Temperature and rotating speed double-closed-loop control device and method for rotary Stirling cryocooler

Abstract

The invention discloses a temperature and rotating speed double-closed-loop control device and method for a rotary Stirling cryocooler. The temperature and rotating speed double-closed-loop control device comprises a temperature acquisition module, a rotating speed acquisition module, a DSP closed-loop control module, a six-path control signal DSP output module, a driving module and a three-phase power bridge module. The output of the temperature acquisition module and the output of the DSP rotating speed acquisition module are connected to the input of the DSP closed-loop control module, the output of the DSP closed-loop control module is connected to the input of the six-way control signal DSP output module, and the output of the six-way control signal DSP output module is connected to the input of the driving module. And the output of the driving module is connected to the input of the three-phase power bridge module. According to the temperature and rotating speed double-closed-loop control device and method for the rotary Stirling cryocooler, temperature and rotating speed double-closed-loop control is achieved through the digital DSP, the control precision and stability of the rotary Stirling cryocooler are improved, and the service life of the rotary Stirling cryocooler can be prolonged.

Description

Technical Field

[0001] This invention belongs to the field of Stirling refrigerator control technology, and relates to a dual closed-loop control device and method for temperature and speed of a rotary Stirling refrigerator. Background Technology

[0002] The rotary Stirling refrigerator is an electrically driven mechanical refrigerator that achieves cooling through the periodic expansion and compression of an internal gaseous working fluid. Due to its compact design, light weight, and high efficiency, it is the preferred type of miniature refrigerator for tactical applications.

[0003] With the widespread application of infrared detectors in various fields, infrared detectors, as passive, temperature-sensitive semiconductor imaging devices, typically require stable low-temperature environments to achieve optimal infrared imaging results. To provide the stable low-temperature environment required by infrared detectors, rotary Stirling refrigerators, with precise temperature control via drive circuit controllers, are one of the primary cooling media. Currently, the control systems of rotary Stirling refrigerators mainly employ traditional unipolar or bipolar SPWM control methods with intermittent H-bridge control and complementary H-bridge control, forming closed loops or protection mechanisms by detecting the hot and cold end temperatures and the vibration of the machine body. While this control method can basically control the Stirling refrigerator, it suffers from insufficient temperature control accuracy and poor control stability, making it difficult to meet high-precision control requirements. Furthermore, existing control systems cannot ensure optimal efficiency across the entire operating range, exhibiting limitations in fixed-frequency and phase voltage frequency control, hindering high-efficiency operation and maintaining optimal operating conditions. Therefore, there is an urgent need for a dual closed-loop control device and method for temperature and speed of rotary Stirling refrigerators that can improve temperature control accuracy, enhance control stability, and achieve high-efficiency operation. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of this invention is to provide a dual closed-loop control device and method for temperature and speed of a rotary Stirling refrigerator, which improves the temperature control accuracy and the stability of operation, and has the characteristics of simple structure and low cost.

[0005] This invention is achieved through the following technical solution: A rotary Stirling refrigerator with dual closed-loop control for temperature and speed, comprising: Temperature acquisition module, used to acquire real-time temperature signals from rotary Stirling refrigerator; The speed acquisition module is used to acquire the real-time speed signal of the rotary Stirling refrigerator; The DSP closed-loop control module is used to perform dual closed-loop control calculations based on the acquired temperature and speed signals. A 6-channel control signal DSP output module is used to generate 6 voltage signals; The driving module is used to drive and amplify the six voltage signals. The three-phase power bridge module is used to control the operation of the rotary Stirling refrigerator motor based on the six voltage signals after driving, so as to achieve speed and temperature regulation; The outputs of the temperature acquisition module and the speed acquisition module are both connected to the input of the DSP closed-loop control module. The output of the DSP closed-loop control module is connected to the input of the 6-channel control signal DSP output module. The output of the 6-channel control signal DSP output module is connected to the input of the drive module. The output of the drive module is connected to the input of the three-phase power bridge module.

