CN114421769A - DC converter robust self-adaptive disturbance rejection control method based on immersion and invariance theory - Google Patents

DC converter robust self-adaptive disturbance rejection control method based on immersion and invariance theory Download PDF

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CN114421769A
CN114421769A CN202111680709.7A CN202111680709A CN114421769A CN 114421769 A CN114421769 A CN 114421769A CN 202111680709 A CN202111680709 A CN 202111680709A CN 114421769 A CN114421769 A CN 114421769A
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converter
disturbance
disturbance rejection
fault
immersion
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皇甫宜耿
徐良材
卓生荣
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Northwestern Polytechnical University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection

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Abstract

The invention relates to a direct current converter robust adaptive disturbance rejection control method based on immersion and invariance theory. The method is based on the original linear active disturbance rejection controller, and utilizes immersion and invariance theories to realize online estimation by measuring output voltage on line and simultaneously adopting total disturbance estimated by an extended state observer in real time and control variables calculated by a voltage outer loop. The method is not intended to give accurate system parameters, but can enable the given system parameters to change in the direction of improving the dynamic response of the system on line according to the change trend of the controlled variables, and improve the capacity of resisting external disturbance of the whole system. The invention designs input voltage step disturbance, output load step disturbance and disturbance at fault moment starting from two conditions of the converter, namely health and fault. Experimental results show that the method has stronger robust capability than the traditional linear active disturbance rejection controller in both a healthy state and a fault state.

Description

DC converter robust self-adaptive disturbance rejection control method based on immersion and invariance theory
Technical Field
The invention belongs to the field of control science and control engineering, and provides a robust anti-interference controller with self-adaptive capacity, which is applied to a direct-current converter.
Background
With the gradual depletion of fossil fuels, clean energy power generation systems such as wind power generation systems, photovoltaic power generation systems, and fuel cell power generation systems have received much attention. In these renewable energy systems, the dc converter plays an important role in energy conversion at all times. However, dc converters are strongly nonlinear systems, and it is difficult to design a suitable controller for them. In addition, in new energy systems such as photovoltaic power generation and wind power generation, the output voltage and power of the new energy systems are greatly affected by the external weather, so that the voltage and current of the input end of the direct current converter can be disturbed unpredictably, which brings a serious challenge to the stable optimization control of the converter. In the actual operation process, the working performance of the converter is also disturbed by the severe disturbance of the load of the output end and the uncertainty of parameters of the power device caused by aging. In addition, in a more severe working environment, the dc converter may cause a breakdown of the entire system due to device failure. Therefore, in order to improve the working performance of the whole new energy system, a controller with high robustness needs to be designed on the basis of considering all the emergencies.
In the development process of the control theory in the past decades, a series of advanced nonlinear control strategies are developed, and the control strategies mainly comprise sliding mode control, robust control, adaptive control, optimal control, disturbance rejection control, fuzzy logic control and artificial intelligence control. Although in academic research and laboratory environments, these control theories can achieve performance far beyond that of traditional controllers, it is often difficult to land in actual engineering practice. At present, the active disturbance rejection control method is greatly expected by a great number of engineering practitioners. The active disturbance rejection control is firstly proposed by Mr. Han Jingqing, and is popularized by deeply thinking a traditional proportional-integral controller and combining the concepts of a state space and an observer in the modern control theory. The active disturbance rejection control created by mr. hangul shows good control performance, but many parameters are involved in the actual design process, and the complexity of the parameter adjusting process hinders the application of the active disturbance rejection control in engineering practice. After that, under the effort of the high-minded teacher, the active disturbance rejection controller is successfully modified into a linear form, and the controller parameters are also reduced to two, which greatly pushes the application of the theory.
Theoretical and practical results show that the control performance of the linear active disturbance rejection control depends on the performance of an observer of the linear active disturbance rejection control. The traditional linear active disturbance rejection controller adopts a linear extended state observer with fixed gain and fixed frequency, and the working performance of a controlled object under large disturbance and wide-frequency external disturbance cannot be ensured. Thus, documents s.zhuo, a.gaillard, l.guo, l.xu, d.pair and f.gao, "Active Disturbance Rejection Voltage Control of a flowing interfered DC-DC Boost Converter With Switch Fault coordination," in IEEE Transactions on Power Electronics, vol.34, No.12, pp.12396-12406, dec.2019 propose a method in which the gain of the extended state observer is adaptively changed according to the change of the system operating state. Compared with the traditional linear active disturbance rejection controller, the method can greatly improve the working performance of the converter system, but the design of the method is seriously dependent on the physical model of the controlled object, and different physical models need to be constructed for different controlled objects, so the method has no generality.
