A performance test circuit, system and method for an automobile air conditioner fan speed regulation module

Abstract

The application discloses a performance test circuit, system and method of a speed regulating module of an automobile air conditioner fan, and the system comprises a power supply unit, a control unit, a user input unit, an information output unit, an information transmission unit and at least one test unit, the power supply unit is used for supplying power to the whole system, the control unit comprises a host computer, each test unit comprises a test board and a voltage acquisition device, the test board communicates with the host computer through the information transmission unit, the host computer is used for sending a test instruction to the test board, the test board is connected with a to-be-tested speed regulating module and is used for outputting a linear voltage to the to-be-tested speed regulating module, the voltage of both ends of a blower fan is controlled, the voltage acquisition device is connected in parallel with the blower fan and is used for acquiring the voltage of both ends of the blower fan and sending the voltage to the corresponding test board. The system has the characteristics of a large number of tested products at one time, high measurement accuracy, fast measurement speed and stable operation.

Description

Technical Field

[0001] This invention belongs to the field of speed control module testing, specifically relating to a performance testing circuit, system, and method for an automotive air conditioning fan speed control module. Background Technology

[0002] Currently, most performance tests of automotive air conditioning blower linear speed control modules use single test methods, which are slow in measurement efficiency. At the same time, the measurement accuracy is poor due to interference from the blower. There is currently no large-scale measurement solution suitable for the performance testing of automotive air conditioning blower linear speed control modules, which makes the testing cycle of this product long and the delivery speed slow. Summary of the Invention

[0003] The purpose of this invention is to overcome at least one defect in the prior art and to provide a performance testing circuit, system and method for an automotive air conditioning fan speed control module. This invention can at least solve the problems of slow measurement efficiency and poor measurement accuracy in traditional solutions, shorten the product testing cycle and improve the product delivery speed.

[0004] The technical solution of this invention is implemented as follows: This invention discloses a performance testing circuit for an automotive air conditioning fan speed control module, including a power supply circuit, a main control circuit, a blower voltage acquisition circuit, a PWM to linear voltage output circuit, a 485 communication circuit, a voltage output interface, and a feedback input interface. The power supply circuit is used to power the entire performance testing circuit. The blower voltage acquisition circuit is used to acquire the voltage at both ends of the blower and transmit it to the main control circuit. The first input terminal of the PWM to linear voltage output circuit is connected to the PWM output terminal of the main control circuit. The second input terminal of the PWM to linear voltage output circuit is connected to the feedback input interface. The output terminal of the PWM to linear voltage output circuit is connected to the voltage output interface. The main control circuit is connected to the 485 communication circuit for communication with a host computer via the 485 communication circuit.

[0005] Furthermore, the voltage acquisition circuit is used to receive the voltage at both ends of the blower sent by the voltage acquisition device, divide the voltage, acquire it, and transmit it to the AD sampling input terminal of the main control circuit.

[0006] Furthermore, the voltage acquisition circuit includes several resistors. One end of resistor R22 is connected to the first voltage input terminal M+, and the other end of resistor R22 is connected to one end of resistor R23, one end of capacitor C16 and one end of resistor R24 ​​respectively. The other ends of resistor R23 and capacitor C16 are grounded, and the other end of resistor R24 ​​is connected to the first AD sampling input terminal AD0 of the main control circuit.

[0007] One end of resistor R27 is connected to the second voltage input terminal M-, and the other end of resistor R27 is connected to one end of resistor R26, one end of capacitor C17 and one end of resistor R25 respectively. The other ends of resistor R26 and capacitor C17 are grounded, and the other end of resistor R25 is connected to the second AD sampling input terminal AD1 of the main control circuit.

[0008] The first voltage input terminal M+ is used to connect to one end of the voltage acquisition device, and the second voltage input terminal M- is used to connect to the other end of the voltage acquisition device. The two ends of the voltage acquisition device are connected in parallel to the two ends of the blower.

[0009] Furthermore, the PWM to linear voltage output circuit includes transistors Q1 and Q2, operational amplifier U4.1, and transistor Q3. The base of transistor Q1 is connected to the PWM output terminal of the main control circuit through resistor R3. The base of transistor Q1 is also connected to one end of resistor R4, and the other end of resistor R4 is grounded. The emitter of transistor Q1 is grounded. The collector of transistor Q1 is connected to the base of transistor Q2 through resistor R5. The base of transistor Q2 is also connected to a third voltage through resistor R6. The emitter of transistor Q2 is connected to a third voltage. The collector of transistor Q2 is connected to one end of resistor R7 and one end of resistor R8, respectively. The other end of resistor R7 is grounded. The other end of resistor R8 is connected to one end of resistor R9 and one end of resistor R10, respectively. The other end of resistor R9 is used to connect to... The feedback input interface is connected with a capacitor C12 in parallel across resistor R9. The other end of resistor R10 is connected to the non-inverting input of op-amp U4.1 and one end of capacitor C13. The other end of capacitor C13 is connected to the inverting input of op-amp U4.1. The inverting input of op-amp U4.1 is connected to one end of resistor R12, one end of resistor R11, and one end of capacitor C14. The other end of resistor R12 is grounded. The other end of resistor R11 is connected to a third voltage. The other end of capacitor C14 is connected to the output of op-amp U4.1. The output of op-amp U4.1 is connected to the base of transistor Q3 via resistor R13. The collector of transistor Q3 is connected to the third voltage. The emitter of transistor Q3 is connected to the voltage output interface. The emitter of transistor Q3 is grounded via capacitor C15.

[0010] The positive terminal of the power supply of op-amp U4.1 is connected to the third voltage, and the negative terminal of the power supply of op-amp U4.1 is grounded.

[0011] This invention discloses a performance testing system for an automotive air conditioning blower speed control module, comprising a power supply unit, a control unit, an information transmission unit, and at least one testing unit. The power supply unit supplies power to the entire system. The control unit includes a host computer. Each testing unit includes a test board and a voltage acquisition device. The test board communicates with the host computer via the information transmission unit. The host computer sends test commands to the test board. The test board is connected to the speed control module under test and outputs a linear voltage to the module to control the voltage across the blower. The voltage acquisition device is connected in parallel with the blower and collects the voltage across the blower and sends it to the corresponding test board.

[0012] Furthermore, the D terminal of the speed control module under test is connected to the negative pin of the blower, the positive pin of the blower is connected to the first voltage, and the S terminal of the speed control module under test is grounded. When the speed control module under test has a feedback signal pin, the feedback input interface of the test board is connected to the F terminal of the speed control module under test. When the speed control module under test does not have a feedback signal pin, the feedback input interface of the test board is connected to the D terminal of the speed control module under test.

