Automatic high-voltage starting method for six-phase 40-pair rod polycrystalline silicon power regulating system

Abstract

This invention discloses an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power regulation system, belonging to the field of polycrystalline silicon production technology. It includes high-voltage start-up methods for 4-pair silicon cores, 6-pair silicon cores, and 8-pair silicon cores. In this invention, simultaneous start-up of all 6 pairs improves pressure-pressurization efficiency. A stepped pressure-pressurization voltage is set, and after setting the parameters, no operator intervention is required during the pressure-pressurization process, reducing the risk of misoperation. The switching conditions for the 4-pair silicon core breakdown maintenance switch to CJ3 or series connection can be set according to the highest voltage of the reduction transformer, effectively preventing connection failures. The high-voltage start-up uses a single-stage boost, avoiding harmonics during the boost process that could cause thyristor mistriggers and lead to circulating current short circuits. The pressure-pressurization logic eliminates the pressure-pressurization given current; the same given current is used for high-voltage start-up, reduction, and parallel connection, preventing insufficient current at the beginning of the pressure-pressurization stage from affecting furnace temperature rise and thus pressure-pressurization efficiency.

Description

Technical Field

[0001] This invention relates to the field of polycrystalline silicon production technology, specifically to an automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system. Background Technology

[0002] The electrical control process for polysilicon production involves using a high-voltage starting power supply to induce high-voltage breakdown in the silicon core. Once the core has broken down and the current is maintained for a period, the high-voltage breakdown power supply is stopped and switched to a reduction power supply, thus initiating the silicon core reduction growth stage. The high-voltage starting power supply control system is the core component of the high-voltage starting power supply. Currently, the high-voltage starting of 40-pair polysilicon rods consists of three stages: breakdown, maintenance, and freewheeling. Reduction growth is achieved through parallel and series connections. The original furnace bottom electrode cable distribution is as follows: Figure 4 As shown.

[0003] First, the input of the voltage-pressing transformer is drawn from the 2650V range of the reduction transformer and the second range of 1250V (4-pair and 6-pair) and 1500V (8-pair) through the thyristor for voltage regulation. The voltage-pressing transformer can output 0-12KV to perform high-voltage breakdown of the silicon core. The breakdown process of the 4-pair silicon core is as follows: First, the reduction current is set to 50A, and the voltage-pressing current is 32A. Vacuum contactor K21 closes, contactor K11 closes, and contactor CJ1 closes. The voltage-pressing voltage is set to 9000V. During high-voltage startup, the system adjusts the primary voltage of the voltage-pressing transformer through thyristor phase shifting to achieve high-voltage control and breakdown of the silicon core. After the silicon core breaks down, the voltage-pressing transformer has a primary-secondary ratio of 1:3.5. The primary voltage-pressing current is detected by CT7 and rises to the switching condition of 32A. The actual silicon core current is the secondary current of the voltage-pressing transformer, which is 9.14A. When the voltage-pressing voltage is less than 4000V, it can switch to the maintenance heating stage. The voltage-pressing voltage is then adjusted by PT2. The voltage on the primary side of the voltage transformer is calculated using a transformation ratio of 3.5. The silicon core current, i.e., the current in parallel, rises from 0A to 32A, detected by CT7. CJ1 trips, CJ2 closes. When the silicon core current, i.e., the current in parallel, rises to the maintenance current switching condition of 32A or greater, the system enters the restoration freewheeling stage. The restoration freewheeling stage refers to maintaining the silicon core current through the restoration series circuit. CJ2 trips, K11 trips, CJ3 closes. When the silicon core current rises to the set voltage set current of 32A (i.e., the series current is equal to 32A as detected by CT6), freewheeling occurs. The freewheeling stage refers to maintaining the silicon core current at 32A through the series circuit. Similarly, R2 and R3 silicon cores are broken down. When R3 breaks down, the subsequent current, i.e., the current in series, is greater than or equal to the restoration set current of 50A. Then R4 breaks down. When the maintenance current of R4, i.e., the current in parallel, is greater than or equal to 50A, K23, K14, and CJ3 trip, and the circuit breaker QF closing system enters the series mode (e.g., Figure 1 (As shown).

[0004] The breakdown process of 6 pairs of silicon cores: The breakdown mode of the first 4 pairs of silicon cores is the same as that of 4 pairs of rods. When R4 breaks down and enters freewheeling, the system simultaneously breaks down R5 and R6. When the voltage surge current is greater than or equal to 50A and the voltage surge voltage is less than 4000V, R5 and R6 enter CJ2 maintenance. When the parallel current is greater than or equal to the restoration current of 50A, the system enters parallel operation mode (current flow is as follows). Figure 2 ① As shown, at this time, K24, K15, CJ2, and CJ3 are in the closed state. When the operating current reaches the series conversion condition, that is, the series current is greater than 140A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors open, circuit breaker QF closes, and the system enters the series mode (current flow is as shown). Figure 2 (As shown in ②).

