Control method for motor start-stop impact section flexible suppression

Abstract

The application discloses a control method for motor start-stop impact section flexible suppression, comprising the following steps: based on the current working condition stage, calling the corresponding working condition preset nonlinear regulation rule, correcting the proportional coefficient Kp, integral coefficient Ki and differential coefficient Kd of the nonlinear PID controller to adapt to the motor dynamic characteristics in different start-stop stages; the nonlinear regulation rule is determined based on the nonlinear regulation coefficient, the speed error determined by the motor target speed and the actual speed, and the reference coefficient; on the basis of correcting the Kp, Ki and Kd parameters of the nonlinear PID controller, the motor stator current and electromagnetic torque operation data are collected in real time, and the control parameters are corrected based on the collected data; the nonlinear PID controller continuously outputs the regulation voltage or regulation current based on the real-time corrected control parameters, and completes the motor start-stop whole process impact suppression. The flexible and accurate control of the motor start-stop impact is realized, the control precision is improved, and the CT performance is improved.

Description

Technical Field

[0001] This invention relates to the field of information processing technology, specifically to a control method for segmented flexible suppression of motor start-stop impact. Background Technology

[0002] To address the issue of motor start-stop shock, existing technologies have proposed various control schemes, mainly falling into two categories: one is hardware-level improvements, such as using soft starters and frequency converters to achieve smooth motor start-stop through voltage and frequency regulation. However, these schemes suffer from high costs, complex hardware structures, and increased energy consumption, and are less suitable for some small devices or low-cost scenarios. The other category is optimization at the control strategy level. Among these, PID control is widely used in motor control due to its simple structure and ease of implementation. However, the fixed parameters of traditional linear PID controllers make it difficult to adapt to the nonlinear and time-varying dynamic characteristics of motor start-stop processes. In the initial stage of start-stop, the system error is large, requiring strong control action to suppress the shock, but the fixed parameters of traditional PID cannot respond quickly. In the later stage of start-stop, the system tends to stabilize, requiring weaker control action to avoid overshoot. Traditional PID is prone to overshoot and oscillation, resulting in poor shock suppression.

[0003] While existing nonlinear PID control strategies attempt to adapt to nonlinear changes in the system by adjusting control parameters, most employ a single, global nonlinear regulation rule. They fail to consider the dynamic characteristics of different stages of motor start-up and shutdown (initial start-up, mid-start-up, late start-up, initial shutdown, mid-shutdown, and late shutdown) for segmented control. This results in insufficient smoothness during start-up and shutdown, incomplete impact suppression, and poor system robustness. Furthermore, some segmented control strategies do not adequately consider the coupling relationship between current, torque, and speed during motor start-up and shutdown, leading to low control accuracy and making it difficult to meet the requirements for high-precision, low-impact start-up and shutdown control. Summary of the Invention

[0004] The main objective of this invention is to provide a control method for segmented flexible suppression of motor start-stop impact, in order to overcome the shortcomings of related technologies.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a control method for segmented flexible suppression of motor start-stop impact is provided. The method is applied to CT motor drive equipment with or without a similar grating ruler structure. The method includes, based on the current operating condition stage, invoking a preset nonlinear adjustment rule for the corresponding operating condition to correct the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd of the nonlinear PID controller to adapt to the dynamic characteristics of the motor in different start-stop stages. Specifically, the motor's rated speed is used as a criterion, and current and torque change thresholds are combined to divide the motor's operating state into different operating condition stages. The nonlinear adjustment rule is determined based on the nonlinear adjustment coefficient, the speed error determined by the motor's target speed and actual speed, and the reference coefficient. Based on the corrected Kp, Ki, and Kd parameters of the nonlinear PID controller, real-time acquisition of motor stator current and electromagnetic torque operating data is conducted, and the control parameters are corrected based on the acquired data. The nonlinear PID controller continuously outputs a regulating voltage or regulating current based on the real-time corrected control parameters to complete the impact suppression throughout the entire motor start-stop process.

[0006] Optionally, the output u(t) of the nonlinear PID controller satisfies the following formula: Where e is the speed error and ec is the rate of change of the speed error. It is a non-linear proportionality coefficient. For nonlinear integral coefficients, These are nonlinear differential coefficients, which change dynamically with the input signals e and ec, and different nonlinear adjustment rules are used in different start-stop phases.