[0013] Furthermore, the control unit also includes a controller, which communicates with the host computer via an information transmission unit. Each test unit also includes a first switch connected in series with the blower, a second switch for controlling the connection or disconnection between the feedback input interface of the test board and the F terminal of the speed control module under test, and a third switch for controlling the connection or disconnection between the feedback input interface of the test board and the D terminal of the speed control module under test. The first, second, and third switches are respectively connected to the controller. The controller is used to receive control commands from the host computer and output control signals to control the on / off state of the first, second, and third switches.

[0014] The D terminal of the speed control module under test is connected to the negative pin of the blower via the first switch, and the positive pin of the blower is connected to the first voltage.

[0015] Furthermore, the first switch is the normally open contact of the first relay, and the normally open contact of the first relay is connected in series between the D terminal of the speed control module under test and the negative pin of the blower. One end of the coil of the first relay is connected to the first output terminal of the controller, and the other end of the coil of the first relay is connected to the second voltage.

[0016] The second switch is a normally closed contact of the second relay, the third switch is a normally open contact of the second relay, one end of the coil of the second relay is connected to the second output terminal of the controller, and the other end of the coil of the second relay is connected to the second voltage.

[0017] Furthermore, the performance measurement and control system of the automotive air conditioning fan linear speed regulation module of the present invention also includes a user input unit and an information output unit. The user input unit includes a mouse and a keyboard, which are connected to a host computer. The user input unit also includes a start button and an emergency stop button, which are electrically connected to the controller.

[0018] The information output unit includes a display unit, which is connected to a host computer.

[0019] The information output unit also includes indicator lights for indicating whether the test is qualified. Each test unit corresponds to at least one indicator light. Each indicator light is electrically connected to the controller, which is used to receive control commands from the host computer and control the working status of the indicator lights.

[0020] The display unit is a monitor.

[0021] The information output unit also includes a sound alarm, which is electrically connected to the controller. The sound alarm can be a buzzer.

[0022] Furthermore, the performance measurement and control system for the linear speed regulation module of the automotive air conditioning fan of the present invention also includes at least one execution unit, each execution unit corresponding to a test unit. Each execution unit includes a positioning cylinder for connecting the speed regulation module under test to the circuit of the corresponding test unit. The positioning cylinder is electrically connected to a controller, which receives control commands from a host computer and controls the positioning cylinder to rise and fall. Each positioning cylinder is provided with an upper magnetic switch and a lower magnetic switch. The upper magnetic switch is used to detect whether the positioning cylinder has risen to the correct position and sends the information to the controller. The lower magnetic switch is used to detect whether the positioning cylinder has fallen to the correct position and sends the information to the controller.

[0023] Each execution unit also includes a marking cylinder for marking qualified products. The marking cylinder is electrically connected to the controller, which receives control commands from the host computer and controls the marking cylinder to rise and fall. Each marking cylinder is equipped with an upper magnetic switch and a lower magnetic switch. The upper magnetic switch is used to detect whether the marking cylinder has risen to the correct position and sends the information to the controller. The lower magnetic switch is used to detect whether the marking cylinder has fallen to the correct position and sends the information to the controller.

[0024] Furthermore, the power supply unit includes at least one first power supply module, one second power supply module, and at least one third power supply module. The number of first power supply modules is the same as the number of test units and corresponds one-to-one. They are used to provide a first voltage to the corresponding test units. The number of third power supply modules is the same as the number of test units and corresponds one-to-one. They are used to provide a third voltage to power the test board of the corresponding test unit. The second power supply module is used to output a second voltage.

[0025] The power supply unit also includes a switch S1, which is located between the AC power supply and the input terminals of the first power module, the second power module, and the third power module.

[0026] The power supply unit also includes a power adapter for supplying power to the host computer, and a switch S2 is provided between the power adapter and the AC power supply.

[0027] This invention discloses a performance testing method for an automotive air conditioning fan speed control module, comprising the following steps:

[0028] Start measurement;

[0029] Power on the speed control module under test;

[0030] The host computer sends measurement commands containing the upper and lower limits of each range to the test board in sequence through the information transmission module. After receiving the measurement commands sent by the host computer, the test board performs the corresponding test and feeds back the test results to the host computer through the information transmission module.

[0031] Each time the host computer sends a measurement command containing the upper and lower limits of a range to the test board, it checks the status of each test board in real time. If the adjustment is complete, it checks if the feedback flag is 1. If the feedback flag is not 1, it displays the current voltage value, sends a stop measurement command, and outputs a non-compliance message. If the feedback flag is 1, it displays the voltage value of the current range and checks if all ranges have been measured. If not, the host computer sends a measurement command containing the upper and lower limits of the next range to the test board through the information transmission module. If all ranges have been measured, it checks if all ranges are qualified. If all ranges are qualified, it sends a stop measurement command and outputs a qualification message. If not all ranges are qualified, it sends a stop measurement command and outputs a non-compliance message.

[0032] Furthermore, after receiving the measurement command from the host computer, the test board executes the corresponding test, specifically including:

[0033] The test board monitors the measurement commands sent by the host computer in real time, parses the measurement commands, and determines whether the command is to adjust the voltage at both ends of the blower to a certain voltage range.

[0034] If the instruction is to adjust the voltage across the blower to a certain voltage range, then set the flag indicating that the voltage across the blower has been adjusted to the corresponding range to 0, obtain the range value to be adjusted by parsing the instruction, collect the current voltage across the blower, and determine whether the current voltage value is greater than the upper limit of the range value to be adjusted. If not, then execute step S1); if yes, then set the timer and execute step S2.

[0035] If the instruction is not to adjust the voltage across the blower to a certain voltage range, then determine whether it is an instruction to query the current voltage adjustment completion. If not, proceed to step S3); if yes, continue to determine whether the flag indicating that the voltage across the blower has been adjusted to the corresponding range is 0. If it is 0, proceed to step S4); if it is not 0, proceed to step S5.

[0036] S1) Continue to determine whether the current voltage value is within the range to be adjusted. If yes, set the voltage adjustment to the corresponding range flag at both ends of the blower to 1, indicating that the adjustment has been completed. If no, set the timer time and execute step S11).

[0037] S11) Determine if the current duty cycle of PWM is 100%. If the current duty cycle of PWM is 100%, turn off the timer and set the blower voltage adjustment to the corresponding range flag to 2, indicating that the product is open-circuited and the blower voltage cannot be adjusted to the range to be adjusted. If the current duty cycle of PWM is not 100%, add the first set value to the current value of PWM to increase the voltage across the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, set the blower voltage adjustment to the corresponding range flag to 1, indicating that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timing time has been reached. If the timing time has not been reached, return to step S11). If the timing time has been reached, set the blower voltage adjustment to the corresponding range flag to 4, indicating that the adjustment has timed out.