[0005] The breakdown process of the 8-pair silicon core: Refer to the breakdown process of the 4-pair silicon core as for R1, R2, R3, and R4; After R5 and R6 are stepped up by the voltage transformer K22, K13, and CJ1, the voltage surge current is greater than or equal to 50A and the voltage surge voltage is less than 4000V. K13 and K22 are tripped, and R5 and R6 await heating; K23 and K14 are tripped to break down R7 and R8. The voltage surge current is greater than or equal to 50A and the voltage surge voltage is less than 4000V. CJ1 is tripped, and CJ2 is tripped to break down R7 and R8. To maintain heating, when the parallel current (i.e., the current holding current of R7 and R8) is greater than or equal to the restoration set current of 50A, K23 and K14 are tripped, and K13 and K22 are closed. The system maintains heating for R5 and R6. When the parallel current is greater than or equal to 50A, K13 is tripped, and K14 is closed. The system simultaneously maintains heating for R5, R6, R7, and R8 (maintaining the silicon core current of R5, R6, R7, and R8, i.e., the parallel current, to reach 50A). When the parallel current is greater than or equal to the restoration set current of 50A, the system enters parallel mode (current flow is as follows). Figure 3 ① As shown, at this time, K22, K14, CJ2, and CJ3 are in the closed state. When the operating current reaches the series conversion condition, that is, the series current is greater than 235A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors open, circuit breaker QF closes, and the system enters the series mode (current flow is as shown). Figure 3 (As shown in ②).

[0006] The main problems with high-voltage startup are as follows: (1) When starting the pressure test, only 4 pairs of rods and 6 pairs of rods can be started at the same time. 8 pairs of rods need to break down 2 pairs of silicon cores at the same time in a single step. The furnace temperature is too low in the early stage to break down the silicon cores. Therefore, the starting condition for 8 pairs of rods is that 4 pairs of rods or 6 pairs of rods R3 breaks down and then switch to freewheeling. The overall pressure test efficiency is low. (2) As the length of the silicon core increases from 3 meters at the beginning of the design to 3.2 meters at the present, there are situations where 4 pairs of rods can be directly switched to series after breaking down and when the first 4 pairs of 6 pairs of rods and 8 pairs of rods are simultaneously freewheeling, they cannot be connected. (3) During the pressure test, as the silicon core gradually breaks down, high voltage is no longer required. The pressure test voltage needs to be manually modified. The uncontrollable factors of humans increase the possibility of misoperation. (4) When CJ1 is switched to CJ2 and CJ2 is switched to CJ3 to maintain freewheeling, the first 3 pairs in the program only recognize the pressure test given current and the HMI touch screen cannot be modified, resulting in low maintenance and freewheeling currents and slow furnace temperature rise, which affects the pressure test efficiency. (5) The harmonics are heavy during the boosting process, and a short circuit occurs in the circulating current of the 1st and 2nd gears during the stacking of the two gears. Summary of the Invention

[0007] This invention aims to solve the aforementioned technical problems by providing an automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system. By adjusting the connection layout of the pressure-pressuring cables at the furnace bottom electrodes, simultaneous start-up of all six phases improves pressure-pressuring efficiency. A stepped pressure-pressuring voltage is set, eliminating the need for operator intervention during the pressure-pressuring process after parameter settings, reducing the risk of misoperation. The switching conditions for the four-pair rod breakdown maintenance switch to CJ3 or series connection can be set according to the highest voltage of the reduction transformer, effectively preventing connection failures. The high-voltage start-up uses a single-stage boost, avoiding harmonics during the boosting process that could cause thyristor mis-triggering and lead to circulating current short circuits. The pressure-pressuring logic eliminates the pressure-pressuring given current; the same given current is used for high-voltage start-up, reduction, and parallel connection, preventing insufficient current at the beginning of the pressure-pressuring phase from affecting furnace temperature rise and thus pressure-pressuring efficiency.

[0008] The objective of this invention is achieved through the following technical solution: An automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system includes a 4-pair rod silicon core high-voltage start-up method, a 6-pair rod silicon core high-voltage start-up method, and an 8-pair rod silicon core high-voltage start-up method. The high-voltage start-up method for the four pairs of silicon core rods includes four pairs of silicon core rod breakdown, four pairs of silicon core rod maintenance, and four pairs of silicon core rod freewheeling. The high-voltage start-up method for the six pairs of silicon core rods includes six pairs of silicon core rod breakdown, six pairs of silicon core rod maintenance, and six pairs of silicon core rod freewheeling. The high-voltage start-up method for the 8 pairs of silicon core rods is as follows: the breakdown process of silicon cores R1, R2, R3, and R4 is the same as that of the 6 pairs of silicon core rods; R5 and R6 are boosted through a voltage-pressurizing transformer. After the silicon core breaks down, the voltage-pressurizing current is greater than or equal to 50A and the voltage-pressurizing voltage is less than 4000V. R5 and R6 await heating; then R7 and R8 are broken down, with a breakdown current greater than or equal to 50A and a breakdown voltage less than 4000V, and R7 and R8 are maintained for heating. When the maintenance current of R7 and R8, i.e., the parallel current, is greater than or equal to the restoration given current of 50A, the polycrystalline silicon power control system maintains heating for R5 and R6. When the parallel current is greater than or equal to 50A, K13 is tripped, and the polycrystalline silicon power control system maintains heating for R5, R6, R7, and R8 simultaneously. When the parallel current is greater than or equal to the restoration given current of 50A, the polycrystalline silicon power control system enters parallel mode. When the operating current reaches the series conversion condition, i.e., the series current is greater than 235A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors trip, and the polycrystalline silicon power control system enters series mode.

