Power output method, device and system based on filament current and magnetic field current

Abstract

The application belongs to the technical field of microwave sources, and provides a power output method, device and system based on filament current and magnetic field current, wherein the method comprises executing a plurality of periods, the nth period comprising the following steps: acquiring and executing a control strategy, then collecting the real-time power of the magnetron, if the deviation value of the real-time power of the magnetron and the target power is within the set range, then all the n periods are completed, otherwise the (n+1)th period is entered, n>=1; after all the periods are completed, if the deviation value of the real-time power and the target power is greater than the set value and the duration exceeds the set time, then the power output method is re-executed. The method of the application adopts a filament current control strategy, a magnetic field current control strategy and a power control strategy, and the three strategies work together, and the organic integration of the multiple strategies makes the operation of the magnetron more stable and adaptive.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave sources, and particularly relates to a power output method, device and system based on filament current and magnetic field current. BACKGROUND

[0002] In the industrial microwave application scenario, the power control of the magnetron by the microwave generator still has many obvious defects, mainly in the following aspects:

[0003] Firstly, the single problem of filament control. If the filament current is too low, the cathode temperature will be insufficient, resulting in the attenuation of electron emission energy, causing the power to drop instantaneously. In severe cases, it may also cause sparking, frequency fluctuation and other phenomena, not only shortening the service life of the magnetron, but even directly causing the device to be damaged. Conversely, if the filament current is too high, the cathode temperature will be too high, causing excessive electron emission, resulting in power attenuation in the long-term working state and shortening the service life by nearly half.

[0004] Secondly, the limitation caused by magnetic field solidification. Ordinary magnetrons use permanent magnet design, and the magnetic field strength cannot be adjusted. Although industrial magnetrons use electromagnets, there is a lack of coordinated control strategy with the emission characteristics of the filament, which easily leads to the instability of the electron cloud (such as the misadjustment of the spoke-like distribution).

[0005] In addition, there is an inherent contradiction between life and power: filament overheating will accelerate cathode aging, and excessive magnetic field strength may cause electron back bombardment and cause extinguishing, which all restrict the stable operation of the magnetron. SUMMARY

[0006] In order to solve the problems in the background art, the application proposes a power output method, device and system based on filament current and magnetic field current.

[0007] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0008] The power output method based on filament current and magnetic field current is executed for a plurality of periods, and the nth period includes the following steps:

[0009] Obtaining and executing a control strategy, the control strategy including a filament current control strategy, a magnetic field current control strategy and a power control strategy;

[0010] After executing the control strategy, the real-time power of the magnetron is collected, and if the deviation value of the real-time power of the magnetron and the target power is within the set range, then all n periods are completed, otherwise the (n+1)th period is entered, n≥1;

[0011] After all the periods are completed, if the deviation value of the real-time power and the target power is greater than the set value and the duration exceeds the set time, then the power output method is re-executed.

[0012] Further, the obtaining and executing the control strategy further comprises a preparation step within or outside the cycle, the preparation step comprises;

[0013] Obtaining the target power of the magnetron;

[0014] Determining the power interval of the magnetron based on the target power, and determining the corresponding control strategy according to the power interval.

[0015] Further, the determination of the power interval of the magnetron based on the target power comprises the following steps:

[0016] Comparing the target power with the rated power of the magnetron to determine the power interval of the magnetron.

[0017] Further, the power interval comprises a low power segment and a high power segment, and the corresponding filament current control strategy is executed based on the power interval, which comprises executing a control parameter calling instruction according to the power interval to generate a control strategy corresponding to each power interval;

[0018] The control parameter comprises a correction factor constant K 3, filament current index a , magnetic field intensity index b , magnetron parameter K , initial magnetic field current reference value, initial filament current reference value, PID parameter and decoupling compensation coefficient.

[0019] Further, the power interval comprises a low power segment, a medium power segment and a high power segment;

[0020] The control strategy corresponding to the low power segment comprises: setting the magnetic field current to 37%~42% of the rated magnetic field current; executing the corresponding filament current control strategy and power control strategy; the control strategy corresponding to the medium power segment comprises: executing the corresponding filament current control strategy, magnetic field current control strategy and power control strategy; the control strategy corresponding to the high power segment comprises: setting the value of the filament current to be less than 20% of the rated filament current; executing the corresponding magnetic field current control strategy and power control strategy.

[0021] Further, the execution of the filament current control strategy comprises the following steps:

[0022] Generating a reference value of the filament current;

[0023] Collecting the real-time filament current of the magnetron and comparing it with the reference value of the filament current;

[0024] Outputting a first control instruction based on the comparison result to adjust the filament current of the magnetron, forming a closed-loop control of the filament current.

[0025] Further, the reference value of the filament current satisfies:

[0026] ;

[0027] wherein, represents the reference value of the filament current; represents the reference value of the magnetic field current of the previous period; is the target power K 3 is a correction factor constant; a is the filament current index; b is the magnetic field strength index; K is the magnetron parameter, which is a constant.

