Piezoelectric pulse-width modulation measuring device for automotive vehicles

Abstract

The invention relates to a device (1) for measuring a parameter for a motor vehicle, comprising a main module (10) and a remote module (20) comprising a sensing element (230) configured to measure the parameter and a measurement stage configured to generate a pulse-width modulated signal whose duty cycle is representative of at least one value of the measured parameter. Figure 1

Description

Title of the invention: Pulse-width modulation piezoelectric measuring device for motor vehicles. Technical field

[0001] The present invention relates to the automotive field and more particularly concerns a piezoelectric PWM measurement device for motor vehicles and its implementation method. Previous technique

[0002] As is known, an electric motor comprises a rotor and a stator. The operation of such a motor causes the rotor and stator to heat up. However, the rotor's temperature rise can lead to performance losses and demagnetization of the magnets inside it beyond a certain temperature, which can result in damage or even motor failure. It is therefore necessary to measure the temperature inside the rotor in order to reduce its speed when the temperature approaches the critical operating limit and thus prevent damage to the motor or its failure.

[0003] Because of its rotation during operation, the rotor temperature is difficult to measure directly by wired temperature probes, so it is estimated by algorithms and models integrated into the motor management system.

[0004] However, these integrated algorithms and models result in measurement errors of up to plus or minus 20°C, which is not satisfactory for controlling the motor in order to avoid damaging it or causing its failure.

[0005] A simple, reliable and effective solution that would at least partially remedy these drawbacks would therefore be advantageous. Description of the invention

[0006] To this end, the invention first relates to a device for measuring a parameter for a motor vehicle, said device comprising a main module and a remote module, said main module comprising a control stage and a main piezoelectric transceiver configured to emit a power ultrasonic signal, said control stage being configured to electrically power said main piezoelectric transceiver and to control the emission of a power ultrasonic signal by said main piezoelectric transceiver, said remote module comprising a remote piezoelectric transceiver configured to receive the power ultrasonic signal emitted by the main piezoelectric transceiver, a sensitive element configured to measure said parameter and generate a measurement signal comprising at least one value of said parameter, and a measurement stage, connected on one side to the remote piezoelectric transceiver and on the other side to said sensing element and configured to collect and store the energy of the ultrasonic feed signal received by the remote piezoelectric transceiver, to electrically power the sensing element from said stored energy, to receive the measurement signal generated by the sensing element, to extract from said received measurement signal at least one value of the measured parameter, to generate a pulse-width modulated signal whose duty cycle is representative of at least one extracted value of the measured parameter, the remote piezoelectric transceiver being configured to convert the received pulse-width modulated signal into an ultrasonic measurement signal and to transmit said ultrasonic measurement signal to the main piezoelectric transceiver,The control stage is configured to determine the duty cycle of the ultrasonic measurement signal received by the main piezoelectric transceiver, whose duty cycle is identical to the duty cycle of the pulse-width modulation signal, in order to determine at least one value of the measured parameter.

[0007] The device according to the invention allows for remote measurements to be taken via the remote module by powering the sensing element with energy from signals sent by the main module over a wireless link. Thus, measurements can be taken very close to the magnets, thereby increasing the performance of the electrical machine control. The invention also eliminates the need for metallic barriers such as, for example, the casing and protective flanges, which block electromagnetic waves of the Wifi or Bluetooth type.

[0008] In one embodiment, the main piezoelectric transceiver and the remote piezoelectric transceiver are configured to resonate at least one predetermined frequency. The control stage is configured to generate a signal at said predetermined frequency and to supply the generated signal to the main piezoelectric transceiver, and the measurement stage is configured to generate a signal at said predetermined frequency and to supply the generated signal to the remote piezoelectric transceiver. Resonance optimizes the ultrasonic signal transmission rate and the current consumption between the transmitter and the receiver.

[0009] Alternatively or in addition, the remote module, comprising an external communication stage, allows the measurement stage to be configured to control the transmission of signals containing the measured values ​​via said external communication stage. The measured values ​​can thus be sent to an entity external to the measuring device for processing.

[0010] The external communication stage can, for example, transmit using a Bluetooth or RFID type communication protocol.

[0011] Advantageously, the control stage includes a memory area in which is stored a predetermined table, for example empirically, containing the correspondence between the duty cycle and a range of parameter values.

[0012] The invention also relates to an electric machine for a motor vehicle, said electric machine comprising a stator, a rotor and a measuring device as presented above, said electric machine being configured to be mounted in said vehicle in order to drive the wheels of said vehicle in rotation, electric machine in which the main module is mounted on the stator and the remote module is mounted on the rotor.