[0038] S2) Determine if the current duty cycle of the PWM is 0%. If the current duty cycle of the PWM is 0%, turn off the timer and set the blower voltage adjustment to the corresponding range flag to 3, indicating that the product is short-circuited and the blower voltage cannot be adjusted to the range to be adjusted. If the current duty cycle of the PWM is not 0%, subtract the second set value from the current PWM value to reduce the voltage across the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, set the blower voltage adjustment to the corresponding range flag to 1, indicating that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timeout period has been reached. If the timeout period has not been reached, return to step S2). If the timeout period has been reached, set the blower voltage adjustment to the corresponding range flag to 4, indicating that the adjustment has timed out.

[0039] S3) Set the PWM duty cycle to 0% to turn off the blower;

[0040] S4) Measure the current blower voltage and reply to the host computer that the adjustment is not complete;

[0041] S5) Measure the voltage across the blower terminals and reply to the host computer with the current voltage value and corresponding flag.

[0042] The present invention has at least the following beneficial effects:

[0043] In the power supply section of each module of the present invention, the DC13.5V / 30A main power supply of each product is separate from the DC12V test power supply, and they only share a ground wire. This avoids the influence of the main power supply on the test power supply, improves the stability of the test board power supply, and makes the reference source of the AD sampling of the test board more accurate and the measurement more accurate.

[0044] The control system consists of two types of controls: PC control, which is responsible for the main control of the testing section, primarily sending test and control commands, receiving test data, and automatically determining the test results; and PLC control, which is mainly responsible for the execution and display of the execution and PC's result display. The PLC executes actions such as cylinder pressing down to align with the product, automatic marking of pass / fail indicators, and driving the buzzer and indicator lights based on the received PC control commands. The test board performs the test after receiving the PC's test commands. This complete independence between testing and control avoids mutual interference and improves measurement stability.

[0045] The buttons employ a dual-start operation to ensure operator safety. An emergency stop button is also added for further safety. The execution unit is responsible for collecting data from the operation buttons, the movement of the positioning and marking cylinders, and the arrival magnetic switch. The positioning cylinder is used for connecting the product to the circuitry, and the marking cylinder is used to mark qualified products. Each cylinder is equipped with an up / down arrival magnetic switch to detect whether the cylinder has reached its designated position, making the execution unit more reliable. The relay section can be freely selected depending on whether the product has built-in feedback, allowing for the measurement of a wider variety of products. Simultaneously, another set of relays controls the start and stop of the fan, preventing live plugging and unplugging and protecting the product from electrical shock.

[0046] The testing section receives the test information for each gear position from the PC, executes the measurement and control, and sends the test information for each gear position back to the PC. The testing section is independent; it performs autonomous testing after receiving control commands from the PC. This ensures real-time testing and makes the testing more accurate. The testing section only sends feedback on the completion status of the test to the control section, keeping the amount of data transmitted small and ensuring that data transmission does not consume testing time, thus guaranteeing real-time testing.

[0047] The information transmission section uses RS485 for data transmission, which makes the modules more independent and eliminates interference between them, making the entire system more reliable.

[0048] The user input and information output section consists of indicator lights, a buzzer, a monitor, a keyboard, and a mouse, allowing users to freely set relevant parameters. The indicator lights and buzzer output the test results in an audio-visual manner, while the monitor accurately displays the specific test results, making the system operation more convenient.

[0049] In summary, this system is characterized by its ability to test a large number of products at once, high measurement accuracy, fast measurement speed, and stable operation, making it more suitable for performance testing of batch 12V automotive air conditioning blower linear speed control modules. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a general block diagram of the performance measurement and control system for a four-station 12V automotive air conditioning blower linear speed control module provided in an embodiment of the present invention.

[0052] Figure 2 A circuit diagram of the power supply circuit of the test board provided in an embodiment of the present invention;

[0053] Figure 3 A circuit diagram of the main control circuit of the test board provided in an embodiment of the present invention;

[0054] Figure 4 A circuit diagram of the voltage acquisition circuit of the test board provided in an embodiment of the present invention;

[0055] Figure 5 A circuit diagram of the PWM to linear voltage output circuit of the test board provided in an embodiment of the present invention;

[0056] Figure 6 A circuit diagram of the 485 communication circuit of the test board provided in an embodiment of the present invention;

[0057] Figure 7 This is a flowchart of the upper part of the performance testing method for the automotive air conditioning fan speed control module provided in an embodiment of the present invention.

[0058] Figure 8The flowchart shows the second half of the performance testing method for the automotive air conditioning fan speed control module provided in this embodiment of the invention.

[0059] Figure 9 A flowchart illustrating the control process of the test board provided in this embodiment of the invention;

[0060] Figure 10 A flowchart of step S1 provided in an embodiment of the present invention;

[0061] Figure 11 A flowchart of step S2 provided in an embodiment of the present invention;

[0062] Figure 12 A flowchart of step S3 provided in an embodiment of the present invention;

[0063] Figure 13 A flowchart of step S4 provided in an embodiment of the present invention;

[0064] Figure 14 A flowchart of step S5 provided in an embodiment of the present invention. Detailed Implementation

[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only one embodiment of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" or "several" means two or more.

[0067] Example 1

[0068] See Figures 2 to 6This invention provides a performance testing circuit for an automotive air conditioning fan speed control module, including a power supply circuit, a main control circuit, a blower voltage acquisition circuit, a PWM to linear voltage output circuit, a 485 communication circuit, a voltage output interface for connecting to the G terminal of the speed control module under test, and a feedback input interface for connecting to the F or D terminal of the speed control module under test. The power supply circuit supplies power to the entire performance testing circuit. The blower voltage acquisition circuit acquires the voltage across the blower and transmits it to the main control circuit. The first input terminal of the PWM to linear voltage output circuit is connected to the PWM output terminal of the main control circuit. The second input terminal of the PWM to linear voltage output circuit is connected to the feedback input interface. The output terminal of the PWM to linear voltage output circuit is connected to the voltage output interface. The main control circuit is connected to the 485 communication circuit for communication with a host computer via the 485 communication circuit.

[0069] Furthermore, the voltage acquisition circuit is used to receive the voltage at both ends of the blower sent by the voltage acquisition device, divide the voltage, acquire it, and transmit it to the AD sampling input terminal of the main control circuit.

[0070] Furthermore, the power supply circuit includes a DC 12V to 5V converter circuit. This circuit uses a power module U1, and the converted 5V provides power support for the subsequent microcontroller control circuit and 485 communication circuit.

[0071] Furthermore, the power supply circuit includes a DC 12V to high-precision 5V converter circuit. This circuit uses power module U2, and the high-precision 5V output provides a high-precision reference source for subsequent AD sampling.

[0072] Furthermore, the performance test circuit for the automotive air conditioning fan speed control module also includes an external 12V DC power supply interface JP1, a control circuit interface JP2, and an RS485 communication circuit interface.

