Coil current feedback control system and control method

Abstract

The invention relates to the technical field of electronic circuits, and discloses a coil current feedback control system and method, and the system comprises a signal generator and a power amplifier which are used for supplying power to a target coil; the current acquisition sensor is used for acquiring the real-time current of the target coil; and the processing module is used for comparing the real-time current with a target current of the target coil, and sending a control instruction to the power amplifier when the real-time current is not equal to the target current, so as to adjust the gain of the power amplifier and adjust the real-time current of the target coil to the target current. According to the invention, through real-time measurement and feedback control of the coil current, automatic adjustment of the gain of the power amplifier is realized, and accurate control of the coil current is further realized.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and particularly to a coil current feedback control system and a control method. Background Art

[0002] Coils are key components in many electrical and electronic devices and are widely used in fields such as electromagnetic induction heating, wireless energy transfer, motor drive, and sensor detection. For example, a coil can generate a magnetic field or induced current through current excitation, thereby achieving energy conversion or signal transmission. However, in practical applications, the current instability of coils is a common technical problem, which seriously affects the performance, efficiency, and reliability of devices.

[0003] The current instability of coils may be caused by various factors, including but not limited to:

[0004] Power supply fluctuations: Voltage or frequency fluctuations in the input power supply will directly cause instability of the coil current.

[0005] Load changes: Dynamic changes in the load (such as impedance changes or load mutations) will affect the current response of the coil.

[0006] Environmental interference: External electromagnetic interference or temperature changes may cause fluctuations in the coil current.

[0007] The instability of the coil current will cause a series of technical problems, including:

[0008] Reduced energy conversion efficiency: Current fluctuations will cause increased energy losses and reduce the overall efficiency of the system.

[0009] Degraded device performance: For example, in electromagnetic heating applications, current instability will cause uneven heating and affect the heating effect.

[0010] Reduced system reliability: Severe fluctuations in current may damage the coil or other electronic components and shorten the service life of the device.

[0011] Limited control accuracy: In scenarios that require high-precision current control (such as medical devices or precision instruments), current instability will directly affect the performance and safety of the device. Summary of the Invention

[0012] In view of this, the present invention provides a coil current feedback control system and a control method to solve the problem of coil current instability.

[0013] In a first aspect, the present invention provides a coil current feedback control system, which includes:

[0014] A signal generator and a power amplifier for supplying power to a target coil;

[0015] A current acquisition sensor for acquiring the real-time current of the target coil;

[0016] A processing module for comparing the real-time current with the target current of the target coil, and when the real-time current is not equal to the target current, sending a control instruction to the power amplifier to adjust the gain of the power amplifier so that the real-time current of the target coil is adjusted to the target current.

[0017] In an optional embodiment, the target coil is an excitation coil in a magnetic nanoparticle imaging device.

[0018] In an optional embodiment, the processing module includes: a controller, a processor, and a memory;

[0019] The controller includes: a cache and a data transmission control unit;

[0020] The cache is used to receive and cache the electrical signal corresponding to the real-time current;

[0021] The data transmission control unit is used to read the electrical signal corresponding to the real-time current from the cache and write it into the memory;

[0022] The processor is used to read the electrical signal corresponding to the real-time current from the memory, and based on the electrical signal corresponding to the real-time current, calculate the effective value of the real-time current;

[0023] The processor is further used to generate the control instruction according to the deviation between the effective value of the real-time current and the target current.

[0024] In an optional embodiment, the system further includes: an analog-to-digital converter; the analog-to-digital converter is used to receive the voltage signal corresponding to the real-time current output by the current acquisition sensor, and convert the voltage signal corresponding to the real-time current into a digital voltage signal and transmit it to the cache.

[0025] In an optional embodiment, the processor is specifically used to, after reading the digital voltage signal corresponding to the real-time current from the memory, convert the digital voltage signal corresponding to the real-time current into an analog voltage signal; obtain the maximum voltage value and the minimum voltage value of the analog voltage signal within a current change period, where the current change period is the current change period on the target coil; determine the effective value of the real-time current based on the maximum voltage value, the minimum voltage value, and a conversion coefficient, where the conversion coefficient is the conversion coefficient between the input current and the output voltage of the current acquisition sensor.