[0006] Preferably, the temperature acquisition module includes a signal conditioning circuit, an AD conversion circuit, and an SPI transmission circuit; The temperature signal is used as the input to the signal conditioning circuit, the output of which is connected to the input of the AD conversion circuit, and the output of the AD conversion circuit is connected to the input of the DSP closed-loop control module through the SPI transmission circuit.

[0007] Preferably, the speed acquisition module includes a DSP capture interrupt unit, a speed calculation unit, and a filtering unit; the filtering unit includes an average value filter and a low-pass filter; The Hall position signal of the rotary Stirling refrigerator is used as the input of the DSP capture interrupt unit. The trigger time difference ΔT between two consecutive capture interrupts of the same phase Hall position signal is recorded. The trigger time difference ΔT is used as the input of the speed calculation unit, and the output of the speed calculation unit is n'. The specific calculation process is as follows:

[0008] Where p is the number of pole pairs of the rotating Stirling refrigerator; Output of the speed calculation unit As the input to the averaging filter, the output of the averaging filter is n(t), and the specific calculation process is as follows:

[0009] The speed calculation output n(t) of the average value filter is used as the input of the low-pass filter, and the output n of the low-pass filter is used as the output of the overall speed acquisition module. The specific calculation process is as follows:

[0010] in, The output speed of the average value filter at the current moment. α represents the rotational speed output of the average value filter at the previous moment, and α is the filter coefficient of the first-order linear low-pass filter.

[0011] Preferably, the DSP closed-loop control module includes: A temperature closed-loop control unit is used for segmented proportional-integral (PI) control based on temperature deviation. The speed closed-loop control unit is used to perform proportional-integral-derivative (PID) control based on the speed deviation and outputs the PWM duty cycle d. The output of the temperature acquisition module is connected to the input of the temperature closed-loop control unit. The output of the temperature closed-loop control unit and the output of the speed acquisition module serve as the input of the speed closed-loop control unit, and the output of the speed closed-loop control unit serves as the output of the DSP closed-loop control module.

[0012] Preferably, the temperature closed-loop control unit includes: The temperature difference calculation unit is used to calculate the temperature difference T between the set temperature and the actual temperature. up ; The segmented PI controller operates based on the temperature difference T. up PI control is performed, outputting a speed reference value. The control parameters of the segmented PI controller include the proportional control parameter Kp and the integral control parameter Ki. Kp and Ki vary with the temperature difference T. up The changes are adaptively adjusted online, and the specific adjustment formula is as follows: First segment: |T up |≥X Second segment: |T up |≤X Among them, Kp max This represents the initial maximum value of the proportional control parameter. X represents the minimum value of the integral control parameter in the second segment, X represents the segment interval, and y represents the rate of change of the integral control parameter in the second segment.

[0013] Preferably, the inputs of the speed closed-loop control unit include: The speed reference value output by the temperature closed-loop control unit; The actual rotational speed value output by the rotational speed acquisition module; The speed closed-loop control unit uses a PID control algorithm to output the PWM duty cycle d for adjusting the motor speed of the rotary Stirling refrigerator, which is then used as the output of the DSP closed-loop control module.

[0014] Preferably, the inputs of the 6-channel control signal DSP output module include: The output PWM duty cycle d of the DSP closed-loop control module and the three-phase Hall position signal of the rotary Stirling refrigerator; The 6-channel control signal DSP output module outputs 6 voltage signals based on two input signals.

[0015] Preferably, the input of the drive module is connected to the output of the 6-channel control signal DSP output module, and the output of the drive module provides 6 voltage signals that meet the turn-on and turn-off requirements of the three-phase power bridge module.

[0016] Preferably, the three-phase power bridge module consists of 6 VDMOS transistors, which receive 6 voltage signals output by the drive module to realize dual closed-loop control of the speed and temperature of the rotary Stirling refrigerator motor.

