CN114552984A - Bidirectional DC/DC conversion device based on disturbance observation prediction control - Google Patents

Bidirectional DC/DC conversion device based on disturbance observation prediction control Download PDF

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CN114552984A
CN114552984A CN202111412293.0A CN202111412293A CN114552984A CN 114552984 A CN114552984 A CN 114552984A CN 202111412293 A CN202111412293 A CN 202111412293A CN 114552984 A CN114552984 A CN 114552984A
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汪凤翔
于新红
杨钰敏
吴蒙
黄东晓
夏安俊
柯栋梁
何龙
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Quanzhou Institute of Equipment Manufacturing
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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
    • H02M3/1584—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 with a plurality of power processing stages connected in parallel
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    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
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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
    • H02M3/157—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 with digital control
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
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Abstract

The invention belongs to the technical field of power electronic converter control, and discloses a bidirectional DC/DC conversion device based on disturbance observation prediction control, wherein the bidirectional DC/DC conversion method based on disturbance observation prediction control comprises the following steps: the method comprises the steps of calculating and establishing an inner-outer loop prediction control model of a converter working in a Boost mode and a Buck mode according to a mathematical model of a circuit, designing a Luenberger disturbance observer in a positive and negative direction mode, compensating the Luenberger disturbance observer to the prediction model on line, realizing model prediction control of a continuous set based on a dead-beat method by adopting error feedback and disturbance feedforward observation modes, obtaining optimal control quantity in each working mode, and sending optimal control duty ratio to a carrier phase-shifting PWM (pulse width modulation) module to obtain a switching pulse signal. The method has the advantages of high dynamic response speed of the traditional model predictive control, and can accurately and quickly track the given value under the conditions of external disturbance and internal model mismatch.

Description

Bidirectional DC/DC conversion device based on disturbance observation prediction control
Technical Field
The invention belongs to the technical field of power electronic converter control, and particularly relates to a bidirectional DC/DC conversion device based on disturbance observation prediction control.
Background
In recent years, DC-DC converters have been widely used in the fields of fuel cell automobile power systems, photovoltaic power generation, UPS, energy storage systems, and the like, by virtue of their functions of energy conversion, regulation, and the like. The alternating parallel bidirectional half-bridge type DC/DC converter is an important component of the converter, is an important bridge for connecting a direct current bus and an energy storage medium, and has the advantages of reducing the current stress and the switching loss of each phase of switching device. By adopting a topological structure in staggered parallel connection, higher frequency output can be finished, and the switching frequency of each phase is reduced. For the storage battery and the photovoltaic array battery which need low input current ripple and high dynamic response, the staggered parallel technology is a good solution.
In various control methods of the traditional staggered parallel bidirectional half-bridge DC/DC converter, the double-closed-loop PI control is the most mature, but the traditional double-closed-loop control adopts proportional-integral (PI) control, the reaction time is slow, the adjustment time is long, the parameter adjustment of a plurality of PI controllers is not easy, and the dynamic performance is greatly limited. The model predictive control is widely applied to relevant fields such as motor drive and the like with a faster dynamic response speed and a flexible control target, and if the inner ring and the outer ring adopt the control strategy of the MPC, the dynamic response speed of the system is greatly increased. However, the control performance of the MPC depends on the accuracy of system modeling, and the change of the circuit parameter will cause the mismatch between the control system parameter nominal value and the system actual parameter value, and the converter operating point is far from the nominal value, thereby affecting the stability and robustness of the control system. Due to the change of the working condition, the system is easily interfered, and parameters such as disturbance of load resistance, fluctuation of input and output voltage and parameter mismatch caused by non-idealities of inductance and capacitance can cause instability of the converter and static errors.
Therefore, a new bidirectional DC/DC conversion device based on disturbance observation prediction control is needed to overcome the defects of the prior art.
Through the above analysis, the problems and defects of the prior art are as follows:
(1) in various control methods of the traditional staggered parallel bidirectional half-bridge DC/DC converter, proportion-integral (PI) control is adopted for double closed-loop control, the reaction time is slow, the adjustment time is long, the parameter adjustment of a plurality of PI controllers is not easy, and the dynamic performance is greatly limited.
(2) The control performance of the MPC depends on the accuracy of system modeling in part, the change of circuit parameters can cause the mismatch between the control system parameter nominal value and the system actual parameter value, the working point of the converter is far away from the nominal value, and the stability and robustness of the control system are further influenced.
(3) Due to the change of working conditions, a system is easily interfered, for example, the disturbance of load resistance, the fluctuation of input and output voltage and the parameter mismatch caused by the non-ideality of inductance and capacitance can cause the instability of a converter, the output cannot accurately and quickly track reference, and static errors occur.
The difficulty in solving the above problems and defects is: the difficulty in solving the above problems is mainly reflected in how to realize the fast dynamic response, the accurate steady-state tracking and the stronger anti-interference performance of the DC/DC converter. The method can realize quick dynamic response or better disturbance rejection capability depending on the prior art, but is difficult to simultaneously consider a plurality of control targets, and does not consider the influence of a plurality of disturbance terms on steady-state static error.
The significance of solving the problems and the defects is as follows: the DC-DC converter is used as one of important components of a fuel cell automobile power system, photovoltaic power generation, a UPS, an energy storage system and the like, the performance of the DC-DC converter is particularly important for the whole system, and the stability and the reliability of the system can be directly influenced. The control system of the DC-DC converter has the advantages of the traditional model predictive control method, and the traditional method is improved to further improve the stability and the rapidity of the system, so that the control system has important application significance for improving the dynamic performance of the converter.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a bidirectional DC/DC conversion device based on disturbance observation prediction control, in particular to a bidirectional DC/DC conversion device based on disturbance observation prediction control based on online disturbance observation compensation, aiming at solving the problems that the converter is unstable and the output cannot accurately and quickly track reference due to external disturbance and internal model mismatch in the traditional model prediction control method.
