Self-adaptive power adjusting method based on impedance change of electric heating load of kiln

Abstract

The invention provides a self-adaptive power regulation method based on impedance change of an electric heating load of a kiln, which comprises the following steps of: setting a load resistance value, and monitoring peak current output by a power regulator in real time; when the monitored peak current does not exceed the rated peak current of the power regulator, the output power of the power regulator is regulated by controlling the all-on / all-off period of the power regulator in a zero-crossing variable period triggering mode; and when the monitored peak current exceeds the rated peak current of the power regulator, a trigger phase angle alpha is adjusted to switch into a small amount of phase shift in a zero-crossing variable period by combining a phase shift trigger mode, so that the peak current runs below the rated current all the time, and the production temperature of the kiln is controlled. According to the self-adaptive power adjusting method based on the kiln load impedance change, the power of the power adjuster can be adjusted in a self-adaptive mode according to the fact that the impedance change or the aging characteristic of the electric heating load in the kiln heating process is obvious, the heating temperature of the industrial kiln is guaranteed, and therefore the production cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial kilns, and more specifically, to an adaptive power regulation method based on changes in kiln load impedance. Background Art

[0002] Industrial kilns are equipment made of refractory materials for calcining materials or firing products. Industrial kilns are equipped with electric heating loads such as silicon carbon rods, silicon molybdenum rods and molybdenum wires. Materials or fired products are heated and transported in the industrial kiln to complete the firing process.

[0003] In the industrial kiln heating solution, the power regulator SCR acts as the power regulator of the electric heating load and performs PID control throughout the entire time period. However, with the change of the internal temperature of the industrial kiln and the corrosiveness of the sintering material, the resistance of the electric heating load will change accordingly. Although the change range is small, the resistance of the electric heating load will continue to increase with the increase of use time and aging. At present, the resistance of a relatively good electric heating load will increase to about 1.5 times after one year of use. If the electric heating load is frequently replaced in a large industrial kiln, the production cost will be greatly increased. Therefore, how to adapt to adjust the power of the power regulator to ensure the heating temperature of the industrial kiln when the impedance of the electric heating load changes greatly and the aging characteristics are obvious during use is one of the important links in saving production costs. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and deficiencies in the prior art and to provide an adaptive power regulation method based on the change of kiln load impedance. The method can adaptively adjust the power of the power regulator according to the impedance change or obvious aging characteristics of the electric heating load during the kiln heating process to ensure the heating temperature of the industrial kiln, thereby greatly reducing production costs.

[0005] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: an adaptive power regulation method based on the change of kiln load impedance, characterized in that: the load resistance is set, and the peak current output by the power regulator is monitored in real time; when the monitored peak current does not exceed the rated peak current of the power regulator, the zero-crossing variable cycle triggering method is used to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator; when the monitored peak current exceeds the rated peak current of the power regulator, the phase shift triggering method is combined to adjust the trigger phase angle α to cut in a small amount of phase shift during the zero-crossing variable cycle, so that the peak current is always running below the rated current, thereby realizing the control of the kiln production temperature.

[0006] The method of adjusting the trigger phase angle α to introduce a small amount of phase shift during the zero-crossing variable cycle so that the peak current always runs below the rated current means: using the zero-crossing variable cycle triggering method to introduce the phase shift of the trigger phase angle α to adjust the size of the trigger phase angle α, thereby controlling the conduction time of the power regulator to adjust the output power of the power regulator to ensure that the peak current always remains within the rated range.

[0007] The use of zero-crossing variable period triggering mode to control the full-on / full-off period of the power regulator to adjust the output power of the power regulator means: using the zero-crossing variable period triggering mode to control the full-on / full-off period wave number of the power regulator to adjust the output power of the power regulator.

[0008] Before calcining in the kiln, a material database is established to record the phase change characteristics and load change patterns corresponding to the calcination of different materials.

[0009] Set several heating zones for the materials to be processed at different heating stages of the kiln, match the material database, and formulate a segmented heating temperature curve. Set the load resistance and rated peak current of the power regulator for each heating zone. When the kiln is calcining, the load resistance value and the rated peak current of the power regulator can be automatically selected for each heating zone according to the input material information, so as to realize automatic parameter matching.

[0010] Each heating zone monitors the peak current output by the power regulator in real time. Each heating zone automatically switches to a zero-crossing variable cycle trigger mode or a phase-shift trigger mode to adjust the output power of the power regulator based on the peak current output by the power regulator in real time, thereby realizing the control of the production temperature of each heating zone of the kiln.