[0013] Advantageously, the remote module is mounted inside the rotor.

[0014] In one embodiment, the rotor comprising a shaft having a first shaft portion and a second shaft portion mounted on the stator by a bearing system, the first shaft portion having an end face extending orthogonally to the longitudinal axis of rotation of the rotor, the remote piezoelectric transmitter-receiver is mounted on said end face and the main piezoelectric transmitter-receiver is mounted on a portion of the stator facing said remote piezoelectric transmitter-receiver.

[0015] The invention also relates to a battery for a motor vehicle, comprising a measuring device as previously presented, the remote module being mounted so that the sensitive element is placed inside said battery.

[0016] The invention also relates to a group of batteries for a motor vehicle, comprising a measuring device as previously described, comprising at least one remote module mounted so that the sensing element is placed inside at least one of the batteries in the battery group.

[0017] The invention also relates to a fuel cell for a motor vehicle comprising a measuring device as previously presented, the remote module being mounted so that the sensitive element is placed inside said fuel cell.

[0018] The invention also relates to a motor vehicle comprising a measuring device as previously described.

[0019] In one embodiment, the vehicle is an electric or hybrid electric vehicle and includes an electric machine as described above.

[0020] In one embodiment, the vehicle includes a battery or a group of batteries or a fuel cell as described above.

[0021] The invention also relates to a method for measuring a parameter in a motor vehicle using a measuring device as described above, said method comprising the steps of:

[0022] - control, by the control stage, of the emission of an ultrasonic signal powered by the main piezoelectric transceiver,

[0023] - emission, by the main piezoelectric transceiver, of said ultrasonic signal food,

[0024] - reception, by the remote piezoelectric transceiver, of the ultrasonic signal power supply emitted,

[0025] - collection and storage, by the measurement stage, of the energy of the ultrasonic signal food,

[0026] - power supply, via the measuring stage, from the stored energy, of the sensitive element,

[0027] - measurement, by the sensitive element, of the parameter,

[0028] - generation, by the sensitive element, of a measurement signal comprising at least one value of the measured parameter,

[0029] - transmission, by the sensitive element, of said measurement signal generated at the stage of measure,

[0030] - reception, by the measurement stage, of the measurement signal,

[0031] - extraction, by the measurement stage, of at least one value of the measured parameter contained in the received measurement signal,

[0032] - generation, by the measurement stage, of a pulse-width modulated signal whose duty cycle is representative of at least one value of the extracted measured parameter,

[0033] - conversion, by the remote piezoelectric transceiver, of the signal to pulse width modulation received into an ultrasonic measurement signal,

[0034] - emission, by the remote piezoelectric transceiver, of said ultrasonic signal measurement intended for the main piezoelectric transceiver,

[0035] - determination, by the control stage, of the duty cycle of the ultrasonic signal measurement received

[0036] - determination, by the control stage, of at least one value of the parameter measured from the determined duty cycle. Brief description of the drawings

[0037] Other features and advantages of the invention will become apparent from the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings, in which:

[0038] [Fig-1] Fig. 1 schematically and functionally illustrates a first embodiment of the measuring device according to the invention.

[0039] [Fig.2] Fig.2 schematically and functionally illustrates a second embodiment of the measuring device according to the invention.

[0040] [Fig.3] Fig.3 schematically illustrates an example of an electrical machine according to the invention.

[0041] [Fig.4] Fig.4 schematically illustrates an example of a battery according to the invention.

[0042] [Fig. 5] [Fig. 5] schematically illustrates an example of a battery group according to the invention.

[0043] [Fig.6] Fig.6 schematically illustrates an example of a fuel cell according to the invention.

[0044] [Fig.7] Fig.7 schematically illustrates one embodiment of the process according to the invention. Description of the implementation methods

[0045] Figure 1 is an example of a measuring device 1 according to the invention. The device 1 is intended to be mounted in a motor vehicle.

[0046] Device 1 comprises a main module 10 and a remote module 20.

[0047] Main Module 10

[0048] The main module 10 includes a control stage 110 and a main piezoelectric transceiver 120.

[0049] The control stage 110 is configured to electrically supply said main piezoelectric transceiver 120 and to control the emission of ultrasonic signals by said main piezoelectric transceiver 120, preferably at a resonant frequency of said main piezoelectric transceiver 120.

[0050] The main piezoelectric transceiver 120 is configured to emit and receive ultrasonic signals, referred to as "power" signals SUA, to electrically power the remote module 20.

[0051] Preferably, the main piezoelectric transceiver 120 is configured to resonate at least one predetermined frequency, preferably at two predetermined frequencies, for example 200 kHz and 2 MHz.

