Radio frequency closed-loop decoupling device and method

Abstract

The invention discloses a radio frequency closed-loop decoupling device and method, and the device comprises a radio frequency sampling module which collects a radio frequency signal of a resonant cavity and converts the radio frequency signal into an intermediate frequency signal; the preprocessing module is used for converting the intermediate frequency signal into an I-path signal and a Q-path signal; the extended state observation module is used for obtaining an I component estimated value, a Q component estimated value and a corresponding generalized disturbance estimator according to the I-path signal and the Q-path signal; the decoupling control module is used for carrying out proportional control according to the I component estimation value and the Q component estimation value, and taking the generalized disturbance estimation quantity as decoupling compensation quantity for superposition to obtain a baseband signal so as to suppress channel coupling and external disturbance; and the radio frequency driving module is used for converting the baseband signal into a driving signal so as to control the amplitude and the phase of the radio frequency output of the power source. According to the invention, dynamic decoupling of the I signal channel and the Q signal channel is realized, and the stability and the control precision of the output amplitude and the phase of the power source are improved.

Description

Technical Field

[0001] This invention relates to the field of particle accelerator technology, and more particularly to a radio frequency closed-loop decoupling device and method. Background Technology

[0002] With the development of linear accelerators, storage rings, and industrial radio frequency heating devices, low-level radio frequency (LLRF) control systems for power sources and resonant cavities (LLRF, a fully digital closed-loop feedback control system based on I / Q modulation sampling quadrature demodulation technology, whose main function is to achieve stable control of superconducting cavity voltage amplitude, phase, and cavity resonant frequency) generally adopt amplitude-phase or I / Q methods for closed-loop control to ensure the amplitude and phase stability of the output field. In practical engineering, due to factors such as resonant cavity detuning, transmission line reflection, load changes, and power amplifier nonlinearity, dynamic coupling generally exists between the amplitude loop and phase loop, and between the I channel and Q channel within the RF closed loop. This causes the control action of one channel to generate additional disturbances in another channel, making controller tuning difficult, reducing stability margin, and resulting in insufficient anti-interference performance. Consequently, the decoupling control robustness of the RF closed loop is poor.

[0003] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a radio frequency closed-loop decoupling device and method to solve the problem of obvious dynamic coupling between the I channel and the Q channel in the existing radio frequency closed-loop control.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a radio frequency closed-loop decoupling device, comprising: The radio frequency (RF) sampling module is used to connect to the resonant cavity, acquire the RF signal of the resonant cavity, and convert the RF signal into an intermediate frequency (IF) signal; The preprocessing module, connected to the RF sampling module, is used to convert the intermediate frequency signal into I-channel and Q-channel signals; An extended state observation module, connected to the preprocessing module, is used to obtain I-component estimates and Q-component estimates, as well as corresponding generalized disturbance estimates, based on the I-channel signal and the Q-channel signal. The decoupling control module, connected to the extended state observation module, is used to perform proportional control based on the I component estimate and the Q component estimate, and to superimpose the generalized disturbance estimate as a decoupling compensation quantity to obtain the baseband signal, so as to suppress channel coupling and external disturbances. The radio frequency drive module, connected to the decoupling control module, is used to convert the baseband signal into a drive signal to control the amplitude and phase of the radio frequency output of the power source.

[0006] In a further embodiment of the present invention, the radio frequency sampling module includes: a PT signal probe and a downconverter; The PT signal probe is located inside the resonant cavity and is used to couple the radio frequency signal of the resonant cavity. The downconverter is connected to the PT signal probe and is used to convert the radio frequency signal into an intermediate frequency signal.

[0007] In a further embodiment of the present invention, the preprocessing module includes: an IQ demodulator and an ADC unit; wherein, The ADC unit is connected to the downconverter and is used to acquire intermediate frequency signals; The IQ demodulator is connected to the ADC unit and is used to convert the intermediate frequency signal into I-channel and Q-channel signals, and perform normalization and filtering processing.

[0008] In a further embodiment of the present invention, the radio frequency driving module includes: an IQ modulator, a DAC unit, and an up-converter; wherein, The IQ demodulator is connected to the decoupling control module and is used to convert the baseband signal output by the decoupling control module into an intermediate frequency signal. The DAC unit is connected to the upconverter and is used to convert digital signals into analog signals. The upconverter is connected to the power source and is used to convert the intermediate frequency signal into a radio frequency signal.

