Brushless fan assembly adaptive to brush motor control mode and automobile cooling system

Abstract

The invention provides a brushless fan assembly adaptive to a brush control mode and an automobile cooling system. The brushless fan assembly comprises a brushless fan unit, a brush control unit and a control unit, the compatible interface unit is matched with an input interface unit of an original brush fan assembly of the automobile so as to receive the gear control signal; the gear identification unit responds to the gear control signal and outputs a corresponding gear identification signal; and the brushless control unit is respectively connected with the gear identification unit and the brushless fan unit, responds to the gear identification signal and generates a corresponding driving signal so as to control the brushless fan unit to operate at a target operation gear corresponding to the brush fan assembly. According to the technical scheme, on the premise that an original automobile cooling control unit and control logic thereof are not changed at all and original automobile wire harnesses are not changed, direct replacement and plug-and-play of the brushless fan assembly with better performance to the brush fan assembly are achieved, the requirement for convenience of automobile after-sale maintenance is met, and after-sale maintenance cost and operation difficulty are reduced.

Description

Adapted for brushless fan assemblies and automotive cooling systems with brushed motor control. Technical Field

[0001] This invention relates to the field of automotive cooling technology, and in particular to a brushless fan assembly and automotive cooling system adapted to a brush control method. Background Technology

[0002] Brushed DC motors are widely used in automotive cooling fans due to their simple structure, convenient control, and low cost. Currently, the vast majority of cooling fans in traditional gasoline-powered vehicles are driven by brushed motors. However, brushed motors have the following drawbacks: First, brushed motors rely on the mechanical contact between the brushes and the commutator to achieve current commutation. Long-term operation leads to brush wear, limiting their lifespan and increasing maintenance costs for users. Second, the mechanical friction between the brushes and the commutator can generate commutation sparks, posing a safety hazard in certain environments. In addition, brushed motors require a series power resistor for voltage reduction when operating at low speeds. The resistor generates significant heat, leading to energy waste, low system efficiency, increased generator load, and higher vehicle fuel consumption.

[0003] Brushless DC motors utilize electronic commutation technology, eliminating brushes and commutators. They offer significant advantages such as long lifespan, high efficiency, low electromagnetic interference, and quiet operation, making them an ideal replacement for brushed motors. However, for established products, such as those used in automotive aftermarket repair, directly replacing the original brushed fan assembly with a brushless one presents the following technical challenges: the original vehicle's cooling control unit and its control logic are designed for brushed motors, and their output speed control signals (such as voltage changes achieved through relay switching) cannot directly drive a brushless motor; brushless motors require a dedicated electronic controller and specific drive signals to function properly. Modifying the original vehicle's wiring harness or modifying the original control unit's program is not only costly and complex but also compromises the integrity and reliability of the original system, failing to meet aftermarket repair standards and customer expectations.

[0004] Therefore, the problem that needs to be solved is how to achieve a non-destructive replacement of the brushed fan assembly with the brushless fan assembly without changing the original vehicle's cooling control unit and its control logic, or without modifying the original vehicle's wiring harness. Summary of the Invention

[0005] In view of this, the present invention provides a brushless fan assembly and automotive cooling system adapted to a brush control method, so as to solve the problem of non-destructive replacement of a brushed fan assembly with a brushless fan assembly without changing the original vehicle cooling control unit and its control logic or modifying the original vehicle wiring harness.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: The present invention first provides a brushless fan assembly adapted to a brush control method, used to replace the original brushed fan assembly in a car. The car's cooling control unit controls different operating gears of the brushed fan assembly by outputting a gear control signal. The brushless fan assembly includes: a brushless fan unit; a compatible interface unit whose physical structure and electrical definition match the input interface unit of the brushed fan assembly, used to connect to the cooling control unit to receive the gear control signal; a gear identification unit whose input terminal is connected to the compatible interface unit, used to output a gear identification signal corresponding to the gear control signal in response to the gear control signal; and a brushless control unit, connected to both the gear identification unit and the brushless fan unit, used to generate a corresponding drive signal and output it to the brushless fan unit in response to the gear identification signal, so as to control the brushless fan unit to operate at a target operating gear corresponding to the brushed fan assembly.

[0007] In the specific solution, the gear control signal includes control signals with at least two different electrical states, each corresponding to a different operating gear of the original brushed fan assembly; the gear identification unit detects the electrical state of the gear control signal and outputs the corresponding gear identification signal.