[0028] Further, the magnetic field current control strategy is executed, including the following steps:

[0029] generating the reference value of the magnetic field current;

[0030] collecting the real-time magnetic field current of the magnetron and comparing it with the reference value of the magnetic field current;

[0031] outputting a second control instruction to adjust the magnetic field current of the magnetron based on the comparison result, forming a closed-loop control of the magnetic field current.

[0032] Further, the reference value of the magnetic field current satisfies:

[0033] ;

[0034] wherein, represents the reference value of the magnetic field current; represents the reference value of the filament current of the previous period; is the target power; K 3 is a correction factor constant; a is the filament current index; b is the magnetic field strength index; K is the magnetron parameter, which is a constant.

[0035] Further, the power control strategy is executed, including the following steps:

[0036] After the filament current control strategy and / or the magnetic field current control strategy are executed, the real-time power of the magnetron is collected and compared with the target power;

[0037] outputting the correction amount of the filament current and the magnetic field current based on the comparison result;

[0038] inputting the real-time power of the magnetron, the correction amount of the filament current and the correction amount of the magnetic field current to the next period.

[0039] Further, when the target power is greater than 0 and less than or equal to 30% of the rated power, the magnetron is in a low power section; when the target power is greater than 30% and less than or equal to 70% of the rated power, the magnetron is in a medium power section; when the target power is greater than 70% and less than or equal to 100% of the rated power, the magnetron is in a high power section.

[0040] The application provides a power output device based on filament current and magnetic field current, the device comprising a magnetron and a microwave power supply for powering the magnetron, and the device further comprising a processor for executing the method described above.

[0041] The application also provides a power output system based on filament current and magnetic field current, comprising:

[0042] The first processing unit is configured to obtain a target power of the magnetron, determine a power interval in which the magnetron is located based on the target power, and determine that all n cycles are completed when the real-time power of the magnetron is within the set range, otherwise the first processing unit executes the next cycle.

[0043] The control unit is configured to execute a corresponding control strategy based on the power interval, and the control strategy comprises a filament current control strategy, a magnetic field current control strategy and a power control strategy.

[0044] The power sensor is configured to collect the real-time power of the magnetron after the control strategy is executed.

[0045] The start unit is configured to restart the first processing unit, the control unit and the power sensor to execute the corresponding strategy if the deviation between the real-time power and the target power is greater than a set value and the duration exceeds a set time after all cycles are completed.

[0046] Further, the control unit comprises:

[0047] The filament current controller is configured to generate a reference value of the filament current and collect the real-time filament current of the magnetron.

[0048] The filament loop PID regulator is configured to compare the real-time filament current of the magnetron with the reference value of the filament current, output a first control instruction based on the comparison result to adjust the filament current of the magnetron, and form a closed-loop control of the filament current.

[0049] The magnetic field current controller is configured to generate a reference value of the magnetic field current and collect the real-time magnetic field current of the magnetron.

[0050] The magnetic field loop PID regulator is configured to compare the real-time magnetic field current of the magnetron with the reference value of the magnetic field current, output a second control instruction based on the comparison result to adjust the magnetic field current of the magnetron, and form a closed-loop control of the magnetic field current.

[0051] And, a power PID regulator is used to compare the real-time power of the magnetron with the target power after the filament current control strategy and / or the magnetic field current control strategy is executed, and output the correction amount of the filament current and the magnetic field current based on the comparison result, and input the real-time power of the magnetron, the correction amount of the filament current and the correction amount of the magnetic field current to the next cycle.

[0052] The beneficial effects of the present application are as follows:

[0053] The method of the present application adopts the filament current control strategy, the magnetic field current control strategy and the power control strategy, and the three strategies work together, on the one hand, by accurately grasping the dynamic correlation between the filament current and the electron emission density, the limitation of traditional filament control is broken, and the electron emission state can be flexibly adjusted according to actual needs, on the other hand, the dynamic regulation of the magnetic field is realized by means of the corresponding relationship between the magnetic field strength and the magnetic field current, which not only solves the problem of permanent magnet magnetron magnetic field solidification, but also makes up for the defect that the magnetic field and the filament emission characteristics lack cooperation in industrial magnetrons, the power control strategy can feedback the results of the filament current control strategy and the magnetic field current control strategy, and the correction amount of the next cycle can be calculated, the organic integration of multiple strategies makes the operation of the magnetron more stable and adaptable.

[0054] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and achieved by the structure as indicated in the description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0056] Figure 1 The first embodiment of the power output method based on the filament current and the magnetic field current of the present application is shown;

[0057] Figure 2 The second embodiment of the power output method based on the filament current and the magnetic field current of the present application is shown;

[0058] Figure 3 The structure block diagram of the power output system based on the filament current and the magnetic field current of the present application is shown. DETAILED DESCRIPTION

[0059] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0060] The power output method based on the filament current and the magnetic field current in the present application is executed for several cycles, and the nth cycle includes the following steps:

[0061] A control strategy is acquired and executed, and the control strategy includes a filament current control strategy, a magnetic field current control strategy and a power control strategy.

[0062] After the control strategy is executed, the real-time power of the magnetron is collected, if the deviation value of the real-time power of the magnetron and the target power is within the set range, then the n cycles are all completed, otherwise, the (n+1)th cycle is entered, and n≥1.

