Temperature-power regulation method based on dual closed-loop active disturbance rejection control

Abstract

A temperature and power regulation method based on dual closed-loop auto-disturbance rejection control comprises the following steps: obtaining real-time temperature data of the surface of a heated workpiece and calculating a temperature error signal between the real-time temperature data and a target temperature value. An outer-loop auto-disturbance rejection control unit is called to estimate the external disturbance of the heated workpiece, obtain an outer-loop disturbance estimate, and compensate the outer-loop disturbance estimate to dynamically adjust the inner-loop power set value. The actual power value output by the inner-loop inverter is obtained, and a power error signal between the actual power value and the inner-loop power set value is calculated. An extended state observer is called to estimate the inner-loop disturbance in real time based on the power error signal, and the switching instructions of the inverter are instantaneously corrected based on the inner-loop disturbance estimate to generate a set of switching control signals. In response to each switching control signal in the set, a corresponding power output is executed, and the heating process of the heated workpiece is frequency tracked through a digital phase-locked loop to obtain a reference frequency after calibration of the digital phase-locked loop.

Description

Technical Field

[0001] The present invention belongs to the technical field of computers and workpiece processing, and more specifically, relates to a temperature-power regulation method based on double closed-loop anti-disturbance control. Background Art

[0002] Currently, traditional workpiece heating methods primarily select the appropriate heating mode based on the workpiece's length. Full-power heating is performed within the temperature sensor's low-temperature blind zone according to set parameters, with no additional control other than necessary overcurrent and overvoltage protection. Furthermore, after the temperature sensor identifies the workpiece's temperature, the PLC controller implements effective temperature tracking control based on the workpiece temperature difference between each coil. In the event of load detuning, frequency conversion is implemented by calculating the power factor at the load end of the power system. When the workpiece temperature approaches a molten state, a temperature PID algorithm is employed. During the insulation phase, the PLC controller sends current modulation output instructions to the DSP controller.

[0003] However, traditional workpiece heating methods rely solely on temperature sensors for temperature measurement, lacking information about temperature deviations. This makes it difficult to adjust to nonlinear changes and interference during subsequent heating compensation. Furthermore, traditional PID controllers are slow to respond to nonlinearities and uncertainties, and the real-time and stability of heating power regulation needs to be further improved. Summary of the Invention

[0004] In order to address the deficiencies in the prior art, the purpose of the present invention is to solve the above-mentioned defects and further propose a temperature-power regulation method based on double closed-loop active disturbance rejection control.

[0005] The present invention adopts the following technical solutions.

[0006] The first aspect of the present invention discloses a temperature-power regulation method based on dual closed-loop active disturbance rejection control, the method comprising:

[0007] Acquiring real-time temperature data of the surface of the heated workpiece, and calculating the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal;

[0008] Invoking an outer-loop active disturbance rejection control unit to estimate the external disturbance of the heated workpiece to obtain an outer-loop disturbance estimate, and compensating the outer-loop disturbance estimate to dynamically adjust the inner-loop power setpoint in combination with the temperature error signal;

[0009] Obtaining an actual power value output by the inner loop inverter, and calculating a difference between the actual power value and the inner loop power set value to obtain a power error signal;

[0010] The power error signal is used as an input of the outer-loop ADRC control unit to invoke an extended state observer to estimate the inner-loop interference in real time, and instantaneously correct the switching command of the inverter according to the inner-loop interference estimate to generate a set of switching control signals;

[0011] Executing a corresponding power output in response to each switch control signal in the switch control signal set, and tracking the frequency of the heating process of the heated workpiece through a digital phase-locked loop when heating the heated workpiece to obtain a reference frequency after calibration of the digital phase-locked loop;

[0012] The external interference includes grid fluctuation and harmonic disturbance, and the inner loop interference includes load resonant frequency drift and instantaneous voltage fluctuation.

[0013] Furthermore, the step of acquiring real-time temperature data of the surface of the heated workpiece and calculating the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal includes:

[0014] By reading the measurement value of the temperature sensor installed on the heated workpiece, real-time temperature data is obtained, and the real-time temperature data is compensated for sensor accuracy and offset correction using a linear model to obtain corrected real-time temperature data;

[0015] Processing the corrected real-time temperature data through digital filtering to obtain the target temperature value, and calculating the difference between the target temperature value and the real-time temperature data before correction to obtain the temperature error signal;

[0016] The linear model uses the sensor range correction coefficient as the slope and the offset correction coefficient as the intercept to correct the real-time temperature data before correction.