The invention is realized in such a way that a bidirectional DC/DC conversion method based on disturbance observation prediction control comprises the following steps:
the method comprises the steps of calculating and establishing an inner and outer ring prediction control model of a converter working in a Boost mode and a Buck mode according to a mathematical model of a circuit, designing a Runberg disturbance observer in a positive and negative direction mode, compensating the model into the prediction model on line, adopting a mode of error feedback and disturbance feedforward observation, realizing model prediction control of a continuous set based on a dead-beat method, obtaining optimal control quantity in each working mode, and sending the optimal control duty ratio to a carrier phase-shift PWM (pulse width modulation) module CPS-PWM to obtain a switching pulse signal.
Further, the bidirectional DC/DC conversion method based on disturbance observation prediction control comprises the following steps:
determining state variables, state equations and parameters of a bidirectional half-bridge type DC/DC converter, and establishing a discrete mathematical model of the converter; the outer ring is based on a power balance principle in a current control mode, and the inner ring adopts a model prediction control method to improve the dynamic response speed of the whole control system;
respectively designing a bidirectional half-bridge DC/DC converter according to a discrete mathematical model of the system, namely a Runberg disturbance observer under a positive and negative working mode, namely a three-phase interleaved parallel Boost mode and a Buck mode;
compensating the observation state variable into a prediction model on line according to a system mathematical model and a Romberg disturbance observer, and respectively adjusting the optimal control quantity output by the converter under a positive and negative working mode by adopting an error feedback and observation disturbance feedforward control mode and combining with continuous set model prediction control based on a dead beat method;
and step four, sending the optimal control quantity duty ratio into a CPS-PWM module to obtain a pulse signal of the three-phase switching tube.
Further, in the first step, the state variables, the state equations and the parameters of the bidirectional half-bridge type DC/DC converter are determined, and a discrete mathematical model of the converter is established; the outer ring is based on a power balance principle in a current control mode, and the inner ring adopts a model prediction control method to improve the dynamic response speed of the whole control system, and the method comprises the following steps:
(1) establishing a converter mathematical model: when the converter works in a Boost mode, modeling is carried out according to the on and off of a switch, and a three-phase interleaved Boost converter continuous time mathematical model is obtained based on kirchhoff's law and a state space average method:
Figure RE-GDA0003610175740000041
wherein u isi(t) is the system input, Vin、VoInput and output voltages, R, respectivelyoIs an equivalent load resistance, CfTo output capacitance, Li(i is 1,2,3) is inductance of each phase, i isLi(i-1, 2,3) is the inductance current of each phase, RLiAnd (i is 1,2 and 3) is equivalent series resistance of each phase of inductor.
Adopting forward Euler discretization to obtain a discrete time mathematical model of the converter:
Figure RE-GDA0003610175740000042
wherein, TsFor the sampling time, V ═ VinAnd A, B, C and E are system coefficient matrixes:
Figure RE-GDA0003610175740000043
Figure RE-GDA0003610175740000044
x＝[iL1 iL2 iL3 Vo]T。
the outer loop is based on the power balance principle: obtaining the relation between input and output and a total inductive current reference value according to a model instantaneous power balance theory:
Figure RE-GDA0003610175740000045
and 1/3, requiring the reference value of each phase current to be the total reference value to realize current equalization, and obtaining the reference value of each phase inductance current as follows:
Figure RE-GDA0003610175740000046
the inner loop adopts a model prediction control method: assuming that the input and output voltages are kept constant in a sampling period, the inductance current changes linearly, and according to a discrete mathematical model, the inductance current value at the k +1 moment is obtained by predicting from the k moment:
Figure RE-GDA0003610175740000051
the predictive control cost function yields:
Figure RE-GDA0003610175740000052
respectively couple the cost function to the control quantity ui(k) Partial derivatives are determined and the control quantity when the cost function is minimized is determined by making the derivative equal to 0Taking values:
computing
Figure RE-GDA0003610175740000053
Obtaining:
Figure RE-GDA0003610175740000054
and the control quantity is output to a CPS-PWM module for modulation.
(2) When the converter works in a Buck mode, modeling is carried out according to the on and off of a switch, and a three-phase staggered parallel Buck converter continuous time mathematical model is obtained based on kirchhoff's law and a state space average method:
Figure RE-GDA0003610175740000055
obtaining a discrete time mathematical model of the converter:
Figure RE-GDA0003610175740000056
wherein, TsTo sample time, Ab,BbAnd C is a system coefficient matrix:
Figure RE-GDA0003610175740000057
Figure RE-GDA0003610175740000058
x＝[iL1 iL2 iL3 Vo]T。
according to kirchhoff current theory:
Figure RE-GDA0003610175740000061
considering current sharing, the reference value of the inductance current of each phase is as follows:
Figure RE-GDA0003610175740000062
the inner ring adopts a model prediction control method, and the inductance current value at the k +1 moment is obtained by predicting the k moment:
Figure RE-GDA0003610175740000063
the cost function yields:
Figure RE-GDA0003610175740000064
computing
Figure RE-GDA0003610175740000065
Obtaining:
Figure RE-GDA0003610175740000066
and the control quantity is output to a CPS-PWM module for modulation.
Further, in the second step, designing the bidirectional half-bridge type DC/DC converter respectively according to the discrete mathematical model of the system under the positive and negative working modes, i.e. the three-phase interleaved parallel Boost and Buck modes, the lunberg disturbance observer includes:
and designing a Luenberger disturbance observer, and compensating the observed state variable into the prediction model on line.
(1) For Boost mode of operation:
lumped disturbance observation: according to the discrete mathematical model of the first step, the lumped disturbance term is defined as:
Figure RE-GDA0003610175740000067
taking the disturbance term and the inductive current as state variables, and rewriting a discrete mathematical model of the system into:
Figure RE-GDA0003610175740000068
wherein,Xdi(t)＝[iLi Di]T，Cd＝[1 0]，
Figure RE-GDA0003610175740000069
vd＝Vo。
the disturbance observer is then designed to:
Figure RE-GDA0003610175740000071
wherein H ═ H1 H2]TIn order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000072
is the observed value of the lumped disturbance term and the inductive current.
