Stirring motor control method and related products for immobilized enzyme production

Abstract

The present application discloses a stirring motor control method and related products for the production of immobilized enzymes, and relates to the field of motor control. The method includes: in the homogenization crushing and stirring stage, the stirring motor speed is increased to the third preset speed, and the speed-torque dual link control is adopted, and the torque command is calculated by using the corresponding control parameters for different speed sections; in the immobilization reaction stirring stage, the stirring motor speed is reduced to the fourth preset speed, and the rotor flux oriented control is adopted, and the q-axis current command is processed by low-pass filtering until the speed drops to zero. Through the scheme of the present application, the motor can be efficiently stirred in the whole process of immobilized enzyme production.

Description

Technical Field

[0001] The present application relates to the field of motor control, and in particular to a stirring motor control method and related products for the production of immobilized enzymes. Background Art

[0002] In the production process of immobilized enzymes, stirring plays a vital role in product quality. At present, the production of immobilized synthetic penicillin G acylase mainly includes three key links: fermentation, extraction and immobilization, and each link requires precise stirring control. In the fermentation stage, seed culture and engineered bacteria fermentation processes require uniform stirring to ensure bacterial growth; in the extraction stage, the stirring intensity during flocculation precipitation and purification directly affects the purity of the product; and in the immobilization stage, the slow stirring of the carrier and the enzyme solution determines the activity and stability of the final product.

[0003] The stirring devices widely used at present mainly have the following problems: First, the stirring intensity adjustment accuracy is insufficient. Most of them adopt a simple frequency conversion speed regulation method, which makes it difficult to achieve accurate speed control and cannot meet the differentiated requirements for stirring intensity in different process stages. Secondly, the stirring uniformity is poor, and dead corners are easily formed in large reactors, resulting in incomplete reaction or local over-stirring. Third, there is a lack of intelligent control means, and the stirring strategy cannot be automatically adjusted according to the process parameters, requiring frequent intervention by operators. Fourth, the energy consumption is high. Especially in large-scale production, the energy consumption of the stirring system constitutes an important cost factor. These technical problems seriously restrict the improvement of the production efficiency of immobilized enzymes. In the fermentation stage, improper stirring will affect the growth of bacteria and the expression level of enzymes; in the extraction stage, uneven stirring will reduce the purity and yield of the product; in the immobilization stage, deviations in stirring control are more likely to cause a significant loss of enzyme activity. This not only affects product quality, but also increases production costs. In addition, the maintenance cost of existing stirring equipment is high, and wearing parts are frequently replaced. The reliability and stability issues of the stirring system also increase the uncertainty of the production process and affect the consistency control of product quality. With the continuous improvement of product quality requirements in the biopharmaceutical industry, the limitations of traditional stirring devices are becoming increasingly prominent.

[0004] Therefore, there is an urgent need for a technical solution that enables the motor to perform efficient stirring throughout the entire process of immobilized enzyme production. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present application discloses a stirring motor control method and related products for the production of immobilized enzymes. The present application solves the technical problems that the prior art cannot meet the differentiated requirements for stirring intensity at different process stages.

[0006] The embodiment of the present application discloses a stirring motor control method for immobilized enzyme production, comprising: in the bacterial inoculation stirring stage, by calculating the control amount of the speed deviation and inputting it into the frequency converter, controlling the stirring motor to start to a first preset speed, and using the vector control of the permanent magnet synchronous motor to adjust the speed; in the fermentation and proliferation stirring stage, the stirring motor speed is increased to a second preset speed, a torque pre-compensation scheme is used to establish a torque estimation model, and the viscosity coefficient is calculated according to the fermentation time and the output is adjusted; in the homogenization and crushing stirring stage, the stirring motor speed is increased to a third preset speed, speed-torque dual-link control is adopted, and the torque command is calculated for different speed sections using corresponding control parameters; in the immobilization reaction stirring stage, the stirring motor speed is reduced to a fourth preset speed, rotor flux directional control is adopted, and the q-axis current command is processed by low-pass filtering until the speed drops to zero.