[0017] Furthermore, the outer loop ADRC control unit is called to estimate the external interference of the heated workpiece to obtain an outer loop interference estimate, and the outer loop interference estimate is compensated to dynamically adjust the inner loop power set value in combination with the temperature error signal, including:

[0018] calling an outer-loop active disturbance rejection control unit to establish an outer-loop observation environment, and inputting the temperature error signal into the outer-loop observation environment to perform interference estimation on the outer-loop observation environment input through the extended state observer, obtaining the outer-loop interference estimate; the outer-loop active disturbance rejection control unit is constructed using active disturbance rejection control;

[0019] combining the temperature error signal with an outer loop interference estimate to generate a reference value for outer loop power regulation;

[0020] The inner loop power set value is adjusted based on the allowed minimum safe power, the upper limit of the equipment rated power and the reference value.

[0021] Furthermore, the power error signal is used as the input of the outer-loop ADRC control unit to call the extended state observer to estimate the inner-loop interference in real time, and the switching command of the inverter is instantaneously corrected according to the inner-loop interference estimate to generate a set of switching control signals, including:

[0022] An extended state observer of the outer-loop ADRC control unit estimates the interference of the power channel in real time according to the power error signal in accordance with an update rule, thereby obtaining an estimated inner-loop interference estimate;

[0023] Integrating the power error signal with an inner loop interference estimate to generate a power control variable for instantaneously correcting an inverter switching command, and converting the power control variable into a set of switching control signals according to the inverter topology;

[0024] In which, the update rule of the extended state observer is obtained by calculating the power error signal and the random disturbance in the inner loop power path based on a function of comprehensive inference of the power error signal and the unknown interference; the switch control signal set includes at least one first switch control signal and / or at least one second switch signal.

[0025] Furthermore, converting the power control amount into a set of switch control signals according to the topology of the inverter includes:

[0026] When the topology adopts pulse width modulation, the power control variable is mapped to a duty cycle or a switching frequency as a first switch control signal;

[0027] When the topology adopts pulse frequency modulation, the power control variable is mapped to a switching period or a driving timing as the second switch control signal.

[0028] Furthermore, the step of executing corresponding power output in response to each switch control signal in the switch control signal set and performing frequency tracking of the heating process of the heated workpiece through a digital phase-locked loop when heating the heated workpiece to obtain a reference frequency after calibration of the digital phase-locked loop includes:

[0029] receiving the switch control signal set through an inverter, and triggering corresponding power switching devices to output power according to the pulse width modulation and / or pulse frequency modulation, so as to generate corresponding alternating current energy according to each switch control signal, and heating the heated workpiece through the induction coil;

[0030] During the process of the induction coil heating the heated workpiece, the temperature of the workpiece is obtained in real time by a temperature sensor, and the difference between the workpiece temperature and the target temperature value is controlled not to exceed a first threshold value, and the current heating state of the heated workpiece and the current signal flowing through the induction coil are recorded;

[0031] Sampling the current signal flowing through the induction coil through a current transformer or a Hall sensor to obtain a discrete current measurement value, and performing low-pass filtering and calibration on the discrete current measurement value to remove high-frequency noise and measurement deviation in the discrete current measurement value, thereby obtaining a preprocessed load current signal;

[0032] The phase difference between the load current signal and a preset reference signal is calculated by a digital phase-locked loop to correct and update the estimated frequency, obtain an updated frequency estimate, and use the updated frequency estimate as the reference frequency after calibration of the digital phase-locked loop.

[0033] The second aspect of the present invention discloses a temperature-power regulation system based on dual closed-loop active disturbance rejection control, the system comprising:

[0034] a temperature difference calculation module, configured to obtain real-time temperature data of the surface of the heated workpiece, and calculate the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal;

[0035] a dynamic adjustment module, configured to call an outer-loop active disturbance rejection control unit to estimate the external disturbance of the heated workpiece, obtain an outer-loop disturbance estimate, and compensate the outer-loop disturbance estimate to dynamically adjust the inner-loop power setpoint in combination with the temperature error signal;

[0036] a power difference calculation module, configured to obtain an actual power value output by the inner loop inverter, and calculate the difference between the actual power value and the inner loop power set value to obtain a power error signal;

[0037] an instruction correction module, configured to use the power error signal as an input of the outer-loop ADRC control unit to invoke an extended state observer to estimate the inner-loop interference in real time, and to perform instantaneous correction on the switching instructions of the inverter based on the estimated inner-loop interference to generate a set of switching control signals;

[0038] a frequency tracking module, configured to execute a corresponding power output in response to each switch control signal in the switch control signal set, and to perform frequency tracking of a heating process of the heated workpiece through a digital phase-locked loop when heating the heated workpiece, so as to obtain a reference frequency after calibration of the digital phase-locked loop;

[0039] The external interference includes grid fluctuation and harmonic disturbance, and the inner loop interference includes load resonant frequency drift and instantaneous voltage fluctuation.