[0052] Remote Module 20

[0053] The remote module 20 includes a remote piezoelectric transceiver 210, a measuring stage 220 and a sensitive element 230.

[0054] The remote piezoelectric transceiver 210 is configured to receive SUA power supply ultrasonic signals emitted by the main piezoelectric transceiver 120 and transmit them to the measurement stage 220.

[0055] Preferably, the remote piezoelectric transceiver 210 is configured to resonate at least one predetermined frequency, preferably at two predetermined frequencies, for example 200 kHz and 2 MHz.

[0056] The measuring stage 220 is connected on one side to the remote piezoelectric transmitter-receiver 210 and on the other side to the sensitive element 230.

[0057] The measuring stage 220 is configured to collect and store the energy of the SUA power supply ultrasonic signal transmitted by the remote piezoelectric transceiver 210 and to electrically power the sensitive element 230 from said stored energy.

[0058] The sensitive element 230 is configured to measure a parameter, for example air temperature, air pressure, humidity level, intensity of an electric current, mechanical force (stress), torque, etc.

[0059] It should be noted that the remote module 20 can include more than one sensitive element 230 to measure several different parameters and / or several identical parameters at different locations.

[0060] The sensitive element 230 is configured to generate a measurement signal S comprising one or more values ​​of said parameter.

[0061] The measuring stage 220 is configured to receive the measurement signal S generated by the sensitive element 230, to extract from said measurement signal S at least one value of the measured parameter and to generate a pulse width modulation (PWM) signal whose duty cycle is representative of at least one value of the measured parameter extracted.

[0062] The remote piezoelectric transceiver 210 is configured to convert the received pulse width modulation (PWM) signal into an ultrasonic measurement signal (SUM) and to transmit said ultrasonic measurement signal (SUM) to the main piezoelectric transceiver 120.

[0063] The control stage 110 is configured to determine the duty cycle of the ultrasonic measurement signal SUM received by the main piezoelectric transceiver 120, this duty cycle being identical to the duty cycle of the pulse width modulation PWM signal, and to determine at least one value of the measured parameter from said determined duty cycle.

[0064] The parameter value(s) can be determined from the duty cycle using a lookup table stored in a memory area of ​​the controlled stage 110. Such a table may have been determined beforehand empirically.

[0065] In another embodiment, illustrated in [Fig. 2], the remote module 20 comprising an external communication stage 240, the measurement stage 220 is configured to control the transmission of signals containing the measured parameter values ​​(extracted from the measurement signal S) via said external communication stage 240, in particular to an entity external to the device 1. This transmission can, for example, be carried out on a communication interface of the type Bluetooth, Wi-Fi, 5G or RFID, which are known per se. In this case, the external communication stage 240 preferably includes a microcontroller to implement this transmission function.

[0066] Examples of use of the measuring device according to the invention

[0067] Example 1: 300 electric machine

[0068] Figure 3 is an example of an electric machine 300 for a motor vehicle. The electric machine 300 is configured to be mounted in the vehicle in order to drive the wheels of said vehicle in rotation.

[0069] The electric machine 300 comprises a stator 310, a rotor 320 and a device 1 as previously presented.

[0070] The main module 10 is mounted on the stator 310 and the remote module 20 is mounted on the rotor 320.

[0071] The rotor 320 is configured to rotate around a longitudinal axis X.

[0072] In this example, the rotor 320 includes a material shaft 321 extending along the longitudinal axis X of rotation and comprising a first portion of axis 321A and a second portion of axis 321B connected to the stator 310 by means of a bearing system 315.

[0073] The first portion of the shaft 321A includes an end face 321A1 extending orthogonally to the longitudinal axis X of rotation of the rotor 320. The remote piezoelectric transceiver 210, the measuring stage 220 and the sensing element are mounted inside the rotor 320 and the main piezoelectric transceiver 120 is mounted on a portion of the stator 310 facing said end face 321A1.

[0074] Example 2: 400 battery

[0075] The [Fig.4] is an example of a 400 battery for a motor vehicle.

[0076] The main module 10 is placed at a distance from the battery 400 while the module remote 20 is mounted at the level of the battery 400 so that the sensitive element 230 measures a parameter inside said battery 400, for example temperature or pressure, humidity level, intensity of an electric current, mechanical force (stress), torque, or other.

[0077] It should be noted that the remote piezoelectric transceiver 210 and the measuring stage 220 can be mounted on an external face of the battery 400 or inside the battery 400 with the sensitive element 230, as in Example 1 of electric machine 300.

[0078] Example 3: 500 battery group

[0079] The [Fig.5] is an example of a 500 battery group for a motor vehicle.