Disclosure of Invention
Technical problem to be solved
In order to overcome the limitation of the traditional linear active disturbance rejection controller in the control of the direct current converter, the invention provides a more general robust adaptive disturbance rejection control method which does not depend on the actual physical model of the controlled object. The method can improve the capability of resisting disturbance of internal parameters and external disturbance of the direct current converter in a normal working state, and simultaneously ensure that the direct current converter can still keep a good working state in a fault state.
Technical scheme
A DC converter robust self-adaptive disturbance rejection control method based on immersion and invariance theory is characterized by comprising the following steps:
the method comprises the following steps: respectively constructing state space equations of the direct current converter in a healthy state and a fault state of the switching tube;
step two: designing a cascade control structure based on a voltage outer ring and a current inner ring aiming at the direct current converter; firstly, designing a current inner ring by adopting a sliding mode control theory, and providing a closed-loop transfer function of the current inner ring of the converter by utilizing an ideal sliding mode linearization concept;
step three: aiming at the current inner loop closed-loop transfer function obtained in the step two, an extended state observer is designed by utilizing the traditional linear active disturbance rejection control theory to estimate the total disturbance inside and outside the system;
step four: aiming at the total system disturbance obtained in the step three, designing a proportional controller according to a preselected control bandwidth, and completing the design process of the whole traditional active disturbance rejection controller;
step five: on the basis of the traditional linear active disturbance rejection controller, the on-line real-time estimation of the system gain parameters is realized on the basis of immersion and invariance theories, and the design process of the proposed robust adaptive disturbance rejection control method is completed.
The further technical scheme of the invention is as follows: the state space equation in the step one:
when the converter is operating in a healthy state:
Figure BDA0003437599080000031
wherein L is1,L2Input inductance values of the two-phase circuit, respectively; rL1,RL2Parasitic resistances of the two input inductors are respectively; c1,C2Respectively the output capacitance values of the two circuits; i.e. iL1,iL2The currents respectively flow through the two paths of inductors; v. ofc1,vc2The voltages at two ends of the two paths of output capacitors are respectively; l is1＝L2＝L,C1＝C2＝C,vc1＝vc2＝vc,iL1＝iL2＝iL；dHFor duty cycle definition in the healthy state, R denotes the equivalent load resistance;
when the converter is operating in a fault condition:
Figure BDA0003437599080000032
wherein d isFRepresenting the duty cycle, v, of the converter after fault reconstructiono＝vc1+vc2；
The further technical scheme of the invention is as follows: the inner loop closed loop transfer function in the step two:
when the converter is operating in a healthy state:
Figure BDA0003437599080000033
wherein the content of the first and second substances,
Figure BDA0003437599080000041
Vinfor input of current, ILrefIs a reference current;
when the converter is operating in a fault condition:
Figure BDA0003437599080000042
wherein the content of the first and second substances,
Figure BDA0003437599080000043
the further technical scheme of the invention is as follows: the total disturbance inside and outside the system in the step three is designed as follows:
Figure BDA0003437599080000044
wherein when the converter is in a healthy state, b is equal to b1,
Figure BDA0003437599080000045
y＝vo(ii) a When the converter has b-b in fault state2,
Figure BDA0003437599080000046
y＝vc(ii) a b represents a system of transducersThe parameter, f, represents the total disturbance of the converter system.
The further technical scheme of the invention is as follows: the proportional controller in step four:
Figure BDA0003437599080000047
wherein k ispFor proportional control term gain, VrefIs the converter reference voltage.
Advantageous effects
The invention provides a direct current converter robust self-adaptive disturbance rejection control method based on immersion and invariance theories. The method is based on the original linear active disturbance rejection controller, and utilizes immersion and invariance theories to realize online estimation by measuring output voltage on line and simultaneously adopting total disturbance estimated by an extended state observer in real time and control variables calculated by a voltage outer loop. The method is not intended to give accurate system parameters, but can enable the given system parameters to change in the direction of improving the dynamic response of the system on line according to the change trend of the controlled variables, and improve the capacity of resisting external disturbance of the whole system. The method can be applied to various direct current converters to improve the working performance of the controlled object under internal and external disturbances and unknown potential faults.
