A control method and system for a powder feeder based on redundancy switching

Abstract

This invention provides a control method and system for a powder feeder based on redundancy switching in the field of industrial automation control technology. The method includes: step S10, acquiring the real-time output frequency analog signal of the main motor of the powder feeder, and converting the frequency analog signal into a corresponding high-speed pulse signal P_plus2 through a signal transformation algorithm; step S20, acquiring the original high-speed pulse signal P_plus1 collected from the main motor by a speed sensor in real time, and judging the state of P_plus1 and P_plus2 in real time; based on a preset switching logic, when P_plus1 is determined to be in a fault state, the speed feedback signal is seamlessly switched from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder. The advantages of this invention are: it greatly improves the fault tolerance of the powder feeder, avoids machine shutdown when a single point of failure occurs in the speed detection stage, and ensures continuous and stable production operation.

Description

Technical Field

[0001] This invention relates to the field of industrial automation control technology, and in particular to a control method and system for a powder feeder based on redundancy switching. Background Technology

[0002] The powder feeder control system is a key piece of equipment in industrial sectors such as textiles, food processing, and thermal power, where a stable supply of powder materials is required. This system is primarily responsible for the continuous and precise delivery of powder materials to downstream equipment such as grinding mills. Its core function is to adjust the powder feed rate in real time based on the load demands of the downstream equipment. Therefore, the continuity and stability of the feeder system's operation directly affect the production efficiency and operational reliability of the entire raw material grinding or processing system.

[0003] Early powder feeder control systems often used packaged circuit boards or integrators combined with electrical circuits, which were outdated technologies and whose functional expandability and adaptability could hardly meet the complex and ever-changing needs of modern industrial sites. Currently, some manufacturers have upgraded their control systems by using programmable devices such as programmable logic controllers (PLCs), which makes the system's logic control more flexible and facilitates functional expansion and program updates.

[0004] However, existing control schemes still suffer from a significant reliability bottleneck: the single-point failure problem of speed sensors. Current systems generally only utilize a single speed sensor (such as a tachogenerator) to detect the feeder motor's rotational speed. This speed signal is fundamental for the control system to calculate key parameters such as instantaneous feed rate and cumulative feed volume. If this speed sensor fails, or if its wiring or other issues cause the speed signal to be lost, the control system will be unable to obtain effective speed feedback. This will directly lead to the calculated feed rate becoming zero, triggering the system's protection logic and causing the feeder to trip and shut down. This unplanned shutdown not only interrupts the powder feeding process but may also have a cascading effect on downstream grinding mills and even the stable operation of the entire unit or production line, causing production interruptions and economic losses.

[0005] Therefore, how to provide a control method and system for powder feeders based on redundancy switching to improve the fault tolerance of powder feeders, avoid machine tripping when a single point of failure occurs in the speed detection stage, and ensure continuous and stable production operation has become an urgent technical problem to be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a control method and system for a powder feeder based on redundancy switching, so as to improve the fault tolerance of the powder feeder, avoid machine tripping when a single point of failure occurs in the speed detection stage, and ensure continuous and stable operation of production.

[0007] In a first aspect, the present invention provides a powder feeder control method based on redundancy switching, comprising the following steps: Step S10: Obtain the real-time output frequency analog signal of the main motor of the powder feeder, and convert the frequency analog signal into the corresponding high-speed pulse signal P_plus2 through a signal conversion algorithm; Step S20: Acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and determine the status of P_plus1 and P_plus2 in real time; based on the preset switching logic, when P_plus1 is determined to be in a fault state, seamlessly switch the speed feedback signal from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder.

[0008] Furthermore, step S10 specifically includes: Step S11: Obtain the real-time output frequency analog signal f of the main motor of the powder feeder; Step S12: Calculate the theoretical output speed n of the main motor based on the number of pole pairs P of the main motor: n = 60 * f / P; Step S13: Obtain the rotational speed calculation period T_cycle and the number of teeth C of the main motor drive gear. Based on the theoretical output rotational speed n, the rotational speed calculation period T_cycle, and the number of teeth C, transform the frequency analog signal f into the corresponding high-speed pulse signal P_plus2. P_plus2=n*C / 60 / (T_cycle / 1000); The unit of the rotational speed calculation period T_cycle is milliseconds.