[0007] In a possible implementation, the control quantity of the speed deviation is calculated and input into the frequency converter, the stirring motor is controlled to start to a first preset speed, and the speed is adjusted by using the vector control of the permanent magnet synchronous motor, including: controlling the stirring motor to start to a preset speed, and controlling the starting current to be below a predetermined multiple of the rated current; using the speed deviation to calculate the control quantity, wherein the control quantity is composed of a steady-state term and a dynamic term, and the steady-state term is calculated according to the ratio of the target speed to the rated speed; the dynamic term is calculated according to the speed deviation and its integral, and the composite control quantity is input into the frequency converter to drive the motor; the speed regulation is achieved by the vector control of the permanent magnet synchronous motor, so that the speed fluctuation is controlled within a predetermined range.

[0008] In a possible implementation, the speed of the stirring motor is increased to a second preset speed, a torque pre-compensation scheme is used to establish a torque estimation model, the viscosity coefficient is calculated according to the fermentation time and the output is adjusted, including: increasing the speed of the stirring motor to the second preset speed, wherein the slope of the speed increase process is a predetermined value; adopting the torque pre-compensation scheme, establishing a torque estimation model according to the viscosity change law of the fermentation liquid; calculating the equivalent viscosity coefficient of the fermentation liquid according to the fermentation time, estimating the torque and adjusting the output in advance; when the radial vibration amplitude of the stirring shaft exceeds the predetermined value, reducing the speed to a predetermined value.

[0009] In a possible implementation, during the homogenization crushing and mixing stage, the speed of the stirring motor is increased to a third preset speed, and a speed-torque dual-link control scheme is adopted, and corresponding control parameters are used to calculate the torque command for different speed sections, including: increasing the speed of the stirring motor to a third preset speed, and adopting a speed-torque dual-link control scheme; using a piecewise linearization method to calculate the torque command according to the speed range, and corresponding control parameters are used for the low-speed section and the high-speed section respectively; the inner loop adopts current tracking control to adjust the nonlinear characteristics of the control parameters; when the stator temperature exceeds a predetermined value, reducing the speed to a predetermined value.

[0010] In a possible implementation, during the immobilization reaction stirring stage, the stirring motor speed is reduced to a fourth preset speed, rotor flux oriented control is adopted, and the q-axis current command is processed by low-pass filtering until the speed drops to zero, including: reducing the stirring motor speed to a fourth preset speed, adopting rotor flux oriented control; controlling the rotor flux vector to coincide with the d-axis, keeping the rotor flux modulus and the d-axis current at predetermined values; low-pass filtering the q-axis current command, and dynamically adjusting it according to the torque demand; controlling the three-phase winding current imbalance within a predetermined range, and finally reducing the speed to zero within a predetermined time.

[0011] In one possible implementation, a torque estimation model is established according to the variation law of the fermentation liquid viscosity, including: ,in, represents torque, represents the equivalent viscosity coefficient of the fermentation broth, Indicates the speed, represents the moment of inertia, represents the angular acceleration, Represents the damping coefficient.

[0012] In one possible implementation, the q-axis current command is low-pass filtered and dynamically adjusted according to the torque demand, including: ,in, Indicates the q-axis current command, represents the first filter time constant, represents the second filter time constant, represents the target torque, Represents the torque coefficient.

[0013] An embodiment of the present application also discloses a control system that applies the stirring motor control method as described in any of the above embodiments, including: a power supply unit, including a three-phase AC input terminal; a power conversion unit, including an active rectifier and an inverter connected through a DC bus, and the active rectifier is electrically connected to the power supply unit; a motor drive unit, including a permanent magnet synchronous motor, whose stator winding is electrically connected to the output terminal of the inverter, and a permanent magnet is mounted on the rotor surface; a feedback unit, including a position sensor, a current sensor and a temperature sensor, for collecting operating status parameters of the permanent magnet synchronous motor; and a control unit, including a dual DSP structure, configured with a space vector PWM modulation algorithm, a rotor flux orientation algorithm and a speed and torque dual closed-loop control algorithm, for controlling the operation of the permanent magnet synchronous motor according to the parameters collected by the feedback unit.