In order to verify the superiority of the method, a typical input parallel output series type boost converter is taken as a research object, and input voltage step disturbance, output load step disturbance and disturbance at the moment of fault are designed respectively from the beginning of the converter under two conditions of health and fault. Experimental results show that the method has stronger robust capability than the traditional linear active disturbance rejection controller no matter in a healthy state or a fault state, and compared with the prior art, the method has the following steps:
(1) compared with the traditional linear active-disturbance-rejection control method, the method can improve the capability of resisting disturbance of internal parameters, disturbance of external input voltage and disturbance of external load of the direct-current converter in a normal working state;
(2) compared with the traditional linear active disturbance rejection control method, the method can greatly improve the capability of the direct current converter for resisting internal and external disturbance in a fault reconstruction state, and can also improve the performance of the converter at the moment of fault occurrence.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.
FIG. 1 shows a topology of an input parallel output series DC boost converter, (a) a topology in a healthy state, and (b) S1Reconstruction of topology under fault, (c) S2Reconstructing a topological structure under the fault;
FIG. 2 is a block diagram of the overall control of the proposed control method in an input parallel output series DC boost converter;
FIG. 3 is a typical input parallel output series DC boost converter experimental test platform;
fig. 4 is an experimental diagram of the step disturbance of the input voltage of the converter in a healthy state: (a) a conventional active disturbance rejection controller, (b) the proposed adaptive disturbance rejection controller;
fig. 5 is an experimental diagram of input voltage step disturbance of the converter in a fault state: (a) a conventional active disturbance rejection controller, (b) the proposed adaptive disturbance rejection controller;
fig. 6 is a diagram of a load current step disturbance experiment of the converter in a healthy state: (a) a conventional active disturbance rejection controller, (b) the proposed adaptive disturbance rejection controller;
fig. 7 is a load current step disturbance experimental diagram of the converter in a fault state: (a) a conventional active disturbance rejection controller, (b) the proposed adaptive disturbance rejection controller;
fig. 8 is an experimental diagram for verifying the disturbance rejection capability of the converter at the moment of failure: (a) a conventional active disturbance rejection controller, and (b) the proposed adaptive disturbance rejection controller.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The invention provides a robust self-adaptive anti-interference control method based on immersion and invariance theories, which comprises the following steps.
The method comprises the following steps: respectively constructing state space equations of the direct current converter in a healthy state and a fault state of the switching tube, and laying a foundation for the design of a subsequent controller;
step two: a cascade control structure based on a voltage outer ring and a current inner ring is designed for a direct current converter. Because the method mainly aims at the control of the voltage outer ring, the current inner ring is designed by adopting a sliding mode control theory, and the closed-loop transfer function G of the current inner ring of the converter is given by utilizing the ideal sliding mode linearization conceptie(s)；
Step three: aiming at the current inner loop closed-loop transfer function obtained in the step two, designing an extended state observer by utilizing a traditional linear active disturbance rejection control theory to estimate the total disturbance f inside and outside the system;
step four: aiming at the total system disturbance obtained in the step three, designing a proportional controller according to a preselected control bandwidth, and completing the design process of the whole traditional active disturbance rejection controller;
step five: on the basis of the traditional linear active disturbance rejection controller, the system gain parameter b is estimated on line in real time based on immersion and invariance theories, and the design process of the provided robust adaptive disturbance rejection control method is completed.
In order that those skilled in the art will better understand the present invention, the following detailed description is given with reference to specific examples.
Referring to fig. 1, 2 and 3, the implementation steps of the present invention are as follows.
The invention provides a direct current converter robust self-adaptive disturbance rejection control method based on immersion and invariance theories, which mainly comprises the following five steps.
The method comprises the following steps: construction ofAnd inputting a state space model of the parallel output serial direct current boost converter in a healthy state and a fault state. As can be seen from FIG. 1, both the switching tube S and the switching tube S1Fault or switch tube S2And when the fault occurs, the topological structures of the direct current converters after the fault reconstruction are consistent, so that the state space models of the converters in the fault state can be uniformly expressed.
