Fan control system, fan control method, and power electronic conversion device

Abstract

This application relates to the field of power electronics technology, and particularly to a fan control system, fan control method, and power electronic conversion device. The fan control system includes multiple fans, a controller, a signal conversion circuit, and a fan determination circuit. The controller outputs a first PWM signal based on temperature detection results; the signal conversion circuit, connected to the controller, converts the first PWM signal into an analog signal; the fan determination circuit, connected to the signal conversion circuit, determines the target fan among the multiple fans based on a preset voltage range corresponding to the analog signal, with different preset voltage ranges corresponding to different fans. Therefore, the target fan can be determined using the analog signal corresponding to the first PWM signal, enabling independent adjustment of multiple fans and reducing the occupation of controller PWM resources or interface resources during multi-fan control.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to fan control systems, fan control methods and power electronic conversion devices. Background Technology

[0002] A fan control system can be used to control the operating status of fans. For example, in an air-cooled power electronic converter, multiple fans are usually installed. The airflow generated by the operation of multiple fans can carry away the heat generated inside the device, thereby reducing the internal temperature of the device.

[0003] During the operation of power electronic converters, the temperatures of heat-generating components such as power devices, magnetic devices, and capacitors may change depending on the operating conditions. To keep the internal temperature of the device within an acceptable range, it is usually necessary to control the operation of the corresponding fans based on temperature detection results, such as controlling the fans to start, stop, or adjust their speed.

[0004] Existing fan control systems, when controlling multiple fans separately, typically require a controller to provide each fan with corresponding PWM control signals or other control signals, along with the configuration of corresponding signal interfaces and peripheral circuits. As the number of fans increases, the number of PWM output ports or other interface ports required by the controller also increases, leading to increased hardware resource consumption and circuit complexity in the fan control system. Therefore, reducing the resource consumption of the controller during multi-fan control is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a fan control system, a fan control method, and a power electronic conversion device to effectively reduce the occupation of controller PWM resources or interface resources during multi-fan control.

[0006] The objective of this application is achieved through the following technical solution: In a first aspect, embodiments of this application provide a fan control system, including: a plurality of fans; a controller configured to output a first PWM signal based on a temperature detection result; a signal conversion circuit connected to the controller, used to convert the first PWM signal into an analog signal; and a fan determination circuit connected to the signal conversion circuit, used to determine a target fan among the plurality of fans based on a preset voltage range corresponding to the analog signal; wherein different preset voltage ranges correspond to different fans.

[0007] In some embodiments, the controller is further configured to output an adjustment signal and an execution signal; the fan control system further includes a plurality of gear adjustment circuits, each corresponding to one of the plurality of fans; the fan determination circuit is used to convert the analog signal into an enable signal corresponding to the target fan; wherein, the gear adjustment circuit corresponding to the target fan is configured to: in response to the enable signal, determine the gear adjustment direction according to the adjustment signal, and perform gear adjustment of the target fan according to the gear adjustment direction based on the execution signal.

[0008] In some embodiments, the fan is configured with multiple speeds; the execution signal is further used to indicate the number of times the speed is adjusted; wherein, the speed adjustment circuit of the target fan is further configured to: based on the number of times the execution signal indicates, execute the speed adjustment according to the speed adjustment direction to adjust the speed by the number of times the adjustment is performed.

[0009] In some embodiments, the gear adjustment circuit includes a counter, which is used to determine a count value based on the execution signal; the fan control system further includes: multiple gear setting circuits and multiple gear conversion circuits, the multiple gear setting circuits corresponding one-to-one with the multiple fans, and the multiple gear conversion circuits corresponding one-to-one with the multiple fans; wherein, the gear setting circuit corresponding to the target fan is used to select a target voltage as a gear signal from multiple preset gear voltages based on the count value; the gear conversion circuit corresponding to the target fan is used to convert the gear signal into a second PWM signal to drive the corresponding fan.

[0010] In some embodiments, the plurality of fans are divided into at least two groups of fans; each group of fans is connected to the corresponding signal conversion circuit and the fan determination circuit; the controller is configured to output multiple first PWM signals, and different first PWM signals correspond to different fan groups.

[0011] In some embodiments, each fan group further includes multiple gear adjustment circuits, each corresponding to a fan in the fan group; the controller is further configured to output the adjustment signal and the execution signal to the gear adjustment circuit in each group; wherein the gear adjustment circuit enabled by the fan determination circuit of the corresponding fan group responds to the adjustment signal and the execution signal to perform gear adjustment.

[0012] In some embodiments, an analog-to-digital converter is further included, connected to the output of the signal conversion circuit, for converting the analog signal into a digital signal and sending it to the controller; the controller is further configured to adjust the first PWM signal according to the digital signal so that the analog signal is a target value; wherein the controller is configured to output the adjustment signal and the execution signal after determining that the analog signal is normal, or to output an alarm signal when determining that the analog signal is abnormal.

[0013] In some embodiments, each of the plurality of fans is provided with a speed feedback element, the speed feedback element being used to feed back the speed signal of each fan to the controller; the controller is further configured to determine whether the fan speed is normal based on the speed signal, and to output an abnormal signal when abnormal.

[0014] Secondly, embodiments of this application provide a fan control method, the method comprising: outputting a first PWM signal based on a temperature detection result; converting the first PWM signal into an analog signal; determining a target fan among a plurality of fans based on a preset voltage range corresponding to the analog signal; wherein different preset voltage ranges correspond to different fans.

[0015] Thirdly, embodiments of this application provide a power electronic conversion device, which includes a fan control system and a heat-generating component as described in any one of claims 1-8. The fan control system includes a plurality of fans and is used to determine a target fan among the plurality of fans based on the temperature detection result of the heat-generating component. The target fan is used to dissipate heat from the heat-generating component.

[0016] This application provides a fan control system, a fan control method, and a power electronic conversion device. This application addresses the problem that existing multi-fan control methods occupy a lot of controller PWM resources or interface resources. By converting the first PWM signal into an analog signal and determining the target fan among multiple fans according to the preset voltage range of the analog signal, the application effectively reduces the occupation of controller PWM resources or interface resources during multi-fan control. Attached Figure Description

[0017] This application will be further described below with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 This is a schematic diagram of a control circuit provided in an embodiment of this application.

[0019] Figure 2 This is a schematic diagram illustrating the relationship between the duty cycle of a speed control signal and the fan speed, provided in an embodiment of this application.

[0020] Figure 3 This is a schematic diagram of a fan control system provided in an embodiment of this application.

[0021] Figure 4 This is a schematic diagram of another fan control system provided in an embodiment of this application.

[0022] Figure 5 This is a schematic diagram of another fan control system provided in the embodiments of this application.

[0023] Figure 6 This is a schematic diagram of a fan control system provided in an embodiment of this application.

[0024] Figure 7 This is a schematic diagram of the specific circuit structure of a fan control system provided in an embodiment of this application.

[0025] Figure 8 This is a schematic diagram of the structure of a gear adjustment circuit and a gear setting circuit provided in an embodiment of this application.

[0026] Figure 9 This is a waveform diagram of a fan control system in operation provided in an embodiment of this application.

[0027] Figure 10 This is a schematic flowchart of a fan control method provided in an embodiment of this application.

[0028] Figure 11 This is a schematic diagram of the structure of a power electronic conversion device provided in an embodiment of this application.

[0029] Figure 12 This is a structural block diagram of a controller provided in an embodiment of this application. Detailed Implementation

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] In the description of the embodiments of this application, it should be understood that 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 indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0032] During the operation of a power electronic converter, its internal components, such as power devices, magnetic devices, and capacitors, generate heat; these components can be simply referred to as heat-generating components. To maintain the internal temperature of the power electronic converter within a suitable range and reduce its impact on operating efficiency, multiple fans can be installed within the power electronic converter to dissipate heat from the internal components, thereby lowering the internal temperature.

[0033] In some technical solutions, the power electronic converter can control the fan through its internal controller, which can adjust the fan operation based on temperature detection results. For example, when the temperature detection indicates that the temperature of a certain area or component is rising, the controller can increase the fan speed of the corresponding area or component; when the temperature detection indicates that the temperature of a certain area or component is decreasing, the controller can decrease the fan speed of the corresponding area or component. This allows the fan speed to be matched with the heat dissipation requirements, balancing heat dissipation effect and system efficiency.

[0034] For some specific implementations, please refer to Figure 1 The diagram illustrates a control circuit where the controller outputs a control signal PWM1. This signal, controlling the fan speed, is then transmitted via the control pin PV. The control circuit can be composed of diode D4, resistors R31, R33, R5, R6, R32, capacitor C9, and switching transistor Q5, as shown in the diagram. Specifically, the process of controlling the fan speed includes: the controller outputs the control signal PWM1, which is transmitted via diode D4, resistors R31, R33, and R6 to the control terminal of switching transistor Q5, causing Q5 to periodically turn on or off. When Q5 is off, the power supply terminal V5 provides a high level to the output node via resistor R5, resulting in a high-level signal at the control pin PV. When Q5 is on, the output node is connected to signal ground SGND via Q5, resulting in a low-level signal at the control pin PV. Thus, as Q5 periodically turns on and off, a speed control signal is generated at the control pin PV. Within a PWM cycle, the longer the duration of the high-level signal received by the control pin PV, the higher the fan speed; conversely, the longer the duration of the low-level signal received by the control pin PV, the lower the fan speed.

[0035] Figure 2 This diagram illustrates the relationship between the duty cycle of the speed control signal and the fan speed. The horizontal axis, DUTY, represents the duty cycle of the speed control signal, and the vertical axis, RPM, represents the fan speed. Figure 1It can be seen that as the duty cycle of the speed control signal increases, the fan speed increases accordingly; as the duty cycle of the speed control signal decreases, the fan speed decreases accordingly. In other words, the fan can adjust its own speed according to the duty cycle of the speed control signal received by the PWM control pin PV. Therefore, in fan control, if it is necessary to independently adjust the speed of a specific fan, the controller usually needs to provide a corresponding PWM control signal for that fan, and the corresponding control circuit for that fan converts the PWM control signal into a speed control signal.

[0036] However, when there are a large number of fans, if the controller controls multiple fans through independent PWM output ports, it will require a significant amount of the controller's PWM resources or interface resources. Furthermore, as the number of fans increases, the resources required for the corresponding control circuits may also increase, leading to increased circuit complexity and resource consumption.

[0037] To address the aforementioned problems, this application proposes a fan control system. This fan control system first converts the first PWM signal output by the controller into an analog signal, and then determines the corresponding target fan based on the preset voltage range of the analog signal. Since different preset voltage ranges correspond to different fans, the controller can adjust the first PWM signal to allow subsequent circuitry to determine the target fan to be controlled. Therefore, by utilizing the first PWM signal and its corresponding analog signal value range, the target fan is determined, thereby reducing the occupation of controller PWM resources or interface resources during multi-fan control while allowing independent adjustment of multiple fans, and lowering the circuit complexity of the fan control system.

