Polysilicon power supply half-wave detection method
阅读说明：本技术 多晶硅功率电源半波检测方法 (Polysilicon power supply half-wave detection method ) 是由 张杭 高建虎 张燕 丁洁 于 2019-08-09 设计创作，主要内容包括：本发明提供了一种多晶硅功率电源半波检测方法,将半波检测功能集成在多晶硅功率电源控制器中,以减少硬件投入。利用半波前后还原电压有效值变化的特征,根据控制器当时的工作档位和触发角度,计算出此时系统正常时的输出电压有效值,记为理论值；将此理论值与实际采集到的电压有效值进行比较,当两者偏差大于某一设定值时,并且持续时间大于延时定值认为是半波故障。该方案成本低,检测精度高,实用性强。(The invention provides a polysilicon power supply half-wave detection method, which integrates a half-wave detection function into a polysilicon power supply controller to reduce hardware investment. Calculating the effective value of the output voltage of the system when the system is normal at the moment according to the working gear and the trigger angle of the controller at the moment by utilizing the characteristic of the change of the effective value of the reduction voltage before and after the half wave, and recording the effective value as a theoretical value; comparing the theoretical value with the actually collected effective voltage value, and considering the half-wave fault when the deviation between the theoretical value and the actually collected effective voltage value is greater than a set value and the duration time is greater than the delay fixed value. The scheme has the advantages of low cost, high detection precision and strong practicability.)
1. A polysilicon power supply half-wave detection method is characterized in that: and judging a half-wave by adopting a voltage deviation method, setting a theoretical voltage value as Ut and an actual voltage value as Ur, and judging that the half-wave has a fault when the deviation ratio (Ut-Ur)/Ut of the reduction voltage is greater than a set value and the duration time exceeds a set delay fixed value.
2. The half-wave detection method for the polysilicon power supply according to claim 1, characterized in that: the voltage deviation method is characterized in that a half-wave detection voltage threshold is set, and a half-wave detection function is put into use when the theoretical voltage is larger than the threshold.
3. The half-wave detection method for polysilicon power supply as set forth in claim 1, wherein the voltage deviation ratio is set to 0.04 ~ 1.0.0 and the delay time is set to 0.1s ~ 5 s.
4. The half-wave detection method for the polysilicon power supply according to claim 1, characterized in that: and the reduction voltage theoretical value is a voltage effective value after lamination is calculated according to the gear voltage of the transformer, the current working gear and the trigger angle.
5. The half-wave detection method for the polysilicon power supply according to claim 1, characterized in that: the actual value of the reduction voltage half-wave is an effective value calculated according to a periodic wave point sampled by the controller AD.
6. The half-wave detection method for the polysilicon power supply according to claim 1, characterized in that: the half-wave detection function is integrated in the polysilicon power supply controller, and the original analog quantity and calculated quantity of the power supply controller are used for judging the half-wave.
Technical Field
The invention relates to the field of power supply half-wave detection, and aims at a power supply control system in a polycrystalline silicon production process, in particular to a polycrystalline silicon power supply half-wave detection method.
Background
At present, the mainstream process for producing the polycrystalline silicon is an improved Siemens method, a power supply control system of a polycrystalline silicon reduction furnace is an important part for producing the polycrystalline silicon by the improved Siemens method, and the quality of the control system directly influences the production efficiency of the polycrystalline silicon. Most of reduction heating electric systems of the polycrystalline silicon reduction furnace adopt an alternating current voltage-regulating heating power supply rectified by a thyristor. The heating power supply system is simple in design, the resistance value of the silicon rod is gradually reduced along with the reduction growth of the silicon rod, and the output voltage of the system is adjusted only by changing the conduction angle of a thyristor in the power supply so as to maintain the temperature in the reduction furnace to be constant. The reduction electric system mostly adopts a multi-gear green lamination technology to improve the utilization rate of the transformer, reduce harmonic waves and improve power factors. When the power supply system normally operates, the power supply system outputs alternating-current voltage with symmetrical positive and negative half cycles of two-gear lamination without direct-current component; when a thyristor cannot be conducted in a half cycle due to the damage of a certain component, half-wave voltage is formed, and a direct current component exists in a power supply system at the moment. The direct current components can cause the severe saturation of the transformer iron core, the high distortion of the exciting current, and the generation of a large amount of harmonic waves, which influence the continuous growth of the polycrystalline silicon. The direct current component affects the production of polysilicon, and also has great influence on the transformer, and the severe magnetic saturation increases the loss of the metal structure of the transformer, causes the local overheating phenomenon, damages the insulation, damages the transformer or reduces the service life. The half-wave phenomenon is detected in time, shutdown maintenance is carried out, and the method has important significance for equipment safety and improvement of production quality.
At present, the most common detection method is to add a direct current detection device in a loop, the method needs to increase hardware cost and is influenced by a thyristor resistance-capacitance circuit, and the detection precision of the method is low.
Disclosure of Invention
The invention provides a method for detecting a half-wave of a polysilicon power supply, aiming at solving the problems in the prior art, wherein the half-wave detection function is integrated in a power supply controller, and the voltage half-wave phenomenon is detected by adopting a deviation method of an actual voltage value and a theoretical voltage value.
