Piezoelectric measuring device with pwm for motor vehicle

Abstract

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

Description

[Technical Field] This invention relates to the automotive field, and more particularly to a PWM-based piezoelectric measuring device for motor vehicles and a method for implementing the piezoelectric measuring device. [Background Technology] As is known, an electric motor consists of a rotor and a stator. The operation of such a motor causes both the rotor and stator to heat up. However, elevated rotor temperature can lead to performance loss, and when a certain temperature is exceeded, it can cause the internal magnets to demagnetize, potentially damaging or even causing the motor to fail. Therefore, it is necessary to measure the internal temperature of the rotor in order to reduce its speed when the rotor temperature approaches its critical operating limits, thereby avoiding damage to the motor or preventing its failure.

[0001] Because the rotor rotates during operation, its temperature is difficult to measure directly using wired temperature sensors. Therefore, the temperature is estimated using algorithms and models integrated into the motor's management system.

[0002] However, these integrated algorithms and models result in measurement errors that can reach plus or minus 20°C, which is unsatisfactory for controlling motors to prevent damage or failure.

[0003] Therefore, a simple, reliable, and efficient solution to at least partially overcome these shortcomings would be advantageous. [Summary of the Invention] Therefore, the subject of this invention is primarily an apparatus for measuring parameters of a motor vehicle, the apparatus comprising a main module and a remote module. The main module includes a control stage and a main piezoelectric transceiver configured to transmit an ultrasonic power supply signal. The control stage is configured to power the main piezoelectric transceiver and command it to transmit the ultrasonic power supply signal. The remote module includes: a remote piezoelectric transceiver configured to receive the ultrasonic power supply signal transmitted by the main piezoelectric transceiver; a sensing element configured to measure the parameters and generate a measurement signal including at least one value of the parameters; and a measurement stage connected on one side to the remote piezoelectric transceiver and on the other side to the sensing element, and configured to... The system is configured to collect and store the energy of the ultrasonic power supply signal received by the remote piezoelectric transceiver, use the stored energy to power the sensitive element, receive the measurement signal generated by the sensitive element, extract at least one value of the measured parameter from the received measurement signal, and generate a pulse width modulation signal whose duty cycle represents at least one value of the extracted measured parameter. The remote piezoelectric transceiver is configured to convert the received pulse width modulation signal into an ultrasonic measurement signal and transmit the 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, the duty cycle of the ultrasonic measurement signal being the same as the duty cycle of the pulse width modulation signal, in order to determine at least one value of the measured parameter.

[0004] The device according to the invention allows for remote measurement via a remote module, using energy from a signal transmitted wirelessly by the main module to power a sensitive measuring element. Therefore, measurements can be performed as close as possible to the magnet, improving the control performance of the electric machine. The invention also eliminates the need for metal barriers (e.g., housings and protective flanges) that block electromagnetic waves of the Wi-Fi or Bluetooth type.

[0005] In one embodiment, the primary piezoelectric transceiver and the remote piezoelectric transceiver are configured to resonate at at least one given predetermined frequency. The control stage is configured to generate a signal at the at least one predetermined frequency and transmit the generated signal to the primary piezoelectric transceiver. The measurement stage is configured to generate a signal at the at least one predetermined frequency and transmit the generated signal to the remote piezoelectric transceiver. Resonance allows for optimization of the ultrasonic signal transmission rate and the current consumption between the transmitter and receiver.

[0006] Alternatively or additionally, the remote module includes an external communication stage, the measurement stage being configured to command the transmission of signals containing these measured values ​​via the external communication stage. Thus, the measured values ​​can be sent to an entity outside the measuring device for processing.

[0007] External communication can be transmitted using communication protocols such as Bluetooth or RFID.

[0008] Advantageously, the control level includes a memory region that stores a table, for example, predetermined based on experience, and the table contains a correspondence between duty cycles and ranges of parameter values.

[0009] The present invention also relates to an electric motor for a motor vehicle, the electric motor comprising a stator, a rotor and a measuring device as described above, the electric motor being configured to be installed in the vehicle to drive the wheels of the vehicle to rotate, wherein the main module is mounted on the stator and the remote module is mounted on the rotor.

[0010] Advantageously, the remote module is installed inside the rotor.

[0011] In one embodiment, the rotor includes a shaft comprising a first shaft portion and a second shaft portion mounted on the stator via a bearing system. The first shaft portion includes an end face extending orthogonally to the longitudinal axis of rotation of the rotor. The remote piezoelectric transceiver is mounted on the end face, and the main piezoelectric transceiver is mounted on the portion of the stator facing the remote piezoelectric transceiver.