[0038] See Figure 3 , Figure 3 This is a schematic diagram of a fan control system provided in an embodiment of this application, including: multiple fans, a controller, a signal conversion circuit, and a fan determination circuit. The controller is configured to output a first PWM signal based on temperature detection results; the signal conversion circuit is connected to the controller and is used to convert the first PWM signal into an analog signal; the fan determination circuit is connected to the signal conversion circuit and is used to determine a target fan among the multiple fans based on a preset voltage range corresponding to the analog signal. Different preset voltage ranges correspond to different fans.

[0039] In some embodiments, a fan control system can be applied to power electronic converters. For example, a fan control system can be applied to large air-cooled power electronic converters such as electric vehicle charging systems, medium-voltage direct-connected inverters, medium-voltage direct-connected energy storage systems, and medium-voltage direct-connected static var generators. In these applications, power electronic converters typically include heat-generating components such as power devices, magnetic devices, and capacitors. These heat-generating components generate heat during operation, and the fan control system can use multiple fans to dissipate this heat, thereby maintaining the internal temperature of the power electronic converter within a suitable range.

[0040] Multiple fans can be positioned in different locations to meet the heat dissipation requirements of the power electronic converter. For example, in a power electronic converter, some fans can be placed near heat-generating components to increase airflow around them; others can be placed in the air duct of the power electronic converter to exhaust internal hot air. Thus, multiple fans can either cool different heat-generating components individually or work together to cool the same heat-generating component.

[0041] The controller may include one or more hardware structures such as a processor, memory, a PWM output interface, a general-purpose input / output interface, or a communication interface. The processor may include, but is not limited to, a microcontroller unit (MCU), a digital signal processor (DSP), or a field-programmable gate array (FPGA). To determine which fan needs to be controlled, in some embodiments, the controller can acquire temperature detection results and identify the fan corresponding to the device with the higher temperature as the fan to be controlled, or identify the fan corresponding to the device with the lower temperature as the fan to be controlled. Specifically, the controller can collect the temperature of various components inside the power electronic converter through temperature sensors. For example, the obtained temperature detection results may include the temperature of power devices, the temperature of magnetic devices, the temperature of the air duct, etc.

[0042] Clearly, in this embodiment, the controller does not need to output a separate signal for each fan. Instead, it determines the fan to be controlled (i.e., the target fan) based on the temperature detection results and outputs a first PWM signal corresponding to that fan via a Pulse Width Modulation (PWM) module. This first PWM signal characterizes the determined target fan. The controller can adjust one or more signal parameters of the first PWM signal, such as its frequency, duty cycle, pulse width, or period, so that different first PWM signals correspond to different target fans. In other words, the controller can express which fan needs to be controlled by changing the signal parameters of the first PWM signal. This reduces the need for the controller to configure independent selection signal output ports for multiple fans.

[0043] Since the first PWM signal is itself a pulse signal, a signal conversion circuit can be added to the fan control system to facilitate the identification of information carried in the first PWM signal by subsequent circuits. The signal conversion circuit is connected to the controller and receives the first PWM signal output by the controller. The signal conversion circuit can output an analog signal with corresponding values ​​based on the signal parameters of the first PWM signal. The analog signal can be an analog voltage signal or an analog current signal. In some embodiments, the analog signal can be an analog voltage signal to facilitate interval judgment by subsequent circuits. Thus, different first PWM signals output by the controller can be converted into analog signals of different magnitudes, and subsequent circuits can determine the target fan by judging the magnitude of the analog signal.

[0044] For example, the signal conversion circuit may include a PWM-to-analog signal circuit, which outputs an analog signal with a corresponding voltage value based on the frequency of the first PWM signal. For instance, when the frequency of the first PWM signal is a first frequency, the signal conversion circuit outputs an analog signal within a first voltage range; when the frequency of the first PWM signal is a second frequency, the signal conversion circuit outputs an analog signal within a second voltage range. The first voltage range and the second voltage range can be used to correspond to different fans. In a specific example, the duty cycle of the first PWM signal can be maintained at 50%, and the controller can change the analog signal output by the signal conversion circuit by adjusting the frequency of the first PWM signal. For example, when the frequency of the first PWM signal is 1kHz, the analog signal output by the signal conversion circuit can be stabilized at approximately 1V; when the frequency of the first PWM signal is 1.2kHz, the analog signal output by the signal conversion circuit can be stabilized at approximately 1.25V; when the frequency of the first PWM signal is 1.4kHz, the analog signal output by the signal conversion circuit can be stabilized at approximately 1.49V. These different voltage values ​​can fall into different preset voltage ranges so that subsequent circuits can distinguish between different fans.

[0045] In other embodiments, the signal conversion circuit may also include a low-pass filter circuit, an integrator circuit, or a duty cycle-to-voltage conversion circuit. Accordingly, the signal conversion circuit can output an analog signal with a corresponding voltage value based on the duty cycle of the first PWM signal. For example, when the duty cycle of the first PWM signal is small, the signal conversion circuit outputs an analog signal with a lower voltage value; when the duty cycle of the first PWM signal is large, the signal conversion circuit outputs an analog signal with a higher voltage value. Thus, regardless of whether the first PWM signal carries information through frequency or duty cycle, the signal conversion circuit can convert this information into an analog signal that is easy for subsequent stages to recognize.

[0046] After the signal conversion circuit outputs an analog signal, the fan determination circuit can further determine the target fan based on the analog signal. Specifically, the fan determination circuit is connected to the signal conversion circuit and receives the analog signal output by the signal conversion circuit. The fan determination circuit can determine the target fan from multiple fans based on the preset voltage range corresponding to the analog signal. Different preset voltage ranges correspond to different fans. In other words, after the signal conversion circuit converts the first PWM signal into an analog signal, the fan determination circuit can then convert the voltage range of the analog signal into the corresponding fan selection result.

[0047] The preset voltage range can be a pre-set voltage range used to distinguish different fans. Multiple preset voltage ranges can each have different upper and lower limits, and these ranges can be non-overlapping, allowing the fan determination circuit to uniquely identify the target fan based on the voltage value of the analog signal. For example, a first preset voltage range can correspond to the first fan among multiple fans, a second preset voltage range to the second fan, and a third preset voltage range to the third fan. When the analog signal falls within the first preset voltage range, the fan determination circuit can identify the first fan as the target fan; when the analog signal falls within the second preset voltage range, it can identify the second fan; and when the analog signal falls within the third preset voltage range, it can identify the third fan.

[0048] For example, the first preset voltage range can be 0.9V to 1.1V, the second preset voltage range can be 1.1V to 1.3V, and the third preset voltage range can be 1.3V to 1.5V. Correspondingly, when the analog signal is approximately 1V, the first fan can be identified as the target fan; when the analog signal is approximately 1.25V, the second fan can be identified as the target fan; and when the analog signal is approximately 1.49V, the third fan can be identified as the target fan. Thus, a preset correspondence can be established between the first PWM signal output by the controller, the analog signal output by the signal conversion circuit, the preset voltage ranges, and the fans.

[0049] In some embodiments, to determine which preset voltage range the analog signal falls within, the fan determination circuit can compare the voltage value of the analog signal with multiple preset voltage thresholds and determine the corresponding preset voltage range based on the comparison results. Exemplarily, the fan determination circuit may include at least a voltage detection chip and logic gate circuits, wherein the voltage detection chip may also be a comparator. The voltage detection chip or comparator can be used to determine whether the analog signal is higher than the corresponding preset voltage threshold, or to determine whether the analog signal is lower than the corresponding preset voltage threshold, respectively. The logic gate circuit can determine whether the analog signal is located between two adjacent preset voltage thresholds based on the detection results corresponding to those two adjacent preset voltage thresholds. Therefore, the fan determination circuit can determine the corresponding target fan based on the voltage value of the analog signal, thereby reducing the risk of multiple fans being mistakenly selected.

[0050] For example, a fan determination circuit may include voltage detection chips for detecting preset voltage thresholds such as 0.9V, 1.1V, 1.3V, and 1.5V. The fan determination circuit can perform logical operations on the outputs of two adjacent voltage detection chips to determine whether the analog signal falls between two adjacent preset voltage thresholds. For instance, when the analog signal is higher than 0.9V and lower than 1.1V, the fan determination circuit can determine that the analog signal is within the preset voltage range of 0.9V to 1.1V; when the analog signal is higher than 1.1V and lower than 1.3V, the fan determination circuit can determine that the analog signal is within the preset voltage range of 1.1V to 1.3V. Thus, the target fan can be determined by identifying the voltage range of the analog signal.

[0051] In actual control, the controller first determines the fan to be controlled based on temperature detection results, and then generates a first PWM signal corresponding to that fan according to a preset correspondence. The signal conversion circuit converts the first PWM signal into an analog signal falling within a corresponding preset voltage range. The fan determination circuit can then determine the fan corresponding to the preset voltage range in which the analog signal is located as the target fan. For example, when the temperature of the first heating component rises, the controller can output a first PWM signal matching the fan corresponding to the first heating component, thus identifying that fan as the target fan; when the temperature of the second heating component rises, the controller can output a first PWM signal matching the fan corresponding to the second heating component, thus identifying another fan as the target fan. In this way, the controller can flexibly switch the target fan according to the temperature state of different heating components.

[0052] Therefore, this embodiment of the application can utilize the analog signal value range corresponding to the first PWM signal to carry information, and parse this information into a target fan through a fan determination circuit. Compared to the method of the controller selecting and controlling multiple fans through multiple PWM output ports or multiple interface ports, this embodiment of the application can reduce the occupation of the controller's PWM resources or interface resources during multi-fan control, reduce the circuit complexity of the fan control system, and improve the applicability of the fan control system in scenarios with a large number of fans.

[0053] In some embodiments, after the fan determination circuit determines the target fan, the fan control system can further adjust the speed range of the target fan. For example... Figure 4 As shown, the fan control system may include multiple speed adjustment circuits, each corresponding to a fan. Each speed adjustment circuit can be used to adjust the corresponding fan speed level.

[0054] In this embodiment, after the fan determination circuit determines the target fan based on the analog signal, it can output an enable signal corresponding to the target fan. This enable signal can be input to the gear adjustment circuit corresponding to the target fan, making the gear adjustment circuit corresponding to the target fan responsive. Accordingly, even if the gear adjustment circuit that has not received a valid enable signal receives the adjustment signal and execution signal output by the controller, it cannot perform gear adjustment, thereby maintaining the current gear of the corresponding fan.

[0055] The enable signal can be active high or active low. For example, when the analog signal is within the preset voltage range corresponding to the target fan, the fan determination circuit can output a low level to enable the enable signal, making the gear adjustment circuit corresponding to the target fan responsive. When the analog signal is not within the preset voltage range corresponding to other fans, the enable signals corresponding to other fans can be active high or active low. In some embodiments, when the enable signal corresponding to other fans is active low, the fan determination circuit outputs a low level to enable the enable signal; the fan determination circuit outputs a high level to disable the enable signal. Therefore, the active or inactive state of the enable signal is determined by the signal level output by the fan determination circuit, not by whether the fan determination circuit outputs a signal. This allows only the gear adjustment circuit corresponding to the target fan to respond to subsequent control signals among multiple gear adjustment circuits, reducing the risk of other fans being incorrectly adjusted.