[0009] Furthermore, in step S10, the frequency analog signal is taken from the frequency output terminal of the inverter driving the main motor, and the signal type is a 4~20mA current signal.

[0010] Furthermore, step S20 specifically includes: Step S21: Real-time acquisition of the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor, and continuous monitoring of the status of P_plus1 and P_plus2; Step S22: When the state of P_plus1=0 and P_plus2≠0 continues for a preset switching judgment time T, the speed sensor is determined to be faulty, and a switching operation is performed to seamlessly switch the speed feedback signal from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder; otherwise, the speed feedback signal continues to maintain P_plus1.

[0011] Furthermore, in step S22, the switching determination time T must be less than the delay tripping time T0 after the speed feedback signal is lost, i.e., T <T0。 Secondly, the present invention provides a powder feeder control system based on redundancy switching, comprising the following modules: The signal conversion module is used to acquire the real-time output frequency analog signal of the main motor of the powder feeder, and convert the frequency analog signal into the corresponding high-speed pulse signal P_plus2 through the signal conversion algorithm. The signal redundancy switching module is used to acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and to judge the status of P_plus1 and P_plus2 in real time. Based on the preset switching logic, when P_plus1 is determined to be in a fault state, the speed feedback signal is seamlessly switched from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder.

[0012] Furthermore, the signal conversion module specifically includes: The frequency analog signal acquisition unit is used to acquire the real-time frequency analog signal f output by the main motor of the powder feeder; The theoretical output speed calculation unit is used to calculate the theoretical output speed n of the main motor based on the number of pole pairs P of the main motor. n = 60 * f / P; A high-speed pulse signal calculation unit is used to obtain the rotational speed calculation period T_cycle and the number of teeth C of the main motor drive gear. Based on the theoretical output rotational speed n, rotational speed calculation period T_cycle, and number of teeth C, the frequency analog signal f is transformed into the corresponding high-speed pulse signal P_plus2. P_plus2=n*C / 60 / (T_cycle / 1000); The unit of the rotational speed calculation period T_cycle is milliseconds.

[0013] Furthermore, in the signal conversion module, the frequency analog signal is taken from the frequency output terminal of the inverter driving the main motor, and the signal type is a 4~20mA current signal.

[0014] Furthermore, the signal redundancy switching module specifically includes: The signal monitoring unit is used to acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and to continuously monitor the status of P_plus1 and P_plus2. The signal switching unit is used to determine that the speed sensor is faulty when the state of P_plus1=0 and P_plus2≠0 continues for a preset switching judgment time T, and to perform a switching operation to seamlessly switch the speed feedback signal from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder; otherwise, the speed feedback signal continues to maintain P_plus1.

[0015] Furthermore, in the signal switching unit, the switching determination time T must be less than the delay tripping time T0 after the speed feedback signal is lost, i.e., T <T0。

[0016] The advantages of this invention are: 1. The system acquires the real-time frequency analog signal output from the main motor of the powder feeder and transforms it into a corresponding high-speed pulse signal P_plus2 using a signal transformation algorithm. Then, it acquires the original high-speed pulse signal P_plus1 collected from the main motor by a speed sensor in real time and determines the status of P_plus1 and P_plus2 in real time. Based on a preset switching logic, when P_plus1 is determined to be in a fault state, the speed feedback signal is seamlessly switched from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder. This is achieved by constructing a dual-path speed feedback channel with one main and one backup: while retaining the original speed sensor (main channel), a backup speed pulse signal (backup channel) is innovatively calculated in real time from the frequency analog signal of the main motor. When the main channel signal is continuously lost while the backup channel signal is normal, the speed feedback is automatically and seamlessly switched to the backup channel before the protection trip timeout. This ensures continuous and stable control based on speed feedback even when a single point of failure occurs in the speed sensor, effectively avoiding unplanned downtime and guaranteeing production continuity.