[0017] A method for dual closed-loop control of temperature and speed in a rotary Stirling refrigerator includes the following steps: The real-time temperature of the rotary Stirling refrigerator is obtained through a temperature acquisition module; The real-time rotational speed of the rotary Stirling refrigerator is obtained through the rotational speed acquisition module; The temperature and speed signals are processed using a DSP closed-loop control module, and the PWM duty cycle d is calculated through dual closed-loop control of temperature and speed. Six voltage signals are generated through a six-channel control signal output module; The six voltage signals are amplified by the drive module and generated to provide the three-phase power bridge module with six voltage signals that meet the turn-on and turn-off requirements. The motor of the rotary Stirling refrigerator is controlled by a three-phase power bridge module, thereby achieving speed and temperature regulation of the rotary Stirling refrigerator.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a dual closed-loop control device and method for temperature and speed of a rotary Stirling refrigerator. By employing a temperature acquisition module, a speed acquisition module, a DSP closed-loop control module, a 6-channel control signal DSP output module, a drive module, and a three-phase power bridge module, it achieves dual closed-loop control of temperature and speed of the rotary Stirling refrigerator, effectively improving temperature control accuracy to ±0.07K and temperature control current fluctuation to ±0.005A, significantly addressing the insufficient temperature control accuracy problem in existing technologies. The speed acquisition module calculates the rotational speed of the rotary Stirling refrigerator in real time, and the DSP closed-loop control module performs closed-loop speed control, effectively improving control stability and solving the problem of poor control stability in existing technologies. The control device of this invention improves temperature control accuracy and control stability, which is beneficial for extending the lifespan of the rotary Stirling refrigerator and broadens its adaptability in military and aerospace applications under the background of domestic production.

[0019] Furthermore, the temperature closed-loop control unit of the present invention adopts a segmented PI control method, which adjusts the proportional control parameter Kp and the integral control parameter Ki in real time according to the temperature difference, thereby improving the accuracy and stability of temperature control. Furthermore, the 6-channel control signal DSP output module of the present invention performs upper bridge filling based on the three Hall signal states and PWM duty cycle d, realizing precise control of the rotary Stirling refrigerator, improving the scalability of the control system, and being able to adapt to the control requirements of rotary Stirling refrigerators of different specifications and models. Furthermore, the three-phase power bridge module of the present invention consists of 6 VDMOS transistors, which can realize the speed regulation of the rotary Stirling refrigerator according to the 6-channel timing voltage signals output by the drive module, significantly improving the practicality and reliability of the control system, which is conducive to reducing dependence on imported products and promoting the application of domestic products. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a block diagram illustrating the principle of a dual closed-loop control device and method for temperature and speed of a rotary Stirling refrigerator according to an embodiment of the present invention. Figure 2 This is a block diagram illustrating the principle of the rotation speed acquisition module in an embodiment of the present invention. Figure 3 This is a block diagram of the DSP control module in an embodiment of the present invention; Figure 4 This is a block diagram of the 6-channel control signal DSP output module in an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] A dual closed-loop control device and method for temperature and speed of a rotary Stirling refrigerator includes a temperature acquisition module, a speed acquisition module, a DSP closed-loop control module, a 6-channel control signal DSP output module, a drive module, and a three-phase power bridge module. The outputs of the temperature acquisition module and the speed acquisition module are both connected to the input of the DSP closed-loop control module. The output of the DSP closed-loop control module is connected to the input of the 6-channel control signal DSP output module. The output of the 6-channel control signal DSP output module is connected to the input of the drive module. The output of the drive module is connected to the input of the three-phase power bridge module. Temperature acquisition module, used to acquire real-time temperature signals from rotary Stirling refrigerator; The speed acquisition module is used to acquire the real-time speed signal of the rotary Stirling refrigerator; The DSP closed-loop control module is used to perform dual closed-loop control calculations based on the acquired temperature and speed signals. A 6-channel control signal DSP output module is used to generate 6 voltage signals; The driving module is used to drive and amplify the six voltage signals. The three-phase power bridge module is used to control the operation of the rotary Stirling refrigerator motor based on the amplified 6-channel voltage signals, thereby achieving speed and temperature regulation. In one preferred embodiment, the temperature acquisition module includes a signal conditioning circuit, an AD conversion circuit, and an SPI transmission circuit; The signal conditioning circuit is used to amplify and filter the analog signal output by the temperature sensor. An AD conversion circuit is used to convert a conditioned analog signal into a digital signal. The SPI transmission circuit is used to transmit digital temperature signals to the DSP closed-loop control module via the SPI interface. The temperature signal is used as the input to the signal conditioning circuit, the output of the signal conditioning circuit is connected to the input of the AD conversion circuit, and the output of the AD conversion circuit is transmitted to the DSP closed-loop control module via SPI.