[0063] After all the cycles are completed, if the deviation value of the real-time power and the target power is greater than the set value and the duration exceeds the set time, then the power output method is re-executed.

[0064] Before the several cycles are executed or in each cycle, a preparation step can also be included. The preparation step includes:

[0065] The target power of the magnetron is acquired; based on the target power, the power interval in which the magnetron is located is determined, and the corresponding control strategy is determined according to the power interval.

[0066] Exemplarily, after the target power of the magnetron is acquired, the target power can be compared with the rated power of the magnetron to determine the power interval in which the magnetron is located. Then, the control parameter calling instruction is executed according to the power interval, so as to generate the control strategy corresponding to each power interval.

[0067] Specifically, the power interval divided in the embodiments of the present application has at least two. The control parameters include the correction factor constant K 3, the filament current index a , the magnetic field strength index b , the magnetron parameter K , the initial magnetic field current reference value, the initial filament current reference value, the PID parameter and the decoupling compensation coefficient. It can be understood that different power intervals can have different control parameters.

[0068] It is understood that a power range is a power segment designed for the adjustable range of rated power. The magnetron operates differently at different output powers. This application optimizes the control of the magnetron by dividing the power range into different power ranges (i.e., power segments in the following text) and using corresponding control strategies for each power range. For example, three power ranges can be set: a low-power range, a medium-power range, and a high-power range. It is also understood that different numbers of power ranges can be designed for different magnetrons. The number of power ranges can be two (e.g., only divided into high-power and low-power ranges), or more than three (e.g., in addition to the high-power and low-power ranges, at least two medium-power ranges are set).

[0069] Each power range / power segment corresponds to a different control strategy. In this application, the control strategy for each power range is specifically: at least one of the filament current control strategy and the magnetic field current control strategy; and a power control strategy.

[0070] In the embodiments of this application:

[0071] The control strategy for the low-power range can be: set the magnetic field current to a fixed value, for example, it can be set to 37%~42% of the rated magnetic field current; and execute the corresponding filament current control strategy and power control strategy.

[0072] The control strategies corresponding to the low power range can also be: executing the corresponding filament current control strategy, magnetic field current control strategy, and power control strategy.

[0073] The control strategies corresponding to the medium power range can be: executing the corresponding filament current control strategy, magnetic field current control strategy, and power control strategy.

[0074] The control strategy for the high-power range can be: set the filament current to a fixed value, for example, it can be set to be less than 20% of the rated filament current, and execute the corresponding magnetic field current control strategy and power control strategy.

[0075] The control strategy for the high-power segment can also be: to execute the corresponding filament current control strategy, magnetic field current control strategy, and power control strategy.

[0076] The power output method of this application will be described in detail below with reference to the specific embodiments shown in the accompanying drawings.

[0077] like Figure 1 The diagram illustrates a power output method based on filament current and magnetic field current, which executes several cycles. The nth cycle includes the following steps:

[0078] S1: Obtain the target power of the magnetron.

[0079] S2: judging the power interval of the magnetron based on the target power.

[0080] S3: executing the corresponding control strategy based on the power interval, the control strategy including filament current control strategy, magnetic field current control strategy and power control strategy.

[0081] S4: after executing the control strategy, collecting the real-time power of the magnetron, if it is in the set range, then all the n cycles (this cycle) are completed, otherwise, entering the next cycle, n is greater than or equal to 1.

[0082] S5: after all the cycles are completed, if the deviation between the real-time power and the target power is greater than the set value, and the duration exceeds the set time, then re-executing the power output method.

[0083] It should be noted that the magnetron is a device for generating electrons, the filament is a part of the magnetron, the magnetic field current is for the electromagnet, and the electromagnet is a device for generating a magnetic field, which is usually installed outside the tube body of the magnetron; by controlling the filament current input to the magnetron and the magnetic field current input to the electromagnet, the electron emission of the magnetron is controlled. The magnetron in the embodiment includes the whole including the tube body and the electromagnet, and the target power is understood as the target value of the output power of the magnetron.

[0084] In order to help understand the relationship between the parameters of the magnetron, in S1-S4, the filament current ( I f ) is the electron emission density control variable, the magnetic field current ( I m ) is the electron cyclotron motion control variable, and by establishing the nonlinear mapping relationship between the two and the output power, the precise control of the power output is realized. Therefore, when executing S1-S4, the nonlinear mapping relationship between the filament current and the electron emission density, the functional relationship between the magnetic field strength and the magnetic field current, and the relationship between the output power of the magnetron and the electron emission density and the magnetic field current need to be understood.

[0085] 1) Mapping relationship between electron emission density and filament current

[0086] Filament temperature T satisfies Joule's law:

[0087] ; (1)

[0088] In the formula, K 1 is the thermal conversion coefficient (0.85-0.92), R f is the filament resistance (0.023-0.15 Ω at 25 °C), t is the filament conduction time (s), K 2 is the heat dissipation coefficient (0.02-0.05),T 0 is the ambient temperature (℃); I f I represents the filament current (A).