[0026] In an alternative embodiment, the digital voltage signal corresponding to the real-time current is converted into an analog voltage signal by the following formula:

[0027]

[0028] where V is the value of the analog voltage signal, Va is the value of the digital voltage signal, Va min and Va max are the lower limit value and the upper limit value of the digital voltage signal, and Vo min and Vo max are the values of the analog voltage signals corresponding to the lower and upper limit values of the digital voltage signal.

[0029] In an alternative embodiment, the universal asynchronous receiver-transmitter (UART) communication method is adopted between the processing module and the power amplifier.

[0030] In a second aspect, the present invention provides a coil current feedback control method, which is applied to the processing module in the coil current feedback control system according to the first aspect or any corresponding embodiment thereof. The method includes:

[0031] Comparing the real-time current of the target coil with the target current, where the real-time current is collected by a current acquisition sensor;

[0032] When the real-time current is not equal to the target current, generating and sending a control instruction to the power amplifier to adjust the gain of the power amplifier so that the real-time current of the target coil is adjusted to the target current.

[0033] In an alternative embodiment, the step of generating and sending a control instruction to the power amplifier when the real-time current is not equal to the target current includes:

[0034] Calculating the error between the target current and the real-time current and the corresponding error change rate;

[0035] Using the error and the error change rate as inputs and generating a voltage control result by fuzzy logic inference;

[0036] Generating the control instruction based on the voltage control result;

[0037] Sending the control instruction to the power amplifier.

[0038] In an alternative embodiment, the step of using the error and the error change rate as inputs and generating a voltage control result by fuzzy logic inference includes:

[0039] The error and the error change rate are respectively scaled to the input universe of discourse range of the fuzzy controller by using a pre-determined error quantization factor and an error change rate quantization factor;

[0040] The scaled error and the error change rate are respectively matched with the pre-divided input fuzzy subsets to determine the input fuzzy subsets to which they belong and the corresponding first membership degrees;

[0041] Using preset fuzzy rules, based on the input fuzzy subsets to which the error and the error change rate belong and the corresponding first membership degrees, a fuzzy output is determined, and the fuzzy output is the output fuzzy subset and the second membership degree to which the proportional and integral coefficient increments belong;

[0042] The fuzzy output is defuzzified and converted into corresponding proportional and integral coefficient increments;

[0043] The proportional and integral coefficient increments are added to the initial proportional and initial integral coefficients to obtain the final proportional and integral coefficients;

[0044] Based on the final proportional and integral coefficients, the voltage control result is generated.

[0045] In a third aspect, the present invention provides a coil current feedback control device, which is applied to a processing module in the coil current feedback control system according to the first aspect or any corresponding embodiment thereof. The device includes:

[0046] A comparison module for comparing the real-time current of the target coil with the target current, and the real-time current is collected by a current acquisition sensor;

[0047] A generation module for generating and sending a control instruction to the power amplifier when the real-time current is not equal to the target current, so as to adjust the gain of the power amplifier, so that the real-time current of the target coil is adjusted to the target current.

[0048] In a fourth aspect, the present invention provides a computer-readable storage medium, on which computer instructions are stored, and the computer instructions are used to cause a computer to execute the coil current feedback control method according to the second aspect or any corresponding embodiment thereof.

[0049] In a fifth aspect, the present invention provides a computer program product, including computer instructions, and the computer instructions are used to cause a computer to execute the coil current feedback control method according to the second aspect or any corresponding embodiment thereof.

[0050] In the coil current feedback control system and control method provided by the embodiments of the present invention, after completing the current power amplifier gain control process, it is possible to delay for 1 second to clear the data stored in the buffer. After determining that the buffer is cleared, the next round of real-time current data reading, control calculation, and control instruction output are started, that is, the next round of power amplifier gain adjustment is started. The embodiments of the present invention ensure the smooth progress of the next round of power amplifier gain adjustment after each round of power amplifier gain adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the related art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0052] Figure 1 is a schematic structural diagram of a coil current feedback control system according to an embodiment of the present invention;

[0053] Figure 2 is a schematic diagram of the process of data acquisition and transmission according to an embodiment of the present invention;

[0054] Figure 3 is a schematic flowchart of a coil current feedback control method according to an embodiment of the present invention;

[0055] Figure 4 is a schematic diagram of a coil current feedback control process according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0057] Magnetic Particle Imaging (MPI) is an emerging medical imaging technology that uses the nonlinear magnetization response of superparamagnetic iron oxide nanoparticles in an alternating magnetic field for imaging. Compared with traditional magnetic resonance imaging and computed tomography, this technology has advantages such as higher temporal and spatial resolution, high sensitivity, and no ionizing radiation. In addition, magnetic nanoparticles are less harmful to the human body than other contrast agents such as gadolinium and iodine, and have the potential to be used as drug targeting carriers and for heat generation, making them have broad application prospects in early disease detection, vascular imaging, cancer treatment, and targeted drug delivery.