[0007] Optionally, the motor operating state can be divided into different operating condition stages, including: if the motor speed n∈[0,0.2n], the motor transitions from standstill to motion, which is classified as the initial startup stage; if the motor speed n∈(0.2n,0.8n], the motor speed rises rapidly, which is classified as the middle startup stage; if the motor speed n∈(0.8n,n], the motor speed approaches the rated speed, which is classified as the late startup stage; if the motor speed n∈(0.8n,n], the motor begins to decelerate and the torque reverses, which is classified as the initial shutdown stage; if the motor speed n∈(0.2n,0.8n], the motor speed drops rapidly, which is classified as the middle shutdown stage; if the motor speed n∈[0,0.2n], the motor speed approaches standstill, which is classified as the late shutdown stage; wherein, the speed threshold for each operating condition stage is adaptively adjusted by ±k% according to the motor type and load characteristics.

[0008] Based on the current operating condition stage, the corresponding preset nonlinear adjustment rules are invoked to correct the Kp, Ki, and Kd parameters of the nonlinear PID controller, including: for the initial startup phase, the proportional coefficient Kp adopts an exponential nonlinear function, which decreases as the error e decreases, as shown in the formula: Where Kp0 is the initial reference proportional coefficient, and a is the nonlinear adjustment coefficient, ensuring that Kp is large when the error is large to quickly respond to the error, and decreases Kp when the error decreases to avoid excessive impact; the integral coefficient Ki adopts a saturated nonlinear function to limit the integral action and avoid overshoot caused by integral saturation, the formula is as follows. Where Ki0 is the initial baseline integral coefficient to ensure a gentle integral action, only taking effect when the error is small; the differential coefficient Kd adopts a linearly increasing function, increasing with the rate of change of error ec, as shown in the formula: Where Kd0 is the initial reference differential coefficient and b is the differential adjustment coefficient, which enhances the differential effect and suppresses sudden shocks in torque and current.

[0009] Optionally, for the mid-start-up phase, the proportional coefficient Kp adopts a linearly decreasing function, decreasing linearly with the increase of the engine speed n, as shown in the formula: Where Kp1 is the starting mid-term reference proportional coefficient; the integral coefficient Ki adopts a linearly increasing function, increasing linearly with the increase of speed n, as shown in the formula: Ki1 is the baseline integral coefficient during the startup phase (typically 0.8-1.0 times the traditional PID integral coefficient), gradually enhancing the integral action and eliminating steady-state error; the derivative coefficient Kd is a constant function, maintaining a fixed value. Kd1 is the mid-term reference differential coefficient during startup, which maintains the stability of the differential action and suppresses speed oscillation.

[0010] Optionally, for the later stages of startup, the proportional coefficient Kp adopts an exponentially decreasing function, decreasing rapidly as the speed n approaches the rated value, as shown in the formula: Where c is the proportional adjustment coefficient, ensuring that Kp is kept at a small level to avoid overshoot; the integral coefficient Ki adopts an exponentially increasing function, increasing rapidly as the speed n approaches the rated value, as shown in the formula: Where d is the integral adjustment coefficient, enhancing the integral effect; the derivative coefficient Kd adopts a linearly decreasing function, decreasing linearly as the speed n approaches the rated value, as shown in the formula: Kd2 is the baseline differential coefficient in the later stage of startup, which weakens the differential effect and avoids steady-state oscillation.

[0011] Optionally, for the initial stage of shutdown, the proportional coefficient Kp adopts an absolute value exponential function, increasing with the increase of the absolute value of the error |e|, as shown in the formula: Where Kp2 is the initial reference proportional coefficient during shutdown, a is the nonlinear adjustment coefficient, which quickly responds to deceleration errors and suppresses torque reverse impact; the integral coefficient Ki adopts a saturated nonlinear function to limit the integral action, and the formula is as follows: Where Ki2 is the baseline integral coefficient at the initial stage of shutdown to avoid shutdown shock caused by integral saturation; the differential coefficient Kd adopts a linearly increasing function, which increases with the absolute value of the error rate of change ec, as shown in the formula. Where Kd2 is the baseline differential coefficient at the initial shutdown stage, and b is the differential adjustment coefficient (consistent with the initial startup stage) to suppress the impact caused by the rapid drop in speed.