[0008] In the specific scheme, the at least two different electrical states are at least two discrete voltage or current values.

[0009] In the specific solution, the gear position recognition unit includes a signal acquisition module and a signal processing module; the signal acquisition module is connected to the power circuit of the compatible interface unit and is used to acquire a sampled signal that characterizes the electrical state of the gear position control signal; the signal processing module is connected to the signal acquisition module and is used to process the sampled signal and output the gear position recognition signal.

[0010] In the specific solution, the signal acquisition module includes a sampling resistor, and the signal processing module includes a signal amplifier; the sampling resistor is connected to the power supply circuit of the compatible interface unit, the input terminal of the signal amplifier is connected to both ends of the sampling resistor, and the signal amplifier is used to amplify the voltage difference across the sampling resistor and output the amplified voltage signal as the gear identification signal.

[0011] In the specific solution, the signal acquisition module and the signal processing module are integrated in the Hall effect current sensor chip; the Hall effect current sensor chip is connected to the power supply circuit of the compatible interface unit to detect the current flowing through its internal conductive path, and outputs a corresponding voltage signal as the gear identification signal based on the current.

[0012] In the specific scheme, the gear control signal includes at least three control signals corresponding to the three electrical states of stop, low speed and high speed; the gear identification unit responds to the gear control signal and outputs a gear identification signal corresponding to the stop, low speed or high speed; the brushless control unit responds to the gear identification signal and controls the brushless fan unit to be in stop operation, low speed operation or high speed operation respectively.

[0013] In the specific solution, the brushless fan assembly is integrated into a separate housing, and the compatible interface unit is disposed on the housing to achieve a complete physical and electrical replacement of the original brushed fan assembly of the car.

[0014] In the specific solution, the brushless control unit includes a microcontroller and a brushless motor drive circuit; the microcontroller receives the gear identification signal from the gear identification unit and outputs a PWM signal with a corresponding duty cycle to the brushless motor drive circuit; the brushless motor drive circuit generates a corresponding drive signal based on the PWM signal and outputs it to the brushless fan unit to drive the brushless fan unit to run; the brushless motor drive circuit is a three-phase full-bridge inverter circuit.

[0015] The present invention also provides an automotive cooling system, which includes a cooling control unit and a brushless fan assembly as described above, wherein a compatible interface unit in the brushless fan assembly is electrically connected to the cooling control unit.

[0016] The brushless fan assembly and corresponding automotive cooling system provided in this invention, by setting a compatible interface unit that matches the input interface unit of the original brushed fan assembly, completely replicates the original vehicle interface in terms of physical structure and electrical definition. It can be directly plugged into the original vehicle wiring harness of the cooling control unit without any adapters or wiring modifications. Simultaneously, through a gear position recognition unit, the electrical state of the gear position control signal output by the original vehicle cooling control unit is identified, enabling the brushless control unit to accurately understand the original vehicle's gear position commands and control the brushless fan unit to operate at the corresponding target gear position. Therefore, the technical solution of this invention achieves a direct replacement of the brushed fan assembly with a higher-performance brushless fan assembly without changing the original vehicle cooling control unit and its control logic, or modifying the original vehicle wiring harness. This plug-and-play functionality meets the convenience requirements of automotive aftermarket maintenance, reducing aftermarket maintenance costs and operational complexity. Attached Figure Description

[0017] Figure 1 is a schematic diagram of an existing automotive cooling system; Figure 2 is a schematic diagram of the cooling control unit in the automotive cooling system shown in Figure 1; Figure 3 is a schematic diagram of an automotive cooling system according to an embodiment of the present invention; Figure 4 is a schematic diagram of a brushless fan assembly according to an embodiment of the present invention; Figure 5 is a circuit diagram of a gear position recognition unit according to an embodiment of the present invention; Figure 6 is a circuit diagram of a gear position recognition unit according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0019] In the following description, the expression “some embodiments” refers to a subset of all possible embodiments. However, it should be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0020] To facilitate understanding of the technical solution of the present invention, the specific structure and working process of an existing automotive cooling system will be described first. Figure 1 is a schematic diagram of an existing automotive cooling system 100, which mainly includes a cooling control unit 1 and a brushed fan assembly 2. The cooling control unit 1 controls the different operating speeds of the brushed fan assembly 2 by outputting a speed control signal.