[0058] During the MPI imaging process, first, a zero magnetic field line is generated by a permanent magnet to set the magnetic field strength of the target scanning area to zero. Then, the zero magnetic field line is moved by using a drive coil and a rotating magnet, and the magnetic nanoparticles in the target area are excited by the alternating magnetic field generated by the excitation coil to produce a magnetization response signal that can be used for monitoring. After receiving these signals, the receiving coil outputs a corresponding induced voltage, which is further analyzed for imaging. In this context, electromagnetic coils are used to excite magnetic nanoparticles due to their characteristics of uniform internal magnetic field distribution and controllable magnetic field direction and magnitude. However, affected by large currents and the parasitic resistance of the coil, its temperature will rise rapidly during continuous power supply, which will further affect the matching capacitance and coil resistance, resulting in a change in the line impedance, causing the current to deviate from the target value and unable to generate a stable magnetic field. Based on the characteristic that magnetic nanoparticles are sensitive to changes in magnetic field strength in the non-saturated region, this imaging method places high requirements on the magnitude and stability of the excitation current, otherwise it will affect the quality and stability of the images formed by magnetic particle imaging.

[0059] In this embodiment, a coil current feedback control system is provided. Figure 1 It is a schematic structural diagram of the coil current feedback control system according to an embodiment of the present invention, as Figure 1 shown. The system includes:

[0060] A signal generator 101 and a power amplifier 102 for supplying power to the target coil. Among them, the signal generator 101 generates a reference signal, which is amplified by the power amplifier 102 and then provides basic power supply for the coil.

[0061] A current acquisition sensor 103 for acquiring the real-time current of the target coil.

[0062] Specifically, the current acquisition sensor 103 can be a Hall sensor. The magnetic field strength inside the coil is proportional to the magnitude of the current. The Hall sensor detects the coil current and outputs a voltage signal with a corresponding amplitude.

[0063] The processing module 104 is configured to compare the real-time current with the target current of the target coil. When the real-time current is not equal to the target current, a control instruction is sent to the power amplifier to adjust the gain of the power amplifier so that the real-time current of the target coil is adjusted to the target current. The processing module 104 may be a microprocessor.

[0064] In some optional specific embodiments, such as Figure 2 shown, the processing module 104 includes: a controller 1041, a processor 1042, and a memory 1043. The controller 1041 may be a Programmable Logic (PL) controller, and the processor 1042 may be an ARM Cortex-A9 processor. The memory 1043 may be, for example, a DDR memory (the full name is DDR SDRAM (Double Data Rate SDRAM, double data rate SDRAM)), and the DDR memory is a high-performance dynamic random access memory.

[0065] The controller includes: a cache and a data transfer control unit; the cache may be, for example, a First-In First-Out (FIFO) cache, and the data transfer control unit may be, for example, a Direct Memory Access (DMA) controller. The cache and the data transfer control unit are connected by an Advanced eXtensible Interface (AXI) bus.

[0066] The cache is configured to receive and cache the electrical signal corresponding to the real-time current;

[0067] The data transfer control unit is configured to read the electrical signal corresponding to the real-time current from the cache and write it into the memory;

[0068] The processor 1042 is configured to read the electrical signal corresponding to the real-time current from the memory and calculate the effective value of the real-time current based on the electrical signal corresponding to the real-time current;

[0069] The processor 1042 is further configured to generate the control instruction according to the deviation between the effective value of the real-time current and the target current.

[0070] In some optional specific embodiments, the processor 1042 is specifically configured to convert the digital voltage signal corresponding to the real-time current into an analog voltage signal after reading the digital voltage signal corresponding to the real-time current from the memory; obtain the maximum voltage value and the minimum voltage value of the analog voltage signal within a current change period, where the current change period is the current change period on the target coil, for example, it can be a sine period; determine the effective value of the real-time current based on the maximum voltage value, the minimum voltage value, and a conversion coefficient, where the conversion coefficient is the conversion coefficient between the input current and the output voltage of the current acquisition sensor, which is determined by the current acquisition sensor itself. Specifically, the gain adjustment period of the power amplifier can be equal to a current change period or greater than a current change period, for example, 1 second. When the gain adjustment period of the power amplifier is greater than the current change period and includes multiple current change periods, then the maximum voltage value and the minimum voltage value within one of the current change periods can be used to calculate the effective value of the real-time current.