[0089] electron emission density J According to Richardson-Dushman equation:

[0090] ; (2)

[0091] In the formula, A K is Richardson constant (take 32A / (cm 2. K 2 ), φ is the work function (4.5eV for tungsten filament), K b B is Boltzmann constant (1.380649×10 23 J / K); T 阴极 I represents the absolute temperature of the filament (cathode), T K is the filament temperature (℃).

[0092] 2) Magnetic field strength and magnetic field current relationship

[0093] ; (3)

[0094] In the formula, K 3 is the correction factor constant, μ0 is the vacuum permeability (4π×10 7 H / m), N N is the total number of turns of the coil, I m I is the magnetic field current, unit A; L L is the length of the coil, unit meter.

[0095] 3) The relationship between the filament current and the magnetic field current cooperative power output, that is, the relationship between the output power of the magnetron and the electron emission density and the magnetic field current

[0096] ; (4)

[0097] In the formula, K 4 is the correction factor constant (take 0.002~0.01), J J is the electron emission density of the magnetron, unit is A / m 2 ; B B is the magnetic field strength, unit A / m; V a V is the anode voltage, unit v; η is the conversion efficiency (usually the conversion efficiency of the magnetron is 0.6~0.9); PThe output power of the magnetron is W, and the calculation result thereof in an ideal state can be equal to the target power.

[0098] For S1, in combination with the content of Figure 1 , it can be known that the power output method based on the filament current and the magnetic field current generally contains n periods, and there is a certain difference between S1 of the first period and S1 of the subsequent periods. Specifically, the first period needs to set a target power according to the demand, and the target power can be calculated by formula (4). Exemplarily, after one period ends, it is needed to judge whether the deviation between the real-time power and the target power is within a predetermined range (exemplarily, the predetermined range can be set to 3% Pn , Pn % of the rated power). If this condition is met, it indicates that the entire process is completed.

[0099] In S2, the power interval of the magnetron is judged based on the target power, including the following steps:

[0100] S201: The target power is compared with the rated power of the magnetron to determine the power interval of the magnetron.

[0101] S202: When the target power is greater than 0 and less than or equal to 30% of the rated power, the magnetron is in a low-power segment; when the target power is greater than 30% and less than or equal to 70% of the rated power, the magnetron is in a medium-power segment; and when the target power is greater than 70% and less than or equal to 100% of the rated power, the magnetron is in a high-power segment.

[0102] It needs to be further explained that the adjustment modes of the filament current and the magnetic field current corresponding to each power segment in S2 are different, and the embodiment does not specifically limit them. Exemplarily:

[0103] When in the low-power segment: the magnetic field current is fixed at 37%-42% of the rated value, the corresponding filament current control strategy and power control strategy are executed, including adjusting the filament current to dominate the power output, wherein a=2.3 and b=0.6 (a is the filament current index, and b is the magnetic field intensity index);

[0104] When in the medium-power segment: the corresponding filament current control strategy, magnetic field current control strategy and power control strategy are executed, including the coordinated adjustment of the filament current and the magnetic field current, wherein a=2.0 and b=0.9;

[0105] When in the high-power segment: the filament current is fixed at 0-20% of the rated value, the corresponding magnetic field current control strategy and power control strategy are executed, including adjusting the magnetic field current to dominate the power output, wherein a=1.8 and b=1.2.

[0106] In S3, the corresponding filament current control strategy is executed based on the power interval, including executing a control parameter call instruction according to the power interval to generate a control strategy corresponding to each power interval. The control parameters include a correction factor constant K 3, a filament current index a , a magnetic field strength index b , a magnetron parameter K , an initial magnetic field current reference value, an initial filament current reference value, a PID parameter, and a decoupling compensation coefficient

[0107] Exemplarily, in the medium power segment, the filament current control strategy and the magnetic field current control strategy can be synchronized, wherein the filament current control strategy includes the following steps when executed:

[0108] S301a: generating a reference value of the filament current.

[0109] S302a: collecting the real-time filament current of the magnetron and comparing it with the reference value of the filament current.

[0110] S303a: outputting a first control instruction based on the comparison result to adjust the filament current of the magnetron, forming a closed-loop control of the filament current.

[0111] It needs to be further explained that the filament current controller is required to execute the filament current control strategy, which is used to collect the filament current and control the electron emission density. The temperature control of the magnetron cathode can be realized through the filament current control, reducing the influence of temperature on the anode current and output power.

[0112] Specifically, in step S301a, the reference value of the filament current satisfies:

[0113] ; (5)

[0114] In the formula, represents the reference value of the filament current; represents the reference value of the magnetic field current of the last period; is the target power K 3 is a correction factor constant; a is a filament current index; b is a magnetic field strength index; K is a magnetron parameter, which is a constant.

[0115] In S3, the magnetic field current control strategy includes the following steps when executed:

[0116] S301b: generating a reference value of the magnetic field current.

[0117] S302b: collecting the real-time magnetic field current of the magnetron and comparing it with the reference value of the magnetic field current.

[0118] S303b: outputting a second control instruction to adjust the magnetic field current of the magnetron based on the comparison result, to form a closed-loop control of the magnetic field current.

