Temperature power adjusting method based on double-closed-loop active disturbance rejection control

Abstract

A temperature power adjusting method based on double-closed-loop active-disturbance-rejection control comprises the steps that real-time temperature data of the surface of a heated workpiece are obtained, and a temperature error signal between the real-time temperature data and a target temperature value is calculated; and calling an outer ring active-disturbance-rejection control unit to estimate the external disturbance of the heated workpiece to obtain an outer ring disturbance estimator, and compensating the outer ring disturbance estimator to dynamically adjust the inner ring power given value. And acquiring an actual power value output by the inner-loop inverter, and calculating a power error signal between the actual power value and the inner-loop power given value. And calling an extended state observer to estimate inner loop interference in real time according to the power error signal, and performing instantaneous correction on a switching instruction of the inverter according to an inner loop interference estimator to generate a switching control signal set. And executing corresponding power output in response to each switch control signal in the set, and performing frequency tracking on the heating process of the heated workpiece through the digital phase-locked loop so as to obtain the reference frequency calibrated by 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-loop active disturbance rejection control. Background Technique

[0002] Currently, for traditional workpiece heating methods, mainly according to the length of the workpiece, a suitable heating mode is selected, and within the low-temperature blind area of the temperature sensor, full-power heating is performed according to the set parameters, without any control except for necessary over-current and over-voltage protection. In addition, after the temperature sensor identifies the workpiece temperature, the PLC controller performs effective temperature following control according to the temperature difference of the workpiece in each coil; when load dissonance occurs, frequency conversion is implemented by calculating the power factor at the load end of the power supply system; when the workpiece temperature approaches the molten state, a temperature PID algorithm is adopted; during the heat preservation stage, the PLC controller sends an adjustment current modulation output instruction to the DSP controller.

[0003] However, since the traditional workpiece heating method only uses a temperature sensor for temperature measurement and lacks certain temperature deviation information, it is difficult to adjust non-linear changes and disturbances in a timely manner during the subsequent heating compensation process. Moreover, the traditional PID responds slowly to non-linearity and uncertainty, and the real-time performance and stability of its heating power regulation also need to be further improved. Summary of the Invention

[0004] To solve the deficiencies in the prior art, the object of the present invention is to address the above-mentioned defects and further propose a temperature-power regulation method based on double-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 double-loop active disturbance rejection control, and the method includes: Obtain the real-time temperature data on the surface of the workpiece to be heated, and calculate the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal; Call the outer-loop active disturbance rejection control unit to estimate the external disturbance of the workpiece to be heated to obtain an outer-loop disturbance estimation quantity, and compensate the outer-loop disturbance estimation quantity to dynamically adjust the inner-loop power given value in combination with the temperature error signal; 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 given value to obtain a power error signal; Use the power error signal as the input of the outer-loop active disturbance rejection control unit to call the extended state observer to estimate the inner-loop disturbance in real time, and instantaneously correct the switching instruction of the inverter according to the inner-loop disturbance estimation quantity to generate a set of switching control signals; Execute corresponding power output in response to each switch control signal in the set of switch control signals, and perform frequency tracking on the heating process of the workpiece to be heated through a digital phase-locked loop when heating the workpiece to be heated, so as to obtain a reference frequency after calibration by the digital phase-locked loop; Among them, the external interference includes power grid fluctuations and harmonic disturbances, and the internal loop interference includes load resonant frequency drift and instantaneous voltage fluctuations.

[0007] Furthermore, the obtaining of the real-time temperature data on the surface of the workpiece to be heated and the calculation of the temperature difference between the real-time temperature data and the target temperature value to obtain a temperature error signal include: Obtain real-time temperature data by reading the measured values of the temperature sensors installed on the heating workpiece, and perform sensor accuracy compensation and offset correction on the real-time temperature data by using a linear model to obtain corrected real-time temperature data; Process the corrected real-time temperature data through digital filtering to obtain the target temperature value, and calculate the difference between the target temperature value and the real-time temperature data before correction to obtain the temperature error signal; Among them, the linear model corrects the real-time temperature data before correction with the sensor range correction coefficient as the slope and the offset correction coefficient as the intercept.