When the converter is operating in a healthy state:
Figure BDA0003437599080000071
wherein L is1,L2Input inductance values of the two-phase circuit, respectively; rL1,RL2Parasitic resistances of the two input inductors are respectively; c1,C2Respectively the output capacitance values of the two circuits; i.e. iL1,iL2The currents respectively flow through the two paths of inductors; v. ofc1,vc2The voltages at two ends of the two paths of output capacitors are respectively; d1,d2The duty cycle of the two-phase circuit. In the present invention, the control of the two-phase circuits is realized by separate controllers, respectively, and the system control after the failure is performed by the control of the healthy phase circuit. In order to facilitate the weakening of the requirement of completely equal voltage at two ends of the output capacitor, a single voltage controller is adopted to realize the adjustment of the voltage of the two-phase circuit. Meanwhile, for the convenience of subsequent analysis and design, it is assumed that two-phase circuits are completely consistent and have L1＝L2＝L,C1＝C2＝C,RL1＝RL2＝r,vc1＝vc2＝vc,iL1＝iL2＝iL,d1＝d2D, then equation (1) can be simplified as:
Figure BDA0003437599080000072
wherein, in order to distinguish the duty ratio of the converter in the healthy state from the duty ratio of the converter in the fault state, the duty ratio of the converter in the healthy state is defined as dHAnd R denotes an equivalent load resistance.
When the converter is operating in a fault condition:
when a fault occurs, the original input-parallel output-series direct-current boost converter is reconstructed into a traditional direct-current boost converter due to the action of a fault-tolerant control strategy. Under the view angle of an inner ring controller, the input inductance value and the output capacitance value of the converter are reduced by half after the fault reconstruction, and the output voltage is doubled. On the basis of the phenomenon, the state space equation of the converter after fault reconstruction can be obtained as follows:
Figure BDA0003437599080000081
wherein d isFRepresenting the duty cycle, v, of the converter after fault reconstructiono＝vc1+vc2；
Step two: aiming at a current inner ring and voltage outer ring cascade control structure adopted by a direct current converter, a current inner ring controller is designed by applying a sliding mode variable control theory. And then, obtaining the closed loop transfer function of the inner loop current of the direct current converter by using an ideal sliding mode linearization method. Because the inner ring current controller based on the sliding mode theory is not the protection point of the invention, the detailed process is omitted, and the inner ring current closed-loop transfer function G of the direct current converter in the healthy and fault states is directly givenie(s)：
(1) When the converter is operating in a healthy state:
Figure BDA0003437599080000082
wherein the content of the first and second substances,
Figure BDA0003437599080000083
Vinfor input of current, ILrefIs a reference current;
(2) when the converter is operating in a fault condition:
Figure BDA0003437599080000084
wherein the content of the first and second substances,
Figure BDA0003437599080000085
Vinfor input of current, ILrefIs a reference current;
this makes it possible to obtain before and after a fault: a is1＝2a2,b1＝2b2,c1＝2c2. Therefore, appropriate parameters of the sliding mode controller can be selected to ensure that the direct current converter can work well before and after the fault.
Step three: and (3) aiming at the current inner loop closed-loop transfer function obtained in the step two, designing an extended state observer by utilizing a traditional linear active disturbance rejection control theory to estimate the total disturbance f inside and outside the system, wherein the detailed design process is as follows.
According to the derivation of the closed-loop transfer function of the current inner loop of the converter in the step two, a uniform expression form aiming at the outer loop controller can be obtained:
Figure BDA0003437599080000091
defining the output of the converter in a healthy state as y ═ vcAnd the output under fault reconstruction is y ═ voThe controlled variable is u ═ ILref. Thus, the following expression can be obtained:
Figure BDA0003437599080000092
wherein when the converter is in a healthy state, b is equal to b1,
Figure BDA0003437599080000093
y＝vo(ii) a When the converter has b-b in fault state2,
Figure BDA0003437599080000094
y＝vc. b represents the system parameters of the converter and f represents the total disturbance of the converter system.
To facilitate the design of the controller, equation (7) is converted into a state space form. The variable defining this state space is x ═ x1 x2]T＝[y f]Thus, equation (7) can be rewritten as:
Figure BDA0003437599080000095
where h is the first derivative of the total disturbance of the system, an unknown but bounded variable.