[0024] In one preferred embodiment, the rotational speed acquisition module includes a DSP capture interrupt unit, a rotational speed calculation unit, and a filtering unit; The DSP capture interrupt unit is used to capture the three-phase Hall position signal output by the Hall sensor of the refrigerator motor; The rotational speed calculation unit is used to calculate the real-time rotational speed n' based on the time difference ΔT between two adjacent capture interruptions. The filtering unit is used to smooth the speed signal, including an average value filter and a low-pass filter; The output of the speed calculation unit After being filtered by the average value, the input is fed into a low-pass filter, and the final output is the smoothed rotational speed n.

[0025] The three-phase Hall position signals of the rotary Stirling refrigerator are used as inputs to the DSP capture interrupt unit. The capture interrupt trigger is set to rising edge capture. The trigger time difference ΔT between two consecutive capture interrupts of the same phase Hall position signal is recorded. The trigger time difference ΔT is used as input for speed calculation. The speed n' calculation formula is as follows:

[0026] Where p is the number of pole pairs of the rotating Stirling refrigerator.

[0027] The output of the speed calculation unit is used as the input of the filtering unit. The filtering unit uses two-stage filtering, namely average value filtering and low-pass filtering, to ensure the stability of the obtained speed.

[0028] The formula for calculating the average filter output n(t) is as follows:

[0029] The speed calculation output n(t) of the average value filter is used as the input of the low-pass filter, and the output n of the low-pass filter is used as the output of the overall speed acquisition module. The specific calculation process is as follows:

[0030] in The output is the rotational speed calculated using the average value filtered at the current moment. The output is the rotational speed calculated based on the average value filtered at the previous moment. α is the filter coefficient of the first-order linear low-pass filter. α determines the cutoff frequency and filtering effect of the filter. The larger α is, the weaker the attenuation of high-frequency signals and the higher the cutoff frequency; the smaller α is, the stronger the attenuation of high-frequency signals and the lower the cutoff frequency.

[0031] The output n of the low-pass filter is the output of the speed acquisition module.

[0032] In one preferred embodiment, the DSP closed-loop control module includes a temperature closed-loop control unit and a speed closed-loop control unit. Temperature closed-loop control unit, used for segmented PI control based on temperature deviation; The speed closed-loop control unit is used for PID control based on speed deviation and outputs PWM duty cycle d.

[0033] In one preferred embodiment, the temperature closed-loop unit comprises: Temperature difference calculation unit, used to calculate the deviation Tup between the set temperature and the actual temperature; The segmented PI controller adaptively adjusts its proportional control parameter Kp and integral control parameter Ki according to the magnitude of Tup; The output of the temperature acquisition module is connected to the input of the DSP closed-loop control module to calculate the temperature difference. The output of the temperature difference calculation is T. up As the input to the segmented PI control, the segmented PI controller uses the temperature difference T... up PI control is performed, outputting a speed reference value. The control parameters of the segmented PI controller include the proportional control parameter Kp and the integral control parameter Ki. Kp and Ki vary with the temperature difference T. up The changes are adaptively adjusted online, and the specific adjustment formula is as follows: First segment: |T up |≥X Second segment: |T up |≤X Among them, Kp max This represents the initial maximum value of the proportional control parameter. X represents the minimum value of the integral control parameter in the second segment, X represents the segment interval, and y represents the rate of change of the integral control parameter in the second segment.

[0034] The inputs to the speed closed-loop control unit include: The speed reference value output by the temperature closed-loop control unit; The actual speed value output by the speed acquisition module; the speed closed-loop control unit adopts a PID control algorithm and outputs a PWM duty cycle d for adjusting the motor speed.

