阅读说明：本技术 一种抗饱和及抑制超调的控制方法及pi调节器 (Control method for resisting saturation and inhibiting overshoot and PI regulator ) 是由 陈文龙 宁荣华 周青山 苏明 于 2020-07-09 设计创作，主要内容包括：本发明涉及控制器技术领域,特别涉及一种抗饱和及抑制超调的控制方法及PI调节器,其中,一种抗饱和及抑制超调的控制方法,包括确定控制指令与反馈值之间的误差e(k),通过调节系数A和B调整误差e(k)所处的分段区间大小,使用变速积分方法和遇限削弱方法协同调节或改变PI调节器的积分调节控制量,使得PI调节器的输出控制量抑制超调并抗积分饱和。与现有技术相比,本发明提供的一种抗饱和及抑制超调的控制方法,融合变速积分方法和遇限削弱方法,同时改进变速积分的分段系数f[e(k)],通过调节系数A和B调整所述误差e(k)所处的分段区间大小,避免了变速积分系数为零时无积分调节作用,使PI调节器提高了稳态精度同时超调小及响应快。(The invention relates to the technical field of controllers, in particular to a control method for resisting saturation and inhibiting overshoot and a PI (proportional integral) regulator, wherein the control method for resisting saturation and inhibiting overshoot comprises the steps of determining an error e (k) between a control instruction and a feedback value, adjusting the size of a subsection interval where the error e (k) is located through adjusting coefficients A and B, and cooperatively adjusting or changing an integral adjustment control quantity of the PI regulator by using a variable speed integral method and a meet limit weakening method to enable the output control quantity of the PI regulator to inhibit overshoot and resist integral saturation. Compared with the prior art, the control method for resisting saturation and inhibiting overshoot integrates a variable speed integral method and a meeting limit weakening method, improves a segment coefficient f [ e (k) ] of variable speed integral, adjusts the segment interval size of the error e (k) through adjusting the coefficients A and B, avoids no integral adjustment function when the variable speed integral coefficient is zero, and enables a PI regulator to improve steady-state precision and simultaneously achieve small overshoot and fast response.)

1. A control method for resisting saturation and inhibiting overshoot is characterized by comprising the following steps: determining an error e (k) between a control instruction and a feedback value, adjusting the size of a subsection interval where the error e (k) is located through adjusting coefficients A and B, and cooperatively adjusting or changing an integral adjusting control quantity of a PI regulator by using a variable speed integral method and a meet limit weakening method so that the output control quantity of the PI regulator inhibits overshoot and resists integral saturation.

2. The method of claim 1, wherein the method further comprises: the variable-speed integration method is used for changing the accumulation speed of an integral term to be adaptive to the error e (k) by setting a variable-speed integral coefficient f [ e (k) ], and adjusting or changing the integral adjustment control quantity of the PI regulator.

3. The anti-saturation and overshoot suppression control method according to claim 2, wherein the variable speed integration method comprises the steps of:

s101: judging whether | e (k) | is less than or equal to B;

s102: when | e (k) | ≦ B, then f [ e (k) ] — 1; when | e (k) | > B, judging whether | e (k) | is less than or equal to A + B;

s103: when | e (k) ≦ a + B, then f [ e (k) } ═ a +1+ B- | e (k) |)/(a + 1); when | e (k) | > a + B, then f [ e (k) ] ═ 1/[ ((a + B)/| e (k) |) × (| e (k) | -B +1) ].

4. The method of claim 3, wherein the step of controlling the anti-saturation and overshoot suppression comprises: a > 0 and B > 1.

5. The method of claim 4, wherein the step of controlling the anti-saturation and overshoot suppression comprises: the control method further comprises deriving a proportional term from Kp × e (k).

6. The method of claim 5, wherein the step of controlling the anti-saturation and overshoot suppression comprises: the meet limit weakening method judges whether the last PI output control quantity exceeds the limit value, and when the last PI output control quantity exceeds the limit value, the error e (k) with opposite integral accumulation signs is carried out so that the PI regulator outputs the control quantity to resist integral saturation.