[0071] Specifically, the digital voltage signal corresponding to the real-time current is converted into an analog voltage signal through the following formula:

[0072]

[0073] where V is the value of the analog voltage signal, Va is the value of the digital voltage signal (i.e., the voltage data stored as a digital signal), Va min and Va max are the lower limit value (e.g., 0) and the upper limit value (e.g., 255) of the digital voltage signal, and Vo min and Vo max are the values of the analog voltage signals corresponding to the lower and upper limit values of the digital voltage signal.

[0074] Among them, the process of determining the maximum voltage value and the minimum voltage value of the analog voltage signal within a current change period is as follows:

[0075] First, obtain the number of sampling points M of the analog-to-digital converter within a current change period. The number of sampling points M is determined by the sampling rate of the analog-to-digital converter.

[0076] Then, among the continuous M analog voltage signals converted from the digital voltage signal, the maximum voltage value and the minimum voltage value are obtained through a loop judgment method.

[0077] The calculation formula for the effective value of the real-time current can be:

[0078] I = α · (V max - V min )

[0079] Among them, I is the effective value of the real-time current, α is the conversion coefficient, V max and V min are the maximum voltage value and the minimum voltage value respectively.

[0080] The coil current feedback control system provided in this embodiment realizes the stable control of the coil current by dynamically adjusting the output gain of the power amplifier. It solves the current offset problem caused by the constant voltage power supply form of the signal generator and the power amplifier to supply power to the coil, and ensures the current stability when the coil works for a long time.

[0081] In some optional specific embodiments, the coil current feedback control system further includes: an analog-to-digital converter, that is, an ADC module; the analog-to-digital converter is used to receive the voltage signal corresponding to the real-time current output by the current acquisition sensor, and convert the voltage signal corresponding to the real-time current into a digital voltage signal, and transmit it to the buffer.

[0082] In some optional specific embodiments, the processing module 104 and the power amplifier 102 communicate with each other by using the Universal Asynchronous Receiver / Transmitter (UART) method. Among them, the processor is also used to configure UART communication and set parameters such as the baud rate to realize the communication between the processing module 104 and the power amplifier.

[0083] In the embodiment of the present invention, after generating the control instruction, the processing module 104 sends it to the power amplifier through UART communication, ensuring the accuracy and timeliness of the instruction transmission, and realizing the adjustment of the output gain of the power amplifier within milliseconds.

[0084] In some optional specific embodiments, the target coil is the excitation coil in the magnetic nanoparticle imaging device. That is to say, the current feedback control system provided in the embodiment of the present invention can be used for the current control of the excitation coil of the magnetic nanoparticle imaging device, and realizes the stable control of the excitation coil current by dynamically adjusting the output gain of the power amplifier, ensuring the magnetic field stability, thereby ensuring the quality and stability of the image formed by magnetic nanoparticle imaging.

[0085] In the embodiment of the present invention, by building a top-level design and programming, the ADC module is enabled to collect the voltage signal output by the Hall sensor and input it into the processing module for digital-to-analog conversion and calculation of the effective value of the current. In addition, UART communication is established and corresponding parameters are set, and instructions are sent to the program control terminal of the power amplifier through the processing module, so as to realize continuous and stable acquisition of the coil current and the communication function with the power amplifier. On this basis, a multi-functional integrated system integrating feedback control, serial port instruction generation and UART communication is realized based on the processing module. Through dynamic update of the collected data, feedback control calculation and periodic communication with the power amplifier, automatic adjustment of the gain of the power amplifier is realized, and stable and precise control of the current is realized by dynamically adjusting the input voltage of the coil, so as to meet the requirements for magnetic field stability during long-term operation of magnetic nanoparticle imaging and realize high-quality imaging.

[0086] In addition, in the embodiment of the present invention, a microprocessor can be used as the processing module, and the power amplifier device can be directly controlled by the microprocessor program. On the basis of cost savings, the system integration degree can be improved, and further, the magnetic nanoparticle imaging device can be miniaturized.