[0014] An embodiment of the present application also discloses a stirring motor control device for the production of immobilized enzymes, comprising: a processor, a memory, and a system bus; wherein the processor and the memory are connected via the system bus; the memory is used to store one or more programs, and the one or more programs include instructions, which, when executed by the processor, enable the processor to execute the method described in any one of the above embodiments.

[0015] In the stirring motor control method and related products for immobilized enzyme production disclosed above, the embodiments of the present application combine multi-stage stirring motor control strategies to enable the motor to perform efficient stirring in the entire process of immobilized enzyme production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic flow chart of a stirring motor control method for immobilized enzyme production disclosed in an embodiment of the present application;

[0018] Figure 2 A schematic block diagram of a stirring motor control system disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0019] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0020] Those skilled in the art can understand that the terms "first", "second" and the like in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor represent the necessary logical order between them. It should also be understood that in the embodiments of the present disclosure, "multiple" can refer to two or more, and "at least one" can refer to one, two or more. It should also be understood that for any component, data or structure mentioned in the embodiments of the present disclosure, in the absence of explicit limitation or contrary revelation given in the context, it can generally be understood as one or more. In addition, the term "and / or" in the present disclosure is only a description of the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present disclosure generally indicates that the associated objects before and after are an "or" relationship. It should also be understood that the description of each embodiment in the present disclosure emphasizes the differences between the embodiments, and the same or similar parts can refer to each other. For the sake of brevity, they will not be repeated one by one.

[0021] At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. The techniques, methods and devices known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered part of the specification. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0023] Figure 1The present invention discloses a flow chart of a stirring motor control method for the production of immobilized enzymes disclosed in the embodiments of the present invention. It should be understood that the production of immobilized synthetic penicillin G acylase mainly includes three parts: fermentation, extraction, and immobilization. The specific process is as follows: during the fermentation process, seeds are connected to a seed tank, fermented to obtain seeds, and then transplanted to a fermentation tank for engineered bacteria fermentation. During the fermentation process, the enzyme activity is detected to determine the collection time; during the extraction process, the fermented bacterial liquid is collected through a ceramic membrane, and the collected bacterial bodies are then homogenized and crushed by a homogenizer. The crushed cell suspension is subjected to flocculation precipitation and plate-and-frame filtration to remove bacterial fragments, and the supernatant is purified by an ammonium sulfate precipitation process to remove impurities. The intermediate impurity removal also adopts a plate-and-frame method. The protein concentration and activity of the solution are determined to determine whether the purified supernatant meets the immobilization requirements. The supernatant that does not meet the requirements is subjected to an ammonium sulfate precipitation step and the ammonium sulfate purification process is repeated. The supernatant that meets the immobilization requirements is concentrated by ultrafiltration and used for subsequent immobilization; immobilization, after the above-mentioned extraction process meets the requirements, an appropriate amount of salt is added to the supernatant solution, and the treated immobilization carrier is added in a certain proportion, and the immobilization is slowly stirred in the immobilization tank. After the immobilization is completed, the supernatant is removed, and then the washing post-treatment process is carried out. The immobilized enzyme is filtered and packaged to obtain the immobilized enzyme product.

[0024] In order to enable the motor to perform efficient stirring in the entire process of immobilized enzyme production, the present application embodiment discloses a stirring motor control method for immobilized enzyme production, such as Figure 1 As shown, at step S101, during the bacterial inoculation and stirring stage, the stirring motor is controlled to start to the first preset speed by calculating the control amount of the speed deviation and inputting it into the frequency converter, and the speed is adjusted by using the vector control of the permanent magnet synchronous motor. This includes: controlling the stirring motor to start to the preset speed, controlling the starting current to be less than a predetermined multiple of the rated current; using the speed deviation to calculate the control amount, wherein the control amount is composed of a steady-state term and a dynamic term, and the steady-state term is calculated according to the ratio of the target speed to the rated speed; the dynamic term is calculated according to the speed deviation and its integral, and the synthetic control amount is input into the frequency converter to drive the motor; the speed adjustment is realized by the vector control of the permanent magnet synchronous motor, so that the speed fluctuation is controlled within a predetermined range.