[0009] Secondly, the present invention also provides a radio frequency closed-loop decoupling method based on the radio frequency closed-loop decoupling device described above, the method comprising the following steps: The radio frequency (RF) signal of the sampled resonant cavity is converted into an intermediate frequency (IF) signal. Convert the intermediate frequency signal into I-channel and Q-channel signals; Based on the I-channel signal and the Q-channel signal, we obtain the I-component estimate, the Q-component estimate, and the corresponding generalized disturbance estimate; The baseband signal is obtained by proportional control based on the estimated values ​​of the I component and the estimated values ​​of the Q component, and by superimposing the generalized disturbance estimate as a decoupling compensation quantity, so as to suppress channel coupling and external disturbances. The baseband signal is converted into a drive signal to control the power and phase of the RF output of the power source.

[0010] A further provision of the present invention includes the step of obtaining the I-component estimate, the Q-component estimate, and the corresponding generalized disturbance estimate based on the I-channel signal and the Q-channel signal, comprising: Models are established for the I-channel and Q-channel signals respectively, treating detuning, load changes, and uncertainties as generalized disturbances. An extended state observer is constructed for the control channels of the I-channel and Q-channel signals, and the generalized disturbances in the corresponding channels are dynamically estimated, and the coupling term is written into the disturbance term; Extended state observers are established for the I-channel and Q-channel signals respectively, and the estimates of the I-component and Q-component, as well as the corresponding generalized disturbance estimates, are obtained.

[0011] In a further aspect of the present invention, in the step of establishing extended state observers for the I-channel and Q-channel signals respectively, the pole placement method is used to simultaneously determine the parameters of the extended state observers.

[0012] A further provision of this invention, in the step of establishing models for the I-channel and Q-channel signal channels respectively, treating detuning, load variations, and uncertainties as generalized disturbances, employs a first-order linear model to establish models for both the I-channel and Q-channel signal channels; wherein, The model for the I-channel signal is: ; The Q-channel signal model is as follows: ; in: , These are the input control variables for the I and Q components, respectively. , For model parameters, , This represents the disturbance term, which includes interference caused by detuning, load changes, transmission line reflections, power amplifier nonlinearity, and amplitude-phase coupling.

[0013] In a further provision of the present invention, in the steps of dynamically estimating the generalized disturbance within the corresponding channel and writing the coupling term into the disturbance term, the expression for the disturbance term is: ; in, , Represents the coupling coefficient. , For other unknown disturbances; In the step of establishing extended state observers for the I-channel and Q-channel signal channels respectively, the extended state observer for the I-channel signal channel is represented as follows: ; The extended state observer for the Q-channel signal is represented as follows: ; in, , These are the estimated values ​​for the I and Q components, respectively. , These are the estimates of the corresponding disturbances. , , , To extend the parameters of the state observer.

[0014] A further provision of the present invention includes a step in which proportional control is performed based on the estimated I-component and the estimated Q-component, and the generalized disturbance estimate is superimposed as a decoupling compensation quantity to obtain a control quantity, thereby suppressing channel coupling and external disturbances. The control variables for the I-channel signal are represented as follows: ; The control variables for the Q-channel signal are represented as follows: ; in, , These are the reference values ​​for I and Q, respectively. , This is the proportional integral coefficient.

[0015] This invention provides a radio frequency closed-loop decoupling device and method. The device includes: a radio frequency sampling module connected to a resonant cavity, for acquiring the radio frequency signal of the resonant cavity and converting the radio frequency signal into an intermediate frequency signal; a preprocessing module connected to the radio frequency sampling module, for converting the intermediate frequency signal into an I-channel signal and a Q-channel signal; an extended state observation module connected to the preprocessing module, for obtaining I-component estimates and Q-component estimates, as well as corresponding generalized disturbance estimates, based on the I-channel signal and the Q-channel signal; a decoupling control module connected to the extended state observation module, for performing proportional control based on the I-component estimates and Q-component estimates, and superimposing the generalized disturbance estimates as decoupling compensation to obtain a baseband signal to suppress channel coupling and external disturbances; and a radio frequency driving module connected to the decoupling control module, for converting the baseband signal into a driving signal to control the amplitude and phase of the radio frequency output of the power source. This invention uses an extended state observation module to estimate the generalized disturbances of the I and Q signal channels in real time, and then superimposes the generalized disturbance estimates as decoupling compensation quantities to obtain the baseband signal. This suppresses channel coupling and external disturbances, realizes dynamic decoupling of the I and Q signal channels, improves the stability and control accuracy of the power source output amplitude and phase, and thus improves the control robustness of RF closed-loop decoupling. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a radio frequency closed-loop decoupling device in one embodiment of the present invention.