[0012] Optionally, for the mid-term shutdown, the shutdown proportional coefficient Kp adopts a linearly increasing function, increasing linearly as the speed n decreases, as shown in the formula: Where Kp3 is the mid-term reference proportional coefficient during shutdown, ensuring a smooth transition of Kp and avoiding current surges; the integral coefficient Ki adopts a linearly increasing function, increasing linearly with the decrease of speed n, as shown in the formula: Ki3 is the baseline integral coefficient during the mid-stop process, gradually increasing the integral action to smoothly decelerate the engine; the differential coefficient Kd is a constant function, maintaining a fixed value. Kd3 is the baseline differential coefficient during the shutdown period, which maintains the stability of the differential action and suppresses speed oscillation.

[0013] Optionally, for the later stage of shutdown, the proportional coefficient Kp adopts an exponentially decreasing function, decreasing rapidly as the rotational speed n decreases, as shown in the formula: Where c is the proportional control coefficient, ensuring Kp remains at a low level to prevent sudden motor stoppage; the integral coefficient Ki uses an exponentially increasing function, increasing rapidly as the speed n decreases, as shown in the formula: Where d is the integral adjustment coefficient, which enhances the integral action and ensures that the speed smoothly drops to 0; the derivative coefficient Kd adopts a linearly decreasing function, which decreases linearly with the decrease of speed n, and the formula is: Kd4 is the baseline differential coefficient in the later stage of shutdown, which reduces the differential effect and avoids mechanical shock.

[0014] Optionally, the control parameters are corrected based on the collected data, including: when the motor stator current exceeds the rated current K1 times, Kp and Ki are lowered and Kd is increased for the current stage; when the current is lower than the rated current k2 times, Kp and Ki are increased to accelerate the speed response; when the rate of change of the motor electromagnetic torque exceeds the threshold of m times / ms of the rated torque, the nonlinear adjustment coefficient is adjusted, where the nonlinear condition coefficient is the nonlinear curvature adjustment coefficient, used to change the nonlinear change rate and curve shape of the PID parameters in each stage, and in conjunction with the sensitivity of the feedback dynamic correction parameters of the electromagnetic torque, so that Kp, Ki, and Kd conform to the nonlinear change law of different start-stop stages of the motor, thereby improving the impact suppression compliance; after a single start-stop cycle is completed, the reference parameters of each stage are optimized based on the impact peak value, overshoot, and steady-state error to achieve adaptive iterative optimization. This embodiment of the control method for segmented flexible suppression of motor start-stop impact includes, based on the current operating condition stage, invoking a preset nonlinear adjustment rule for the corresponding operating condition to correct the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd of the nonlinear PID controller to adapt to the dynamic characteristics of the motor in different start-stop stages. Specifically, the motor's rated speed is used as a criterion, and current and torque change thresholds are combined to divide the motor operating state into different operating condition stages. The nonlinear adjustment rule is determined based on the nonlinear adjustment coefficient, the speed error between the target speed and the actual speed of the motor, and the reference coefficient. Based on the corrected Kp, Ki, and Kd parameters of the nonlinear PID controller, real-time data on the motor stator current and electromagnetic torque are collected, and the control parameters are corrected based on the collected data. The nonlinear PID controller continuously outputs regulating voltage or regulating current based on the real-time corrected control parameters to complete the impact suppression throughout the entire motor start-stop process. By segmenting the motor start-stop stages and designing nonlinear PID control rules adapted to the dynamic characteristics of each stage, flexible and precise control of motor start-stop impact is achieved, improving control accuracy and enhancing CT performance. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the control method for segmented flexible suppression of motor start-stop impact according to an embodiment of the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] According to embodiments of the present invention, a control method for segmented flexible suppression of motor start-stop impact is provided, such as... Figure 1 As shown, steps 101 to 103 are included below: Step 101: Based on the current operating condition stage, call the corresponding preset nonlinear adjustment rule to correct the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd of the nonlinear PID controller to adapt to the dynamic characteristics of the motor in different start-stop stages. Here, the rated speed of the motor is used as the judgment benchmark, and the current and torque change thresholds are combined to divide the motor operating state into different operating condition stages. The nonlinear adjustment rule is determined based on the nonlinear adjustment coefficient, the speed error between the target speed and the actual speed of the motor, and the benchmark proportional coefficient.