[0040] A third aspect of the present invention discloses a terminal, comprising a processor and a storage medium, characterized in that:

[0041] The storage medium is used to store instructions;

[0042] The processor is configured to operate according to the instructions to execute the steps of the method of the first aspect.

[0043] A fourth aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, wherein the program implements the steps of the method described in the first aspect when executed by a processor.

[0044] The beneficial effects of the present invention are that, compared with the prior art, the present invention has the following advantages:

[0045] (1) The present invention collects the real-time surface temperature of the heated workpiece through a temperature sensor, and subtracts the measured value from the target temperature to obtain a temperature error signal, which is used to provide more accurate temperature deviation information for subsequent double closed-loop cascade control, ensuring that the subsequent compensation link can make timely adjustments to nonlinear changes and interference.

[0046] (2) The present invention realizes online observation and compensation of random and multiple external interferences through the outer loop self-anti-interference function, improves the adaptability of workpiece processing temperature control, and solves the problem of slow response and easy oscillation of traditional PID to nonlinearity and uncertainty.

[0047] (3) The present invention combines the outer loop anti-interference function with the inner loop to further accurately suppress the influence of factors such as grid fluctuations and resonant frequency drift on power, thereby improving the real-time performance and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a flow chart of a temperature-power regulation method based on double closed-loop active disturbance rejection control. DETAILED DESCRIPTION

[0049] The present application will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present application.

[0050] like Figure 1 As shown, in one embodiment, a temperature-power regulation method based on dual closed-loop active disturbance rejection control includes the following steps:

[0051] Step S110 , acquiring real-time temperature data of the surface of the heated workpiece, and calculating the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal.

[0052] In some embodiments, the temperature-power regulation method based on dual closed-loop active disturbance rejection control provided by the present invention, step S110 specifically includes the following steps:

[0053] In step S111 , real-time temperature data is obtained by reading the measurement value of the temperature sensor installed on the heated workpiece, and a linear model is used to perform sensor accuracy compensation and offset correction on the real-time temperature data to obtain corrected real-time temperature data.

[0054] Step S112 , processing the corrected real-time temperature data through digital filtering to obtain a target temperature value, and calculating the difference between the target temperature value and the real-time temperature data before correction to obtain a temperature error signal.

[0055] Among them, processing the corrected real-time temperature data through digital filtering can effectively reduce the random noise impact of the corrected real-time temperature data. The linear model uses the sensor range correction coefficient as the slope and the offset correction coefficient as the intercept to jointly correct the real-time temperature data before correction.

[0056] Step S120 , calling the outer loop anti-disturbance control unit to estimate the external disturbance of the heated workpiece, obtain the outer loop interference estimation, and compensate the outer loop interference estimation to dynamically adjust the inner loop power set value in combination with the temperature error signal.

[0057] Among them, the outer loop active disturbance rejection control unit includes an extended state observer and nonlinear feedback regulation function. External disturbances include grid fluctuations and harmonic disturbances, and inner loop disturbances include load resonant frequency drift and instantaneous voltage fluctuations.

[0058] In some embodiments, the temperature-power regulation method based on dual closed-loop active disturbance rejection control provided by the present invention, step S120 specifically includes the following steps:

[0059] Step S121: Invoke the outer-loop ADRC control unit to establish an outer-loop observation environment for ADRC. The temperature error signal is input into the outer-loop observation environment. The extended state observer performs interference estimation on the outer-loop observation environment input to obtain an outer-loop interference estimate. The outer-loop ADRC control unit is constructed using ADRC.

[0060] The temperature error signal is input into the outer loop observation environment for temporary storage of the temperature error signal, so that the extended state observer can perform interference estimation on the outer loop observation environment input.

[0061] Step S122: combining the temperature error signal with the outer loop interference estimation to generate a reference value for outer loop power regulation.

[0062] Step S123: adjusting the inner loop power given value based on the allowed minimum safe power, the upper limit of the equipment rated power, and the reference value.

[0063] Step S130 , obtaining the actual power value output by the inner loop inverter, and calculating the difference between the actual power value and the inner loop power set value to obtain a power error signal.

[0064] In step S140 , the power error signal is used as the input of the outer loop ADRC control unit to call the extended state observer to estimate the inner loop interference in real time, and the switching command of the inverter is instantaneously corrected according to the inner loop interference estimate to generate a set of switching control signals.

[0065] In some embodiments, the temperature-power regulation method based on dual closed-loop active disturbance rejection control provided by the present invention, step S140 specifically includes the following steps:

[0066] In step S141 , the extended state observer of the outer-loop ADRC control unit estimates the interference of the power channel in real time according to the power error signal in accordance with an update rule, thereby obtaining an estimated inner-loop interference estimate.