[0073] Furthermore, the main control circuit adopts a single-chip microcomputer minimum system, which is responsible for controlling PWM output, acquiring voltage at both ends of the blower, and receiving, executing, and feeding back 485 commands.

[0074] Furthermore, the voltage acquisition circuit includes several resistors. One end of resistor R22 is connected to the first voltage input terminal M+, and the other end of resistor R22 is connected to one end of resistor R23, one end of capacitor C16, and one end of resistor R24. The other ends of resistor R23 and capacitor C16 are grounded, and the other end of resistor R24 ​​is connected to the first AD sampling input terminal AD0 of the main control circuit. One end of resistor R27 is connected to the second voltage input terminal M-, and the other end of resistor R27 is connected to one end of resistor R26, one end of capacitor C17, and one end of resistor R25. The other ends of resistor R26 and capacitor C17 are grounded, and the other end of resistor R25 is connected to the second AD sampling input terminal AD1 of the main control circuit.

[0075] The blower's voltage acquisition circuit divides the voltage across the blower, acquires the voltage, and then converts it into corresponding voltage values ​​by the main control circuit. The main control circuit measures the voltages at M+ and M- respectively and calculates the voltage difference across the blower.

[0076] The first voltage input terminal M+ is used to connect to one end of the voltage acquisition device, and the second voltage input terminal M- is used to connect to the other end of the voltage acquisition device. The two ends of the voltage acquisition device are connected in parallel to the two ends of the blower.

[0077] Furthermore, the PWM to linear voltage output circuit includes transistors Q1 and Q2, operational amplifier U4.1, and transistor Q3. The base of transistor Q1 is connected to the PWM output terminal of the main control circuit through resistor R3. The base of transistor Q1 is also connected to one end of resistor R4, and the other end of resistor R4 is grounded. The emitter of transistor Q1 is grounded. The collector of transistor Q1 is connected to the base of transistor Q2 through resistor R5. The base of transistor Q2 is also connected to a third voltage through resistor R6. The emitter of transistor Q2 is connected to a third voltage. The collector of transistor Q2 is connected to one end of resistor R7 and one end of resistor R8, respectively. The other end of resistor R7 is grounded. The other end of resistor R8 is connected to one end of resistor R9 and one end of resistor R10, respectively. The other end of resistor R9 is used to connect to... The feedback input interface is connected with a capacitor C12 connected in parallel across resistor R9. The other end of resistor R10 is connected to the non-inverting input of operational amplifier U4.1 and one end of capacitor C13. The other end of capacitor C13 is connected to the inverting input of operational amplifier U4.1. The inverting input of operational amplifier U4.1 is connected to one end of resistor R12, one end of resistor R11, and one end of capacitor C14. The other end of resistor R12 is grounded. The other end of resistor R11 is connected to a third voltage. The other end of capacitor C14 is connected to the output of operational amplifier U4.1. The output of operational amplifier U4.1 is connected to the base of transistor Q3 via resistor R13. The collector of transistor Q3 is connected to the third voltage. The emitter of transistor Q3 is connected to the voltage output interface. The emitter of transistor Q3 is grounded via capacitor C15. The linear voltage output from the PWM to linear voltage output circuit controls the input voltage of the product, thereby controlling the voltage across the blower.

[0078] The positive terminal of the power supply of op-amp U4.1 is connected to the third voltage, and the negative terminal of the power supply of op-amp U4.1 is grounded.

[0079] The RS485 communication circuit in this embodiment can use the MAX485 chip. The RS485 communication circuit is used to transmit commands from the PC to the microcontroller and to transmit feedback results from the microcontroller back to the PC. Data transmission in this invention is performed via 485 twisted-pair shielded cable, ensuring stable transmission and significantly improving anti-interference capabilities.

[0080] Because the system is adjusted on a single measuring board, there are no large numbers of complex wiring connections. If the sampling is not concentrated on a single test board, the wires would be intricate and prone to generating interference signals.

[0081] The AD reference source for acquiring the output voltage at both ends of the blower in this invention is high-precision, which can ensure the stability of the reference source and thus ensure the accuracy of the AD sampling measurement results. In addition, the AD has a large number of bits (10 bits) and high resolution.

[0082] Simultaneously, the output voltage at both ends of the blower is acquired using a differential method, which can suppress common-mode signals.

[0083] Example 2

[0084] See Figures 1 to 6 This invention also discloses a performance testing system for an automotive air conditioning blower speed control module, comprising a power supply unit, a control unit, an information transmission unit, a user input unit, an information output unit, and at least one testing unit. The power supply unit supplies power to the entire system. The control unit includes a host computer, such as a PC. Each testing unit includes a test board and a voltage acquisition device. The test board is equipped with the circuit described in Embodiment 1. The test board communicates with the host computer via the information transmission unit. The host computer sends test commands to the test board. The voltage output interface of the test board is connected to the G terminal of the speed control module under test, and is used to output a linear voltage to the speed control module under test to control the voltage across the blower. The voltage acquisition device is connected in parallel with the blower and is used to acquire the voltage across the blower and send it to the corresponding test board.

[0085] Preferably, the system in this embodiment includes multiple test units. For example, the system in this embodiment includes four test units.

[0086] Furthermore, the D terminal of the speed control module under test is connected to the negative pin of the blower, the positive pin of the blower is connected to the first voltage, and the S terminal of the speed control module under test is grounded. When the speed control module under test has a feedback signal pin, the feedback input interface of the test board is connected to the F terminal of the speed control module under test. When the speed control module under test does not have a feedback signal pin, the feedback input interface of the test board is connected to the D terminal of the speed control module under test.

[0087] The G terminal of the speed control module under test is the input terminal of the speed control module under test, the F terminal of the speed control module under test is the feedback terminal of the speed control module under test, the D terminal of the speed control module under test is the output terminal of the speed control module under test, and the S terminal of the speed control module under test is the ground terminal of the speed control module under test.

[0088] Furthermore, the control unit also includes a controller, which communicates with the host computer via an information transmission unit. Each test unit also includes a first switch connected in series with the blower, a second switch for controlling the connection or disconnection between the feedback input interface of the test board and the F terminal of the speed control module under test, and a third switch for controlling the connection or disconnection between the feedback input interface of the test board and the D terminal of the speed control module under test. The first, second, and third switches are respectively connected to the controller. The controller is used to receive control commands from the host computer and output control signals to control the on / off state of the first, second, and third switches.

[0089] The D terminal of the speed control module under test is connected to the negative pin of the blower via the first switch, and the positive pin of the blower is connected to the first voltage.

[0090] Furthermore, the first switch is the normally open contact of the first relay, and the normally open contact of the first relay is connected in series between the D terminal of the speed control module under test and the negative pin of the blower. One end of the coil of the first relay is connected to the first output terminal of the controller, and the other end of the coil of the first relay is connected to the second voltage.