[0017] 2. Two speed feedback signal channels, a main channel and a backup channel, have been established. When the main channel (P_plus1 generated by the physical speed sensor) fails, the system can automatically and quickly switch the control feedback source to the backup channel (P_plus2 generated by the algorithm transformation of the main motor frequency signal) based on preset and rigorous logical judgment conditions. This "seamless switching" mechanism ensures that the control system will not malfunction or stop due to the loss of feedback signal at the moment of sensor failure, thereby maintaining the continuous and stable operation of the powder feeder and even the entire production process, greatly improving the availability and production reliability of the system, and avoiding losses caused by unplanned downtime.

[0018] 3. The generation of the backup signal P_plus2 is not a simple replacement, but is based on the drive source (the inverter frequency analog signal) and is accurately calculated using an algorithm that includes key mechanical parameters such as the number of motor pole pairs and the number of gear teeth. This ensures that the backup signal can highly reflect the actual operating speed of the motor, laying the foundation for continuous and accurate control after switching. At the same time, the switching logic (such as the determination of the duration T when P_plus1=0 and P_plus2≠0) is cleverly designed, effectively distinguishing between "real faults" and "instantaneous interference" and preventing false switching. In particular, the switching determination time T is limited to be less than the system trip time T0, ensuring that the system can complete the switching before the protection action, reflecting the design concept of active fault tolerance, and further ensuring the safety and accuracy of the control process.

[0019] 4. Compared to the approach of directly shutting down or handling large fluctuations after a fault, the seamless switching achieves "fault non-sensory" operation. When a critical fault such as the failure of the speed sensor occurs, the control system can still obtain continuous and effective speed feedback, thereby enabling the control loop (such as speed closed loop and feed rate control) to remain stable. This avoids problems such as sudden changes in feed rate and equipment vibration caused by feedback interruption, which directly ensures the proportioning accuracy and quality stability of the final product (such as batch material) and optimizes the dynamic response performance of the entire system.

[0020] 5. By optimizing the algorithm program of the controller (such as PLC or dedicated controller), there is no need to make significant changes to the existing hardware architecture (such as frequency converter or motor) or add expensive redundant sensor hardware; the backup signal is directly taken from the existing output of the frequency converter, making full use of the existing signal resources; this design concept of "using software algorithm to make up for the shortcomings of hardware reliability" significantly improves the system reliability and continuous operation capability while effectively controlling hardware costs and reducing the complexity of later maintenance and spare parts inventory pressure.

[0021] 6. By monitoring and comparing the status of two signals in real time, the system actively judges the health status of the sensors and autonomously executes the optimal response strategy (seamless switching) when a fault occurs, demonstrating the intelligent evolution of the control system from "fault handling" to "fault prevention and adaptation". It converts easily obtainable analog signals into digital pulse signals that can be used in high-speed control loops through a precise model, demonstrating good system integration and information fusion capabilities. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a flowchart of a powder feeder control method based on redundancy switching according to the present invention.

[0024] Figure 2This is a schematic diagram of the structure of a powder feeder control system based on redundancy switching according to the present invention.

[0025] Figure 3 This is a hardware architecture diagram of the present invention.

[0026] Figure 4 This is a schematic diagram of signal switching according to the present invention. Detailed Implementation

[0027] The overall concept of the technical solution in this application embodiment is as follows: a dual-channel speed feedback system with one main and one backup is constructed through software algorithms; specifically, while retaining the original physical speed sensor (main channel P_plus1), a backup high-speed pulse signal (backup channel P_plus2) is innovatively calculated in real time from the analog frequency signal of the inverter driving the main motor; the status of the two signals is continuously monitored and compared, and when it is determined that the main channel has failed (such as continuous signal loss) while the backup channel signal is normal, the speed feedback source will be automatically and seamlessly switched to the backup channel in a very short time before the system protection trips, so that the feeder can still maintain continuous and stable operation when a single point of failure occurs in the speed measurement link, effectively avoiding unplanned shutdowns.