In order to construct a proper linear active disturbance rejection controller, a linear extended state observer can be designed to observe the total disturbance and the state variable of the system in real time:
Figure BDA0003437599080000096
wherein z is1And z2Are observed variables for variables y and f, respectively.
From equation (9), the characteristic equation of the linear extended state observer can be obtained as:
p(s)＝s2+β1s+β2 (10)
in order to make two characteristic roots of the observer characteristic equation all located at-omega0Is (omega)0To linearly expand the bandwidth value of the state observer), the observer parameter β can be made1,β2The values of (A) are respectively as follows:
Figure BDA0003437599080000097
to more intuitively design a suitable bandwidth value for the linear extended state observer, equation (9) can be rewritten to the form of z-domain:
Figure BDA0003437599080000098
wherein e isrr(k)＝y(k)-z1(k),β1s＝Tsβ1,β2s＝Tsβ2。β1sAnd beta2sThe value of (c) will affect the distribution of the closed loop poles of the system and thus the stability of the system. Therefore, these two parameters need to be carefully designed to meet the system stability and overall controller effectiveness. According to equation (12), the transfer function of the extended state observer can be found as:
Figure BDA0003437599080000101
the characteristic equation of equation (13) is:
z2+(β1s-2)z+1-β1s+β2sTs0 (14) taking into account β1s＝2ω0Ts,
Figure BDA0003437599080000102
The characteristic root of the transfer function g (z) can therefore be solved as:
z1,2＝1-ω0Ts(15) thus, the bandwidth of the linear extended state observer can be found as:
Figure BDA0003437599080000103
at this point, the bandwidth value of the system is determined by analyzing the unit circle effect in the z-domain. So far, the system unknown disturbance f in the equation (7) can be well estimated and effectively suppressed by the method of feedforward compensation.
Step four: aiming at the observed value z of the total system disturbance f obtained in the step three2Designing a proportional controller according to a preselected control bandwidthThe detailed design process of the whole traditional active disturbance rejection controller is as follows.
The observed value z of f obtained from equation (7) and step three2The controller expression that may define the outer loop of the converter voltage is:
Figure BDA0003437599080000104
wherein u is0A feedback control mechanism is introduced for ensuring the closed loop stability of the linear active disturbance rejection controller. The feedback controller of the converter voltage outer loop is assumed to be only a proportional link, namely:
u0＝kp(Vref-z1)≈kp(Vref-vo) (18)
wherein, VrefIs the converter reference voltage. Thus, when the linear extended state observer can perform dynamic tracking on the total system disturbance well, equation (7) can be abbreviated as:
Figure BDA0003437599080000111
wherein k ispThe value of the proportional control term gain can be determined by implementing a well-defined system controller bandwidth.
Since the converter is in either a healthy state or a fault state, y-voAll the requirements are met. Thus, it can be concluded that: under the action of the designed voltage outer ring linear active disturbance rejection controller, the output voltage of the converter can be globally and gradually stabilized no matter whether the converter fails or not.
Step five: on the basis of a traditional linear active disturbance rejection controller, on-line real-time estimation is carried out on a system gain parameter b based on an immersion and invariance theory, and the design process of the proposed robust adaptive disturbance rejection control method is completed, and the detailed design process is as follows.
Let the estimated value of the system parameter b be bI+bp(y), then the error between the estimated value and the true value can be solved as:
ξ＝bI+bp(y)-b (20)
when the error ξ between the estimated value of the parameter b and its true value converges to zero, the estimated value can be used directly in the design process of the linear active disturbance rejection controller.
The derivation is performed on both sides of the equation of equation (20) separately, as follows:
Figure BDA0003437599080000112
if get
Figure BDA0003437599080000113
Equation (21) can be further simplified as:
Figure BDA0003437599080000114
to ensure that the estimation error xi can reach gradual convergence in the global range, b can be calculatedp(y) is defined as follows:
bp＝ρy (24)
where ρ is a constant greater than zero and represents the rate at which the estimation error ξ converges.
B is topWhen the value of (y) is substituted into the formula (22), the dynamic equation of the observer can be obtained as follows:
Figure BDA0003437599080000121
therefore, the invention realizes the difficult problems that the system parameter b in the traditional linear active disturbance rejection controller is difficult to be accurate at two sides, the online identification is complex and the universality is lacked, and the real-time online estimation of the parameter b can be realized on the basis of the formula (7) by utilizing the immersion and invariance theory, and the detailed design block diagram is shown in fig. 2. The estimation method does not depend on a system model and a large amount of data, and has simple and practical parameter adjustment and wide universality.