[0087] In this embodiment, a coil current feedback control method is provided, which can be used in the processing module of any of the coil current feedback control systems described in the above embodiments. Figure 3 It is a flowchart of the coil current feedback control method according to the embodiment of the present invention, as Figure 3 shown, and this process includes the following steps:

[0088] Step S301, compare the real-time current of the target coil with the target current, and the real-time current is collected by the current acquisition sensor. Specifically, as Figure 4 shown, before step S301, it is also necessary to initialize parameters such as the gain of the power amplifier and the error between the target current and the real-time current, and then start to collect and store the real-time current of the coil, read the digital voltage signal corresponding to the stored real-time current, convert it into an analog voltage signal, and calculate the corresponding effective value of the real-time current. For details, please refer to the above embodiments and will not be elaborated here.

[0089] Step S302, when the real-time current is not equal to the target current, send a control instruction to the power amplifier to adjust the gain of the power amplifier so that the real-time current of the target coil is adjusted to the target current.

[0090] In some optional implementation manners, as Figure 4 shown, the above step S302, that is, when the real-time current is not equal to the target current, send a control instruction to the power amplifier, includes:

[0091] Step S3021, calculate the error between the target current and the real-time current and the corresponding error change rate. Specifically, the error and error change rate between the target current and the real-time current can be calculated according to the following formula:

[0092] e = I tar - I

[0093]

[0094] where: e is the error; I tar is the target current value, I is the real-time current value, and ec is the error change rate.

[0095] Step S3022, use the error and the error change rate as inputs and generate a voltage control result using fuzzy logic inference.

[0096] Specifically, in step S3022, the process of using the error and the error change rate as inputs and generating a voltage control result using fuzzy logic inference includes:

[0097] Step S30221, scale the error and the error change rate to the input domain of the fuzzy controller using the pre-determined error quantization factor and error change rate quantization factor respectively. In other words, map the current error and the current error change rate to the input domain.

[0098] Specifically, the error quantization factor G e and the error change rate quantization factor G ec can be calculated by the following formula:

[0099]

[0100] where, e max and e min are the maximum and minimum values of the current error; ec max and ec min are the maximum and minimum values of the error change rate; and are the maximum and minimum values of the current error domain; and are the maximum and minimum values of the error change rate domain.

[0101] Step S30222, match the scaled error and error change rate with the pre-divided input fuzzy subsets respectively, and determine the belonging input fuzzy subsets and the corresponding first membership degrees.

[0102] Specifically, the current error and the error change rate can each have seven fuzzy subsets.

[0103] Step S30223: Based on the preset fuzzy rules, respectively determine the fuzzy output based on the input fuzzy subsets to which the error and the error change rate belong and the corresponding first membership degrees. The fuzzy output is the output fuzzy subset and the second membership degree to which the proportional and integral coefficient increments corresponding to the error belong.

[0104] Specifically, the proportional increment ΔK p The corresponding fuzzy (control) rules can be, for example, as shown in Table 1 below, and the integral coefficient increment ΔK i The corresponding fuzzy (control) rules can be, for example, as shown in Table 2 below:

[0105] Table 1

[0106]

[0107] Table 2

[0108]

[0109] Step S30224: Defuzzify the fuzzy output and convert it into the corresponding proportional and integral coefficient increments.

[0110] Specifically, the centroid method can be used to defuzzify the fuzzy output (or say defuzzify, precisify). The specific formula for defuzzification using the centroid method is:

[0111]

[0112] where u is the precise output after defuzzification; u(x) is the membership degree corresponding to the fuzzy output, that is, the second membership degree; x is the output result corresponding to the fuzzy subset, and a, b are the interval ranges of the membership function.

[0113] Of course, methods such as the maximum membership degree method and the average maximum method can also be used for defuzzification.

[0114] In addition, after defuzzification, multiply the precise output by the output quantization factor to obtain the actual proportional and integral coefficient increments of the output. The output quantization factor is as follows:

[0115]

[0116] where K pmax and K pmin are the maximum and minimum values of the output proportional coefficient increment; K imax 、K imin are the maximum and minimum values of the output integral coefficient increment; are the maximum and minimum values of the output proportional coefficient increment universe; are the maximum and minimum values of the output integral coefficient increment universe.

[0117] Step S30225: Add the said proportional and integral coefficient increments to the initial proportional and initial integral coefficients to obtain the final proportional and integral term coefficients.