[0091] The second and third switches can be separate switches or they can share a single switch. For example, the second switch is the normally closed contact of the second relay, and the third switch is the normally open contact of the second relay. One end of the coil of the second relay is connected to the second output terminal of the controller, and the other end of the coil of the second relay is connected to the second voltage.

[0092] The user input unit includes a mouse and a keyboard, which are connected to a host computer.

[0093] Furthermore, the information output unit includes a display unit, which is connected to the host computer.

[0094] Users can input their judgment criteria using a mouse and keyboard, and the test results will be displayed and indicated. At the same time, the test results will be prompted through audible and visual alarms.

[0095] Furthermore, the user input unit also includes a start button and an emergency stop button, which are electrically connected to the controller.

[0096] Furthermore, the information output unit also includes indicator lights for indicating whether the test is qualified or not. Each test unit corresponds to at least one indicator light, and each indicator light is electrically connected to a controller. The controller is used to receive control commands from the host computer and control the working status of the indicator lights. In this embodiment, each test unit corresponds to two indicator lights, one for indicating qualified and one for indicating unqualified.

[0097] Furthermore, the display unit is a monitor.

[0098] Furthermore, the information output unit also includes a sound alarm, which is electrically connected to the controller. The sound alarm can be a buzzer.

[0099] Furthermore, the performance measurement and control system for the linear speed regulation module of the automotive air conditioning fan of the present invention also includes at least one execution unit, each execution unit corresponding to a test unit. Each execution unit includes a positioning cylinder for connecting the speed regulation module under test to the circuit of the corresponding test unit. The positioning cylinder is electrically connected to a controller, which receives control commands from a host computer and controls the positioning cylinder to rise and fall. Each positioning cylinder is provided with an upper magnetic switch and a lower magnetic switch. The upper magnetic switch is used to detect whether the positioning cylinder has risen to the correct position and sends the information to the controller. The lower magnetic switch is used to detect whether the positioning cylinder has fallen to the correct position and sends the information to the controller.

[0100] Furthermore, each execution unit also includes a marking cylinder for marking qualified products. The marking cylinder is electrically connected to the controller, which receives control commands from the host computer and controls the marking cylinder to rise and fall. Each marking cylinder is equipped with an upper magnetic switch and a lower magnetic switch. The upper magnetic switch is used to detect whether the marking cylinder has risen to the correct position and sends the information to the controller. The lower magnetic switch is used to detect whether the marking cylinder has fallen to the correct position and sends the information to the controller.

[0101] Furthermore, the power supply unit includes at least one first power supply module, one second power supply module, and at least one third power supply module. The number of first power supply modules is the same as the number of test units and corresponds one-to-one. They are used to provide a first voltage to the corresponding test units. The number of third power supply modules is the same as the number of test units and corresponds one-to-one. They are used to provide a third voltage to power the test board of the corresponding test unit. The second power supply module is used to output a second voltage.

[0102] Furthermore, the power supply unit also includes a switch S1, which is located between the AC power supply and the input terminals of the first power supply module, the second power supply module, and the third power supply module.

[0103] Furthermore, the power supply unit also includes a power adapter for supplying power to the host computer, and a switch S2 is provided between the power adapter and the AC power supply.

[0104] Each module's power supply section consists of power supplies with different voltages. Among them, S2 controls the PC's power adapter separately, independent of the switches of other power supplies. This way, when shutting down the system, the PC will not be directly powered off and shut down.

[0105] Furthermore, the first power module is used to convert AC to a first voltage output, the second power module is used to convert AC to a second voltage output, and the third power module is used to convert AC to a third voltage output. The first power module is an adjustable switching power supply. The second power module is a D24V switching power supply. The third power module is a D12V switching power supply.

[0106] In the power supply section of each module, the DC13.5V / 30A main power supply of each product is separate from the DC12V test power supply, sharing only a ground wire. This avoids the influence of the main power supply on the test power supply, improves the stability of the test board's power supply, and makes the reference source of the AD sampling of the test board more accurate and the measurement more precise.

[0107] Each module's power supply section converts the 220V AC power into the DC voltage required by each module. The PLC in the control section uses a 24V DC power supply, so its power supply section converts 220V AC to 24V DC, with an output power of 24V / 10A. The execution section uses 13.5V for product measurement and control, and the maximum operating current of a single product reaches 20A during operation; therefore, a 220V AC to 13.5V / 30A adjustable switching power supply is used. The test board in the testing section is only used for measurement and control and does not participate in actual power output; therefore, a 220V AC to 12V / 2A DC power supply is used. The PC in the control section is powered by a power adapter, requiring 9V DC / 3A; therefore, a 220V AC to 9V DC / 3A power adapter is used to power it.

[0108] The control system consists of two types of controls: PC control, which is responsible for the main control of the testing section, primarily sending test and control commands, receiving test data, and automatically determining the test results; and PLC control, which is mainly responsible for the execution and display of the execution and PC's result display. The PLC executes actions such as cylinder pressing down to align with the product, automatic marking of pass / fail indicators, and driving the buzzer and indicator lights based on the received PC control commands. The test board performs the test after receiving the PC's test commands. This complete independence between testing and control avoids mutual interference and improves measurement stability.

[0109] The buttons employ a dual-start operation to ensure operator safety. An emergency stop button is also added for further safety. The execution unit is responsible for collecting data from the operation buttons, the movement of the positioning and marking cylinders, and the arrival magnetic switch. The positioning cylinder is used for connecting the product to the circuitry, and the marking cylinder is used to mark qualified products. Each cylinder is equipped with an up / down arrival magnetic switch to detect whether the cylinder has reached its designated position, making the execution unit more reliable. The relay section can be freely selected depending on whether the product has built-in feedback, allowing for the measurement of a wider variety of products. Simultaneously, another set of relays controls the start and stop of the fan, preventing live plugging and unplugging and protecting the product from electrical shock.

[0110] The testing section receives the test information for each gear position from the PC, executes the measurement and control, and sends the test information for each gear position back to the PC. The testing section is independent; it performs autonomous testing after receiving control commands from the PC. This ensures real-time testing and makes the testing more accurate. The testing section only sends feedback on the completion status of the test to the control section, keeping the amount of data transmitted small and ensuring that data transmission does not consume testing time, thus guaranteeing real-time testing.

[0111] The information transmission section transmits information between modules via an RS485 bus, employing differential half-duplex data transmission, which offers long transmission distances and high stability. It also provides electrical isolation between modules, ensuring complete independence for each module.

[0112] The user input and information output section consists of indicator lights, a buzzer, a monitor, a keyboard, and a mouse, allowing users to freely set relevant parameters. The indicator lights and buzzer output the test results in an audio-visual manner, while the monitor accurately displays the specific test results, making the system operation more convenient.

