High-frequency induction heating power supply driving method and system

Abstract

The application discloses a high-frequency induction heating power supply driving method and system, the driving method comprising: acquiring an analog electronic signal output by an inverter module in real time; performing A / D conversion on the analog electronic signal to obtain a digital electronic signal; in the sampling stage of A / D conversion, the sampling data comprises first data located at characteristic points of a single-cycle signal and second data located at non-characteristic points of the single-cycle signal, and the number of the second data is much larger than that of the first data; calculating the output power of the inverter module according to the digital electronic signal; comparing the output power with a preset standard power, and generating a first control signal according to the comparison result; and controlling the output of a power adjustment module based on the first control signal, so that the difference between the output power and the standard power is within a preset range. Based on the above method, the response speed of temperature control of a target device can be effectively improved, the precision of temperature control can be greatly improved, and the demand of some special occasions can be met.

Description

Technical Field

[0001] This invention relates to the field of power drive control technology, and in particular to a high-frequency induction heating power drive method and system. Background Technology

[0002] High-frequency induction heating is a method of heating electrical conductors (usually metals) using electromagnetic induction. The principle is as follows: when a current flows through a conductor, a magnetic field is simultaneously generated around it. The high-frequency current flows into an inductor coil (usually made of copper tubing) wound into a loop or other shape, generating a strong magnetic flux with rapidly changing polarity within the coil. When the metal to be heated is placed inside the induction coil, the magnetic flux penetrates the entire material, generating large eddy currents in the opposite direction to the heating current within the material. Due to the resistance of the heated metal, Joule heating occurs, causing the metal's temperature to rise rapidly. High-frequency induction heating equipment based on this principle is widely used, primarily for metal heat treatment, quenching, through-heating, smelting, and welding.

[0003] For current high-frequency induction heating equipment, taking a welding machine as an example, to ensure the welding head reaches the required temperature, temperature control is generally achieved through negative feedback. This involves a temperature sensor collecting the working temperature of the welding head, and then comparing the collected temperature value with a standard value to generate a control signal. However, since the temperature sensor requires a process of at least one second to collect the temperature, and it only collects the surface temperature of the welding head, temperature control via the sensor exhibits a certain lag, meaning a slow response time. Therefore, in applications with high welding requirements and short welding times, such as welding photovoltaic devices, the power driver on the welding machine often only responds after the welding operation is complete, resulting in welding quality that fails to meet user needs.

[0004] Another temperature control method for high-frequency induction heating equipment is to use an open-loop control structure. Taking a welder as an example, upon startup, the drive circuit first detects the voltage and current signals output by the power device and generates a sampled power signal. This sampled power signal is then compared with the target power signal corresponding to a preset temperature point. Based on the comparison result, the output of the power device is adjusted so that the power device outputs the voltage and current signals corresponding to the target temperature point. In generating the sampled power signal, the effective voltage and current are generally calculated using special points such as the extreme points and zero-crossing points of the periodic signal, and then the sampled power value is calculated. However, since these special points cannot completely represent the characteristics of the entire periodic signal, the calculated data differs significantly from the actual values, resulting in a large error in the power signal output by the power device and causing the temperature control accuracy to fail to meet the usage requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a high-frequency induction heating power supply drive system that can effectively improve the response speed and accuracy of temperature control.

[0006] To achieve the above objectives, this invention discloses a high-frequency induction heating power supply driving method. The heating power supply includes a rectifier module, a power adjustment module, an inverter module, and a resonant converter module connected in sequence. The resonant converter module is used to provide an oscillating power driving signal to the induction coil. The driving method includes:

[0007] The analog electronic signals output by the inverter module are acquired in real time, including analog voltage signals and analog current signals;

[0008] The analog electronic signal is converted from digital to digital to obtain a digital electronic signal that includes digital voltage and digital current signals;

[0009] During the sampling stage of the A / D conversion, for any single-cycle signal in the analog electronic signal, a number of sampling data are collected using an equal-interval sampling method. The number of sampling data includes first data located at the feature points of the single-cycle signal and second data located at the non-feature points of the single-cycle signal. The feature points of the single-cycle signal include the start point, end point, zero-crossing point, and extreme point. Moreover, the number of second data is much greater than the number of first data.