[0035] In one preferred embodiment, the output of the temperature closed-loop control unit and the output of the speed acquisition module are used as the input of the speed control unit. The speed closed-loop control unit adopts PID control and outputs a PWM duty cycle d. The output of the speed closed-loop control unit is the output of the DSP closed-loop control module.

[0036] In one preferred embodiment, the inputs of the 6-channel control signal DSP output module include the output PWM duty cycle d of the DSP closed-loop control module and the three-phase Hall position signal of the rotary Stirling refrigerator. The three-phase Hall signal of the rotary Stirling refrigerator is input to the DSP capture port, and the status identifier of the three-phase Hall signal is ABC. The duty cycle of the PWM wave output by the DSP closed-loop control module is d. The 6-channel control signal DSP output module adopts an upper bridge fill modulation method. In one preferred embodiment, the input of the drive module is connected to the output of the 6-channel control signal DSP output module, providing the three-phase power bridge module with 6 sequential voltage signals that meet the turn-on and turn-off requirements.

[0037] In one preferred embodiment, the three-phase power bridge module consists of six VDMOS transistors. The three-phase power bridge module conducts according to a certain timing and duty cycle based on the six sequential voltage signals output by the drive module to adjust the speed of the rotary Stirling refrigerator, thereby achieving closed-loop control of temperature and speed.

[0038] A method for dual closed-loop control of temperature and speed in a rotary Stirling refrigerator, characterized by comprising the following steps: The real-time temperature of the rotary Stirling refrigerator is obtained through a temperature acquisition module; The real-time rotational speed of the rotary Stirling refrigerator is obtained through the rotational speed acquisition module; The temperature and speed signals are processed using a DSP closed-loop control module, and the PWM duty cycle d is calculated using a dual closed-loop control algorithm for temperature and speed, respectively. Six voltage signals are generated through a six-channel control signal output module; The six voltage signals are amplified by the drive module and generated to provide the three-phase power bridge module with six voltage signals that meet the turn-on and turn-off requirements. The motor of the rotary Stirling refrigerator is controlled by a three-phase power bridge module, thereby achieving speed and temperature regulation of the rotary Stirling refrigerator.

[0039] This invention discloses a dual closed-loop control device and method for temperature and speed of a rotary Stirling refrigerator. It achieves dual closed-loop control of temperature and speed of the rotary Stirling refrigerator through a temperature acquisition module, a speed acquisition module, a DSP closed-loop control module, a 6-channel control signal DSP output module, a drive module, and a three-phase power bridge module. This results in a temperature control accuracy of ±0.07K and a temperature control current fluctuation index of ±0.005A, improving temperature control accuracy and stability, thus extending the lifespan of the rotary Stirling refrigerator. Furthermore, it broadens the adaptability of the refrigerator for applications in military and aerospace fields within the context of domestically produced technology.

[0040] Example 1 like Figure 1 As shown, a dual closed-loop control device and method for temperature and speed of a rotary Stirling refrigerator includes a temperature acquisition module, a speed acquisition module, a DSP closed-loop control module, a 6-channel control signal DSP output module, a drive module, and a three-phase power bridge module. The outputs of the temperature acquisition module and the speed acquisition module are connected to the input of the DSP closed-loop control module. The output of the DSP closed-loop control module is connected to the input of the 6-channel control signal DSP output module. The output of the 6-channel control signal DSP output module is connected to the input of the drive module. The output of the drive module is connected to the input of the three-phase power bridge module.

[0041] Specifically, the rotary Stirling refrigerator consists of a brushless DC motor, mechanical components, and a vacuum cooling chamber. The temperature of the cooling chamber is represented by a voltage signal, which is input to the signal conditioning circuit of the temperature acquisition module. After conditioning, the signal is transmitted to the AD conversion circuit. The AD conversion circuit uses a 16-bit precision domestic chip and outputs a digital voltage signal representing the temperature, which is transmitted to the DSP closed-loop control module via SPI.