[0009] Preferably, it also includes data settings: first, set the restoration given current to 50A, set the first step voltage for voltage suppression: the given voltage when suppressing R1 is 9000V, set the second step voltage for voltage suppression: the given voltage when suppressing R2, R3, and R4 is 7000V, set the third step voltage for voltage suppression: the given voltage when suppressing R5, R6, R7, and R8 is 4000V, and switch the holding voltage to 4000V.

[0010] Preferably, the four pairs of silicon core rods are broken down: the power regulator starts the four pairs of rods to break down. K21 vacuum contactor closes, K11 contactor closes, CJ1 closes. When the high voltage starts, the system adjusts the primary side voltage of the voltage-suppressing transformer through the phase-shift trigger of the thyristor to achieve high voltage control of the silicon core output to break down. After the silicon core breaks down, the voltage-suppressing transformer is activated. The primary-secondary ratio of the voltage-suppressing transformer is 1:3.5. The primary side voltage-suppressing current is detected by CT7 and rises to the conversion condition greater than the set restoration current of 50A.

[0011] Preferably, the four pairs of silicon core rods are maintained as follows: when the voltage is less than 4000V, the circuit can be switched to the maintenance heating stage. During the maintenance heating stage, the silicon core current, i.e. the current parallel current, increases from 0A to 50A. The silicon core current is detected by CT7. CJ1 is opened and CJ2 is closed.

[0012] Preferably, the 4 pairs of silicon core freewheeling circuits are as follows: when the silicon core current, i.e., the parallel current detected by CT7, is greater than or equal to 50A, the system enters the restoration freewheeling stage. The restoration freewheeling stage refers to maintaining the silicon core current through the restoration series circuit. CJ2 is tripped, K11 is tripped, and CJ3 is closed. When the silicon core current, i.e., the series current, is equal to 50A, the system enters the freewheeling stage. The freewheeling stage refers to maintaining the silicon core current at 50A through the series circuit. Similarly, when silicon cores R2 and R3 are broken down, and silicon core R4 breaks down and enters the maintenance stage with a parallel current of 50A, a voltage judgment is added to ensure successful series switching. That is, the sum of the series voltage of R1, R2, and R3 and the parallel voltage of R4 is less than the set 4 pairs of rod series switching voltage of 2300V. At this time, K23, K14, and CJ3 are tripped, circuit breaker QF is closed, and the system enters the series mode.

[0013] Preferably, the six pairs of silicon cores break down as follows: K21 vacuum contactor closes, K11 contactor closes, CJ1 closes. During high-voltage startup, the system adjusts the primary voltage of the voltage-suppressing transformer through a thyristor phase-shift trigger to achieve high-voltage control of the silicon core output and break down. After the silicon core breaks down, the voltage-suppressing transformer is activated. The primary-secondary ratio of the voltage-suppressing transformer is 1:3.5. The primary voltage-suppressing current is detected by CT7 and rises to a level greater than or equal to the set restoration current of 50A.

[0014] Preferably, the 6 pairs of silicon core rods are maintained as follows: when the voltage is less than 4000V, the circuit can be switched to the heating maintenance stage, CJ1 is opened and CJ2 is closed. Preferably, for the 6-pair silicon core freewheeling: when the silicon core current, i.e., the parallel current, is greater than or equal to 50A, it enters the restoration freewheeling stage. The restoration freewheeling stage refers to maintaining the silicon core current through the restoration series circuit, with CJ2 tripping, K11 tripping, and CJ3 closing. When the silicon core current, i.e., the series current at this time, is greater than or equal to 50A, it enters the freewheeling stage. Similarly, for silicon cores R2, R3, and R4, breakdown occurs. When R3 and R4 break down, the maintaining current, i.e., the parallel current, is greater than or equal to the set restoration current of 50A and the series voltage plus the parallel voltage is less than 2300V. When J2 and K22 are tripped, K23 and CJ3 are closed to provide freewheeling current to R1, R2, R3, and R4. When K14 and CJ1 are closed, R5-R6 are broken down. Similarly, when the holding current of R5 and R6, i.e., the parallel current, is greater than or equal to 50A, the system enters parallel mode. At this time, CJ2, CJ3, K23, and K14 are in the closed state. When the series voltage plus the parallel voltage is less than 2300V and the series current is greater than 140A, K23, K14, CJ2, and CJ3 are tripped, circuit breaker QF is closed, and the system enters series operation mode.

