Speed regulating device of fan and electronic measuring equipment

Abstract

The invention discloses a fan speed regulating device and electronic measuring equipment, and relates to the technical field of heat dissipation. The speed regulation device comprises a voltage conversion circuit, a control module and a voltage control circuit. The voltage conversion circuit comprises a power input end, a working voltage output end and a voltage feedback end and is used for being connected with an input power source through the power input end and outputting working voltage used for fan rotation through the working voltage output end after voltage conversion. The voltage conversion circuit is configured to adjust the output working voltage based on the feedback voltage input by the voltage feedback end. The control module is used for acquiring target rotating speed of the fan and determining second electrical parameters according to the target rotating speed. The voltage control circuit is used for receiving the second electrical parameter from the control module, adjusting the first electrical parameter of the voltage control circuit according to the second electrical parameter, and changing the feedback voltage of the input voltage feedback end according to the first electrical parameter so as to adjust the working voltage output by the voltage conversion circuit. Therefore, the speed regulation device capable of precisely regulating the speed of the fan is provided.

Description

Technical Field

[0001] The present application relates to the field of heat dissipation technology, and in particular to a fan speed regulating device and an electronic measuring device. Background Art

[0002] With the development of technology, the heat generated in electronic devices is getting higher and higher, especially in some small desktop devices. Heat dissipation is a major focus in the R&D and design stage, and cooling fans are indispensable. The fan's air volume, the heat dissipation effect of the device and the fan speed are positively correlated. From the perspective of noise, when the device is in a low power state, the cooling fan should be set at a low voltage and low speed. As the working mode changes and the power consumption increases, the fan speed will increase at a suitable curve.

[0003] In measuring electronic instruments, such as oscilloscopes, spectrum analyzers, vector network analyzers, etc., there are many high-precision circuits and high-speed circuits. Especially in high-speed RF circuits, RF devices have high power consumption and their performance is greatly affected by temperature. The impact of temperature on circuit performance cannot be ignored. In order to miniaturize these instruments, a suitable fan speed control and heat dissipation solution is particularly important.

[0004] The existing fan speed control scheme cannot accurately reach and stabilize at an exact target speed, and it is also difficult to achieve precise temperature control when the speed is fully controllable. In small high-speed measurement high-end instruments, there is an urgent need for a low-interference, high-efficiency, and high-precision fan intelligent speed control solution, which is also a prerequisite for achieving precise temperature control by adjusting the fan speed. Summary of the invention

[0005] The main technical problem to be solved by the present application is to provide a fan speed regulating device for controlling the fan speed with high precision and an electronic measuring device equipped with the speed regulating device.

[0006] According to the first aspect, an embodiment provides a speed regulating device for a fan, comprising:

[0007] A voltage conversion circuit, the voltage conversion circuit includes a power input terminal and a working voltage output terminal, and is used to connect an input power supply through the power input terminal, and output a working voltage for fan rotation through the working voltage output terminal after voltage conversion. The voltage conversion circuit also includes a voltage feedback terminal, and the voltage conversion circuit is configured to adjust the output working voltage based on a feedback voltage input to the voltage feedback terminal;

[0008] A control module, used to obtain a target speed of the fan and determine a second electrical parameter according to the target speed;

[0009] A voltage control circuit, the voltage control circuit is respectively connected to the working voltage output terminal and the voltage feedback terminal of the control module and the voltage conversion circuit, and is used to receive a second electrical parameter from the control module, adjust the first electrical parameter of the voltage control circuit according to the second electrical parameter, and change the feedback voltage of the input voltage feedback terminal according to the first electrical parameter, thereby adjusting the working voltage output by the voltage conversion circuit until the measured speed of the fan approaches the target speed.

[0010] In one embodiment, the operating voltage includes a coarse adjustment operating voltage, and the second electrical parameter includes a second coarse adjustment electrical parameter in a coarse adjustment stage;

[0011] The control module obtains a target speed, determines a coarse adjustment working voltage corresponding to the target speed according to the target speed, and determines a second coarse adjustment electrical parameter according to the coarse adjustment working voltage;

[0012] The voltage control circuit adjusts the first electrical parameter according to the second coarse adjustment electrical parameter, and the rotation speed of the fan at the working voltage determined by the first electrical parameter after adjustment by the second coarse adjustment electrical parameter is the coarse adjustment speed.

[0013] In one embodiment, a curve function of voltage and average speed is stored in the control module, the control module obtains the target speed, determines the coarse adjustment working voltage according to the curve function of voltage and average speed, and determines the second coarse adjustment electrical parameter according to the coarse adjustment working voltage;

[0014] Among them, the control module obtains the measured speeds corresponding to multiple fans of the same model under the same voltage, and calculates the average speeds of multiple fans at the same voltage; the control module performs nonlinear fitting on different voltages of the fans and the average speeds corresponding to each voltage to generate a curve function of voltage and average speed.

[0015] In one embodiment, the operating voltage further includes a fine-tuning operating voltage, and the second electrical parameter further includes a second fine-tuning electrical parameter in a fine-tuning stage;

[0016] The control module obtains the coarse speed, uses the target speed to correct the coarse speed to determine the fine working voltage, and determines the second fine electrical parameter according to the fine working voltage;

[0017] The control voltage adjusts the first electrical parameter according to the second fine-tuning electrical parameter, and the rotation speed of the fan at the working voltage determined by the first electrical parameter after adjustment by the second fine-tuning electrical parameter is the fine-tuning speed.