[0018] Figure 2 This is a flowchart illustrating a radio frequency closed-loop decoupling method in one embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram illustrating the principle of dynamic decoupling between the I and Q channels in one embodiment of the present invention.

[0020] Figure 4 This is the normalized amplitude noise diagram of the system during open-loop control.

[0021] Figure 5 This is the phase noise diagram of the system during open-loop control.

[0022] Figure 6 This is the normalized amplitude noise diagram of the system under PI control.

[0023] Figure 7 This is the system phase noise diagram under PI control.

[0024] Figure 8 This is a normalized amplitude noise diagram of the control system in one embodiment of the present invention.

[0025] Figure 9 This is a phase noise diagram of the control system in one embodiment of the present invention.

[0026] The following are the labels in the attached diagram: 1. RF sampling module; 11. PT signal probe; 12. Down-converter; 2. Preprocessing module; 21. IQ demodulator; 22. ADC unit; 3. Extended state observation module; 4. Decoupling control module; 5. RF drive module; 51. IQ modulator; 52. DAC unit; 53. Up-converter; 6. Power source; 7. Resonant cavity. Detailed Implementation

[0027] This invention provides a radio frequency closed-loop decoupling device and method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0028] In the implementation methods and claims, unless otherwise specified in the text, the terms "a," "an," "the," and "the" may also include plural forms. If the embodiments of the present invention involve descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0029] It should be further understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements present. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any of the units and all combinations thereof of one or more associatedly listed items.

[0030] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0031] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0032] The inventors discovered that in practical engineering, due to factors such as resonant cavity detuning, transmission line reflection, load variations, and power amplifier nonlinearity, dynamic coupling commonly exists within the RF closed loop between the amplitude loop and phase loop, and between the I and Q channels. This causes the control action of one channel to generate additional disturbances in the other channel, making controller tuning difficult, reducing stability margin, and resulting in insufficient noise immunity, thus leading to poor robustness of the decoupled control in the RF closed loop. To address this, existing solutions are based on an equivalent first-order linear model of the resonant cavity. The probe signals from each resonant cavity are down-converted and analog-to-digital converted to obtain I and Q components. The I / Q components from multiple cavities are weighted and summed to form a vector sum signal, which is then used for closed-loop control in the I / Q plane. The system employs a proportional-integral (PI) controller to provide feedback adjustment for vector and amplitude errors. To reduce the coupling between amplitude and phase, the system is linearized under conditions where the resonant frequency is close to the nominal value, approximating amplitude-phase decoupling within a small range. Simultaneously, modules such as a resonant frequency control loop and beam feedforward compensation are used to improve overall stability. This type of scheme relies on a fixed decoupling matrix and PI parameters obtained under the linearization assumption. When the resonant cavity detunes with time, the transmission line matching conditions change, or the power amplifier enters the nonlinear region, the original decoupling relationship is easily disrupted, and the amplitude control action will still cause significant phase disturbances. In order to ensure stability margin under various operating conditions, the PI parameters often need to be set conservatively, which has limited ability to suppress rapid disturbances and makes it difficult to meet the requirements of high-precision amplitude and phase stabilization. At the same time, this scheme does not model and treat the coupling of the I / Q channels as a unified source of disturbance, and cannot achieve adaptive dynamic decoupling at the controller level.

[0033] To address the aforementioned technical problems, this invention provides a radio frequency closed-loop decoupling device and method. By extending the state observation module, the generalized disturbances of the I signal channel and the Q signal channel are estimated in real time, and the generalized disturbance estimates are superimposed as decoupling compensation quantities to obtain the baseband signal. This suppresses channel coupling and external disturbances, achieving dynamic decoupling of the I signal channel and the Q signal channel. This improves the stability and control accuracy of the power source output amplitude and phase, thereby enhancing the control robustness of the radio frequency closed-loop decoupling.

[0034] Please also refer to Figures 1 to 2 The present invention provides a preferred embodiment of a radio frequency closed-loop decoupling device.