[0067] Step S142 : Integrate the power error signal with the inner loop interference estimation to generate a power control variable for instantaneously correcting the inverter switching command, and convert the power control variable into a set of switching control signals according to the inverter topology.

[0068] In which, the update rule of the extended state observer is obtained by calculating the power error signal and the random disturbance in the inner loop power path based on a function of comprehensive inference of the power error signal and the unknown interference, and the switch control signal set includes at least one first switch control signal and / or at least one second switch signal.

[0069] In some embodiments, the temperature-power regulation method based on dual closed-loop active disturbance rejection control provided by the present invention, step S140 specifically further includes the following steps:

[0070] Step S143: When the topology adopts pulse width modulation, the power control variable is mapped to a duty cycle or a switching frequency as a first switch control signal.

[0071] Step S144: When the topology adopts pulse frequency modulation, the power control variable is mapped to a switching period or a driving timing as a second switch control signal.

[0072] In step S150 , corresponding power output is executed in response to each switch control signal in the switch control signal set, and the heating process of the heated workpiece is frequency tracked through a digital phase-locked loop when heating the heated workpiece to obtain a reference frequency after calibration of the digital phase-locked loop.

[0073] In some embodiments, the temperature-power regulation method based on dual closed-loop active disturbance rejection control provided by the present invention, step S150 specifically includes the following steps:

[0074] In step S151, a switch control signal set is received through an inverter, and corresponding power switch devices are triggered to output power according to pulse width modulation or pulse frequency modulation, so as to generate corresponding AC power according to each switch control signal, and heat the workpiece to be heated through the induction coil.

[0075] Step S152: While the induction coil is heating the workpiece, the temperature of the workpiece is obtained in real time by the temperature sensor, and the difference between the workpiece temperature and the target temperature value is controlled not to exceed a first threshold value. The current heating state of the heated workpiece and the current signal flowing through the induction coil are recorded.

[0076] In step S153, the current signal flowing through the induction coil is sampled by a current transformer or a Hall sensor to obtain a discrete current measurement value, and the discrete current measurement value is low-pass filtered and calibrated to remove high-frequency noise and measurement deviation in the discrete current measurement value to obtain a preprocessed load current signal.

[0077] In step S154 , the phase difference between the load current signal and a preset reference signal is calculated by the digital phase-locked loop to correct and update the estimated frequency, obtain an updated frequency estimate, and use the updated frequency estimate as the reference frequency after calibration of the digital phase-locked loop.

[0078] In a specific embodiment, the temperature-power regulation method based on dual closed-loop active disturbance rejection control provided by the present invention includes steps 1 to 4:

[0079] Step 1: External loop temperature acquisition and error generation.

[0080] The real-time surface temperature of the heated workpiece is collected by the temperature sensor, and the measured value is subtracted from the target temperature to obtain a temperature error signal, which provides accurate temperature deviation information for subsequent double closed-loop cascade control and ensures that the subsequent compensation link can make timely adjustments to nonlinear changes and interference.

[0081] Specifically, it includes steps 1.1 to 1.4:

[0082] Step 1.1, original temperature collection.

[0083] Specifically, the data of the temperature sensor (such as a thermocouple or an infrared temperature measuring device) arranged on the induction heating device is read to obtain the original temperature reading without any correction.

[0084] Step 1.2: Accuracy compensation and offset correction.

[0085] Specifically, the original temperature reading obtained in step 1.1 is subjected to sensor accuracy compensation and offset correction to obtain a corrected temperature.

[0086] Among them, a linear model can be used to compensate the sensor accuracy and offset correction for the original temperature reading, and its expression is:

[0087]

[0088] Where, is the sensor range correction coefficient, which is a constant and can be obtained through calibration within the range of 0.95~1.05; is the offset correction value, which is also a constant and can be selected between -5 and 5°C; is the corrected temperature data, is the original temperature reading before correction, and t is the time.

[0089] Step 1.3: Temperature filtering.

[0090] Specifically, the corrected temperature data obtained in step 1.2 is filtered by digital filtering (such as a first-order low-pass filter) to reduce the influence of random noise and obtain a smoothed temperature value, i.e., the target temperature value. The filtering expression is:

[0091]

[0092] Where, is the filter smoothing coefficient, which can be adjusted within the range of 0.7~0.99. is the discrete sampling period, is the filtered temperature at the previous sampling moment, is the smoothed temperature value after current filtering, is the corrected temperature data, and t is the time.

[0093] Step 1.4, generate a temperature error signal.