[0028] Please refer to Figures 1 to 4 As shown, a preferred embodiment of the powder feeder control method based on redundancy switching of the present invention includes the following steps: Step S10: Obtain the real-time output frequency analog signal of the main motor of the powder feeder, and convert the frequency analog signal into the corresponding high-speed pulse signal P_plus2 through a signal conversion algorithm; Step S20: Acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and determine the status of P_plus1 and P_plus2 in real time; based on the preset switching logic, when P_plus1 is determined to be in a fault state, seamlessly switch the speed feedback signal from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder.

[0029] The main channel signal P_plus1 originates from a physical speed sensor (such as a photoelectric encoder or magnetoelectric proximity switch) directly mounted on the main motor, and is a direct measurement of the motor's actual speed. The backup channel signal P_plus2, on the other hand, originates from the frequency analog signal (typically a 4-20mA current signal) output by the inverter driving the main motor. This signal represents the power frequency that the inverter expects to apply to the motor, and is the root cause of the motor speed command. Although the two signals originate from different sources (one from measurement feedback, the other from a drive command), a precise algorithm model can reliably convert the frequency command f into an equivalent speed pulse signal. This "heterogeneous redundancy" design makes the failure modes of the backup channel essentially independent of those of the main channel (sensor failure, line interruption, etc.), greatly improving the overall fault tolerance of the system in the speed detection stage.

[0030] Step S10 specifically includes: Step S11: Obtain the real-time output frequency analog signal f of the main motor of the powder feeder; Step S12: Calculate the theoretical output speed n of the main motor based on the number of pole pairs P of the main motor: n = 60 * f / P; The formula n=60*f / P is the fundamental formula for the synchronous speed of an AC asynchronous motor. Here, the frequency f (Hz) is output by the frequency converter, and the number of pole pairs P is an inherent parameter of the main motor. This step converts the frequency command from the electrical control system into the theoretical synchronous speed (r / min) of the motor shaft. Considering that the powder feeder typically operates near its rated load, with a relatively stable and small slip rate, this theoretical speed can highly approximate the actual output speed of the main motor.

[0031] Step S13: Obtain the rotational speed calculation period T_cycle and the number of teeth C of the main motor drive gear. Based on the theoretical output rotational speed n, the rotational speed calculation period T_cycle, and the number of teeth C, transform the frequency analog signal f into the corresponding high-speed pulse signal P_plus2. P_plus2=n*C / 60 / (T_cycle / 1000); The unit of the rotational speed calculation period T_cycle is milliseconds.

[0032] The meaning of n*C / 60 is: when the main motor rotates at a speed of n (revolutions per minute), the gear with C teeth mounted on its shaft sweeps n*C teeth per minute. Dividing by 60 gives the theoretical number of pulses per second (Hz), which simulates the pulse frequency that a speed sensor (such as a proximity switch detecting gears) should generate under ideal conditions.

[0033] The reason for dividing by (T_cycle / 1000) is that in digital controllers (such as PLCs), speed sampling and calculation are usually performed in a fixed calculation cycle T_cycle (unit: milliseconds). Multiplying the "number of pulses per second" by the "number of seconds corresponding to each calculation cycle" (i.e., T_cycle / 1000) yields the theoretical number of high-speed pulses that should be received in each calculation cycle T_cycle. This value (P_plus2) is completely consistent with the original pulse signal P_plus1 (the actual number of pulses collected in each cycle) from the real sensor in both numerical format and physical meaning, thus creating a prerequisite for subsequent state comparison and seamless switching.

[0034] The calculation of the backup pulse signal P_plus2 is not a simple proportional conversion, but a model derivation based on the principles of electrical machinery and mechanical transmission relationships; its calculation process reflects the complete mapping from "electrical command" to "mechanical speed" and then to "equivalent pulse".

[0035] In step S10, the frequency analog signal is taken from the frequency output terminal of the inverter driving the main motor, and the signal type is a 4~20mA current signal.

[0036] Step S20 specifically includes: Step S21: Real-time acquisition of the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor, and continuous monitoring of the status of P_plus1 and P_plus2; Step S22: When the state of P_plus1=0 and P_plus2≠0 continues for a preset switching judgment time T, the speed sensor is determined to be faulty, and a switching operation is performed to seamlessly switch the speed feedback signal (P_plus) from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder, i.e., P_plus=P_plus2; otherwise, the speed feedback signal continues to maintain P_plus1, i.e., P_plus=P_plus1.