[0021] Taking a typical two-speed control scheme as an example, as shown in Figures 1 and 2, the cooling control unit 1 includes a power supply 11, a first relay 12, a second relay 13, and a temperature control switch 14. The brushed fan assembly 2 is equipped with a speed control resistor Rp and a brushed fan unit 21, which includes a brushed motor and a fan impeller connected to the power output terminal of the brushed motor.

[0022] The power supply 11 has a positive terminal connected to a first positive power line 15 and a second positive power line 16, and a negative terminal connected to a negative power line 17. A first relay 12 is connected to the first positive power line 15, and a second relay 13 is connected to the second positive power line 16. A temperature control switch 14 is located in the cooling water tank 18 and is electrically connected to both the first relay 12 and the second relay 13. The brushed fan assembly 2 has an input interface unit 22, which connects the positive terminal of the brushed fan unit 21 to the first positive power line 15 and the second positive power line 16, and connects the negative terminal of the brushed fan unit 21 to the negative power line 17. A speed-regulating resistor Rp is connected in series between the input interface unit 22 and the positive terminal of the brushed fan unit 21 on the line corresponding to the first positive power line 15.

[0023] The working process is as follows: When the water temperature in the cooling water tank 18 is lower than the first threshold, the temperature control switch 14 controls the first relay 12 and the second relay 13 to be disconnected, and the brushed fan unit 21 has no voltage input and is in a stopped state; when the water temperature reaches the first threshold but is lower than the second threshold, the temperature control switch 14 controls the first relay 12 to be energized and the second relay 13 to be disconnected, and the voltage provided by the power supply 11 is input to the brushed fan unit 21 through the first positive power line 15 and the speed regulating resistor Rp. At this time, the speed regulating resistor Rp is connected in series with the brushed fan unit 21 to divide the voltage, and the voltage of the brushed fan unit 21 is relatively low and it operates at low speed; when the water temperature reaches the second threshold, the temperature control switch 14 controls the first relay 12 to be disconnected and the second relay 13 to be energized, and the voltage provided by the power supply 11 is directly input to the brushed fan unit 21 through the second positive power line 16, and the voltage of the brushed fan unit 21 is relatively high and it operates at high speed.

[0024] As mentioned above, based on the defects of brushed motors and the advantages of brushless motors, in the above-mentioned automotive cooling system 100, when the brushed fan assembly 2 is damaged and needs to be repaired or replaced, it is desirable to replace the brushed fan assembly 2 with a brushless fan assembly with a brushless motor without changing the cooling control unit 1 and its control logic or modifying the original vehicle wiring harness.

[0025] To achieve the above objectives, embodiments of the present invention provide a brushless fan assembly adapted to a brush control method and an automotive cooling system including the brushless fan assembly. Figure 4 is a structural diagram of the brushless fan assembly 3 in a specific embodiment of the present invention, and Figure 3 is a structural diagram of the automotive cooling system 200 in a specific embodiment of the present invention.

[0026] Referring to Figures 3 and 4 and in conjunction with Figure 2, the automotive cooling system 200 in this embodiment mainly includes a cooling control unit 1 and a brushless fan assembly 3. The cooling control unit 1 is the original cooling control unit 1 shown in Figure 2. The brushless fan assembly 3 mainly includes a brushless fan unit 31, a compatible interface unit 32, a gear position recognition unit 33, and a brushless control unit 34.

[0027] The brushless fan unit 31 includes a brushless motor and a fan impeller connected to the power output end of the brushless motor.

[0028] The physical structure and electrical definition of the compatible interface unit 32 are matched with the input interface unit 22 of the brushed fan assembly 2. It is used to connect to the original vehicle's cooling control unit 1 to receive the gear control signal output by the cooling control unit 1. Specifically, the compatible interface unit 32 includes a plug housing, terminal arrangement, and locking structure identical to the input interface unit 22 of the brushed fan assembly 2, enabling direct plug-in with the original vehicle wiring harness without any adapters or wiring modifications.

[0029] The input terminal of the gear position recognition unit 33 is connected to the compatible interface unit 32, and is used to respond to the gear position control signal and output a corresponding gear position recognition signal. In a specific embodiment, the gear position control signal includes control signals with at least two different electrical states (such as voltage value, current value, etc.), which respectively correspond to different operating gears of the original brushed fan assembly 2; the gear position recognition unit 33 identifies the electrical state of the gear position control signal and outputs a corresponding gear position recognition signal.

