Pulse width modulation (PWM) signal modulation circuit and thermal management system

Abstract

The utility model discloses a pulse width modulation (PWM) signal modulation circuit and a thermal management system. The circuit comprises a first filtering module, the first end of which is used for receiving the PWM signal; the first end of the high-voltage protection module is connected with the second end of the first filtering module; the first end of the voltage conversion module is connected with the second end of the high-voltage protection module, and the second end of the voltage conversion module is used for outputting a modulated PWM signal. According to the embodiment of the invention, the input PWM signal is subjected to filtering, high-voltage protection and voltage reduction processing through the first filtering module, the high-voltage protection module and the voltage conversion module, so that modulation of the PWM signal is realized through a simple circuit structure, and the hardware cost in the PWM signal modulation process is reduced.

Description

Technical Field

[0001] The present application belongs to the field of automobile control technology, and in particular relates to a pulse width modulation (PWM) signal modulation circuit and a thermal management system. Background Art

[0002] In new energy vehicles, heat dissipation of the battery pack is crucial. To achieve heat dissipation management of the battery pack, the water pump can be precisely controlled by the thermal management control system in the new energy vehicle to change the flow and distribution of the coolant, thereby achieving temperature regulation of the battery pack. Therefore, determining the working state of the water pump is the basis for battery pack temperature regulation.

[0003] In the related art, the controller of the water pump can perform self-checking to determine the working state of the water pump, and feed back the corresponding state information of the water pump to the thermal management control system, so that the thermal management control system can determine the working state of the water pump. Furthermore, the water pump state information fed back by the water pump controller to the thermal management control system can be reflected by different pulse width modulation (PWM) signals.

[0004] When the water pump controller sends a PWM signal to the thermal management control system, the PWM signal needs to be modulated to ensure that the thermal management control system can receive a stable PWM signal with low noise, so as to determine and obtain the water pump status information. However, in the related art, the modulation circuit structure of the PWM signal is relatively complex, the design is difficult, and the cost is high. Therefore, how to realize the modulation of the PWM signal with a circuit with a simple structure and low cost has become a technical problem that needs to be solved urgently by related technical personnel. Utility Model Content

[0005] The embodiments of the present application provide a pulse width modulation (PWM) signal modulation circuit and a thermal management system, which can realize the modulation of the PWM signal with a circuit having a simple structure and low cost.

[0006] In a first aspect, an embodiment of the present application provides a pulse width modulation (PWM) signal modulation circuit, comprising: a first filtering module, wherein the first end of the first filtering circuit is used to receive a PWM signal; a high-voltage protection module, wherein the first end of the high-voltage protection module is connected to the second end of the first filtering module; and a voltage conversion module, wherein the first end of the voltage conversion module is connected to the second end of the high-voltage protection module, and the second end of the voltage conversion module is used to output a modulated PWM signal.

[0007] In one implementation, the first filtering module includes: a low-pass filtering circuit.

[0008] In one embodiment, the low-pass filter circuit includes: a first capacitor and a first inductor. The first end of the first inductor is configured to receive the PWM signal, the second end of the first inductor is connected to the high-voltage protection module, one end of the first capacitor is connected to the second end of the first inductor, and the other end of the first capacitor is grounded.

[0009] In one embodiment, the high-voltage protection module includes: a unidirectional cut-off module.

[0010] In one embodiment, the voltage conversion module includes: a voltage-dividing module, a first end of the voltage-dividing module is connected to the high-voltage protection module, a second end of the voltage-dividing module is connected to a first end of the switching module, and a third end of the voltage-dividing module is connected to the first power module; a switching module, a second end of the switching module is connected to the first power module, and a third end of the switching module is configured to output a modulated PWM signal.

[0011] In one embodiment, the voltage-dividing module includes a first voltage-dividing branch and a second voltage-dividing branch, and the switching module includes a transistor; one end of the first voltage-dividing branch is connected to the high-voltage protection module, the other end of the first voltage-dividing branch is connected to the control end of the transistor, one end of the second voltage-dividing branch is connected to the first power module, the other end of the second voltage-dividing branch is connected to the control end of the transistor, a first end of the transistor is connected to the first power module, a second end of the transistor is grounded, and the PWM signal output from the second end of the transistor is used as the modulated PWM signal.