[0011] A multi-point temperature sensor array is set up in the kiln to monitor the temperature of the kiln environment in real time.

[0012] A temperature sensor is set on the load surface to detect the load temperature in real time.

[0013] Combine the real-time monitoring of the temperature of the kiln environment, the real-time detection of the temperature of the load and the peak current output by the power regulator to make a judgment, and control the switching to use the zero-crossing variable cycle trigger method or the phase-shift trigger method to adjust the output power of the power regulator to achieve the control of the production temperature of each heating zone of the kiln.

[0014] A self-learning mechanism is established to record the parameters and effects of each adjustment of the power regulator output power for optimizing subsequent operations; when an abnormal change in the peak current of the load is monitored, the alarm system is activated to notify the operator in a timely manner.

[0015] The working principle of the method of the present invention is: when the monitored peak current does not exceed the rated peak current of the power regulator, the zero-crossing variable cycle triggering method is used, which can provide stable power output and reduce harmonic interference. However, when the monitored peak current exceeds the rated peak current of the power regulator, when the zero-crossing variable cycle is triggered, the trigger phase angle α is adjusted to cut in a small amount of phase shift, so that the peak current always runs below the rated current. This dynamic adjustment mechanism enables the material calcination process to adapt to various changes in the load, including impedance changes caused by temperature changes and aging caused by long-term use.

[0016] The adaptive power regulation method based on the change of kiln load impedance of the present invention can be applied to loads with small impedance change and small temperature change during electric heating, such as silicon carbon rods, resistance wires, etc. For such loads, the zero-crossing variable cycle triggering method can be used to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator. At the same time, the adaptive power regulation method based on the change of kiln load impedance of the present invention can be applied to loads with large impedance change or temperature change during electric heating, such as silicon molybdenum rods, molybdenum wires, etc. For such loads, the impedance is low in the initial cold state, and the impedance will continue to increase with the increase of temperature. Similarly, when the zero-crossing variable cycle trigger is used, the trigger phase angle α can be adjusted to cut in the phase shift, so that the peak current is always running below the rated current. With the increase of temperature, the phase angle α continues to decrease, and finally when the peak current is the same as the rated current, the zero-crossing variable cycle trigger is fully used. Therefore, the adaptive power regulation method of the present invention has strong versatility and practicality, and can effectively ensure the heating temperature of industrial kilns, thereby greatly reducing production costs.

[0017] In addition, the present invention establishes a material database and a segmented control method to better cope with the dramatic load changes during the material calcination process, effectively handle the thermal coupling effect, and ensure the consistency of the temperature distribution of the entire furnace. Formulating a segmented heating temperature curve and establishing a self-learning mechanism can provide more accurate control parameters according to different materials and calcination states, and provide customized control strategies for different batches of materials, further improving the quality and efficiency of power regulation. The segmented setting of thresholds and rated peak currents of the power regulator and the multi-parameter joint control strategy can identify load change trends in advance and achieve smoother control transitions. When an abnormal change in the peak current of the load is detected, the alarm system is activated, providing the operator with the possibility of timely intervention to deal with any abnormal situation.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects: the adaptive power regulation method based on the change of kiln load impedance of the present invention can adaptively adjust the power of the power regulator according to the impedance change or obvious aging characteristics of the electric heating load during the kiln heating process to ensure the heating temperature of the industrial kiln, thereby greatly reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the present invention using a zero-crossing variable period triggering method to control the output power of the power regulator; Figure 2 It is a schematic diagram of controlling the output power of a power regulator by combining the zero-crossing variable period triggering mode with the phase-shift triggering mode of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0021] Embodiment 1 like Figure 1 and Figure 2 As shown, the adaptive power regulation method based on the change of kiln load impedance of the present invention is as follows: the peak current output by the power regulator is monitored in real time; when the monitored peak current does not exceed the rated peak current of the power regulator, the zero-crossing variable cycle triggering method is used to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator; when the monitored peak current exceeds the rated peak current of the power regulator, the phase shift triggering method is combined to adjust the trigger phase angle α to cut in a small amount of phase shift during the zero-crossing variable cycle, so that the peak current is always running below the rated current, thereby realizing the control of the kiln production temperature.

[0022] Among them, using the zero-crossing variable cycle triggering method to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator means: Figure 1 As shown, the zero-crossing variable period triggering method is used to control the cycle wave number of the power regulator full on / full off to adjust the output power of the power regulator.