[0030] The brushless control unit 34 is connected to both the gear position recognition unit 33 and the brushless fan unit 31. The brushless control unit 34 responds to the gear position recognition signal and generates a corresponding drive signal according to a preset mapping relationship, outputting it to the brushless fan unit 31 to control the brushless fan unit 31 to operate at a target gear position corresponding to the brushed fan assembly 2.

[0031] Through the above-described structure, the technical solution of the present invention achieves non-destructive replacement of the brushed fan assembly 2 without altering the original vehicle cooling control unit 1 and its control logic, or modifying the original vehicle wiring harness. The gear control signal output by the original vehicle cooling control unit 1 is accurately recognized and understood by the gear recognition unit 33, and converted into the drive signal required by the brushless control unit 34, so that the brushless fan unit 31 operates according to the original vehicle's gear command.

[0032] In the specific scheme, the gear control signal includes control signals with at least two different electrical states, which correspond to different operating gears of the original brushed fan assembly; the gear identification unit 33 identifies the electrical state of the gear control signal and outputs the corresponding gear identification signal.

[0033] In some specific embodiments, the at least two different electrical states are at least two discrete voltage or current values. In a specific implementation, the gear control signal may itself contain at least two discrete voltage or current values; that is, depending on the gear position, the gear control signal has different voltage or current values ​​before being input to the compatible interface unit 32. Alternatively, the gear control signal may, after being input to the compatible interface unit 32, exhibit different voltage or current values ​​corresponding to different gear positions based on the specific connection circuit between the gear identification unit 33 and the compatible interface unit 32.

[0034] In some specific embodiments, the gear control signal includes at least three control signals corresponding to three electrical states: stop, low speed, and high speed. The gear identification unit 33 detects, identifies, and outputs a gear identification signal corresponding to the stop, low speed, or high speed. The brushless control unit 34 controls the brushless fan unit 31 to operate at stop, low speed, or high speed according to the gear identification signal.

[0035] In some specific embodiments, the specific circuit structures of the compatible interface unit 32, the gear position recognition unit 33, and the brushless control unit 34 are integrated on the same PCB board, and the operating voltage of the gear position recognition unit 33 and the brushless control unit 34 is provided by the compatible interface unit 32. For example, the compatible interface unit 32 is connected to a power conversion circuit, and the output terminal of the power conversion circuit is connected to the operating voltage pins of the gear position recognition unit 33 and the brushless control unit 34. When the compatible interface unit 32 receives power from the cooling control unit 1, the power conversion circuit converts the power supply voltage into the corresponding operating voltage and supplies it to the gear position recognition unit 33 and the brushless control unit 34, which then power on and enter the working state. When the compatible interface unit 32 has no power input, the gear position recognition unit 33 and the brushless control unit 34 are powered off and stop working.

[0036] In some specific embodiments, as shown in FIG4, the gear position recognition unit 33 includes a signal acquisition module 331 and a signal processing module 332. The signal acquisition module 331 is connected to the power supply circuit of the compatible interface unit 32 and is used to acquire a sampled signal characterizing the electrical state of the gear position control signal. The signal processing module 332 is connected to the signal acquisition module 331 and is used to process the sampled signal and output the gear position recognition signal.

[0037] In a preferred embodiment, as shown in Figures 4 and 5, in the gear position recognition unit 33, the signal acquisition module 331 includes a sampling resistor Rs, and the signal processing module 332 includes a signal amplifier U1. The sampling resistor Rs is connected to the power supply circuit of the compatible interface unit 32, and the input terminal of the signal amplifier U1 is connected to both ends of the sampling resistor Rs. The signal amplifier U1 is used to amplify the voltage difference across the sampling resistor Rs and output the amplified voltage signal as the gear position recognition signal. The signal amplifier U1 is, for example, an INA187 series current sensing amplifier chip.

[0038] Specifically, as shown in Figure 5, the first input terminal J1 represents the voltage input terminal connected to the first positive power line 15 in the compatible interface unit 32, the second input terminal J2 represents the voltage input terminal connected to the second positive power line 16 in the compatible interface unit 32, the first output terminal J3 represents the gear position recognition signal output terminal connected to the brushless control unit 34, and the second output terminal J4 represents the DC voltage output terminal connected to the brushless control unit 34. Diode D11, resistors R11, R12, and R13, capacitors C11, C12, and C13 are auxiliary circuit components of the peripheral connection circuit of the signal amplifier U1.