[0018] In one embodiment, the control module further stores a correction equation of the rotation speed and the voltage, the control module obtains the target rotation speed and the coarse adjustment rotation speed, determines the second fine adjustment working voltage according to the correction equation of the rotation speed and the voltage; determines the second fine adjustment electrical parameter according to the second fine adjustment working voltage;

[0019] Among them, the control module obtains the measured speeds corresponding to multiple fans of the same model at the same voltage, and calculates the average speeds of multiple fans at the same voltage; the control module performs linear fitting on different voltages of the fans and the average speeds corresponding to each voltage to determine the speed change value of the fans under unit voltage transformation; and determines the correction equation of speed and voltage according to the speed change value.

[0020] In one embodiment, the control module obtains the speed difference between the fine-tuning speed and the target speed. When the speed difference is within a set threshold range, the voltage control circuit adjusts the first electrical parameter according to a preset adjustment threshold until the measured speed of the fan reaches the target speed.

[0021] In one embodiment, the voltage control circuit includes a resistance branch and an adjustable branch connected in series between the working voltage output terminal of the voltage conversion circuit and the output terminal of the control module;

[0022] The connection node between the resistance branch and the adjustable branch is connected to the voltage feedback end of the voltage conversion circuit, and the adjustable branch adjusts its first electrical parameter according to the second electrical parameter to change the voltage of the connection node between the resistance branch and the adjustable branch, thereby changing the feedback voltage of the input voltage feedback end.

[0023] In one embodiment, the resistance branch includes a first resistor, a first end of the first resistor is connected to the voltage feedback end, and a second end of the first resistor is connected to the working voltage output end;

[0024] The adjustable branch includes a second resistor and a potentiometer module, and the first electrical parameter is a code word of the potentiometer module; the first end of the second resistor is connected to the voltage feedback end, and the second end of the second resistor is connected to the potentiometer module;

[0025] The potentiometer module is also connected to the output end of the control module, and the code word of the potentiometer module is adjusted according to the second electrical parameter output by the control module.

[0026] In one embodiment, the resistance branch includes a first resistor, a first end of the first resistor is connected to the voltage feedback end, and a second end of the first resistor is connected to the working voltage output end;

[0027] The adjustable branch includes a second resistor and a digital analog conversion module, and the first electrical parameter is a codeword of the digital analog conversion module; the first end of the second resistor is connected to the voltage feedback end, and the second end of the second resistor is connected to the digital analog conversion module;

[0028] The digital-to-analog conversion module is also connected to the output end of the control module, and adjusts the codeword of the digital-to-analog conversion module according to the second electrical parameter output by the control module.

[0029] In one embodiment, the speed regulating device of the fan further includes a temperature sensing module, and the temperature sensing module is used to detect the temperature of the temperature sensitive device;

[0030] The control module is electrically connected to the temperature sensing module, collects the measured temperature signal output by the temperature sensing module, and adjusts the target speed according to the difference between the measured temperature and the preset target temperature.

[0031] According to a second aspect, an electronic measuring device is provided in one embodiment, comprising:

[0032] A radio frequency circuit, wherein the radio frequency circuit obtains a radio frequency signal to amplify the radio frequency signal;

[0033] A fan, used to cool the radio frequency circuit;

[0034] The fan speed regulating device is a fan speed regulating device as in any one of the above embodiments, and is used to adjust the actually measured rotation speed of the fan.

[0035] According to the speed regulating device and electronic measuring device of the fan of the above embodiment, the speed regulating device includes a voltage conversion circuit, a control module and a voltage control circuit. The voltage conversion circuit outputs a working voltage for the fan to rotate, and adjusts the working voltage based on the output feedback voltage. The control module obtains the target speed of the fan and determines the second electrical parameter according to the target speed. The voltage control circuit adjusts its own first electrical parameter according to the second electrical parameter, thereby changing the feedback voltage according to the first electrical parameter to adjust the working voltage. The present application adjusts the fan by obtaining the target speed of the fan, so it is necessary to obtain the measured speed of the fan, so as to accurately control the speed of the fan. The adjustment of the first electrical parameter can compensate for the errors that may exist in the electrical system, avoiding the inaccuracy caused by manual adjustment. At the same time, the present application uses a voltage conversion circuit to determine the working voltage, without additional circuit interference, and uses a voltage control circuit to accurately adjust the working voltage, thereby ensuring that the speed of the fan is accurately adjustable and the adjustment efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a fan speed regulating device in an embodiment;

[0037] Figure 2 A schematic diagram of a curve of fan speed and voltage in an embodiment;

[0038] Figure 3 A schematic diagram of a fitting curve of the average value of the voltage and the rotation speed of a fan in one embodiment;

[0039] Figure 4 A schematic diagram of the structure of a voltage control circuit in an embodiment;

[0040] Figure 5 A schematic diagram of a circuit of a potentiometer module in an embodiment;

[0041] Figure 6 A flow chart of speed regulation in the coarse adjustment stage of a potentiometer module in one embodiment;

[0042] Figure 7 A flow chart of the speed regulation of a potentiometer module in one embodiment;

[0043] Figure 8 A flow chart of speed regulation in the fine adjustment stage of a potentiometer module in one embodiment;

[0044] Fig. 9 A circuit diagram of a digital-to-analog conversion module in an embodiment;

[0045] Fig.10 A flow chart of speed regulation in the coarse adjustment stage of a digital-to-analog conversion module in an embodiment;