[0056] After the gear adjustment circuit corresponding to the target fan is enabled, the controller can also output adjustment signals and execution signals through the General-Purpose Input / Output (GPIO) module to control the gear adjustment circuit to perform gear adjustment. The adjustment signal can be used to indicate the gear adjustment direction, which can include increasing the gear or decreasing the gear. For example, when the adjustment signal is in a first-level state, it can indicate that the gear adjustment direction is increasing the gear; when the adjustment signal is in a second-level state, it can indicate that the gear adjustment direction is decreasing the gear. The execution signal can be used to trigger the gear adjustment circuit to perform gear adjustment according to the gear adjustment direction indicated by the adjustment signal. The execution signal can be a pulse signal, a level transition signal, or a clock signal, or any signal capable of triggering gear adjustment.

[0057] For example, when the temperature detection result indicates that the temperature of a certain heat-generating component has increased, requiring an increase in the speed of the corresponding fan, the controller can first output a first PWM signal corresponding to that fan. After the signal conversion circuit converts the first PWM signal into an analog signal, the fan determination circuit can output an enable signal corresponding to that fan based on the preset voltage range corresponding to the analog signal, thus enabling the speed adjustment circuit corresponding to that fan to be in a responsive state. Subsequently, the controller can output an adjustment signal indicating the direction of increasing the speed and an execution signal, causing the speed adjustment circuit to perform speed adjustment in the direction of increasing the speed, thereby increasing the fan speed.

[0058] Accordingly, when the temperature detection result indicates that the temperature of a certain heat-generating component has decreased, and the speed of the corresponding fan needs to be reduced, the controller can use the first PWM signal, the signal conversion circuit, and the fan determination circuit to make the speed adjustment circuit corresponding to that fan responsive. Subsequently, the controller can output an adjustment signal indicating the direction of decreasing the speed and output an execution signal to make the speed adjustment circuit perform speed adjustment in the direction of decreasing the speed, thereby reducing the speed of the fan.

[0059] For example, when the analog signal is within the preset voltage range corresponding to the second fan, the fan determination circuit can output an enable signal for the second fan, making the gear adjustment circuit corresponding to the second fan responsive. At this time, even if the gear adjustment circuits corresponding to the first and third fans also receive adjustment and execution signals, their gears can remain unchanged because the gear adjustment circuits corresponding to the first and third fans are not effectively enabled. Therefore, the controller can adjust only the selected target fan using the shared adjustment and execution signals.

[0060] In this way, the fan selection circuit can first determine the target fan based on the analog signal, and then limit the actual gear adjustment circuits participating in the gear adjustment by the enable signal. The adjustment signal and execution signal output by the controller can further control the gear adjustment circuit to complete the gear adjustment of the target fan. Therefore, the adjustment signal and execution signal can be multiplexed among multiple gear adjustment circuits without causing unselected fans to adjust synchronously. This achieves independent gear adjustment of multiple fans while further reducing the occupation of controller interface resources and lowering the complexity of multi-fan control circuits.

[0061] Furthermore, in some embodiments, the execution signal can also be used to indicate the number of gear adjustments, enabling the target fan to complete one or more gear adjustments at once. Here, the gear can be a discrete control level representing the fan speed. Specifically, multiple gears can correspond to different fan speeds or different speed ranges. For example, multiple gears can include a stop gear, a low speed gear, a medium speed gear, and a high speed gear. Alternatively, multiple gears can also include gears one through ten, where the first gear corresponds to a lower speed and the tenth gear corresponds to a higher speed.

[0062] When a significant change in the target fan speed is required, the controller can send an execution signal indicating multiple speed adjustments. Correspondingly, the speed adjustment circuit for the target fan can continuously adjust the speed in the direction indicated by the adjustment signal, corresponding to the number of adjustments sent by the execution signal. For example, if the target fan is currently in the first speed position, the speed adjustment direction is increasing the speed, and the execution signal indicates two adjustments, the speed adjustment circuit for the target fan can adjust the target fan's speed from the first speed to the third speed. As another example, if the target fan is currently in the fourth speed position, the speed adjustment direction is decreasing the speed, and the execution signal indicates three adjustments, the speed adjustment circuit for the target fan can adjust the target fan's speed from the fourth speed back to the first speed.

[0063] The execution signal can represent the number of gear adjustments through one or more methods, such as the number of pulses, the number of edges, the duration, or the encoded state. For example, the execution signal can include multiple pulses, each pulse triggering one gear adjustment. Accordingly, an execution signal including one pulse can represent one gear adjustment; an execution signal including two pulses can represent two gear adjustments; and an execution signal including three pulses can represent three gear adjustments. In other examples, the execution signal can also represent the number of adjustments through its duration, and the gear adjustment circuit can determine the number of gears to be adjusted based on the duration of the execution signal and a preset time unit.

[0064] After the gear adjustment circuit corresponding to the target fan responds to the enable signal, it first determines the gear adjustment direction based on the adjustment signal, and then executes the gear adjustment according to the number of adjustments indicated by the execution signal. Specifically, when the adjustment signal indicates an increase in gear, the gear adjustment circuit corresponding to the target fan can increase the target fan's gear by the corresponding number of gears based on the number of adjustments indicated by the execution signal. When the adjustment signal indicates a decrease in gear, the gear adjustment circuit corresponding to the target fan can decrease the target fan's gear by the corresponding number of gears based on the number of adjustments indicated by the execution signal. Thus, the adjustment signal represents the direction of adjustment, and the execution signal represents the number of gears adjusted; the two work together to complete the multi-gear adjustment of the target fan.

[0065] In some embodiments, the gear adjustment circuit corresponding to the target fan can also perform gear adjustment in conjunction with the upper and lower gear limits of the target fan. For example, when the current gear of the target fan has reached the highest gear, even if the execution signal indicates to continue increasing the gear, the gear adjustment circuit corresponding to the target fan can keep the target fan at the highest gear. As another example, when the current gear of the target fan has reached the lowest gear, even if the execution signal indicates to continue decreasing the gear, the gear adjustment circuit corresponding to the target fan can keep the target fan at the lowest gear. This reduces the risk of control abnormalities caused by gear exceeding limits.

[0066] By using the execution signal to indicate the number of gear adjustments, the controller can specify not only the direction of gear adjustment but also the adjustment range. Therefore, the gear adjustment circuit corresponding to the target fan can complete multiple gear adjustments according to the required adjustment range. This allows for single-gear or continuous multi-gear speed adjustment of the target fan without adding an independent gear control port, improving the flexibility and efficiency of speed adjustment.

[0067] In some embodiments, the gear adjustment circuit may include a counter, enabling the gear changes of the target fan to be recorded and updated via count values. The counter is a circuit used to count based on an input signal and output a count value. Specifically, the counter can enter a countable state in response to an enable signal corresponding to the target fan, and in the countable state, it counts based on an execution signal. The counting direction of the counter can be determined by the adjustment signal. For example, when the adjustment signal indicates an increase in gear, the counter can increment based on the execution signal; when the adjustment signal indicates a decrease in gear, the counter can decrement based on the execution signal. Thus, the counter value can increase as the target fan gear increases, or decrease as the target fan gear decreases, thereby indicating the current gear position of the target fan.

[0068] In some embodiments, the execution signal may include one or more pulses. A counter can determine the amount of change in the count value based on the number of pulses in the execution signal. For example, the counter may perform a count once when the rising edge of the execution signal arrives. Accordingly, when the execution signal includes one rising edge, the counter's count value changes once; when the execution signal includes two rising edges, the counter's count value changes twice. Thus, the execution signal can both trigger gear adjustment and control the magnitude of gear changes through the number of pulses.

[0069] For example, the counter can be a reversible counter. For instance, the counter may include a 74LS190 counter chip or other counter devices capable of incrementing and decrementing. The counter may have an enable terminal, an increment / decrement control terminal, a clock input terminal, and a count output terminal. The enable terminal can receive an enable signal corresponding to the target fan, the increment / decrement control terminal can receive an adjustment signal, the clock input terminal can receive an execution signal, and the count output terminal can output the count value. Thus, the counter can change its count value according to the adjustment and execution signals when the enable signal is valid. For example, if the target fan is currently in the second gear, the counter's count value corresponds to the second gear; if the adjustment signal indicates an increase in gear and the execution signal includes two valid pulses, the counter can perform two increments, changing the count value to the value corresponding to the fourth gear.

[0070] like Figure 5 The schematic diagram of the fan control system shown illustrates that after obtaining the count value, the fan control system can further convert the count value into a specific speed signal through a speed setting circuit. The speed setting circuit is used to output the speed signal based on the count value. The speed setting circuit can include multiple preset speed voltages and selects a target voltage from these preset voltages as the speed signal based on the count value output by the counter. The multiple preset speed voltages can each correspond to multiple speeds of the fan. For example, the multiple preset speed voltages can include a first preset speed voltage, a second preset speed voltage, a third preset speed voltage, and a fourth preset speed voltage. The first preset speed voltage can correspond to the stop speed or low speed speed, the fourth preset speed voltage can correspond to the full speed speed speed, and the second and third preset speed voltages can each correspond to intermediate speeds between these two. Thus, the count value can first be converted into discrete voltage values, and different voltage values ​​then correspond to different speed speeds of the target fan.

[0071] In some embodiments, the gear setting circuit may include an analog multiplexer and a voltage divider circuit. The voltage divider circuit can provide multiple preset gear voltages, and the analog multiplexer can select one of the multiple input channels based on a count value, outputting the preset gear voltage corresponding to the selected input channel as the target voltage. For example, the analog multiplexer may use an ADG408 chip. The address input of the ADG408 chip can receive the count value output by a counter and select the corresponding channel based on the count value, so that the preset gear voltage of the corresponding channel is output as the gear signal. For example, when the count value corresponds to the first channel, the analog multiplexer can output the first preset gear voltage; when the count value corresponds to the fourth channel, the analog multiplexer can output the fourth preset gear voltage. In this way, the conversion between the count value and the gear signal can be achieved through hardware selection.

[0072] The speed control signal is an electrical signal used to indicate the target speed of the fan. The speed control signal can be a voltage signal, and different amplitude signals correspond to different fan speeds. For example, a 0V signal corresponds to the stop speed, one-third of the supply voltage corresponds to the low speed speed, two-thirds of the supply voltage corresponds to the medium speed speed, and the full speed speed corresponds to the maximum speed. Because the speed control signal is in analog voltage form, it can be easily converted into a PWM control signal suitable for the fan.