Defining the error between the state variable and the observed value at the moment k +1 as:
Figure RE-GDA0003610175740000073
to ensure the stability of the observer, an appropriate feedback gain value is selected such that (A)d-HCd) Matrix stabilization, i.e. the closed loop pole is located in the left half-open plane of the complex plane, i.e. the observation error is made
Figure RE-GDA00036101757400000711
Approaching zero over time, i.e. the observed values tend towards the actual values, matrix (A)d-HCd) Characteristic value p of1、p2Must satisfy p1,p2Is less than 0. Thus, the observation error gradually decreases with time, the state variable DiUsing the observed values separately
Figure RE-GDA00036101757400000712
Instead.
And (3) observing the equivalent resistance of the load, taking the output voltage and the output current as state variables, and writing a discrete mathematical model as follows:
Figure RE-GDA0003610175740000074
wherein,
Figure RE-GDA0003610175740000075
Co＝[1 0]，
Figure RE-GDA0003610175740000076
Figure RE-GDA0003610175740000077
IL＝[iL1 iL2 iL3]T。
the disturbance observer is then designed to:
Figure RE-GDA0003610175740000078
wherein L ═ L1 L2]TIn order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000079
are observed values of the output voltage and the output current.
Defining the error between the state variable and the observed value at the moment k +1 as:
Figure RE-GDA00036101757400000710
selecting a suitable feedback gain L1And L2Make (A)o-LCo) Stabilization, replacing the actual value with the observed value of the load equivalent resistance
Figure RE-GDA0003610175740000081
(2) For the Buck mode of operation:
and (3) outer ring disturbance observation: according to the discrete mathematical model of the first step, the item to be observed is defined as:
Figure RE-GDA0003610175740000082
the discrete mathematical model is written as follows, with the disturbance term and the output voltage defined as state variables:
Figure RE-GDA0003610175740000083
the disturbance observer is then designed to:
Figure RE-GDA0003610175740000084
wherein, F1、F2In order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000085
the observed values of the output voltage and the outer ring disturbance term are obtained; selecting a suitable feedback gain F1、F2The actual value is replaced by the observed disturbance term.
And (3) inner ring disturbance observation, according to the discrete mathematical model of the step one, defining the item to be observed as:
Figure RE-GDA0003610175740000086
taking the disturbance term and the inductive current as state variables, the discrete mathematical model of the system is rewritten as:
Figure RE-GDA0003610175740000087
the disturbance observer is then designed to:
Figure RE-GDA0003610175740000088
wherein G is1、G2In order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000089
the observed values of the inductive current and the inner ring disturbance term are obtained; selecting a suitable feedback gain G1、G2The actual value is replaced by the observed disturbance term.
Further, in the third step, the online compensation of the observation state variable to the prediction model according to the system mathematical model and the lunberg disturbance observer, and the adjustment of the optimal control quantity output by the converter in the positive and negative direction working mode by adopting the error feedback and observation disturbance feedforward control mode in combination with the continuous set model prediction control based on the dead beat method, respectively, include:
compensating the observed state variables into the prediction model on line:
(1) in a Boost operating mode:
reference value of outer ring output current:
Figure RE-GDA0003610175740000091
inner loop output control quantity:
Figure RE-GDA0003610175740000092
(2) in the Buck mode of operation:
outer loop output current reference value:
Figure RE-GDA0003610175740000093
inner loop output control quantity:
Figure RE-GDA0003610175740000094
further, in the fourth step, the sending the optimal control quantity duty ratio to the CPS-PWM module to obtain the pulse signal of the three-phase switching tube includes:
the duty ratio u of the optimal control quantity1、u2、u3Sending the signals into a modulation module to obtain pulse signals of the three-phase switching tube; the modulation mode adopts CPS-PWM mode, each phase duty ratio output modulates 3 triangular carriers, the amplitude of the triangular carrier frequency of each phase is equal, and the phase is delayed in sequence
Figure RE-GDA0003610175740000095
Each carrier cycle, thereby delaying the on-time of each phase switch by 120 ° in turn.
The invention aims to provide a bidirectional DC/DC conversion device based on disturbance observation prediction control, which applies the bidirectional DC/DC conversion method based on disturbance observation prediction control, and comprises the following components:
the discrete mathematical model building module is used for determining state variables, state equations and parameters of the bidirectional half-bridge DC/DC converter and building a discrete mathematical model of the converter;
the dynamic response speed control module is used for improving the dynamic response speed of the whole control system by the inner ring by adopting a model prediction control method on the basis of a power balance principle in the outer ring in the current control mode;
the working mode design module is used for respectively designing the bidirectional half-bridge DC/DC converter to be used as a Luenberger disturbance observer under a positive and negative working mode, namely a three-phase interleaved parallel Boost mode and a Buck mode according to a system discrete mathematical model;
the optimal control quantity adjusting module is used for compensating the observation state variable into the prediction model on line according to a system mathematical model and a Romberg disturbance observer, and respectively adjusting the optimal control quantity output by the converter under a positive and negative direction working mode by adopting an error feedback and observation disturbance feedforward control mode and combining with continuous set model prediction control based on a dead beat method;
and the pulse signal acquisition module is used for sending the optimal control quantity duty ratio to the CPS-PWM module to acquire a pulse signal of the three-phase switching tube.
It is a further object of the invention to provide a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of:
the method comprises the steps of calculating and establishing an inner and outer ring prediction control model of a converter working in a Boost mode and a Buck mode according to a mathematical model of a circuit, designing a Runberg disturbance observer in a positive and negative direction mode, compensating the model into the prediction model on line, adopting a mode of error feedback and disturbance feedforward observation, realizing model prediction control of a continuous set based on a dead-beat method, obtaining optimal control quantity in each working mode, and sending the optimal control duty ratio to a carrier phase-shift PWM (pulse width modulation) module CPS-PWM to obtain a switching pulse signal.
It is a further object of the present invention to provide a computer readable storage medium storing a computer program which, when executed by a processor, causes the processor to execute the bidirectional DC/DC conversion method based on disturbance observation prediction control.
Another object of the present invention is to provide an information data processing terminal for realizing the function of the bidirectional DC/DC conversion device based on disturbance observation prediction control.