[0025] Specifically, during the stirring process of the immobilized enzyme fermentation tank, the speed control of the stirring motor is divided into four stages. The first stage is the bacterial inoculation stirring stage. In one embodiment, the speed of the stirring motor is set at 227rpm in this stage, and the starting current of the motor is controlled to be less than 2.3 times the rated current by the frequency converter, so that the speed rises to the set value within 16.5 seconds. In the bacterial inoculation stage, the motor control adopts the following scheme: when the stirring motor starts, the controller calculates the control amount according to the speed deviation. Let the actual speed be ω, the target speed be ω*, and the speed deviation e = ω* - ω. The control law consists of two parts: the steady-state term us and the dynamic term ud. The steady-state term ensures that the system reaches the target speed: us = (ω* / ωn)·un, where ωn is the rated speed of the motor and un is the rated control voltage. The dynamic term ensures that the speed regulation process is smooth: ud = -k1·e - k2∫e·dt, where k1=2.37 and k2=0.83 are controller parameters. The synthetic control quantity u = us + ud is sent to the inverter, and the inverter outputs a three-phase voltage to drive the motor. The torque of the stirring motor is maintained at 58.3% of the rated torque, and the speed is adjusted through the vector control of the permanent magnet synchronous motor, and the speed fluctuation is controlled within ±1.2rpm.

[0026] At step S102, during the fermentation, proliferation and stirring stage, the stirring motor speed is increased to a second preset speed, a torque pre-compensation scheme is used to establish a torque estimation model, and the viscosity coefficient is calculated and the output is adjusted according to the fermentation time. This includes: increasing the stirring motor speed to the second preset speed, wherein the slope of the speed increase process is a predetermined value; adopting the torque pre-compensation scheme, establishing a torque estimation model according to the law of change of the viscosity of the fermentation liquid; calculating the equivalent viscosity coefficient of the fermentation liquid according to the fermentation time, estimating the torque and adjusting the output in advance; when the radial vibration amplitude of the stirring shaft exceeds the predetermined value, reducing the speed to a predetermined value.

[0027] Among them, the torque estimation model is established according to the change law of fermentation liquid viscosity, including: ,in, represents torque, represents the equivalent viscosity coefficient of the fermentation broth, Indicates the speed, represents the moment of inertia, represents the angular acceleration, Represents the damping coefficient.

[0028] The second stage is the fermentation and proliferation stirring stage. In one embodiment, the stirring motor speed is increased to 382 rpm, and the slope of the speed increase process is 4.7 rpm / s. The control of the fermentation and proliferation stage adopts a torque pre-compensation scheme. According to the law of change of the viscosity of the fermentation liquid, a torque estimation model is established: , where μ(t) is the equivalent viscosity coefficient of the fermentation liquid, which changes exponentially with the fermentation time: μ(t) = μ0·exp(-αt) + μ∞, where μ0=1.83N·m·s / rad is the initial viscosity coefficient, α=0.0074s^-1 is the attenuation coefficient, and μ∞=0.67N·m·s / rad is the steady-state viscosity coefficient. J is the moment of inertia and D is the damping coefficient. The controller adjusts the output in advance according to the estimated torque to compensate for the disturbance caused by the viscosity change. The fundamental frequency of the motor supply voltage is synchronized with the speed, so that the magnetic flux density of the motor is maintained at 0.82Wb at 382rpm. When the radial vibration amplitude of the stirring shaft exceeds 0.187mm, the speed is reduced by 47rpm.

[0029] At step S103, in the homogenization crushing and stirring stage, the stirring motor speed is increased to the third preset speed, and the speed-torque dual-link control is adopted, and the corresponding control parameters are used to calculate the torque command for different speed sections. This includes: the stirring motor speed is increased to the third preset speed, and the speed-torque dual-link control scheme is adopted; the torque command is calculated according to the speed range by using the piecewise linearization method, and the low speed section and the high speed section respectively use corresponding control parameters; the inner loop adopts current tracking control to adjust the nonlinear characteristics of the control parameters; when the stator temperature exceeds the predetermined value, the speed is reduced to a predetermined value.