[0073] Furthermore, the gear shifting circuit corresponding to the target fan can receive the gear signal and convert it into a second PWM signal for driving the corresponding fan. The gear shifting circuit is used to convert the gear signal into a second PWM signal. Specifically, the gear shifting circuit can output a second PWM signal with a corresponding duty cycle or frequency based on the voltage amplitude of the gear signal. This second PWM signal can be directly used for the speed control of the target fan. In other words, the first PWM signal is mainly used to determine the target fan, while the second PWM signal is mainly used to drive the target fan to operate at the corresponding speed; their roles in the fan control system are different.

[0074] In some embodiments, the gear shifting circuit may include a PWM generator. The PWM generator can generate a second PWM signal with a corresponding duty cycle based on the input gear signal. For example, when the gear signal is 0V, the gear shifting circuit can output a second PWM signal with a 0% duty cycle; when the gear signal is one-third of the supply voltage, the gear shifting circuit can output a second PWM signal with a 30% duty cycle; when the gear signal is two-thirds of the supply voltage, the gear shifting circuit can output a second PWM signal with a 60% duty cycle; and when the gear signal is the supply voltage, the gear shifting circuit can output a second PWM signal with a 100% duty cycle. Exemplarily, the gear shifting circuit may include an LTC6992 chip or other voltage-controlled PWM generation circuit. Therefore, the higher the gear of the target fan, the larger the duty cycle of the second PWM signal output by the gear shifting circuit can be, and the speed of the target fan can be increased accordingly.

[0075] In this way, the speed adjustment circuit corresponding to the target fan can use a counter to save and update the speed state of the target fan. The speed setting circuit corresponding to the target fan can convert the count value into a discrete speed signal. The speed conversion circuit corresponding to the target fan can further convert the speed signal into a second PWM signal to drive the fan. Therefore, the controller does not need to continuously output independent speed control PWM signals for each fan, nor does it need to configure multiple speed control ports for each fan. It can achieve multi-speed adjustment of the target fan through a hardware link of count value—speed signal—second PWM signal, thereby further reducing the controller's PWM and interface resource usage and improving the stability of speed holding and speed adjustment.

[0076] When there are a large number of fans, the number of fans may exceed the maximum number of enable signals output by the signal conversion circuit, resulting in the remaining fans not being able to be driven. In some embodiments, this can be addressed by referring to... Figure 6 Multiple fans can be divided into at least two fan groups. Different fan groups can be divided according to the fans' installation location in the power electronic conversion device, their location in the air duct, their corresponding heat-generating components, or control requirements. For example, multiple fans close to a first power device can be divided into fan group 1, and multiple fans close to another power device can be divided into fan group L. As another example, multiple fans located in different air ducts can also be divided into different fan groups.

[0077] like Figure 6As shown, the controller can output multiple first PWM signals, namely PWM signal 1 to PWM signal L, through the PWM module. Different first PWM signals correspond to different fan groups. That is, PWM signal 1 can correspond to the first fan group, and PWM signal L can correspond to the Lth fan group. In this way, one first PWM signal does not need to correspond to a single fan, but can first correspond to a fan group, and then further determine the target fan within that fan group.

[0078] Each group of fans can be configured with a corresponding signal conversion circuit and a fan determination circuit. For example, the first group of fans is equipped with a signal conversion circuit and a fan determination circuit 1, and the Lth group of fans is equipped with a signal conversion circuit and a fan determination circuit L. The signal conversion circuit for the first group of fans can receive PWM signal 1 and convert it into a corresponding analog signal; the fan determination circuit 1 can determine the target fan in the first group of fans based on the preset voltage range of the analog signal. Similarly, the signal conversion circuit for the Lth group of fans can receive PWM signal L and convert it into a corresponding analog signal; the fan determination circuit L can determine the target fan in the Lth group of fans based on the preset voltage range of the analog signal.

[0079] In some embodiments, the number of fans in different fan groups may be the same or different. Figure 6 For example, the first fan group may include fan 1, fan 2 through fan N, and the Lth fan group may include fan 1, fan 2 through fan M. N and M can be the same or different. Correspondingly, the fan determination circuits for different fan groups can be configured with the same number of preset voltage ranges or with different numbers of preset voltage ranges. Therefore, the target fan determination method for each group can be flexibly set according to the number of fans in each fan group.

[0080] For example, when it is necessary to control a specific fan in the first fan group, the controller can output a PWM signal 1 through the PWM module. After the PWM signal 1 is converted into an analog signal by the signal conversion circuit corresponding to the first fan group, the fan determination circuit 1 can determine the target fan in the first fan group based on the preset voltage range of the analog signal. If the analog signal is within the preset voltage range corresponding to the second fan in the first fan group, then the fan determination circuit 1 can determine the second fan in the first fan group as the target fan. Similarly, when it is necessary to control a specific fan in the Lth fan group, the controller can output a PWM signal L through the PWM module, so that the fan determination circuit L can determine the target fan in the Lth fan group.

[0081] Figure 6The diagram also shows that the controller can output adjustment and execution signals via GPIO modules. These signals can be transmitted to the speed adjustment circuits within each fan group, causing the speed adjustment circuit selected by the corresponding fan determination circuit to perform speed adjustment. This part can cooperate with the enable signal and speed adjustment circuits in the aforementioned embodiments to further adjust the speed of the target fan after it has been determined.

[0082] In this embodiment, multiple fans can be grouped, and each fan group can be configured with a first PWM signal, a signal conversion circuit, and a fan determination circuit. Compared to configuring a separate PWM output or selection signal for each fan, this embodiment can expand the number of controllable fans by using a single first PWM signal for each group. Therefore, when the number of fans exceeds the maximum number of enable signals output by the signal conversion circuit, resulting in the remaining fans being unable to be driven, the control scale of the fan control system can be expanded by increasing the number of fan groups, while simultaneously reducing the occupancy of controller PWM and interface resources.

[0083] Continue reading Figure 6 After the target fan is determined, each fan group can also be configured with a speed adjustment link corresponding to each fan in the group, so as to adjust the speed of the selected target fan.

[0084] Specifically, such as Figure 6 As shown, the first group of fans can be equipped with multiple speed adjustment circuits, such as speed adjustment circuit 1, speed adjustment circuit 2 to speed adjustment circuit N, corresponding to the first, second to Nth fans in the first group of fans, respectively. Similarly, the Lth group of fans can also be equipped with multiple speed adjustment circuits, such as speed adjustment circuit 1, speed adjustment circuit 2 to speed adjustment circuit M, corresponding to the first, second to Mth fans in the Lth group of fans, respectively. Thus, different fans within each group of fans can have their speed adjusted through their corresponding speed adjustment circuits.

[0085] To reduce the controller's interface resource consumption, the controller can output shared adjustment and execution signals via GPIO modules. These signals can be transmitted to multiple speed control circuits within each fan group. Since these signals can be shared by all fan group speed control circuits, the controller does not need to configure separate adjustment and execution signal output ports for each fan. Although the adjustment and execution signals can be received by multiple speed control circuits, the actual speed control circuit that performs the speed adjustment is still determined by the enable signal. Taking the first fan group as an example, after PWM signal 1 is converted into an analog signal by the signal conversion circuit corresponding to the first fan group, the fan determination circuit 1 can output one of the following valid enable signals—enable signal 1, enable signal 2, or enable signal N—based on the preset voltage range of the analog signal.

[0086] When a gear adjustment circuit receives a valid enable signal, it enters a responsive state and responds to the adjustment and execution signals to perform gear adjustment. Gear adjustment circuits that do not receive a valid enable signal, even if they also receive the adjustment and execution signals, will maintain their original gear. Therefore, the shared adjustment and execution signals do not cause all fans to adjust synchronously; instead, they only act on the gear adjustment circuit selected by the enable signal.

[0087] For example, such as Figure 6 As shown, when the controller needs to adjust the second fan in the first fan group, the controller can output a PWM signal 1 corresponding to the first fan group via the PWM module. After the PWM signal 1 is converted into an analog signal by the signal conversion circuit corresponding to the first fan group, the analog signal to enable signal circuit 1 can output an enable signal 2, making the speed adjustment circuit 2 in the first fan group responsive. Subsequently, the controller outputs adjustment and execution signals via the GPIO module. The speed adjustment circuit 2 in the first fan group can respond to the adjustment and execution signals to change the speed signal 2 output by the corresponding speed setting circuit, and then output PWM 2 through the speed conversion circuit 2 to adjust the PWM signal received by the second fan speed control element. At the same time, the speed adjustment circuit 1, speed adjustment circuit N, and other disabled speed adjustment circuits in the first fan group can maintain their original speeds.

[0088] Similarly, when the controller needs to adjust the Mth fan in the Lth fan group, it can output a PWM signal L corresponding to the Lth fan group. After the PWM signal L is converted into an analog signal by the corresponding signal conversion circuit, the analog signal to enable signal circuit L can output an enable signal M, causing the speed adjustment circuit M in the Lth fan group to respond to the adjustment signal and the execution signal. Thus, different fan groups can each determine the target fan within their group through the corresponding first PWM signal, while the adjustment signal and the execution signal can still be multiplexed among multiple fan groups.

[0089] In some embodiments, when the controller needs to adjust the target fan within a target fan group, it can disable the first PWM signal corresponding to a non-target fan group or prevent the fan determination circuit corresponding to a non-target fan group from outputting a valid enable signal. Therefore, even if the adjustment signal and execution signal are transmitted to the gear adjustment circuit within each group, the gear adjustment circuit within the non-target fan group will not respond to the adjustment signal and execution signal, thereby reducing the risk of erroneous gear adjustment within the non-target fan group. In other embodiments, the controller can also output valid first PWM signals to different fan groups, enabling each fan group to determine its target fan and perform gear adjustment when the corresponding enable signal is valid, to accommodate scenarios where multiple heat-generating components require simultaneous speed adjustment.

[0090] In this manner, the controller can determine the fan group containing the target fan using different first PWM signals, and further enable the gear adjustment circuit corresponding to the target fan within that fan group using the fan determination circuit of that fan group. Simultaneously, the adjustment signal and execution signal can be transmitted to the gear adjustment circuit within each group, and the actual gear adjustment circuit responding to these signals is determined by the enable signal. Therefore, independent gear adjustment across fan groups and across individual fans can be achieved while multiplexing the adjustment and execution signals among multiple gear adjustment circuits, thereby further reducing the controller's GPIO interface resource usage and improving circuit reuse when controlling multiple fan groups.

[0091] To improve the reliability of target fan determination, in some embodiments, the fan control system can also perform feedback detection on the analog signal output by the signal conversion circuit. Specifically, the fan control system may include an analog-to-digital converter (ADC), which is a circuit or device used to convert analog quantities into digital quantities. The ADC can be a stand-alone ADC chip or an ADC module integrated into the controller. The input terminal of the ADC can be connected to the output terminal of the signal conversion circuit to acquire the analog signal output by the signal conversion circuit; the output terminal of the ADC can be connected to the controller to send a digital signal corresponding to the analog signal to the controller.