7. The method of claim 6, wherein the over-ride mitigation method comprises the steps of:

s201: judging whether U (k-1) is more than or equal to Umax, executing the step S202 when U (k-1) is more than or equal to Umax, and executing the step S203 when U (k-1) < Umax;

s202: judging whether e (k) is more than 0, when e (k) is more than 0, beta is 0, and when e (k) is less than or equal to 0, beta is 1;

s203: judging whether U (k-1) is less than or equal to Umin, executing step S204 when U (k-1) is less than or equal to Umin, and when U (k-1) is greater than Umin, beta is 1;

s204: and (3) judging whether e (k) < 0, if e (k) < 0, beta is 0, and if e (k) ≧ 0, beta is 1.

8. The control method of claim 7, wherein after S204, the control method further comprises the steps of:

s301: obtaining a current integral term through Ki multiplied by f [ e (k) ]multipliedby e (k) × beta;

s302: obtaining a PI output control quantity u (k) by a sum of the proportional term, the current integral term and the last integral term, and u (k) ═ Kp (k) + Ki × f [ e (k) ] × e (k) + β + Ui (k-1);

s303: the previous integral term Ui (k-1) is updated, and the previous integral term Ui (k-1) Ki × f [ e (k) ] · (k) × β + Ui (k-1).

9. The method of claim 8, wherein the step of controlling the anti-saturation and overshoot suppression comprises: u (k-1) is the last PI output control quantity; umax is the upper limit value of PI output, and Umin is the lower limit value of PI output; beta is a PI output saturation coefficient, and beta is used for controlling the current integration in the variable speed integration method to obtain the current integration term.

10. A PI regulator employing a control method of anti-saturation and overshoot suppression as claimed in any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of controllers, in particular to a control method for resisting saturation and inhibiting overshoot and a PI (proportional-integral) regulator.

Background

The purpose of industrial controller design is to make the controlled object operate according to the required target, or to make the controlled object have the expected response. In practical control systems, various limitations often exist, such as limitations on temperature, pressure, flow, and level in process control, and limitations on voltage, current, torque, and speed in motor systems.

Proportional integral (PI regulator) or proportional integral derivative (PID regulator), because its regulation rule is simple, easy to implement, and does not need accurate controlled object mathematical model, it can be used as most extensive controller in industrial process. The PI regulator can linearly combine the proportion and the integral of the deviation to form a control quantity according to the control deviation formed by the given value and the actual output value, and control the controlled object. The integral action in the PI regulator can eliminate the static difference, but the integral saturation phenomenon can be generated; integral saturation can cause large system overshoot, long transition time, poor closed loop response, and in severe cases, accidents.

Although chinese patent (publication No. CN103391015B) discloses a parameter adjusting method for a variable parameter PI regulator, which adjusts a proportional adjustment coefficient Kp according to an error condition, in the process of controlling a PWM rectifier by a parameter, both dynamic performance and steady-state performance are considered. However, when the accumulated error is too large, the speed-changing integral coefficient is zero, and no integral effect exists, so that the accumulated error reaches integral saturation when the error is too large, and the overshoot becomes large and the transition time becomes long.

Disclosure of Invention

In order to solve the problem that the variable speed integral coefficient is zero and has no integral effect when the error is overlarge in the prior art, so that the error is overlarge to reach integral saturation, the invention provides the control method for preventing saturation and inhibiting overshoot and the PI regulator, which avoid the phenomenon of integral zero and simultaneously enable the output of the PI regulator to inhibit overshoot and prevent integral saturation.

The invention provides a control method for resisting saturation and inhibiting overshoot, which comprises the following steps: determining an error e (k) between a control command and a feedback value, adjusting the size of a subsection interval where the error e (k) is located through adjusting coefficients A and B, and cooperatively adjusting or changing an integral adjusting control quantity of an P I regulator by using a variable speed integral method and a meet limit weakening method, so that the output control quantity of the PI regulator inhibits overshoot and resists integral saturation.