[0008] Furthermore, the calling of the outer loop active disturbance rejection control unit to estimate the external interference of the workpiece to be heated to obtain an outer loop interference estimation quantity, and compensating the outer loop interference estimation quantity to dynamically adjust the inner loop power given value in combination with the temperature error signal includes: Call the outer loop active disturbance rejection control unit to establish an outer loop observation environment, and input the temperature error signal into the outer loop observation environment, so as to estimate the interference of the input of the outer loop observation environment through the extended state observer to obtain the outer loop interference estimation quantity; the outer loop active disturbance rejection control unit is constructed by using active disturbance rejection control; Combine the temperature error signal and the outer loop interference estimation quantity to generate a reference value for outer loop power adjustment; Adjust the inner loop power given value based on the allowed minimum safety power, the upper limit of the equipment rated power, and the reference value.

[0009] Furthermore, using the power error signal as the input of the outer loop active disturbance rejection control unit to call the extended state observer to estimate the inner loop interference in real time, and instantaneously correct the switching instruction of the inverter according to the inner loop interference estimation quantity to generate a set of switch control signals includes: The extended state observer of the outer loop active disturbance rejection control unit estimates the disturbance of the power channel in real time according to the update rule based on the power error signal, and obtains the estimated inner loop disturbance estimation quantity; Integrate the power error signal and the inner loop disturbance estimation quantity to generate a power control quantity for instantaneously correcting the inverter switching command, and convert the power control quantity into a set of switching control signals according to the topology of the inverter; Wherein, the update rule of the extended state observer is obtained by operating on the power error signal and the random disturbance in the inner loop power path based on a function comprehensively inferred from the power error signal and the unknown disturbance; the set of switching control signals includes at least one first switching control signal and / or at least one second switching signal.

[0010] Further, the converting the power control quantity into a set of switching control signals according to the topology of the inverter includes: When the topology adopts pulse width modulation, map the power control variable to a duty cycle or a switching frequency as the first switching control signal; When the topology adopts pulse frequency modulation, map the power control variable to a switching period or a driving timing as the second switching control signal.

[0011] Further, the performing corresponding power output in response to each switching control signal in the set of switching control signals, and tracking the frequency of the heating process of the workpiece to be heated by a digital phase-locked loop during heating the workpiece to be heated to obtain a reference frequency calibrated by the digital phase-locked loop includes: Receive the set of switching control signals through an inverter, and trigger corresponding power switching devices according to the pulse width modulation and / or pulse frequency modulation to perform power output, so as to generate corresponding alternating current energy according to each switching control signal, and heat the workpiece to be heated through an induction coil; During the process of heating the workpiece to be heated by the induction coil, obtain the workpiece temperature in real time through a temperature sensor, control the difference between the workpiece temperature and the target temperature value not to exceed a first threshold, and record the current heating state of the workpiece to be heated and the current signal flowing through the induction coil; Sample the current signal flowing through the induction coil by a current transformer or a Hall sensor to obtain a discretized current measurement value, and perform low-pass filtering and calibration on the discretized current measurement value to remove high-frequency noise and measurement deviation in the discretized current measurement value, so as to obtain a preprocessed load current signal; Calculate the phase difference between the load current signal and a preset reference signal through a digital phase-locked loop to correct and update the estimated frequency, obtain an updated frequency estimate value, and use the updated frequency estimate value as the reference frequency calibrated by the digital phase-locked loop.

[0012] The second aspect of the present invention discloses a temperature-power regulation system based on double closed-loop active disturbance rejection control. The system includes: A temperature difference calculation module, configured to obtain real-time temperature data on the surface of the workpiece to be heated, and calculate the temperature difference between the real-time temperature data and a target temperature value to obtain a temperature error signal; A dynamic regulation module, configured to call an outer-loop active disturbance rejection control unit to estimate external disturbances of the workpiece to be heated, obtain an outer-loop disturbance estimation quantity, and compensate for the outer-loop disturbance estimation quantity to dynamically regulate an inner-loop power given value in combination with the temperature error signal; A power difference calculation module, configured to obtain an actual power value output by an inner-loop inverter, and calculate the difference between the actual power value and the inner-loop power given value to obtain a power error signal; An instruction correction module, configured to use the power error signal as an input to the outer-loop active disturbance rejection control unit to call an extended state observer to estimate inner-loop disturbances in real time, and instantaneously correct the switching instruction of the inverter according to the inner-loop disturbance estimation quantity to generate a set of switching control signals; A frequency tracking module, configured to execute corresponding power outputs in response to each switching control signal in the set of switching control signals, and perform frequency tracking on the heating process of the workpiece to be heated through a digital phase-locked loop when heating the workpiece to be heated, so as to obtain a reference frequency calibrated by the digital phase-locked loop; Wherein, the external disturbances include power grid fluctuations and harmonic disturbances, and the inner-loop disturbances include load resonant frequency drift and instantaneous voltage fluctuations.