[0030] The third stage is the homogenization crushing and stirring stage. In one embodiment, the stirring motor speed is increased to 687rpm. The homogenization crushing stage adopts speed-torque dual-link control. The outer loop controller adopts a piecewise linearization method: the speed range is divided into a low-speed section (<382rpm) and a high-speed section (≥382rpm), and different control parameters are used respectively. Below 382rpm, the torque command Tc is calculated as follows: Tc = Kr·(1 + 0.0023·ω)·e + Ki·∫e·dt, where Kr=1.86 and Ki=0.52 are controller parameters. Above 382rpm: Tc = Kr·(1 + 0.0047·ω)·e + Ki·∫e·dt, where Kr=2.13 and Ki=0.78. The inner loop adopts current tracking control, and the current command is proportional to the torque command. By adjusting the nonlinear characteristics of the control parameters, the changes in motor parameters at high speed are compensated. When the stator temperature exceeds 83.5℃, the speed is reduced by 96rpm and the motor power factor is compensated to 0.967.

[0031] At step S104, during the immobilization reaction stirring stage, the stirring motor speed is reduced to a fourth preset speed, rotor flux oriented control is adopted, and the q-axis current command is processed by low-pass filtering until the speed drops to zero. This includes: reducing the stirring motor speed to a fourth preset speed, adopting rotor flux oriented control; controlling the rotor flux vector to coincide with the d-axis, keeping the rotor flux modulus and the d-axis current at a predetermined value; performing low-pass filtering on the q-axis current command, and dynamically adjusting it according to the torque demand; controlling the three-phase winding current imbalance within a predetermined range, and finally reducing the speed to zero within a predetermined time.

[0032] Among them, the q-axis current command is low-pass filtered and dynamically adjusted according to the torque demand, including: ,in, Indicates the q-axis current command, represents the first filter time constant, represents the second filter time constant, represents the target torque, Represents the torque coefficient.

[0033] The fourth stage is the immobilization reaction stirring stage. In one embodiment, the stirring motor speed is reduced to 183rpm. The immobilization reaction stage focuses on controlling torque fluctuations and adopts rotor flux directional control. Directional control ensures that the rotor flux vector coincides with the d-axis and the rotor flux modulus is maintained at 0.93Wb. The d-axis current is controlled at 2.83A, and the q-axis current is dynamically adjusted according to the torque demand. To suppress torque fluctuations, the q-axis current command is processed by a low-pass filter: ,in =0.023s, =0.187s is the filtering time constant, kt is the torque coefficient. The unbalance degree of the three-phase winding current is controlled within 4.7%. At the end of the stirring process, the speed gradually decreases to 0 within 28.5 seconds.

[0034] The system uses a speed and torque double closed loop. The integral parameter of the speed outer loop is adaptively adjusted according to the speed error, and the control period of the torque inner loop is 0.187ms. When the torque exceeds the limit value, the system adjusts the speed until the torque returns to 92.3% of the rated value.

[0035] Figure 2A schematic block diagram of a stirring motor control system disclosed in an embodiment of the present application. It should be understood that the system shown in the figure is exemplary and not restrictive. This means that the system architecture involved is not limited to a specific form or design, but is presented as an example. In other words, the architecture shown in the figure can be regarded as a way of expression to clearly describe related concepts and relationships, and does not exclude other forms of architecture. Therefore, when interpreting the architecture in the picture, it should be understood that the model is flexible and diverse, and its purpose is to disclose an exemplary description rather than a restrictive provision on a specific form.

[0036] The present application discloses a control system that applies the stirring motor control method described in the above embodiment, including: a power supply unit, including a three-phase AC input terminal; a power conversion unit, including an active rectifier and an inverter connected through a DC bus, and the active rectifier is electrically connected to the power supply unit; a motor drive unit, including a permanent magnet synchronous motor, whose stator winding is electrically connected to the output terminal of the inverter, and a permanent magnet is mounted on the rotor surface; a feedback unit, including a position sensor, a current sensor and a temperature sensor, for collecting operating status parameters of the permanent magnet synchronous motor; and a control unit, including a dual DSP structure, configured with a space vector PWM modulation algorithm, a rotor flux orientation algorithm and a speed and torque dual closed-loop control algorithm, for controlling the operation of the permanent magnet synchronous motor according to the parameters collected by the feedback unit.