[0094] Specifically, the temperature error signal can be obtained by calculating the difference between the current raw temperature reading and the filtered smoothed temperature value.

[0095] Step 2: Dynamically adjust the outer loop ADRC and the inner loop power setpoint.

[0096] The temperature error signal output from step 1 is input to the outer-loop ADRC control unit, which includes an extended state observer (ESO) and a nonlinear feedback control module to estimate and compensate for external disturbances (such as grid fluctuations and harmonic disturbances). The outer-loop ADRC control unit dynamically adjusts the power setpoint by combining the temperature error signal with the outer-loop disturbance estimate. This power setpoint serves as the target input for inner-loop power control, reflecting in real time the need to correct for external disturbances and workpiece temperature rise characteristics. The outer-loop ADRC enables online observation and compensation of random and multiple external disturbances, improving the adaptability of temperature control and addressing the issues of traditional PID control, such as slow response to nonlinearity and uncertainty, and susceptibility to oscillation.

[0097] Specifically, it includes steps 2.1 to 2.4:

[0098] Step 2.1, temperature error signal input and interference observation preparation.

[0099] Specifically, we first establish an outer-loop observation environment for the ADRC system. This environment is ready to receive the temperature error signal calculated in step 1.4 and monitor potential external disturbances (such as grid voltage fluctuations) and internal disturbances (such as changes in workpiece resistivity with temperature). This outer-loop observation environment is used only to store the received temperature error signal, preparing for subsequent processing by the extended state observer.

[0100] In step 2.2, the extended state observer is used to perform interference estimation on the input of the outer loop observation environment.

[0101] Specifically, an extended state observer is used to estimate the outer-loop input disturbance of the induction heating system (controlled object). The resulting estimate is the outer-loop disturbance estimate. This outer-loop disturbance estimate can be converted from a unit temperature error or equivalent thermal disturbance. The extended state observer estimates the disturbance caused by the temperature deviation signal and the external network or load. By online monitoring of the disturbance, the subsequent controller can compensate for its impact in a timely manner.

[0102] 2.3, Interference compensation and power regulation benchmark.

[0103] Specifically, the temperature error signal is combined with the outer loop interference estimate to generate a reference value for power regulation. For example:

[0104]

[0105] Where, is the reference value of the outer ring power output, is the temperature control gain constant, is the interference compensation gain constant, is the temperature error signal, is the outer loop disturbance estimator estimated by the extended state observer, For time.

[0106] Step 2.4: Output the inner loop power setpoint.

[0107] Specifically, the final inner loop power given value is formulated based on the reference value obtained in step 2.3. Saturation limiting or safety constraints can be added here, such as not exceeding the rated power upper limit and not falling below the system minimum operating power threshold.

[0108] Step 3: Inner loop power detection and active disturbance rejection compensation control.

[0109] The inner loop collects the actual output power value of the inverter power supply and compares it with the power set value output in step 2 to obtain a power error signal. The power error signal is then sent to the outer loop self-interference rejection control unit, and the extended state observer inside it is used to estimate interference such as load resonant frequency drift and instantaneous voltage fluctuations in real time. Afterwards, the switching instructions of the inverter are instantly corrected based on the estimation results combined with the power error signal to achieve closed-loop regulation of the output power, so that it quickly approaches the power set value. The present invention further accurately suppresses the influence of factors such as grid fluctuations and resonant frequency drift on power by combining the outer loop self-interference rejection with the inner loop, thereby improving the real-time performance and stability of the system.

[0110] Specifically, it includes steps 3.1 to 3.4:

[0111] Step 3.1: Power detection and power error signal generation.

[0112] Specifically, a power sensor collects the actual inverter output power, typically at the inverter power outlet or in the load circuit. The difference between the actual output power and the set power value is then calculated to generate a power error signal.

[0113] Step 3.2, inner loop expansion state observation estimation.

[0114] Specifically, in the outer-loop active disturbance rejection control architecture, the interference of the power channel is estimated in real time by extending the state observer according to its corresponding update rule to obtain the inner-loop interference estimate.

[0115] The update rule of the extended state observer is obtained by calculating the power error signal and the random disturbance in the inner loop power path based on the function of comprehensive inference of the power error signal and the unknown disturbance, for example:

[0116]

[0117] Where, is the inner loop interference estimator, It represents a function or operation process based on the comprehensive inference of power error signal and unknown interference. is the random or systematic disturbance in the inner loop power path, is the power error signal, and t is the time.

[0118] Step 3.3: Power compensation and control quantity generation.

[0119] Specifically, the power signal error is integrated with the inner-loop interference estimate to generate the power controller's output, the power control variable, which is used to instantaneously correct the inverter switching commands. This power control variable is also determined by the power error gain constant and the interference compensation gain constant. Furthermore, this power control variable is used to directly drive the inverter power switches to quickly correct the deviation between the actual power and the set power value, while also offsetting interference.