[0021] In this step, based on the motor's rated speed nN and considering the threshold values ​​for changes in current and torque, the motor start-up and shutdown process is divided into six stages. The criteria for each stage are as follows: 1. Initial startup: Motor speed n ∈ [0, 0.2nN]. At this time, the motor is in a state of transition from stationary to moving. The current and torque change significantly and the impact is the greatest. The core requirement is to quickly suppress the initial impact and avoid current and torque overload. 2. Mid-startup: Motor speed n ∈ (0.2nN, 0.8nN], at this time the motor speed rises rapidly, and the current and torque gradually stabilize. The core requirement is to balance the speed increase rate and shock suppression to avoid speed overshoot; 3. Late start-up: Motor speed n ∈ (0.8nN, nN], at which time the motor speed is close to the rated speed and the system tends to stabilize. The core requirement is to fine-tune the control parameters to achieve a smooth transition of the speed to the rated value and avoid steady-state oscillation. 4. Initial shutdown phase: Motor speed n ∈ (0.8nN, nN], at which point the motor begins to decelerate and the torque reverses. The core requirement is to suppress the torque surge during the initial deceleration phase to avoid damage to the mechanical transmission mechanism. 5. Mid-term shutdown: Motor speed n ∈ (0.2nN, 0.8nN], at this time the motor speed drops rapidly and the current changes in the opposite direction. The core requirement is to decelerate smoothly and avoid current surges and speed oscillations. 6. Later stage of shutdown: The motor speed n ∈ [0, 0.2nN]. At this time, the motor speed is close to a standstill. The core requirement is a smooth shutdown to avoid the mechanical shock caused by the sudden stop of the motor and ensure that the speed drops smoothly to 0.

[0022] It should be understood that the speed thresholds for each stage can be adaptively adjusted according to the motor type (asynchronous motor, synchronous motor) and load characteristics, with an adjustment range of ±10%, to adapt to the control requirements of different scenarios.

[0023] In the nonlinear adjustment rule, the nonlinear adjustment coefficients are embedded within the nonlinear calculation formula to control the rate, magnitude, and curvature of Kp, Ki, and Kd changes with error and speed, determining the steepness of the nonlinear change curve of the PID parameters and indirectly altering the generated results of real-time Kp, Ki, and Kd. The reference coefficients include the reference proportional coefficient Kp, the reference integral coefficient, and the reference derivative coefficient Kd. After each start-stop cycle, based on indicators such as the peak impact, overshoot, and steady-state error during the start-stop process, the reference parameters for each stage are automatically optimized to achieve adaptive optimization of the control strategy and improve the impact suppression effect under different operating conditions.

[0024] By dividing the motor start-stop phase into segments and configuring nonlinear PID control rules adapted to the dynamic characteristics of each phase, flexible and precise control of the motor start-stop impact can be achieved, thereby improving control accuracy and enhancing CT performance.

[0025] As an optional implementation in this embodiment, the output u(t) of the nonlinear PID controller satisfies the following formula: Where e represents the speed error and ec represents the rate of change of the speed error. It is a non-linear proportionality coefficient. For nonlinear integral coefficients, These are nonlinear differential coefficients, which change dynamically with the input signals e and ec, and different nonlinear adjustment rules are used in different start-stop phases.

[0026] In this optional implementation, the nonlinear PID controller takes the speed error e (e = target speed - actual speed) and the speed error change rate ec (ec = de / dt) as inputs, and outputs the motor control voltage or current. It dynamically adjusts the three parameters Kp, Ki, and Kd through nonlinear functions to achieve segmented flexible control.

[0027] The output u(t) of the PID controller satisfies the following formula Where Kp(e(t)) is a nonlinear proportional coefficient, Ki(e(t), ec(t)) is a nonlinear integral coefficient, and Kd(ec(t)) is a nonlinear derivative coefficient, all of which change dynamically with the input signal (e, ec) and adopt different nonlinear adjustment rules in different start-stop phases.

[0028] As an optional implementation in this embodiment, during the initial startup phase (n ∈ [0, 0.2nN]), the speed error e is relatively large, and the current and torque change abruptly. Therefore, a control strategy of "strong proportional, weak integral, strong derivative" is required to quickly suppress the initial impact and avoid overload. 1. Proportional coefficient Kp: Employs an exponential nonlinear function, decreasing as the error e decreases. The formula is as follows: Kp0 is the initial reference proportional coefficient during startup (set according to the rated parameters of the motor, usually 1.2-1.5 times the proportional coefficient of the traditional PID), and a is the nonlinear adjustment coefficient (a>0, with a value range of 0.5-1.0). This ensures that Kp is larger when the error is large, so as to respond quickly to the error. When the error decreases, Kp decreases to avoid excessive impact. 2. Integral coefficient Ki: A saturated nonlinear function is used to limit the integral action and avoid overshoot caused by integral saturation. The formula is as follows: Ki0 is the baseline integral coefficient at the initial startup stage (usually 0.3-0.5 times the integral coefficient of a traditional PID controller), ensuring that the integral action is gentle and only takes effect when the error is small. 3. Differential coefficient Kd: Adopts a linearly increasing function, increasing with the rate of change of error ec, as shown in the formula: Kd0 is the initial base differential coefficient (usually 1.3-1.6 times the traditional PID differential coefficient), and b is the differential adjustment coefficient (b>0, with a value range of 0.3-0.6), which enhances the differential effect and suppresses sudden shocks in torque and current.