[0035] In some embodiments, such as Figure 1As shown, this invention provides a radio frequency closed-loop decoupling device, comprising: a radio frequency sampling module 1, a preprocessing module 2, an extended state observation module 3, a decoupling control module 4, and a radio frequency driving module 5. The radio frequency sampling module 1 is connected to a resonant cavity 7, acquiring the radio frequency signal of the resonant cavity 7 and converting the radio frequency signal into an intermediate frequency signal. The preprocessing module 2 is connected to the radio frequency sampling module 1, converting the intermediate frequency signal into an I-channel signal and a Q-channel signal. The extended state observation module 3 is connected to the preprocessing module 2, obtaining I-component estimates and Q-component estimates, as well as corresponding generalized disturbance estimates, based on the I-channel signal and the Q-channel signal. The decoupling control module 4 is connected to the extended state observation module 3, performing proportional control based on the I-component estimates and Q-component estimates, and superimposing the generalized disturbance estimates as decoupling compensation to obtain a baseband signal, thereby suppressing channel coupling and external disturbances. The radio frequency driving module 5 is connected to the decoupling control module 4, converting the baseband signal into a driving signal to control the amplitude and phase of the radio frequency output of the power source 6.

[0036] In this embodiment, the power source 6 is connected to the resonant cavity 7, providing a radio frequency (RF) signal to the resonant cavity 7. The power source 6, the resonant cavity 7, the RF sampling module 1, the preprocessing module 2, the extended state observation module 3, the decoupling control module 4, and the RF drive module 5 constitute a closed-loop resonant cavity 7. The RF sampling module 1 is connected to the output, forward, reflective, or probe ends of the resonant cavity 7 to couple out the RF signal and can convert the RF signal into an intermediate frequency (IF) signal that is easy to modulate. After passing through the preprocessing module 2, the IF signal can output one I-channel signal and one Q-channel signal, and the two signals are normalized and filtered respectively. The extended state observation module 3 can estimate the generalized disturbance of the I-channel and Q-channel signal channels in real time, and obtain the estimated values ​​of the I-component and Q-component, as well as the corresponding generalized disturbance estimates, based on the I-channel and Q-channel signals. The extended state observation module 3 employs an extended state observer, with extended state observers set up on each of the I / Q channels to estimate the generalized disturbances of each channel in real time, providing a basis for decoupling and disturbance rejection. The extended state observer can be implemented in an FPGA control board and supports online adjustment of the observer bandwidth and gain parameters to adapt to the characteristics of different resonant cavities 7 and power sources 6.

[0037] The decoupling control module 4 employs an ADRC (Active Disturbance Rejection Control) controller, capable of proportional control based on the reference value and the estimated I-component and Q-component values. It supports a first-order ADRC structure and superimposes the generalized disturbance estimate as a decoupling compensation to obtain the baseband signal, thereby suppressing coupling between the I-channel and Q-channel signals and external disturbances. The RF drive module 5 converts the baseband signal into an RF signal to drive the power source 6, enabling amplitude and phase control of the RF output.

[0038] In the above technical solution, this invention uses the extended state observation module 3 to estimate the generalized disturbances of the I and Q signal channels in real time, and then superimposes the generalized disturbance estimates as decoupling compensation quantities to obtain the baseband signal. This suppresses channel coupling and external disturbances, achieving dynamic decoupling between the I and Q signal channels. This improves the stability and control accuracy of the output amplitude and phase of the power source 6, thereby enhancing the control robustness of the RF closed-loop decoupling. Because the generalized disturbances are observed and compensated in real time, this invention can effectively suppress the effects of power grid fluctuations, power amplifier gain drift, and slow resonant frequency drift on the closed loop. Furthermore, the observer gain, controller bandwidth, and reference value can all be adjusted online, enabling the system to adapt to changes in the operating point and long-term drift. Moreover, each module is packaged as a modular device that can run on an FPGA, making it suitable for RF systems with different frequencies and resonant structures. In terms of implementation cost, it only adds a small amount of multiply-accumulate operations and register resources to the existing digital LLRF system, without changing the RF front-end hardware structure. It is easy to integrate into existing equipment through firmware upgrades, resulting in low engineering implementation costs.

[0039] In some embodiments, such as Figure 1 As shown, the radio frequency sampling module 1 includes: a PT signal probe 11 and a downconverter 12; the PT signal probe 11 is partially located inside the resonant cavity 7 and is used to collect the radio frequency signal output by the resonant cavity 7; the downconverter 12 is connected to the PT signal probe 11 and is used to convert the radio frequency signal into an intermediate frequency signal.

[0040] In some embodiments, the sampling of the radio frequency signal is achieved by a PT signal probe 11, which is partially located within the resonant cavity 7 and is part of the resonant cavity system capable of acquiring the radio frequency signal of the resonant cavity 7. The downconverter 12 is connected between the PT signal probe 11 and the preprocessing module 2, and is capable of converting the radio frequency signal into an intermediate frequency signal.