[0010] The output power of the inverter module is calculated based on the digital electronic signal;

[0011] The output power is compared with a preset standard power, and a first control signal is generated based on the comparison result;

[0012] The output of the power adjustment module is controlled based on the first control signal so that the difference between the output power and the standard power is within a preset range.

[0013] Preferably, it also includes:

[0014] Calculate the first phase value of the digital voltage signal and the second phase value of the digital current signal, and calculate the phase difference between the first phase value and the second phase value;

[0015] The phase difference is compared with a preset standard deviation, and a second control signal is generated based on the comparison result;

[0016] The frequency of the power signal output by the inverter module is controlled based on the second control signal so that the difference between the phase difference and the standard deviation is within a preset range.

[0017] Preferably, the method further includes: performing fast Fourier transform on the digital voltage signal and the digital current signal respectively to obtain a spectrum reflecting the frequency distribution of voltage and current;

[0018] When the amplitude value of the signal distributed at the high-frequency end in the spectrum exceeds the preset value, a third control signal is generated;

[0019] The power supply to the inverter module is stopped based on the third control signal.

[0020] Preferably, the number N of the sampled data within the single-cycle signal satisfies the following condition: N≥50.

[0021] The present invention also discloses a high-frequency induction heating power supply driving system, which includes a rectifier module, a power adjustment module, an inverter module and a resonant conversion module connected in sequence. The resonant conversion module is used to provide an oscillating power driving signal for the induction coil. The driving system operates based on the high-frequency induction heating power supply driving method described above.

[0022] Preferably, the system further includes a current acquisition unit and a voltage acquisition unit electrically connected to the output terminal of the inverter module. The current acquisition unit is used to acquire the current signal output by the inverter module, and the voltage acquisition unit is used to acquire the voltage signal output by the inverter module. The drive system further includes an A / D converter electrically connected to the current acquisition unit and the voltage acquisition unit, a programmable logic processor electrically connected to the A / D converter, and a controller electrically connected to the programmable logic processor. The controller is also electrically connected to the inverter module and the power adjustment module.

[0023] Preferably, the system further includes a first filter module disposed between the rectifier module and the power adjustment module, and a second filter module disposed between the inverter module and the power adjustment module.

[0024] Preferably, it also includes a neural network-based prediction module, which is electrically connected to the A / D conversion module and the controller. The prediction module is used to predict whether the current output of the inverter module is abnormal based on the digital voltage signal and the digital current signal.

[0025] This invention also discloses a high-frequency induction heating power supply driving system, which includes:

[0026] One or more processors;

[0027] Memory;

[0028] And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the high-frequency induction heating power supply driving method as described above.

[0029] The present invention also discloses a computer-readable storage medium comprising a computer program that can be executed by a processor to perform the high-frequency induction heating power supply driving method as described above.

[0030] Compared with existing technologies, the above-mentioned technical solution of the present invention abandons the traditional closed-loop temperature control method based on temperature sensors and adopts an open-loop temperature control method with high response speed. That is, a standard power corresponding to the target temperature is preset. When the analog electronic signal is collected from the output terminal of the inverter module, the analog electronic signal is converted into a digital electronic signal. During the conversion process, the analog electronic signal is sampled at multiple points throughout each single cycle of the signal. This ensures that the sampled data includes not only the data at the characteristic points of the single cycle signal but also the data at multiple non-characteristic points. As a result, the output power calculated based on the digital electronic signal is infinitely close to the actual output power value of the inverter module. Therefore, based on the above solution, not only can the response speed of the target device temperature control be effectively improved, but the accuracy of temperature control can also be greatly improved, meeting the needs of some special occasions. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the power drive system in an embodiment of the present invention.

[0032] Figure 2 This is a flowchart of a power supply driving method in one embodiment of the present invention.

[0033] Figure 3 This is a flowchart of a power supply driving method in another embodiment of the present invention.

[0034] Figure 4 This is a flowchart of a power supply driving method in another embodiment of the present invention.

[0035] Figure 5 This is a periodic diagram of the analog electronic signal collected in an embodiment of the present invention.

[0036] Figure 6 This is a spectrum diagram of the inverter module under soft switching in an embodiment of the present invention.