[0012] The present invention also relates to a battery for a motor vehicle, the battery including the measuring device as described above, wherein a remote module is mounted such that a sensitive element is placed inside the battery.

[0013] The present invention also relates to a battery pack for a motor vehicle, the battery pack including the measuring device as described above, the measuring device including at least one remote module, the at least one remote module being mounted such that a sensitive element is placed inside at least one cell of the battery pack.

[0014] The present invention also relates to a fuel cell for a motor vehicle, the fuel cell including the measuring device as described above, wherein a remote module is mounted such that a sensing element is placed inside the fuel cell.

[0015] The present invention also relates to a motor vehicle that includes the measuring device described above.

[0016] In one embodiment, the vehicle is an electric vehicle or a hybrid electric vehicle, and includes the electric motor described above.

[0017] In one embodiment, the vehicle includes a battery or battery pack or fuel cell as described above.

[0018] The present invention also relates to a method for measuring parameters in a motor vehicle using the measuring device described above, the method comprising the following steps: - The control level commands the main piezoelectric transceiver to transmit ultrasonic power signals. - The ultrasonic power supply signal is transmitted by the main piezoelectric transceiver. - The emitted ultrasonic power supply signal is received by a remote piezoelectric transceiver. - The energy of the ultrasonic power signal is collected and stored by the measuring stage. - The measurement stage uses stored energy to power the sensitive element. - Parameters measured by a sensitive element, - A measurement signal is generated by a sensing element, including at least one value of the parameter being measured. - The generated measurement signal is transmitted to the measurement stage by the sensitive element. - The measurement signal is received by the measurement stage. - The measurement stage extracts at least one value of the measured parameter contained in the received measurement signal. - A pulse width modulated signal whose duty cycle represents at least one value of the extracted measured parameter is generated by the measurement stage. - The received pulse width modulation signal is converted into an ultrasonic measurement signal by a remote piezoelectric transceiver. - The ultrasonic measurement signal is transmitted from the remote piezoelectric transceiver to the main piezoelectric transceiver. - The duty cycle of the received ultrasonic measurement signal is determined by the control level. - The control level determines at least one value of the measured parameter based on the determined duty cycle. [Image Description] Other features and advantages of the invention will become more apparent upon reading the following description. This description is purely illustrative and should be read with reference to the accompanying drawings, in which: [ Figure 1 ] Figure 1 A first embodiment of the measuring device according to the present invention is illustrated schematically in a functional manner.

[0019] [ Figure 2 ] Figure 2 A second embodiment of the measuring device according to the invention is illustrated schematically in a functional manner.

[0020] [ Figure 3 ] Figure 3 An example of an electric machine according to the present invention is shown schematically.

[0021] [ Figure 4 ] Figure 4 An example of a battery according to the present invention is shown schematically.

[0022] [ Figure 5 ] Figure 5 An example of a battery pack according to the present invention is shown schematically.

[0023] [ Figure 6 ] Figure 6 An example of a fuel cell according to the present invention is illustrated schematically.

[0024] [ Figure 7 ] Figure 7 An embodiment of the method according to the present invention is illustrated schematically. [Detailed Implementation] Figure 1 This is an example of a measuring device 1 according to the present invention. Device 1 is intended to be installed in a motor vehicle.

[0025] Device 1 includes a main module 10 and a remote module 20.

[0026] Main Module 10 The main module 10 includes a control stage 110 and a main piezoelectric transceiver 120.

[0027] The control stage 110 is configured to power the main piezoelectric transceiver 120 and command the main piezoelectric transceiver 120 to transmit an ultrasonic signal, preferably at the resonant frequency of the main piezoelectric transceiver 120.

[0028] The main piezoelectric transceiver 120 is configured to transmit and receive an ultrasonic signal called the “power” signal SUA in order to power the remote module 20.

[0029] Preferably, the main piezoelectric transceiver 120 is configured to resonate at at least one predetermined frequency, preferably at two predetermined frequencies (e.g., 200 kHz and 2 MHz).

[0030] Remote Module 20 The remote module 20 includes a remote piezoelectric transceiver 210, a measurement stage 220, and a sensing element 230.

[0031] The remote piezoelectric transceiver 210 is configured to receive the ultrasonic power supply signal SUA emitted by the main piezoelectric transceiver 120 and transmit it to the measurement stage 220.