[0041] In some embodiments, such as Figure 1As shown, the preprocessing module 2 includes an IQ demodulator 21 and an ADC unit 22; wherein, the ADC unit 22 is connected to the downconverter 12 and is used to acquire intermediate frequency signals; the IQ demodulator 21 is connected to the ADC unit 22 and is used to convert the intermediate frequency signals into I-channel signals and Q-channel signals, and perform normalization and filtering processing.

[0042] In this embodiment, the ADC sampling unit acquires the intermediate frequency (IF) signal, which is then converted into two signals by the IQ demodulator 21: one I-channel signal and the other Q-channel signal. These two signals are further digitally filtered, and their gain and phase corrected before being fed back to the extended state observation module 3. Each signal channel is connected to one branch of the extended state observation module 3 and the decoupling control module 4. In this embodiment, the sampling frequency of the ADC unit 22 is 108.3333MHz.

[0043] In some embodiments, such as Figure 1 As shown, the RF drive module 5 includes an IQ modulator 51, a DAC unit 52, and an upconverter 53. The IQ demodulator 51 is connected to the decoupling control module 4 and is used to modulate the baseband signal output by the decoupling control module 4 into an intermediate frequency (IF) signal. The DAC unit 52 is connected to the upconverter and is used to convert digital signals into analog signals. The upconverter 53 is connected to the power source 6 and is used to convert the IF signal into an RF signal.

[0044] In this embodiment, the baseband signal output by the decoupling control module 4 is modulated into an intermediate frequency signal (digital signal) by the IQ modulator 51 and then input to the DAC unit 52. After passing through the DAC unit 52, the output is converted into an analog signal and input to the upconverter 53. The upconverter 53 converts the intermediate frequency signal into a radio frequency signal to drive the power source 6. The output of the power source 6 is resampled and fed back after passing through the resonant cavity 7 and the transmission line, forming a complete closed loop.

[0045] In some embodiments, the preprocessing module 2, the extended state observation module 3, the decoupling control module 4, and the DAC unit 51 and IQ modulator 52 in the RF drive module 5 can be integrated into the same FPGA firmware algorithm.

[0046] In some embodiments, such as Figure 2 As shown, the present invention also provides a radio frequency closed-loop decoupling method based on the above-described radio frequency closed-loop decoupling device, the method comprising the following steps: S100 samples the radio frequency signal of the resonant cavity and converts the radio frequency signal into an intermediate frequency signal; Specifically, after the RF sampling module samples the RF signal of the resonant cavity, it can convert the RF signal into an intermediate frequency signal and input it to the preprocessing module.

[0047] S200: Converts the intermediate frequency signal into I-channel and Q-channel signals; Specifically, after receiving the intermediate frequency signal, the preprocessing module can convert the intermediate frequency signal into two signals, one of which is an I signal and the other is a Q signal, and can perform normalization and filtering on the two signals.

[0048] S300. Obtain the I component estimate, the Q component estimate, and the corresponding generalized disturbance estimate based on the I-channel signal and the Q-channel signal; Specifically, the I-channel signal and the Q-channel signal are respectively input to an extended state observation module. The extended state observation module can obtain the I-component estimate and the Q-component estimate, as well as the generalized disturbance estimate corresponding to the I-channel signal and the Q-channel signal, based on the I-channel signal and the Q-channel signal.

[0049] S400. The I component estimate and the Q component estimate are proportionally controlled, and the generalized disturbance estimate is superimposed as a decoupling compensation quantity to obtain the baseband signal, so as to suppress channel coupling and external disturbances. Specifically, the decoupling control module receives a reference value and calculates the difference between it and the estimated values ​​of the input I and Q components to obtain the control error. This error is then used by a proportional controller to generate a basic control quantity. The disturbance estimate is further subtracted from the control law, and the result is divided by the input gain to obtain the actual control quantity required to be input to the resonant cavity. A unified or simplified parameter tuning strategy is used for the decoupled I and Q channels. That is, both the I and Q signals are treated as the same equivalent first-order SISO (Single-Input Single-Output) object, and the ESO parameters are simultaneously determined using a unified pole method.

[0050] S500: Convert the baseband signal into a drive signal to control the amplitude and phase of the RF output of the power source.

[0051] Specifically, an RF drive module is used to convert the baseband signal output by the decoupling control module to obtain an RF signal for driving the power source, thereby achieving power and phase control of the RF output of the power source.