[0013] The third aspect of the present invention discloses a terminal, including 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 described in the first aspect.

[0014] The fourth aspect of the present invention discloses a computer-readable storage medium, on which a computer program is stored, characterized in that when the program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0015] The beneficial effects of the present invention are that, compared with the prior art, the present invention has the following advantages: (1) The present invention collects the real-time surface of the workpiece to be heated through a temperature sensor, subtracts the measured value from the target temperature to obtain a temperature error signal, which provides more accurate temperature deviation information for the subsequent double-loop cascade control and ensures that the subsequent compensation link can be adjusted in a timely manner for non-linear changes and disturbances.

[0016] (2) The present invention realizes the online observation and compensation of random and multiple external disturbances through the outer-loop active disturbance rejection, improves the adaptability of the workpiece processing temperature control, and solves the problems of slow response and easy oscillation of traditional PID to non-linearity and uncertainty.

[0017] (3) By combining the outer-loop active disturbance rejection with the inner loop, the present invention further precisely suppresses the influence of factors such as power grid fluctuations and resonant frequency drift on power, thereby improving the real-time performance and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic flowchart of a temperature-power regulation method based on double-loop active disturbance rejection control. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following further describes the present application with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be used to limit the protection scope of the present application.

[0020] As Figure 1 shown, in one embodiment, a temperature-power regulation method based on double-loop active disturbance rejection control includes the following steps: Step S110: Obtain the real-time temperature data of the surface of the workpiece to be heated, calculate the temperature difference between the real-time temperature data and the target temperature value, and obtain a temperature error signal.

[0021] In some embodiments, the step S110 of the temperature-power regulation method based on double-loop active disturbance rejection control provided by the present invention specifically includes the following steps: Step S111: Obtain the real-time temperature data by reading the measured value of the temperature sensor installed on the heating workpiece, and perform sensor accuracy compensation and offset correction on the real-time temperature data using a linear model to obtain the corrected real-time temperature data.

[0022] Step S112: Process the corrected real-time temperature data through digital filtering to obtain the target temperature value, and calculate the difference between the target temperature value and the real-time temperature data before correction to obtain a temperature error signal.

[0023] Among them, processing the corrected real-time temperature data through digital filtering can effectively reduce the influence of random noise on 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.

[0024] Step S120, call the outer-loop active disturbance rejection control unit to estimate the external disturbance of the workpiece to be heated, obtain the outer-loop disturbance estimation quantity, and compensate the outer-loop disturbance estimation quantity to dynamically adjust the inner-loop power given value in combination with the temperature error signal.

[0025] Among them, the outer-loop active disturbance rejection control unit includes an extended state observer and a nonlinear feedback regulation function. The external disturbances include power grid fluctuations and harmonic disturbances, and the inner-loop disturbances include load resonance frequency drift and instantaneous voltage fluctuations.

[0026] In some embodiments, for the temperature-power regulation method based on double closed-loop active disturbance rejection control provided by the present invention, step S120 specifically includes the following steps: Step S121, call the outer-loop active disturbance rejection control unit to establish an outer-loop observation environment for active disturbance rejection control, and input the temperature error signal into the outer-loop observation environment, so as to estimate the disturbance of the outer-loop observation environment input through the extended state observer to obtain the outer-loop disturbance estimation quantity. The outer-loop active disturbance rejection control unit is constructed by using active disturbance rejection control.

[0027] Among them, inputting the temperature error signal into the outer-loop observation environment is used to temporarily store the temperature error signal, so that the extended state observer can estimate the disturbance of the outer-loop observation environment input.

[0028] Step S122, combine the temperature error signal with the outer-loop disturbance estimation quantity to generate a reference value for outer-loop power regulation.

[0029] Step S123, adjust the inner-loop power given value based on the allowed minimum safety power, the upper limit of the equipment rated power, and the reference value.

[0030] Step S130, 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 given value to obtain a power error signal.

[0031] Step S140, use the power error signal as the input of the outer-loop active disturbance rejection control unit to call the extended state observer to estimate the inner-loop disturbance in real time, and instantaneously correct the switching command of the inverter according to the inner-loop disturbance estimation quantity to generate a set of switching control signals.

[0032] In some embodiments, for the temperature-power regulation method based on double closed-loop active disturbance rejection control provided by the present invention, step S140 specifically includes the following steps: Step S141: The extended state observer of the outer loop active disturbance rejection control unit estimates the disturbance of the power channel in real time according to the power error signal according to the update rule, and obtains the estimated inner loop disturbance estimation quantity.