[0012] In one embodiment, it further includes: a second power module and a third voltage-dividing module, one end of the third voltage-dividing module is connected to the second power module, and the other end of the third voltage-dividing module is connected to the first end of the high-voltage protection module.

[0013] In one embodiment, it further includes: a second filter circuit, one end of the second filter circuit is connected to the voltage conversion module, and the other end of the second filter circuit is configured to output a modulated PWM signal.

[0014] In one embodiment, the second filter circuit includes: a fourth resistor and a second capacitor, a first end of the fourth resistor is connected to the voltage conversion module, and a second end of the fourth resistor is configured to output a modulated PWM signal; one end of the second capacitor is connected to the second end of the fourth resistor, and the other end of the second capacitor is grounded.

[0015] In a second aspect, an embodiment of the present application provides a thermal management system, including: a water pump control module; a thermal management control module; a PWM signal modulation circuit according to the first aspect or any one of the embodiments of the first aspect, one end of the PWM signal modulation circuit is connected to the water pump control module, and the other end of the PWM signal modulation circuit is connected to the thermal management control module.

[0016] The pulse-width modulation (PWM) signal modulation circuit and thermal management system according to the embodiments of the present application perform filtering, high-voltage protection, and buck conversion on the input PWM signal through a first filtering module, a high-voltage protection module, and a voltage conversion module, thereby realizing the modulation of the PWM signal with a simple circuit structure and reducing the hardware cost during the PWM signal modulation process. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0018] Figure 1 FIG. shows a schematic structural diagram of a PWM signal modulation circuit provided by an embodiment of the present application;

[0019] Figure 2 FIG. shows a schematic structural diagram of a PWM signal modulation circuit provided by an embodiment of the present application;

[0020] Figure 3 FIG. shows a schematic structural diagram of another PWM signal modulation circuit provided by an embodiment of the present application;

[0021] Figure 4 FIG. shows a schematic structural diagram of yet another PWM signal modulation circuit provided by an embodiment of the present application;

[0022] Figure 5 FIG. shows a schematic structural diagram of a PWM signal modulation circuit provided by an embodiment of the present application;

[0023] Figure 6 FIG. shows an architecture diagram of a thermal management system provided by an embodiment of the present application. Detailed Embodiments

[0024] The features and exemplary embodiments of various aspects of the present application will be described in detail below. To make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application and not to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present application by showing examples of the present application.

[0025] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0026] With the rapid development of the social economy and the continuous progress of new energy technologies, new energy vehicles have gradually become an essential tool in people's daily lives. There is a battery pack in a new energy vehicle. During the charging and discharging process of the battery pack, a large amount of heat will be generated. If these heats cannot be dissipated in a timely and effective manner, it will cause the battery pack to overheat, affect the battery performance, and even may lead to major safety problems. Therefore, the heat dissipation problem of the battery pack is one of the important problems in the thermal management system of new energy vehicles.

[0027] To solve the heat dissipation problem of the battery pack, the thermal management controller in the thermal management system precisely controls the water pump to change the flow direction and distribution of the coolant, so as to achieve the regulation of the battery pack temperature. It can be understood that when it is determined that the temperature of the battery pack exceeds the preset safety threshold, the thermal management controller controls the water pump to start, so that the coolant passes through the cooling channels inside the battery pack, so that the coolant washes away the heat generated by the battery pack and takes away these heats, realizing the cooling of the battery pack.

[0028] In the related art, to ensure the stability and reliability during the operation of the water pump, the controller of the water pump will perform self-check in real time. Through the self-check of the water pump controller, the working state of the water pump and various related parameters, such as temperature, pressure, flow rate, etc., are determined. When the controller of the water pump determines any abnormality or the parameter deviates from the predetermined parameter range, it will automatically trigger the alarm mechanism. At this time, the controller of the water pump will send a fault report to the thermal management controller through a Pulse Width Modulation (PWM) signal. Among them, the PWM signal is an efficient and commonly used communication method, which can transmit different information by adjusting the width and frequency of the pulse, including the type and severity of the fault.