[0015] Preferably, the breakdown process of silicon cores R1, R2, R3, and R4 is the same as the breakdown mode of the 6-pair silicon cores; R5 and R6 are stepped up by the voltage-boosting transformer. After the silicon cores break down, the voltage-boosting current is greater than or equal to 50A and the voltage-boosting voltage is less than 4000V when K22, K13, and CJ1 are closed. R5 and R6 wait for heating; K23 and K14 are closed to break down R7 and R8. The voltage-boosting current is greater than or equal to 50A and the voltage-boosting voltage is less than 4000V. CJ1 is opened and CJ2 is closed to maintain heating of R7 and R8. When the maintenance current of R7 and R8, i.e., the parallel current, is greater than or equal to the restoration given current of 50A, K23 and K14 are closed. When circuit breakers K13 and K22 are closed, the system maintains heating for R5 and R6. When the parallel current is greater than or equal to 50A, K13 opens and K14 closes, and the system simultaneously maintains heating for R5, R6, R7, and R8, maintaining the silicon core current of R5, R6, R7, and R8, i.e., the parallel current, to reach 50A. When the parallel current is greater than or equal to the restoration given current of 50A, the system enters parallel mode, at which time K22, K14, CJ2, and CJ3 are in the closed state. When the operating current reaches the series conversion condition, i.e., the series current is greater than 235A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors open and circuit breaker QF closes, and the system enters series mode.

[0016] The beneficial effects of this technical solution are as follows: I. This invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power regulation system. Simultaneous start-up of all six phases improves voltage regulation efficiency. A stepped voltage regulation system is set, eliminating the need for operator intervention during the voltage regulation process after parameter settings, thus reducing the risk of misoperation. The switching conditions for the four-pair breakdown maintenance switch to CJ3 or series connection can be set according to the highest voltage of the reduction transformer, effectively preventing connection failures. The high-voltage start-up uses a single-stage voltage boost, avoiding harmonics during the boost process that could cause thyristor mis-triggering and lead to circulating current short circuits. The voltage regulation logic eliminates the voltage regulation current setting; the same current is used for high-voltage start-up, reduction, and parallel connection, preventing insufficient current at the beginning of the voltage regulation phase from affecting furnace temperature rise and thus impacting voltage regulation efficiency.

[0017] II. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power adjustment system. By adjusting the connection layout of the pressure-pressuring cable on the furnace bottom electrode, the six phases can be started simultaneously, that is, the first two pairs of silicon cores of the 4-pair, 6-pair, and 8-pair systems can be broken down in a single step, thereby improving the overall pressure-pressuring efficiency.

[0018] III. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power regulation system. After 4 pairs of rods break down, the system directly switches to series connection. When the first 4 pairs of rods of the 6th and 8th pairs of rods simultaneously continue current, a situation arises where they cannot be connected. In the original voltage-pressurization program, i.e., the conditions for switching 4 pairs of rods to series connection are: the parallel and series currents are greater than or equal to the set restoration current of 50A, K23, K14, and CJ3 are opened, and QF is closed. The conditions for switching 4 pairs of rods to series connection are modified so that the parallel and series currents are greater than or equal to the set restoration current of 50A and the restoration voltage plus the parallel voltage is less than 2300V. For the 6th and 8th pairs of rods, the voltage judgment for switching from CJ2 to CJ3 after the 3rd and 4th pairs of rods break down is added to the voltage-pressurization program (i.e., when the parallel voltage plus the series voltage is less than 2300V and the parallel and series currents are greater than or equal to the set restoration current of 50A after the 3rd and 4th pairs of rods break down), switching to CJ3 to continue current, ensuring that the broken silicon core can be successfully connected to the restoration current.

[0019] IV. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power regulation system. A stepped voltage is added to the pressure-up process. When the first pair is pressure-up, due to the high silicon core resistance, the first stepped voltage can be set to 9000V (the given voltage for power regulation system startup is automatically set to 9000V). When the second, third, and fourth pairs are pressure-up, because the first pair of silicon cores has broken down and the furnace temperature has increased, the silicon core resistance has decreased, so the second stepped voltage can be set to 7000V (by judging that the first pair of silicon cores has entered the freewheeling stage, i.e., 0V < series voltage < 700V, series current 50A). Similarly, after pressure-up of the 5th, 6th, 7th, and 8th pairs, the third stepped voltage is set to 4000V (1500V < reduction voltage < 2650V, series current 50A). After setting the parameters, no manual voltage modification is required during the pressure-up process, achieving one-button start-up.

[0020] V. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system. In the pressure-up logic, the pressure-up given current 1 is canceled. The same restoration given current is recognized for high-voltage start-up, restoration, and parallel connection. The switching conditions for entering the maintenance state are the pressure-up current value, the maintenance parallel current, the series current during freewheeling, and the series current in the series mode. This avoids the current being too small at the beginning of the pressure-up stage, which affects the furnace temperature rise and thus the pressure-up efficiency.

[0021] VI. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system. The high-voltage start-up adopts a single-stage voltage boost, that is, the power regulation system adjusts the primary side voltage of the voltage-reducing transformer by the phase shift trigger of the thyristor at the 2650V stage of the reduction transformer to achieve breakdown control of the high voltage output of the silicon core, thus avoiding the harmonics in the stacked voltage regulation boost process that cause the thyristor to be falsely triggered and form a circulating current short circuit. Attached Figure Description

[0022] Figure 1 The electrical schematic diagram is for a 4-pair rod power control cabinet. Figure 2 The electrical schematic diagram of the original 6-pair rod power control cabinet; Figure 3 The electrical schematic diagram of the original 8-pair rod power control cabinet; Figure 4 This is a diagram showing the original distribution of electrode cables at the furnace bottom. Figure 5 The electrical schematic diagram of the improved 6-pair rod power control cabinet; Figure 6 The electrical schematic diagram of the improved 8-pair rod power control cabinet; Figure 7 The diagram shows the distribution of the bottom electrode cables after the improvement. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0024] It should be noted that when a component is referred to as being "mounted on," "fixed to," or "set on" another component, it can be directly on the other component or may have an intervening component present. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or may have an intervening component present.