[0037] In step S22, the switching determination time T must be less than the delay tripping time T0 after the speed feedback signal is lost, i.e., T <T0。

[0038] The decision condition P_plus1=0 and P_plus2≠0 has a duration of T and involves multiple considerations: Anti-interference capability: The fault state (P_plus1=0) is required to last for a preset time T, which can effectively filter out the instantaneous loss of pulse signals caused by electromagnetic interference, instantaneous mechanical vibration, etc., and prevent erroneous switching.

[0039] Fault confirmation: At the same time, it is required that the signal P_plus2 of the standby channel is normal (P_plus2 ≠ 0), which is a crucial interlock condition. It indicates that the main motor is indeed running (the frequency converter has frequency output), thus confirming that the disappearance of P_plus1 is due to a fault in the sensor or its loop itself, rather than equipment shutdown. This avoids misoperation under normal operating conditions such as equipment startup and shutdown.

[0040] Preemptive switching to ensure continuity: The constraint condition T < TO (TO is the delay tripping protection time after the loss of the speed feedback signal of the control system) is the essence of this invention. It ensures that once a real sensor fault occurs, the control system can complete fault determination and signal source switching (from P_plus1 to P_plus2) before the protection shutdown timer (TO) is triggered. This enables the speed feedback loop of the controller to restore an effective signal before the protection system senses a "signal fault", thus completely avoiding tripping triggered by this single-point fault and achieving a truly "seamless" and "disturbance-free" switch.

[0041] A preferred embodiment of a powder feeder control system based on redundant switching according to this invention includes the following modules: A signal conversion module, which is used to obtain the frequency analog signal output in real time by the main motor of the powder feeder, and through a signal conversion algorithm, convert the frequency analog signal into a corresponding high-speed pulse signal P_plus2; A signal redundant switching module, which is used to obtain the original high-speed pulse signal P_plus1 collected from the main motor by the speed measurement sensor in real time, and judge the states of P_plus1 and P_plus2 in real time; based on a preset switching logic, when P_plus1 is determined to be in a fault state, seamlessly switch the speed feedback signal from P_plus1 to P_plus2 to maintain the disturbance-free operation of the powder feeder.

[0042] The main channel signal P_plus1 comes from a physical speed measurement sensor directly installed on the main motor (such as an optical encoder, a magnetoelectric proximity switch, etc.), and is a direct measurement value of the actual speed of the motor. The standby channel signal P_plus2 comes from the frequency analog signal output by the frequency converter driving the main motor (usually a 4 - 20 mA current signal), which represents the power frequency that the frequency converter expects to apply to the motor and is the instruction source of the motor speed. Although their sources are different (one is measurement feedback and the other is drive instruction), through an accurate algorithm model, the frequency instruction f can be reliably converted into an equivalent speed pulse signal. This "heterogeneous redundancy" design makes the failure mode of the standby channel basically independent of the main channel (sensor fault, circuit interruption, etc.), greatly enhancing the overall fault tolerance of the system in the speed detection link.

[0043] The signal conversion module specifically includes: The frequency analog signal acquisition unit is used to acquire the real-time frequency analog signal f output by the main motor of the powder feeder; The theoretical output speed calculation unit is used to calculate the theoretical output speed n of the main motor based on the number of pole pairs P of the main motor. n = 60 * f / P; The formula n=60*f / P is the fundamental formula for the synchronous speed of an AC asynchronous motor. Here, the frequency f (Hz) is output by the frequency converter, and the number of pole pairs P is an inherent parameter of the main motor. This step converts the frequency command from the electrical control system into the theoretical synchronous speed (r / min) of the motor shaft. Considering that the powder feeder typically operates near its rated load, with a relatively stable and small slip rate, this theoretical speed can highly approximate the actual output speed of the main motor.