[0042] The temperature acquisition module includes a signal conditioning circuit, an AD conversion circuit, and an SPI transmission circuit. The temperature signal serves as the input to the signal conditioning circuit, the output of the signal conditioning circuit is connected to the input of the AD conversion circuit, and the output of the AD conversion circuit is transmitted to the DSP closed-loop control module via SPI.

[0043] like Figure 2 The diagram shows the speed acquisition module. The Hall position signal of the brushless DC motor is input to the DSP capture interrupt unit. The capture interrupt trigger is set to rising edge capture. The trigger time difference ΔT between two consecutive capture interrupts of the same phase Hall position signal is recorded and used as the input for speed calculation. The speed n' calculation formula is as follows:

[0044] Where p is the number of pole pairs in the rotary Stirling refrigerator. In this example, the number of pole pairs of the brushless DC motor in the rotary Stirling refrigerator is 3.

[0045] The output of the speed calculation unit is used as the input of the filtering unit. The filtering unit uses two-stage filtering, namely average value filtering and low-pass filtering, to ensure the stability of the obtained speed.

[0046] The formula for calculating the average value filter output n(t) is as follows:

[0047] The speed calculation output n(t) of the average value filter is used as the input of the low-pass filter, and the output n of the low-pass filter is used as the output of the overall speed acquisition module. The specific calculation process is as follows:

[0048] in, The output is the rotational speed calculated using the average value filtered at the current moment. This is the output of the rotational speed calculated using the average value filtered from the previous moment. α is the filter coefficient of the first-order linear low-pass filter. α determines the filter's cutoff frequency and filtering effect. The larger α is, the weaker the attenuation of high-frequency signals and the higher the cutoff frequency; the smaller α is, the stronger the attenuation of high-frequency signals and the lower the cutoff frequency. In this example, α is set to 0.1096.

[0049] The output n of the low-pass filter is the output of the speed acquisition module.

[0050] like Figure 3 The diagram shows the structure of the DSP closed-loop control module, which includes a temperature closed-loop control unit and a speed closed-loop control unit. The temperature closed-loop unit includes temperature difference calculation and segmented PI control. The output of the temperature acquisition module is connected to the input of the DSP closed-loop control module to perform temperature difference calculation. The output T of the temperature difference calculation... up As the input to the segmented PI control, the segmented PI controller uses the temperature difference T... up PI control is performed, outputting a speed reference value. The control parameters of the segmented PI controller include the proportional control parameter Kp and the integral control parameter Ki. Kp and Ki vary with the temperature difference T. up The changes are adaptively adjusted online, and the specific adjustment formula is as follows: First segment: |T up |≥X Second segment: |T up |≤X Among them, Kp max This represents the initial maximum value of the proportional control parameter. Let X be the minimum value of the integral control parameter in the second segment, X be the segment interval, and y be the rate of change of the integral control parameter in the second segment. In this example... X=0.25 y=0.003.

[0051] The output of the temperature closed-loop control unit serves as the speed reference input of the speed control unit, and the output of the speed acquisition module serves as the actual speed input of the speed closed-loop control unit. The speed closed-loop control unit adopts PID control and outputs a PWM duty cycle d. The output of the speed closed-loop control unit is the output of the DSP closed-loop control module.

[0052] like Figure 4 The diagram shows the structural block diagram of the 6-channel control signal DSP output module. The inputs of this module include the output PWM duty cycle 'd' of the DSP closed-loop control module and the three-phase Hall position signals of the brushless DC motor in the rotary Stirling refrigerator. The three-phase Hall signals of the brushless DC motor are input to the DSP capture port, and their status indicators are ABC. The duty cycle of the PWM wave output by the DSP closed-loop control module is 'd'. The 6-channel control signal DSP output module uses an upper-bridge fill modulation method. The relationship between the 6 control signals, the three-phase Hall signal status ABC, and the PWM duty cycle 'd' is shown in Table 1. Table 1 shows the relationship between the 6-channel control signals and the three-phase Hall signal states ABC and PWM duty cycle d.