[0023] When the zero-crossing cycle is reached, the trigger phase angle α is adjusted to cut in a small amount of phase shift, so that the peak current is always below the rated current. Figure 2 As shown, a phase shift of the trigger phase angle α is introduced by using a zero-crossing variable period triggering mode to adjust the size of the trigger phase angle α, thereby controlling the on-time of the power regulator to adjust the output power of the power regulator to ensure that the peak current is always kept within the rated range.

[0024] The working principle of the method of the present invention is: when the monitored peak current does not exceed the rated peak current of the power regulator, the zero-crossing variable cycle triggering method is used, which can provide stable power output and reduce harmonic interference. However, when the monitored peak current exceeds the rated peak current of the power regulator, when the zero-crossing variable cycle is triggered, the trigger phase angle α is adjusted to cut in a small amount of phase shift, so that the peak current always runs below the rated current. This dynamic adjustment mechanism enables the material calcination process to adapt to various changes in the load, including impedance changes caused by temperature changes and aging caused by long-term use.

[0025] The adaptive power regulation method based on the change of kiln load impedance of the present invention can be applied to loads with small impedance change and small temperature change during electric heating, such as silicon carbon rods, resistance wires, etc. For such loads, the zero-crossing variable cycle triggering method can be used to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator. At the same time, the adaptive power regulation method based on the change of kiln load impedance of the present invention can be applied to loads with large impedance change or temperature change during electric heating, such as silicon molybdenum rods, molybdenum wires, etc. For such loads, the impedance is low in the initial cold state, and the impedance will continue to increase with the increase of temperature. Similarly, when the zero-crossing variable cycle trigger is used, the trigger phase angle α can be adjusted to cut in the phase shift, so that the peak current is always running below the rated current. With the increase of temperature, the phase angle α continues to decrease, and finally when the peak current is the same as the rated current, the zero-crossing variable cycle trigger is completely used. Therefore, the adaptive power regulation method of the present invention has strong versatility and practicality, and can adaptively adjust the power of the power regulator according to the impedance change or obvious aging characteristics of the electric heating load during the kiln heating process to ensure the heating temperature of the industrial kiln, thereby greatly reducing the production cost.

[0026] Embodiment 2 The adaptive power regulation method based on the change of kiln load impedance in this embodiment is as follows: Before the kiln is fired, a material database is established to record the phase change characteristics and load change patterns of different materials. Several heating zones are set for the materials to be processed at different heating stages of the kiln, and the material database is matched to formulate a segmented heating temperature curve. The load resistance and rated peak current of the power regulator are set for each heating zone.

[0027] When the kiln is calcining, the load resistance and rated peak current of the power regulator can be automatically selected for each heating zone according to the input material information to achieve automatic parameter matching. The peak current output by the power regulator is monitored in real time; when the monitored peak current does not exceed the rated peak current of the power regulator, the zero-crossing variable cycle triggering method is used to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator; when the monitored peak current exceeds the rated peak current of the power regulator, the phase shift triggering method is combined to adjust the trigger phase angle α during the zero-crossing variable cycle to cut in a small amount of phase shift, so that the peak current is always running below the rated current, so as to achieve the control of the kiln production temperature.

[0028] A self-learning mechanism is established to record the parameters and effects of each adjustment of the power regulator output power for optimizing subsequent operations; when an abnormal change in the peak current of the load is monitored, the alarm system is activated to notify the operator in a timely manner.

[0029] Among them, using the zero-crossing variable cycle triggering method to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator means: Figure 1As shown, the zero-crossing variable period triggering method is used to control the cycle wave number of the power regulator full on / full off to adjust the output power of the power regulator.

[0030] When the zero-crossing cycle is reached, the trigger phase angle α is adjusted to cut in a small amount of phase shift, so that the peak current is always below the rated current. Figure 2 As shown, a phase shift of the trigger phase angle α is introduced by using a zero-crossing variable period triggering mode to adjust the size of the trigger phase angle α, thereby controlling the on-time of the power regulator to adjust the output power of the power regulator to ensure that the peak current is always kept within the rated range.

[0031] In addition, in this embodiment, a multi-point temperature sensor array can be set in the kiln to monitor the temperature of the kiln environment in real time. A temperature sensor is set on the load surface to detect the load temperature in real time. The real-time monitoring of the temperature of the kiln environment, the real-time detection of the load temperature and the monitoring of the peak current output by the power regulator are combined and judged, and the control switching adopts the zero-crossing variable cycle triggering method or the phase shift triggering method to adjust the output power of the power regulator, so as to realize the control of the production temperature of each heating zone of the kiln.