[0029] In the related art, an operational amplifier or a comparator is usually used to condition the input PWM signal. Generally, a limiting circuit is first used to reduce the voltage of the input signal and limit the maximum amplitude of the signal to prevent excessive voltage from damaging the subsequent circuit. Further, in order to make the PWM signal more stable and isolated from the previous-stage circuit, an active voltage follower circuit composed of an operational amplifier is used to improve the driving ability of the signal. The PWM signal processed through the foregoing steps is sent to a comparator, and a standardized PWM signal is output. Finally, the standardized PWM signal flows to a thermal management controller, and the thermal management controller analyzes based on the received PWM signal to determine the operating state of the water pump.

[0030] However, the operational amplifier or comparator used for PWM signal modulation often has a complex structure and requires multiple components and precise design to achieve the expected function. This complexity not only increases the design difficulty but also leads to an increase in cost. In addition, high temperature often affects the operating characteristics of the operational amplifier, including its gain, bandwidth, and noise performance, etc., which may cause the output of the circuit to deviate from the expectation, thereby affecting the control accuracy and stability of the entire thermal management system.

[0031] To solve the problems of the prior art, the embodiments of the present application provide a pulse width modulation (PWM) signal modulation circuit and a thermal management system. First, the PWM signal modulation circuit provided by the embodiments of the present application will be introduced below.

[0032] Figure 1 The structural schematic diagram of the PWM signal modulation circuit provided by an embodiment of the present application is shown. As Figure 1 shown, the PWM signal modulation circuit 100 includes:

[0033] A first filtering module 110, the first end of the first filtering module 110 is used to receive the PWM signal;

[0034] A high-voltage protection module 120, the first end of the high-voltage protection module 120 is connected to the second end of the first filtering module 110;

[0035] A voltage conversion module 130, the first end of the voltage conversion module 130 is connected to the second end of the high-voltage protection module 120, and the second end of the voltage conversion module 130 is used to output the modulated PWM signal.

[0036] In the embodiments of the present application, the first filtering module is used to filter out high-frequency noise signals in the PWM signal. After the PWM signal is input to the first filtering module, the filtering of high-frequency noise can be achieved through the first filtering module, thereby avoiding the interference of high-frequency noise on the subsequent circuit.

[0037] In the embodiment of the present application, the first filtering module may be a low-pass filtering circuit. It can be understood that the low-pass filtering circuit can filter out high-frequency noise in the PWM signal and allow low-frequency signals and DC signals to pass through, ensuring the integrity of the PWM signal.

[0038] In the embodiment of the present application, the low-pass filtering circuit may be a capacitor-inductor (LC) filtering circuit. And the LC filtering circuit may include a first capacitor and a first inductor. Wherein, the first end of the first inductor is used to receive the PWM signal, the second end of the first inductor is connected to the high-voltage protection module, one end of the first capacitor is connected to the second end of the first inductor, and the other end of the first capacitor is grounded.

[0039] It can be understood that the inductor and capacitor in the LC filtering circuit have a good blocking effect on the high-frequency signals in the PWM signal, so that the high-frequency components in the PWM signal can be effectively suppressed or filtered out. Thereby, it helps to reduce the noise and harmonic components in the signal and improve the purity of the PWM signal. And the LC filtering circuit has a small blocking effect on the low-frequency signals or DC signals in the PWM signal, so as to ensure that the low-frequency and DC components in the PWM signal are retained.

[0040] In the embodiment of the present application, the first filtering module may also be other circuits capable of filtering out high-frequency signals, and specific examples are not listed here one by one in the embodiment of the present application.

[0041] In the embodiment of the present application, the high-voltage protection module includes a unidirectional cutoff module. It can be understood that in the case of a high voltage in the circuit, the unidirectional cutoff module can ensure that the voltage flowing into the subsequent circuit is not too high, causing damage to other electronic devices in the circuit. In one example, the unidirectional cutoff module may include a reverse diode or a Zener diode. Under normal circumstances, that is, when there is no excessive voltage in the circuit, the reverse diode is in the cutoff state, and the reverse diode has little influence on the transmission of the PWM signal, that is, the PWM signal can pass through the reverse diode normally. When a high voltage (reaching the breakdown voltage of the reverse diode) appears in the circuit, the reverse diode is broken down, and due to the characteristics of the reverse diode, the high voltage can be clamped within a specific range, thereby preventing the high voltage from affecting the subsequent circuit. In addition, since the diode has a very high impedance in reverse bias, it can prevent high-frequency noise signals in the PWM from passing through, thereby improving the stability and reliability of the entire circuit.

