CN115241909A - DAB converter optimization control method and device based on direct-current microgrid - Google Patents

DAB converter optimization control method and device based on direct-current microgrid Download PDF

Info

Publication number
CN115241909A
CN115241909A CN202210803008.6A CN202210803008A CN115241909A CN 115241909 A CN115241909 A CN 115241909A CN 202210803008 A CN202210803008 A CN 202210803008A CN 115241909 A CN115241909 A CN 115241909A
Authority
CN
China
Prior art keywords
ratio
phase
transmission power
dab converter
shifting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210803008.6A
Other languages
Chinese (zh)
Inventor
史伟超
张海燕
贾汝
刘斯万
朱凤玲
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Dianji University
Original Assignee
Shanghai Dianji University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Dianji University filed Critical Shanghai Dianji University
Priority to CN202210803008.6A priority Critical patent/CN115241909A/en
Publication of CN115241909A publication Critical patent/CN115241909A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H02J7/04—Regulation of charging current or voltage
    • H02J7/06—Regulation of charging current or voltage using discharge tubes or semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
    • 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
    • H02M1/0048—Circuits or arrangements for reducing losses
    • 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
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • 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
    • 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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H02M3/33584—Bidirectional converters
    • 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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • 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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/28—The renewable source being wind energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/40—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously

Abstract

The invention relates to a DAB converter optimization control method and device based on a direct-current microgrid, wherein the method comprises the following steps: acquiring a topological structure of the DAB converter; based on an extended phase-shift control strategy, the inductive current stress and the transmission power are obtained by controlling the switching phases between the H bridge arms and the bridges of the primary side and the secondary side; determining an adjusting mode for realizing soft switching of a switching tube based on the inductive current stress condition; establishing an extended phase shift control strategy optimization function, and performing optimization solution by a KKT (K-T) regulation method; sampling and calculating the voltage and the transmission power of a direct current bus at an input side and an output side to obtain a voltage transmission ratio and a real-time reference transmission power, inputting an extended phase-shifting control strategy optimization function to obtain an optimal phase-shifting ratio combination and a minimum current stress, wherein the optimal phase-shifting ratio combination comprises an inner-shifting ratio and an outer-shifting ratio; and designing a closed-loop controller based on the optimal phase shift ratio combination and the minimum current stress. Compared with the prior art, the invention has the advantages of high transmission efficiency and the like.