[0025] It should also be noted that the directional terms such as left, right, up, and down in the embodiments of the present invention are only relative concepts or are based on the normal use state of the product, and should not be considered as restrictive.

[0026] The improved distribution of the furnace bottom electrode cables is as follows: Figure 7 As shown, phase B1 has 4 pairs of rods, phases A1 and C1 have 6 pairs of rods, and phases A2, B2, and C2 have 8 pairs of rods. Phase B1 uses the 4-pair silicon core high-voltage start-up method, phases A1 and C1 use the 6-pair silicon core high-voltage start-up method, and phases A2, B2, and C2 use the 8-pair silicon core high-voltage start-up method.

[0027] An automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system includes the following steps: including a 4-pair rod silicon core high-voltage start-up method, a 6-pair rod silicon core high-voltage start-up method, and an 8-pair rod silicon core high-voltage start-up method. The high-voltage start-up method for the four pairs of silicon core rods includes four pairs of silicon core rod breakdown, four pairs of silicon core rod maintenance, and four pairs of silicon core rod freewheeling. The high-voltage start-up method for the six pairs of silicon core rods includes six pairs of silicon core rod breakdown, six pairs of silicon core rod maintenance, and six pairs of silicon core rod freewheeling. The high-voltage start-up method for the 8 pairs of silicon core rods is as follows: the breakdown process of silicon cores R1, R2, R3, and R4 is the same as that of the 6 pairs of silicon core rods; R5 and R6 are boosted through a voltage-pressurizing transformer. After the silicon core breaks down, the voltage-pressurizing current is greater than or equal to 50A and the voltage-pressurizing voltage is less than 4000V. R5 and R6 await heating; then R7 and R8 are broken down, with a breakdown current greater than or equal to 50A and a breakdown voltage less than 4000V, and R7 and R8 are maintained for heating. When the maintenance current of R7 and R8, i.e., the parallel current, is greater than or equal to the restoration given current of 50A, the polycrystalline silicon power control system maintains heating for R5 and R6. When the parallel current is greater than or equal to 50A, K13 is tripped, and the polycrystalline silicon power control system maintains heating for R5, R6, R7, and R8 simultaneously. When the parallel current is greater than or equal to the restoration given current of 50A, the polycrystalline silicon power control system enters parallel mode. When the operating current reaches the series conversion condition, i.e., the series current is greater than 235A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors trip, and the polycrystalline silicon power control system enters series mode.

[0028] This includes data settings: first, set the restoration current to 50A; set the first step voltage for applying pressure to R1 to 9000V; set the second step voltage for applying pressure to R2, R3, and R4 to 7000V; set the third step voltage for applying pressure to R5, R6, R7, and R8 to 4000V; and set the switching sustaining voltage to 4000V.

[0029] The breakdown of the four pairs of silicon core rods is as follows: the power regulator starts the four pairs of rods to break down. K21 vacuum contactor closes, K11 contactor closes, CJ1 closes. When the high voltage starts, the system adjusts the primary voltage of the voltage-suppressing transformer through the phase shift trigger of the thyristor to achieve high voltage control of the silicon core output to break down. After the silicon core breaks down, the voltage-suppressing transformer is activated. The primary-secondary ratio of the voltage-suppressing transformer is 1:3.5. The primary voltage-suppressing current is detected by CT7 and rises to the conversion condition greater than the set restoration current of 50A.

[0030] Among them, the four pairs of silicon core rods are maintained as follows: when the voltage is less than 4000V, the system can switch to the maintenance heating stage. The voltage is obtained by detecting the primary side voltage of the voltage transformer through PT2 and then calculating it using a turns ratio of 3.5. During the maintenance heating stage, the silicon core current, i.e. the current in parallel, increases from 0A to 50A. The silicon core current is obtained by detecting CT7. CJ1 is opened and CJ2 is closed.

[0031] The four pairs of silicon core freewheeling circuits are as follows: When the silicon core current, i.e., the parallel current detected by CT7, is greater than or equal to 50A, the system enters the restoration freewheeling stage. The restoration freewheeling stage refers to maintaining the silicon core current through the restoration series circuit. CJ2 trips, K11 trips, and CJ3 closes. When the silicon core current, i.e., the series current, is equal to 50A, the system enters the freewheeling stage. The freewheeling stage refers to maintaining the silicon core current at 50A through the series circuit. Similarly, when silicon cores R2 and R3 are broken down, and when silicon core R4 breaks down and enters the maintenance stage with a parallel current of 50A, a voltage judgment is added to ensure successful series switching. That is, the sum of the series voltage of R1, R2, and R3 and the parallel voltage of R4 is less than the set series switching voltage of the four pairs of rods, 2300V. At this time, K23, K14, and CJ3 trip, circuit breaker QF closes, and the system enters the series mode.