[0042] In the embodiment of the present application, the voltage conversion module 130 is used to adjust the voltage of the filtered PWM signal, so that the PWM signal output through the voltage conversion module can be received by other electronic devices.

[0043] In the embodiment of the present application, Figure 2The structural schematic diagram of the PWM signal modulation circuit provided by an embodiment of the present application is shown. As Figure 2 shown, the voltage conversion module 130 includes:

[0044] A voltage dividing module 131, the first end of the voltage dividing module 131 is connected to the high-voltage protection module 120, the second end of the voltage dividing module 131 is connected to the first end of the switch module 133, and the third end of the voltage dividing module 131 is connected to the first power supply module 132;

[0045] A switch module 133, the second end of the switch module 133 is connected to the first power supply module 132, and the third end of the switch module 133 is used to output the modulated PWM signal.

[0046] In an embodiment of the present application, the first power supply module is divided by the voltage dividing module, so as to ensure that the switch module connected to the first power supply module can work normally.

[0047] In an embodiment of the present application, the voltage dividing module includes a first voltage dividing branch and a second voltage dividing branch, and the voltage division of the first end of the switch module is realized through the first voltage dividing branch and the second voltage dividing branch.

[0048] In an embodiment of the present application, the first power supply module is used to supply power to the switch module, so as to ensure the normal operation of the switch module. In one example, the first power supply module may be a DC power supply with a voltage value of 5 volts (V) to supply power to the switch module.

[0049] In an embodiment of the present application, the switch module is used to step down the PWM signal to ensure that the stepped-down PWM signal can be received by other electronic devices.

[0050] In an embodiment of the present application, the switch module includes a transistor. And, one end of the first voltage dividing branch is connected to the high-voltage protection module, the other end of the first voltage dividing branch is connected to the control end of the transistor, one end of the second voltage dividing branch is connected to the first power supply module, the other end of the second voltage dividing branch is connected to the control end of the transistor, the first end of the transistor is connected to the first power supply module, the second end of the transistor is grounded, and the PWM signal output from the second end of the transistor is used as the modulated PWM signal.

[0051] In one example, the first voltage dividing branch may include a first resistor, the second voltage dividing branch may include a second resistor, and the transistor may be a PNP type triode. Moreover, one end of the first resistor may be connected to the high-voltage protection module, and the other end of the first resistor may be connected to the base of the triode. One end of the second resistor may be connected to the first voltage source, and the other end of the second resistor may be connected to the base of the triode. Also, the emitter of the transistor is connected to the first voltage source, and the collector of the triode is grounded. Before grounding the collector, a resistor may be connected in series to prevent the emitter and collector of the triode from directly conducting to the ground terminal. Further, through the voltage division of the first resistor and the second resistor, the base voltage of the triode is made lower than the emitter voltage. At this time, the triode can be regarded as a conducting switching device. When the PWM signal is at a high level, the base voltage includes the voltage division of the first power supply voltage and the high-level voltage of the PWM signal. At this time, the triode is in a cut-off state and can be regarded as an open switch, and the output voltage of the collector is 0. When the PWM signal is at a low level, the voltage of the base includes the voltage division of the first power supply voltage and the low-level voltage of the PWM signal. At this time, the base voltage is lower than the emitter voltage, and the triode is in a conducting state and can be regarded as a closed switch. At this time, the collector outputs a low voltage. It can be understood that through the triode, the high-level signal of the PWM signal is converted into a signal with a voltage of 0, and the low-level signal of the PWM signal is converted into a low-voltage signal. Moreover, the frequency of the PWM signal remains unchanged with the duty cycle, ensuring that the information contained in the PWM signal remains unchanged.

[0052] To ensure the applicability of the PWM modulation circuit, as another implementation manner of the present application, the present application also provides another implementation manner of the PWM signal modulation circuit. For details, refer to the following embodiments. Moreover, the another implementation manner of the PWM signal modulation circuit can be used alone or in combination with any of the above embodiments.