[0052] In the above technical solution, the present invention estimates the generalized disturbances of the I signal channel and the Q signal channel in real time by extending the state observation module, and superimposes the generalized disturbance estimates as decoupling compensation quantities to obtain the baseband signal, so as to suppress channel coupling and external disturbances, realize the dynamic decoupling of the I signal channel and the Q signal channel, improve the stability and control accuracy of the power source output amplitude and phase, and thus improve the control robustness of RF closed-loop decoupling.

[0053] In some embodiments, the step of obtaining I-component estimates and Q-component estimates, as well as corresponding generalized disturbance estimates, from the I-channel signal and the Q-channel signal includes: S310. Treating detuning, load changes, and uncertainties as generalized disturbances, models are established for the I-channel and Q-channel signals respectively. S320. Construct an extended state observer for the control channels of the I-channel and Q-channel signals, dynamically estimate the generalized disturbances in the corresponding channels, and write the coupling term into the disturbance term; S330. Establish extended state observers for the I-channel and Q-channel signals respectively, and obtain the I-component estimates, Q-component estimates, and corresponding generalized disturbance estimates.

[0054] Specifically, a dynamic model of the RF closed loop is established in the I-component and Q-component coordinate system. Uncertain factors such as detuning, load changes, and coupling are treated as generalized disturbances, and models are established for the I-signal channel and the Q-signal channel respectively.

[0055] In this embodiment, using a first-order linear model, the I-channel signal can be represented as: ; The Q-channel signal model is as follows: ; in: , These are the input control variables for the I and Q components, respectively. , For model parameters, , This represents the disturbance term, which includes interference caused by detuning, load changes, transmission line reflections, and amplitude-phase coupling.

[0056] Subsequently, an extended state observer is constructed for each independent control channel, and the generalized disturbances within the control channel are estimated in real time. If coupling exists in the system, the coupling term is written into the disturbance term. The expression for the disturbance term is: ; in, , Represents the coupling coefficient. , For other unknown disturbances, this embodiment does not require precise parameters for these disturbances. Instead, it estimates them using an extended state observer. That is, the generalized disturbance is added to the I-channel or Q-channel signal as an extended state, and then the generalized disturbance is reconstructed using observation error feedback.

[0057] After obtaining the disturbance terms for both signal channels, extended state observers are established for the I-channel and Q-channel signal channels respectively. The extended state observer for the I-channel signal channel is expressed as follows: ; The extended state observer for the Q-channel signal is represented as follows: ; in, , These are the estimated values ​​for the I and Q components, respectively. , These are the estimates of the corresponding disturbances. , , , The parameters are for the extended state observer. It should be noted that when determining the parameters of the extended state observer to implement the extended stater, the dynamic response of the extended state observer needs to be faster than the closed-loop response of the RF cavity, that is, the disturbance needs to be estimated and suppressed before the early disturbance causes error.

[0058] In some embodiments, in the step of establishing extended state observers for the I-channel and Q-channel signal channels respectively, the pole placement method is used to simultaneously determine the parameters of the extended state observers.

[0059] For example, when the cavity uses a proportional controller, the closed-loop poles are: ; in This is the proportional gain, which is determined by the desired perturbation suppression factor achievable at the cavity field. In this embodiment, all poles of the observer are placed in the same location: , The value is between 3 and 10.

[0060] Therefore, the characteristic polynomial of the I-channel observer is: ; If the two poles of the observer are set at the same location, then the expected characteristic polynomial is: ; ; By comparing the two formulas, we can obtain the parameters of the I-channel observer: ; Similarly, the Q-channel observer parameters can be obtained: The calculations showed that the observer parameters for both channels were the same.

[0061] In some embodiments, in the step of performing proportional control based on the I-component estimates and Q-component estimates, and superimposing the generalized disturbance estimate as a decoupling compensation quantity to obtain the control quantity, in order to suppress channel coupling and external disturbances... The control variables for the I-channel signal are represented as follows: ; The control variables for the Q-channel signal are represented as follows: ; in, , These are the reference values ​​for I and Q, respectively. , This is the proportional integral coefficient.