[0119] It should be noted that the magnetic field current control strategy needs to use a magnetic field current controller, which can collect the magnetic field current and ensure that the electrons can stably maintain the trochoidal motion state and keep synchronization with the microwave field through accurate regulation of the electron motion trajectory. This control mechanism can effectively reduce the influence of two adverse situations: one is that when the magnetic field is too weak, the electrons will directly reach the anode and cannot form oscillation; the other is that when the magnetic field is too strong, the electrons will return to the cathode, causing the system to extinguish.

[0120] Specifically, in step S301b, the reference value of the magnetic field current satisfies:

[0121] ; (6)

[0122] In the formula, represents the reference value of the magnetic field current; represents the reference value of the filament current in the last period; is the target power; K 3 is a correction factor constant; a is the filament current index; b is the magnetic field strength index; K is the magnetron parameter, which is a constant.

[0123] In an embodiment of the present application, the filament current index a and the magnetic field strength index b in formula (5) and formula (6) can be obtained by fitting a plurality of experimental data. The experimental steps are as follows: adjust different target powers to perform a plurality of power output adjustment experiments, and record the measured values of the a and b parameters after the system stabilizes. The least squares method is used for fitting calculation. See Table 1 for details.

[0124] Table 1

[0125]

[0126] Through Table 1, the least squares method is used for fitting: a = 2.31-0.0052xP(±0.03), b = 0.61+0.0058x (±0.03).

[0127] In addition, as shown in Table 1, the error between the calculated value of the fitting formula and the experimentally measured value is all ≤±0.03, which meets the fitting accuracy requirement in the document. The a value of the low-power segment is relatively high (2.29-2.30), indicating that the filament current has a more significant impact on the power. Therefore, in an embodiment of the present application, the control strategy adopted in the low-power segment is to set the magnetic field current as a fixed value, while the corresponding filament current control strategy and power control strategy are executed. The a value of the high-power segment is reduced and the b value is increased, which reflects the characteristics of the magnetic field current dominating the power regulation. Therefore, in an embodiment of the present application, the control strategy adopted in the high-power segment is to set the filament current as a fixed value, while the corresponding magnetic field current control strategy and power control strategy are executed.

[0128] In the present application, the values of the filament current index a and the magnetic field strength index b corresponding to various power segments are pre-stored in the system through multiple tests in the early stage, so as to be subsequently called by program instructions.

[0129] In S3, after the filament current control strategy and / or the magnetic field current control strategy are completed, the power control strategy can be executed, including the following steps:

[0130] S304: Collecting the real-time power of the magnetron and comparing it with the target power; S305: Outputting the correction amount of the filament current and the magnetic field current based on the comparison result; S306: Inputting the real-time power of the magnetron, the correction amount of the filament current, and the correction amount of the magnetic field current into the next cycle.

[0131] It should be noted that in S306, since there can be a certain deviation between the real-time power and the target power in the present cycle, the deviation can correspond to the correction amount of the filament current and the magnetic field current, which is used in the control and regulation of the filament current and the magnetic field current in the next cycle.

[0132] In S4, the real-time power of the magnetron needs to be compared with the target power. If the deviation value between the real-time power and the target power is within the set range, the process ends and does not enter the next cycle. The set range is not specifically limited in the present embodiment. For example, the deviation value between the real-time power and the target power ≤3% Pn ( Pn of the rated power can be considered as that n cycles are all completed. Pn Pn Pn

[0133] ​​​In summary, the power output method based on filament current and magnetic field current collects and monitors three quantities—filament current, magnetic field current, and output power—according to the characteristics of the magnetron. At the same time, PID regulation is applied to the filament current and magnetic field circuits to ensure that the final real-time (output) power meets the preset target power.

[0134] Taking the first cycle of a certain experiment as an example, the process is as follows:

[0135] Set target power: User inputs target power (e.g., 1.8kW), the system obtains the target power.

[0136] Interval judgment: =30% Pn ( Pn Assuming the rated power... Pn =6kW), the power range is determined to be the low power range, and the control strategy is determined to be the control strategy corresponding to the low power range.

[0137] Initialization: Load magnetron parameters ( K =0.476, a=2.3, b=0.6), set the initial filament current. I f0 =32A, initial magnetic field current I m0 =0.74A.

[0138] Solution output: With the fixed magnetic field current at 37% of the rated value (for example, the rated magnetic field current is 2A), adjust the filament current to dominate the power output; calculate the reference value of the magnetic field current. ≈0.8A, reference value for filament current ≈9.9A.

[0139] Closed-loop regulation:

[0140] Filament current control strategy: Compare the filament current of this cycle with the filament current reference value ( + ΔI f1 The deviation is then processed by the filament ring PID controller to output the PWM duty cycle.

[0141] Magnetic field current control strategy: Compare the deviation between the magnetic field current of this cycle and the magnetic field current reference value, and then output the PWM duty cycle through the magnetic field loop PID regulator.

[0142] Power control strategy: Calculate the deviation between the real-time (output) power and the target power for the current cycle, and output the filament current based on the deviation. I f Correction amount I f1Output magnetic field current based on deviation I m Correction amount I m1 .