[0118] Step S30226: Generate the said voltage control result based on the final proportional and integral coefficients. Specifically, the voltage control result can be calculated according to the following formula:

[0119]

[0120] where U is the voltage control result; K p and K i are the final proportional and integral term coefficients, e(t) is the current error at time t, and m, n are the time ranges.

[0121] In addition, as Figure 4 shown, the embodiment of the present invention can also perform clipping processing on the generated voltage control result to ensure it is within a reasonable range:

[0122]

[0123] In the embodiment of the present invention, a two-input and two-output fuzzy controller is built to output the proportional and integral coefficient increments.

[0124] Step S3023: Generate the said control instruction based on the control result.

[0125] Step S3024: Send the said control instruction to the power amplifier. This control instruction can be a serial port instruction, and specifically, it can be transmitted to the program-controlled end of the power amplifier through UART communication to achieve gain adjustment.

[0126] In the embodiment of the present invention, after completing the current power amplifier gain control process, it can delay for 1 second to clear the data stored in the buffer. After determining that the buffer is cleared, start the next round of real-time current data reading, control calculation, and control instruction output, that is, start the next round of power amplifier gain adjustment. The embodiment of the present invention ensures the smooth progress of the next round of power amplifier gain adjustment after each round of power amplifier gain adjustment.

[0127] The coil current feedback control method provided in this embodiment monitors the coil current through a Hall sensor, collects it by the ADC module and inputs the measured value into the processor module for numerical conversion calculation and fuzzy PI control. After performing clipping processing on the control result, a corresponding control instruction is generated, and finally, the instruction is sent to the program-controlled end of the power amplifier through UART communication to achieve automatic gain adjustment, and realizes stable control of the current by dynamically adjusting the coil input voltage, thereby meeting the requirements of magnetic nanoparticle imaging for magnetic field stability and achieving high-quality imaging.

[0128] In this embodiment, a coil current feedback control device is further provided. This device is used to implement the above-mentioned embodiments and preferred implementation manners, and those that have been described will not be repeated here. As used hereinafter, the term "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0129] This embodiment provides a coil current feedback control device, including:

[0130] A comparison module, configured to compare the real-time current of the target coil with the target current, where the real-time current is collected by a current acquisition sensor;

[0131] A generation module, configured to generate and send a control instruction to the power amplifier when the real-time current is not equal to the target current, so as to adjust the gain of the power amplifier, so that the real-time current of the target coil is adjusted to the target current.

[0132] In some optional implementation manners, the generation module includes:

[0133] A calculation unit, configured to calculate the error between the target current and the real-time current and the corresponding error change rate;

[0134] A voltage control result generation unit, configured to use fuzzy logic inference to generate a voltage control result with the error and the error change rate as inputs;

[0135] A control instruction generation unit, configured to generate the control instruction based on the voltage control result;

[0136] A sending unit, configured to send the control instruction to the power amplifier.

[0137] In some optional implementation manners, the voltage control result generation unit is specifically configured to:

[0138] Respectively scale the error and the error change rate to the input domain range of the fuzzy controller by using a pre-determined error quantization factor and error change rate quantization factor;

[0139] Match the scaled error and error change rate with the pre-divided input fuzzy subsets respectively to determine the belonging input fuzzy subsets and the corresponding first membership degrees;

[0140] Using preset fuzzy rules, respectively determine a fuzzy output based on the input fuzzy subsets to which the error and the error change rate belong and the corresponding first membership degrees, where the fuzzy output is the output fuzzy subset and the second membership degree to which the proportional and integral coefficient increments belong;

[0141] Defuzzify the fuzzy output and convert it into corresponding proportional and integral coefficient increments;

[0142] Add the proportional and integral coefficient increments to the initial proportional and initial integral coefficients to obtain the final proportional and integral coefficients;

[0143] Generate the voltage control result based on the final proportional and integral coefficients.

[0144] The further function descriptions of the above-mentioned various modules and units are the same as those in the corresponding embodiments above, and will not be elaborated here.

[0145] The coil current feedback control device in this embodiment is presented in the form of functional units. Here, the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0146] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented by downloading through a network and originally stored in a remote storage medium or a non-transitory machine-readable storage medium and will be stored in a local storage medium, so that the method described herein can be stored as such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method shown in the above embodiments is implemented.