[0046] Fig.11 A speed regulation flow chart of a digital-to-analog conversion module in an embodiment;

[0047] Fig.12 A speed regulation flow chart of a fine adjustment phase of a digital-to-analog conversion module in an embodiment;

[0048] Fig.13 A schematic diagram of the structure of fan fault detection in an embodiment;

[0049] Fig.14 A curve diagram of fan fault detection in an embodiment;

[0050] Fig.15 This is a schematic diagram of the structure of a temperature detection module in an embodiment;

[0051] Fig.16 FIG. 4 is a schematic diagram of the structure of an electronic measuring device in another embodiment. DETAILED DESCRIPTION

[0052] The present application is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0053] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0054] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0055] In one embodiment, the fan speed regulation scheme includes a voltage chopping method and a DC voltage regulation method.

[0056] The voltage chopping method chops the DC voltage into a high-speed pulse voltage to intermittently drive the fan coil. For example, a speed-adjustable fan with PWM speed control is directly used, or an additional electronic switch is connected in series with the fan power line, and then a high-speed PWM wave is used to control the switch to achieve speed regulation. The PWM frequency of this method is above 20KHz. Although this method is simple and efficient, the PWM pulse current on the power line will form very complex electromagnetic interference in the narrow space of the instrument. For measuring electronic instruments, especially spectrum analyzers, eliminating this interference is undoubtedly a challenge.

[0057] The DC voltage regulation method uses a linear power supply or a switching power supply to reduce the DC high voltage to a suitable low voltage for fan speed regulation, but the voltage control method is a major difficulty. Currently, there is a method of building a resistor network with resistors and MOS tubes to achieve several voltage outputs to control the fan speed. In this method, the speed step is often large, and high-precision speed regulation cannot be achieved. There is also a method of filtering PWM into DC and then controlling a linear or switching power supply. This method requires a special power conversion circuit, which is complex in design and has low control accuracy.

[0058] Based on the above shortcomings, please refer to Figure 1 The present application provides a fan speed regulating device 100 , which includes a voltage conversion circuit 110 , a control module 120 and a voltage control circuit 130 .

[0059] In one embodiment, the voltage conversion circuit 110 includes a power input terminal and a working voltage output terminal. The power input terminal of the voltage conversion circuit 110 is connected to the input power supply. The voltage inputted by the input power supply is converted into a working voltage through the working voltage output terminal, and the working voltage is used to drive the fan to rotate. The voltage conversion circuit 110 includes a voltage feedback terminal, which outputs a feedback voltage. The feedback voltage is adjusted using the configuration parameters of the voltage conversion circuit 110 to output the working voltage.

[0060] In one embodiment, the control module 120 is used to obtain a target speed of the fan and determine the second electrical parameter according to the target speed. After the control module 120 obtains the preset target speed of the fan, it adjusts the measured speed of the fan according to the target speed, obtains the measured speed of the fan after the adjustment, determines the difference from the target speed according to the measured speed, and continues to adjust the measured speed of the fan, wherein the measured speed of the fan is the speed actually measured in real time by the fan.

[0061] In one embodiment, the voltage control circuit 130 is respectively connected to the working voltage output terminal and the voltage feedback terminal of the control module 120 and the voltage conversion circuit 110. The voltage control circuit 130 receives the second electrical parameter from the control module 120, adjusts the first electrical parameter of the voltage control circuit 130 according to the second electrical parameter, and changes the feedback voltage input to the voltage feedback terminal in the voltage conversion circuit 110 according to the first electrical parameter, thereby adjusting the working voltage outputted by the working voltage output terminal in the voltage conversion circuit 110.

[0062] It should be noted that the voltage conversion circuit 110 adopts a DC-DC conversion circuit, and the input power is converted by the DC-DC conversion circuit, so that the working voltage for driving the fan to rotate is generated at the working electrical output end of the DC-DC conversion circuit, and the magnitude of the working voltage can be adjusted by the first electrical parameter of the voltage control circuit 130 through the second electrical parameter determined by the control module 120, so as to adjust the actual measured speed of the fan. Among them, the DC-DC conversion circuit can use a common BUCK or BOOST circuit, and the voltage control circuit 130 is introduced into the DC-DC conversion circuit, so as to achieve precise control of the working voltage.

[0063] In one embodiment, the adjustment of the working voltage includes three stages: a coarse adjustment stage, a fine adjustment stage and a cyclic fine adjustment stage, wherein the speed error corresponding to the coarse adjustment stage is greater than the speed error corresponding to the fine adjustment stage, and the speed error corresponding to the fine adjustment stage is greater than the speed error corresponding to the cyclic fine adjustment stage. In a specific embodiment, the coarse adjustment stage, the fine adjustment stage and the cyclic fine adjustment stage can be divided according to preset time. For example, the coarse adjustment stage is entered for coarse adjustment for 5 seconds, the fine adjustment stage is entered for fine adjustment for 10 seconds, and the cyclic fine adjustment stage is entered for fine adjustment for 20 seconds, wherein the specific preset time is manually preset according to actual conditions. In addition, the coarse adjustment stage, the fine adjustment stage and the cyclic fine adjustment stage can also be divided according to whether the detected measured speed reaches a preset speed range. For example, when the detected measured speed reaches a first preset speed range, the coarse adjustment stage is entered for coarse adjustment. When the detected measured speed reaches a second preset speed range, the fine adjustment stage is entered for fine adjustment. When the detected measured speed reaches a second preset speed range, the fine adjustment stage is entered for fine adjustment. When the measured speed reaches the third preset speed range, it enters the cyclic fine-tuning stage for fine-tuning, wherein the first preset speed range is greater than the second preset speed range, and the second preset speed range is greater than the third preset speed range; furthermore, the coarse adjustment stage, the fine adjustment stage and the cyclic fine-tuning stage can also be divided according to the estimated number of step values ​​required. For example, when the estimated step value detected reaches the first preset step value range, it enters the coarse adjustment stage for coarse adjustment. When the estimated step value detected reaches the second preset step value range, it enters the fine adjustment stage for fine adjustment. When the estimated step value detected reaches the third preset step value range, it enters the cyclic fine-tuning stage for fine adjustment, wherein the first preset step value range is greater than the second preset step value range, and the second preset step value range is greater than the third preset step value range. Of course, there can be many other ways to divide it, which can be adjusted according to actual conditions. I will not go into details here. The adjustment method and detailed content of each adjustment stage are specifically explained below.