[0037] Figure 7 This is a spectrum diagram of the inverter module under hard switching in an embodiment of the present invention. Detailed Implementation

[0038] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0039] This embodiment discloses a high-frequency induction heating power supply driving system for providing driving power to an induction coil based on induction heating. Under the action of this driving power, the temperature of the target part (such as the welding head of a welder) is kept within the target temperature range. Figure 1 The drive system in this embodiment includes a rectifier module, a power adjustment module, an inverter module, and a resonant converter module that are connected in sequence.

[0040] The rectifier module converts AC mains power into DC power input. The power adjustment module adjusts the power of the input power to meet the needs of the induction coil. Based on voltage and / or current signals, the power adjustment module adjusts the output power to the inverter module. In this embodiment, the power adjustment module adjusts the output power by adjusting the voltage, allowing the output voltage to be adjusted to any value within the range of 0 to 540V.

[0041] The resonant conversion module is used to provide an oscillating power drive signal for the induction coil to meet the high-frequency power signal requirements of the induction coil.

[0042] Please refer to the following: Figure 1 and Figure 2 The driving method based on the driving system in this embodiment includes the following steps:

[0043] S1: Real-time acquisition of analog electronic signals output by the inverter module, including analog voltage and analog current signals, such as... Figure 5 .

[0044] S2: Performs A / D conversion on analog electronic signals to obtain digital electronic signals including digital voltage signals and digital current signals.

[0045] During the sampling stage of A / D conversion, for any single-cycle signal in the analog electronic signal, several sampled data points are acquired using an equally spaced sampling method. Please refer to [link / reference needed]. Figure 5The sampled data includes first data located at feature points A, B, C, D, and E of the single-cycle signal, and second data located at a non-feature point P of the single-cycle signal. The feature points of the single-cycle signal include the start point A, the end point E, the zero-crossing point C, and the extreme points B and D. Furthermore, the number of second data points is significantly greater than the number of first data points. In this embodiment, the number of second data points being significantly greater than the number of first data points means that the number of second data points is at least five times the number of first data points. Preferably, the number N of sampled data points within the single-cycle signal best satisfies the following condition: N ≥ 50. In this embodiment, the number of second data points is 95, thus making the total number of sampled data points for the single-cycle signal 100.

[0046] S3: Calculate the output power of the inverter module based on the digital electronic signal.

[0047] S4: Compare the output power with the preset standard power, and generate a first control signal based on the comparison result.

[0048] S5: Control the output of the power adjustment module based on the first control signal so that the difference between the output power and the standard power is within a preset range.

[0049] In this embodiment, a first control signal is generated by monitoring the actual power output of the inverter module. The power adjustment module outputs a corresponding PWM signal to the inverter module based on this first control signal, thereby ensuring that the actual power output of the inverter module corresponds to the target temperature point. During the calculation of the actual power output of the inverter module, each single-cycle signal of the analog electronic signal output by the inverter module is sampled at multiple points throughout the entire cycle. This ensures that the sampled data includes not only data at characteristic points of the single-cycle signal but also data at multiple non-characteristic points, making the output power calculated based on the digital electronic signal infinitely close to the actual power output of the inverter module. Therefore, the driving method executed by the above-described driving system can not only effectively improve the response speed to the temperature control of the target device but also significantly improve the accuracy of temperature control, meeting the needs of some special applications.

[0050] On the other hand, the resonant point of the resonant converter module is not fixed but changes according to the load state. During operation, when the frequency of the power signal output by the inverter module is higher than the resonant point of the resonant converter module, the resonant converter module behaves as an inductor, and the phase of the voltage signal output by the inverter module will lead the phase of the current signal by 90 degrees. Conversely, when the frequency of the power signal output by the inverter module is lower than the resonant point of the resonant converter module, the resonant converter module behaves as a capacitor, and the phase of the voltage signal output by the inverter module will lag the phase of the current signal by 90 degrees. Therefore, when the oscillation frequency of the resonant converter module changes, the phase difference between the voltage and current signals output by the inverter module changes. Thus, by detecting and adjusting the phase difference between the voltage and circuit signals output by the inverter module, the frequency of the voltage and current signals output by the inverter module can be controlled to remain consistent with the resonant point of the resonant converter module in real time, thereby improving the efficiency of the drive power supply. In this regard, as... Figure 3 The driving method in this embodiment further includes:

[0051] S60: Calculate the first phase value of the digital voltage signal and the second phase value of the digital current signal, and calculate the phase difference between the first phase value and the second phase value.