[0029] As an optional implementation in this embodiment, during the mid-startup phase (n ∈ (0.2nN, 0.8nN]), the speed increases rapidly, the error e gradually decreases, and the current and torque tend to stabilize. A "medium proportional, medium integral, medium derivative" control strategy is required to balance speed increase and impact suppression. 1. Proportional coefficient Kp: It adopts a linearly decreasing function, decreasing linearly with the increase of rotational speed n, and the formula is as follows: Kp1 is the mid-start reference proportional coefficient (usually 0.8-1.0 times the traditional PID proportional coefficient) to ensure a smooth transition of Kp and avoid speed overshoot. 2. Integral coefficient Ki: Employs a linearly increasing function, increasing linearly with the rotational speed n, as shown in the formula... Ki1 is the baseline integral coefficient during the startup phase (usually 0.8-1.0 times the integral coefficient of a traditional PID controller), which gradually enhances the integral action and eliminates steady-state error. 3. Differential coefficient Kd: Use a constant function to maintain a fixed value. Kd1 is the mid-start reference differential coefficient (usually 0.9-1.1 times the traditional PID differential coefficient), which maintains the stability of the differential action and suppresses speed oscillation.

[0030] As an optional implementation method in this embodiment, in the later stage of startup (n ∈ (0.8nN, nN]), the speed is close to the rated value, the system tends to be stable, and the error e is small. Therefore, a control strategy of "weak proportional, strong integral, and weak derivative" should be adopted to achieve a smooth transition. 1. Proportional coefficient Kp: It adopts an exponentially decreasing function, which decreases rapidly as the rotational speed n approaches the rated value. The formula is as follows: Where c is the proportional adjustment coefficient (c>0, with a value range of 1.0-1.5), ensuring that Kp is kept at a small level to avoid overshoot; 2. Integral coefficient Ki: Employs an exponentially increasing function, rapidly increasing as the rotational speed n approaches its rated value. The formula is as follows: , where d is the integral adjustment coefficient (d>0, with a value range of 0.8-1.2), which enhances the integral effect and completely eliminates steady-state error; 3. Differential coefficient Kd: Employs a linearly decreasing function, decreasing linearly as the rotational speed n approaches its rated value. The formula is as follows: Kd2 is the baseline differential coefficient in the later stage of startup (usually 0.5-0.7 times the traditional PID differential coefficient), which weakens the differential effect and avoids steady-state oscillation.

[0031] As an optional implementation in this embodiment, during the initial shutdown phase (n ∈ (0.8nN, nN]), the motor begins to decelerate, the torque reverses, and the error e is negative (the target speed is lower than the actual speed). Therefore, a control strategy of "strong proportional, weak integral, strong derivative" is required to suppress deceleration shock. 1. Proportional coefficient Kp: It adopts an absolute value exponential function, which increases with the increase of the absolute value of the error |e|, and the formula is as follows: Kp2 is the initial reference proportional coefficient during shutdown (usually 1.2-1.4 times the proportional coefficient of a traditional PID), and a is the nonlinear adjustment coefficient (consistent with the initial startup), which quickly responds to deceleration errors and suppresses torque reverse impact. 2. Integral coefficient Ki: A saturated nonlinear function is used to limit the integral action; the formula is as follows: Ki2 is the baseline integral coefficient at the initial stage of shutdown (usually 0.3-0.4 times the integral coefficient of traditional PID) to avoid shutdown shock caused by integral saturation; 3. Differential coefficient Kd: A linearly increasing function is used, which increases with the absolute value of the error rate of change ec, as shown in the formula: Kd2 is the baseline differential coefficient at the initial shutdown stage (usually 1.3-1.5 times the traditional PID differential coefficient), and b is the differential adjustment coefficient (consistent with the initial startup stage) to suppress the impact caused by the rapid drop in speed.