[0092] After receiving the digital signal, the controller can determine the actual value of the analog signal output by the signal conversion circuit. The digital signal can represent the voltage sample value of the analog signal, or the voltage value of the analog signal after sampling, filtering, and averaging. Therefore, the controller no longer estimates the magnitude of the analog signal solely based on the first output PWM signal, but can confirm whether the analog signal has reached the expected value through the digital signal fed back from the analog-to-digital converter.

[0093] After the controller identifies the target fan, it can further determine the target value corresponding to that fan. The target value is the value of the analog signal output by the controller's signal conversion circuit, and it can be determined based on a preset voltage range corresponding to the target fan. For example, the target value can be located within the preset voltage range corresponding to the target fan, and maintain a certain distance from both the upper and lower limits of that preset voltage range. This reduces the risk of the analog signal falling into adjacent preset voltage ranges, even if there are fluctuations in the analog signal. For example, if the preset voltage range corresponding to the target fan is 1.1V to 1.3V, the target value can be set to 1.2V or 1.25V, rather than being set near 1.1V or 1.3V.

[0094] In some embodiments, the controller can determine a target value based on the target fan and output a first PWM signal corresponding to the target value. After the signal conversion circuit converts the first PWM signal into an analog signal, the analog-to-digital converter converts the analog signal into a digital signal and feeds it back to the controller. The controller can adjust the signal parameters of the first PWM signal based on the deviation between the actual value of the analog signal represented by the digital signal and the target value, so that the analog signal changes towards the target value. The signal parameters of the first PWM signal may include at least one of frequency, duty cycle, pulse width, or period. For example, if the signal conversion circuit outputs an analog signal based on the frequency of the first PWM signal, the controller can adjust the frequency of the first PWM signal based on the digital signal to make the analog signal output by the signal conversion circuit closer to the target value. As another example, if the signal conversion circuit outputs an analog signal based on the duty cycle of the first PWM signal, the controller can adjust the duty cycle of the first PWM signal based on the digital signal to make the analog signal output by the signal conversion circuit closer to the target value.

[0095] In a specific example, the controller intends to select a second fan with a preset voltage range of 1.1V to 1.3V and a target value of 1.25V. If the digital signal fed back from the analog-to-digital converter indicates that the analog signal is currently approximately 1.18V, the controller can adjust the frequency or duty cycle of the first PWM signal to make the analog signal output from the signal conversion circuit continue to move closer to 1.25V. If the fed-back analog signal has stabilized near the target value, or has stabilized within the 1.1V to 1.3V range, the controller can consider that the analog signal meets the conditions for determining the second fan.

[0096] A normal analog signal indicates that it meets the conditions for determining the target fan. In some embodiments, the controller can determine that the analog signal is normal when the deviation between the digital signal representing the analog signal and the target value is less than or equal to an allowable deviation threshold. Alternatively, the controller can determine that the analog signal is normal when the digital signal representing the analog signal is within a preset voltage range corresponding to the target fan. When the analog signal is normal, the fan determination circuit can reliably determine the target fan based on the analog signal. Therefore, after determining that the analog signal is normal, the controller can output adjustment and execution signals to cause the gear adjustment circuit corresponding to the target fan to perform gear adjustment.

[0097] Correspondingly, an abnormal analog signal indicates that the analog signal does not meet the conditions for determining the target fan. The controller can determine an abnormal analog signal when the deviation between the digital signal representing the analog signal and the target value exceeds an allowable deviation threshold; or, the controller can determine an abnormal analog signal when the digital signal representing the analog signal is not within the preset voltage range corresponding to the target fan. If adjustment and execution signals continue to be output when the analog signal is abnormal, the fan determination circuit may select the wrong target fan, leading to the incorrect adjustment of the non-target fan's speed. Therefore, the controller can temporarily withhold adjustment and execution signals and instead output an alarm signal. The alarm signal can be used to indicate a risk of abnormality in the signal conversion circuit, the first PWM signal output link, the analog-to-digital converter, or the fan determination circuit. The alarm signal can be a level signal, a communication message, a fault code, or an indication signal, etc.

[0098] By setting up an analog-to-digital converter to provide feedback on the analog signal output from the signal conversion circuit, the controller can perform closed-loop adjustment of the first PWM signal based on the digital signal, making the analog signal more stably reach the target value. This improves the accuracy of the fan determination circuit in identifying the target fan. Furthermore, by outputting adjustment and execution signals only after determining that the analog signal is normal, the controller reduces the risk of false enable caused by analog signal deviation, component errors, or environmental changes. Outputting alarm signals when the analog signal is abnormal facilitates timely detection of control link anomalies, thereby improving the reliability of the target fan selection and speed adjustment process.

[0099] Further reading Figure 5 and Figure 6 To confirm whether each fan is rotating as expected, in some embodiments, each of the multiple fans can be equipped with a speed feedback element. The speed feedback element can be a component used to detect or generate a signal representing the fan speed. The speed feedback element can be located inside the fan or outside the fan and corresponds to the fan's rotating parts. Exemplarily, the speed feedback element can include at least one of a Hall sensor, photoelectric sensor, magnetic encoder, speed detection coil, or an existing speed feedback port inside the fan. Thus, each fan can report its actual operating status to the controller through its corresponding speed feedback element.

[0100] The fan speed signal is an electrical signal used to represent the actual speed of the fan. A speed feedback element can feed back the corresponding fan speed signal to the controller's GPIO module. The speed signal can be a pulse signal, a frequency signal, a level transition signal, or a digital signal processed by the speed feedback element. For example, the speed feedback element can output one or more pulses for each revolution of the fan. The controller can determine the actual speed of the corresponding fan based on the number of pulses received per unit time or the time interval between adjacent pulses. In this way, the controller can not only output control commands to the fan but also confirm whether the fan has actually reached the corresponding speed based on the speed signal.

[0101] In some embodiments, the controller can receive the speed signal through a general-purpose input / output interface, a counting interface, a capture interface, or a communication interface. For example, the controller can count the number of pulses in the speed signal within a preset detection window and determine the fan speed based on the number of pulses. Alternatively, the controller can capture the time interval between adjacent rising or falling edges of the speed signal and determine the fan speed based on this time interval. Thus, the controller can obtain the actual fan speed using either a counting method or a periodic measurement method, facilitating adaptation to different types of speed feedback elements.

[0102] The controller determines whether the fan speed is normal based on the speed signal, which may include determining whether the actual fan speed is within a preset normal range. After obtaining the actual fan speed, the controller can determine whether this actual speed is within the preset normal range. The preset normal range can be determined based on one or more factors such as the fan's target operating state, fan specifications, cooling requirements, or temperature detection results. For example, when the controller determines that a fan should be running based on temperature detection results, if the fan speed signal indicates that the actual speed is lower than the preset lower limit, or if no valid speed signal is detected within a preset time, the controller can determine that the fan speed is abnormal. As another example, when the controller determines that a fan should reduce its speed or stop running based on temperature detection results, if the fan speed signal indicates that the actual speed is still higher than the preset upper limit, the controller can also determine that the fan speed is abnormal. Thus, abnormal situations such as fan stoppage, stall, insufficient speed, or inability to reduce speed as instructed can be identified.

[0103] In some embodiments, the controller can also determine whether the fan speed is normal based on the deviation between the expected and actual fan speed. For example, the controller can determine the expected fan speed range based on temperature detection results and the actual fan speed based on the speed signal; when the deviation between the actual speed and the expected speed range exceeds an allowable deviation threshold, the controller can determine that the fan speed is abnormal. The allowable deviation threshold can be set based on factors such as fan speed control accuracy, fan inertia, speed stabilization time, or heat dissipation safety margin. For example, after the target fan is adjusted to a high-speed setting, the controller can read the speed signal after a preset stabilization time; if the actual speed is still significantly lower than the speed range corresponding to the high-speed setting, it can be determined that the target fan has not increased its speed as expected.

[0104] An abnormal signal is used to indicate an abnormal fan speed. When an abnormal fan speed is detected, the controller can output an abnormal signal, which can be at least one of the following: a level signal, a communication message, a fault code, an alarm indication signal, or a shutdown protection trigger signal. The abnormal signal can be sent to the main controller, display device, host computer, or protection circuit of the power electronic converter to indicate risks such as fan stall, stoppage, insufficient speed, excessive speed, or feedback circuit abnormality. In some cases, the power electronic converter can also perform power reduction operation, shutdown protection, or maintenance prompts based on the abnormal signal.

[0105] By setting a speed feedback element for each of the multiple fans, the controller can obtain the actual speed of each fan and determine whether the fan speed is normal based on the speed signal. Therefore, it can output abnormal signals in a timely manner when a fan does not operate as expected, a fan is stalled, a fan is aging, or the speed feedback link is abnormal. This allows the fan control system to not only select target fans and adjust their speeds, but also to perform feedback verification of the actual fan operation results, improving the ability to detect heat dissipation anomalies and reducing the risk of insufficient heat dissipation in power electronic converters due to fan malfunctions.

[0106] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0107] Please see Figure 7 , Figure 7 A schematic diagram of the specific circuit structure of a fan control system provided in one embodiment of this application is shown. Figure 7 Taking three fans as an example, namely fan 1, fan 2, and fan 3. The fan control system may include a controller, a signal conversion circuit, a fan determination circuit, and gear adjustment circuit, gear setting circuit, gear switching circuit, and speed control element respectively set for the three fans.

[0108] In this embodiment, the controller may include a PWM module and a GPIO module. The PWM module outputs a first PWM signal, which is used to transmit fan selection information. The GPIO module outputs an adjustment signal and an execution signal. The adjustment signal indicates the direction of gear adjustment (increasing or decreasing the gear), and the execution signal triggers the corresponding gear adjustment circuit to perform one or more gear adjustments.

[0109] The first PWM signal output by the controller is first input to the signal conversion circuit. Figure 7 The signal conversion circuit shown may include transistor Q1, frequency-to-voltage converter U6, and peripheral components such as resistors R31, R14, R12, R13, capacitors C1, C2, and C3. The first PWM signal can be input to transistor Q1 via resistor R31. Transistor Q1, along with resistors R14 and capacitor C3, can perform level conversion and waveform processing on the first PWM signal, and then input the processed pulse signal to the frequency-to-voltage converter U6.

[0110] For example, the frequency-to-voltage converter U6 can be an LM2907 or other device capable of converting the input signal frequency into an analog voltage. Resistors R12 and R13, capacitors C1 and C2, etc., work with the frequency-to-voltage converter U6 to determine the conversion relationship between frequency and output voltage and to smooth the output voltage. Thus, when the duty cycle of the first PWM signal remains constant while the frequency changes, the signal conversion circuit can output analog signals Uout with different voltage values. Because capacitors C1 and C2 undergo charging and discharging processes, the analog signal Uout can gradually change to a corresponding stable voltage after the frequency of the PWM signal changes, rather than jumping instantaneously.