[0052] S61: Compare the phase difference with the preset standard deviation, and generate a second control signal based on the comparison result.

[0053] S62: Control the frequency of the power signal output by the inverter module based on the second control signal so that the difference between the phase difference and the standard deviation is within a preset range.

[0054] On the other hand, if the inverter module continues to operate when abnormal conditions such as short circuits or open circuits occur in the induction coil, it will lead to device damage. For inverter modules that operate based on power transistors, when the induction coil used as the load malfunctions, the power transistors are in a hard-switching state; when the induction coil is operating normally, the power transistors in the inverter module are in a soft-switching state. Therefore, the current operating state of the induction coil can be detected by detecting whether the inverter module is in a soft-switching or hard-switching state.

[0055] By comparing and analyzing the spectral characteristics of the voltage and current signals output by the inverter module in soft-switching and hard-switching states respectively, it can be seen that, for example... Figure 6 (soft switching state) and Figure 7 (Hard switching state) When the inverter module is in hard switching state, its high-frequency energy distribution is significantly higher. However, when the inverter module is in soft switching state, its high-frequency energy distribution is not significant. Therefore, as... Figure 4 The driving method in this embodiment further includes:

[0056] S70: Performs Fast Fourier Transform on the digital voltage signal and digital current signal respectively to obtain a spectrum reflecting the frequency distribution of voltage and current.

[0057] S71: When the amplitude value of the signal distributed at the high-frequency end in the spectrum exceeds the preset value, a third control signal is generated.

[0058] S72: Stop supplying power to the inverter module based on the third control signal.

[0059] In this embodiment, the state changes of the induction coil can be automatically identified based on the third control signal, especially abnormal situations such as short circuits or open circuits in the induction coil, thereby avoiding the risk of the inverter module exploding.

[0060] On the other hand, please refer to again Figure 1 The drive system in this embodiment further includes a current acquisition unit and a voltage acquisition unit electrically connected to the output terminal of the inverter module. The current acquisition unit is used to acquire the current signal output by the inverter module, and the voltage acquisition unit is used to acquire the voltage signal output by the inverter module. The drive system also includes an A / D converter electrically connected to the current and voltage acquisition units, a programmable logic processor (FPGA) electrically connected to the A / D converter, and a controller electrically connected to the FPGA. The controller is also electrically connected to the inverter module and the power adjustment module. In this embodiment, the FPGA is responsible for the spectral transformation and related calculations of the digital electronic signals and transmits the calculation results to the controller. The controller generates corresponding first control signals, second control signals, and third control signals, and accordingly controls the power adjustment module and the inverter module.

[0061] On the other hand, the drive system in this embodiment also includes a first filter module disposed between the rectifier module and the power adjustment module, and a second filter module disposed between the inverter module and the power adjustment module. The first filter module filters the DC signal output by the rectifier module, and the second filter module filters the voltage and current signals output by the power adjustment module again.

[0062] Furthermore, in another preferred embodiment of the high-frequency induction heating power supply drive system of the present invention, a prediction module based on a neural network is also included. The prediction module is electrically connected to the A / D conversion module and the controller. The prediction module is used to predict whether the output of the current inverter module is abnormal based on the digital voltage signal and the digital current signal. When an abnormality is predicted, the module sends a feedback response signal to the controller so that the controller can quickly make a corresponding response.

[0063] In summary, this invention discloses a high-frequency induction heating power supply drive system that drives an induction coil to heat a metal object using induction heating. This drive system employs an open-loop control method based on power signals, enabling rapid heating of the metal object to the target temperature with a fast response speed. Furthermore, by using a high-speed, full-cycle sampling method to process the analog electronic signals acquired from the inverter module, the obtained real-time power signals are more accurate, effectively improving temperature control precision. Additionally, by analyzing the phase of the voltage and current waveforms output by the inverter module, the phase difference between the voltage and current outputs is obtained in real time, ensuring that the frequency of the electrical signal output by the inverter module matches the oscillation frequency of the resonant converter module, effectively improving operating efficiency.

[0064] The present invention also discloses another power drive system, which includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the power drive method as described above. The processor may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, used to execute the relevant program to implement the functions required by the modules in the power drive system of the embodiments of this application, or to execute the power drive method of the method embodiments of this application.