By combining all the technical schemes, the invention has the advantages and positive effects that: the bidirectional DC/DC conversion method based on disturbance observation prediction control provided by the invention is based on a model prediction control strategy, realizes CPS-PWM-based dead-beat prediction control, is combined with a Luenberg disturbance observer to realize a control strategy suitable for a three-phase interleaved parallel bidirectional half-bridge type DC/DC converter, can meet the requirements that the interleaved parallel bidirectional DC/DC converter can still accurately and quickly track load voltage reference under the working conditions of load disturbance, input voltage disturbance and inductive resistance, and solves the problems that the converter is unstable and the output cannot accurately and quickly track the reference due to external disturbance and internal model mismatch in the traditional model prediction control method.
The invention provides a model prediction control method of a three-phase interleaved parallel bidirectional half-bridge DC-DC converter combined with a Luenberger disturbance observer. The method has the advantages of high dynamic response speed of traditional model predictive control, can accurately and quickly track the given value under the condition of external disturbance and internal model mismatch, and has high anti-interference capability.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of a bidirectional DC/DC conversion method based on disturbance observation prediction control according to an embodiment of the present invention.
FIG. 2 is a block diagram of a bidirectional DC/DC converter based on disturbance observation prediction control according to an embodiment of the present invention;
in the figure: 1. a discrete mathematical model construction module; 2. a dynamic response speed control module; 3. a working mode design module; 4. an optimal control quantity adjusting module; 5. and a pulse signal acquisition module.
Fig. 3 is an overall control block diagram of a bidirectional DC/DC conversion device based on disturbance observation prediction control according to an embodiment of the present invention.
Fig. 3(a) is a schematic diagram of a Boost operating mode according to an embodiment of the present invention.
Fig. 3(b) is a schematic diagram of the Buck operating mode according to the embodiment of the present invention.
Fig. 4 is a circuit topology diagram of a three-phase interleaved parallel bidirectional half-bridge DC-DC converter according to an embodiment of the present invention.
Fig. 5 is a waveform diagram of a carrier phase-shift pulse width modulation method according to an embodiment of the present invention.
Fig. 6 is a waveform diagram of a simulation result of the control method provided by the embodiment of the present invention in the Boost operating mode under the conditions of system disturbance and model mismatch.
Fig. 6(a) is a simulated waveform diagram of output voltage reference step according to the embodiment of the present invention.
Fig. 6(b) is a waveform diagram of an input voltage step disturbance simulation provided by an embodiment of the present invention.
Fig. 6(c) is a simulated waveform diagram of load step disturbance according to an embodiment of the present invention.
Fig. 6(d) is a waveform diagram of an inductance mismatch simulation provided by the embodiment of the present invention.
Fig. 7 is a waveform diagram of a simulation result of the control method provided by the embodiment of the present invention in the Buck operating mode under the conditions that the system is disturbed and the model is mismatched.
Fig. 7(a) is a simulated waveform diagram of output voltage reference step according to an embodiment of the present invention.
Fig. 7(b) is a simulated waveform diagram of load step disturbance provided by the embodiment of the present invention.
Fig. 7(c) is a waveform diagram of an inductance mismatch simulation provided by the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. 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 view of the problems in the prior art, the present invention provides a bidirectional DC/DC conversion apparatus based on disturbance observation prediction control, and the following describes the present invention in detail with reference to the accompanying drawings.
As shown in fig. 1, a bidirectional DC/DC conversion method based on disturbance observation prediction control according to an embodiment of the present invention includes the following steps:
s101, determining state variables, state equations and parameters of the bidirectional half-bridge DC/DC converter, and establishing a discrete mathematical model of the converter;
s102, an outer ring in a current control mode is based on a power balance principle, and an inner ring adopts a model prediction control method to improve the dynamic response speed of the whole control system;
s103, respectively designing a Luenberger disturbance observer of the bidirectional half-bridge type DC/DC converter in a positive and negative working mode, namely a three-phase interleaved parallel Boost mode and a Buck mode according to a system discrete mathematical model;
s104, compensating the observation state variable into a prediction model on line according to a system mathematical model and a Romberg disturbance observer, and respectively adjusting the optimal control quantity output by the converter under a positive and negative working mode by adopting an error feedback and observation disturbance feedforward control mode and combining with continuous set model prediction control based on a dead beat method;
and S105, sending the optimal control quantity duty ratio to a CPS-PWM module to obtain a pulse signal of the three-phase switching tube.
As shown in fig. 2, the bidirectional DC/DC conversion apparatus based on disturbance observation prediction control according to the embodiment of the present invention includes:
the discrete mathematical model building module 1 is used for determining state variables, state equations and parameters of the bidirectional half-bridge DC/DC converter and building a discrete mathematical model of the converter;
the dynamic response speed control module 2 is used for improving the dynamic response speed of the whole control system by the inner ring by adopting a model prediction control method on the basis of the power balance principle of the outer ring in the current control mode;
the working mode design module 3 is used for respectively designing the bidirectional half-bridge type DC/DC converter to be a Luenberger disturbance observer under a positive and negative working mode, namely a three-phase interleaved parallel Boost mode and a Buck mode according to a system discrete mathematical model;
the optimal control quantity adjusting module 4 is used for compensating the observation state variable into the prediction model on line according to a system mathematical model and a Romberg disturbance observer, and respectively adjusting the optimal control quantity output by the converter under a positive and negative direction working mode by adopting an error feedback and observation disturbance feedforward control mode and combining with continuous set model prediction control based on a dead beat method;
and the pulse signal acquisition module 5 is used for sending the optimal control quantity duty ratio to the CPS-PWM module to acquire a pulse signal of the three-phase switching tube.
FIG. 3 is a block diagram of the overall control of the converter control system of the present invention;
FIG. 4 is a circuit topology diagram of a three-phase interleaved parallel bidirectional half-bridge type DC-DC converter employed in the present invention;
FIG. 5 is a waveform diagram (CPS-PWM, D is duty ratio) of the carrier phase shift pulse width modulation method employed in the present invention;
fig. 6(a) to 6(d) are waveforms of simulation results of the control mode proposed by the present invention under the Boost operating mode under the conditions of system disturbance and model mismatch, respectively;
fig. 7(a) -fig. 7(c) are waveforms of simulation results of the control mode proposed by the present invention under the condition that the system is disturbed and the model is mismatched in the Buck operating mode, respectively.