[0037] Preferably, the power supply unit includes three-phase AC power supplies R, S, and T, and the output ends thereof are electrically connected to the input ends of the power conversion unit, respectively. The power conversion unit includes an active rectifier and an IGBT inverter, which are connected via a DC bus. The input end of the active rectifier is connected to the three-phase AC power supply, and the output end is connected to the positive and negative poles of the DC bus; the DC side of the IGBT inverter is connected to the DC bus, and the AC side is connected to the three-phase windings U, V, and W of the permanent magnet synchronous motor. The operating voltage of the DC bus is 537V, and the ripple factor is controlled below 2.3%.

[0038] The motor drive unit adopts a permanent magnet synchronous motor with a Y-shaped stator winding connection, a rated power of 2.83kW, a rated speed of 1437rpm, a NdFeB permanent magnet mounted on the rotor surface, and a magnetic flux density of 0.93Wb. A Hall position sensor is set at the motor shaft end, and a PT100 temperature sensor is built into the stator winding, which are used for rotor position detection and motor temperature monitoring respectively.

[0039] The feedback unit includes: a Hall position sensor, whose output signal is sent to the control unit after passing through a signal conditioning circuit to realize rotor magnetic field orientation; a phase current sampling circuit, which adopts a closed-loop Hall current sensor with a sampling resistor of 183Ω, and the sampling signal is sent to the control system after 14-bit AD conversion; a temperature acquisition circuit with a sampling period of 1.87ms and a measurement range of -17.3℃ to 126.7℃.

[0040] The control unit adopts a dual DSP structure: the master DSP is responsible for speed loop and torque loop control, and the slave DSP is responsible for current loop control and PWM signal generation. The master and slave DSPs realize data exchange through the SPI interface, and the communication rate is 8.37Mbps. The core algorithms of the control unit include: space vector PWM modulation, switching frequency 8.73kHz, dead time 2.83μs; rotor flux orientation algorithm, position solution cycle 0.187ms; speed and torque dual closed-loop control, speed loop sampling cycle 1.87ms, torque loop sampling cycle 0.187ms.

[0041] The signal connection between each unit uses a twisted-pair shielded cable with a grounding resistance of ≤0.47Ω. The power device uses an IGBT module with a rated current of 137A and a blocking voltage of 1137V, and is equipped with overcurrent protection, overvoltage protection and short-circuit protection circuits. The overall structure of the system ensures that the motor speed and torque can smoothly transition according to the preset trajectory in the four working stages.

[0042] Furthermore, an embodiment of the present application also discloses a stirring motor control device for immobilized enzyme production, comprising: a processor, a memory, and a system bus; the processor and the memory are connected via the system bus; the memory is used to store one or more programs, and the one or more programs include instructions, which, when executed by the processor, enable the processor to execute any of the above methods.

[0043] Furthermore, an embodiment of the present application also discloses a computer program product, which, when executed on a terminal device, enables the terminal device to execute any of the above methods.

[0044] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0045] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0046] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0047] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A stirring motor control method for immobilized enzyme production, characterized in that: include: During the bacterial inoculation and stirring stage, the stirring motor is controlled to start at the first preset speed by calculating the control amount of the speed deviation and inputting it into the frequency converter, and the speed is adjusted by using the vector control of the permanent magnet synchronous motor; During the fermentation, proliferation and stirring stage, the stirring motor speed is increased to the second preset speed, and a torque pre-compensation scheme is used to establish a torque estimation model, and the viscosity coefficient is calculated and the output is adjusted according to the fermentation time; In the homogenization crushing and stirring stage, the stirring motor speed is increased to the third preset speed, and the speed-torque dual-link control is adopted, and the torque command is calculated using the corresponding control parameters for different speed sections; In the immobilization reaction stirring stage, the stirring motor speed is reduced to a fourth preset speed, and the rotor flux oriented control is adopted to process the q-axis current command through low-pass filtering until the speed drops to zero; Increase the stirring motor speed to the second preset speed, use the torque pre-compensation scheme to establish a torque estimation model, calculate the viscosity coefficient according to the fermentation time and adjust the output, including: The stirring motor speed is increased to a second preset speed, wherein the slope of the speed increase process is a predetermined value; The torque pre-compensation scheme is adopted, and the torque estimation model is established according to the variation law of fermentation liquid viscosity; Calculate the equivalent viscosity coefficient of the fermentation liquid according to the fermentation time, estimate the torque and adjust the output in advance; When the radial vibration amplitude of the stirring shaft exceeds a predetermined value, the rotation speed is reduced to a predetermined value; The torque estimation model is established according to the change law of fermentation liquid viscosity, including: ， in, represents torque, represents the equivalent viscosity coefficient of the fermentation broth, Indicates the speed, represents the moment of inertia, represents the angular acceleration, Represents the damping coefficient.