[0032] Preferably, the six pairs of silicon cores break down as follows: K21 vacuum contactor closes, K11 contactor closes, CJ1 closes. During high-voltage startup, the system adjusts the primary voltage of the voltage-suppressing transformer through a thyristor phase-shift trigger to achieve high-voltage control of the silicon core output and break down. After the silicon core breaks down, the voltage-suppressing transformer is activated. The primary-secondary ratio of the voltage-suppressing transformer is 1:3.5. The primary voltage-suppressing current is detected by CT7 and rises to a level greater than or equal to the set restoration current of 50A.

[0033] Among them, the 6 pairs of silicon core rods are maintained as follows: when the voltage is less than 4000V, the circuit can be switched to the maintenance heating stage, CJ1 is opened and CJ2 is closed.

[0034] Among them, the 6 pairs of silicon core freewheeling circuits are as follows: when the silicon core current, i.e., the parallel current, is greater than or equal to 50A, the circuit enters the restoration freewheeling stage. The restoration freewheeling stage refers to maintaining the silicon core current through the restoration series circuit, with CJ2 tripping, K11 tripping, and CJ3 closing. When the silicon core current, i.e., the series current at this time, is greater than or equal to 50A, the circuit enters the freewheeling stage. Similarly, silicon cores R2, R3, and R4 are broken down. When R3 and R4 break down, the maintaining current, i.e., the parallel current, is greater than or equal to the set restoration current of 50A and the series voltage plus the parallel voltage is less than 2300V. When J2 and K22 are tripped, K23 and CJ3 are closed to provide freewheeling current to R1, R2, R3, and R4. When K14 and CJ1 are closed, R5-R6 are broken down. Similarly, when the holding current of R5 and R6 (i.e., the parallel current) is greater than or equal to 50A, the system enters parallel mode. At this time, CJ2, CJ3, K23, and K14 are closed. When the operating series voltage plus the parallel voltage is less than 2300V and the series current is greater than 140A, K23, K14, CJ2, and CJ3 are tripped, circuit breaker QF is closed, and the system enters series operation mode (e.g., Figure 5 (As shown).

[0035] Preferably, in the case of 8-pair silicon core breakdown: the breakdown process of silicon cores R1, R2, R3, and R4 is the same as that of 6-pair silicon core breakdown; R5 and R6 are stepped up through the voltage-boosting transformer. After K22, K13, and CJ1 close, the voltage-boosting current is greater than or equal to 50A and the voltage-boosting voltage is less than 4000V. K13 and K22 are then opened, and R5 and R6 wait for heating; K23 and K14 close to break down R7 and R8. The voltage-boosting current is greater than or equal to 50A and the voltage-boosting voltage is less than 4000V. CJ1 is then opened, and CJ2 closes to maintain heating of R7 and R8. When the maintenance current of R7 and R8, i.e., the parallel current, is greater than or equal to the restoration given current of 50A, K23 and K14 close. When circuit breaker 14 trips, circuit breakers K13 and K22 close, and the system maintains heating for resistors R5 and R6. When the parallel current is greater than or equal to 50A, circuit breaker K13 trips, and circuit breaker K14 closes. The system simultaneously maintains heating for resistors R5, R6, R7, and R8, maintaining the silicon core current of R5, R6, R7, and R8, i.e., the parallel current, at 50A. When the parallel current is greater than or equal to the restored set current of 50A, the system enters parallel mode, at which point circuit breakers K22, K14, CJ2, and CJ3 are closed. When the operating current reaches the series conversion condition, i.e., the series current is greater than 235A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors trip, circuit breaker QF closes, and the system enters series mode (e.g., Figure 6 (As shown).

[0036] The beneficial effects of this technical solution are as follows: I. This invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power regulation system. Simultaneous start-up of all six phases improves voltage regulation efficiency. A stepped voltage regulation system is set, eliminating the need for operator intervention during the voltage regulation process after parameter settings, thus reducing the risk of misoperation. The switching conditions for the four-pair breakdown maintenance switch to CJ3 or series connection can be set according to the highest voltage of the reduction transformer, effectively preventing connection failures. The high-voltage start-up uses a single-stage voltage boost, avoiding harmonics during the boost process that could cause thyristor mis-triggering and lead to circulating current short circuits. The voltage regulation logic eliminates the voltage regulation current setting; the same current is used for high-voltage start-up, reduction, and parallel connection, preventing insufficient current at the beginning of the voltage regulation phase from affecting furnace temperature rise and thus impacting voltage regulation efficiency.

[0037] II. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power adjustment system. By adjusting the connection layout of the pressure-pressuring cable on the furnace bottom electrode, the six phases can be started simultaneously, that is, the first two pairs of silicon cores of the 4-pair, 6-pair, and 8-pair systems can be broken down in a single step, thereby improving the overall pressure-pressuring efficiency.