The technical solution of the present invention is further described below with reference to specific examples.
1. Summary of the invention
The invention discloses a model prediction control method of a three-phase interleaved parallel bidirectional half-bridge DC/DC converter based on disturbance observation, which comprises the following steps: the method comprises the steps of calculating and establishing an inner and outer ring prediction control model of a converter working in a Boost mode and a Buck mode according to a mathematical model of a circuit, designing a Runberg disturbance observer in a positive and negative direction mode, compensating the model into the prediction model on line, realizing model prediction control of a continuous set based on a dead-beat method by adopting an error feedback and observation disturbance feedforward mode, obtaining optimal control quantity in each working mode, and sending the optimal control duty ratio to a carrier phase shift PWM (CPS-PWM) module to obtain a switching pulse signal. The invention can meet the requirement that the staggered parallel bidirectional DC/DC converter can still accurately and quickly track the load voltage reference under the working conditions of load disturbance, input voltage disturbance and existence of inductive resistance.
2. Summary of the invention
The invention aims to provide a control strategy which is based on a model prediction control strategy, realizes CPS-PWM-based dead-beat prediction control, is combined with a Luenberger disturbance observer to realize the control strategy suitable for a three-phase interleaved parallel bidirectional half-bridge DC/DC converter, and solves the problems that the converter is unstable and the output cannot accurately and quickly track the reference due to external disturbance and internal model mismatch in the traditional model prediction control method.
The technical scheme adopted by the invention is implemented according to the following steps:
step 1, determining state variables, state equations and parameters of the bidirectional half-bridge type DC/DC converter, and establishing a discrete mathematical model of the converter. The outer ring is based on a power balance principle in a current control mode, and the inner ring adopts a model prediction control method to improve the dynamic response speed of the whole control system;
step 2, respectively designing a bidirectional half-bridge type DC/DC converter according to a system discrete mathematical model, namely a Runberg disturbance observer under a positive and negative working mode, namely a three-phase interleaved parallel Boost mode and a Buck mode;
step 3, compensating the observation state variable into a prediction model on line according to a system mathematical model and a Romberg disturbance observer, and respectively adjusting the optimal control quantity output by the converter under a positive and negative working mode by adopting an error feedback and observation disturbance feedforward control mode and combining with continuous set model prediction control based on a dead beat method;
and 4, sending the optimal control quantity duty ratio into a CPS-PWM module to obtain a pulse signal of the three-phase switching tube.
The invention can meet the requirement that the staggered parallel bidirectional DC/DC converter can still accurately and quickly track the load voltage reference under the working conditions of load disturbance, input voltage disturbance and existence of inductive resistance.
Step 1 specifically includes:
establishing a converter mathematical model:
when the converter works in a Boost mode, modeling is carried out according to the on and off of a switch, and a three-phase interleaved Boost converter continuous time mathematical model can be obtained based on kirchhoff's law and a state space average method:
Figure RE-GDA0003610175740000151
wherein u isi(t) is the system input, Vin、VoInput and output voltages, R, respectivelyoIs an equivalent load resistance, CfTo output capacitance, Li(i is 1,2,3) is inductance of each phase,iLi(i-1, 2,3) is the inductance current of each phase, RLiAnd (i is 1,2 and 3) is equivalent series resistance of each phase of inductor. Further adopting forward Euler discretization, a discrete time mathematical model of the converter can be obtained:
Figure RE-GDA0003610175740000152
wherein, TsFor the sampling time, V ═ VinAnd A, B, C and E are system coefficient matrixes:
Figure RE-GDA0003610175740000161
Figure RE-GDA0003610175740000162
x＝[iL1 iL2 iL3 Vo]。
the outer loop is based on the power balance principle: obtaining the relation between the input and the output and the total inductive current reference value according to the model instantaneous power balance theory:
Figure RE-GDA0003610175740000163
1/3, requiring each phase current reference value as a total reference value to realize current equalization, and obtaining each phase inductance current reference value as follows:
Figure RE-GDA0003610175740000164
the inner loop adopts a model prediction control method: assuming that the input and output voltages are kept constant in a sampling period, the inductance current changes linearly, and according to a discrete mathematical model, the inductance current value at the k +1 moment can be predicted from the k moment:
Figure RE-GDA0003610175740000165
the predictive control cost function may result in:
Figure RE-GDA0003610175740000166
respectively applying the cost function to the control quantity ui(k) And (3) solving the partial derivative, and determining the control quantity value when the cost function is minimum by enabling the derivative to be equal to 0:
computing
Figure RE-GDA0003610175740000167
Obtaining:
Figure RE-GDA0003610175740000168
and the control quantity is output to a CPS-PWM module for modulation.
When the converter works in a Buck mode, modeling is carried out according to the on and off of a switch, and a three-phase staggered parallel Buck converter continuous time mathematical model can be obtained based on kirchhoff's law and a state space average method:
Figure RE-GDA0003610175740000171
similarly, a discrete-time mathematical model of the converter can be obtained:
Figure RE-GDA0003610175740000172
wherein, TsFor sampling time, A, B, C are the system coefficient matrix:
Figure RE-GDA0003610175740000173
Figure RE-GDA0003610175740000174
x＝[iL1 iL2 iL3 Vo]。
in the same way as above, according to kirchhoff current theory:
Figure RE-GDA0003610175740000175
considering current sharing, the reference value of the inductance current of each phase is as follows:
Figure RE-GDA0003610175740000176
the inner ring is similar to the inner ring, and the inductance current value at the k +1 moment can be obtained by predicting the k moment by adopting a model prediction control method:
Figure RE-GDA0003610175740000177
the cost function can be derived as:
Figure RE-GDA0003610175740000178
computing
Figure RE-GDA0003610175740000179
Obtaining:
Figure RE-GDA00036101757400001710
and the control quantity is output to a CPS-PWM module for modulation.
Secondly, the step 2 specifically includes:
and designing a Luenberger disturbance observer, and compensating the observed state variable into the prediction model on line.