[0065] The present invention also discloses a computer-readable storage medium comprising a computer program executable by a processor to perform the power-driven method described above. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center integrating one or more available media. The available medium can be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as digital versatile discs (DVDs), or semiconductor media, such as solid-state drives (SSDs).

[0066] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the aforementioned power driving method.

[0067] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A high-frequency induction heating power supply drive method characterized by comprising: The heating power supply comprises a rectifier module, a power adjustment module, an inverter module and a resonant conversion module connected in sequence, the resonant conversion module is used for providing an oscillating change power driving signal for an induction coil, and the driving method comprises: an analog electronic signal output by the inverter module is acquired in real time, the analog electronic signal comprises an analog voltage signal and an analog current signal; the analog electronic signal is subjected to A / D conversion to obtain a digital electronic signal comprising a digital voltage signal and a digital current signal; in a sampling stage of the A / D conversion, for a single period signal of any period in the analog electronic signal, a plurality of sampling data are collected by using an equal interval sampling mode, the plurality of sampling data comprise first data located at a characteristic point of the single period signal and second data located at a non-characteristic point of the single period signal, the characteristic point of the single period signal comprises a start point, an end point, a zero-crossing point and an extreme point, and the number of the second data is much larger than the number of the first data; an output power of the inverter module is calculated according to the digital electronic signal; the output power is compared with a preset standard power, and a first control signal is generated according to a comparison result; the output of the power adjustment module is controlled based on the first control signal, so that a difference between the output power and the standard power is within a preset range.

2. The high-frequency induction heating power supply driving method according to claim 1, characterized by, Further comprising: a first phase value of the digital voltage signal and a second phase value of the digital current signal are calculated, and a phase difference between the first phase value and the second phase value is calculated; the phase difference is compared with a preset standard difference, and a second control signal is generated according to a comparison result; a frequency of a power signal output by the inverter module is controlled based on the second control signal, so that a difference between the phase difference and the standard difference is within a preset range.

3. The high-frequency induction heating power supply driving method according to claim 1, characterized by, Further comprising: the digital voltage signal and the digital current signal are subjected to fast Fourier transform respectively to obtain a frequency spectrum reflecting a frequency distribution of voltage and current; when a signal amplitude value distributed at a high frequency end in the frequency spectrum exceeds a preset value, a third control signal is generated; based on the third control signal, power supply to the inverter module is stopped.

4. The high-frequency induction heating power supply driving method according to claim 1, characterized by, The number N of the sampling data in the single period signal satisfies the following condition: N≥50.

5. A high-frequency induction heating power supply drive system, characterized in that, The heating power supply comprises a rectifier module, a power adjustment module, an inverter module and a resonant conversion module connected in sequence, the resonant conversion module is used for providing an oscillating change power driving signal for an induction coil, and the driving system works based on the high-frequency induction heating power supply driving method of any one of claims 1 to 4.

6. The high-frequency induction heating power supply drive system according to claim 5, wherein The drive system further comprises a current collector and a voltage collector electrically connected to the output end of the inverter module, the current collector is used to collect the current signal output by the inverter module, and the voltage collection module is used to collect the voltage signal output by the inverter module; the drive system further comprises an A / D converter electrically connected to the current collector and the voltage collector, a programmable logic processor electrically connected to the A / D converter, and a controller electrically connected to the programmable logic processor, and the controller is further electrically connected to the inverter module and the power adjustment module.

7. The high-frequency induction heating power supply drive system according to claim 5, wherein The drive system further comprises a first filter module arranged between the rectifier module and the power adjustment module and a second filter module arranged between the inverter module and the power adjustment module.

8. The high-frequency induction heating power supply drive system according to claim 6, wherein The drive system further comprises a neural network-based prediction module electrically connected to the A / D conversion module and the controller, the prediction module is used to predict whether the output of the inverter module is abnormal based on the digital voltage signal and the digital current signal.

9. A high-frequency induction heating power supply drive system, characterized in that, comprise: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the programs comprise instructions for executing the high-frequency induction heating power supply driving method as claimed in any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that, comprise a computer program, which can be executed by a processor to complete the high-frequency induction heating power supply driving method as claimed in any one of claims 1 to 4.

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