[0032] Preferably, the remote piezoelectric transceiver 210 is configured to resonate at at least one predetermined frequency, preferably at two predetermined frequencies (e.g., 200 kHz and 2 MHz).

[0033] The measuring stage 220 is connected to the remote piezoelectric transceiver 210 on one side and to the sensing element 230 on the other.

[0034] The measurement stage 220 is configured to collect and store the energy of the ultrasonic power signal SUA emitted by the remote piezoelectric transceiver 210, and to use the stored energy to power the sensing element 230.

[0035] Sensing element 230 is configured to measure parameters such as air temperature, air pressure, humidity, current intensity, mechanical force (stress), torque, etc.

[0036] It should be noted that the remote module 20 may include more than one sensing element 230 to measure multiple different parameters and / or multiple identical parameters at different locations.

[0037] Sensing element 230 is configured to generate a measurement signal S that includes one or more values ​​of the parameter.

[0038] Measurement stage 220 is configured to receive a measurement signal S generated by sensing element 230, extract at least one value of a measured parameter from the received measurement signal S, and generate a pulse width modulation (PWM) signal whose duty cycle represents at least one value of the extracted measured parameter.

[0039] The remote piezoelectric transceiver 210 is configured to convert the received pulse width modulation (PWM) signal into an ultrasonic measurement signal SUM and transmit the ultrasonic measurement signal SUM to the main piezoelectric transceiver 120.

[0040] The control stage 110 is configured to determine the duty cycle of the ultrasonic measurement signal SUM received by the main piezoelectric transceiver 120 (which is the same as the duty cycle of the pulse width modulation (PWM) signal), and to determine at least one value of the measured parameter based on the determined duty cycle.

[0041] One or more parameter values ​​can be determined based on the duty cycle using a mapping table stored in the memory area of ​​control level 110. This table may be determined empirically in advance.

[0042] exist Figure 2 In another embodiment shown, the remote module 20 includes an external communication stage 240, and the measurement stage 220 is configured to command the transmission of a signal containing (extracted from the measurement signal S) the measured parameter value via the external communication stage 240, specifically to an entity outside the device 1. This transmission can be performed, for example, on a communication interface of the type known per se, such as Bluetooth, Wi-Fi, 5G, or RFID. In this case, the external communication stage 240 preferably includes a microcontroller that enables this transmission function.

[0043] Example of use of the measuring device according to the invention Example 1: Electric Machine 300 Figure 3An example of an electric motor 300 for a motor vehicle is shown. The electric motor 300 is configured to be installed in the vehicle to drive the wheels of the vehicle to rotate.

[0044] The electric motor 300 includes a stator 310, a rotor 320, and the device 1 as described above.

[0045] The main module 10 is mounted on the stator 310, and the remote module 20 is mounted on the rotor 320.

[0046] The rotor 320 is configured to rotate about the longitudinal axis X.

[0047] In this example, the rotor 320 includes an integral shaft 321 that extends along the rotational longitudinal axis X and includes a first shaft portion 321A and a second shaft portion 321B that are connected to the stator 310 via a bearing system 315.

[0048] The first shaft portion 321A includes an end face 321A1 extending orthogonally to the longitudinal axis of rotation X of the rotor 320. A remote piezoelectric transceiver 210, a measuring stage 220, and a sensing element are mounted inside the rotor 320, and a main piezoelectric transceiver 120 is mounted on the portion of the stator 310 facing the end face 321A1.

[0049] Example 2: Battery 400 Figure 4 This is an example of a battery 400 used in motor vehicles.

[0050] The main module 10 is placed away from the battery 400, while the remote module 20 is installed on the battery 400, so that the sensing element 230 measures parameters inside the battery 400, such as temperature or pressure, humidity, current intensity, mechanical force (stress), torque, etc.

[0051] It should be noted that the remote piezoelectric transceiver 210 and the measuring stage 220 can be mounted on the external surface of the battery 400, or mounted inside the battery 400 together with the sensing element 230, as in Example 1 of the electric machine 300.

[0052] Example 3: Battery pack 500 Figure 5 This is an example of a battery pack 500 used in motor vehicles.

[0053] The main module 10 is placed away from the battery pack 500, while one or more remote modules 20 are respectively mounted on one or more batteries 400 of the battery pack 500, such that the sensing element 230 of each remote module 20 measures parameters inside each battery 400, such as temperature or pressure.

