation of the electric motor machine MME.

It will be noted that in sub-step 20 of step 10-30 we (the monitoring device DS) can temporarily prohibit the operation of the electric motor machine MME when the output voltages ts delivered successively by the speed detector DV are all lower than the first threshold s1 for a duration which is greater than a second chosen threshold s2. This option makes it possible to avoid taking into account a single erroneous or occasionally abnormal ts output voltage (compared to the other ts output voltages delivered just before or just after) which would cause the immediate performance of a main action (i.e. the temporary ban on the operation of the MME electric driving machine).

Also for example, in step 10-30 the second threshold s2 can be between 10 ms and 200 ms. As an illustrative example, the second threshold s2 can be equal to approximately 20 ms. But other values of second threshold s2 can be used.

In order to determine the duration of a short circuit problem to earth of the speed detector DV, we (the monitoring device DS) can trigger in substep 10 a first time delay equal to the duration of the second threshold s2 from that the output voltage ts delivered becomes lower than the first threshold s1 for the first time, and, when this duration of the second threshold s2 expires (and we still have ts < s1), we decide in substep 20 d 'at least temporarily prohibit the operation of the MME electric driving machine.

It will also be noted that in sub-step 20 of step 10-30, when the temporary ban on operation of the electric motor machine MME has been decided, it is also possible to carry out (the monitoring device DS can trigger the implementation) in the vehicle V with (at) least one complementary action chosen from:

- the generation of an alert to the user (or driver) of vehicle V of this prohibition and of a need to stop vehicle V, and

- the recording of at least one fault code representative of a short circuit to earth problem of the DV speed detector.

The user of the vehicle V can be alerted, for example, by means of a lit indicator light (for example on the dashboard) and/or a message displayed on at least one screen of the vehicle V (for example example of the dashboard or a central handset) or on the screen of the user's smartphone (or "smartphone"), and/or broadcast by at least one speaker of the vehicle V or this smartphone . This alert is intended to warn the driver of the fact that the operation of the MME electric driving machine has been interrupted, so that he is not surprised by possible freewheeling (when the GMP is all electric) and therefore that he quickly parks his vehicle V in a secure manner, then alerts an after-sales service for assistance.

The recording of at least one fault code representative of a short circuit to earth problem of the DV speed detector (and therefore of a temporary ban on operation of the MME electric motor) is intended to facilitate research. of the origin of this prohibition by a technician from an after-sales service, and to allow this technician to solve the problem and to inform the user of vehicle V of the origin of this prohibition.

It will also be noted that step 10-30 can also include a sub-step 30 in which it is considered that there is no longer a problem of short circuit to ground of the speed detector DV when the output voltage ts delivered is greater than a third threshold s3 chosen after waking up the vehicle V subsequent to its falling asleep in the presence of a ban on operation of the electric motive machine MME. In this case, the operation of the electric motive machine MME is re-authorized, which amounts to re-authorizing the driver (user) of the vehicle V to normally use the latter (V). Preferably, we also stop generating an (the DS monitoring device stops triggering the generation of a) alert for the user (when this additional action is planned).

Of course, if the problem of a short circuit to earth of the DV speed detector is detected again, a new ban on the operation of the MME electric motive machine is imposed.

For example, the third threshold s3 can be equal to the first threshold s1. But this is not obligatory.

Note also, as illustrated non-limitatively in the , that the machine computer CM (or the dedicated computer of the monitoring device DS) can also include a mass memory MM1, in particular for the temporary storage of successive output voltages ts, and any intermediate data involved in all its calculations and treatments. Furthermore, this CM machine calculator (or the dedicated calculator of the DS monitoring device) can also include an IE input interface for receiving at least the output voltages ts, to use them in calculations or processing, possibly after having shaped and/or demodulated and/or amplified them, in a manner known per se, by means of a digital signal processor PR2. In addition, this CM machine computer (or the dedicated computer of the DS monitoring device) can also include an IS output interface, in particular to deliver alarm generation orders, alarm generation stop orders, orders prohibiting operation of the MME electric motor machine, orders authorizing operation of the MME electric motor machine, and messages containing a fault code.

It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the monitoring method described above to monitor the output voltage ts delivered by the speed detector DV and representative of the rotation speed of the rotor RM of the electric motor machine MME of the vehicle v.

Claims (10)

Monitoring method for a vehicle (V) comprising an electric motor machine (MME) comprising a stator (SM) capable of driving a rotor (RM) in rotation at a speed represented by an output voltage delivered by a speed detector (DV ), characterized in that it comprises a step (10-30) in which, when said delivered output voltage is lower than a first chosen threshold, operation of said electric motor machine (MME) is temporarily prohibited. Method according to claim 1, characterized in that in said step (10-30) the operation of said electric motor machine (MME) is temporarily prohibited when output voltages delivered successively are lower than said first threshold for a duration greater than a second chosen threshold. Method according to claim 2, characterized in that in said step (10-30) said second threshold is between 10 ms and 200 ms. Method according to one of claims 1 to 3, characterized in that in said step (10-30) said first threshold is between 0.25 V and 0.45 V. Method according to one of claims 1 to 4, characterized in that in said step (10-30), in the event of a temporary ban on the operation of said electric motor machine (MME), said vehicle (V) is also carried out at least one complementary action chosen from generating an alert from a user of the vehicle of said prohibition and a need to stop said vehicle (V) and a recording of at least one fault code representative of a problem short circuit to earth of said speed detector (DV). Method according to one of claims 1 to 5, characterized in that in said step (10-30) the operation of said electric motor machine (MME) is re-authorized when said output voltage delivered is greater than a third chosen threshold after waking up said vehicle (V) subsequent to falling asleep in the presence of a ban on operation of said electric motor machine (MME). Method according to claim 6, characterized in that in said step (10-30) said third threshold is equal to said first threshold. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the monitoring method according to one of claims 1 to 7 for monitoring, in a vehicle ( V), an output voltage delivered by a speed detector (DV) and representative of a rotation speed of a rotor (RM) forming part of an electric motor machine (MME) also comprising its own stator (SM). to rotate said rotor (RM). Monitoring device (DS) for a vehicle (V) comprising an electric motor machine (MME) comprising a stator (SM) capable of driving a rotor (RM) in rotation at a speed represented by an output voltage delivered by a detector of speed (DV), characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, when said delivered output voltage is less than a first chosen threshold, of prohibiting temporarily operation of said electric motor machine (MME). Vehicle (V) comprising an electric motor machine (MME) comprising a stator (SM) capable of driving a rotor (RM) in rotation at a speed represented by an output voltage delivered by a speed detector (DV), characterized in that that it further comprises a monitoring device (DS) according to claim 9.