[0147] A part of the present invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can call or provide the methods and / or technical solutions according to the present invention through the operations of the computer. Those skilled in the art should understand that the forms of existence of computer program instructions in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways for computer program instructions to be executed by a computer include, but are not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible by the computer.

[0148] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A coil current feedback control system, characterized in that: The system comprises: a signal generator and a power amplifier for powering the target coil; A current acquisition sensor, used to acquire the real-time current of the target coil; A processing module is used to compare the real-time current with the target current of the target coil, and when the real-time current is not equal to the target current, send a control instruction to the power amplifier to adjust the gain of the power amplifier so that the real-time current of the target coil is adjusted to the target current.

2. The system according to claim 1, characterized in that The target coil is an excitation coil in a magnetic nanoparticle imaging device.

3. The system according to claim 1, characterized in that The processing module includes: a controller, a processor and a memory; The controller includes: a cache and a data transmission control unit; The cache is used to receive and cache the electrical signal corresponding to the real-time current; The data transmission control unit is used to read the electrical signal corresponding to the real-time current from the cache and write it into the memory; The processor is used to read the electrical signal corresponding to the real-time current from the memory, and calculate the effective value of the real-time current based on the electrical signal corresponding to the real-time current; The processor is further configured to generate the control instruction according to a deviation between the effective value of the real-time current and the target current.

4. The system according to claim 3, characterized in that The system further includes: an analog-to-digital converter; the analog-to-digital converter is used to receive the voltage signal corresponding to the real-time current output by the current acquisition sensor, and convert the voltage signal corresponding to the real-time current into a digital voltage signal, and transmit it to the cache.

5. The system according to claim 4, characterized in that The processor is specifically configured to convert the digital voltage signal corresponding to the real-time current into an analog voltage signal after reading the digital voltage signal corresponding to the real-time current from the memory; Acquire a maximum voltage value and a minimum voltage value of the analog voltage signal within a current variation cycle, wherein the current variation cycle is a current variation cycle on the target coil; The effective value of the real-time current is determined based on the maximum voltage value, the minimum voltage value and a conversion coefficient, where the conversion coefficient is a conversion coefficient between an input current and an output voltage of the current acquisition sensor.

6. The system according to claim 5, characterized in that The digital voltage signal corresponding to the real-time current is converted into an analog voltage signal by the following formula: Where V is the analog voltage signal value, Va is the digital voltage signal value, and Va min 、Va max is the lower and upper limits of the digital voltage signal, Vo min 、Vo max It is the analog voltage signal value corresponding to the lower and upper limits of the digital voltage signal.

7. The system according to claim 4, characterized in that The processing module communicates with the power amplifier using a universal asynchronous receiver-transmitter.

8. A coil current feedback control method, characterized in that: A processing module applied to a coil current feedback control system according to any one of claims 1 to 5, the method comprising: comparing the real-time current of the target coil with the target current, wherein the real-time current is collected by a current collection sensor; When the real-time current is not equal to the target current, a control instruction is generated and sent to the power amplifier to adjust the gain of the power amplifier so that the real-time current of the target coil is adjusted to the target current.

9. The method according to claim 8, characterized in that When the real-time current is not equal to the target current, generating and sending a control instruction to the power amplifier comprises: Calculating the error between the target current and the real-time current and the corresponding error change rate; Taking the error and the error change rate as input, using fuzzy logic reasoning to generate a voltage control result; generating the control instruction based on the voltage control result; The control instruction is sent to the power amplifier.

10. The method according to claim 9, characterized in that The method of using the error and the error change rate as input and using fuzzy logic reasoning to generate a voltage control result includes: The error and the error change rate are scaled to within the input domain of the fuzzy controller using a predetermined error quantization factor and an error change rate quantization factor respectively; Matching the scaled error and the error change rate with the pre-divided input fuzzy subsets respectively, and determining the input fuzzy subsets and the corresponding first membership degree; Determine a fuzzy output based on the input fuzzy subsets to which the error and the error change rate belong and the corresponding first membership by using a preset fuzzy rule, wherein the fuzzy output is the output fuzzy subset and the second membership to which the proportional and integral coefficient increments belong; The fuzzy output is clarified and converted into corresponding proportional and integral coefficient increments; Adding the proportional and integral coefficient increments to the initial proportional and integral coefficients to obtain final proportional and integral coefficients; Based on the final proportional and integral coefficients, the voltage control result is generated.

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