[0064] In one embodiment, coarse adjustment refers to an initial adjustment of the measured speed of the fan according to the target speed of the fan. In the coarse adjustment stage, the control module 120 determines the working voltage corresponding to the target speed as the coarse adjustment working voltage based on the acquired target speed. The coarse adjustment working voltage is calculated based on the target speed. The control module 120 calculates the second coarse adjustment electrical parameter currently required based on the required coarse adjustment working voltage. The voltage control circuit 130 adjusts the first electrical parameter according to the second coarse adjustment electrical parameter. Since the first electrical parameter has been adjusted in the voltage control circuit 130, the working voltage output based on the feedback voltage has been changed. At this time, the rotation speed of the fan under the changed working voltage is the coarse adjustment speed.

[0065] In one embodiment, even for fans of the same model, the correspondence between the measured speed and voltage is not exactly the same. Therefore, by measuring the measured speeds corresponding to multiple fans of the same model at the same voltage, the consistency of the measured speeds of the fans of this model can be evaluated, and a polynomial can be fitted to establish a curve function of voltage and average speed.

[0066] In one embodiment, please refer to Figure 2 The schematic diagram of the curve of the measured speed and voltage of the fan is shown in the figure. The curves of the measured speed and voltage of the 6 fans in the figure have a large degree of discreteness and are not completely linear, and cannot be directly used to correct the measured speed. Therefore, in the control module 120 of the present application, the measured speeds corresponding to multiple fans of the same model at the same voltage are obtained respectively, and the average speeds of the multiple fans at the same voltage are calculated respectively. The control module 120 performs nonlinear fitting on the different voltages of the fan and the average speeds corresponding to each voltage, so as to determine the curve function of the voltage and the average speed. After obtaining the target speed, the control module 120 calculates the coarse adjustment working voltage corresponding to the target speed through the curve function of the voltage and the average speed, and thereby determines the second coarse adjustment electrical parameter according to the coarse adjustment working voltage.

[0067] Please refer to Figure 3 In one embodiment, the control module 120 uses a third-order polynomial to perform nonlinear fitting on different voltages of the fan and the average speeds corresponding to each voltage, so that the curve function of the voltage and the average speed is obtained as follows:

[0068] y=1.151e-11x 3 -1.734e -07 x 2 +2.024e -03 x-1.706e

[0069] Among them, y represents the voltage and x represents the average speed of the fan.

[0070] In one embodiment, after the fan is adjusted in the coarse adjustment stage, there may still be a certain gap between the fan's current coarse adjustment speed and the target speed, so the fan needs to be fine-tuned after the coarse adjustment is completed.

[0071] In one embodiment, fine adjustment refers to re-adjusting the measured speed of the fan according to the target speed of the fan on the basis of coarse adjustment. In the fine adjustment stage, the control module 120 corrects the coarse adjustment speed according to the acquired target speed, thereby determining the fine adjustment working voltage. The control module 120 calculates the second fine adjustment electrical parameter currently required based on the fine adjustment working voltage. The voltage control circuit 130 adjusts the first electrical parameter according to the second fine adjustment electrical parameter. Since the first electrical parameter has been adjusted in the voltage control circuit 130, the working voltage output based on the feedback voltage is also changed. At this time, the speed of the fan under the changed working voltage is the fine adjustment speed.

[0072] Please refer to Figure 3 In one embodiment, the control module 120 also uses a first-order polynomial to perform linear fitting on different voltages of the fan and the average speed values ​​corresponding to each voltage, thereby obtaining a first-order function:

[0073] y=1.361e -03 x-1.439e

[0074] Among them, y represents the voltage and x represents the average speed of the fan.

[0075] In one embodiment, after determining the first-order function, the speed change value of the fan under unit voltage transformation can be determined. That is, according to the first-order function, when the voltage changes by 1V, the speed changes by about 1 / 1.361e -03 =734.75 rpm, the control module 120 determines the correction equation of the speed and voltage according to the speed change value:

[0076]

[0077] Among them, V 修改 Indicates fine-tuning the operating voltage, V 当前 Indicates the coarse adjustment working voltage, F 修改 Indicates the target speed, F 当前 Indicates coarse speed adjustment.