[0143] In S5, the control and regulation process ends after all cycles have been completed. This means the magnetron has now entered normal operating mode and is outputting the target power.

[0144] If the deviation between the real-time power and the target power of the magnetron is detected to be greater than 5% of the rated power and the duration exceeds 200ms, then S1-S5 need to be rerun.

[0145] like Figure 2 As shown, another optional implementation of the power output method based on filament current and magnetic field current is given, wherein steps A1 and A2 do not participate in the cycle, as follows:

[0146] A1: Obtain the target power of the magnetron.

[0147] A2: Determine the power range of the magnetron based on the target power.

[0148] A3: Execute several cycles. The nth cycle includes the following steps:

[0149] A301: Executes corresponding control strategies based on the power range. The control strategies include filament current control strategy, magnetic field current control strategy, and power control strategy.

[0150] A302: After executing the control strategy, the real-time power of the magnetron is collected. If it is within the set range, all n cycles are completed; otherwise, the (n+1)th cycle is entered, where n is greater than or equal to 1.

[0151] A4: After all cycles are completed, the adjustment and control process stops, and the magnetron outputs power according to the target power. If the deviation between the real-time power and the target power is detected to be greater than the set value and the duration exceeds the set time, the adjustment and control process is restarted, and the power output method is executed.

[0152] It should be noted that Figure 2 Methods and Figure 1 The difference lies in the starting point of the cycle, among which Figure 1 Steps S1 and S2 participate within the cycle. Figure 2 Steps A1 and A2 are outside the cycle, for Figure 2 In terms of the method, it can be used in application scenarios where the target power remains constant. Whether steps A1 and A2 participate in the loop does not affect the final output result, and its running result is the same as... Figure 1 The methods are the same. The device and system can automatically modify the cyclic correlation settings of the two methods according to actual needs.

[0153] In some cases, the target power can change during the process of adjusting the output power of the magnetron based on the filament current and the magnetic field current. For example, the user changes the target power value. In this case, the method steps shown in FIG. 1 can be selected, i.e., the preparation steps (S1, S2) are performed once in each cycle, so that the target power can be timely responded after the target power changes. Figure 1

[0154] In other cases, the target power is fixed after the target power is input. For example, the target power value is locked after the target power is input until the cycle is completed. In this case, the method steps shown in FIG. 2 can be selected, i.e., the preparation step is performed once before the cycle starts, and after the power interval where the target power is located is determined, the corresponding control strategy is directly started to be executed until the power output meets the target power requirement. In this case, the process steps in the cycle are simplified, and the efficiency is higher. Figure 2

[0155] In particular, when the value of the target power is near the boundary point of two power intervals, the control strategy corresponding to the adjacent two power intervals can be actually taken to achieve the output adjustment of the target power. For the case where the value of the target power is near the boundary point of two power intervals (near can be ±5% Pn ), if the control strategy corresponding to the power interval where the target power is located cannot achieve the output adjustment of the target power after a predetermined time (for example, 200 ms), the control strategy corresponding to the adjacent power interval is switched to perform the power output adjustment until the adjustment is completed.

[0156] The second aspect of the present application also proposes a power output device based on a filament current and a magnetic field current, which comprises a magnetron and a microwave power supply for supplying power to the magnetron, and further comprises a processor which can execute the aforementioned power output method based on a filament current and a magnetic field current. Specifically, the device can be a microwave generator. As a device for generating microwaves, the microwave generator can be applied to a microwave plasma device. The plasma cleaning machine uses plasma to process the surface of a material, removes dirt, and increases activity, and is suitable for semiconductor microelectronics, medical treatment, optics, automobiles, and other fields, and has the advantages of high efficiency, environmental protection, and selectivity. It can also be applied to the field of environmental protection, for example, a microwave plasma torch can be used to process various solid waste (urban household garbage, industrial and hazardous solid waste, medical and electronic hazardous waste, sewage sludge, and smelting slag and mining tailings, etc.). A high-power industrial microwave generator device can also be applied to an MPCVD device for preparing artificial diamonds and carbon nanotube materials.

[0157] As shown in FIG. 3, the power output device based on a filament current and a magnetic field current can be a microwave generator. Figure 3 ​​As shown, it is a power output system based on filament current and magnetic field current, which is used in the power output method based on filament current and magnetic field current in the application, comprising:

[0158] The first processing unit is configured to obtain a target power of the magnetron, determine a power interval in which the magnetron is located based on the target power, and determine that all n cycles are completed when the real-time power of the magnetron is within the set range, otherwise the first processing unit executes the next cycle.

[0159] The control unit is configured to execute a corresponding control strategy based on the power interval, and the control strategy comprises a filament current control strategy, a magnetic field current control strategy and a power control strategy. Specifically, the control unit generates reference signals of the filament current and the magnetic field current in combination with the output of the power PID regulator (power loop feedback). The filament current reference signal is input into the filament loop PID regulator, compared with the feedback value collected by the filament current, and outputs a control signal to the filament current controller to adjust the filament current, thereby forming a filament current closed loop. The magnetic field current reference signal is input into the magnetic field loop PID regulator and the magnetic field current controller in the same way, thereby forming a magnetic field current closed loop.