[0111] The analog signal Uout output from the signal conversion circuit is further input to the fan determination circuit. The fan determination circuit can be specifically implemented as an analog signal to enable signal circuit, including voltage detection chips U3, U4, U5, U7, U12, and U13, as well as logic gates U8A, U8B, U10B, and inverters U9A, U9B, and U11B. The output terminals of each voltage detection chip can also be connected to external components such as resistors R11, R15 to R19 to form a stable logic level.

[0112] Among them, voltage detection chips U3, U4, U5, U7, U12, and U13 can have different voltage detection thresholds. For example, voltage detection devices with different detection thresholds, such as BU4809, BU4811, BU4813, and BU4815, can be used. Different voltage detection chips determine whether the analog signal Uout reaches the corresponding preset voltage threshold and output the corresponding detection result.

[0113] To construct a preset voltage range from multiple voltage thresholds, the detection results of two adjacent voltage thresholds can be input to the corresponding logic gates. Taking the first fan as an example, voltage detection chips U3 and U4 can correspond to the lower and upper limits of the preset voltage range for the first fan, respectively, and their detection results can be input to logic gate U8A. When the analog signal Uout is between the lower and upper limits, the output states of U3 and U4 are different, and logic gate U8A can output the corresponding logic signal accordingly. This logic signal, after being processed by inverter U9A, can form enable signal 1.

[0114] Similarly, voltage detection chips U5 and U7, logic gate U8B, and inverter U9B can be used to generate enable signal 2; voltage detection chips U12 and U13, logic gate U10B, and inverter U11B can be used to generate enable signal 3. Logic gates U8A, U8B, and U10B can be provided, for example, by a 74LS136 XOR gate chip, and inverters U9A, U9B, and U11B can be provided, for example, by a 74LS04 NOT gate chip.

[0115] In this embodiment, enable signals 1 to 3 can be active low. When the analog signal Uout is within the preset voltage range corresponding to the first fan, enable signal 1 remains active low, while enable signals 2 and 3 remain inactive high. When the analog signal Uout is within the preset voltage range corresponding to the second fan, enable signal 2 remains active low. When the analog signal Uout is within the preset voltage range corresponding to the third fan, enable signal 3 remains active low. Therefore, the fan determination circuit can convert the voltage range of the analog signal Uout into the corresponding fan selection result.

[0116] In the subsequent stage of the fan determination circuit, the first fan, the second fan, and the third fan are each equipped with a gear adjustment circuit. Specifically, the first fan corresponds to gear adjustment circuit 1, gear setting circuit 1, and gear switching circuit 1; the second fan corresponds to gear adjustment circuit 2, gear setting circuit 2, and gear switching circuit 2; and the third fan corresponds to gear adjustment circuit 3, gear setting circuit 3, and gear switching circuit 3.

[0117] Gear adjustment circuit 1 may include counter U1, gear adjustment circuit 2 may include counter U14, and gear adjustment circuit 3 may include counter U16. Counters U1, U14, and U16 may be, for example, 74LS190 reversible counters. The enable terminal of each counter receives enable signal 1, enable signal 2, and enable signal 3, respectively. The counting direction control terminal of each counter can receive the adjustment signal output from the GPIO module, and the clock input terminal of each counter can receive the execution signal output from the GPIO module.

[0118] In this way, although the adjustment signal and the execution signal can be transmitted to the three counters simultaneously, only the counter that receives a valid enable signal can respond to the adjustment signal and the execution signal. For example, when enable signal 2 is valid, counter U14 can determine whether to increment or decrement based on the adjustment signal, and change its count value when the valid edge of the execution signal arrives. Counters U1 and U16, being disabled, can maintain their original count values.

[0119] In some embodiments, the execution signal may include one or more clock pulses, each valid pulse causing the enabled counter to change its count value once. Therefore, when the execution signal includes three valid pulses, the enabled counter can perform three consecutive counts. The counter's count value can thus represent the current speed of the corresponding fan, or it can remain at the adjusted speed even after the enable signal fails.

[0120] The count value output by the counter is further input to the corresponding gear setting circuit. Taking gear setting circuit 1 as an example, gear setting circuit 1 may include an analog multiplexer S1 and a voltage generation network composed of resistors R1 to R6. Resistors R1 to R6 can provide multiple different preset gear voltages, and each preset gear voltage is input to a different input channel of the analog multiplexer S1. The multiple counting output terminals of counter U1 can be connected to the address input terminals of analog multiplexer S1, so that analog multiplexer S1 selects the corresponding input channel according to the count value and outputs the preset gear voltage corresponding to the input channel as gear signal 1.

[0121] Similarly, gear setting circuit 2 may include an analog multiplexer S2 and a voltage generation network composed of resistors R7, R8, R21 to R24, etc., and gear setting circuit 3 may include an analog multiplexer S3 and a voltage generation network composed of resistors R25 to R30, etc. Analog multiplexers S2 and S3 output gear signal 2 and gear signal 3 respectively based on the count values ​​output by counters U14 and U16.

[0122] For example, analog multiplexers S1, S2, and S3 can be implemented using an ADG408 analog multiplexer. The ADG408 may include eight input channels, a common output, and three address inputs. When the three address inputs receive different three-bit address data, they can select one channel from the eight input channels. Thus, the counter output value can be used as address data, enabling the gear setting circuit to select the target voltage corresponding to the current gear from multiple preset gear voltages.

[0123] After the gear setting circuit outputs the gear signal, the gear conversion circuit can further convert the gear signal into a PWM signal for fan speed control. Specifically, gear conversion circuit 1 may include a PWM generator U2, which outputs PWM1 according to gear signal 1; gear conversion circuit 2 may include a PWM generator U15, which outputs PWM2 according to gear signal 2; gear conversion circuit 3 may include a PWM generator U17, which outputs PWM3 according to gear signal 3.

[0124] PWM generators U2, U15, and U17 can generate PWM signals with corresponding duty cycles based on the voltage amplitude of the gear signal. The higher the voltage of the gear signal, the larger the duty cycle of the generated PWM signal can be, and the higher the corresponding fan speed can be. PWM1, PWM2, and PWM3 are input to the speed control elements of the first, second, and third fans, respectively, so that the corresponding fans operate at the corresponding gear.

[0125] It should be noted that the first PWM signal output by the controller's PWM module plays a different role from PWM1 to PWM3. The first PWM signal output by the controller is mainly used to determine the target fan to be controlled; PWM1 to PWM3 can be used as the aforementioned second PWM signal, mainly used to control the actual speed of the corresponding fan.

[0126] Therefore, the circuit provided in this embodiment forms a complete control link: first PWM signal—analog signal Uout—enable signal—count value—gear signal—second PWM signal. The controller can use one first PWM signal to select the target fan among the three fans, and use the shared adjustment signal and execution signal to adjust the gear of the target fan. At the same time, each counter can maintain the gear state of the corresponding fan, so that after the controller switches to other target fans, the fans that have been adjusted can continue to run at the original gear.

[0127] To show more clearly Figure 7 For the gear adjustment circuit and gear setting circuit, please refer to [link / reference]. Figure 8 Taking gear adjustment circuit 1 and gear setting circuit 1 as examples, Figure 8 The connection structure of counter U1, analog multiplexer S1 and its peripheral circuits is shown.

[0128] In some embodiments, counter U1 may be a 74LS190 reversible counter, including a counting enable terminal CTEN, a counting direction control terminal D / U, a clock input terminal CLK, and counting output terminals QA, QB, and QC. The counting enable terminal CTEN receives an enable signal 1, the counting direction control terminal D / U receives an adjustment signal, and the clock input terminal CLK receives an execution signal. When enable signal 1 is valid, counter U1 can update its count value according to the direction indicated by the adjustment signal, triggered by the execution signal.

[0129] The analog multiplexer S1 can be an ADG408 analog multiplexer, including address input terminals A0, A1, and A2, multiple input channels S1 to S8, and a common output terminal D. The counting output terminals QA, QB, and QC of the counter U1 are connected to the address input terminals A0, A1, and A2 of the analog multiplexer S1, respectively. The multiple input channels S1 to S8 can be connected to different preset voltage levels formed by resistors R1 to R6. The analog multiplexer S1 selects the corresponding input channel based on the count value output by the counter U1 and outputs the corresponding preset voltage level through the common output terminal D as the level signal 1.

[0130] Figure 7 Other gear adjustment circuits and gear setting circuits in the system can be adopted with... Figure 8 Circuit structures that are the same or similar to those shown will not be described again here.

[0131] based on Figure 7 The specific circuit structure shown below, in conjunction with... Figure 9 Describe a specific fan control process. Figure 9 In the diagram, PWM represents the first PWM signal output by the PWM module of the controller, Uout represents the analog signal output by the signal conversion circuit, U_D represents the adjustment signal, CLK represents the execution signal, EN1, EN2 and EN3 represent enable signal 1, enable signal 2 and enable signal 3 respectively, and PWM1, PWM2 and PWM3 represent the second PWM signals input to the speed control elements of the three fans respectively.

[0132] exist Figure 9 In the example shown, the duty cycle of the first PWM signal can remain constant. The controller adjusts the frequency of the first PWM signal in stages, causing the analog signal Uout to sequentially enter the preset voltage ranges corresponding to the three fans. Simultaneously, the adjustment signal U_D can remain at the same level, for example, in a state indicating an increased speed. Enable signals EN1 to EN3 are active at a low level.

[0133] At t=0s, the controller begins outputting the first PWM signal. This first PWM signal can be a 1kHz PWM wave with a 50% duty cycle, and the signal conversion circuit begins frequency-to-voltage conversion. At this time, the initial value of the analog signal Uout is close to 0V, and has not yet reached the preset voltage range corresponding to any fan. EN1, EN2, and EN3 are all high and in an invalid state, and the execution signal CLK has not yet generated a valid pulse. Therefore, counters U1, U14, and U16 all maintain their initial count values, and PWM1, PWM2, and PWM3 maintain their corresponding initial states.

[0134] During the period from t=0s to t=0.029s, as the first PWM signal is continuously input, the capacitor in the signal conversion circuit gradually charges, and the analog signal Uout gradually increases from 0V. Since Uout remains below 0.9V during this period and has not yet stabilized within the preset voltage range corresponding to the first fan, EN1, EN2, and EN3 remain inactive, and none of the speed adjustment circuits respond to the adjustment signal U_D or the execution signal CLK. This start-up waiting process prevents the fan from being mistakenly selected before the signal conversion circuit has stabilized. Specifically, this process is manifested as follows: voltage detection chip U3 detects Uout below 0.9V and outputs a low level; voltage detection chip U4 detects Uout below 1.1V and outputs a low level; voltage detection chip U5 detects Uout below 1.1V and outputs a low level; voltage detection chip U7 detects Uout below 1.3V and outputs a low level; voltage detection chip U12 detects Uout below 1.3V and outputs a low level; and voltage detection chip U13 detects Uout below 1.5V and outputs a low level. At this time, the voltage levels received by U8A, U8B, and U10B are all low, so the output signals of U8A, U8B, and U10B are all low, and the output signals EN1, EN2, and EN3 of the NOT gate circuits U9A, U9B, and U11B are all high.