[0062] Specifically, please combine Figure 3 ,in, Figure 3 In the diagram, 'a' represents the principle of dynamic decoupling of the I-channel. Figure 3 In the diagram, 'b' represents the principle of dynamic decoupling in the Q channel. Both the I-channel and Q-channel signal paths are first-order ADRC (including ESO) + decoupling compensation closed loops. Taking the I-channel as an example, the extended state observer of the I-channel first obtains the estimated value of the I-component and the generalized disturbance estimate of the I-channel based on the input I-component. Subsequently, proportional control is performed in the decoupling controller of the I-channel. First, the difference between the input reference value and the feedback I-component estimate is calculated to obtain the control error. The control error is then used by the proportional controller to generate the basic control quantity. The generalized disturbance estimate is then subtracted from the control law, and the result is divided by the input gain to obtain the control quantity of the actual input resonant cavity. The resonant cavity, acting as the controlled object, outputs an I component. The extended state observer controls the output through the control quantity. The output reconstruction state and disturbance acquired by the resonant cavity.

[0063] In this embodiment, the present invention divides the RF closed loop into corresponding I-signal channels and Q-signal channels. Each channel includes an active disturbance rejection controller and an extended state observer. The disturbance estimate output by the extended state observer is introduced into the control law as a decoupling compensation term, which significantly weakens the dynamic coupling between the I / Q control quantities, forming mutually independent equivalent single-input single-output control objects. This allows for real-time compensation for generalized disturbances caused by detuning, load changes, and channel coupling, achieving dynamic decoupling between the I-signal channel and the Q-signal channel.

[0064] To verify the effectiveness of the present invention, experimental tests were conducted on the invention, such as... Figure 4 and Figure 5 As shown, with the resonant cavity detuned at 13.8 Hz, and the I and Q channel noise being 0.5-50 Hz Gaussian white noise, the RMS (Root Mean Square) of the amplitude is 0.0169 and the RMS of the phase is 0.9950° when the system is open-loop controlled. When using PI control, the RMS of the amplitude is 0.0021 and the RMS of the phase is 0.1350°. The results are as follows... Figure 6 and Figure 7 As shown; using the structure of this invention, the RMS of the amplitude is 1.6847e-4, and the RMS of the phase is 0.0108°, as shown in the figure. Figure 8 and Figure 9 As shown, the present invention significantly outperforms the PI scheme in improving the control effect of amplitude and phase.

[0065] In summary, the radio frequency closed-loop decoupling device and method provided by the present invention have the following beneficial effects: By extending the state observation module, the generalized disturbances of the I signal channel and the Q signal channel are estimated in real time, and the generalized disturbance estimates are superimposed as decoupling compensation quantities to obtain the baseband signal. This suppresses channel coupling and external disturbances, realizes dynamic decoupling of the I signal channel and the Q signal channel, improves the stability and control accuracy of the power source output amplitude and phase, and thus improves the control robustness of RF closed-loop decoupling. Since the generalized disturbance is observed and compensated in real time, the effects of power grid fluctuations, power amplifier gain drift, and slow resonant frequency drift on the closed loop can be effectively suppressed. After decoupling, each channel can be regarded as a first-order linear object, and the parameter setting can be completed by using a unified bandwidth tuning method, avoiding the cumbersome multi-variable tuning process in traditional coupled systems. Packaged as a modular device that can run on an FPGA, it is suitable for RF systems with different frequencies and resonant structures, and has strong versatility. It only requires adding a small amount of multiply-accumulate operations and register resources to the existing digital LLRF system, without changing the RF front-end hardware structure. It is easy to integrate into existing devices through firmware upgrades, resulting in low engineering implementation costs.

[0066] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A radio frequency closed-loop decoupling device, characterized in that, include: The radio frequency (RF) sampling module is used to connect to the resonant cavity, acquire the RF signal of the resonant cavity, and convert the RF signal into an intermediate frequency (IF) signal; The preprocessing module, connected to the RF sampling module, is used to convert the intermediate frequency signal into I-channel and Q-channel signals; An extended state observation module, connected to the preprocessing module, is used to obtain I-component estimates and Q-component estimates, as well as corresponding generalized disturbance estimates, based on the I-channel signal and the Q-channel signal. The decoupling control module, connected to the extended state observation module, is used to perform proportional control based on the I component estimate and the Q component estimate, and to superimpose the generalized disturbance estimate as a decoupling compensation quantity to obtain the baseband signal, so as to suppress channel coupling and external disturbances. The radio frequency drive module, connected to the decoupling control module, is used to convert the baseband signal into a drive signal to control the amplitude and phase of the radio frequency output of the power source.