[0120] Step 3.4: inverter switch control signal output.

[0121] Specifically, based on the specific inverter topology (e.g., full-bridge, half-bridge, or multi-phase), the power control variables generated in step 3.3 are converted into a set of executable switch control signals. These switch control signals are typically output by a digital signal port or driver board to actually drive power devices such as IGBTs, MOSFETs, or thyristors.

[0122] Among them, if the topology structure uses pulse width modulation, the power control amount is mapped to the duty cycle or switching frequency as the first switch control signal; if the topology structure uses pulse frequency modulation, the power control amount is mapped to the switching period or the corresponding drive timing as the second switch control signal, and at the same time, it is ensured that the hardware safety protection logic, such as current limit or voltage limit, is complied with during the mapping process to avoid overload or device damage.

[0123] Step 4: Frequency tracking and final temperature sampling.

[0124] The load current is synchronously monitored and frequency tracking is performed via a digital phase-locked loop (PLL) to ensure that the inverter operating frequency is consistent or approximately consistent with the load resonant frequency, thereby reducing additional losses and temperature control errors caused by frequency mismatch. The inverter executes the corresponding power output according to the switching control signal generated in step 3, completing the heating of the heated workpiece. The temperature sensor then completes a new round of temperature sampling and processes this temperature value in step 1, forming a dual closed-loop cascade control cycle. This invention alleviates the problem of resonant frequency drift through phase-locked loop frequency tracking and transmits the real-time temperature value back to the outer loop, ensuring the continuous high-precision operation of the dual closed-loop control in dynamic environments.

[0125] Specifically, it includes steps 4.1 to 4.4:

[0126] In step 4.1, the inverter performs a heating process on the workpiece.

[0127] Specifically, the inverter driver board receives the signal and triggers the power switching device according to pulse width modulation or other modulation methods. The inverter then generates corresponding AC energy based on this triggering instruction, and heats the workpiece through the induction coil. At this time, the induction heating system begins to accumulate heat, and the temperature of the heated workpiece gradually rises or remains near the target temperature value. During the workpiece heating process, the above control results are executed, allowing the system to enter the actual heating state, and then the real-time current flowing through the induction coil on the load side during the actual heating process is obtained, and the corresponding current signal is obtained, while the current heating state of the heated workpiece is recorded.

[0128] Step 4.2: Load current sampling and preprocessing.

[0129] Specifically, the current signal obtained in step 4.1 is sampled using a current transformer or Hall sensor to obtain a discrete current measurement value. This discrete current measurement value is then appropriately filtered (e.g., low-pass filtered) and gain calibrated to remove high-frequency noise and measurement deviation, resulting in a smoothed current waveform from which the preprocessed load current signal is derived. At the same time, ensure that the sampling frequency meets the resonant frequency detection requirements. For example, if the resonant frequency is in the range of 1kHz to 100kHz, a sampling rate of 200kHz can be selected.

[0130] Step 4.3, digital phase-locked loop frequency tracking.

[0131] Specifically, the preprocessed load current signal is input into the digital phase-locked loop module to calculate the phase difference between the load current signal and the preset internal reference signal, and then update the estimated frequency. The expression is:

[0132]

[0133] Where, represents the estimated frequency at the nth iteration, represents the estimated frequency at the n+1th iteration; The phase error at the nth iteration (in degrees or radians) is obtained by comparing the load current with a preset internal reference signal. 、 These are the proportional and integral gain constants of the digital phase-locked loop algorithm, which can be selected within the range of 0.001 to 1.0. is the accumulation of phase error, used for integral correction, n is the number of iterations, and k is the number of accumulations of phase error.

[0134] In this embodiment, by continuously correcting the estimated frequency at the nth iteration , and finally, after several sampling cycles, the load current can be aligned with the preset internal reference signal phase, and the approximate resonant frequency after digital phase-locked loop calibration can be obtained.

[0135] Step 4.4, final temperature sampling and reference frequency output.

[0136] Specifically, the This reference frequency is used as the reference frequency after the digital phase-locked loop is calibrated. The temperature sensor is used to obtain the next round of workpiece temperature, which is then transmitted back to the execution process of step 1, forming the next control loop. If the reference frequency after the digital phase-locked loop calibration deviates significantly from the previous reference frequency, a corresponding notification can be sent to the host computer or system for recording, allowing analysis of rapid load changes.

[0137] The following describes the temperature-power regulation system based on dual closed-loop automatic disturbance rejection control provided by the present invention. The temperature-power regulation system based on dual closed-loop automatic disturbance rejection control described below and the temperature-power regulation method based on dual closed-loop automatic disturbance rejection control described above can be referred to each other.