[0160] The power sensor is configured to collect the real-time power of the magnetron after the control strategy is executed. Specifically, the output power of the magnetron is continuously collected and fed back to the power PID regulator to correct the reference signal of the power loop. The closed-loop adaptive control module adaptively adjusts the PID parameters or control algorithm (such as switching from fuzzy PID to sliding mode control) according to real-time data such as power deviation and current fluctuation.

[0161] The starting unit is configured to restart the first processing unit, the control unit and the power sensor to execute the corresponding strategy if the deviation between the real-time power and the target power is greater than a set value and the duration exceeds a set time after all cycles are completed.

[0162] Further, the control unit comprises a filament current controller configured to generate a reference value of the filament current, and a real-time filament current of the magnetron is collected. The filament loop PID regulator is configured to compare the real-time filament current of the magnetron with the reference value of the filament current, output a first control instruction to adjust the filament current of the magnetron, and form a closed-loop control of the filament current.

[0163] Further, the control unit comprises a magnetic field current controller configured to generate a reference value of the magnetic field current, and a real-time magnetic field current of the magnetron is collected. The magnetic field loop PID regulator is configured to compare the real-time magnetic field current of the magnetron with the reference value of the magnetic field current, output a second control instruction based on the comparison result to adjust the magnetic field current of the magnetron, and form a closed-loop control of the magnetic field current.

[0164] Further, the control unit comprises:

[0165] a power PID regulator, for comparing the real-time power of the magnetron with the target power after the completion of the filament current control strategy and / or the magnetic field current control strategy, and outputting a correction amount of the filament current and the magnetic field current based on the comparison result, and inputting the real-time power of the magnetron, the correction amount of the filament current and the correction amount of the magnetic field current to the next cycle.

[0166] For the system embodiment, the hardware employed in the system is not specifically limited, and exemplary:

[0167] 1) The function of the first processing unit can be realized based on an STM32F103 microprocessor (MCU for short). The universal synchronous / asynchronous transceiver (USART) is used to establish communication with the filament current controller and the magnetic field current controller, so as to realize control signal output. At the same time, the 12-bit ADC interface is used to collect sensor group signals, and the sampling frequency is set to 10 kHz, so as to ensure data real-time performance. Except for the power sensor, all other control and collection in the system block diagram are completed by the MCU.

[0168] The system MCU receives the set target power, reads the feedback value of the power sensor (or the output power setting value of the microwave power supply) to determine the real-time power. Based on the target power, the power interval is judged by comparing with the 30%Pn and 70%Pn threshold values, to determine the current interval (low power segment, medium power segment, high power segment), and the corresponding power algorithm module is selected. The low, medium and high power algorithm modules adjust the relevant control parameters (such as PID parameter adjustment instructions, decoupling compensation coefficients, etc.) according to the interval characteristics, to generate the control strategy of the closed-loop adaptive control module for each interval.

[0169] 2) The filament current controller adopts a full-bridge phase-shift PWM topology. The PWM control signal (frequency 20 kHz) output by the MCU is input to the drive chip after being isolated by the optocoupler (model TLP250), to drive the MOSFET full-bridge circuit, so as to realize 0~10V output voltage regulation.

[0170] 3) The filament current signal collected by the Hall current sensor is converted into a voltage signal and fed back to the MCU, so as to obtain the real-time filament current.

[0171] 4) The linear amplification circuit is adopted. The MCU outputs a 0~3.3V control signal through the DAC (digital-to-analog converter), which drives the electromagnetic coil after amplification, so as to realize 0~2A magnetic field current regulation. The magnetic field voltage signal collected by the sampling resistor is filtered and fed back to the MCU, so as to obtain the real-time magnetic field current.

[0172] 5) The real-time output power collected by the power sensor is fed back to the MCU, so as to realize 0~10kW power measurement.

[0173] Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood that modifications can be made to the foregoing embodiments, or additional implementations can be implemented, without departing from the spirit and scope of the inventive subject matter. Accordingly, the present application is not limited to the implementations described herein, but is intended to be defined by the claims set forth below, and equivalents thereof.

Claims

1. A method of power output based on filament current and magnetic field current, characterized in that, performing a plurality of cycles, the nth cycle comprising the following steps: acquiring and executing a control strategy, the control strategy comprising a filament current control strategy, a magnetic field current control strategy, and a power control strategy; performing the filament current control strategy, comprising: generating a reference value of the filament current; collecting a real-time filament current of the magnetron and comparing it with the reference value of the filament current; outputting a first control instruction to adjust the filament current of the magnetron based on the comparison result, forming a closed-loop control of the filament current; performing the magnetic field current control strategy, comprising: generating a reference value of the magnetic field current; collecting a real-time magnetic field current of the magnetron and comparing it with the reference value of the magnetic field current; outputting a second control instruction to adjust the magnetic field current of the magnetron based on the comparison result, forming a closed-loop control of the magnetic field current; performing the power control strategy, comprising: after the filament current control strategy and / or the magnetic field current control strategy are executed, collecting a real-time power of the magnetron and comparing it with a target power; outputting a correction amount of the filament current and the magnetic field current based on the comparison result; inputting the real-time power of the magnetron, the correction amount of the filament current, and the correction amount of the magnetic field current into the next cycle; after the control strategy is executed, collecting a real-time power of the magnetron, if the deviation value of the real-time power of the magnetron and the target power is within a set range, then all the n cycles are completed, otherwise, entering the (n+1)th cycle, n≥1; after all the cycles are completed, if the deviation value of the real-time power and the target power is greater than a set value and the duration exceeds a set time, then the power output method is re-executed.