Description

DAB converter optimization control method and device based on direct-current microgrid
Technical Field
The invention relates to the field of direct-current micro-grids, in particular to a DAB converter optimization control method and device based on a direct-current micro-grid.
Background
In recent years, with the rapid development of distributed power supplies and energy storage systems, the demand of bidirectional isolation converters is increasing. A schematic diagram of a bidirectional isolation converter applied to a dc microgrid system is shown in fig. 2. The double-active full-bridge bidirectional DC-DC converter (DAB converter) has the advantages of simple control, high power density, high efficiency, modularization and the like due to symmetrical structure, becomes a core topological structure in the bidirectional isolation converter, and is widely applied to power electronic transformers, electric vehicles and the like. Meanwhile, the direct-current micro-grid is completely controllable and is dispatched by a large power grid, and each micro-source is simultaneously connected with a direct-current bus through a converter to flow energy. The direct-current microgrid is a novel energy supply scheme, and makes great contribution to the life of residents and the production of factories.
With the continuous development of power supply technology, the defects brought by a power supply mode based on the traditional theory become more and more obvious, for example, a converter supporting bidirectional transmission can only be used in medium and small power application occasions; under the high-power occasion, the power balance of multiple devices cannot be realized. In addition, the conventional converter adopts single phase-shifting control, only has one degree of freedom, and when the voltage transformation ratio is not matched, the switching tube loses the ZVS characteristic in the full-power range, so that the defects of increased inductive current stress, backflow power and loss, lower operation efficiency and the like of the converter are caused.
CN113765408A discloses a DAB converter turn-off loss optimization control method based on predictive control, which includes: acquiring input voltage, output reference voltage and output current of the double-active bridge converter; obtaining a phase shift amount under the single phase shift control according to the obtained input voltage, output reference voltage, output current and the single phase shift prediction controller; acquiring transmission power according to the phase shift amount under the control of the single phase shift; obtaining an internal phase shift quantity and an external phase shift quantity under the control of the extended phase shift according to a transmission power and turn-off loss optimization calculation model, wherein the obtaining process of the turn-off loss optimization calculation model is as follows: obtaining turn-off loss according to the relation between the converter inductive current and the turn-off loss of the switching element; performing optimal solution on the turn-off loss to obtain a turn-off loss optimization calculation model by taking the minimization of the turn-off loss under the current transmission power as a target; and controlling each switching element according to the inner phase shift amount and the outer phase shift amount. Although the method reduces the turn-off loss of the DAB converter by an extended phase-shifting control mode and improves the transmission efficiency to a certain extent, the further improvement of the transmission efficiency is limited without considering the stress of the inductive current and the reflux power.
Disclosure of Invention
The invention aims to provide a DAB converter optimization control method and device based on a direct current microgrid, control variables for controlling a double-active full bridge converter are obtained based on calculation of inductive current of the DAB converter, and then optimal modulation of the DAB converter is realized, the problem that in the prior art, the running efficiency of a system is low due to factors such as backflow power, device loss and the like is solved, and meanwhile, in the application occasion of high-power direct current power supply, a plurality of DAB converters are connected in parallel to realize balanced distribution of power.
The purpose of the invention can be realized by the following technical scheme:
a DAB converter optimization control method based on a direct current micro-grid comprises the following steps:
acquiring a topological structure of a DAB converter, wherein the topological structure of the DAB converter comprises a direct current input voltage, a primary side H bridge, an inductor, an isolation transformer, a secondary side H bridge and a direct current output voltage which are sequentially connected;
based on an extended phase-shifting control strategy, by controlling the switching phases between H bridge arms and bridges of a primary side and a secondary side of the DAB converter, the inductive current stress and the transmission power are obtained;
determining an adjusting mode for realizing soft switching of a switching tube based on an inductive current stress condition, wherein the inductive current stress condition is determined based on ZVS states of primary and secondary H-bridge switching tubes;
establishing an extended phase-shift control strategy optimization function based on a voltage transmission ratio, transmission power and inductive current stress, and performing optimization solution on the premise of meeting the regulation mode of a soft switch by a KKT regulation method;
sampling and calculating the voltage and the transmission power of the direct-current bus at the input side and the output side to obtain a voltage transmission ratio and real-time reference transmission power;