[0039] Wherein, the first end of the sampling resistor Rs is connected to the first input terminal J1, the second end of the sampling resistor Rs is connected to the second input terminal J2, the non-inverting input terminal of the signal amplifier U1 is connected to the first end of the sampling resistor Rs, the inverting input terminal of the signal amplifier U1 is connected to the second end of the sampling resistor Rs, the output terminal of the signal amplifier U1 is connected to the first output terminal J3, and the second end of the sampling resistor Rs is also connected to the second output terminal J4.

[0040] The operating voltage pin VS of the signal amplifier U1 is connected to the first input terminal J1 and the second input terminal J2 through a power conversion circuit (not shown in the figure). When the first input terminal J1 or the second input terminal J2 has a power supply voltage input, the pin VS has an operating voltage VDD input, and the signal amplifier U1 is powered on and enters the working state. When neither the first input terminal J1 nor the second input terminal J2 has a power supply voltage input, the signal amplifier U1 is powered off and stops working.

[0041] Referring to Figure 2, the gear position recognition unit 33 shown in Figure 5 operates as follows: 1-1) When both the first relay 12 and the second relay 13 are disconnected, corresponding to the stop position, there is no voltage input to the first input terminal J1 and the second input terminal J2. The signal amplifier U1 is powered off and stops working. Correspondingly, the brushless control unit 34 is also powered off and stops working, and the entire brushless fan assembly 3 is in a stopped state. In this case, the gear position recognition unit 33 responds to the lack of gear control signal input and does not output a gear position recognition signal. The brushless control unit 34 does not work due to the lack of power supply, and the brushless fan unit 31 stops operating.

[0042] 1-2) When the first relay 12 is engaged and the second relay 13 is disengaged, corresponding to the low-speed setting, the first input terminal J1 receives the power supply voltage, which is connected to the brushless control unit 34 via the sampling resistor Rs and the second output terminal J4. The second input terminal J2 receives no voltage input. Simultaneously, the signal amplifier U1 and the brushless control unit 34 obtain operating voltage from the first input terminal J1 and are both powered on. A voltage difference is generated across the sampling resistor Rs, with the potential at the first end of Rs being greater than that at the second end. After detecting this voltage difference, the signal amplifier U1 outputs an amplified voltage signal proportional to the current at the first output terminal J3, corresponding to the low-speed setting identification signal. The brushless control unit 34 then controls the brushless fan unit 31 to operate at low speed.

[0043] 1-3) When the first relay 12 is open and the second relay 13 is closed, corresponding to the high-speed mode, there is no voltage input at the first input terminal J1, and the second input terminal J2 receives the power supply voltage and is directly connected to the brushless control unit 34 through the second output terminal J4. Simultaneously, the signal amplifier U1 and the brushless control unit 34 obtain operating voltage from the second input terminal J2 and are both in a powered-on state. At this time, no current flows through the sampling resistor Rs, the voltage difference between its two ends is zero, and the first output terminal J3 of the signal amplifier U1 outputs zero voltage, corresponding to the high-speed mode identification signal. The brushless control unit 34 then controls the brushless fan unit 31 to operate at high speed.

[0044] In another preferred embodiment, as shown in Figures 4 and 6, the signal acquisition module 331 and the signal processing module 332 are integrated into the Hall effect current sensor chip U2 in the gear position recognition unit 33. The Hall effect current sensor chip U2 is connected to the power supply circuit of the compatible interface unit 32 and is used to detect the current flowing through its internal conductive path, and output a corresponding voltage signal as the gear position recognition signal based on the current. The Hall effect current sensor chip U2 can be an ACS712 series chip (such as ACS712ELCTR-20A). This chip integrates a low-impedance current sampling path (typically 1.2mΩ) and a linear Hall circuit. When the measured current flows through the copper conductive path inside the chip, a magnetic field proportional to the current is generated. The Hall circuit converts this magnetic field into a voltage signal proportional to the current and outputs it.