[0054] Example 4: Fuel Cell 600 Figure 6 This is an example of a fuel cell 600 used in motor vehicles.

[0055] The main module 10 is placed away from the fuel cell 600, while the remote module 20 is mounted on the fuel cell 600, allowing the sensing element 230 to measure parameters inside the fuel cell 600, such as in the circuit used to supply air to the membrane of the fuel cell 600. Again, one or more of the measured parameters may be, for example, temperature, pressure, humidity, current intensity, mechanical force (stress), or torque.

[0056] Examples of implementation methods Now refer to Figure 7 An example of an implementation of the device 1 is described. In this non-limiting example, the parameter to be measured may be, for example, temperature, particularly the temperature inside the rotor 320 of the electric machine 300.

[0057] First, when parameters need to be measured, in step E1, the control level 110 of the main module 10 commands the main piezoelectric transceiver 120 to transmit an ultrasonic power supply signal SUA, preferably at one of the resonant frequencies, to improve the transmission quality of the ultrasonic power supply signal SUA.

[0058] In step E2, the main piezoelectric transceiver 120 transmits an ultrasonic power supply signal SUA, which is received by the remote piezoelectric transceiver 210 and transmitted to the measurement stage 220 in step E3.

[0059] In step E4, the measuring stage 220 collects and stores the energy of the ultrasonic power supply signal SUA, and then uses the stored energy to power the sensing element 230 in step E5.

[0060] Once powered, the sensing element 230 measures the parameter of interest in step E6, which may be, for example, air temperature, air pressure, humidity, current intensity, mechanical force (stress), or torque.

[0061] During parameter measurement, the sensing element 230 generates a measurement signal S in step E7, which includes one or more values ​​of the parameter being measured, and then transmits the generated measurement signal S to the measurement stage 220 in step E8.

[0062] In step E9, measurement stage 220 receives the transmitted measurement signal S, and then in step E10 extracts one or more values ​​of the measured parameter contained in the received measurement signal S.

[0063] Then, in step E11, the measurement stage 220 generates a pulse width modulation (PWM) signal whose duty cycle represents at least one value of the extracted measured parameter. Specifically, when measuring multiple different values, the duty cycle varies according to those values. For example, a 25% duty cycle may correspond to a temperature of 30°C, a 50% duty cycle may correspond to a temperature of 50°C, and a 75% duty cycle may correspond to a temperature of 70°C.

[0064] Then, in step E12, the remote piezoelectric transceiver 210 converts the received pulse width modulation (PWM) signal into an ultrasonic measurement signal SUM, which is then transmitted by the remote piezoelectric transceiver 210 to the main piezoelectric transceiver 120 in step E13.

[0065] The ultrasonic measurement signal SUM is received by the main piezoelectric transceiver 120 and transmitted to the control stage 110, which determines the duty cycle of the received ultrasonic measurement signal SUM in step E14.

[0066] Finally, in step E15, control level 110 determines at least one value of the measured parameter based on the determined duty cycle, for example, based on a predetermined correspondence table stored in its memory area.

[0067] Therefore, the present invention enables the measurement of parameters using a remotely powered remote module 20, thereby avoiding the use of replaceable batteries, which is particularly advantageous in the case of the rotor of an electric machine.

Claims

1. An apparatus (1) for measuring parameters of a motor vehicle, the apparatus (1) comprising a main module (10) and a remote module (20), the main module (10) comprising a control stage (110) and a main piezoelectric transceiver (120) configured to transmit an ultrasonic power supply signal (SUA), the control stage (110) configured to power the main piezoelectric transceiver (120) and command the main piezoelectric transceiver (120) to transmit the ultrasonic power supply signal (SUA), the remote module (20) comprising: A remote piezoelectric transceiver (210) configured to receive the ultrasonic power supply signal (SUA) emitted by the main piezoelectric transceiver (120); a sensing element (230) configured to measure the parameter and generate a measurement signal (S) including at least one value of the parameter; and a measurement stage (220) connected on one side to the remote piezoelectric transceiver (210) and on the other side to the sensing element (230), and configured to collect and store the energy of the ultrasonic power supply signal received by the remote piezoelectric transceiver (210), use the stored energy to power the sensing element (230), and receive the measurement signal (S) generated by the sensing element (230). The remote piezoelectric transceiver (210) is configured to convert the received pulse width modulation (PWM) signal into an ultrasonic measurement signal (SUM) and transmit the ultrasonic measurement signal (SUM) to the main piezoelectric transceiver (120). The control stage (110) is configured to determine the duty cycle of the ultrasonic measurement signal (SUM) received by the main piezoelectric transceiver (120), the duty cycle of the ultrasonic measurement signal being the same as the duty cycle of the pulse width modulation (PWM) signal, in order to determine at least one value of the measured parameter.