[0113] Example 3

[0114] See Figures 7 to 14 This invention provides a performance testing method for an automotive air conditioning fan speed control module, comprising the following steps:

[0115] Depending on whether the product has a feedback pin as configured by the user, the second or third switch of the test unit is turned on accordingly (i.e., the second relay of the test unit is energized or de-energized accordingly). When the speed control module under test has a feedback signal pin, the feedback input interface of the test board is connected to the F terminal of the speed control module under test. When the speed control module under test does not have a feedback signal pin, the feedback input interface of the test board is connected to the D terminal of the speed control module under test, i.e., the negative pin of the blower.

[0116] The start measurement specifically includes: monitoring the user's start signal, determining whether the start button (such as start button 1 and start button 2 in this embodiment) is pressed, turning off the buzzer when the start button is pressed, determining whether the emergency stop button is pressed, turning on the buzzer if the emergency stop button is pressed, and preparing to power on the speed control module under test if the emergency stop button is not pressed.

[0117] Powering on the speed control module under test specifically includes: opening the corresponding test channel, that is, controlling the first switch of the test unit to be turned on (such as energizing the first relay), controlling the positioning cylinder corresponding to the test unit to press down, and connecting the speed control module under test to the system through plug-in connection;

[0118] Turn off the indicator light that indicates whether the test is passed or failed;

[0119] The host computer obtains the upper and lower limit ranges set by the user (e.g., five upper and lower limit ranges are set in this embodiment), and sends measurement instructions containing the upper and lower limit ranges of each range to the test board of the test unit in sequence through the information transmission module. After receiving the measurement instructions sent by the host computer, the test board executes the corresponding test and feeds back the test results to the host computer through the information transmission module.

[0120] Each time the host computer sends a measurement command containing the upper and lower limits of a range to the test board, it checks the status of each test board in real time. If the adjustment is complete, it checks if the feedback flag is 1. If the feedback flag is not 1, it displays the current voltage value, sends a stop measurement command, and outputs a non-compliance message. If the feedback flag is 1, it displays the voltage value of the current range and checks if all ranges have been measured. If not, the host computer sends a measurement command containing the upper and lower limits of the next range to the test board through the information transmission module. If all ranges have been measured, it checks if all ranges are qualified. If all ranges are qualified, it sends a stop measurement command and outputs a qualification message. If not all ranges are qualified, it sends a stop measurement command and outputs a non-compliance message.

[0121] Closing the test channel means turning off the first switch of the test unit (e.g., de-energizing the first relay), which in turn controls the corresponding positioning cylinder to lift up.

[0122] If all gears pass, a stop measurement command is sent and a pass information is output, specifically including: controlling the dotting cylinder to mark the pass and the pass indicator light illuminating.

[0123] After receiving the measurement command from the host computer, the test board executes the corresponding test, which includes:

[0124] The test board monitors the measurement commands sent by the host computer in real time, parses the measurement commands, and determines whether the command is to adjust the voltage at both ends of the blower to a certain voltage range.

[0125] If the instruction is to adjust the voltage across the blower to a certain voltage range, then set the flag indicating that the voltage across the blower has been adjusted to the corresponding range to 0, obtain the range value to be adjusted by parsing the instruction, collect the current voltage across the blower, and determine whether the current voltage value is greater than the upper limit of the range value to be adjusted. If not, then execute step S1); if yes, then set the timer and execute step S2.

[0126] If the instruction is not to adjust the voltage across the blower to a certain voltage range, then determine whether it is an instruction to query the current voltage adjustment completion. If not, proceed to step S3); if yes, continue to determine whether the flag indicating that the voltage across the blower has been adjusted to the corresponding range is 0. If it is 0, proceed to step S4); if it is not 0, proceed to step S5.

[0127] S1) Continue to determine whether the current voltage value is within the range to be adjusted. If yes, set the voltage adjustment to the corresponding range flag at both ends of the blower to 1, indicating that the adjustment has been completed. If no, set the timer time and execute step S11).

[0128] S11) Determine if the current duty cycle of PWM is 100%. If the current duty cycle of PWM is 100%, turn off the timer and set the blower voltage adjustment to the corresponding range flag to 2, indicating that the product is open-circuited and the blower voltage cannot be adjusted to the range to be adjusted. If the current duty cycle of PWM is not 100%, add the first set value to the current value of PWM (the first set value in this embodiment can be set as needed, such as 1) to increase the voltage at both ends of the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, set the blower voltage adjustment to the corresponding range flag to 1, indicating that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timing time has been reached. If the timing time has not been reached, return to step S11). If the timing time has been reached, set the blower voltage adjustment to the corresponding range flag to 4, indicating that the adjustment has timed out.

[0129] S2) Determine if the current duty cycle of PWM is 0%. If the current duty cycle of PWM is 0%, turn off the timer and set the blower voltage adjustment to the corresponding range flag to 3, indicating that the product is short-circuited and the blower voltage cannot be adjusted to the range to be adjusted. If the current duty cycle of PWM is not 0%, reduce the current value of PWM by the second set value (the second set value in this embodiment is set as needed, such as 1) to reduce the voltage at both ends of the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, set the blower voltage adjustment to the corresponding range flag to 1, indicating that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timing time has been reached. If the timing time has not been reached, return to step S2). If the timing time has been reached, set the blower voltage adjustment to the corresponding range flag to 4, indicating that the adjustment has timed out.

[0130] S3) Set the PWM duty cycle to 0% to turn off the blower;

[0131] S4) Measure the current blower voltage and reply to the host computer that the adjustment is not complete;

[0132] S5) Measure the voltage across the blower terminals and reply to the host computer with the current voltage value and corresponding flag.

[0133] Step S5) specifically includes: determining whether the current blower voltage adjustment to the corresponding range flag is 1. If it is 1, then measure the voltage across the blower, and restore the current voltage value and adjustment status flag 1 of the host computer. If it is not 1, then determine whether the current blower voltage adjustment to the corresponding range flag is 2. If it is 2, then measure the voltage across the blower, and restore the current voltage value and product open circuit flag 2 of the host computer. If it is not 2, then continue to determine whether the current blower voltage adjustment to the corresponding range flag is 3. If it is 3, then measure the voltage across the blower, and restore the current voltage value and product short circuit flag 3 of the host computer. If it is not 3, then measure the voltage across the blower, and restore the current voltage value and adjustment timeout flag 4 of the PC.

[0134] In one embodiment of the present invention, measurement is initiated via a dual-start button. The PLC in the control unit controls the positioning cylinder in the execution unit to power the product. The positioning cylinder's lower magnetic switch provides feedback on the cylinder's positioning status. After the positioning cylinder reaches its position, the PLC in the control unit transmits a signal to the PC in the control unit via the information transmission unit, informing the PC that preparations for testing are complete.