inputting a voltage transmission ratio and real-time reference transmission power into an extended phase-shifting control strategy optimization function to obtain an optimal phase-shifting ratio combination and a minimum current stress, wherein the optimal phase-shifting ratio combination comprises an inner-shifting ratio and an outer-shifting ratio;
and designing a closed-loop controller based on an optimal working point to realize the control of the switching tube, wherein the optimal working point is a working point corresponding to the optimal phase-shifting ratio combination and the minimum current stress.
The extended phase-shift control strategy comprises two working modes:
mode 1: d is not less than 0 1 ≤D 2 ≤1；
Mode 2: d is not less than 0 2 ＜D 1 ≤1；
Wherein D is 1 Is an inward shift phase ratio; d 2 The outward shift is compared.
The transmission power is:
Figure BDA0003735006430000031
wherein D is 1 Is an inward shift phase ratio; d 2 Is an outward shift phase ratio; p EPS * The transmission power is expressed in per unit value.
The inductive current stress is as follows:
Figure BDA0003735006430000032
wherein D is 1 Is an inward shift phase ratio; d 2 Is an outward shift phase ratio; i.e. i L * (t) is the inductor current stress; k is voltage transmission ratio and k > 1, k =V in /(nV o )，V in For input voltage, V o N is the transformation ratio of the high-frequency transformer for the output voltage.
The inductor current stress conditions are as follows: i.e. i L (t 1 )≤0,i L (t 3 ) More than or equal to 0, under the condition, the primary and secondary side H bridge switching tubes are in ZVS states; wherein i L Is the inductor current stress, t 1 Realizing critical time t for primary side H bridge soft switch 3 Realizing critical time for secondary side H bridge soft switch.
In the mode 1, the adjustment mode for realizing the soft switching of the switching tube is as follows:
Figure BDA0003735006430000033
wherein k is a voltage transmission ratio and k > 1, k = V in /(nV o )，V in For input voltage, V o N is the transformation ratio of the high-frequency transformer for the output voltage.
The standard form of the optimization function of the extended phase-shifting control strategy is as follows:
Figure BDA0003735006430000034
wherein, X = (D) 1 ,D 2 ) (ii) a Y (X) is an objective function; p EPS * -P 0 * As a constraint of equality, P EPS * For transmission power, P 0 * For real-time reference transmission power, P EPS * And P 0 * All expressed in per unit value; b is j (j =1,2, \8230;, q) is an inequality constraint condition, and q represents the number of inequalities.
The extended phase-shift control strategy comprises two working modes:
mode 1: d is not less than 0 1 ≤D 2 ≤1；
Mode 2: d is not less than 0 2 ＜D 1 ≤1；
Under the mode 1, the optimal solution of the extended phase shift control strategy optimization function meets the KKT condition:
Figure BDA0003735006430000041
solving to obtain the optimal phase shift ratio combination and the minimum current stress as follows:
Figure BDA0003735006430000042
Figure BDA0003735006430000043
wherein D is 1 Is an inward shift phase ratio; d 2 Is an outward shift phase ratio; k is voltage transmission ratio and k is more than 1, k = V in /(nV o )，V in For input voltage, V o Is the output voltage, and n is the transformation ratio of the high-frequency transformer; lambda is a multiplier of the real-time transmission power equality constraint condition; mu.s 1 ,μ 2 ,μ 3 ,μ 4 ,μ 5 And multipliers corresponding to each inequality constraint condition.
In the mode 1, the phase ratio D is shifted inward 1 And corresponding real-time reference transmission power P 0 * Respectively, the ranges of (A) are:
Figure BDA0003735006430000044
a DAB converter optimization control device based on a direct current micro-grid comprises:
the data acquisition module is used for acquiring the topological structure of the DAB converter and transmitting the topological structure to the extended phase-shifting control module;
an extended phasing control module comprising a memory, a processor, and a program stored in said memory, said processor implementing the method as described above when executing said program;
and the switching tube control module is used for realizing the control of the switching tube based on the output of the extended phase-shifting control module.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, an internal shift ratio is added based on an extended phase shift control strategy, and the inductor current stress is optimized by a KKT condition method under the condition that the original topological structure and circuit parameters are not changed, so that the inductor current stress is reduced, the loss is reduced, the transmission efficiency of the converter is improved, and the method has important significance in promoting the development of a direct current power distribution network and renewable energy sources.
Drawings
FIG. 1 is a flow chart of a method of the present invention;
FIG. 2 is a block diagram of a DC microgrid system;
FIG. 3 is a diagram of a DAB converter topology, wherein V 1 For input voltage, V 2 To output a voltage, C 1 、C 2 For isolating the capacitor, S 1 、S 2 、S 3 、S 4 Is a primary side switching tube, Q 1 、Q 2 、Q 3 、Q 4 Is opened for the minor edgeTurn off the tube, L is inductance, V p Is the output voltage, V, of the primary side H-bridge s The primary voltage of the high-frequency transformer;
FIG. 4 is an extended phase shift control timing diagram, where D 1 T S Is the angle between the diagonal drive signals of the primary bridge type, D 2 T S Is the angle of the driving signal between the two full-bridge switching tubes.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