[0045] Specifically, as shown in Figure 6, consistent with the circuit shown in Figure 5, the first input terminal J1 represents the voltage input terminal connected to the first positive power line 15 in the compatible interface unit 32, the second input terminal J2 represents the voltage input terminal connected to the second positive power line 16 in the compatible interface unit 32, the first output terminal J3 represents the gear position recognition signal output terminal connected to the brushless control unit 34, and the second output terminal J4 represents the DC voltage output terminal connected to the brushless control unit 34. Diode D21, resistor R21, resistor R22, capacitor C21, capacitor C22, and capacitor C23 are auxiliary circuit components of the peripheral connection circuit of chip U2.

[0046] The Hall effect current sensor chip U2 includes input pins IP+ and IP- and an output pin VOUT. Input pin IP+ is connected to the first input terminal J1, input pin IP- is connected to the second input terminal J2 and the second output terminal J4, and output pin VOUT is connected to the first output terminal J3.

[0047] Similar to the circuit shown in Figure 5, the operating voltage pin VCC of the Hall effect current sensor chip U2 is connected to the first input terminal J1 and the second input terminal J2 through a power conversion circuit (not shown in the figure). When the first input terminal J1 or the second input terminal J2 has a power supply voltage input, the pin VCC has an operating voltage VDD input, and the Hall effect current sensor chip U2 is powered on and enters the working state. When neither the first input terminal J1 nor the second input terminal J2 has a power supply voltage input, the Hall effect current sensor chip U2 is powered off and stops working.

[0048] The output characteristics of the Hall effect current sensor chip U2 are as follows: when the measured current is zero, the output pin VOUT outputs a reference voltage (typically VCC / 2, i.e., 2.5V); when the measured current is in the positive direction (flowing from IP+ to IP-), the output voltage increases linearly with the increase of current.

[0049] Referring to Figure 2, the gear position recognition unit 33 shown in Figure 6 operates as follows: 2-1) When both the first relay 12 and the second relay 13 are disconnected, corresponding to the stop position, there is no voltage input to the first input terminal J1 and the second input terminal J2. The Hall effect current sensor chip U2 is powered off and stops working. Correspondingly, the brushless control unit 34 is also powered off and stops working, and the entire brushless fan assembly 3 is in a stop state. In this case, the gear position recognition unit 33 responds to the lack of gear control signal input and does not output a gear position recognition signal. The brushless control unit 34 does not work due to lack of power supply, and the brushless fan unit 31 stops operating.

[0050] 2-2) When the first relay 12 is engaged and the second relay 13 is disengaged, corresponding to the low speed setting, the first input terminal J1 receives the power supply voltage from the input pin IP+ of chip U2, which is then connected to the brushless control unit 34 via the input pin IP- and the second output terminal J4. The second input terminal J2 receives no voltage input. Simultaneously, both chip U2 and the brushless control unit 34 receive their operating voltage from the first input terminal J1 and are in a powered-on state. Current flows through the internal conductive path of chip U2 (from pin IP+ to pin IP-), generating a magnetic field proportional to the current. After sensing by the Hall effect circuit, the first output terminal J3 outputs a voltage signal proportional to the current (greater than the reference voltage), corresponding to the low speed setting identification signal. The brushless control unit 34 then controls the brushless fan unit 31 to operate at low speed.

[0051] 2-3) When the first relay 12 is open and the second relay 13 is closed, corresponding to the high-speed mode, there is no voltage input at the first input terminal J1, and the second input terminal J2 receives the power supply voltage and is directly connected to the brushless control unit 34 through the second output terminal J4. Simultaneously, the chip U2 and the brushless control unit 34 obtain operating voltage from the second input terminal J2 and are both in a powered-on state. At this time, no current flows between the IP+ and IP- pins of the Hall effect current sensor chip U2, there is no current in the internal conductive path of the chip, the magnetic field is zero, and the Hall circuit outputs a reference voltage, i.e., the first output terminal J3 outputs a reference voltage, corresponding to the high-speed mode identification signal. The brushless control unit 34 then controls the brushless fan unit 31 to operate at high speed.

[0052] Besides the two preferred embodiments described above, the gear position recognition unit 33 can also be implemented in other ways. For example, a voltage divider resistor network can be used to detect the voltage value, or an optocoupler isolation detection circuit can be used to detect the on / off state. These embodiments can also achieve gear position signal recognition and all fall within the protection scope of this invention.