[0078] In one embodiment, after the fan is fine-tuned, the fan's current fine-tuning speed and the target speed are already very close, so in order to improve the adjustment efficiency of the measured speed, a cyclic fine-tuning stage is entered, wherein the cyclic fine-tuning refers to fine-tuning the first electrical parameter according to the result of the fine-tuning, so that the measured speed of the fan accurately and gradually approaches the target speed. The control module 120 obtains the speed difference between the fine-tuning speed and the target speed. If the speed difference is within the set threshold range, the voltage control circuit 130 adjusts the first electrical parameter in response to the adjustment threshold sent by the control module 120 until the measured speed of the fan approaches the target speed. Here, the measured speed of the fan approaching the target speed can be the measured speed of the fan reaching the preset threshold range corresponding to the target speed, and the preset threshold range corresponding to the target speed can be artificially determined according to actual conditions.

[0079] In one embodiment, the fan rotates under the drive of the working voltage, the control module 120 determines the second electrical parameter required for the fan to reach the target speed according to the target speed, and the voltage control circuit 130 changes the feedback voltage using the second electrical parameter, thereby adjusting the working voltage so that the measured speed of the fan reaches the target speed. Then, in the voltage control circuit 130, the purpose is essentially to change the resistance or voltage of the entire voltage control circuit 130, so that the working voltage output by the voltage conversion circuit 110 based on the feedback voltage is changed.

[0080] Please refer to Figure 4 In one embodiment, the voltage control circuit 130 includes a resistor branch 131 and an adjustable branch 132 connected in series between the working voltage output terminal of the voltage conversion circuit 110 and the output terminal of the control module 120. The connection node of the resistor branch 131 and the adjustable branch 132 is connected to the voltage feedback terminal of the voltage conversion circuit 110, and the adjustable branch 132 changes its first electrical parameter according to the second electrical parameter determined by the control module 120, thereby changing the voltage of the connection node between the resistor branch 131 and the adjustable branch 132 to change the feedback voltage of the input voltage feedback terminal.

[0081] In one embodiment, to ensure that the fan can work normally, the control module 120 is connected to the enable end of the DC-DC conversion circuit so that the DC-DC conversion circuit can work normally, and the enable end of the DC-DC conversion circuit is also connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the input power supply.

[0082] Please refer to Figure 5In one embodiment, the resistor branch 131 includes a first resistor R1, and the adjustable branch 132 includes a second resistor R2 and a potentiometer module RX, then the first electrical parameter is the codeword of the potentiometer module. The first end of the first resistor R1 is connected to the voltage feedback end, and the second end of the first resistor R1 is connected to the working voltage output end. The first end of the second resistor R2 is connected to the voltage feedback end, and the second end of the second resistor R2 is connected to the potentiometer module RX, and the potentiometer module RX is also connected to the output end of the control module 120.

[0083] Please refer to Figure 6 and Figure 7 In one embodiment, in the coarse adjustment stage, the control module 120 calculates the coarse adjustment working voltage required for the fan to reach the target speed according to the target speed, that is, calculates the coarse adjustment working voltage according to the curve function of the voltage and the average speed, and calculates the second coarse adjustment electrical parameter according to the coarse adjustment working voltage, that is, calculates the code word required by the potentiometer module RX to reach the coarse adjustment working voltage according to the coarse adjustment working voltage, and adjusts the code word of the potentiometer module RX according to the calculated code word required by the potentiometer module RX.

[0084] In one embodiment, the following formula is used to calculate the codeword required by the potentiometer module RX to achieve the coarse adjustment working voltage:

[0085]

[0086] Among them, V OUT Indicates the coarse adjustment working voltage, V FB Represents the feedback voltage, R R1 Represents the resistance value of the first resistor R1, R R2 represents the resistance value of the second resistor R2, and N represents the code word of the potentiometer module RX.

[0087] It should be noted that the feedback voltage does not change when it is output through the voltage conversion circuit 110 before adjustment, but since the total resistance of the resistance branch changes, the voltage of the connection node between the resistance branch and the adjustable branch changes, and the connection node is connected to the voltage feedback terminal, which is equivalent to changing the output feedback voltage. When calculating the code word of the potentiometer module RX, the voltage value of the feedback voltage is the voltage value output by the voltage value conversion circuit 110.

[0088] In one embodiment, after calculating the codeword of the potentiometer module RX, the voltage control circuit 130 adjusts the feedback voltage of the potentiometer module RX according to the calculated codeword of the potentiometer module RX, so the working voltage also changes accordingly, and the speed of the fan under the changed working voltage is the coarse adjustment speed.

[0089] It should be noted that the potentiometer module RX is a device that can adjust the resistance value by digital control, including a resistor network and a control circuit (such as SPI or I 2 C controller). The resistor network is composed of many tiny resistors, which are connected by switches to form different resistance values. The control circuit uses the digital code word N to select a certain gradation of the resistor network according to the input digital code word N, thereby adjusting the total resistance value. Among them, N is a register used to control the resistance value, and the commonly used bit width is 8 bits. This application does not limit the specific bit width of the potentiometer module RX, and only 8 bits are used as an example for illustration.

[0090] If the potentiometer module RX is 8 bits, then the value range of N is 0-255. The resistance adjustment of the potentiometer module RX is discrete. Each code word N corresponds to a fixed resistance value. The resistance difference between two adjacent N values ​​is called the step difference. Then the step value of the 8-bit potentiometer module RX is:

[0091]

[0092] Among them, ΔR represents the step value of the potentiometer module RX, R total Indicates the total resistance of the potentiometer module RX.