For Boost mode of operation:
lumped disturbance observation: according to the discrete mathematical model of step 1, the lumped disturbance term is defined as:
Figure RE-GDA0003610175740000181
taking the disturbance term and the inductor current as state variables, the discrete mathematical model of the system can be rewritten as follows:
Figure RE-GDA0003610175740000182
wherein Xdi(t)＝[iLi Di]T，Cd＝[1 0]，
Figure RE-GDA0003610175740000183
Figure RE-GDA0003610175740000184
vd＝Vo. The disturbance observer can be designed as follows:
Figure RE-GDA0003610175740000185
wherein H ═ H1 H2]TIn order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000186
is the observed value of the lumped disturbance term and the inductive current.
According to the above equation, the error between the state variable and the observed value at the time k +1 is defined as:
Figure RE-GDA0003610175740000187
to ensure the stability of the observer, an appropriate feedback gain value is selected such that (A)d-HCd) The observation error can be caused by matrix stabilization, namely the closed loop pole is positioned in the left half-open plane of the complex plane
Figure RE-GDA0003610175740000188
Approaching zero over time, i.e. the observed value tends towards the actual value. This means that the matrix (A)d-HCd) Characteristic value p of1、p2Must satisfy p1,p2Is less than 0. Therefore, the observation error gradually decreases with time. State variable DiCan use the observed values respectively
Figure RE-GDA00036101757400001812
Instead.
And (3) observing load equivalent resistance, taking the output voltage and the output current as state variables, and writing a discrete mathematical model as follows:
Figure RE-GDA0003610175740000189
wherein
Figure RE-GDA00036101757400001810
Co＝[1 0]，
Figure RE-GDA00036101757400001811
Figure RE-GDA0003610175740000191
IL＝[iL1 iL2 iL3]T。
The disturbance observer can be designed to:
Figure RE-GDA0003610175740000192
wherein L ═ L1 L2]TIn order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000193
are observed values of the output voltage and the output current.
Similarly, the error between the state variable and the observed value at the time k +1 is defined as:
Figure RE-GDA0003610175740000194
selecting a suitable feedback gain L1And L2Make (A)o-LCo) And (3) stabilizing, wherein the load equivalent resistance can replace an actual value with an observed value, and is as follows:
Figure RE-GDA0003610175740000195
similarly, for the Buck mode of operation:
and (3) outer ring disturbance observation: according to the discrete mathematical model of step 1, the item to be observed is defined as:
Figure RE-GDA0003610175740000196
writing a discrete mathematical model by taking a defined disturbance term and an output voltage as state variables as follows:
Figure RE-GDA0003610175740000197
the disturbance observer can be designed to:
Figure RE-GDA0003610175740000198
wherein F1、F2In order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000199
selecting proper feedback gain F for observed values of the output voltage and the outer loop disturbance term1、F2The observed perturbation term may be substituted for the actual value.
And (3) inner ring disturbance observation, according to the discrete mathematical model in the step 1, defining the item to be observed as:
Figure RE-GDA00036101757400001910
taking the disturbance term and the inductor current as state variables, the discrete mathematical model of the system can be rewritten as follows:
Figure RE-GDA0003610175740000201
the disturbance observer can be designed as follows:
Figure RE-GDA0003610175740000202
wherein G is1、G2In order to be the feedback gain of the observer,
Figure RE-GDA0003610175740000203
selecting proper feedback gain G for the observed values of the inductive current and the inner loop disturbance term1、G2The observed perturbation term may be substituted for the actual value.
Step 3 further specifically includes:
compensating the observed state variables into the prediction model on line:
in a Boost operating mode:
reference value of outer ring output current:
Figure RE-GDA0003610175740000204
inner loop output control quantity:
Figure RE-GDA0003610175740000205
in the Buck mode of operation:
reference value of outer ring output current:
Figure RE-GDA0003610175740000206
inner loop output control quantity:
Figure RE-GDA0003610175740000207
fourthly, further, the step 4 specifically includes:
the duty ratio u of the optimal control quantity1、u2、u3And sending the signal into a modulation module to obtain a pulse signal of the three-phase switching tube. The modulation mode adopts CPS-PWM mode, the amplitude of the triangular carrier frequency of each phase is equal, and the phase is delayed in turn
Figure RE-GDA0003610175740000208
Each phase duty cycle output modulates 3 triangular carriers, thereby sequentially delaying the on-time of each phase switch by 120 °.
From the above, the invention provides a model prediction control method of a three-phase interleaved parallel bidirectional half-bridge DC-DC converter combined with a Luenberger disturbance observer. The method has the advantages of high dynamic response speed of traditional model predictive control, can accurately and quickly track the given value under the condition of external disturbance and internal model mismatch, and has high anti-interference capability.
In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the above embodiments, all or part of the implementation may be realized by software, hardware, firmware, or any combination thereof. When used in whole or in part, can be implemented in a computer program product that includes one or more computer instructions. When loaded or executed on a computer, cause the flow or functions according to embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL), or wireless (e.g., infrared, wireless, microwave, etc.)). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.
The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A bidirectional DC/DC conversion device based on disturbance observation prediction control is characterized in that the bidirectional DC/DC conversion method based on disturbance observation prediction control comprises the following steps:
the method comprises the steps of calculating and establishing an inner and outer ring prediction control model of a converter working in a Boost mode and a Buck mode according to a mathematical model of a circuit, compensating a Runberg disturbance observer in a forward and reverse direction mode into the prediction model on line, realizing model prediction control of a continuous set based on a dead-beat method by adopting an error feedback and observation disturbance feedforward mode, obtaining optimal control quantity in each working mode, and sending the optimal control duty ratio into a carrier phase shift PWM (pulse width modulation) module CPS-PWM (control performance-pulse width modulation) to obtain a switching pulse signal.