2. The filament current and magnetic field current based power output method of claim 1, wherein, Before acquiring and executing the control strategy, a preparation step within or outside the cycle is further included, the preparation step comprising: acquiring a target power of the magnetron; determining a power interval in which the magnetron is located based on the target power, and determining a corresponding control strategy according to the power interval.

3. The filament current and magnetic field current based power output method of claim 2, wherein, The power interval includes a low power segment and a high power segment, and the corresponding filament current control strategy based on the power interval comprises executing a control parameter retrieval instruction according to the power interval to generate a control strategy corresponding to each of the power intervals; The power interval includes a low power segment, a medium power segment, and a high power segment; 4. The filament current and magnetic field current based power output method of claim 3, wherein, The control strategy corresponding to the low power segment comprises: setting the magnetic field current to be 37%~42% of the rated magnetic field current, and executing the corresponding filament current control strategy and power control strategy; The control parameters include a correction factor constant K 3. A filament current index a , a magnetic field strength index b , a magnetron parameter K , an initial magnetic field current reference value, an initial filament current reference value, a PID parameter, and a decoupling compensation coefficient.

5. The filament current and magnetic field current based power output method of claim 4, wherein, The control strategy corresponding to the medium power segment comprises: executing the corresponding filament current control strategy, magnetic field current control strategy, and power control strategy; The control strategy corresponding to the high power segment comprises: setting the value of the filament current to be less than 20% of the rated filament current, and executing the corresponding magnetic field current control strategy and power control strategy. The reference value of the filament current satisfies: The reference value of the magnetic field current satisfies:

6. The filament current and magnetic field current based power output method of claim 1, wherein, ​ ； wherein represents a reference value for the filament current; represents a reference value for the magnetic field current of the previous cycle; is the target power K 3 is a correction factor constant; a is the filament current index; b is the magnetic field strength index; K is the magnetron parameter, which is a constant.

7. The filament current and magnetic field current based power output method of claim 1, wherein, ​ ； wherein represents a reference value for the magnetic field current; represents a reference value for the filament current of the previous cycle; is the target power; K 3 is a correction factor constant; a is the filament current index; b is the magnetic field strength index; K is the magnetron parameter, which is a constant.

8. The filament current and magnetic field current based power output method of claim 5, wherein, When the target power is greater than 0 and less than or equal to 30% of the rated power, the magnetron is in a low-power section; when the target power is greater than 30% and less than or equal to 70% of the rated power, the magnetron is in a medium-power section; and when the target power is greater than 70% and less than or equal to 100% of the rated power, the magnetron is in a high-power section.

9. A power output device based on filament current and magnetic field current, characterized by, The device comprises a magnetron and a microwave power supply for supplying power to the magnetron, and further comprises a processor configured to perform the method of any one of claims 1 to 8.

10. A power output system based on filament current and magnetic field current, characterized by, Comprise: a first processing unit configured to obtain a target power of the magnetron; and configured to determine a power interval in which the magnetron is located based on the target power; and configured to determine that all n cycles are completed when the real-time power of the magnetron is within the set range, otherwise the first processing unit executes the next cycle; a control unit configured to execute a corresponding control strategy based on the power interval, the control strategy comprising a filament current control strategy, a magnetic field current control strategy, and a power control strategy; the control unit comprises: a filament loop PID regulator configured to compare the real-time filament current of the magnetron with a reference value of the filament current, output a first control instruction based on the comparison result to adjust the filament current of the magnetron, and form a closed-loop control of the filament current; a magnetic field loop PID regulator configured to compare the real-time magnetic field current of the magnetron with a reference value of the magnetic field current, output a second control instruction based on the comparison result to adjust the magnetic field current of the magnetron, and form a closed-loop control of the magnetic field current; and a power PID regulator configured to compare the real-time power of the magnetron with the target power after the execution of the filament current control strategy and / or the magnetic field current control strategy is completed, and output a correction amount of the filament current and the magnetic field current based on the comparison result, and input the real-time power of the magnetron, the correction amount of the filament current, and the correction amount of the magnetic field current into the next cycle; a power sensor configured to collect the real-time power of the magnetron after the execution of the control strategy; a starting unit configured to, after all cycles are completed, if the deviation between the real-time power and the target power is greater than a set value and the duration exceeds a set time, restart the first processing unit, the control unit, and the power sensor to execute the corresponding strategy.

11. The filament current and magnetic field current based power output system of claim 10, wherein, The control unit comprises: a filament current controller configured to generate a reference value of the filament current, and collect the real-time filament current of the magnetron; a magnetic field current controller configured to generate a reference value of the magnetic field current, and collect the real-time magnetic field current of the magnetron.

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