[0093] The step accuracy is the percentage of the step value relative to the total resistance value:

[0094]

[0095] Therefore, in the 8-bit potentiometer module RX, each step (N increases or decreases by 1) adjusts the resistance value by about 0.39% of the total resistance value, so the operating voltage can be changed immediately. If a more precise change of the operating voltage is required, a higher-bit potentiometer module RX can be used.

[0096] Please refer to Figure 7 and Figure 8In one embodiment, when entering the fine adjustment stage, the control module 120 obtains the coarse adjustment speed, corrects the coarse adjustment speed according to the target speed, and thus determines the fine adjustment working voltage, that is, the fine adjustment working voltage is determined according to the correction equation of the speed and voltage. The second fine adjustment electrical parameter is calculated according to the fine adjustment working voltage, that is, the same formula as in the coarse adjustment stage is used to calculate the code word required by the potentiometer module RX to achieve the fine adjustment working voltage according to the fine adjustment working voltage, and the code word of the potentiometer module RX is adjusted according to the calculated code word required by the potentiometer module RX. After calculating the code word of the potentiometer module RX, the voltage control circuit 130 adjusts the code word of the potentiometer module RX according to the calculated code word of the potentiometer module RX, so that the working voltage generated based on the feedback voltage will also change accordingly, and the speed of the fan under the changed working voltage is obtained as the fine adjustment speed.

[0097] Please refer to Figure 7 In one embodiment, after the coarse adjustment stage and the fine adjustment stage, the fine adjustment speed is very close to the target speed, with only a few step value errors. Therefore, the cyclic fine adjustment state is entered, and the fan speed is monitored every 1s. If the current fine adjustment speed is greater than or less than the target speed, the code word N of the potentiometer module RX is increased or decreased by 1.

[0098] Please refer to Fig. 9 In one embodiment, in order to obtain higher adjustment accuracy, the resistance branch 131 includes a first resistor R1, and the adjustable branch 132 includes a second resistor R2 and a digital-to-analog conversion module, then the first electrical parameter is the codeword of the digital-to-analog conversion module. The first end of the first resistor R1 is connected to the voltage feedback end, and the second end of the first resistor R1 is connected to the working voltage output end. The first end of the second resistor R2 is connected to the voltage feedback end, and the second end of the second resistor R2 is connected to the digital-to-analog conversion module, and the digital-to-analog conversion module is also connected to the output end of the control module 120.

[0099] Please refer to Fig.10 and Fig.11 In one embodiment, in the coarse adjustment stage, the control module 120 calculates the coarse adjustment working voltage required for the fan to reach the target speed according to the target speed, that is, calculates the working voltage according to the curve function of the voltage and the average speed, and calculates the second coarse adjustment electrical parameter according to the coarse adjustment working voltage, that is, calculates the code word required by the digital-to-analog conversion module to reach the coarse adjustment working voltage according to the coarse adjustment working voltage, and adjusts the code word of the digital-to-analog conversion module according to the calculated code word required by the digital-to-analog conversion module.

[0100] In one embodiment, the following formula is used to calculate the codeword required by the digital-to-analog conversion module to achieve the coarse adjustment working voltage:

[0101]

[0102] Among them, V OUT Indicates the coarse adjustment working voltage, V FB Represents the feedback voltage, V ref Represents the reference voltage of the digital-to-analog conversion module, R R1 Represents the resistance value of the first resistor R1, R R2 represents the resistance value of the second resistor R2, and N represents the code word of the digital-to-analog conversion module.

[0103] It should be noted that when the adjustment step accuracy of the potentiometer module RX may not meet some application scenarios that require higher accuracy, the present application can improve the adjustment accuracy by replacing the potentiometer module RX with a voltage output circuit controlled by a digital-to-analog conversion module. The digital-to-analog conversion module converts the digital signal N into an analog voltage signal Vdac, where N is the digital input value of the digital-to-analog conversion module, usually a binary codeword. The present application does not limit the specific number of bits of the digital-to-analog conversion module, but only takes 12 bits as an example, so the maximum value of N is 2 12 -1=4095, then the input in the formula for calculating the codeword required by the digital-to-analog conversion module is 4095. If other bit numbers are used, the corresponding maximum value of N is input. In this 12-bit digital-to-analog conversion module, each time the value of N is increased or decreased, the change step of the voltage Vdac output by the digital-to-analog conversion module is:

[0104]

[0105] Wherein, ΔV represents the step value of the voltage Vdac output by the digital-to-analog conversion module, V ref Indicates the reference voltage of the digital-to-analog conversion module.

[0106] The step accuracy is the percentage of the step value relative to the reference voltage:

[0107]

[0108] Therefore, the 12-bit digital-to-analog conversion module has a higher bit width, a smaller step value, and a higher precision than the 8-bit potentiometer module RX. By replacing the potentiometer module RX with the digital-to-analog conversion module, more delicate adjustments can be achieved within a smaller voltage range.

[0109] In one embodiment, after calculating the codeword of the digital-to-analog conversion module, the voltage control circuit 130 adjusts the codeword of the digital-to-analog conversion module according to the calculated codeword of the digital-to-analog conversion module, so that the working voltage generated based on the feedback voltage also changes accordingly, and the speed of the fan under the changed working voltage is obtained as the coarse adjustment speed.