[0044] A high-speed pulse signal calculation unit is used to obtain the rotational speed calculation period T_cycle and the number of teeth C of the main motor drive gear. Based on the theoretical output rotational speed n, rotational speed calculation period T_cycle, and number of teeth C, the frequency analog signal f is transformed into the corresponding high-speed pulse signal P_plus2. P_plus2=n*C / 60 / (T_cycle / 1000); The unit of the rotational speed calculation period T_cycle is milliseconds.

[0045] The meaning of n*C / 60 is: when the main motor rotates at a speed of n (revolutions per minute), the gear with C teeth mounted on its shaft sweeps n*C teeth per minute. Dividing by 60 gives the theoretical number of pulses per second (Hz), which simulates the pulse frequency that a speed sensor (such as a proximity switch detecting gears) should generate under ideal conditions.

[0046] The reason for dividing by (T_cycle / 1000) is that in digital controllers (such as PLCs), speed sampling and calculation are usually performed in a fixed calculation cycle T_cycle (unit: milliseconds). Multiplying the "number of pulses per second" by the "number of seconds corresponding to each calculation cycle" (i.e., T_cycle / 1000) yields the theoretical number of high-speed pulses that should be received in each calculation cycle T_cycle. This value (P_plus2) is completely consistent with the original pulse signal P_plus1 (the actual number of pulses collected in each cycle) from the real sensor in both numerical format and physical meaning, thus creating a prerequisite for subsequent state comparison and seamless switching.

[0047] The calculation of the backup pulse signal P_plus2 is not a simple proportional conversion, but a model derivation based on the principles of electrical machinery and mechanical transmission relationships; its calculation process reflects the complete mapping from "electrical command" to "mechanical speed" and then to "equivalent pulse".

[0048] In the signal conversion module, the frequency analog signal is taken from the frequency output terminal of the inverter driving the main motor, and the signal type is a 4~20mA current signal.

[0049] The signal redundancy switching module specifically includes: The signal monitoring unit is used to acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and to continuously monitor the status of P_plus1 and P_plus2. The signal switching unit is used to determine that the speed sensor is faulty when the state of P_plus1=0 and P_plus2≠0 continues for a preset switching judgment time T. Then, it performs a switching operation to seamlessly switch the speed feedback signal (P_plus) from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder, i.e., P_plus=P_plus2; otherwise, the speed feedback signal continues to maintain P_plus1, i.e., P_plus=P_plus1.

[0050] In the signal switching unit, the switching determination time T must be less than the delay trip time T0 after the speed feedback signal is lost, i.e., T <T0。

[0051] The decision condition P_plus1=0 and P_plus2≠0 has a duration of T and involves multiple considerations: Anti-interference capability: The fault state (P_plus1=0) is required to last for a preset time T, which can effectively filter out the instantaneous loss of pulse signals caused by electromagnetic interference, instantaneous mechanical vibration, etc., and prevent erroneous switching.

[0052] Fault Confirmation: Simultaneously, the backup channel signal P_plus2 must be normal (P_plus2≠0), a crucial interlock condition. This indicates that the main motor is indeed running (the inverter has frequency output), thus confirming that the disappearance of P_plus1 is due to a fault in the sensor or its circuit itself, rather than a equipment shutdown. This prevents erroneous actions during normal operating conditions such as equipment start-up and shutdown.

[0053] Preemptive switching ensures continuity: The constraint condition T < TO (TO is the delay tripping protection time after the loss of the speed feedback signal of the control system) is the essence of this invention. It ensures that once a real sensor fault occurs, the control system can complete the fault determination and signal source switching (from P_plus1 to P_plus2) before the protection shutdown timer (TO) is triggered. This enables the speed feedback loop of the controller to restore the effective signal before the protection system senses a "signal fault", thus completely avoiding the tripping triggered by this single-point fault and achieving a truly "seamless" and "perturbation-free" switching.