[0138] In one embodiment, a temperature-power regulation system based on dual closed-loop active disturbance rejection control includes a temperature difference calculation module, a dynamic regulation module, a power difference calculation module, a command correction module, and a frequency tracking module.

[0139] The temperature difference calculation module is used to obtain the real-time temperature data of the heated workpiece surface, and calculate the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal.

[0140] The dynamic adjustment module is used to call the outer loop anti-disturbance control unit to estimate the external interference of the heated workpiece, obtain the outer loop interference estimation, and compensate the outer loop interference estimation to dynamically adjust the inner loop power set value in combination with the temperature error signal.

[0141] The power difference calculation module is used to obtain the actual power value output by the inner loop inverter and calculate the difference between the actual power value and the inner loop power set value to obtain a power error signal.

[0142] The command correction module is used to use the power error signal as the input of the outer-loop ADRC control unit to call the extended state observer to estimate the inner-loop interference in real time, and to perform instantaneous correction on the switching command of the inverter based on the inner-loop interference estimate to generate a set of switching control signals.

[0143] The frequency tracking module is used to execute corresponding power output in response to each switch control signal in the switch control signal set, and to perform frequency tracking of the heating process of the heated workpiece through a digital phase-locked loop when heating the heated workpiece to obtain a reference frequency after calibration of the digital phase-locked loop.

[0144] Among them, external interference includes grid fluctuations and harmonic disturbances, and internal loop interference includes load resonant frequency drift and instantaneous voltage fluctuations.

[0145] The present disclosure may be a system, method and / or computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0146] A computer-readable storage medium can be a tangible device that can hold and store instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punched card or raised structure in a groove on which instructions are stored, and any suitable combination thereof. As used herein, a computer-readable storage medium is not to be construed as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse passing through a fiber optic cable), or an electrical signal transmitted through an electrical wire.

[0147] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions to be stored in the computer-readable storage medium in each computing / processing device.

[0148] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, the state information of the computer-readable program instructions is used to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), so that the electronic circuit can execute the computer-readable program instructions, thereby implementing various aspects of the present disclosure.

[0149] Various aspects of the present disclosure are described herein with reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer-readable program instructions.

[0150] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device is generated that implements the functions / actions specified in one or more blocks in the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium, where these instructions cause the computer, programmable data processing device, and / or other device to operate in a specific manner. Thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing various aspects of the functions / actions specified in one or more blocks in the flowchart and / or block diagram.

[0151] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operational steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more blocks in the flowchart and / or block diagram.