The method provided by the invention comprises the following steps: and judging the half waves by adopting a voltage deviation method, setting a theoretical voltage value as Ut and an actual voltage value as Ur, and reducing the actually output reduction voltage value Ur when a certain component is damaged and the half waves appear. And when the deviation ratio (Ut-Ur)/Ut of the reduction voltage is larger than a set value, judging that the half-wave fault occurs when the duration time exceeds a set delay fixed value.
Further improved, the voltage deviation method is characterized in that a half-wave detection voltage threshold is set, and a half-wave detection function is put into use when the theoretical voltage is larger than the threshold.
Further improved, the fixed value of the voltage deviation rate is set to be 0.04-1.0, the delay time is set to be 0.1-5 s, half-wave faults can be accurately detected, and misjudgment is avoided.
And further improving, wherein the reduction voltage theoretical value is a voltage effective value after lamination is calculated according to the gear voltage of the transformer, the current working gear and the trigger angle.
Further improved, the actual value of the half-wave of the reduction voltage is an effective value calculated according to a cycle point sampled by the controller AD.
The invention integrates the half-wave detection function into the polysilicon power supply controller, and uses the original analog quantity and calculated quantity of the power supply controller to judge the half-wave without adding hardware equipment. In order to control the triggering of the thyristor, the controller collects the output voltage of the reduction transformer through the mutual inductor and the AD sampling loop. However, the reduction voltage collected by the controller is isolated by the transformer transmission, so that direct current saturation is easy to occur, and the direct current component cannot be accurately collected. In view of the above, it is found through a lot of experiments that when the half wave occurs, the effective value of the analog quantity collected by the controller is reduced to different degrees. The invention provides a voltage half-wave detection criterion by utilizing the characteristic that effective values of reduction voltages before and after half-wave change: according to the current working gear and the trigger angle of the controller, the effective value of the output voltage when the system is normal can be calculated and recorded as a theoretical value; comparing the theoretical value with the actually collected effective voltage value, and considering the half-wave fault when the deviation between the theoretical value and the actually collected effective voltage value is greater than a set value and the duration time is greater than the delay fixed value.
The invention has the beneficial effects that:
1. the voltage half-wave phenomenon is detected by adopting a voltage actual value and theoretical value deviation method, and the scheme has the advantages of low cost, high detection precision and strong practicability.
2. The half-wave detection function is integrated in the polysilicon power supply controller, and the original analog quantity and calculated quantity of the power supply controller are used for judging the half-wave without adding hardware equipment.
Drawings
Fig. 1 is a schematic diagram of a polysilicon power supply control system according to an embodiment of the invention.
Fig. 2 is a flow chart of half-wave detection of voltage according to an embodiment of the present invention.
Detailed Description
The invention will be further explained with reference to the drawings.
As shown in fig. 1, which is a schematic diagram of a polysilicon power supply control system of the present invention, the control principle is as follows:
the gear voltage value of the five-gear transformer is input to the controller, and the sequence is as follows: the
When the V5 single gear works, the output voltage range is 0V-300V; when the V4 and the V5 work in a laminated mode, the output voltage range is 301V-400V; when the V3 and the V4 work in a laminated mode, the output voltage range is 401V-600V; when the V2 and V3 are in laminated work, the output voltage range is 601V-1200V; when the V1 and the V2 are in laminated operation, the output voltage range is 1201V-2650V.
In order to avoid triggering deviation caused by the influence of calculation control errors, an angle is reserved near the zero crossing point and does not work, and a small angle is reserved near the zero crossing point and does not work, so that the influence on the whole voltage value is relatively small and can be ignored. The minimum firing angle for each gear is set as follows: the minimum trigger angle of the V1 gear is 25 degrees, the minimum trigger angle of the V2 gear is 20 degrees, the minimum trigger angle of the V3 gear is 15 degrees, the minimum trigger angle of the V4 gear is 10 degrees, and the minimum trigger angle of the V5 gear is 5 degrees.
The following table shows the theoretical value of the reduction voltage, the actual value of the full-wave voltage and the actual value of the half-wave voltage when the high-grade voltage appears in a half wave under different gears and trigger angles.
The theoretical voltage value calculation formula in the table is as follows:
note: u1 is the high-grade voltage value when two adjacent gears are overlapped, U2 is the low-grade voltage value when two adjacent gears are overlapped, and theta is the high-grade trigger angle.
The smaller the fixed value of the voltage deviation rate is, the more sensitive the detection is, but the deviation between the theoretical value and the actual value when no half-wave occurs is avoided, and the deviation caused by instantaneous interference can be avoided by the delay time. The method is obtained through a large amount of test data, when the voltage deviation rate fixed value is set to be 0.04-0.1, the delay time is set to be 0.1-5 s, half-wave faults can be accurately detected, and misjudgment cannot occur.
Preferably, the voltage deviation ratio set value is set to 0.06, and the delay time is set to 1s, so that the best detection result can be obtained.
As shown in fig. 2, it is a flow chart of half-wave detection of voltage according to the present invention, and the detection flow is as follows:
the controller collects the reduction voltage in real time and calculates an actual effective value Ur of the reduction voltage, meanwhile, a theoretical voltage value Ut is calculated according to the working gear voltage, the current working gear and each gear trigger angle, when the deviation rate | Ut-Ur |/Ut of the reduction voltage is larger than a set value, a half-wave fault is judged through set time delay, the controller stops outputting, a half-wave fault alarm is reported, and operation and maintenance personnel are reminded to search for the fault.
While the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
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