[0053] In some specific embodiments, as shown in FIG4, the brushless control unit 34 includes a microcontroller 341 and a brushless motor drive circuit 342. As shown in FIGS. 5 and 6, the gear position recognition unit 33 has a first output terminal J3 connected to the microcontroller 341, outputting a gear position recognition signal to the microcontroller 341. A second output terminal J4 is connected to the brushless motor drive circuit 342, providing a DC input voltage to the brushless motor drive circuit 342. The microcontroller 341 has an operating voltage pin, which is electrically connected to the compatible interface unit 32 via the power conversion circuit described above.

[0054] The microcontroller 341 (e.g., MCU) receives the gear position recognition signal output by the gear position recognition unit 33 and, according to a preset mapping relationship (e.g., the correspondence between the voltage value of the gear position recognition signal and the PWM duty cycle), outputs a PWM signal with the corresponding duty cycle to the brushless motor drive circuit 342. The brushless motor drive circuit 342 generates a corresponding drive signal based on the PWM signal and outputs it to the brushless fan unit 31 to drive the brushless fan unit 31 to operate.

[0055] In a preferred embodiment, the brushless motor drive circuit 342 is a three-phase full-bridge inverter circuit, including six power switches (such as MOSFETs or IGBTs) and their gate drive circuits. The six power switches form three half-bridges, with the midpoint of each half-bridge connected to one phase winding of the brushless fan unit 31. The gate drive circuit receives six PWM signals output from the microcontroller 341, performs level conversion and power amplification, and controls the on / off state of each power switch to achieve electronic commutation and speed control of the brushless motor. The gate drive circuit can employ a bootstrap circuit to drive the upper bridge arm power switches; this is existing technology and will not be elaborated further.

[0056] The preset mapping relationship in the microcontroller 341 can be configured according to actual application requirements. For example, for a two-speed control scheme, when the speed identification signal indicates the low speed, the microcontroller 341 identifies and outputs a PWM signal corresponding to the first duty cycle (e.g., 30%) of low-speed operation. The brushless motor drive circuit 342 drives the brushless fan unit 31 to operate at low speed according to the PWM signal. When the high speed is indicated, the microcontroller 341 identifies and outputs a PWM signal corresponding to the second duty cycle (e.g., 80% or 100%) of high-speed operation. The brushless motor drive circuit 342 drives the brushless fan unit 31 to operate at high speed according to the PWM signal.

[0057] In a preferred embodiment, the brushless fan assembly 3 is integrated into a separate housing, and the compatible interface unit 32 is disposed on the housing. The housing integrates and accommodates the brushless fan unit 31, the gear recognition unit 33, and the brushless control unit 34, forming an integrated assembly module. During installation, simply remove the original vehicle's brushed fan assembly 2, and directly plug the brushless fan assembly 3 provided in this embodiment into the original vehicle's wiring harness via the compatible interface unit 32. No additional wiring or modification is required, achieving a complete physical and electrical replacement of the brushed fan assembly.

[0058] The above specific implementation examples mainly use a typical two-speed control scheme as an example. In other optional embodiments, the speed control signal includes more speeds, such as a three-speed control scheme (stop, low speed, medium speed, high speed) or a four-speed control scheme. Accordingly, the speed identification unit 33 can detect and identify more electrical states and output corresponding speed identification signals; the preset mapping relationship in the microcontroller 341 includes more PWM duty cycles corresponding to speeds to achieve multi-speed control of the brushless fan unit 31.

[0059] In summary, the brushless fan assembly and the automotive cooling system including the brushless fan assembly provided by the embodiments of the present invention have the following beneficial effects: 1. Achieve non-destructive replacement: Through the cooperation of the compatible interface unit and the gear position recognition unit, the brushless fan assembly can directly replace the brushed fan assembly without changing the original vehicle cooling control unit and its control logic or modifying the original vehicle wiring harness. It is plug-and-play and meets the convenience requirements of automotive after-sales maintenance.

[0060] 2. The operating logic is consistent with the original vehicle and does not affect the overall vehicle performance: The start and stop of the fan and the speed switching completely follow the control logic of the original vehicle host. The water temperature control accuracy and air conditioning cooling effect are no less than the original brushed fan. In fact, due to the smoother speed regulation of the brushless motor, water temperature fluctuations can be reduced and the engine operation stability can be improved.