The effects of the present invention will be further described by the following experiments.
(1) Conditions of the experiment
The direct current converter robust adaptive disturbance rejection control method based on the immersion and invariance theory provided by the invention is applied to a typical input-parallel output series direct current boost converter, and the topological structure diagram of the converter is shown in figure 1. The main parameters of the converter in the experiment were: inductor L1＝L21000 muH, capacitance C1＝C2470 muF, output voltage Vin48V and a switching frequency of 25 kHz. The proposed control method will be run in dSPACE 1007 with an experimental platform diagram as shown in figure 2.
(2) Content of the experiment
A typical input-parallel output series-connection type direct current boost converter is taken as a test object, and the advantages of the provided direct current converter robust adaptive anti-interference control method based on the immersion and invariance theory compared with the traditional linear active-interference controller are verified. The method mainly comprises five experimental contents: the method comprises the steps of input voltage step disturbance of the converter in a healthy state, input voltage step disturbance of the converter in a fault state, load current step disturbance of the converter in the healthy state, load current step disturbance of the converter in the fault state and disturbance rejection capability verification of the converter at the moment of fault.
The first experimental content is as follows:
under a healthy state, the boost capacity of the converter is higher, the input voltage is designed to jump in a periodic step mode between 6V and 14V, each voltage lasts for 500ms, the period is 1s, the output reference voltage is still 48V at the moment, and the load required current is set to be 1A.
In the healthy state of the converter, the experimental result corresponding to the conventional linear active-disturbance-rejection controller is shown in fig. 4(a), and it can be seen from the figure that the conventional linear active-disturbance-rejection controller can ensure that the output voltage is maintained at the reference voltage of 48V when the input voltage is stable, and when the input voltage is stepped from 6V to 14V, the output voltage is adjusted upwards, the maximum voltage is 52.8V, and the recovery time is 66.5 ms; when the input voltage is stepped from 14V to 6V, the output voltage is adjusted downwards, the lowest voltage is 45.6V, and the recovery time is 45.6 ms.
The experimental results of the proposed controller in the healthy state of the converter are shown in fig. 4(b), and it can be seen that, under the given step disturbance of the input voltage, the proposed adaptive immunity controller can also ensure that the output voltage is maintained at the reference voltage 48V when the input voltage is stable, and the voltage fluctuation amplitude is smaller due to the dynamic change of b (from 488 to 872 with the period 1 s). When the load current jumps from 2A to 1A, the output voltage is subjected to an up-regulation phenomenon, the maximum voltage is 50V, and the recovery time is 31.1 ms; when the load current jumps from 1A to 2A, the output voltage is adjusted downwards, the minimum voltage is 46.8V, and the recovery time is 39.4 ms.
And (2) experimental contents II:
after the converter fails, its boost capability decreases, with the input voltage step disturbance set to a periodic disturbance between 10V and 18V, each voltage level lasting 500ms for a period of 1 s. The reference value of the output voltage is still set to 48V and the load demand current is 1A.
The experimental result corresponding to the conventional linear active-disturbance-rejection controller in the converter fault state is shown in fig. 5(a), and it can be seen from the figure that, under the given input voltage step disturbance, the conventional linear active-disturbance-rejection controller can ensure that the output voltage is maintained at the reference voltage of 48V when the input voltage is stable, and when the input voltage is stepped and jumped from 10V to 18V, the output voltage is up-regulated, the maximum voltage is 51.6V, and the recovery time is 47.1 ms; when the input voltage jumps from 18V step to 10V, the output voltage is adjusted downwards, the lowest voltage is 45.6V, and the recovery time is 62.2 ms.
The experimental results of the proposed controller in the converter fault state are shown in fig. 5(b), and it can be seen that, under the given input voltage step disturbance, the proposed adaptive immunity controller can also ensure that the output voltage is maintained at the reference voltage 48V when the input voltage is stable, and the voltage fluctuation amplitude is smaller due to the dynamic change of b (from 408 to 632 in the period 1 s). When the input voltage jumps from 10V to 18V, the output voltage is subjected to an up-regulation phenomenon, the highest voltage is 49.2V, and the recovery time is ignored; when the input voltage jumps from 18V to 10V, the output voltage is adjusted downwards, the lowest voltage is 47.6V, and the recovery time is also negligible.