2. The bidirectional DC/DC conversion method based on disturbance observation prediction control according to claim 1, wherein the bidirectional DC/DC conversion method based on disturbance observation prediction control comprises the steps of:
determining state variables, state equations and parameters of a bidirectional half-bridge DC/DC converter, and establishing a discrete mathematical model of the converter; the outer ring is based on a power balance principle in a current control mode, and the inner ring adopts a model prediction control method to improve the dynamic response speed of the whole control system;
respectively designing a Luenberger disturbance observer of the bidirectional half-bridge type DC/DC converter in a positive and negative working mode, namely a three-phase interleaved parallel Boost mode and a Buck mode according to a system discrete mathematical model;
compensating the observation state variable into a prediction model on line according to a system mathematical model and a Romberg disturbance observer, and respectively adjusting the optimal control quantity output by the converter under a positive and negative working mode by adopting an error feedback and observation disturbance feedforward control mode and combining with continuous set model prediction control based on a dead beat method;
and step four, sending the optimal control quantity duty ratio into a CPS-PWM module to obtain a pulse signal of the three-phase switching tube.
3. The bidirectional DC/DC conversion method based on disturbance observation prediction control as claimed in claim 2, wherein in step one, the state variables, the state equations and the parameters of the bidirectional half-bridge type DC/DC converter are determined, and a discrete mathematical model of the converter is established; the outer ring is based on a power balance principle in a current control mode, and the inner ring adopts a model prediction control method to improve the dynamic response speed of the whole control system, and the method comprises the following steps:
(1) establishing a converter mathematical model: when the converter works in a Boost mode, modeling is carried out according to the on and off of a switch, and a three-phase interleaved Boost converter continuous time mathematical model is obtained based on kirchhoff's law and a state space average method:
Figure RE-FDA0003535959820000021
wherein u isi(t) is the system input, Vin、VoInput and output voltages, R, respectivelyoIs an equivalent load resistance, CfTo output capacitance, Li(i is 1,2,3) is inductance of each phase, i isLi(i-1, 2,3) is the inductance current of each phase, RLi(i is 1,2,3) is equivalent series resistance of each phase of inductor;
adopting forward Euler discretization to obtain a discrete time mathematical model of the converter:
Figure RE-FDA0003535959820000022
wherein, TsFor the sampling time, V ═ VinAnd A, B, C and E are system coefficient matrixes:
Figure RE-FDA0003535959820000023
Figure RE-FDA0003535959820000024
x＝[iL1 iL2 iL3 Vo]；
the outer loop is based on the power balance principle: obtaining the relation between the input and the output and the total inductive current reference value according to the model instantaneous power balance theory:
Figure RE-FDA0003535959820000025
and 1/3, requiring the reference value of each phase current to be the total reference value to realize current equalization, and obtaining the reference value of each phase inductance current as follows:
Figure RE-FDA0003535959820000026
the inner loop adopts a model prediction control method: assuming that the input and output voltages are kept constant in a sampling period, the inductance current changes linearly, and according to a discrete mathematical model, the inductance current value at the k +1 moment is obtained by predicting from the k moment:
Figure RE-FDA0003535959820000031
predicting control costsThe function yields:
Figure RE-FDA0003535959820000032
respectively applying the cost function to the control quantity ui(k) And (3) solving a partial derivative, and enabling the derivative to be equal to 0 to determine a control quantity value when the cost function is minimum:
computing
Figure RE-FDA0003535959820000033
Obtaining:
Figure RE-FDA0003535959820000034
the control quantity is output to a CPS-PWM module for modulation;
(2) when the converter works in a Buck mode, modeling is carried out according to the on and off of a switch, and a three-phase staggered parallel Buck converter continuous time mathematical model is obtained based on kirchhoff's law and a state space average method:
Figure RE-FDA0003535959820000035
obtaining a discrete time mathematical model of the converter:
Figure RE-FDA0003535959820000036
wherein, TsTo sample time, Ab,BbAnd C is a system coefficient matrix:
Figure RE-FDA0003535959820000037
Figure RE-FDA0003535959820000041
x＝[iL1 iL2 iL3 Vo]；
according to kirchhoffThe current theory is as follows:
Figure RE-FDA0003535959820000042
considering the current sharing, the reference value of the inductance current of each phase is:
Figure RE-FDA0003535959820000043
the inner ring adopts a model prediction control method, and the inductance current value at the k +1 moment is obtained by predicting the k moment:
Figure RE-FDA0003535959820000044
the cost function yields:
Figure RE-FDA0003535959820000045
computing
Figure RE-FDA0003535959820000046
Obtaining:
Figure RE-FDA0003535959820000047
and the control quantity is output to a CPS-PWM module for modulation.