[0032] As an optional implementation in this embodiment, during the mid-stop phase (n ∈ (0.2nN, 0.8nN]), the speed decreases rapidly, the absolute value of the error e gradually increases, and the current changes in the opposite direction. Therefore, a "medium proportional, medium integral, medium derivative" control strategy is required for smooth deceleration. 1. Proportional coefficient Kp: It adopts a linearly increasing function, increasing linearly as the rotational speed n decreases. The formula is as follows: Kp3 is the mid-term reference proportional coefficient during shutdown (usually 0.9-1.1 times the traditional PID proportional coefficient) to ensure a smooth transition of Kp and avoid current surges. 2. Integral coefficient Ki: Employs a linearly increasing function, increasing linearly with decreasing rotational speed n, as shown in the formula... Ki3 is the baseline integral coefficient during the shutdown process (usually 0.8-1.0 times the integral coefficient of a traditional PID), which gradually enhances the integral action and smoothly decelerates the process. 3. Differential coefficient Kd: Use a constant function to maintain a fixed value. Kd3 is the baseline differential coefficient during the shutdown period (usually 0.9-1.1 times the traditional PID differential coefficient), which maintains the stability of the differential action and suppresses speed oscillation.

[0033] As an optional implementation in this embodiment, in the later stage of shutdown (n ∈ [0, 0.2nN]), the rotational speed is close to a standstill, and the absolute value of the error e is relatively large. Therefore, a control strategy of "weak proportional, strong integral, and weak derivative" is required to achieve a flexible shutdown. 1. Proportional coefficient Kp: It adopts an exponentially decreasing function, decreasing rapidly as the rotational speed n decreases. The formula is as follows: Where c is the proportional adjustment coefficient (consistent with the later stage of startup), ensuring that Kp is kept at a small level to avoid sudden motor stoppage; 2. Integral coefficient Ki: It adopts an exponentially increasing function, which increases rapidly as the rotational speed n decreases. The formula is as follows: , where d is the integral adjustment coefficient (consistent with the later stage of startup), which enhances the integral effect and ensures that the speed drops smoothly to 0; 3. Differential coefficient Kd: Employs a linearly decreasing function, decreasing linearly with decreasing rotational speed n, as shown in the formula... Kd4 is the baseline differential coefficient in the later stage of shutdown (usually 0.4-0.6 times the traditional PID differential coefficient), which weakens the differential effect and avoids mechanical shock.

[0034] Step 102: Based on the correction of the Kp, Ki, and Kd parameters of the nonlinear PID controller, the stator current and electromagnetic torque operating data of the motor are collected in real time, and the control parameters are corrected based on the collected data; the nonlinear PID controller continuously outputs the regulating voltage or regulating current based on the real-time corrected control parameters to complete the impact suppression of the entire motor start-up and shutdown process.

[0035] In this step, to improve control accuracy and system robustness, current feedback and torque feedback are introduced to correct the PID control parameters in real time. 1. Current feedback: Real-time acquisition of motor stator current. When the current exceeds 1.2 times the rated current, Kp and Ki are automatically reduced and Kd is increased to suppress current surges. When the current is less than 0.8 times the rated current, Kp and Ki are appropriately increased to accelerate speed response. 2. Torque feedback: Real-time estimation of motor electromagnetic torque. When the torque change rate exceeds the set threshold (set according to the motor's rated torque, usually 0.1 times the rated torque / ms), the nonlinear adjustment coefficient (a, b, c, d) is automatically adjusted to enhance the impact suppression capability. 3. Parameter self-calibration: After each start-stop cycle is completed, the reference parameters (Kp0, Ki0, Kd0, etc.) of each stage are automatically optimized based on the peak impact, overshoot, steady-state error and other indicators during the start-stop process, so as to realize the adaptive optimization of the control strategy and improve the impact suppression effect under different operating conditions.

[0036] In this embodiment, based on operating condition control, Kp, Ki, and Kd can be initially generated, which belongs to the main regulation. Current feedback corrects Kp, Ki, and Kd, which belongs to the compensation regulation. Torque feedback modifies a, b, c, and d to optimize the curve shape.

[0037] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0038] According to an embodiment of the present invention, a control method and apparatus for segmented flexible suppression of motor start-stop impact is also provided, comprising a first adjustment unit, which, based on the current operating condition stage, invokes a preset nonlinear adjustment rule corresponding to the operating condition to correct the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd of the nonlinear PID controller to adapt to the dynamic characteristics of the motor in different start-stop stages. The motor's operating state is pre-divided into different operating condition stages based on the motor's rated speed as a criterion, combined with current and torque change thresholds. The nonlinear adjustment rule is determined based on the nonlinear adjustment coefficient, the speed error determined by the motor's target speed and actual speed, and the reference coefficient. A second adjustment unit, based on the corrected Kp, Ki, and Kd parameters of the nonlinear PID controller, collects real-time stator current and electromagnetic torque operating data of the motor, and corrects the control parameters based on the collected data. The nonlinear PID controller, based on the real-time corrected control parameters, continuously outputs a regulating voltage or regulating current to complete the impact suppression throughout the entire motor start-stop process.