2. The stirring motor control method according to claim 1, characterized in that: in, By calculating the control amount of the speed deviation and inputting it into the frequency converter, the stirring motor is controlled to start to the first preset speed, and the speed is adjusted by using the vector control of the permanent magnet synchronous motor, including: Control the stirring motor to start at a preset speed and control the starting current to be below a predetermined multiple of the rated current; The speed deviation is used to calculate the control quantity, where the control quantity consists of a steady-state term and a dynamic term. The steady-state term is calculated according to the ratio of the target speed to the rated speed. The dynamic term is calculated based on the speed deviation and its integral, and the resultant control quantity is input into the inverter to drive the motor; The speed is adjusted by vector control of the permanent magnet synchronous motor, so that the speed fluctuation is controlled within a predetermined range.

3. The stirring motor control method according to claim 1, characterized in that: in, In the homogenization crushing and stirring stage, the stirring motor speed is increased to the third preset speed, and the speed-torque dual-link control is adopted. The torque command is calculated using corresponding control parameters for different speed sections, including: The stirring motor speed is increased to the third preset speed, and a speed-torque dual-link control scheme is adopted; The torque command is calculated using the piecewise linearization method according to the speed range, and the corresponding control parameters are used in the low-speed section and the high-speed section respectively; The inner loop adopts current tracking control to adjust the nonlinear characteristics of the control parameters; When the stator temperature exceeds a preset value, the speed is reduced to a preset value.

4. The stirring motor control method according to claim 1, characterized in that: in, In the immobilized reaction stirring stage, the stirring motor speed is reduced to the fourth preset speed, and the rotor flux oriented control is adopted to process the q-axis current command through low-pass filtering until the speed drops to zero, including: The stirring motor speed is reduced to the fourth preset speed, and rotor flux directional control is adopted; Control the rotor flux vector to coincide with the d-axis, and keep the rotor flux modulus and d-axis current at a predetermined value; The q-axis current command is low-pass filtered and dynamically adjusted according to the torque demand; The unbalance degree of the three-phase winding current is controlled within a predetermined range, and finally the speed is reduced to zero within a predetermined time.

5. The stirring motor control method according to claim 4, characterized in that: in, The q-axis current command is low-pass filtered and dynamically adjusted according to the torque demand, including: ， in, Indicates the q-axis current command, represents the first filter time constant, represents the second filter time constant, represents the target torque, Represents the torque coefficient.

6. A control system using the stirring motor control method according to any one of claims 1 to 5, characterized in that: include: A power supply unit, comprising a three-phase AC input terminal; A power conversion unit, comprising an active rectifier and an inverter connected via a DC bus, wherein the active rectifier is electrically connected to the power supply unit; The motor drive unit comprises a permanent magnet synchronous motor, the stator winding of which is electrically connected to the output terminal of the inverter, and the permanent magnet is mounted on the surface of the rotor; A feedback unit, including a position sensor, a current sensor and a temperature sensor, for collecting operating state parameters of the permanent magnet synchronous motor; as well as The control unit includes a dual DSP structure, and is equipped with a space vector PWM modulation algorithm, a rotor flux orientation algorithm, and a speed-torque dual closed-loop control algorithm, and is used to control the operation of the permanent magnet synchronous motor according to the parameters collected by the feedback unit.

7. A stirring motor control device for the production of immobilized enzymes, characterized in that: include: A processor, a memory, and a system bus; wherein the processor and the memory are connected via the system bus; The memory is used to store one or more programs, wherein the one or more programs include instructions, and when the instructions are executed by the processor, the processor executes the method according to any one of claims 1 to 5.

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