[0054] In summary, the advantages of this invention are as follows: 1. By obtaining the frequency analog signal of the real-time output of the main motor of the powder feeder and transforming it into the corresponding high-speed pulse signal P_plus2 through a signal transformation algorithm; then, the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor is obtained in real time, and the states of P_plus1 and P_plus2 are judged in real time; based on the preset switching logic, when P_plus1 is judged to be in a fault state, the speed feedback signal is seamlessly switched from P_plus1 to P_plus2 to maintain the perturbation-free operation of the powder feeder; that is, the fault tolerance ability is improved by constructing a "one main and one standby" dual-channel speed feedback channel: while retaining the original speed sensor (main channel), the standby speed pulse signal (standby channel) is innovatively calculated in real time from the frequency analog signal of the main motor; when the main channel signal is continuously detected to be lost while the standby channel signal is normal, the speed feedback will be automatically and seamlessly switched to the standby channel before the time limit for causing protection tripping, so that when a single-point fault occurs in the speed sensor, the continuous and stable control based on speed feedback can still be maintained, effectively avoiding unplanned shutdowns and ensuring the continuity of production.

[0055] 2. Two speed feedback signal channels, the main and the standby, are established; when the main channel (P_plus1 generated by the physical speed sensor) fails, the system can automatically and quickly switch the control feedback source to the standby channel (P_plus2 generated by transforming the main motor frequency signal through an algorithm) based on the preset and strict logic judgment conditions. This "seamless switching" mechanism ensures that at the moment of sensor failure, the control system will not malfunction or shut down due to the loss of the feedback signal, thus maintaining the continuous and stable operation of the powder feeder and even the entire production process, greatly improving the availability and production reliability of the system and avoiding the losses caused by unplanned shutdowns.

[0056] 3. The generation of the backup signal P_plus2 is not a simple replacement, but is based on the drive source (the inverter frequency analog signal) and is accurately calculated using an algorithm that includes key mechanical parameters such as the number of motor pole pairs and the number of gear teeth. This ensures that the backup signal can highly reflect the actual operating speed of the motor, laying the foundation for continuous and accurate control after switching. At the same time, the switching logic (such as the determination of the duration T when P_plus1=0 and P_plus2≠0) is cleverly designed, effectively distinguishing between "real faults" and "instantaneous interference" and preventing false switching. In particular, the switching determination time T is limited to be less than the system trip time T0, ensuring that the system can complete the switching before the protection action, reflecting the design concept of active fault tolerance, and further ensuring the safety and accuracy of the control process.

[0057] 4. Compared to the approach of directly shutting down or handling large fluctuations after a fault, the seamless switching achieves "fault non-sensory" operation. When a critical fault such as the failure of the speed sensor occurs, the control system can still obtain continuous and effective speed feedback, thereby enabling the control loop (such as speed closed loop and feed rate control) to remain stable. This avoids problems such as sudden changes in feed rate and equipment vibration caused by feedback interruption, which directly ensures the proportioning accuracy and quality stability of the final product (such as batch material) and optimizes the dynamic response performance of the entire system.

[0058] 5. By optimizing the algorithm program of the controller (such as PLC or dedicated controller), there is no need to make significant changes to the existing hardware architecture (such as frequency converter or motor) or add expensive redundant sensor hardware; the backup signal is directly taken from the existing output of the frequency converter, making full use of the existing signal resources; this design concept of "using software algorithm to make up for the shortcomings of hardware reliability" significantly improves the system reliability and continuous operation capability while effectively controlling hardware costs and reducing the complexity of later maintenance and spare parts inventory pressure.

[0059] 6. By monitoring and comparing the status of two signals in real time, the system actively judges the health status of the sensors and autonomously executes the optimal response strategy (seamless switching) when a fault occurs, demonstrating the intelligent evolution of the control system from "fault handling" to "fault prevention and adaptation". It converts easily obtainable analog signals into digital pulse signals that can be used in high-speed control loops through a precise model, demonstrating good system integration and information fusion capabilities.

[0060] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A control method for a powder feeder based on redundancy switching, characterized in that: Includes the following steps: Step S10: Obtain the real-time output frequency analog signal of the main motor of the powder feeder, and convert the frequency analog signal into the corresponding high-speed pulse signal P_plus2 through a signal conversion algorithm; Step S20: Acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and determine the state of P_plus1 and P_plus2 in real time. Based on the preset switching logic, when P_plus1 is determined to be in a fault state, the speed feedback signal is seamlessly switched from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder.