[0039] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A control method for segmented flexible suppression of motor start-stop impact, characterized in that, The method is applied to CT motor drive equipment with grating rulers, and to CT motor drive equipment with similar grating ruler structures. The method includes: Based on the current operating condition stage, the corresponding preset nonlinear adjustment rules are invoked to correct the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd of the nonlinear PID controller, so as to adapt to the dynamic characteristics of the motor in different start-stop stages. Here, the rated speed of the motor is used as the judgment benchmark, and the motor operating state is divided into different operating condition stages in combination with the current and torque change thresholds. The nonlinear adjustment rules are determined based on the nonlinear adjustment coefficient, the speed error determined by the target speed and the actual speed of the motor, and the benchmark coefficient. Based on the correction of the Kp, Ki, and Kd parameters of the nonlinear PID controller, the stator current and electromagnetic torque operating data of the motor are collected in real time, and the control parameters are corrected based on the collected data. The nonlinear PID controller continuously outputs the regulating voltage or regulating current based on the real-time corrected control parameters to complete the impact suppression of the entire motor start-up and shutdown process.

2. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in claim 1, characterized in that, The output u(t) of the nonlinear PID controller satisfies the following formula: Where e represents the speed error and ec represents the rate of change of the speed error. It is a non-linear proportionality coefficient. For nonlinear integral coefficients, These are nonlinear differential coefficients, which change dynamically with the input signals e and ec, and different nonlinear adjustment rules are used in different start-stop phases.

3. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in claim 1, characterized in that, The motor's operating state is divided into different operating condition stages, including: If the motor speed n∈[0,0.2n], the transition of the motor from stationary to moving is classified as the initial startup phase; If the motor speed n∈(0.2n,0.8n], and the motor speed increases rapidly, then it is classified as the middle stage of startup; If the motor speed n∈(0.8n,n], and the motor speed approaches the rated speed, then it is classified as the late stage of startup; If the motor speed n∈(0.8n,n], the motor begins to decelerate and the torque reverses, then it is classified as the initial stage of shutdown. If the motor speed n∈(0.2n,0.8n], and the motor speed drops rapidly, it is classified as the middle stage of shutdown. If the motor speed n∈[0,0.2n], the motor speed approaches a standstill, and this is classified as the later stage of shutdown. The speed threshold for each operating condition stage is adaptively adjusted by ±k% based on the motor type and load characteristics.

4. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in claim 3, characterized in that, Based on the current operating condition, the corresponding preset nonlinear adjustment rules are invoked to correct the Kp, Ki, and Kd parameters of the nonlinear PID controller, including: For the initial startup phase, the proportional gain Kp adopts an exponential nonlinear function, decreasing as the error e decreases, as shown in the formula: Where Kp0 is the initial reference proportional coefficient and a is the nonlinear adjustment coefficient, to ensure that Kp is large when the error is large, so as to respond quickly to the error, and Kp decreases when the error decreases to avoid excessive impact. The integral coefficient Ki uses a saturated nonlinear function to limit the integral action and avoid overshoot caused by integral saturation. The formula is as follows: Ki0 is the baseline integral coefficient at the initial startup stage, ensuring that the integral action is gentle and only takes effect when the error is small. The differential coefficient Kd adopts a linearly increasing function, which increases with the increase of the error rate of change ec, as shown in the formula: Where Kd0 is the initial reference differential coefficient and b is the differential adjustment coefficient, which enhances the differential effect and suppresses sudden shocks in torque and current.

5. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in claim 3, characterized in that, For the mid-start-up phase, the proportional coefficient Kp adopts a linearly decreasing function, decreasing linearly with the increase of the engine speed n, as shown in the formula: Where Kp1 is the mid-term baseline ratio coefficient for startup; The integral coefficient Ki adopts a linearly increasing function, increasing linearly with the increase of rotational speed n, as shown in the formula: Ki1 is the baseline integral coefficient during the startup phase (usually 0.8-1.0 times the integral coefficient of a traditional PID controller), which gradually enhances the integral action and eliminates steady-state error. The differential coefficient Kd uses a constant function to maintain a fixed value. Kd1 is the mid-term reference differential coefficient during startup, which maintains the stability of the differential action and suppresses speed oscillation.

6. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact according to claim 3, characterized in that, For the later stages of startup, the proportional coefficient Kp adopts an exponentially decreasing function, decreasing rapidly as the speed n approaches the rated value, as shown in the formula: , where c is the proportional adjustment coefficient, which ensures that Kp is kept at a small level to avoid overshoot; The integral coefficient Ki adopts an exponentially increasing function, increasing rapidly as the rotational speed n approaches its rated value, as shown in the formula: , where d is the integral adjustment coefficient, which enhances the integral effect; The differential coefficient Kd uses a linearly decreasing function, decreasing linearly as the rotational speed n approaches its rated value, as shown in the formula: Kd2 is the baseline differential coefficient in the later stage of startup, which weakens the differential effect and avoids steady-state oscillation.

7. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in claim 3, characterized in that, For the initial stage of shutdown, the proportional coefficient Kp adopts an absolute value exponential function, increasing with the increase of the absolute value of the error |e|, as shown in the formula: Where Kp2 is the initial reference proportional coefficient during shutdown, and a is the nonlinear adjustment coefficient, which quickly responds to deceleration errors and suppresses torque reverse impact. The integral coefficient Ki uses a saturated nonlinear function to limit the integral action, as shown in the formula. Ki2 is the baseline integral coefficient at the initial stage of shutdown, which avoids shutdown shock caused by integral saturation; The differential coefficient Kd adopts a linearly increasing function, which increases as the absolute value of the error rate of change ec increases, as shown in the formula: Where Kd2 is the baseline differential coefficient at the initial shutdown stage, and b is the differential adjustment coefficient (consistent with the initial startup stage) to suppress the impact caused by the rapid drop in speed.

8. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in claim 3, characterized in that, For the mid-term shutdown, the shutdown proportional coefficient Kp adopts a linearly increasing function, increasing linearly as the speed n decreases, as shown in the formula: Kp3 is the mid-term reference ratio coefficient for shutdown, which ensures a smooth transition of Kp and avoids current surges. The integral coefficient Ki adopts a linearly increasing function, increasing linearly as the rotational speed n decreases, as shown in the formula: Ki3 is the baseline integral coefficient during the shutdown process, which gradually enhances the integral effect and facilitates a smooth deceleration process. The differential coefficient Kd uses a constant function to maintain a fixed value. Kd3 is the baseline differential coefficient during the shutdown period, which maintains the stability of the differential action and suppresses speed oscillation.

9. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in claim 3, characterized in that, For the later stages of shutdown, the proportional coefficient Kp adopts an exponentially decreasing function, decreasing rapidly as the rotational speed n decreases, as shown in the formula: Where c is the proportional adjustment coefficient, which ensures that Kp is kept at a small level to avoid sudden motor stoppage; The integral coefficient Ki adopts an exponentially increasing function, increasing rapidly as the rotational speed n decreases, as shown in the formula: , where d is the integral adjustment coefficient, which enhances the integral effect and ensures that the speed is smoothly reduced to 0; The differential coefficient Kd uses a linearly decreasing function, decreasing linearly with decreasing rotational speed n, as shown in the formula: Kd4 is the baseline differential coefficient in the later stage of shutdown, which reduces the differential effect and avoids mechanical shock.

10. The nonlinear PID control strategy for segmented flexible suppression of motor start-stop impact as described in the claims, characterized in that, The control parameters are corrected based on the collected data, including: When the motor stator current exceeds the rated current K1 times, adjust Kp and Ki for the current stage and increase Kd; when the current is lower than the rated current k2 times, adjust Kp and Ki to accelerate the speed response. When the rate of change of the electromagnetic torque of the motor exceeds the threshold of m times / ms of the rated torque, the nonlinear adjustment coefficient is adjusted. The nonlinear condition coefficient is the nonlinear curvature adjustment coefficient, which is used to change the nonlinear change rate and curve shape of the PID parameters in each stage. Combined with the sensitivity of the feedback dynamic correction parameter of the electromagnetic torque, Kp, Ki, and Kd are made to fit the nonlinear change law of different start-stop stages of the motor, thereby improving the shock suppression compliance. After a single start-stop cycle is completed, the baseline parameters for each stage are optimized based on the peak impact, overshoot, and steady-state error to achieve adaptive iterative optimization.

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