[0080] The main module 10 is placed at a distance from the battery bank 500, while one or more remote modules 20 are mounted respectively at one or more of the batteries 400 of the battery bank 500 so that the sensitive element 230 of each remote module 20 measures a parameter inside each battery 400, for example temperature or pressure or other.

[0081] Example 4: 600 fuel cell

[0082] The [Fig.6] is an example of a 600 fuel cell for a motor vehicle.

[0083] The main module 10 is placed at a distance from the fuel cell 600 while The remote module 20 is mounted at the level of the fuel cell 600 so that the sensitive element 230 measures a parameter inside said fuel cell 600, for example at the level of the air supply circuit of the membranes of the fuel cell 600. Here again, the parameter(s) measured can for example be temperature, pressure, humidity level, intensity of an electric current, a mechanical force (stress) or a torque.

[0084] Example of implementation

[0085] An example of the implementation of device 1 will now be described with reference to [Fig. 7]. In this non-limiting example, the parameter to be measured may, for example, be the temperature, in particular inside a rotor 320 of an electric machine 300.

[0086] First, when it is necessary to measure the parameter, the control stage 110 of the main module 10, commands in a step El1, the emission of an ultrasonic power supply signal SUA by the main piezoelectric transceiver 120, preferably at one of the resonant frequencies to improve the transmission quality of said ultrasonic power supply signal SUA.

[0087] In a step E2, the main piezoelectric transceiver 120 emits the ultrasonic power supply signal SUA which is received by the remote piezoelectric transceiver 210 in a step E3 and transmitted to the measurement stage 220.

[0088] In a step E4, the measuring stage 220 collects and stores the energy of the SUA power supply ultrasonic signal and then electrically powers the sensitive element 230 from the energy stored in a step E5.

[0089] Once electrically powered, the sensitive element 230 measures in a step E6 the parameter of interest, which can for example be the air temperature, the air pressure, the humidity level, the intensity of an electric current, a mechanical force (stress) or a torque.

[0090] During the measurement of the parameter, the sensitive element 230 generates in a step E7 a measurement signal S comprising one or more values ​​of the measured parameter and then transmits in a step E8 the measurement signal S generated to the measurement stage 220.

[0091] The measuring stage 220 receives the measurement signal S transmitted in a step E9 and then extracts the value(s) of the measured parameter contained in the measurement signal S received in a step E10.

[0092] The measuring stage 220 then generates in a step El 1 a pulse-width modulation (PWM) signal whose duty cycle is representative of at least a value of the measured parameter is extracted. In particular, when several different values ​​are measured, the duty cycle varies according to these values. For example, a duty cycle of 25% may correspond to a temperature of 30°C, a duty cycle of 50% may correspond to a temperature of 50°C, and a duty cycle of 75% may correspond to a temperature of 70°C.

[0093] The remote piezoelectric transceiver 210 then converts, in a step El2, the received pulse width modulation (PWM) signal into an ultrasonic measurement signal SUM which is emitted by the remote piezoelectric transceiver 210 to the main piezoelectric transceiver 120 in a step E13.

[0094] The ultrasonic measurement signal SUM is received and transmitted by the main piezoelectric transceiver 120 to the control stage 110 which determines the duty cycle of the received ultrasonic measurement signal SUM in a step E14.

[0095] Finally, in a step E15, the control stage 110 determines at least one value of the measured parameter from the determined duty cycle, for example from the predetermined lookup table stored in its memory area.

[0096] The invention therefore makes it possible to measure a parameter using a remote module 20 powered remotely by electrical energy, thus avoiding the use of a battery to be changed, which is particularly advantageous in the case of an electric machine rotor.

Claims

1. Demands Device (1) for measuring a parameter for a motor vehicle, said device (1) comprising a main module (10) and a remote module (20), said main module (10) comprising a control stage (110) and a main piezoelectric transceiver (120) configured to emit a power ultrasonic signal (PUS), said control stage (110) being configured to electrically supply said main piezoelectric transceiver (120) and to control the emission of a power ultrasonic signal (PUS) by said main piezoelectric transceiver (120), said remote module (20) comprising a remote piezoelectric transceiver (210) configured to receive the power ultrasonic signal (PUS) emitted by the main piezoelectric transceiver (120), a sensing element (230) configured to measure said parameter and generate a measurement signal (S) comprising at least one value of said parameter, and a measurement stage (220),connected on one side to the remote piezoelectric transceiver (210) and on the other side to said sensing element (230), and configured to collect and store the energy of the ultrasonic power signal received by the remote piezoelectric transceiver (210), to electrically power the sensing element (230) from said stored energy, to receive the measurement signal (S) generated by the sensing element (230), to extract from said received measurement signal (S) at least one value of the measured parameter, to generate a pulse-width modulation (PWM) signal whose duty cycle is representative of at least one extracted value of the measured parameter, the remote piezoelectric transceiver (210) being configured to convert the received pulse-width modulation (PWM) signal into an ultrasonic measurement signal (SUM) and to transmit said ultrasonic measurement signal (SUM) to the main piezoelectric transceiver (120),the control stage (110) being configured to determine the duty cycle of the ultrasonic measurement signal (SUM) received by the main piezoelectric transceiver (120), whose duty cycle is identical to the duty cycle of the pulse-width modulation (PWM) signal in order to determine at least one value of the measured parameter.