[0033] Step S142: Integrate the power error signal and the inner loop disturbance estimation quantity to generate a power control quantity for instantaneously correcting the inverter switching instruction, and convert the power control quantity into a set of switching control signals according to the topology of the inverter.

[0034] Among them, the update rule of the extended state observer is obtained by operating on the power error signal and the random disturbance in the inner loop power path by a function inferred comprehensively based on the power error signal and the unknown disturbance. The set of switching control signals includes at least one first switching control signal and / or at least one second switching signal.

[0035] In some embodiments, for the temperature-power regulation method based on double closed-loop active disturbance rejection control provided by the present invention, step S140 specifically further includes the following steps: Step S143: When the topology adopts pulse width modulation, map the power control variable to the duty cycle or the switching frequency as the first switching control signal.

[0036] Step S144: When the topology adopts pulse frequency modulation, map the power control variable to the switching period or the driving timing as the second switching control signal.

[0037] Step S150: Respond to each switching control signal in the set of switching control signals to perform corresponding power output, and perform frequency tracking on the heating process of the workpiece to be heated through a digital phase-locked loop when heating the workpiece to be heated, so as to obtain the reference frequency calibrated by the digital phase-locked loop.

[0038] In some embodiments, for the temperature-power regulation method based on double closed-loop active disturbance rejection control provided by the present invention, step S150 specifically includes the following steps: Step S151: Receive the set of switching control signals through the inverter, and trigger the corresponding power switching device to perform power output according to pulse width modulation or pulse frequency modulation, so as to generate corresponding alternating current energy according to each switching control signal, and heat the workpiece to be heated through the induction coil.

[0039] Step S152: During the process of heating the workpiece to be heated by the induction coil, obtain the workpiece temperature in real time through the temperature sensor and control the difference between the workpiece temperature and the target temperature value not to exceed the first threshold, and record the current heating state of the workpiece to be heated and the current signal flowing through the induction coil.

[0040] Step S153: Sample the current signal flowing through the induction coil via a current transformer or a Hall sensor to obtain a discretized current measurement value, and perform low-pass filtering and calibration on the discretized current measurement value to remove high-frequency noise and measurement deviation in the discretized current measurement value, thereby obtaining a preprocessed load current signal.

[0041] Step S154: Calculate the phase difference between the load current signal and a preset reference signal via a digital phase-locked loop to correct and update the estimated frequency, thereby obtaining an updated frequency estimation value, and use the updated frequency estimation value as the reference frequency calibrated by the digital phase-locked loop.

[0042] In a specific embodiment, the temperature-power regulation method based on double closed-loop active disturbance rejection control provided by the present invention includes Steps 1 to 4: Step 1: Outer-loop temperature acquisition and error generation.

[0043] Collect the real-time surface temperature of the workpiece to be heated via a temperature sensor, and subtract the measurement value from the target temperature to obtain a temperature error signal, providing accurate temperature deviation information for subsequent double closed-loop cascade control and ensuring that the subsequent compensation link can make timely adjustments for non-linear changes and disturbances.

[0044] Specifically, it includes Steps 1.1 to 1.4: Step 1.1: Original temperature acquisition.

[0045] Specifically, read the data of the temperature sensor (such as a thermocouple or an infrared temperature measurement device) arranged on the induction heating device to obtain the original temperature reading without any correction.

[0046] Step 1.2: Precision compensation and offset correction.

[0047] Specifically, perform sensor precision compensation and offset correction on the original temperature reading obtained in Step 1.1 to obtain the corrected temperature.

[0048] Among them, a linear model can be used to perform sensor precision compensation and offset correction on the original temperature reading, and its expression is:

[0049] In the formula, is the sensor range correction coefficient, which is a constant and can be obtained according to calibration within the range of 0.95 to 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 time.

[0050] Step 1.3: Temperature filtering processing.

[0051] Specifically, digital filtering (such as first-order low-pass filtering) is performed on the corrected temperature data obtained in step 1.2 to reduce its random noise influence and obtain a smoothed temperature value, that is, the target temperature value. Its filtering expression is:

[0052] In the formula, is the filtering smoothing coefficient, which can be adjusted within the range of 0.7 to 0.99, is the discrete sampling period, is the filtered temperature at the previous sampling moment, is the current smoothed temperature value after filtering, is the corrected temperature data, and t is time.