2. The powder feeder control method based on redundancy switching as described in claim 1, characterized in that: Step S10 specifically includes: Step S11: Obtain the real-time output frequency analog signal f of the main motor of the powder feeder; Step S12: Calculate the theoretical output speed n of the main motor based on the number of pole pairs P of the main motor: n = 60 * f / P; Step S13: Obtain the rotational speed calculation period T_cycle and the number of teeth C of the main motor drive gear. Based on the theoretical output rotational speed n, the rotational speed calculation period T_cycle, and the number of teeth C, transform the frequency analog signal f into the corresponding high-speed pulse signal P_plus2. P_plus2=n*C / 60 / (T_cycle / 1000); The unit of the rotational speed calculation period T_cycle is milliseconds.

3. The powder feeder control method based on redundancy switching as described in claim 1, characterized in that: In step S10, the frequency analog signal is taken from the frequency output terminal of the inverter driving the main motor, and the signal type is a 4~20mA current signal.

4. The powder feeder control method based on redundancy switching as described in claim 1, characterized in that: Step S20 specifically includes: Step S21: Real-time acquisition of the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor, and continuous monitoring of the status of P_plus1 and P_plus2; Step S22: When the state of P_plus1=0 and P_plus2≠0 continues for a preset switching judgment time T, the speed sensor is determined to be faulty, and a switching operation is performed to seamlessly switch the speed feedback signal from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder; otherwise, the speed feedback signal continues to maintain P_plus1.

5. The powder feeder control method based on redundancy switching as described in claim 4, characterized in that: In step S22, the switching determination time T must be less than the delay tripping time T0 after the speed feedback signal is lost, i.e., T <T0。 6. A powder feeder control system based on redundancy switching, characterized in that: Includes the following modules: The signal conversion module is used to acquire the real-time output frequency analog signal of the main motor of the powder feeder, and convert the frequency analog signal into the corresponding high-speed pulse signal P_plus2 through the signal conversion algorithm. The signal redundancy switching module is used to acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and to determine the status of P_plus1 and P_plus2 in real time. Based on the preset switching logic, when P_plus1 is determined to be in a fault state, the speed feedback signal is seamlessly switched from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder.

7. The powder feeder control system based on redundancy switching as described in claim 6, characterized in that: The signal conversion module specifically includes: The frequency analog signal acquisition unit is used to acquire the real-time frequency analog signal f output by the main motor of the powder feeder; The theoretical output speed calculation unit is used to calculate the theoretical output speed n of the main motor based on the number of pole pairs P of the main motor. n = 60 * f / P; A high-speed pulse signal calculation unit is used to obtain the rotational speed calculation period T_cycle and the number of teeth C of the main motor drive gear. Based on the theoretical output rotational speed n, rotational speed calculation period T_cycle, and number of teeth C, the frequency analog signal f is transformed into the corresponding high-speed pulse signal P_plus2. P_plus2=n*C / 60 / (T_cycle / 1000); The unit of the rotational speed calculation period T_cycle is milliseconds.

8. The powder feeder control system based on redundancy switching as described in claim 6, characterized in that: In the signal conversion module, the frequency analog signal is taken from the frequency output terminal of the inverter driving the main motor, and the signal type is a 4~20mA current signal.

9. The powder feeder control system based on redundancy switching as described in claim 6, characterized in that: The signal redundancy switching module specifically includes: The signal monitoring unit is used to acquire the original high-speed pulse signal P_plus1 collected from the main motor by the speed sensor in real time, and to continuously monitor the status of P_plus1 and P_plus2. The signal switching unit is used to determine that the speed sensor is faulty when the state of P_plus1=0 and P_plus2≠0 continues for a preset switching judgment time T, and to perform a switching operation to seamlessly switch the speed feedback signal from P_plus1 to P_plus2 to maintain the uninterrupted operation of the powder feeder; otherwise, the speed feedback signal continues to maintain P_plus1.

10. The powder feeder control system based on redundancy switching as described in claim 9, characterized in that: In the signal switching unit, the switching determination time T must be less than the delay trip time T0 after the speed feedback signal is lost, i.e., T <T0。

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