4. The bidirectional DC/DC conversion method based on disturbance observation prediction control as claimed in claim 2, wherein in step two, the bidirectional half-bridge type DC/DC converter is respectively designed according to the discrete mathematical model of the system under the forward and reverse working mode, namely the Luenberger disturbance observer under the three-phase interleaved parallel Boost and Buck mode, and the method comprises the following steps:
designing a Luenberger disturbance observer, and compensating an observed state variable into a prediction model on line;
(1) for Boost mode of operation:
lumped disturbance observation: according to the discrete mathematical model of the first step, the lumped disturbance term is defined as:
Figure RE-FDA0003535959820000048
taking the disturbance term and the inductive current as state variables, and rewriting a discrete mathematical model of the system into:
Figure RE-FDA0003535959820000049
wherein Xdi(t)＝[iLi Di]T，Cd＝[1 0]，
Figure RE-FDA0003535959820000051
vd＝Vo；
The disturbance observer is then designed to:
Figure RE-FDA0003535959820000052
wherein H ═ H1 H2]TIn order to be the feedback gain of the observer,
Figure RE-FDA0003535959820000053
the observed values of the lumped disturbance term and the inductive current are obtained;
defining the error between the state variable and the observed value at the moment k +1 as:
Figure RE-FDA0003535959820000054
to ensure the stability of the observer, an appropriate feedback gain value is selected such that (A)d-HCd) Matrix stabilisation, i.e. the poles of the closed loop lie within the left-half plane of the complex plane, i.e.Can make the observation error
Figure RE-FDA0003535959820000055
Approaching zero over time, i.e. the observed values tend towards the actual values, matrix (A)d-HCd) Characteristic value p of1、p2Must satisfy p1,p2Less than 0; thus, the observation error gradually decreases with time, the state variable DiUsing the observed values separately
Figure RE-FDA0003535959820000056
Replacing;
and (3) observing the equivalent resistance of the load, taking the output voltage and the output current as state variables, and writing a discrete mathematical model as follows:
Figure RE-FDA0003535959820000057
wherein,
Figure RE-FDA0003535959820000058
Co＝[1 0]，
Figure RE-FDA0003535959820000059
Figure RE-FDA00035359598200000510
IL＝[iL1 iL2 iL3]T；
the disturbance observer is then designed to:
Figure RE-FDA00035359598200000511
wherein L ═ L1 L2]TIn order to be the feedback gain of the observer,
Figure RE-FDA0003535959820000061
is an observed value of the output voltage and the output current;
defining the error between the state variable and the observed value at the moment k +1 as:
Figure RE-FDA0003535959820000062
selecting a suitable feedback gain L1And L2Make (A)o-LCo) Stabilization, replacing the actual value with the observed value of the load equivalent resistance
Figure RE-FDA0003535959820000063
(2) For the Buck mode of operation:
and (3) outer ring disturbance observation: according to the discrete mathematical model of the first step, the item to be observed is defined as:
Figure RE-FDA0003535959820000064
the discrete mathematical model is written as follows, with the disturbance term and the output voltage defined as state variables:
Figure RE-FDA0003535959820000065
the disturbance observer is then designed to:
Figure RE-FDA0003535959820000066
wherein, F1、F2In order to be the feedback gain of the observer,
Figure RE-FDA0003535959820000067
the observed values of the output voltage and the outer ring disturbance term are obtained; selecting proper onesFeedback gain F of1、F2Replacing the actual value with the observation disturbance term;
and (3) inner ring disturbance observation, according to the discrete mathematical model of the step one, defining the item to be observed as:
Figure RE-FDA0003535959820000068
taking the disturbance term and the inductive current as state variables, the discrete mathematical model of the system is rewritten as:
Figure RE-FDA0003535959820000069
the disturbance observer is then designed to:
Figure RE-FDA0003535959820000071
wherein G is1、G2In order to be the feedback gain of the observer,
Figure RE-FDA0003535959820000072
the observed values of the inductive current and the inner ring disturbance term are obtained; selecting a suitable feedback gain G1、G2The actual value is replaced by the observed disturbance term.
5. The bidirectional DC/DC conversion method based on disturbance observation prediction control as claimed in claim 2, wherein in step three, the on-line compensation of the observation state variable to the prediction model according to the system mathematical model and the Luenberger disturbance observer, and the adjustment of the optimal control quantity output by the converter in the positive and negative direction working mode by adopting the error feedback and observation disturbance feedforward control modes in combination with the continuum model prediction control based on the dead beat method, respectively, comprises:
compensating the observed state variables into the prediction model on line:
(1) in a Boost operating mode:
outer loop output current reference value:
Figure RE-FDA0003535959820000073
inner loop output control quantity:
Figure RE-FDA0003535959820000074
(2) in the Buck mode of operation:
reference value of outer ring output current:
Figure RE-FDA0003535959820000075
inner loop output control quantity:
Figure RE-FDA0003535959820000076
6. the bidirectional DC/DC conversion method based on disturbance observation prediction control as claimed in claim 2, wherein in step four, said sending the optimal control quantity duty ratio to the CPS-PWM module to obtain the pulse signal of the three-phase switching tube comprises:
the duty ratio u of the optimal control quantity1、u2、u3Sending the signals into a modulation module to obtain pulse signals of the three-phase switching tube; the modulation mode adopts CPS-PWM mode, the triangular carrier frequency amplitude of each phase is equal, and the phase is delayed in turn
Figure RE-FDA0003535959820000077
Each phase duty cycle output modulates 3 triangular carriers, thereby sequentially delaying the on-time of each phase switch by 120 °.
7. A bidirectional DC/DC conversion device based on disturbance observation prediction control applying the bidirectional DC/DC conversion method based on disturbance observation prediction control according to any one of claims 1 to 6, characterized in that the bidirectional DC/DC conversion device based on disturbance observation prediction control comprises:
the discrete mathematical model building module is used for determining state variables, state equations and parameters of the bidirectional half-bridge DC/DC converter and building a discrete mathematical model of the converter;
the dynamic response speed control module is used for improving the dynamic response speed of the whole control system by the inner ring by adopting a model prediction control method on the basis of a power balance principle in the outer ring in the current control mode;
the working mode design module is used for respectively designing the bidirectional half-bridge DC/DC converter to be used as a Luenberger disturbance observer under a positive and negative working mode, namely a three-phase interleaved parallel Boost mode and a Buck mode according to a system discrete mathematical model;
the optimal control quantity adjusting module is used for compensating the observation state variable into the prediction model on line according to a system mathematical model and a Romberg disturbance observer, and respectively adjusting the optimal control quantity output by the converter under a positive and negative direction working mode by adopting an error feedback and observation disturbance feedforward control mode and combining with continuous set model prediction control based on a dead beat method;
and the pulse signal acquisition module is used for sending the optimal control quantity duty ratio to the CPS-PWM module to acquire a pulse signal of the three-phase switching tube.
8. A computer device, characterized in that the computer device comprises a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to carry out the steps of:
the method comprises the steps of calculating and establishing an inner and outer ring prediction control model of a converter working in a Boost mode and a Buck mode according to a mathematical model of a circuit, designing a Runberg disturbance observer in a positive and negative direction mode, compensating the model into the prediction model on line, adopting a mode of error feedback and disturbance feedforward observation, realizing model prediction control of a continuous set based on a dead-beat method, obtaining optimal control quantity in each working mode, and sending the optimal control duty ratio to a carrier phase-shift PWM (pulse width modulation) module CPS-PWM to obtain a switching pulse signal.
9. A computer-readable storage medium storing a computer program which, when executed by a processor, causes the processor to execute the bidirectional DC/DC conversion method based on disturbance observation prediction control according to any one of claims 1 to 6.
10. An information data processing terminal for realizing the function of the disturbance observation prediction control-based bidirectional DC/DC conversion apparatus according to claim 7.
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