[0053] Step 1.4, generate a temperature error signal.

[0054] Specifically, calculate the difference between the current raw temperature reading and the smoothed temperature value after filtering to obtain the temperature error signal.

[0055] Step 2, outer-loop active disturbance rejection control and inner-loop power setpoint dynamic regulation.

[0056] Input the temperature error signal output from step 1 into the outer-loop active disturbance rejection control unit. This outer-loop active disturbance rejection control unit includes an extended state observer (ESO) and a non-linear feedback regulation module, which are used to estimate external disturbances (such as grid voltage fluctuations, harmonic disturbances) and compensate for them. The outer-loop active disturbance rejection control unit dynamically regulates the power setpoint through comprehensive operations on the temperature error signal and the outer-loop disturbance estimation quantity. This power setpoint can be used as the target input for inner-loop power control to reflect in real time the correction requirements for external disturbances and the workpiece heating characteristics. Through outer-loop active disturbance rejection, online observation and compensation of random and multiple external disturbances are achieved, improving the adaptability of temperature control and solving problems such as slow response and easy oscillation of traditional PID to non-linearity and uncertainty.

[0057] Specifically, it includes steps 2.1 to 2.4: Step 2.1, input of the temperature error signal and preparation for disturbance observation.

[0058] Specifically, first establish the outer-loop observation environment of the active disturbance rejection control, prepare to receive the temperature error signal calculated in step 1.4, and monitor possible external disturbances (such as grid voltage fluctuations) and internal disturbances (such as the change of workpiece resistivity with temperature). Among them, the established outer-loop observation environment of the active disturbance rejection control is only used to store the received temperature error signal to prepare for the processing of the subsequent extended state observer.

[0059] Step 2.2: Use an extended state observer to estimate the disturbance of the outer loop observation environment input.

[0060] Specifically, use an extended state observer to estimate the disturbance of the outer loop input of the induction heating system (controlled object). The obtained estimation result is the outer loop disturbance estimation quantity. The unit of this outer loop disturbance estimation quantity is the same as the temperature error or can be converted into an equivalent heat disturbance, which is caused by the temperature deviation signal and the disturbance from the external network or load and is estimated by the extended state observer. Through the online observation of the disturbance, the subsequent controller can compensate for its influence in a timely manner.

[0061] 2.3: Disturbance compensation and power regulation reference.

[0062] Specifically, combine the temperature error signal with the outer loop disturbance estimation quantity to generate a reference value for power regulation. For example:

[0063] In the formula, is the reference value of the outer loop for power output, is the temperature control gain constant, is the disturbance compensation gain constant, is the temperature error signal, is the outer loop disturbance estimation quantity estimated by the extended state observer, is time.

[0064] Step 2.4: Output the inner loop power set value.

[0065] Specifically, based on the reference value obtained in Step 2.3, formulate the final inner loop power set value, and saturation limiting or safety constraints can be added here, such as not exceeding the rated power upper limit and not being lower than the system minimum operating power threshold.

[0066] Step 3: Inner loop power detection and active disturbance rejection compensation control.

[0067] 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. Then, send the power error signal to the outer loop active disturbance rejection control unit, and use the extended state observer inside it to estimate in real time disturbances such as load resonance frequency drift and instantaneous voltage fluctuation. After that, based on the estimation result and combined with the power error signal, make an instantaneous correction to the switching instruction of the inverter to achieve the closed-loop regulation of the output power and make it quickly approach the power set value. Through the combination of the outer loop active disturbance rejection and the inner loop, the present invention further accurately suppresses the influence of factors such as power grid fluctuation and resonance frequency drift on the power, thereby improving the real-time performance and stability of the system.

[0068] Specifically, it includes Steps 3.1 to 3.4: Step 3.1, Power Detection and Power Error Signal Generation.

[0069] Specifically, the actual output power of the inverter is collected through a power sensor, and this process is usually completed at the power outlet of the inverter or in the load circuit. After that, the difference between the actual output power and the given power value is calculated to obtain the power error signal.

[0070] Step 3.2, Inner Loop Extended State Observation Estimation.

[0071] Specifically, in the outer loop active disturbance rejection control architecture, the disturbances in the power channel are estimated in real time by an extended state observer according to its corresponding update rule to obtain the inner loop disturbance estimation quantity.