[0110] Please refer to Fig.11 and Fig.12 In one embodiment, when entering the fine-tuning stage, the control module 120 obtains the coarse-tuning speed, corrects the coarse-tuning speed according to the target speed, and thereby determines the fine-tuning working voltage, that is, the fine-tuning working voltage is determined according to the correction equation of the speed and voltage. The second fine-tuning electrical parameter is calculated according to the fine-tuning working voltage, that is, the codeword required by the digital-to-analog conversion module to achieve the fine-tuning working voltage is calculated according to the fine-tuning working voltage using the same formula as in the coarse-tuning stage, and the codeword of the digital-to-analog conversion module is adjusted according to the calculated codeword required by the digital-to-analog conversion module. After calculating the codeword of the digital-to-analog conversion module, the voltage control circuit 130 adjusts the codeword of the digital-to-analog conversion module according to the calculated codeword of the digital-to-analog conversion module, and then the working voltage generated based on the feedback voltage also changes accordingly, and the speed of the fan obtained under the changed working voltage is the fine-tuning speed.

[0111] Please refer to Fig.11 In one embodiment, after the coarse adjustment stage and the fine adjustment stage, the fine adjustment speed is very close to the target speed, with only a few step value errors. Therefore, the cyclic fine adjustment state is entered, and the fan measured speed is monitored every 1s. To speed up the adjustment speed of the cyclic fine adjustment, if the current fine adjustment speed is greater than or less than the target speed, the code word N of the potentiometer module RX is added or subtracted by X, where X is greater than or equal to 2, and the larger the X, the faster the speed.

[0112] Please refer to Fig.13 In one embodiment, in the fan speed regulating device 100 provided in the present application, the control module 120 uses the CPU and FPGA to run in parallel, and can measure the actual speed of the fan at a very fast speed, and can measure the actual speed of the fan every several milliseconds. Then, the fault of the fan can be detected according to the ratio of the actual speed of the fan to the average speed.

[0113] Please refer to Fig.14 In one embodiment, a normal line is set at 0.8-1.2 times according to the ratio of the fan's measured speed to the average speed. The speed within the normal line is normal; an underspeed line is set at 0.6 times to warn the fan of serious dust accumulation, oil accumulation or aging; a stall line is set at 0.2 times to deal with foreign body stalling. Once the measured speed crosses the underspeed line from the normal line and pierces the stall line, the device will quickly save the configuration, flash the light and shut down. All these abnormal monitoring are implemented by FPGA, and the response delay is less than 10ms.

[0114] Please refer to Fig.15In one embodiment, the target speed can also be determined according to a preset target temperature. In this case, a temperature sensing module 140 is provided in the fan speed regulation device 100. The temperature sensing module 140 is used to detect the temperature of the temperature sensitive device. The control module 120 is electrically connected to the temperature sensing module 140 to collect the measured temperature signal output by the temperature sensing module 140, and adjust the target speed according to the difference between the measured temperature and the preset target temperature.

[0115] In one embodiment, the CPU in the control module 120 monitors the current temperature value of the temperature sensing module 140, inputs it into the temperature control PID algorithm module, calculates the actual speed that should be configured at the current temperature, and then adjusts the actual speed to the target speed through the coarse adjustment stage and the fine adjustment stage. The debugged PID algorithm will adjust the temperature to the target temperature at an appropriate adjustment speed to achieve temperature closed-loop control.

[0116] The fan speed regulating device 100 provided in the present application uses a voltage conversion circuit 110 to achieve precise control of the working voltage, and uses a curve function of voltage and average speed to accurately determine the working voltage required for the target speed, and then uses three stages of coarse adjustment stage, fine adjustment stage and cyclic adjustment to accurately adjust the measured speed of the fan. In addition, the present application provides temperature control, which can achieve high-precision temperature control and provide a nearly constant temperature environment for temperature-sensitive devices.

[0117] Please refer to Fig.16 In another embodiment, the present application further provides an electronic measuring device 1, which includes a radio frequency circuit 11, a fan 12 and a speed regulating device 100 of the fan.

[0118] In one embodiment, the RF circuit 11 obtains the RF signal to amplify the RF signal. The fan 12 is used to cool the RF circuit 11. The fan speed regulating device 100 adopts the fan speed regulating device 100 in any of the above embodiments, which is used to adjust the measured speed of the fan 12. Since the fan speed regulating device 100 has been clearly explained in the above embodiments, it will not be repeated here.

[0119] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0120] The above specific examples are used to illustrate the present application, which is only used to help understand the present application and is not intended to limit the present application. For technicians in the technical field to which the present application belongs, they can also make some simple deductions, deformations or substitutions based on the ideas of the present application.

Claims

1. A fan speed regulating device, characterized in that: include: A voltage conversion circuit, the voltage conversion circuit comprising a power input terminal and a working voltage output terminal, for connecting an input power supply through the power input terminal, and outputting a working voltage for fan rotation through the working voltage output terminal after voltage conversion, the voltage conversion circuit further comprising a voltage feedback terminal, the voltage conversion circuit being configured to adjust the output working voltage based on a feedback voltage input to the voltage feedback terminal; A control module, configured to obtain a target speed of the fan and determine a second electrical parameter according to the target speed; A voltage control circuit, wherein the voltage control circuit is respectively connected to the working voltage output terminal and the voltage feedback terminal of the control module and the voltage conversion circuit, and is used to receive a second electrical parameter from the control module, adjust a first electrical parameter of the voltage control circuit according to the second electrical parameter, and change a feedback voltage input to the voltage feedback terminal according to the first electrical parameter, thereby adjusting the working voltage output by the voltage conversion circuit until the measured speed of the fan approaches the target speed.