TABLE 1 analysis of input Voltage step disturbance test results
Figure BDA0003437599080000141
According to the analysis of the first experimental content and the second experimental content, both the controllers can ensure that the output voltage of the converter is maintained near the reference voltage 48V under the condition of input voltage step disturbance whether in a fault state or a healthy state. Specific differences are summarized in table 1. Compared with the traditional controller, the method has stronger disturbance rejection capability, smaller voltage difference of output voltage and shorter recovery time.
Experiment contents are three:
under the condition of load current step disturbance, the load current is set to be I no matter the converter is in a healthy or fault state o1A → 2A → 1A, the input voltage is 12V and the output voltage reference value is 48V.
In the healthy state of the converter, the experimental result corresponding to the conventional linear active-disturbance-rejection controller is shown in fig. 6(a), and it can be seen from the graph that, under the given load current step disturbance, the conventional linear active-disturbance-rejection controller can ensure that the output voltage is maintained near the reference voltage 48V, the maximum voltage is 54.4V, and the recovery time is 37.9 ms; the minimum voltage is 42.4V, the recovery time is 35.7ms, and the fluctuation period is 1 s.
The experimental result of the proposed controller in the healthy state of the converter is shown in fig. 6(b), and it can be seen that, under the given load current step disturbance, the proposed adaptive immunity controller maintains the output bus voltage at about 48V, and due to the dynamic change of b (fluctuating from 488 to 760 in a period of 1 s), the voltage fluctuation range is smaller, the maximum voltage is 50.8V, and the recovery time is 19.8 ms; the minimum voltage was 45.2V and the recovery time was 20.7 ms.
The experimental content is four:
the experimental result of the conventional linear active-disturbance-rejection controller in the fault state of the converter is shown in fig. 7(a), and it can be seen from the figure that, under the given load current step disturbance, the conventional linear active-disturbance-rejection controller can ensure that the output voltage fluctuates by a small amplitude on the basis of 48V, wherein the maximum voltage is 56.8V, and the recovery time is about 81.9 ms; the minimum voltage was 40.4V and the recovery time was 41.6 ms.
The experimental result of the proposed controller in the converter fault state is shown in fig. 7(b), and it can be seen that, under the given load current step disturbance, the proposed adaptive immunity controller maintains the output voltage around 48V with smaller fluctuation amplitude (fluctuation is performed in 1s period from 256 to 456), the maximum voltage is 50.1V, and the recovery time is 14.4ms due to the dynamic change of b; the minimum voltage was 46.1V and the recovery time was 20.7 ms.
TABLE 2 analysis of load current step disturbance experiment results
Figure BDA0003437599080000151
According to the analysis of the third experimental content and the fourth experimental content, both the controllers can ensure that the output voltage of the converter always keeps fluctuating around the reference voltage 48V under the condition of output load step disturbance in both the fault state and the healthy state. Specific differences are summarized in table 2. Compared with the traditional controller, the method has stronger disturbance rejection capability, smaller voltage difference of output voltage and shorter recovery time, and the method has stronger robustness capability compared with the traditional linear active disturbance rejection controller.
And (5) experiment contents are as follows:
when the main switch device in the power converter has open-circuit fault, the total equivalent input inductance and the equivalent output capacitance of the converter are both in value due to the reconstruction effectWith half of the dip, the system parameter b for the linear active disturbance rejection controller also changes abruptly. These changes have a severe impact on the dynamic effects of system control. Here with a power switch tube S2For example, when an open-circuit fault occurs, the system response capability of the method at the moment of the fault is improved. At the moment of fault occurrence, the converter input voltage is 12V, the reference voltage is 48V, and the load demand current is set to 1A.
At the moment of converter failure, the experimental result corresponding to the conventional linear active disturbance rejection controller is shown in fig. 8(a), and it can be seen from the figure that when the converter suddenly generates open circuit failure, the output bus voltage rapidly drops from 48V to 41.6V, and it takes 28.3ms to recover to the target voltage value.