[0072] Among them, the update rule of the extended state observer is obtained by operating on the power error signal and the random disturbance in the inner loop power path with a function inferred comprehensively based on the power error signal and the unknown disturbance. For example:

[0073] In the formula, is the inner loop disturbance estimation quantity, represents a function or operation process inferred comprehensively based on the power error signal and the unknown disturbance, is the random disturbance or systematic disturbance in the inner loop power path, is the power error signal, and t is time.

[0074] Step 3.3, Power Compensation and Control Quantity Generation.

[0075] Specifically, the power signal error and the inner loop disturbance estimation quantity are integrated to generate the output quantity of the power controller, that is, the power control quantity used to instantaneously correct the inverter switching command. This power control quantity is also jointly determined by the power error gain constant and the disturbance compensation gain constant. In addition, this power control quantity is used to directly drive the inverter power switch to quickly correct the deviation between the actual power and the given power value and offset the disturbance at the same time.

[0076] Step 3.4, Inverter Switching Control Signal Output.

[0077] Specifically, according to the specific topology of the inverter (such as full bridge, half bridge or multi-phase bridge arm), the power control quantity generated in Step 3.3 is converted into an executable set of switching control signals. This switching control signal is usually output from a digital signal port or a driver board and is used to actually drive power devices such as IGBTs, MOSFETs or thyristors.

[0078] Among them, if the topology uses pulse width modulation, the power control quantity is mapped to the duty cycle or the switching frequency as the first switching control signal; if the topology uses pulse frequency modulation, the power control quantity is mapped to the switching period or the corresponding driving timing as the second switching control signal, while ensuring compliance with the hardware safety protection logic such as current limit or voltage limit during the mapping process to avoid overload or device damage.

[0079] Step 4, frequency tracking and final temperature sampling.

[0080] The load current is synchronously monitored and frequency tracking is performed through a digital phase-locked loop (PLL) to ensure that the operating frequency of the inverter is the same as or approximately the same as the load resonance frequency, thereby reducing the additional loss and temperature control error caused by frequency mismatch. The inverter executes the corresponding power output according to the switching control signal generated in step 3, completes the heating of the workpiece to be heated, and then the temperature sensor completes a new round of temperature sampling, and processes the temperature value in step 1 to form a double closed-loop cascade control cycle. The present invention alleviates the resonance frequency drift problem through phase-locked loop frequency tracking and transmits the real-time temperature value back to the outer loop again, ensuring the continuous high-precision operation of the double closed-loop control in a dynamic environment.

[0081] Specifically, it includes steps 4.1 to 4.4: Step 4.1, the inverter executes the heating process of the workpiece.

[0082] Specifically, it is received by the inverter drive board, triggers the power switch device according to pulse width modulation or other modulation methods, and the inverter then generates corresponding AC energy according to the trigger instruction, and heats the workpiece to be heated through the induction coil. At this time, the induction heating system starts to accumulate heat, and the temperature of the workpiece to be heated gradually rises or remains near the target temperature value. During the heating process of the workpiece, the above control results are executed to make the system enter the actual heating state, and then the instantaneous current flowing through the induction coil on the load side during the actual heating process is obtained, and the corresponding current signal is obtained, and the current heating state of the workpiece to be heated is recorded at the same time.

[0083] Step 4.2, load current sampling and preprocessing.

[0084] Specifically, the current signal obtained in step 4.1 is sampled through a current transformer or a Hall sensor to obtain a discretized current measurement value, and then the discretized current measurement value is appropriately filtered (such as low-pass filtering) and gain calibrated to remove the high-frequency noise and measurement deviation therein, and a smoothed current waveform is obtained, and then the preprocessed load current signal is obtained therefrom. At the same time, ensure that the sampling frequency meets the resonance frequency detection requirements. For example, if the resonance frequency is in the range of 1 kHz to 100 kHz, the sampling rate can be selected as 200 kHz.

[0085] Step 4.3, digital phase-locked loop frequency tracking.

[0086] 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 the estimated frequency is updated. The expression is as follows:

[0087] In the formula, represents the estimated frequency at the nth iteration, represents the estimated frequency at the (n + 1)th iteration; represents the phase error (in degrees or radians) at the nth iteration, which is obtained by comparing the load current with the preset internal reference signal; and are the proportional and integral gain constants of the digital phase-locked loop algorithm respectively, and can be selected in the range of 0.001 to 1.0; is the accumulation of the phase error for integral correction. n is the number of iterations, and k is the accumulation times of the phase error.

[0088] In this embodiment, by continuously correcting the estimated frequency at the nth iteration, finally, after several sampling periods, the phase of the load current can be aligned with the preset internal reference signal, and the approximate resonance frequency after digital phase-locked loop calibration can be obtained.