[0053] Please refer to Figure 3 , Figure 3 which shows a schematic structural diagram of another PWM signal modulation circuit provided by an embodiment of the present application. The PWM signal modulation circuit further includes a second power supply module 141 and a third voltage dividing module 142. One end of the third voltage dividing module 142 is connected to the second power supply module 141, and the other end of the third voltage dividing module 142 is connected to the first end of the high-voltage protection module 120.

[0054] In the embodiment of the present application, the second power supply module 141 and the third voltage dividing module 142 form a floating input protection circuit. Through the voltage provided by the second power supply module, when the PWM signal input is floating, the switch module is prevented from conducting, thus avoiding circuit failures. In one example, the second power supply voltage may be 24V.

[0055] In the embodiments of the present application, the second power supply module and the third voltage dividing module are used to prevent the circuit from malfunctioning when the PWM signal input is floating.

[0056] To ensure the stability of the modulated PWM signal, as another implementation manner of the present application, the present application also provides another implementation manner of the PWM signal modulation circuit. For details, please refer to the following embodiments. Moreover, the another implementation manner of the PWM signal modulation circuit can be used alone or in combination with any of the above embodiments.

[0057] Please refer to Figure 4 , Figure 4 FIG. shows a schematic structural diagram of another PWM signal modulation circuit provided by an embodiment of the present application. The PWM signal modulation circuit further includes a second filter circuit 150. One end of the second filter circuit is connected to the voltage conversion module 130, and the other end of the second filter circuit 150 is used to output the modulated PWM signal.

[0058] In the embodiments of the present application, the modulated PWM signal can be filtered by the second filter circuit, thereby reducing the noise of the modulated PWM signal and making the modulated PWM signal smoother.

[0059] In the embodiments of the present application, the second filter circuit may include a resistor-capacitor (RC) filter circuit. The second filter circuit may include a fourth resistor and a second capacitor. The first end of the fourth resistor is connected to the voltage conversion module, and the second end of the fourth resistor is used to output the modulated PWM signal; one end of the second capacitor is connected to the second end of the fourth resistor, and the other end of the second capacitor is grounded.

[0060] In the embodiments of the present application, the second filter circuit composed of the fourth resistor and the second capacitor can filter the modulated PWM signal to ensure the stability of the output PWM signal.

[0061] In the embodiments of the present application, in combination with Figure 5 and the following examples, the PWM signal modulation circuit will be described.

[0062] Figure 5 FIG. shows a schematic structural diagram of a PWM signal modulation circuit provided by an embodiment of the present application, as Figure 5As shown, after the PWM signal flows into the PWM signal modulation circuit, it first passes through the LC filter circuit composed of capacitor L1 and capacitor C1 to filter out the high-frequency interference signals in the PWM signal. Further, the filtered PWM signal flows through the reverse diode D1. Among them, the reverse diode D1 is used to prevent the high-voltage signals in the circuit from damaging other components in the circuit. Further still, the PWM signal flows into the voltage conversion module composed of resistor R1, resistor R2, PNP transistor Q1, and resistor R3 to convert the PWM signal into a PWM signal at a low voltage. The PWM signal modulation circuit further includes an RC filter circuit composed of resistor R4 and capacitor C2, which is used to filter the modulated PWM signal.

[0063] Further, when the PWM signal modulation circuit does not receive the PWM signal, that is, when the PWM signal is floating, by adding a voltage source and resistor R5 in front of the reverse diode D1, the conduction of the base of the transistor Q1 is avoided, thereby preventing the failure of the PWM signal modulation circuit.

[0064] Based on the PWM signal modulation circuit provided in the above embodiments, the present application also provides a specific implementation manner of a thermal management system. Please refer to the following embodiments.

[0065] First, refer to Figure 6 , Figure 6 FIG. shows the architecture diagram of a thermal management system provided by an embodiment of the present application. The thermal management system 600 provided by the embodiment of the present application includes the following units:

[0066] A water pump control module 610; a thermal management control module 620; the PWM signal modulation circuit 100 in any one of the above embodiments, one end of the PWM signal modulation circuit is connected to the water pump control module, and the other end of the PWM signal modulation circuit is connected to the thermal management control module.

[0067] Among them, the water pump control module 610 is used to self-check the working state of the water pump and send a PWM signal representing the water pump state to the thermal management control module 620.