[0135] At t=0.029s, the analog signal Uout enters the preset voltage range corresponding to the first fan, for example, the voltage range of approximately 0.9V to 1.1V. Voltage detection chips U3 and U4, and their subsequent logic circuits accordingly, change EN1 from high to low, making counter U1 responsive; EN2 and EN3 remain high, indicating an invalid state. At this time, U8A performs an XOR operation on the output signals of voltage detection chips U3 and U4, obtaining a high level. This high level is then inverted by U9A, U9B, and U11B, outputting a low-level signal, i.e., EN1. Voltage detection chip U5 detects Uout below 1.3V and outputs a low level; voltage detection chip U7 detects Uout below 1.3V and outputs a low level; voltage detection chip U12 detects Uout below 1.3V and outputs a low level; voltage detection chip U13 detects Uout below 1.5V and outputs a low level. At this time, the voltage levels received by U8B and U10B are both low, while the output signals EN2 and EN3 of the NOT gates U9B and U11B are both high.

[0136] During the period from t=0.029s to t=0.1s, Uout remains relatively stable within the preset voltage range corresponding to the first fan. EN1 remains active, while EN2 and EN3 signals remain at a high level. However, no valid pulse is generated by CLK during this period. Therefore, although counter U1 is enabled, its count value does not change, and gear signal 1 and PWM1 remain in their original states. This demonstrates that the enable signal is only used to identify the fan capable of responding to gear adjustment; the fan's gear will only be changed when the execution signal arrives. Specifically, during this process, the controller does not output adjustment and execution signals to counter U1 via the GPIO module. Therefore, the count value of counter U1 is 0, meaning that QD, QC, QB, and QA of counter U1 remain low (0000). Since QD, QC, QB, and QA of counter U1 remain at 0000, channel 1 of analog multiplexer S1 is selected, and the voltage signal of channel 1 is 0V, which is output to gear switching circuit 1. Since the voltage of the input gear shifting circuit 1 is 0V, its output PWM signal has a 0% duty cycle, i.e., a low level, thus preventing the first fan from rotating. Similarly, during the period t=0.029~0.1s, the count values ​​of counters U14 and U16 are 0, meaning that QD, QC, QB, and QA of counters U14 and U16 remain at a low level, i.e., 0000. Because QD, QC, QB, and QA of counters U14 and U16 remain at 0000, channel 1 of analog multiplexers S2 and S3 is selected. The voltage signal of channel 1 is 0V, which is output to gear shifting circuits 2 and 3. Since the voltage of the input gear shifting circuits 2 and 3 is 0V, the duty cycle of the PWM signals output by these two circuits is 0%, i.e., a low level, thus preventing the second and third fans from rotating.

[0137] At t=0.1s, the controller adjusts the frequency of the first PWM signal, increasing it from 1kHz to 1.2kHz while maintaining a constant 50% duty cycle, thus raising the target output voltage of the signal conversion circuit. Due to the influence of the resistors and capacitors in the signal conversion circuit, Uout gradually changes from the voltage range corresponding to the first fan to the voltage range corresponding to the second fan.

[0138] From t=0.1 to t=0.11s, since Uout never exceeds 1.1V, the EN1 signal remains low, while the EN2 and EN3 signals remain high. During this time, the controller does not output adjustment or execution signals to counter U1 via the GPIO module, so the count value of counter U1 remains 0, and the count values ​​of counters U14 and U16 also remain 0. Therefore, from t=0.1 to 0.11s, fans 1 through 3 remain stopped.

[0139] At t=0.11s, Uout enters the preset voltage range corresponding to the second fan, for example, the voltage range of approximately 1.1V to 1.3V. At this time, EN1 returns to the high-level invalid state, EN2 becomes the low-level active state, and counter U14 enters the responsive state. Since counter U1 is no longer enabled, its count value will not change even if a CLK pulse appears subsequently. This process can specifically include: voltage detection chip U5 detects that Uout is higher than 1.1V and outputs a high level; voltage detection chip U7 detects that Uout is lower than 1.3V and outputs a low level. At this time, U8B performs an XOR operation on the output signals of voltage detection chip U5 and voltage detection chip U7 to obtain a high level. This high level is then inverted by a 74LS04D NOT gate chip and outputs a low-level signal, i.e., EN2. Voltage detection chip U3 detects that Uout is higher than 0.9V and outputs a high level; voltage detection chip U4 detects that Uout is higher than 1.1V and outputs a high level; voltage detection chip U12 detects that the input voltage is lower than 1.3V and outputs a low level; voltage detection chip U13 detects that the input voltage is lower than 1.5V and outputs a low level. At this time, the levels received by the two-input XOR gate chips U8B and U10B are both high and both are low, respectively, and the output signals EN1 and EN3 of the NOT gate circuits U9A and U11B are both high.

[0140] During the period from t=0.11s to t=0.15s, EN2 remains active, and EN1 and EN3 signals remain high. However, CLK has not yet generated a valid pulse, so counter U14 retains its original count value, counters U1 and U16 remain disabled, and PWM2 remains in its initial state. This period can be used as a stable waiting time after the target fan switches.

[0141] At t=0.15s, the GPIO module outputs multiple CLK pulses. Figure 9 The execution signal shown can include three valid pulses. Since only EN2 is valid at this time, only counter U14 responds to the CLK pulse. Counter U14 performs two consecutive counts according to the gear adjustment direction represented by U_D, changing its count value by two gears.

[0142] After the counter U14's count value changes, the analog multiplexer S2 selects the corresponding preset voltage level based on the new count value and outputs a new voltage level signal 2. The PWM generator U15 further generates a PWM2 with a corresponding duty cycle based on the voltage level signal 2. Figure 9 As can be seen, PWM2 starts outputting continuous pulse signals after t is approximately 0.15s, indicating that the second fan has been adjusted to the corresponding speed setting.

[0143] Meanwhile, although counters U1 and U16 are also connected to the adjustment signal U_D and the execution signal CLK, since EN1 and EN3 are both invalid, counters U1 and U16 will not respond to the aforementioned CLK pulse. Therefore, PWM1 and PWM3 will not change accordingly, avoiding the erroneous synchronization adjustment of the first and third fans.

[0144] During the period from t=0.15s to t=0.2s, Uout remains within the preset voltage range corresponding to the second fan, and EN2 remains active. After the CLK pulse ends, counter U14 maintains the adjusted count value, analog multiplexer S2 continues to output the corresponding speed signal 2, and PWM generator U15 also continues to output PWM2 with the corresponding duty cycle. Therefore, even if the execution signal returns to an invalid state, the second fan can still maintain the adjusted speed level.

[0145] At t=0.2s, the controller readjusts the frequency of the first PWM signal, increasing it from 1.2kHz to 1.4kHz while maintaining a 50% duty cycle. This causes Uout to increase from the voltage range corresponding to the second fan to the voltage range corresponding to the third fan. When Uout enters the preset voltage range corresponding to the third fan, EN2 returns to a high-level inactive state, EN3 becomes a low-level active state, and counter U16 enters a responsive state.

[0146] It should be noted that EN2 failure only indicates that counter U14 no longer responds to subsequent adjustment and execution signals; it does not clear the count value already stored in counter U14. Therefore, as Figure 9 As shown, after the target fan is switched from the second fan to the third fan, PWM2 still maintains the original pulse output, and the second fan can continue to run at the previously set speed.

[0147] During the period from t=0.2s to t=0.25s after EN3 becomes active, counter U16 waits for the execution signal CLK. Since no valid CLK pulse has appeared during this period, the count value of counter U16 and PWM3 remain in their initial state.

[0148] At t=0.25s, the GPIO module outputs multiple CLK pulses again. Figure 9 The execution signal shown may include, for example, four valid pulses. Since EN3 is valid at this time, counter U16 performs three consecutive counts according to the gear adjustment direction represented by U_D. Analog multiplexer S3 selects the corresponding preset gear voltage according to the updated count value and outputs gear signal 3. PWM generator U17 further updates PWM3 according to gear signal 3.

[0149] exist Figure 9In the example shown, the updated PWM3 can have a larger duty cycle, such as close to or reaching 100%. Therefore, PWM3 can be represented as a continuous high level in the diagram, indicating that the third fan is adjusted to a higher speed or full speed. At the same time, PWM2 maintains the previously set duty cycle, while PWM1 continues to maintain its initial state because it did not receive a CLK pulse during the period when EN1 is active.

[0150] During the period from t=0.25s to t=0.3s, EN3 remains active, counter U16 retains the updated count value, and PWM3 maintains the adjusted output state. Thus, the controller has sequentially completed the selection and speed adjustment of the first fan, the second fan, and the third fan.

[0151] Depend on Figure 9 As shown in the process, the first PWM signal is used to change the preset voltage range of the analog signal Uout to select the corresponding target fan; the adjustment signal U_D is used to indicate the direction of gear adjustment; and the execution signal CLK is used to control the actual gear change of the target fan. After the target fan is switched, the counters corresponding to other fans can maintain their original count values, allowing each fan to maintain its set speed. Therefore, multiple fans can share the adjustment and execution signals while still achieving independent gear adjustment.

[0152] It should be noted that, Figure 8 and Figure 9 This paper primarily uses the scenario of multiple fans belonging to the same fan group as an example to explain the specific structure and control process of each circuit within a single fan group. In embodiments where multiple fans are divided into at least two fan groups, each fan group can be configured with... Figure 8 The signal conversion circuit, fan determination circuit, gear adjustment circuit, gear setting circuit, and gear shifting circuit shown are identical or similar, and can be configured according to... Figure 9 The control process shown describes how to determine the target fan and adjust its speed within the fan group. Different fan groups can receive different first PWM signals from the controller to determine the target fan within their respective groups; the adjustment and execution signals output by the controller can be shared by the speed adjustment circuits within different fan groups. Therefore, the structure, connection relationships, and operation of the circuits in multiple fan groups can be found in [reference needed]. Figure 8 and Figure 9 The relevant descriptions of the corresponding embodiments will not be repeated here.

[0153] See Figure 10 , Figure 10 This is a schematic flowchart of a fan control method provided in an embodiment of this application.

[0154] This application provides a fan control method, which includes steps S101-S103: S101: Output the first PWM signal based on the temperature detection result.

[0155] S102: Convert the first PWM signal into an analog signal.

[0156] S103: Determine the target fan from among multiple fans based on the preset voltage range corresponding to the analog signal. Different preset voltage ranges correspond to different fans.

[0157] It is understood that the fan control method can be executed by the fan control system in any of the foregoing embodiments. The specific structure and working principle of each of the foregoing devices can be referred to the relevant descriptions in the fan control system embodiments, and will not be repeated here.

[0158] When executing this fan control method, the controller can first acquire the temperature detection results and determine the fan that needs to be controlled based on these results. The temperature detection results can indicate the temperature status of the corresponding heat-generating component. When the temperature of a heat-generating component changes and the corresponding fan needs to be adjusted, the controller can output a first PWM signal corresponding to that fan.