[0089] Step 4.4, final temperature sampling and reference frequency output.

[0090] Specifically, obtained in Step 4.3 is used as the reference frequency after digital phase-locked loop calibration. At the same time, a new round of workpiece temperature is obtained through the temperature sensor, and the new round of workpiece temperature is transmitted back to the execution process of Step 1 to form the next control loop. Among them, if the deviation between the reference frequency after digital phase-locked loop calibration and the previous reference frequency is large, a corresponding notification can be sent to the host computer or system record for analyzing the rapid change condition of the load.

[0091] Next, the temperature-power regulation system based on double closed-loop active disturbance rejection control provided by the present invention will be described. The temperature-power regulation system based on double closed-loop active disturbance rejection control described below can be mutually corresponding and referred to with the temperature-power regulation method based on double closed-loop active disturbance rejection control described above.

[0092] In one embodiment, a temperature-power regulation system based on double closed-loop active disturbance rejection control includes a temperature difference calculation module, a dynamic regulation module, a power difference calculation module, an instruction correction module, and a frequency tracking module.

[0093] The temperature difference calculation module is used to obtain the real-time temperature data of the surface of the workpiece to be heated, calculate the temperature difference between the real-time temperature data and the target temperature value, and obtain a temperature error signal.

[0094] The dynamic adjustment module is used to call the outer-loop active disturbance rejection control unit to estimate the external disturbance of the workpiece to be heated, obtain the outer-loop disturbance estimation quantity, and compensate the outer-loop disturbance estimation quantity to dynamically adjust the inner-loop power given value in combination with the temperature error signal.

[0095] The power difference calculation module is used to obtain the actual power value output by the inner-loop inverter, calculate the difference between the actual power value and the inner-loop power given value, and obtain a power error signal.

[0096] The instruction correction module is used to use the power error signal as the input of the outer-loop active disturbance rejection control unit to call the extended state observer to estimate the inner-loop disturbance in real time, and instantaneously correct the switching instruction of the inverter according to the inner-loop disturbance estimation quantity to generate a set of switching control signals.

[0097] The frequency tracking module is used to execute corresponding power outputs in response to each switching control signal in the set of switching control signals, and perform frequency tracking on the heating process of the workpiece to be heated through a digital phase-locked loop when heating the workpiece to be heated, so as to obtain the reference frequency calibrated by the digital phase-locked loop.

[0098] Among them, the external disturbance includes grid fluctuations and harmonic disturbances, and the inner-loop disturbance includes load resonant frequency drift and instantaneous voltage fluctuations.

[0099] The present disclosure may be a system, a method, and / or a computer program product. The computer program product may include a computer-readable storage medium having thereon computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0100] 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 may 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 of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as a punched card or raised structures in grooves having instructions stored thereon, and any suitable combination of the foregoing. The computer-readable storage medium as used herein is not construed as a transitory signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagated through a waveguide or other transmission medium (e.g., an optical pulse through an optical fiber cable), or an electrical signal transmitted through a wire.

[0101] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to various computing / processing devices, or downloaded to an external computer or external storage device through a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may include a copper transmission cable, an optical fiber transmission, a wireless transmission, a router, a firewall, a switch, a gateway computer, and / or an edge server. A 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 for storage in a computer-readable storage medium in each computing / processing device.

[0102] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine - related 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++, etc., and conventional procedural programming languages such as the "C" language or similar programming languages. The computer - readable program instructions may be executed entirely on the user's computer, partially on the user's computer, executed 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 through 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., through the Internet using an Internet service provider). In some embodiments, by using the state information of the computer - readable program instructions to customize an electronic circuit, such as a programmable logic circuit, a field - programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit can execute the computer - readable program instructions to implement various aspects of the present disclosure.

[0103] Aspects of the present disclosure are described herein with reference to the 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.

[0104] 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 apparatus to produce a machine such that, when the instructions are executed by the processor of the computer or other programmable data - processing apparatus, a device is produced that implements the functions / acts specified in one or more blocks of the flowchart and / or block diagram. These computer - readable program instructions can also be stored in a computer - readable storage medium, which causes a computer, a programmable data - processing apparatus, and / or other devices to operate in a particular manner, so that the computer - readable medium storing the instructions includes a manufacture, which includes instructions for implementing various aspects of the functions / acts specified in one or more blocks of the flowchart and / or block diagram.

[0105] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other devices to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other devices to implement the functions / acts specified in one or more blocks of the flowchart and / or block diagram.