2. The fan speed regulating device according to claim 1, characterized in that: The operating voltage includes a coarse adjustment operating voltage, and the second electrical parameter includes a second coarse adjustment electrical parameter in a coarse adjustment stage; The control module acquires the target speed, determines the coarse adjustment working voltage corresponding to the target speed according to the target speed, and determines the second coarse adjustment electrical parameter according to the coarse adjustment working voltage; The voltage control circuit adjusts the first electrical parameter according to the second coarse adjustment electrical parameter, and the rotation speed of the fan at the working voltage determined by the first electrical parameter after adjustment by the second coarse adjustment electrical parameter is the coarse adjustment speed.

3. The fan speed regulating device according to claim 2, characterized in that: The control module stores a curve function of voltage and average speed, and the control module obtains the target speed, determines the coarse adjustment working voltage according to the curve function of voltage and average speed, and determines the second coarse adjustment electrical parameter according to the coarse adjustment working voltage; Among them, the control module obtains the measured speeds corresponding to multiple fans of the same model under the same voltage, and calculates the average speeds of multiple fans at the same voltage; the control module performs nonlinear fitting on different voltages of the fans and the average speeds corresponding to each voltage to generate a curve function of voltage and average speed.

4. The fan speed regulating device according to claim 2, characterized in that: The working voltage also includes a fine-tuning working voltage, and the second electrical parameter also includes a second fine-tuning electrical parameter in a fine-tuning stage; The control module obtains the coarse speed, uses the target speed to correct the coarse speed to determine the fine working voltage, and determines the second fine electrical parameter according to the fine working voltage; The control voltage adjusts the first electrical parameter according to the second fine-tuning electrical parameter, and the rotation speed of the fan at the working voltage determined by the first electrical parameter after adjustment by the second fine-tuning electrical parameter is the fine-tuning speed.

5. The fan speed regulating device according to claim 4, characterized in that: The control module also stores a correction equation of the rotation speed and the voltage. The control module obtains the target rotation speed and the coarse adjustment rotation speed, and determines the second fine adjustment working voltage according to the correction equation of the rotation speed and the voltage. determining the second fine adjustment electrical parameter according to the second fine adjustment working voltage; Among them, the control module respectively obtains the measured speeds corresponding to multiple fans of the same model at the same voltage, and respectively calculates the average speeds of multiple fans at the same voltage; the control module performs linear fitting on different voltages of the fans and the average speeds corresponding to each voltage to determine the speed change value of the fans under unit voltage transformation; and determines the correction equation of the speed and voltage according to the speed change value.

6. The fan speed regulating device according to claim 4, characterized in that: The control module obtains the speed difference between the fine-tuning speed and the target speed. When the speed difference is within a set threshold range, the voltage control circuit adjusts the first electrical parameter according to a preset adjustment threshold until the measured speed of the fan approaches the target speed.

7. The fan speed regulating device according to any one of claims 1 to 6, characterized in that: The voltage control circuit comprises a resistance branch and an adjustable branch connected in series between the working voltage output end of the voltage conversion circuit and the output end of the control module; The connection node of the resistance branch and the adjustable branch is connected to the voltage feedback terminal of the voltage conversion circuit, and the adjustable branch adjusts its first electrical parameter according to the second electrical parameter to change the voltage of the connection node of the resistance branch and the adjustable branch, thereby changing the feedback voltage input to the voltage feedback terminal.

8. The fan speed regulating device according to claim 7, characterized in that: The resistance branch comprises a first resistor, a first end of the first resistor is connected to the voltage feedback end, and a second end of the first resistor is connected to the working voltage output end; The adjustable branch includes a second resistor and a potentiometer module, the first electrical parameter is a code word of the potentiometer module; the first end of the second resistor is connected to the voltage feedback end, and the second end of the second resistor is connected to the potentiometer module; The potentiometer module is also connected to the output end of the control module, and the code word of the potentiometer module is adjusted according to the second electrical parameter output by the control module.

9. The fan speed regulating device according to claim 8, characterized in that: The resistance branch comprises a first resistor, a first end of the first resistor is connected to the voltage feedback end, and a second end of the first resistor is connected to the working voltage output end; The adjustable branch includes a second resistor and a digital-to-analog conversion module, the first electrical parameter is a codeword of the digital-to-analog conversion module; a first end of the second resistor is connected to the voltage feedback end, and a second end of the second resistor is connected to the digital-to-analog conversion module; The digital-to-analog conversion module is also connected to the output end of the control module, and adjusts the codeword of the digital-to-analog conversion module according to the second electrical parameter output by the control module.

10. The fan speed regulating device according to claim 9, characterized in that: The fan speed regulating device further comprises a temperature sensing module, and the temperature sensing module is used to detect the temperature of the temperature sensitive device; The control module is electrically connected to the temperature sensing module, collects the measured temperature signal output by the temperature sensing module, and adjusts the target speed according to the difference between the measured temperature and the preset target temperature.

11. An electronic measuring device, characterized in that: include: A radio frequency circuit, wherein the radio frequency circuit acquires a radio frequency signal to amplify the radio frequency signal; A fan, used to cool the radio frequency circuit; A fan speed regulating device, wherein the fan speed regulating device adopts the fan speed regulating device as described in any one of claims 1 to 10, and is used to adjust the actually measured rotation speed of the fan.

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