[0032] The present invention establishes a material database and a segmented control method to better cope with the dramatic load changes during the material calcination process, effectively handle the thermal coupling effect, and ensure the consistency of the temperature distribution of the entire furnace. Formulating a segmented heating temperature curve and establishing a self-learning mechanism can provide more accurate control parameters according to different materials and calcination states, and provide customized control strategies for different batches of materials, further improving the quality and efficiency of power regulation. The segmented setting of thresholds and rated peak currents of the power regulator and the multi-parameter joint control strategy can identify load change trends in advance and achieve smoother control transitions. When an abnormal change in the peak current of the load is detected, the alarm system is activated, providing the operator with the possibility of timely intervention to deal with any abnormal situation.

[0033] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An adaptive power regulation method based on kiln load impedance change, characterized in that: Set the load resistance value and monitor the peak current output by the power regulator in real time; when the monitored peak current does not exceed the rated peak current of the power regulator, the zero-crossing variable cycle trigger method is used to control the full-on / full-off cycle of the power regulator to adjust the output power of the power regulator; when the monitored peak current exceeds the rated peak current of the power regulator, the phase-shift trigger method is combined to adjust the trigger phase angle α during the zero-crossing variable cycle to cut in a small amount of phase shift, so that the peak current is always running below the rated current, thereby realizing the control of the kiln production temperature.

2. The adaptive power regulation method based on kiln load impedance change according to claim 1 is characterized in that: The method of adjusting the trigger phase angle α to introduce a small amount of phase shift during the zero-crossing variable cycle so that the peak current always runs below the rated current means: using the zero-crossing variable cycle triggering method to introduce the phase shift of the trigger phase angle α to adjust the size of the trigger phase angle α, thereby controlling the conduction time of the power regulator to adjust the output power of the power regulator to ensure that the peak current always remains within the rated range.

3. The adaptive power regulation method based on kiln load impedance change according to claim 1 is characterized in that: The use of zero-crossing variable period triggering mode to control the full-on / full-off period of the power regulator to adjust the output power of the power regulator means: using the zero-crossing variable period triggering mode to control the full-on / full-off period wave number of the power regulator to adjust the output power of the power regulator.

4. The adaptive power regulation method based on kiln load impedance change according to claim 1 is characterized in that: Before calcining in the kiln, a material database is established to record the phase change characteristics and load change patterns corresponding to the calcination of different materials.

5. The adaptive power regulation method based on kiln load impedance change according to claim 4 is characterized in that: Set several heating zones for the materials to be processed at different heating stages of the kiln, match the material database, and formulate a segmented heating temperature curve. Set the load resistance and rated peak current of the power regulator for each heating zone. When the kiln is calcining, the load resistance and rated peak current of the power regulator can be automatically selected for each heating zone according to the input material information, so as to realize automatic parameter matching.

6. The adaptive power regulation method based on kiln load impedance change according to claim 5 is characterized in that: Each heating zone monitors the peak current output by the power regulator in real time. Each heating zone automatically switches to a zero-crossing variable cycle trigger mode or a phase-shift trigger mode to adjust the output power of the power regulator based on the peak current output by the power regulator in real time, thereby realizing the control of the production temperature of each heating zone of the kiln.

7. The adaptive power regulation method based on kiln load impedance change according to claim 1 is characterized in that: A multi-point temperature sensor array is set up in the kiln to monitor the temperature of the kiln environment in real time.

8. The method for adaptive power regulation based on kiln load impedance change according to claim 7, characterized in that: A temperature sensor is set on the load surface to detect the load temperature in real time.

9. The adaptive power regulation method based on kiln load impedance change according to claim 8 is characterized in that: Combine the real-time monitoring of the temperature of the kiln environment, the real-time detection of the temperature of the load and the peak current output by the power regulator to make a judgment, and control the switching to use the zero-crossing variable cycle trigger method or the phase-shift trigger method to adjust the output power of the power regulator to achieve the control of the production temperature of each heating zone of the kiln.

10. The adaptive power regulation method based on kiln load impedance change according to claim 1, characterized in that: A self-learning mechanism is established to record the parameters and effects of each adjustment of the power regulator output power for optimizing subsequent operations; when an abnormal change in the peak current of the load is monitored, the alarm system is activated to notify the operator in a timely manner.

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