[0135] The PC in the control section sends measurement commands for each range to the testing section via the information transmission section. The testing section executes the corresponding tests and transmits the test results back to the PC in the control section via the information transmission section. The PC displays the measurement results on the monitors in the user input and information output sections and sends the result information to the PLC in the control section via the information transmission section. The PLC controls the pass / fail indicator lights in the user input and information output sections to indicate the result information.

[0136] Before the PC in the control section sends the test information, the relay in the execution section will power on the product and automatically set the relay to connect to the feedback pin or the negative pin of the blower, depending on whether the test product has a feedback signal pin, as sent by the PC in the control section.

[0137] After all tests are completed, the PC in the control unit transmits the final information to the PLC in the control unit via the information transmission section. The PLC in the control unit then controls the positioning cylinder in the execution unit to lift up, and the lifting position is determined by the magnetic switch on the positioning cylinder. Next, it drives the dotting cylinder in the execution unit to perform dotting. The positioning position of the dotting cylinder is also determined by the up and down magnetic switch of the dotting cylinder in the execution unit. Simultaneously, the PC in the control unit transmits the final information to the PLC in the control unit via the information transmission section. The PLC in the control unit then activates the pass / fail indicators and triggers an audible and visual alarm via a buzzer.

[0138] In summary, this invention provides a performance testing solution that is easy to operate, highly reliable, suitable for batch testing, and offers high measurement accuracy.

[0139] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A performance testing system for an automotive air conditioning fan speed control module, characterized in that: The system includes a power supply unit, a control unit, an information transmission unit, and at least one test unit. The power supply unit supplies power to the entire system. The control unit includes a host computer. Each test unit includes a test board and a voltage acquisition device. The test board communicates with the host computer via the information transmission unit. The host computer sends test commands to the test board. The test board is connected to the speed control module under test and outputs a linear voltage to the speed control module under test to control the voltage across the blower. The voltage acquisition device is connected in parallel with the blower and collects the voltage across the blower and sends it to the corresponding test board. The test board monitors the measurement commands sent by the host computer in real time and parses the commands to determine whether the command is to adjust the voltage across the blower to a certain voltage range. If the command is to adjust the voltage across the blower to a certain voltage range, the range value to be adjusted is obtained by parsing the command. The current voltage across the blower is collected, and it is determined whether the current voltage value is greater than the upper limit of the range value to be adjusted. If not, step S1 is executed. If so, the timer is set, and step S2 is executed. S1) Continue to determine whether the current voltage value is within the range to be adjusted. If yes, it indicates that the adjustment has been completed. If not, set the timer and execute step S11). S11) Determine if the current duty cycle of the PWM is 100%. If the current duty cycle of the PWM is 100%, it indicates that the product is open-circuited and cannot adjust the blower voltage to the range to be adjusted. Turn off the timer. If the current duty cycle of the PWM is not 100%, add the first set value to the current value of the PWM to increase the voltage across the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, it indicates that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timeout has been reached. If the timeout has not been reached, return to step S11). If the timeout has been reached, it indicates that the adjustment has timed out. S2) Determine if the current duty cycle of the PWM is 0%. If the current duty cycle of the PWM is 0%, it indicates that the product is short-circuited and cannot adjust the blower voltage to the range to be adjusted. Turn off the timer. If the current duty cycle of the PWM is not 0%, subtract the second set value from the current value of the PWM to reduce the voltage across the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, it indicates that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timeout has been reached. If the timeout has not been reached, return to step S2). If the timeout has been reached, it indicates that the adjustment has timed out.

2. The performance testing system for the automotive air conditioning fan speed control module as described in claim 1, characterized in that: The D terminal of the speed control module under test is connected to the negative pin of the blower, the positive pin of the blower is connected to the first voltage, and the S terminal of the speed control module under test is grounded. When the speed control module under test has a feedback signal pin, the feedback input interface of the test board is connected to the F terminal of the speed control module under test. When the speed control module under test does not have a feedback signal pin, the feedback input interface of the test board is connected to the D terminal of the speed control module under test. The control unit also includes a controller, which communicates with the host computer via an information transmission unit. Each test unit also includes a first switch connected in series with the blower, a second switch for controlling the connection or disconnection between the feedback input interface of the test board and the F terminal of the speed control module under test, and a third switch for controlling the connection or disconnection between the feedback input interface of the test board and the D terminal of the speed control module under test. The first, second, and third switches are respectively connected to the controller. The controller is used to receive control commands from the host computer and output control signals to control the on / off state of the first, second, and third switches.

3. The performance testing system for the automotive air conditioning fan speed control module as described in claim 1, characterized in that: It also includes a user input unit and an information output unit. The user input unit includes a mouse and a keyboard, which are connected to the host computer. The information output unit includes a display unit, which is connected to a host computer. The information output unit includes indicator lights for indicating whether the test is qualified or not. Each test unit corresponds to at least one indicator light. Each indicator light is electrically connected to the controller, which is used to receive control commands from the host computer and control the working status of the indicator lights.

4. The performance testing system for the automotive air conditioning fan speed control module as described in claim 1, characterized in that: It also includes at least one execution unit, which corresponds one-to-one with the test unit. Each execution unit includes a positioning cylinder for connecting the speed regulation module under test to the circuit of the corresponding test unit. The positioning cylinder is electrically connected to the controller, which is used to receive control commands from the host computer and control the positioning cylinder to rise and fall. Each positioning cylinder is provided with an upper magnetic switch and a lower magnetic switch. The upper magnetic switch is used to detect whether the positioning cylinder has risen to the correct position and send the rising position information to the controller. The lower magnetic switch is used to detect whether the positioning cylinder has fallen to the correct position and send the falling position information to the controller.

5. The performance testing system for the automotive air conditioning fan speed control module as described in claim 4, characterized in that: Each execution unit also includes a marking cylinder for marking qualified products. The marking cylinder is electrically connected to the controller, which receives control commands from the host computer and controls the marking cylinder to rise and fall. Each marking cylinder is equipped with an upper magnetic switch and a lower magnetic switch. The upper magnetic switch is used to detect whether the marking cylinder has risen to the correct position and sends the information to the controller. The lower magnetic switch is used to detect whether the marking cylinder has fallen to the correct position and sends the information to the controller.

6. The performance testing system for the automotive air conditioning fan speed control module as described in claim 1, characterized in that: The power supply unit includes at least one first power supply module, one second power supply module, and at least one third power supply module. The number of first power supply modules is the same as the number of test units and they correspond one-to-one. They are used to provide a first voltage to the corresponding test units. The number of third power supply modules is the same as the number of test units and they correspond one-to-one. They are used to provide a third voltage to power the test board of the corresponding test unit. The second power supply module is used to output a second voltage.