[0053] In the table, "0" represents the control signal being off, "1" represents the control signal being on, and "d" represents the control signal being a PWM wave with a duty cycle of d.

[0054] The input of the drive module is connected to the output of the 6-channel control signal DSP output module, providing the power three-phase bridge circuit with 6 sequential voltage signals that meet the turn-on and turn-off voltage requirements.

[0055] The three-phase power bridge module consists of 6 VDMOS transistors. The 6 sequential voltage signals output by the root drive module of the three-phase power bridge module are turned on according to a certain timing and duty cycle to realize the speed regulation of the rotary Stirling refrigerator, thereby realizing closed-loop control of temperature and speed.

[0056] This invention achieves dual closed-loop control of temperature and speed in a rotary Stirling refrigerator by employing a combination design of a temperature acquisition module, a speed acquisition module, a DSP closed-loop control module, a 6-channel control signal DSP output module, a drive module, and a three-phase power bridge module. This effectively improves the temperature control accuracy, achieving a temperature control accuracy of ±0.07K and a temperature control current fluctuation index of ±0.005A, significantly improving the problem of insufficient temperature control accuracy in the prior art. This invention uses a speed acquisition module to calculate the speed of a rotary Stirling refrigerator in real time, and uses a DSP closed-loop control module to perform closed-loop speed control, which effectively improves the stability of control and solves the problem of poor control stability in the prior art. The temperature closed-loop control unit of the present invention adopts a segmented PI control method, which adjusts the proportional parameter Kp and the integral control parameter Ki in real time according to the temperature difference, thereby achieving the accuracy and stability of temperature control. The 6-channel control signal DSP output module of this invention performs bridge filling based on the three Hall signal states and PWM duty cycle d, realizing precise control of the rotary Stirling refrigerator, improving the scalability of the control system, and being able to adapt to the control requirements of rotary Stirling refrigerators of different specifications and models. The three-phase power bridge module of this invention consists of 6 VDMOS transistors, which can realize the speed regulation of the rotary Stirling refrigerator according to the 6-channel timing voltage signal output by the drive module. This significantly improves the practicality and reliability of the control system, helps to reduce dependence on imported products, and promotes the application of domestic products.

[0057] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0058] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. When a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intervening component. When a component is considered to be "set on" another component, it can be directly set on the other component or there may be an intervening component.

[0060] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0061] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A dual closed-loop control device for temperature and speed of a rotary Stirling refrigerator, characterized in that, include: Temperature acquisition module, used to acquire real-time temperature signals from rotary Stirling refrigerator; The speed acquisition module is used to acquire the real-time speed signal of the rotary Stirling refrigerator; The DSP closed-loop control module is used to perform dual closed-loop control calculations based on the acquired temperature and speed signals. A 6-channel control signal DSP output module is used to generate 6 voltage signals; The driving module is used to drive and amplify the six voltage signals. The three-phase power bridge module is used to control the operation of the rotary Stirling refrigerator motor based on the six voltage signals after driving, so as to achieve speed and temperature regulation; The outputs of the temperature acquisition module and the speed acquisition module are both connected to the input of the DSP closed-loop control module. The output of the DSP closed-loop control module is connected to the input of the 6-channel control signal DSP output module. The output of the 6-channel control signal DSP output module is connected to the input of the drive module. The output of the drive module is connected to the input of the three-phase power bridge module.

2. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 1, characterized in that, The temperature acquisition module includes a signal conditioning circuit, an AD conversion circuit, and an SPI transmission circuit. The temperature signal is used as the input to the signal conditioning circuit, the output of which is connected to the input of the AD conversion circuit, and the output of the AD conversion circuit is connected to the input of the DSP closed-loop control module through the SPI transmission circuit.

3. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 1, characterized in that, The speed acquisition module includes a DSP capture interrupt unit, a speed calculation unit, and a filtering unit; the filtering unit includes an average value filter and a low-pass filter. The Hall position signal of the rotary Stirling refrigerator is used as the input of the DSP capture interrupt unit. The trigger time difference ΔT between two consecutive capture interrupts of the same phase Hall position signal is recorded. The trigger time difference ΔT is used as the input of the speed calculation unit, and the output of the speed calculation unit is n'. The specific calculation process is as follows: Where p is the number of pole pairs of the rotating Stirling refrigerator; Output of the speed calculation unit As the input to the averaging filter, the output of the averaging filter is n(t), and the specific calculation process is as follows: The output n(t) of the average value filter is used as the input of the low-pass filter, and the output n of the low-pass filter is used as the output of the overall speed acquisition module. The specific calculation process is as follows: in, The output is the rotational speed calculated by the average filter at the current moment. The output is the rotational speed calculated using the average value filtered from the previous moment, where α is the filter coefficient of the first-order linear low-pass filter.

4. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 1, characterized in that, The DSP closed-loop control module includes: Temperature closed-loop control unit, used for segmented PI control based on temperature deviation; The speed closed-loop control unit is used to perform PID control based on the speed deviation and outputs the PWM duty cycle d. The output of the temperature acquisition module is connected to the input of the temperature closed-loop control unit. The output of the temperature closed-loop control unit and the output of the speed acquisition module serve as the input of the speed closed-loop control unit, and the output of the speed closed-loop control unit serves as the output of the DSP closed-loop control module.

5. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 4, characterized in that, The temperature closed-loop control unit includes: The temperature difference calculation unit is used to calculate the temperature difference T between the set temperature and the actual temperature. up ; The segmented PI controller operates based on the temperature difference T. up PI control is performed, outputting a speed reference value. The control parameters of the segmented PI controller include the proportional control parameter Kp and the integral control parameter Ki. Kp and Ki vary with the temperature difference T. up The changes are adaptively adjusted online, and the specific adjustment formula is as follows: First segment: |T up |≥X Second segment: |T up |≤X Among them, Kp max This represents the initial maximum value of the proportional control parameter. X represents the minimum value of the integral control parameter in the second segment, X represents the segment interval, and y represents the rate of change of the integral control parameter in the second segment.

6. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 4, characterized in that, The inputs to the speed closed-loop control unit include: The speed reference value output by the temperature closed-loop control unit; The actual rotational speed value output by the rotational speed acquisition module; The speed closed-loop control unit uses a PID control algorithm to output the PWM duty cycle d for adjusting the motor speed of the rotary Stirling refrigerator, which is then used as the output of the DSP closed-loop control module.

7. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 1, characterized in that, The inputs of the 6-channel control signal DSP output module include: The output PWM duty cycle d of the DSP closed-loop control module and the three-phase Hall position signal of the rotary Stirling refrigerator; The 6-channel control signal DSP output module outputs 6 voltage signals based on two input signals.

8. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 1, characterized in that, The input of the drive module is connected to the output of the 6-channel control signal DSP output module, and the output of the drive module provides the three-phase power bridge module with 6 voltage signals that meet the turn-on and turn-off requirements.

9. The rotary Stirling refrigerator temperature and speed dual closed-loop control device according to claim 8, characterized in that, The three-phase power bridge module consists of 6 VDMOS transistors, which receive 6 voltage signals output from the drive module to achieve dual closed-loop control of the speed and temperature of the rotary Stirling refrigerator motor.

10. A method for dual closed-loop control of temperature and speed in a rotary Stirling refrigerator, characterized in that, Includes the following steps: The real-time temperature of the rotary Stirling refrigerator is obtained through a temperature acquisition module; The real-time rotational speed of the rotary Stirling refrigerator is obtained through the rotational speed acquisition module; The temperature and speed signals are processed using a DSP closed-loop control module, and the PWM duty cycle d is calculated through dual closed-loop control of temperature and speed. Six voltage signals are generated through a six-channel control signal output module; The six voltage signals are amplified by the drive module to generate six voltage signals that meet the turn-on and turn-off requirements of the three-phase power bridge module. The motor of the rotary Stirling refrigerator is controlled by a three-phase power bridge module, thereby achieving speed and temperature regulation of the rotary Stirling refrigerator.

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