2. The radio frequency closed-loop decoupling device according to claim 1, characterized in that, The radio frequency sampling module includes: a PT signal probe and a downconverter; The PT signal probe is located inside the resonant cavity and is used to acquire the radio frequency signal output by the resonant cavity. The downconverter is connected to the PT signal probe and is used to convert the radio frequency signal into an intermediate frequency signal.

3. The radio frequency closed-loop decoupling device according to claim 2, characterized in that, The preprocessing module includes: an IQ demodulator and an ADC unit; wherein... The ADC unit is connected to the downconverter and is used to acquire intermediate frequency signals; The IQ demodulator is connected to the ADC unit and is used to convert the intermediate frequency signal into I-channel and Q-channel signals, and perform normalization and filtering processing.

4. The radio frequency closed-loop decoupling device according to claim 3, characterized in that, The radio frequency drive module includes: an IQ modulator, a DAC unit, and an up-converter; wherein... The IQ demodulator is connected to the decoupling control module and is used to modulate the baseband signal output by the decoupling control module into an intermediate frequency signal. The DAC unit is connected to the upconverter and is used to convert digital signals into analog signals. The upconverter is connected to the power source and is used to convert the intermediate frequency signal into a radio frequency signal.

5. A radio frequency closed-loop decoupling method based on the radio frequency closed-loop decoupling device according to any one of claims 1-4, characterized in that, The method includes the following steps: The radio frequency (RF) signal of the sampled resonant cavity is converted into an intermediate frequency (IF) signal. Convert the intermediate frequency signal into I-channel and Q-channel signals; Based on the I-channel signal and the Q-channel signal, we obtain the I-component estimate, the Q-component estimate, and the corresponding generalized disturbance estimate; The baseband signal is obtained by proportional control based on the estimated values ​​of the I component and the estimated values ​​of the Q component, and by superimposing the generalized disturbance estimate as a decoupling compensation quantity, so as to suppress channel coupling and external disturbances. The baseband signal is converted into a drive signal to control the amplitude and phase of the RF output of the power source.

6. The radio frequency closed-loop decoupling method according to claim 5, characterized in that, The steps of obtaining the I-component estimates, Q-component estimates, and corresponding generalized disturbance estimates based on the I-channel signal and the Q-channel signal include: Models are established for the I-channel and Q-channel signals respectively, treating detuning, load changes, and uncertainties as generalized disturbances. An extended state observer is constructed for the control channels of the I-channel and Q-channel signals, and the generalized disturbances in the corresponding channels are dynamically estimated, and the coupling term is written into the disturbance term; Extended state observers are established for the I-channel and Q-channel signals respectively, and the estimates of the I-component and Q-component, as well as the corresponding generalized disturbance estimates, are obtained.

7. The radio frequency closed-loop decoupling method according to claim 6, characterized in that, In the step of establishing extended state observers for the I-channel and Q-channel signals respectively, the pole placement method is used to simultaneously determine the parameters of the extended state observers.

8. The radio frequency closed-loop decoupling method according to claim 6, characterized in that, In the step of modeling the I-channel and Q-channel signals separately, treating detuning, load variations, and uncertainties as generalized disturbances, a first-order linear model is used to model both the I-channel and Q-channel signals respectively; where... The model for the I-channel signal is: ； The Q-channel signal model is as follows: ； in: , These are the input control variables for the I and Q components, respectively. , For model parameters, , This represents the disturbance term, which includes interference caused by detuning, load changes, transmission line reflections, and amplitude-phase coupling.

9. The radio frequency closed-loop decoupling method according to claim 8, characterized in that, In the steps of dynamically estimating the generalized perturbation within the corresponding channel and incorporating the coupling term into the perturbation term, the expression for the perturbation term is: ； in, , Represents the coupling coefficient. , For other unknown disturbances; In the step of establishing extended state observers for the I-channel and Q-channel signal channels respectively, the extended state observer for the I-channel signal channel is represented as follows: ； The extended state observer for the Q-channel signal is represented as follows: ； in, , These are the estimated values ​​for the I and Q components, respectively. , These are the estimates of the corresponding disturbances. , , , To extend the parameters of the state observer.

10. The radio frequency closed-loop decoupling method according to claim 5, characterized in that, In the steps of proportional control based on the estimated I-component and Q-component values, and superimposing the generalized disturbance estimate as a decoupling compensation quantity to obtain the baseband signal, in order to suppress channel coupling and external disturbances... The control variables for signal channel I are represented as follows: ； The control variables for the Q-channel signal are represented as follows: ； in, , These are the reference values ​​for I and Q, respectively. , This is the proportional integral coefficient.

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