7. The performance testing system for the automotive air conditioning fan speed control module as described in claim 1, characterized in that: The test board includes a power supply circuit, a main control circuit, a blower voltage acquisition circuit, a PWM-to-linear voltage output circuit, a 485 communication circuit, a voltage output interface for connecting to the G terminal of the speed control module under test, and a feedback input interface for connecting to the F or D terminal of the speed control module under test. The power supply circuit supplies power to the entire performance test circuit. The blower voltage acquisition circuit acquires the voltage across the blower and transmits it to the main control circuit. The first input terminal of the PWM-to-linear voltage output circuit is connected to the PWM output terminal of the main control circuit. The second input terminal of the PWM-to-linear voltage output circuit is connected to the feedback input interface. The output terminal of the PWM-to-linear voltage output circuit is connected to the voltage output interface. The main control circuit is connected to the 485 communication circuit for communication with the host computer via the 485 communication circuit.

8. The performance testing system for the automotive air conditioning fan speed control module as described in claim 7, characterized in that: The PWM-to-linear voltage output circuit includes a first transistor, a second transistor, an operational amplifier, and a third transistor. The base of the first transistor is connected to the PWM output terminal of the main control circuit through a third resistor. The base of the first transistor is also connected to one end of a fourth resistor, the other end of which is grounded. The emitter of the first transistor is grounded. The collector of the first transistor is connected to the base of the second transistor through a fifth resistor. The base of the second transistor is also connected to a third voltage through a sixth resistor. The emitter of the second transistor is connected to a third voltage. The collector of the second transistor is connected to one end of a seventh resistor and one end of an eighth resistor, the other end of which is grounded. The other end of the eighth resistor is connected to one end of a ninth resistor and one end of a tenth resistor, the ninth... The other end of the resistor is used to connect to the feedback input interface. The first capacitor is connected in parallel across the two ends of the ninth resistor. The other end of the tenth resistor is connected to the non-inverting input of the operational amplifier and one end of the second capacitor. The other end of the second capacitor is connected to the inverting input of the operational amplifier. The inverting input of the operational amplifier is connected to one end of the twelfth resistor, one end of the eleventh resistor, and one end of the third capacitor. The other end of the twelfth resistor is grounded. The other end of the eleventh resistor is connected to the third voltage. The other end of the third capacitor is connected to the output of the operational amplifier. The output of the operational amplifier is connected to the base of the third transistor via the thirteenth resistor. The collector of the third transistor is connected to the third voltage. The emitter of the third transistor is connected to the voltage output interface. The emitter of the third transistor is grounded via the fourth capacitor.

9. A performance testing method for an automotive air conditioning fan speed control module, characterized in that: Includes the following steps: Start measurement; Power on the speed control module under test; The host computer sends measurement commands containing the upper and lower limits of each range to the test board in sequence through the information transmission module. After receiving the measurement commands sent by the host computer, the test board performs the corresponding test and feeds back the test results to the host computer through the information transmission module. Each time the host computer sends a measurement command containing the upper and lower limits of a range to the test board, it checks the status of each test board in real time. If the adjustment is complete, it checks whether the feedback flag is the adjustment complete flag. If the feedback flag is not the adjustment complete flag, it displays the current voltage value, sends a stop measurement command, and outputs a non-compliance message. If the feedback flag is the adjustment complete flag, it displays the voltage value of the current range and checks whether all ranges have been measured. If not all ranges have been measured, the host computer sends a measurement command containing the upper and lower limits of the next range to the test board through the information transmission module. If all ranges have been measured, it checks whether all ranges are qualified. If all ranges are qualified, it sends a stop measurement command and outputs a qualification message. If not all ranges are qualified, it sends a stop measurement command and outputs a non-compliance message. After receiving the measurement command from the host computer, the test board executes the corresponding test, which includes: The test board monitors the measurement commands sent by the host computer in real time, parses the measurement commands, and determines whether the command is to adjust the voltage at both ends of the blower to a certain voltage range. If the instruction is to adjust the voltage across the blower to a certain range, the range to be adjusted is obtained by parsing the instruction, the current voltage across the blower is collected, and it is determined whether the current voltage value is greater than the upper limit of the range to be adjusted. If not, step S1 is executed; if so, the timer is set, and step S2 is executed. S1) Continue to determine whether the current voltage value is within the range to be adjusted. If yes, it indicates that the adjustment has been completed. If not, set the timer and execute step S11). S11) Determine if the current duty cycle of the PWM is 100%. If the current duty cycle of the PWM is 100%, it indicates that the product is open-circuited and cannot adjust the blower voltage to the range to be adjusted. Turn off the timer. If the current duty cycle of the PWM is not 100%, add the first set value to the current value of the PWM to increase the voltage across the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, it indicates that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timeout has been reached. If the timeout has not been reached, return to step S11). If the timeout has been reached, it indicates that the adjustment has timed out. S2) Determine if the current duty cycle of the PWM is 0%. If the current duty cycle of the PWM is 0%, it indicates that the product is short-circuited and cannot adjust the blower voltage to the range to be adjusted. Turn off the timer. If the current duty cycle of the PWM is not 0%, subtract the second set value from the current value of the PWM to reduce the voltage across the blower. Determine if the current voltage value is within the range to be adjusted. If the current voltage value is within the range to be adjusted, it indicates that the adjustment has been completed. If the current voltage value is not within the range to be adjusted, determine if the timeout has been reached. If the timeout has not been reached, return to step S2). If the timeout has been reached, it indicates that the adjustment has timed out.

10. The method as described in claim 9, characterized in that: If the instruction is to adjust the voltage across the blower to a certain voltage range, then set the indicator that the voltage across the blower has been adjusted to the corresponding range to an incomplete adjustment indicator. When the adjustment is complete, set the indicator that the voltage across the blower terminals has been adjusted to the corresponding range as the adjustment completion indicator; When the product is open-circuited and the blower voltage cannot be adjusted to the range to be adjusted, the product is open-circuited when the voltage across the blower is adjusted to the corresponding range. When the adjustment timeout occurs, the indicator showing that the voltage across the blower terminals has been adjusted to the corresponding range will be used as the adjustment timeout indicator. When the product is short-circuited and the blower voltage cannot be adjusted to the range to be adjusted, the product short-circuit indicator is set when the voltage across the blower is adjusted to the corresponding range. If the instruction is not to adjust the voltage across the blower to a certain range, then determine if it is a query instruction to check if the current voltage adjustment is complete. If not, set the PWM duty cycle to 0% to turn off the blower. If it is, continue to determine if the indicator that the voltage across the blower has been adjusted to the corresponding range is an incomplete adjustment indicator. If it is an incomplete adjustment indicator, measure the current blower voltage and reply to the host computer that the adjustment is incomplete. If it is not an incomplete adjustment indicator, measure the voltage across the blower and reply to the host computer with the current voltage value and the corresponding indicator.

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