Further, the variable-speed integration method is used for changing the accumulation speed of an integral term to be adaptive to the error e (k) by setting a variable-speed integral coefficient f [ e (k) ], and adjusting or changing the integral adjustment control quantity of the P I regulator.

Further, the variable speed integration method includes the steps of:

s101: judging whether | e (k) | is less than or equal to B;

s102: when | e (k) | ≦ B, then f [ e (k) ] — 1; when | e (k) | > B, judging whether | e (k) | is less than or equal to A + B;

s103: when | e (k) ≦ a + B, then f [ e (k) } ═ a +1+ B- | e (k) |)/(a + 1); when | e (k) | > a + B, then f [ e (k) ] ═ 1/[ ((a + B)/| e (k) |) × (| e (k) | -B +1) ].

Further, A > 0, B > 1.

Further, the control method further comprises deriving a proportional term from Kp × e (k).

Further, the meet limit weakening method judges whether the last PI output control quantity exceeds a limit value, and when the last PI output control quantity exceeds the limit value, the error e (k) with opposite integral accumulation signs is integrated, so that the PI regulator output control quantity is prevented from integral saturation.

Further, the encounter-bound attenuation method comprises the following steps:

s201: judging whether U (k-1) is more than or equal to Umax, executing the step S202 when U (k-1) is more than or equal to Umax, and executing the step S203 when U (k-1) < Umax;

s202: judging whether e (k) is more than 0, when e (k) is more than 0, beta is 0, and when e (k) is less than or equal to 0, beta is 1;

s203: judging whether U (k-1) is less than or equal to Umin, executing step S204 when U (k-1) is less than or equal to Umin, and when U (k-1) is greater than Umin, beta is 1;

s204: and (3) judging whether e (k) < 0, if e (k) < 0, beta is 0, and if e (k) ≧ 0, beta is 1.

Further, after S204, the control method further includes the steps of:

s301: obtaining a current integral term through Ki multiplied by f [ e (k) ]multipliedby e (k) × beta;

s302: obtaining a PI output control quantity u (k) by a sum of the proportional term, the current integral term and the last integral term, and u (k) ═ Kp (k) + Ki × f [ e (k) ] × e (k) + β + Ui (k-1);

s303: the previous integral term Ui (k-1) is updated, and the previous integral term Ui (k-1) Ki × f [ e (k) ] · (k) × β + Ui (k-1).

Further, U (k-1) is the last PI output control quantity; umax is the upper limit value of PI output, and Umin is the lower limit value of PI output; beta is a PI output saturation coefficient, and beta is used for controlling the current integration in the variable speed integration method to obtain the current integration term.

The invention also provides a PI regulator adopting the control method for resisting saturation and inhibiting overshoot.

Compared with the prior art, the control method for resisting saturation and inhibiting overshoot and the PI regulator provided by the invention have the advantages that the size of the subsection interval where the error e (k) is located is adjusted through the adjusting coefficients A and B according to the error between the control instruction and the feedback value, the integral adjusting control quantity of the PI regulator is cooperatively adjusted or changed by using the variable speed integral method and the threshold weakening method, the integral adjusting effect is avoided when the variable speed integral coefficient is zero, the integral saturation phenomenon is avoided, the overshoot quantity and the response time of large step input are further reduced, and the stable state precision of the PI regulator is improved, and the overshoot is small and the response speed is high.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic flow chart of a control method for anti-saturation and overshoot suppression according to the present invention;

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a control method for resisting saturation and inhibiting overshoot, which comprises the following steps: determining an error e (k) between a control command and a feedback value, adjusting the size of a subsection interval where the error e (k) is located through adjusting coefficients A and B, and cooperatively adjusting or changing an integral adjusting control quantity of an P I regulator by using a variable speed integral method and a meet limit weakening method, so that the output control quantity of the PI regulator inhibits overshoot and resists integral saturation.