2. The apparatus (1) as claimed in claim 1, wherein, The main piezoelectric transceiver (120) and the remote piezoelectric transceiver (210) are configured to resonate at at least one given predetermined frequency, the control stage (110) is configured to generate a signal at the at least one predetermined frequency and transmit the generated signal to the main piezoelectric transceiver (120), and the measurement stage (220) is configured to generate a signal at the at least one predetermined frequency and transmit the generated signal to the remote piezoelectric transceiver (210).

3. The apparatus (1) as claimed in claim 1, wherein, The remote module (20) includes an external communication stage (240), and the measurement stage (220) is configured to command the transmission of signals containing these measured values ​​via the external communication stage (240).

4. The apparatus (1) as described in any of the preceding claims, wherein, The control level (110) includes a memory region that stores a table, for example, predetermined based on experience, and the table contains a correspondence between the duty cycle and the range of values ​​for the parameter.

5. An electric motor (300) for a motor vehicle, the electric motor (300) comprising a stator (310), a rotor (320) and a device (1) as described in any of the preceding claims, the electric motor (300) being configured to be mounted in the vehicle to drive the wheels of the vehicle to rotate, wherein the main module (10) is mounted on the stator (310) and the remote module (20) is mounted on the rotor (320).

6. The electric machine (300) as claimed in the preceding claim, wherein, The remote module (20) is installed inside the rotor (320).

7. The electric machine (300) as claimed in any one of claims 5 and 6, wherein, The rotor (320) includes a shaft (321) comprising a first shaft portion (321A) and a second shaft portion (321B) mounted on the stator (310) via a bearing system (315). The first shaft portion (321A) includes an end face (321A1) extending orthogonally to the longitudinal axis (X) of rotation of the rotor (320). The remote piezoelectric transceiver (210) is mounted on the end face (321A1), and the main piezoelectric transceiver (120) is mounted on the portion of the stator (310) facing the remote piezoelectric transceiver (210).

8. A battery (400) or battery pack (500) or fuel cell (600) for a motor vehicle, the battery or battery pack or fuel cell including a measuring device (1) as claimed in any one of claims 1 to 4, the remote module (20) being mounted such that the sensing element (230) is correspondingly placed inside the battery (400), or inside at least one battery (400) of the battery pack (500), or inside the fuel cell (600).

9. A motor vehicle comprising a measuring device (1) as claimed in any one of claims 1 to 4.

10. A method for measuring parameters in a motor vehicle using the measuring device (1) as described in any one of claims 1 to 4, the method comprising the following steps: - The control level (110) commands (E1) to transmit an ultrasonic power supply signal (SUA) from the main piezoelectric transceiver (120). - The ultrasonic power supply signal (SUA) is transmitted (E2) by the main piezoelectric transceiver (120). - The ultrasonic power supply signal (SUA) transmitted by the remote piezoelectric transceiver (210) is received by (E3). - The energy of the ultrasonic power supply signal (SUA) is collected and stored (E4) by the measuring stage (220). - The measuring stage (220) uses the stored energy to power the sensitive element (230) (E5). - This parameter is measured (E6) by the sensitive element (230). - A measurement signal (S) including at least one value of the measured parameter is generated by the sensing element (230) (E7). - The generated measurement signal (S) is transmitted (E8) to the measurement stage (220) by the sensitive element (230). - The measurement signal (S) is received (E9) by the measurement stage (220). - At least one value of the measured parameter contained in the measurement signal (S) received by the measurement stage (220) (E10), - A pulse width modulation (PWM) signal, whose duty cycle represents at least one value of the extracted measured parameter, is generated by the measurement stage (220) (E11). The received pulse width modulation (PWM) signal is converted (E12) into an ultrasonic measurement signal (SUM) by the remote piezoelectric transceiver (210). The ultrasonic measurement signal (SUM) is transmitted (E13) from the remote piezoelectric transceiver (210) to the main piezoelectric transceiver (120). - The duty cycle of the ultrasonic measurement signal (SUM) received by the control level (110) (E14) is determined. - The control level (110) determines at least one value of the parameter measured by (E15) based on the determined duty cycle.

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