[0038] III. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power regulation system. After 4 pairs of rods break down, the system directly switches to series connection. When the first 4 pairs of rods of the 6th and 8th pairs of rods simultaneously continue current, a situation arises where they cannot be connected. In the original voltage-pressurization program, i.e., the conditions for switching 4 pairs of rods to series connection are: the parallel and series currents are greater than or equal to the set restoration current of 50A, K23, K14, and CJ3 are opened, and QF is closed. The conditions for switching 4 pairs of rods to series connection are modified so that the parallel and series currents are greater than or equal to the set restoration current of 50A and the restoration voltage plus the parallel voltage is less than 2300V. For the 6th and 8th pairs of rods, the voltage judgment for switching from CJ2 to CJ3 after the 3rd and 4th pairs of rods break down is added to the voltage-pressurization program (i.e., when the parallel voltage plus the series voltage is less than 2300V and the parallel and series currents are greater than or equal to the set restoration current of 50A after the 3rd and 4th pairs of rods break down), switching to CJ3 to continue current, ensuring that the broken silicon core can be successfully connected to the restoration current.

[0039] IV. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair polycrystalline silicon power regulation system. A stepped voltage is added to the pressure-up process. When the first pair is pressure-up, due to the high silicon core resistance, the first stepped voltage can be set to 9000V (the given voltage for power regulation system startup is automatically set to 9000V). When the second, third, and fourth pairs are pressure-up, because the first pair of silicon cores has broken down and the furnace temperature has increased, the silicon core resistance has decreased, so the second stepped voltage can be set to 7000V (by judging that the first pair of silicon cores has entered the freewheeling stage, i.e., 0V < series voltage < 700V, series current 50A). Similarly, after pressure-up of the 5th, 6th, 7th, and 8th pairs, the third stepped voltage is set to 4000V (1500V < reduction voltage < 2650V, series current 50A). After setting the parameters, no manual voltage modification is required during the pressure-up process, achieving one-button start-up.

[0040] V. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system. In the pressure-up logic, the pressure-up given current 1 is canceled. The same restoration given current is recognized for high-voltage start-up, restoration, and parallel connection. The switching conditions for entering the maintenance state are the pressure-up current value, the maintenance parallel current, the series current during freewheeling, and the series current in the series mode. This avoids the current being too small at the beginning of the pressure-up stage, which affects the furnace temperature rise and thus the pressure-up efficiency.

[0041] VI. The present invention provides an automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system. The high-voltage start-up adopts a single-stage voltage boost, that is, the power regulation system adjusts the primary side voltage of the voltage-reducing transformer by the phase shift trigger of the thyristor at the 2650V stage of the reduction transformer to achieve breakdown control of the high voltage output of the silicon core, thus avoiding the harmonics in the stacked voltage regulation boost process that cause the thyristor to be falsely triggered and form a circulating current short circuit.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system, characterized in that, The steps include: high-voltage startup methods for 4-pair silicon cores, 6-pair silicon cores, and 8-pair silicon cores; The high-voltage start-up method for the four pairs of silicon core rods includes four pairs of silicon core rod breakdown, four pairs of silicon core rod maintenance, and four pairs of silicon core rod freewheeling. The high-voltage start-up method for the six pairs of silicon core rods includes six pairs of silicon core rod breakdown, six pairs of silicon core rod maintenance, and six pairs of silicon core rod freewheeling. The high-voltage start-up method for the 8 pairs of silicon core rods is as follows: the breakdown process of silicon cores R1, R2, R3, and R4 is the same as that of the 6 pairs of silicon core rods; R5 and R6 are boosted through a voltage-pressurizing transformer. After the silicon core breaks down, the voltage-pressurizing current is greater than or equal to 50A and the voltage-pressurizing voltage is less than 4000V. R5 and R6 await heating; then R7 and R8 are broken down, with a breakdown current greater than or equal to 50A and a breakdown voltage less than 4000V, and R7 and R8 are maintained for heating. When the maintenance current of R7 and R8, i.e., the parallel current, is greater than or equal to the restoration given current of 50A, the polycrystalline silicon power control system maintains heating for R5 and R6. When the parallel current is greater than or equal to 50A, K13 trips, and the polycrystalline silicon power control system maintains heating for R5, R6, R7, and R8 simultaneously. When the parallel current is greater than or equal to the restoration given current of 50A, the polycrystalline silicon power control system enters parallel mode. When the operating current reaches the series conversion condition, i.e., the series current is greater than 235A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors trip, and the polycrystalline silicon power control system enters series mode. It also includes data settings: First, set the restoration given current to 50A, set the first step voltage for voltage reduction: the given voltage when R1 is applied is 9000V, set the second step voltage for voltage reduction: the given voltage when R2, R3, and R4 are applied is 7000V, set the third step voltage for voltage reduction: the given voltage when R5, R6, R7, and R8 are applied is 4000V, and switch the holding voltage to 4000V. The four pairs of silicon core rods are broken down: the power regulator starts the four pairs of rods to break down. K21 vacuum contactor closes, K11 contactor closes, CJ1 closes. When the high voltage starts, the system adjusts the primary side voltage of the voltage-suppressing transformer through the phase shift trigger of the thyristor to achieve high voltage control of the silicon core output to break down. After the silicon core breaks down, the voltage-suppressing transformer is activated. The primary-secondary ratio of the voltage-suppressing transformer is 1:3.