[0106] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a portion of an instruction, which contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two consecutive blocks may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block of the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or acts, or by a combination of dedicated hardware and computer instructions.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A temperature-power regulation method based on double closed-loop anti-disturbance 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 anti-disturbance control unit to estimate the external disturbance of the heated workpiece to obtain an outer loop disturbance estimation, and compensating the outer loop disturbance estimation to dynamically adjust the inner loop power given value in combination with the temperature error signal; Acquire an actual power value output by the inner loop inverter, and calculate a difference between the actual power value and the inner loop power given value to obtain a power error signal; The power error signal is used as an input of the outer loop anti-disturbance 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 estimated amount of the inner loop interference to generate a set of switching control signals; In response to each switch control signal in the switch control signal set, a corresponding power output is executed, and when heating the heated workpiece, a frequency of the heating process of the heated workpiece is tracked through a digital phase-locked loop to obtain a reference frequency after the digital phase-locked loop is calibrated; The external interference includes power grid fluctuation and harmonic disturbance, and the inner loop interference includes load resonant frequency drift and instantaneous voltage fluctuation.

2. The temperature-power regulation method based on double closed-loop anti-disturbance control according to claim 1 is characterized in that: 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: The real-time temperature data is obtained by reading the measured value of the temperature sensor installed on the heated workpiece, and the real-time temperature data is compensated for sensor accuracy and offset correction by using a linear model to obtain corrected real-time temperature data; Processing the corrected real-time temperature data by 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 jointly correct the real-time temperature data before correction.

3. The temperature-power regulation method based on double closed-loop anti-disturbance control according to claim 2 is characterized in that: The calling of the outer loop anti-disturbance control unit to estimate the external disturbance of the heated workpiece to obtain an outer loop disturbance estimation, and compensating the outer loop disturbance estimation to dynamically adjust the inner loop power given value in combination with the temperature error signal, including: Calling an outer loop auto-disturbance rejection control unit to establish an outer loop observation environment, and inputting the temperature error signal into the outer loop observation environment, so as to perform interference estimation on the outer loop observation environment input through the extended state observer, and obtain the outer loop interference estimation; the outer loop auto-disturbance rejection control unit is constructed by adopting auto-disturbance rejection control; Combining the temperature error signal with an outer loop interference estimate to generate a reference value for outer loop power regulation; The inner loop power set value is adjusted based on the allowed minimum safety power, the upper limit of the equipment rated power and the reference value.

4. The temperature-power regulation method based on double closed-loop anti-disturbance control according to claim 3 is characterized in that: The power error signal is used as the input of the outer loop anti-disturbance 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 estimation to generate a set of switching control signals, including: The extended state observer of the outer-loop anti-disturbance control unit estimates the interference of the power channel in real time according to the power error signal in accordance with the update rule, so as to obtain an estimated inner-loop interference estimation; Integrating the power error signal with an inner loop interference estimation amount to generate a power control amount for instantaneously correcting the inverter switching command, and converting the power control amount into a switch control signal set according to the inverter topology; Among them, 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.

5. The temperature-power regulation method based on double closed-loop anti-disturbance control according to claim 4 is characterized in that: The step of 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 the second switch control signal.

6. The temperature-power regulation method based on double closed-loop anti-disturbance control according to claim 5 is characterized in that: The method of executing 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 the digital phase-locked loop is calibrated includes: Receiving the switch control signal set through an inverter, and triggering corresponding power switch 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; In the process of the induction coil heating the heated workpiece, the temperature of the workpiece is obtained in real time through the 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; 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; 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 the digital phase-locked loop is calibrated.

7. A temperature-power regulation system based on double closed-loop anti-disturbance control, characterized in that: The system comprises: A temperature difference calculation module is used 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 is used to call 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 given value in combination with the temperature error signal; A power difference calculation module, used for 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 given value to obtain a power error signal; An instruction correction module is used to use the power error signal as an input of the outer loop anti-disturbance 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 instruction of the inverter according to the inner loop interference estimation to generate a set of switching control signals; A frequency tracking module, configured to execute corresponding power output in response to each switch control signal in the switch control signal set, and to perform frequency tracking on the 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 the digital phase-locked loop is calibrated; The external interference includes power grid fluctuation and harmonic disturbance, and the inner loop interference includes load resonant frequency drift and instantaneous voltage fluctuation.

8. 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 any one of claims 1-6.

9. 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 any one of claims 1 to 6 are implemented.

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