[0159] The first PWM signal can be used to carry fan selection information. Different first PWM signals can have different signal parameters such as frequency, duty cycle, pulse width, or period, and correspond to different fans. Therefore, the controller can indicate the fan that needs to be controlled by adjusting the signal parameters of the first PWM signal, without having to output selection signals corresponding to multiple fans one by one.

[0160] Subsequently, the first PWM signal can be converted into an analog signal. The signal conversion circuit can output an analog signal with corresponding values ​​based on the signal parameters of the first PWM signal. For example, an analog signal with a corresponding voltage value can be generated based on the frequency or duty cycle of the first PWM signal. In this way, the fan selection information carried in the first PWM signal can be converted into an analog signal that facilitates subsequent interval determination.

[0161] After receiving the analog signal, the fan determination circuit can identify the preset voltage range corresponding to the analog signal and determine the fan corresponding to that preset voltage range as the target fan. Different preset voltage ranges correspond to different fans. For example, when the analog signal is in the first preset voltage range, the first fan can be determined as the target fan; when the analog signal is in the second preset voltage range, the second fan can be determined as the target fan. For details on how the preset voltage ranges are set and their correspondence with each fan, please refer to the relevant descriptions in the aforementioned fan control system embodiment.

[0162] Therefore, this fan control method can generate a corresponding first PWM signal based on the temperature detection result, and determine the target fan among multiple fans by determining the preset voltage range of the analog signal obtained by converting the first PWM signal. Compared with the method of transmitting multiple fan selection signals through multiple output ports, the embodiments of this application can reduce the occupation of PWM resources or interface resources during multi-fan control.

[0163] In some embodiments, such as Figure 11 As shown in the illustration, this application also provides a power electronic conversion device, which includes a fan control system and a heat-generating component according to any of the above embodiments. The fan control system includes multiple fans and is used to determine a target fan among the multiple fans based on the temperature detection result of the heat-generating component. The target fan is used to dissipate heat from the heat-generating component. For the specific structure of the fan control system, the method of determining the target fan, and the corresponding control process, please refer to the relevant descriptions in the foregoing embodiments, which will not be repeated here.

[0164] A power electronic conversion device can be a device used to realize electrical energy conversion. For example, a power electronic conversion device may include an electric vehicle charging device, a medium-voltage direct-connected inverter, a medium-voltage direct-connected energy storage device, or a medium-voltage direct-connected static var generator, etc. During operation, some components in the power electronic conversion device will generate heat, and therefore can serve as heat-generating components in this embodiment. Exemplarily, the heat-generating component may include at least one of a power semiconductor device, a magnetic device, and a capacitor.

[0165] The fan control system includes multiple fans. These fans can be installed inside the power electronic converter and arranged according to the location of the heat-generating components, the airflow structure, or heat dissipation requirements. For example, at least some fans can be located near the heat-generating components to create airflow over them; at least some fans can also be located in the airflow ducts, inlets, or outlets of the power electronic converter to dissipate the heat generated by the heat-generating components.

[0166] During the operation of the power electronic converter, the temperature detection results of the heating components can be obtained. These results can be acquired by temperature sensors located on or near the heating components, or provided by other control units within the power electronic converter. The fan control system can then determine the target fan from among multiple fans based on these temperature detection results.

[0167] The target fan can be a fan that corresponds to the current cooling requirements of the heat-generating component. Once the target fan is determined, it can operate and create airflow through the heat-generating component, or expel hot air near the heat-generating component, thereby cooling the component. For example, when the temperature of a heat-generating component rises, the fan control system can identify the fan corresponding to that component as the target fan and utilize it to enhance the cooling of that component.

[0168] In some embodiments, the power electronic converter may include multiple heat-generating components. Different fans may correspond to different heat-generating components or they may all correspond to the same heat-generating component. The fan control system can determine the target fan that needs to participate in heat dissipation based on the temperature detection results of each heat-generating component, thereby matching multiple fans with the actual heat dissipation requirements inside the power electronic converter.

[0169] Therefore, the power electronic converter can utilize a fan control system to select the appropriate target fan based on the temperature detection results of the heat-generating component, and the target fan will dissipate heat from the heat-generating component. This satisfies the heat dissipation requirements of the device while reducing the occupation of controller PWM resources or interface resources during multi-fan control.

[0170] See Figure 12 , Figure 12 This is a structural block diagram of a controller provided in an embodiment of this application.

[0171] This application also provides a controller, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the fan control method provided in the above embodiments.

[0172] The controller may include a memory 110, a processor 120, and a communication interface 130. The memory 110, the processor 120, and the communication interface 130 are connected through internal connection paths.

[0173] The memory 110 is used to store computer programs, which in some implementations may include code for implementing the methods of the embodiments of this application.

[0174] The processor 120 executes the computer program stored in the memory 110 to control the communication interface 130 to receive input data and information, and output operation results and other data. In some implementations, when the solutions of the embodiments of this application are implemented by software or firmware, the computer program used to implement the solutions of the embodiments of this application can be stored in the processor 120 and executed by the processor 120.

[0175] The memory 110 may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory may be random access memory (RAM). It should be noted that the memory 110 described herein is intended to include, but is not limited to, any memory of these and other suitable types. As an example, the memory 110 includes random access memory (RAM), cache memory, and read-only memory (ROM). The memory 110 stores a computer program that can be executed by processor 120, causing processor 120 to implement the steps of any of the methods described above.

[0176] The processor 120 can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 120 can be any conventional processor.

[0177] In implementation, each step of the above method can be completed by the integrated logic circuitry of the hardware in the processor 120 or by instructions in software form. The method disclosed in the embodiments of this application can be directly implemented by the hardware processor, or by a combination of hardware and software modules in the processor 120. The software modules can be located in mature storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in the memory 110, and the processor 120 reads the information in the memory 110 and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0178] In some implementations, in addition to the hardware units described above, the controller may also include software modules, such as an operating system, a Basic Input Output System (BIOS), and application software.

[0179] An operating system is used to manage one or more of the hardware and software resources of a controller; it is the kernel and foundation of the controller. The operating system handles fundamental tasks such as managing and configuring memory, determining the priority of system resource allocation and demand, controlling input and output devices, operating the network, and managing the file system. To facilitate user operation, most operating systems provide a user interface for interaction with the system.

[0180] The BIOS is used to perform hardware initialization during the power-on boot phase and to provide runtime services for the operating system and applications. In some implementations, the BIOS can also monitor and display processor temperature and execute temperature protection strategies.

[0181] Application software, also known as an application program, can be understood as software written for a specific user application purpose, and is one of the main categories of computer software. For example, application software can be a program used to achieve purposes such as power control and temperature management.

[0182] It is understood that the specific examples in this application are only intended to help those skilled in the art better understand the implementation of this application, and are not intended to limit the scope of protection of this application.

[0183] It is understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this application.

[0184] It is understood that the various implementation methods described in this application can be implemented individually or in combination, and this application does not limit them.

[0185] Unless otherwise stated, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "one or more" as used in this application includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0186] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0187] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes and beneficial effects of the embodiments described above can be referred to the corresponding processes and beneficial effects in other embodiments, and will not be repeated here.

[0188] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0189] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the technical solution in this application, depending on actual needs.

[0190] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0191] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, essentially, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0192] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A fan control system, characterized by, include: Multiple fans; The controller is configured to output a first PWM signal based on the temperature detection result; A signal conversion circuit, connected to the controller, is used to convert the first PWM signal into an analog signal; A fan determination circuit, connected to the signal conversion circuit, is used to determine a target fan among the plurality of fans based on the preset voltage range corresponding to the analog signal; wherein different preset voltage ranges correspond to different fans.

2. The fan control system of claim 1, wherein, The controller is also configured to output regulation signals and execution signals; The fan control system also includes multiple speed adjustment circuits, each of which corresponds to one of the multiple fans. The fan determination circuit is used to convert the analog signal into an enable signal corresponding to the target fan; The gear adjustment circuit corresponding to the target fan is configured to: respond to the enable signal, determine the gear adjustment direction according to the adjustment signal, and perform gear adjustment of the target fan according to the gear adjustment direction based on the execution signal.

3. The fan control system according to claim 2, characterized in that, The fan is configured with multiple speed settings; the execution signal is also used to indicate the number of times the speed settings are adjusted. The gear adjustment circuit of the target fan is further configured to: adjust the gear by the number of adjustments indicated by the execution signal according to the gear adjustment direction.

4. The fan control system according to claim 2, characterized in that, The gear adjustment circuit includes a counter, which is used to determine a count value based on the execution signal; The fan control system further includes: multiple gear setting circuits and multiple gear switching circuits, wherein each of the multiple gear setting circuits corresponds to one of the multiple fans, and each of the multiple gear switching circuits corresponds to one of the multiple fans. The gear setting circuit corresponding to the target fan is used to select the target voltage as the gear signal from a plurality of preset gear voltages according to the count value; the gear conversion circuit corresponding to the target fan is used to convert the gear signal into a second PWM signal to drive the corresponding fan.

5. The fan control system according to claim 2, characterized in that, The plurality of fans are divided into at least two groups of fans; Each group of fans is connected to the corresponding signal conversion circuit and the fan determination circuit; The controller is configured to output multiple first PWM signals, with different first PWM signals corresponding to different fan groups.

6. The fan control system according to claim 5, characterized in that, Each fan group also includes multiple speed adjustment circuits, each corresponding to the fan in the fan group; The controller is also configured to output the adjustment signal and the execution signal to the gear adjustment circuit within each group; The gear adjustment circuit, which is enabled by the fan determination circuit of the corresponding fan group, responds to the adjustment signal and the execution signal to perform gear adjustment.

7. The fan control system according to claim 2, characterized in that, It also includes an analog-to-digital converter, connected to the output of the signal conversion circuit, for converting the analog signal into a digital signal and sending it to the controller; The controller is further configured to adjust the first PWM signal according to the digital signal so that the analog signal is the target value; wherein the controller is configured to output the adjustment signal and the execution signal after determining that the analog signal is normal, or to output an alarm signal when determining that the analog signal is abnormal.

8. The fan control system according to claim 1, characterized in that, Each of the plurality of fans is provided with a speed feedback element, which is used to feed back the speed signal of each fan to the controller; The controller is also configured to determine whether the fan speed is normal based on the speed signal, and to output an abnormal signal when there is an abnormality.

9. A fan control method, characterized in that, The method includes: The first PWM signal is output based on the temperature detection result; Convert the first PWM signal into an analog signal; Based on the preset voltage range corresponding to the analog signal, a target fan is determined among multiple fans; wherein different preset voltage ranges correspond to different fans.

10. A power electronic conversion device, characterized in that, The power electronic conversion device includes a fan control system and a heat-generating component as described in any one of claims 1-8. The fan control system includes a plurality of fans and is used to determine a target fan among the plurality of fans based on the temperature detection result of the heat-generating component. The target fan is used to dissipate heat from the heat-generating component.

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