[0061] 3. Inheriting the core advantages of brushless motors, improving energy efficiency: Compared with the original brushed fan, the brushless motor has no carbon brush friction and no commutation sparks, which greatly reduces electromagnetic interference (EMI) and does not affect the normal operation of the vehicle's electronic equipment (instrument, sensor, audio); there is no inrush current when starting, avoiding pulling down the vehicle's voltage and protecting the original vehicle wiring harness, fuse and alternator; high efficiency at low speeds, no resistance energy consumption, reducing the load on the alternator; low operating noise, improving the driving comfort inside the vehicle.

[0062] 4. High versatility and wide compatibility: By adjusting the threshold parameters of the gear recognition circuit, it can be adapted to all models that use "multi-speed brushed cooling fans". There is no need to design separate solutions for different models, which reduces production and manufacturing costs and has great industrial promotion value.

[0063] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A brushless fan assembly adapted to a brush control method, characterized in that, This brushless fan assembly is used to replace the original brushed fan assembly in a car. The car's cooling control unit controls the different operating levels of the brushed fan assembly by outputting a gear control signal. The brushless fan assembly includes: a brushless fan unit; a compatible interface unit whose physical structure and electrical definition match the input interface unit of the brushed fan assembly, for connecting to the cooling control unit to receive the gear control signal; a gear identification unit whose input is connected to the compatible interface unit, for responding to the gear control signal and outputting a gear identification signal corresponding to the gear control signal; and a brushless control unit, connected to both the gear identification unit and the brushless fan unit, for responding to the gear identification signal and generating a corresponding drive signal to output to the brushless fan unit, thereby controlling the brushless fan unit to operate at a target operating level corresponding to the brushed fan assembly.

2. The brushless fan assembly according to claim 1, characterized in that, The gear control signal includes control signals with at least two different electrical states, each corresponding to a different operating gear of the original brushed fan assembly; the gear identification unit detects the electrical state of the gear control signal and outputs a corresponding gear identification signal.

3. The brushless fan assembly according to claim 2, characterized in that, The at least two different electrical states are at least two discrete voltage or current values.

4. The brushless fan assembly according to claim 2, characterized in that, The gear position recognition unit includes a signal acquisition module and a signal processing module; the signal acquisition module is connected to the power circuit of the compatible interface unit and is used to acquire a sampled signal that characterizes the electrical state of the gear position control signal; the signal processing module is connected to the signal acquisition module and is used to process the sampled signal and output the gear position recognition signal.

5. The brushless fan assembly according to claim 4, characterized in that, The signal acquisition module includes a sampling resistor, and the signal processing module includes a signal amplifier. The sampling resistor is connected to the power supply circuit of the compatible interface unit, and the input terminal of the signal amplifier is connected to both ends of the sampling resistor. The signal amplifier is used to amplify the voltage difference across the sampling resistor and output the amplified voltage signal as the gear identification signal.

6. The brushless fan assembly according to claim 4, characterized in that, The signal acquisition module and the signal processing module are integrated in the Hall effect current sensor chip; the Hall effect current sensor chip is connected to the power supply circuit of the compatible interface unit to detect the current flowing through its internal conductive path, and outputs a corresponding voltage signal as the gear position identification signal based on the current.

7. The brushless fan assembly according to claim 1, characterized in that, The gear control signal includes at least three control signals corresponding to three electrical states: stop, low speed, and high speed. The gear identification unit responds to the gear control signal and outputs a gear identification signal corresponding to the stop, low speed, or high speed. The brushless control unit responds to the gear identification signal and controls the brushless fan unit to be in a stopped, low speed, or high speed state, respectively.

8. The brushless fan assembly according to claim 1, characterized in that, The brushless fan assembly is integrated into a separate housing, and the compatible interface unit is disposed on the housing to achieve a complete physical and electrical replacement of the original brushed fan assembly of the vehicle.

9. The brushless fan assembly according to any one of claims 1-8, characterized in that, The brushless control unit includes a microcontroller and a brushless motor drive circuit; the microcontroller receives the gear identification signal from the gear identification unit and outputs a PWM signal with a corresponding duty cycle to the brushless motor drive circuit; the brushless motor drive circuit generates a corresponding drive signal based on the PWM signal and outputs it to the brushless fan unit to drive the brushless fan unit to run; the brushless motor drive circuit is a three-phase full-bridge inverter circuit.

10. An automotive cooling system, characterized in that, It includes a cooling control unit and a brushless fan assembly as described in any one of claims 1-9, wherein a compatible interface unit in the brushless fan assembly is electrically connected to the cooling control unit.

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