2. Device (1) according to claim 1, wherein, the main piezoelectric transceiver (120) and the remote piezoelectric transceiver (210) being configured to resonate at least one same predetermined frequency, the control stage (110) is configured to generate a signal at said at least one predetermined frequency and to provide the generated signal to the main piezoelectric transceiver (120) and the measurement stage (220) is configured to generate a signal at said at least one predetermined frequency and to provide the generated signal to the remote piezoelectric transceiver (210).

3. Device (1) according to claim 1, wherein, the remote module (20) comprising an external communication stage (240), the measurement stage (220) is configured to control the transmission of a signal containing the measured values ​​via said external communication stage (240).

4. Device (1) according to any one of the preceding claims, wherein the control stage (110) includes a memory area in which is stored a predetermined table, for example empirically, comprising the correspondence between the duty cycle and a range of parameter values.

5. Electric machine (300) for motor vehicle, said electric machine (300) comprising a stator (310), a rotor (320) and a device (1) according to any one of the preceding claims, said electric machine (300) being configured to be mounted in said vehicle in order to drive the wheels of said vehicle in rotation, electric machine (300) in which the main module (10) is mounted on the stator (310) and the remote module (20) is mounted on the rotor (320).

6. Electric machine (300) according to the preceding claim, wherein the remote module (20) is mounted inside the rotor (320).

7. An electric machine (300) according to any one of claims 5 or 6, wherein the rotor (320) comprises a shaft (321) having a first shaft portion (321A) and a second shaft portion (321B) mounted on the stator (310) by a bearing system (315), the first shaft portion (321A) having an end face (321A1) extending orthogonally to the longitudinal axis (X) of rotation of the rotor (320), and the remote piezoelectric transmitter-receiver (210) is mounted on said end face (321A1) and the main piezoelectric transceiver (120) is mounted on a portion of the stator (310) facing said remote piezoelectric transceiver (210).

8. Battery group (500) for motor vehicle, comprising a measuring device (1) according to any one of claims 1 to 4, the remote module (20) being mounted so that the sensing element (230) is placed inside at least one battery (400) of the battery group (500).

9. Motor vehicle comprising a measuring device (1) according to any one of claims 1 to 4.

10. A method for measuring a parameter in a motor vehicle from a measuring device (1) according to any one of claims 1 to 4, said method comprising the steps of: - control (E1), by the control stage (110), of the emission of a power ultrasonic signal (SUA) by the main piezoelectric transceiver (120), - emission (E2), by the main piezoelectric transceiver (120), of said power ultrasonic signal (SUA), - reception (E3), by the remote piezoelectric transceiver (210), of the emitted power ultrasonic signal (SUA), - collection and storage (E4), by the measuring stage (220), of the energy of the power ultrasonic signal (SUA), - power supply (E5), by the measuring stage (220), from the stored energy, to the sensing element (230), - measurement (E6), by the sensitive element (230), of the parameter, - generation (E7), by the sensitive element (230),of a measurement signal (S) containing at least one value of the measured parameter, - transmission (E8), by the sensitive element (230), of said measurement signal (S) generated at the measurement stage (220), - reception (E9), by the measurement stage (220), of the measurement signal (S), - extraction (E10), by the measurement stage (220), of at least one value of the measured parameter contained in the received measurement signal (S), - generation (E11), by the measurement stage (220), of a pulse-width modulation (PWM) signal whose duty cycle is representative of at least one extracted value of the measured parameter, - conversion (E12), by the remote piezoelectric transceiver (210), of the received pulse width modulation (PWM) signal into an ultrasonic measurement signal (SUM), - emission (E13), by the remote piezoelectric transceiver (210), of said ultrasonic measurement signal (SUM) to the main piezoelectric transceiver (120), - determination (E14), by the control stage (110), of the duty cycle of the received ultrasonic measurement signal (SUM), - determination (E15), by the control stage (110), of at least one value of the measured parameter from the determined duty cycle.

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