Accordingly, at the moment of the converter failure, the experimental result corresponding to the proposed controller is shown in fig. 8(b), and it can be seen from the figure that, when the converter suddenly has an open-circuit failure, the output bus voltage suddenly drops from 48V to 42.4V, and it takes 7.5ms to recover to the target voltage value.
The above verifies that the proposed controller has stronger robustness against the external disturbance at the moment of failure compared with the conventional disturbance rejection controller.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present disclosure.

Claims (5)

1. A DC converter robust self-adaptive disturbance rejection control method based on immersion and invariance theory is characterized by comprising the following steps:
the method comprises the following steps: respectively constructing state space equations of the direct current converter in a healthy state and a fault state of the switching tube;
step two: designing a cascade control structure based on a voltage outer ring and a current inner ring aiming at the direct current converter; firstly, designing a current inner ring by adopting a sliding mode control theory, and providing a closed-loop transfer function of the current inner ring of the converter by utilizing an ideal sliding mode linearization concept;
step three: aiming at the current inner loop closed-loop transfer function obtained in the step two, an extended state observer is designed by utilizing the traditional linear active disturbance rejection control theory to estimate the total disturbance inside and outside the system;
step four: aiming at the total system disturbance obtained in the step three, designing a proportional controller according to a preselected control bandwidth, and completing the design process of the whole traditional active disturbance rejection controller;
step five: on the basis of the traditional linear active disturbance rejection controller, the on-line real-time estimation of the system gain parameters is realized on the basis of immersion and invariance theories, and the design process of the proposed robust adaptive disturbance rejection control method is completed.
2. The immersion and invariance theory-based robust adaptive disturbance rejection control method for a direct current converter according to claim 1, wherein: the state space equation in the step one:
when the converter is operating in a healthy state:
Figure FDA0003437599070000011
wherein L is1，L2Input inductance values of the two-phase circuit, respectively; rL1，RL2Parasitic resistances of the two input inductors are respectively; c1，C2Respectively the output capacitance values of the two circuits; i.e. iL1，iL2The currents respectively flow through the two paths of inductors; v. ofc1，vc2The voltages at two ends of the two paths of output capacitors are respectively; l is1＝L2＝L，C1＝C2＝C，vc1＝vc2＝vc，iL1＝iL2＝iL；dHFor duty cycle definition in the healthy state, R denotes the equivalent load resistance;
when the converter is operating in a fault condition:
Figure FDA0003437599070000021
wherein d isFRepresenting the duty cycle, v, of the converter after fault reconstructiono＝vc1+vc2。
3. The immersion and invariance theory-based robust adaptive disturbance rejection control method for a direct current converter according to claim 2, wherein: the inner loop closed loop transfer function in the step two:
when the converter is operating in a healthy state:
Figure FDA0003437599070000022
wherein the content of the first and second substances,
Figure FDA0003437599070000023
Vinfor input of current, ILrefIs a reference current; when the converter is operating in a fault condition:
Figure FDA0003437599070000024
wherein the content of the first and second substances,
Figure FDA0003437599070000025
4. the immersion and invariance theory-based robust adaptive immunity control method for a direct current converter according to claim 3, wherein: the total disturbance inside and outside the system in the step three is designed as follows:
Figure FDA0003437599070000026
wherein when the converter is in a healthy state, b is equal to b1，
Figure FDA0003437599070000027
y＝vo(ii) a When the converter has b-b in fault state2，
Figure FDA0003437599070000028
y＝vc(ii) a b represents the system parameters of the converter and f represents the total disturbance of the converter system.
5. The immersion and invariance theory-based robust adaptive immunity control method for a direct current converter according to claim 4, wherein: the proportional controller in step four:
Figure FDA0003437599070000029
wherein k ispFor proportional control term gain, VrefIs the converter reference voltage.
CN202111680709.7A 2021-12-28 2021-12-28 DC converter robust self-adaptive disturbance rejection control method based on immersion and invariance theory Pending CN114421769A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116260316A (en) * 2023-05-11 2023-06-13 深圳市润海通科技有限公司 High-frequency digital direct-current power supply driving method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116260316A (en) * 2023-05-11 2023-06-13 深圳市润海通科技有限公司 High-frequency digital direct-current power supply driving method
CN116260316B (en) * 2023-05-11 2023-07-21 深圳市润海通科技有限公司 High-frequency digital direct-current power supply driving method

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