[0068] In the embodiment of the present application, the thermal management control module 620 is used to receive the PWM signal sent by the water pump control module 610 and determine the working state of the water pump based on the received PWM signal, so as to determine the heat dissipation situation of the battery pack.

[0069] In the embodiment of the present application, the PWM signal modulation circuit is used to modulate the PWM signal output by the water pump control module 610, so as to ensure that the modulation of the PWM signal is achieved with a simple and effective circuit.

[0070] In the embodiments of the present application, the thermal management system uses a PWM signal modulation circuit to build a PWM signal modulation circuit at low cost while ensuring that the thermal management control module can obtain a suitable PWM signal, thus ensuring the stability of the thermal management system.

[0071] It should also be noted that the exemplary embodiments described in the present application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above steps. That is, the steps can be executed in the order mentioned in the embodiments, or different from the order in the embodiments, or several steps can be executed simultaneously.

[0072] As mentioned above, the foregoing is only the specific implementation manner of the present application. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be repeated here. It should be understood that the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present application.

Claims

1. A pulse width modulation (PWM) signal modulation circuit, characterized in that: include: A first filtering module, wherein a first end of the first filtering module is used to receive the PWM signal; A high voltage protection module, wherein a first end of the high voltage protection module is connected to a second end of the first filtering module; A voltage conversion module, wherein a first end of the voltage conversion module is connected to a second end of the high voltage protection module, and the second end of the voltage conversion module is used to output a modulated PWM signal.

2. The PWM signal modulation circuit according to claim 1, characterized in that: The first filtering module comprises: Low pass filter circuit.

3. The circuit according to claim 2, characterized in that The low-pass filtering circuit comprises: A first capacitor and a first inductor, wherein the first end of the first inductor is used to receive the PWM signal, the second end of the first inductor is connected to the high-voltage protection module, one end of the first capacitor is connected to the second end of the first inductor, and the other end of the first capacitor is grounded.

4. The PWM signal modulation circuit according to claim 1, characterized in that: The high voltage protection module comprises: One-way cut-off module.

5. The PWM signal modulation circuit according to claim 1, characterized in that: The voltage conversion module comprises: A voltage dividing module, wherein a first end of the voltage dividing module is connected to the high voltage protection module, a second end of the voltage dividing module is connected to a first end of the switch module, and a third end of the voltage dividing module is connected to a first power supply module; A switch module, a second end of the switch module is connected to the first power module, and a third end of the switch module is used to output the modulated PWM signal.

6. The circuit according to claim 5, characterized in that The voltage dividing module includes a first voltage dividing branch and a second voltage dividing branch, and the switch module includes a transistor; One end of the first voltage-dividing branch is connected to the high-voltage protection module, and the other end of the first voltage-dividing branch is connected to the control end of the transistor; one end of the second voltage-dividing branch is connected to the first power supply module, and the other end of the second voltage-dividing branch is connected to the control end of the transistor. The first end of the transistor is connected to the first power supply module, the second end of the transistor is grounded, and the PWM signal output by the second end of the transistor is used as the modulated PWM signal.

7. The PWM signal modulation circuit according to claim 1, characterized in that: Also includes: A second power supply module and a third voltage divider module, one end of the third voltage divider module is connected to the second power supply module, and the other end of the third voltage divider module is connected to the first end of the high voltage protection module.

8. The PWM signal modulation circuit according to claim 1, characterized in that: Also includes: A second filtering circuit, one end of the second filtering circuit is connected to the voltage conversion module, and the other end of the second filtering circuit is used to output the modulated PWM signal.

9. The circuit according to claim 8, characterized in that The second filtering circuit comprises: A fourth resistor and a second capacitor, wherein a first end of the fourth resistor is connected to the voltage conversion module, and a second end of the fourth resistor is used to output the modulated PWM signal; one end of the second capacitor is connected to the second end of the fourth resistor, and the other end of the second capacitor is grounded.

10. A thermal management system, characterized in that: The system comprises: Water pump control module; Thermal management control module; The PWM signal modulation circuit according to any one of claims 1 to 9, wherein one end of the PWM signal modulation circuit is connected to the water pump control module, and the other end of the PWM signal modulation circuit is connected to the thermal management control module.

Images