[0152] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and the part of the module, program segment or instruction contains one or more executable instructions for realizing the prescribed logical function. In some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the prescribed function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A temperature-power regulation method based on double closed-loop active disturbance rejection control, characterized in that: The method comprises: Acquiring real-time temperature data of the surface of the heated workpiece, and calculating the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal; Invoking an outer-loop active disturbance rejection control unit to estimate the external disturbance of the heated workpiece to obtain an outer-loop disturbance estimate, and compensating the outer-loop disturbance estimate to dynamically adjust the inner-loop power setpoint in combination with the temperature error signal; Obtaining an actual power value output by the inner loop inverter, and calculating a difference between the actual power value and the inner loop power set value to obtain a power error signal; The power error signal is used as an input of the outer-loop ADRC control unit to invoke an extended state observer to estimate the inner-loop interference in real time, and instantaneously correct the switching command of the inverter according to the inner-loop interference estimate to generate a set of switching control signals; Executing a corresponding power output in response to each switch control signal in the switch control signal set, and tracking the frequency of the heating process of the heated workpiece through a digital phase-locked loop when heating the heated workpiece to obtain a reference frequency after calibration of the digital phase-locked loop; The external interference includes grid fluctuations and harmonic disturbances, and the internal loop interference includes load resonant frequency drift and instantaneous voltage fluctuations; The step of acquiring real-time temperature data of the surface of the heated workpiece and calculating the temperature difference between the real-time temperature data and a target temperature value to obtain a temperature error signal includes: Real-time temperature data is obtained by reading the measurement value of a temperature sensor installed on the heated workpiece, and a linear model is used to perform sensor accuracy compensation and offset correction on the real-time temperature data to obtain corrected real-time temperature data; Processing the corrected real-time temperature data through digital filtering to obtain the target temperature value, and calculating the difference between the target temperature value and the real-time temperature data before correction to obtain the temperature error signal; The linear model uses the sensor range correction coefficient as the slope and the offset correction coefficient as the intercept to correct the real-time temperature data before correction. The outer loop auto-disturbance rejection control unit is called to estimate the external disturbance of the heated workpiece to obtain an outer loop disturbance estimate, and the outer loop disturbance estimate is compensated to dynamically adjust the inner loop power set value in combination with the temperature error signal, including: calling an outer-loop active disturbance rejection control unit to establish an outer-loop observation environment, and inputting the temperature error signal into the outer-loop observation environment to perform interference estimation on the outer-loop observation environment input through the extended state observer, obtaining the outer-loop interference estimate; the outer-loop active disturbance rejection control unit is constructed using active disturbance rejection control; combining the temperature error signal with an outer loop interference estimate to generate a reference value for outer loop power regulation; Adjusting the inner loop power set value based on the allowed minimum safe power, the upper limit of the equipment rated power and the reference value; The power error signal is used as the input of the outer-loop ADRC control unit to call the extended state observer to estimate the inner-loop interference in real time, and the switching command of the inverter is instantaneously corrected according to the inner-loop interference estimate to generate a set of switching control signals, including: An extended state observer of the outer-loop ADRC control unit estimates the interference of the power channel in real time according to the power error signal in accordance with an update rule, thereby obtaining an estimated inner-loop interference estimate; Integrating the power error signal with an inner loop interference estimate to generate a power control variable for instantaneously correcting an inverter switching command, and converting the power control variable into a set of switching control signals according to the inverter topology; The update rule of the extended state observer is obtained by calculating the power error signal and the random disturbance in the inner loop power path based on a function of comprehensive inference of the power error signal and the unknown interference; the switch control signal set includes at least one first switch control signal and / or at least one second switch signal; The converting the power control amount into a set of switch control signals according to the topology of the inverter includes: When the topology adopts pulse width modulation, the power control variable is mapped to a duty cycle or a switching frequency as a first switch control signal; When the topology adopts pulse frequency modulation, the power control variable is mapped to a switching period or a driving timing as a second switch control signal; The method includes executing a corresponding power output in response to each switch control signal in the switch control signal set, and tracking the frequency of the heating process of the heated workpiece through a digital phase-locked loop when heating the heated workpiece to obtain a reference frequency after calibration of the digital phase-locked loop, including: receiving the switch control signal set through an inverter, and triggering corresponding power switching devices to output power according to the pulse width modulation and / or pulse frequency modulation, so as to generate corresponding alternating current energy according to each switch control signal, and heating the heated workpiece through the induction coil; During the process of the induction coil heating the heated workpiece, the temperature of the workpiece is obtained in real time by a temperature sensor, and the difference between the workpiece temperature and the target temperature value is controlled not to exceed a first threshold value, and the current heating state of the heated workpiece and the current signal flowing through the induction coil are recorded; Sampling the current signal flowing through the induction coil through a current transformer or a Hall sensor to obtain a discrete current measurement value, and performing low-pass filtering and calibration on the discrete current measurement value to remove high-frequency noise and measurement deviation in the discrete current measurement value, thereby obtaining a preprocessed load current signal; The phase difference between the load current signal and a preset reference signal is calculated by a digital phase-locked loop to correct and update the estimated frequency, obtain an updated frequency estimate, and use the updated frequency estimate as the reference frequency after calibration of the digital phase-locked loop.

2. A temperature-power regulation system based on dual closed-loop active disturbance rejection control, applying the method of claim 1, characterized in that: The system comprises: a temperature difference calculation module, configured to obtain real-time temperature data of the surface of the heated workpiece, and calculate the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal; a dynamic adjustment module, configured to call an outer-loop active disturbance rejection control unit to estimate the external disturbance of the heated workpiece, obtain an outer-loop disturbance estimate, and compensate the outer-loop disturbance estimate to dynamically adjust the inner-loop power setpoint in combination with the temperature error signal; a power difference calculation module, configured to obtain an actual power value output by the inner loop inverter, and calculate the difference between the actual power value and the inner loop power set value to obtain a power error signal; an instruction correction module, configured to use the power error signal as an input of the outer-loop ADRC control unit to invoke an extended state observer to estimate the inner-loop interference in real time, and to perform instantaneous correction on the switching instructions of the inverter based on the estimated inner-loop interference to generate a set of switching control signals; a frequency tracking module, configured to execute a corresponding power output in response to each switch control signal in the switch control signal set, and to perform frequency tracking of a heating process of the heated workpiece through a digital phase-locked loop when heating the heated workpiece, so as to obtain a reference frequency after calibration of the digital phase-locked loop; The external interference includes grid fluctuation and harmonic disturbance, and the inner loop interference includes load resonant frequency drift and instantaneous voltage fluctuation.

3. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to claim 1 .

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to claim 1 are implemented.

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