5. The primary side voltage-suppressing current is detected by CT7 and rises to the conversion condition greater than the set restoration current of 50A.

2. The automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system according to claim 1, characterized in that: The four pairs of silicon core rods are maintained as follows: when the voltage is less than 4000V, the circuit can be switched to the maintenance heating stage. During the maintenance heating stage, the silicon core current, i.e. the current in parallel, increases from 0A to 50A. The silicon core current is detected by CT7. CJ1 is opened and CJ2 is closed.

3. The automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system according to claim 2, characterized in that: The four pairs of silicon core freewheeling circuits are as follows: When the silicon core current, i.e., the parallel current detected by CT7, is greater than or equal to 50A, the system enters the restoration freewheeling stage. The restoration freewheeling stage refers to maintaining the silicon core current through the restoration series circuit. CJ2 trips, K11 trips, and CJ3 closes. When the silicon core current, i.e., the series current, is equal to 50A, the system enters the freewheeling stage. The freewheeling stage refers to maintaining the silicon core current at 50A through the series circuit. Similarly, the silicon cores R2 and R3 are broken down. When the silicon core R4 breaks down and enters the maintenance stage with a parallel current of 50A, a voltage judgment is added to ensure successful series switching. That is, the sum of the series voltage of R1, R2, and R3 and the parallel voltage of R4 is less than the set series switching voltage of the four pairs of rods, 2300V. At this time, K23, K14, and CJ3 trip, the circuit breaker QF closes, and the system enters the series mode.

4. The automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system according to claim 3, characterized in that: The breakdown of the 6 pairs of silicon core rods: K21 vacuum contactor closes, K11 contactor closes, CJ1 closes. During high-voltage startup, the system adjusts the primary voltage of the voltage-suppressing transformer through thyristor phase shift triggering to achieve high-voltage control of the silicon core output to cause breakdown. After the silicon core breaks down, the voltage-suppressing transformer is activated. The primary-secondary ratio of the voltage-suppressing transformer is 1:3.

5. The primary voltage-suppressing current is detected by CT7 and rises to the conversion condition greater than or equal to the set restoration current of 50A.

5. The automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system according to claim 4, characterized in that: The six pairs of silicon core rods are maintained as follows: when the voltage is less than 4000V, the circuit can be switched to the heating stage, CJ1 is opened and CJ2 is closed.

6. The automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system according to claim 5, characterized in that: The six pairs of silicon core freewheeling circuits: When the silicon core current, i.e., the parallel current, is greater than or equal to 50A, the circuit enters the restoration freewheeling stage. The restoration freewheeling stage refers to maintaining the silicon core current through the restoration series circuit. CJ2 trips, K11 trips, and CJ3 closes. When the silicon core current, i.e., the series current at this time, is greater than or equal to 50A, the circuit enters freewheeling. Similarly, silicon cores R2, R3, and R4 are broken down. When R3 and R4 break down, the maintaining current, i.e., the parallel current, is greater than or equal to the set restoration current of 50A, and the series voltage plus the parallel voltage is less than 2300V, CJ...

2. When K22 is tripped, K23 and CJ3 are closed to provide freewheeling current to R1, R2, R3 and R4. When K14 and CJ1 are closed, R5-R6 are broken down. Similarly, when the holding current of R5 and R6, i.e. the parallel current, is greater than or equal to 50A, the system enters parallel mode. At this time, CJ2, CJ3, K23 and K14 are in the closed state. When the series voltage plus the parallel voltage is less than 2300V and the series current is greater than 140A, K23, K14, CJ2 and CJ3 are tripped, circuit breaker QF is closed, and the system enters series operation mode.

7. The automatic high-voltage start-up method for a six-phase 40-pair rod polycrystalline silicon power regulation system according to claim 6, characterized in that: The breakdown process of silicon cores R1, R2, R3, and R4 is the same as the breakdown process of the 6-pair silicon cores. R5 and R6 are stepped up by the voltage transformer. After K22, K13, and CJ1 are closed, the voltage surge current is greater than or equal to 50A and the voltage surge voltage is less than 4000V. K13 and K22 are then opened, and R5 and R6 await heating. K23 and K14 are then closed to initiate the breakdown of R7 and R8. The voltage surge current is greater than or equal to 50A and the voltage surge voltage is less than 4000V. CJ1 is then opened, and CJ2 is closed to maintain the heating of R7 and R8. When the maintenance current (parallel current) of R7 and R8 is greater than or equal to the restoration current of 50A, K23 and K14 are then opened. When K13 and K22 are closed, the system maintains heating for R5 and R6. When the parallel current is greater than or equal to 50A, K13 opens and K14 closes, and the system simultaneously maintains heating for R5, R6, R7, and R8, maintaining the silicon core current of R5, R6, R7, and R8, i.e., the parallel current, to reach 50A. When the parallel current is greater than or equal to the restoration given current of 50A, the system enters parallel mode, at which time K22, K14, CJ2, and CJ3 are in the closed state. When the operating current reaches the series conversion condition, i.e., the series current is greater than 235A and the sum of the parallel voltage and the series voltage is less than 2300V, all contactors open and circuit breaker QF closes, and the system enters series mode.

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