A DAB converter optimization control method based on a direct current micro-grid is disclosed, as shown in FIG. 1, and comprises the following steps:
(1) Acquiring a topological structure of the DAB converter;
the energy bidirectional flow is the core of the invention, and the energy bidirectional flow is realized by various topological structures, and in order to be applied in high-power occasions, a double-active full-bridge topological structure (namely a DAB converter topological structure) is selected. The topological structure of the DAB converter comprises a direct current input voltage, a primary side H bridge, an inductor, an isolation transformer, a secondary side H bridge and a direct current output voltage which are connected in sequence, and is shown in figure 3. The DAB converter is composed of two H bridges and a high-frequency isolation transformer, and has the advantages of electric isolation, high power density, small switching stress, realization of ZVS (zero voltage switching) characteristic, modularized symmetrical structure and the like.
(2) Based on an extended phase-shifting control strategy, by controlling the switching phases between H bridge arms and bridges of a primary side and a secondary side of the DAB converter, the inductive current stress and the transmission power are obtained;
after the topological structure of the circuit is determined, in order to enable the energy of the transformer to flow in two directions, the input and output voltages have good wide applicability, and the switching of the two-way electric energy transmission mode can be realized only by adding a proper control strategy.
And analyzing the basic principle and the working characteristics of single phase-shift control, and deriving the expressions of the transmission power, the current stress and the phase shift ratio of the single phase-shift control and the ZVS (zero voltage switching) characteristics of the switching tube. The direction of the transmission power can be changed by adjusting the phase shift ratio, and the magnitude of the output voltage can be changed. However, when the voltage transformation ratios of the two ends of the converter are not matched or the converter is operated under a light load, the problems of large inductive current stress, increased backflow power, difficulty in realizing soft switching and the like occur. Therefore, for the problems of the DAB converter under the single phase shift control, in this embodiment, an extended phase shift control strategy is adopted, a phase shift angle is increased, and the control degree is not too complex, so that the converter can increase the adjustment range of the transmission power, the operation is more flexible, and the current stress is obviously reduced.
The extended phase shift control strategy can be divided into two working modes according to the magnitude relation of two degrees of freedom:
mode 1: d is not less than 0 1 ≤D 2 ≤1；
Mode 2: d is not less than 0 2 ＜D 1 ≤1；
Wherein D is 1 Is an inward shift phase ratio; d 2 The outward shift is compared.
The transmission power is:
Figure BDA0003735006430000061
wherein D is 1 Is an inward shift phase ratio; d 2 Is an outward shift phase ratio; p EPS * The transmission power is expressed in per unit value.
The inductive current stress is as follows:
Figure BDA0003735006430000062
wherein i L * (t) is the inductor current stress; k is voltage transmission ratio and k > 1, k =V in /(nV o )，V in For the input voltage, V o N is the transformation ratio of the high-frequency transformer for the output voltage. Further analysis is then only done in mode 1, and mode 2 can be so.
(3) Determining an adjusting mode for realizing soft switching of a switching tube based on an inductive current stress condition, wherein the inductive current stress condition is determined based on ZVS states of primary and secondary H-bridge switching tubes;
the switching loss has a large influence on the transmission efficiency, and in order to ensure efficient transmission, soft switching of the switching tube needs to be realized. The inductor current stress conditions are as follows: i all right angle L (t 1 )≤0,i L (t 3 ) Not less than 0, under the condition, the primary and secondary side H bridge switching tubes are in ZVS state; wherein i L Is the inductor current stress, t 1 Realizing critical time t for primary side H bridge soft switch 3 Realizing critical time for secondary side H bridge soft switch.
In the mode 1, the adjustment mode for realizing the soft switching of the switching tube is as follows:
Figure BDA0003735006430000071
(4) Establishing an extended phase-shift control strategy optimization function based on a voltage transmission ratio, transmission power and inductive current stress, and performing optimization solution on the premise of meeting the regulation mode of a soft switch by a KKT regulation method;
aiming at the problem that different phase shift ratio combinations cause different current stress and reflux power under an extended phase shift control strategy, the extended phase shift control strategy is further improved to reduce the inductive current stress as an optimization target, an optimization function is established through a KKT condition method, and a proper phase shift ratio combination is searched, so that the loss can be reduced and the high transmission efficiency can be kept under the working condition that the voltage transformation ratio of the converter is not matched or the light load is carried out.
The standard form of the optimization function of the extended phase-shifting control strategy is as follows:
Figure BDA0003735006430000072
wherein, X = (D) 1 ,D 2 ) (ii) a Y (X) is an objective function; p is EPS * -P 0 * Is equal toConstraint of formula P EPS * For transmission power, P 0 * For real-time reference transmission power, P EPS * And P 0 * All expressed in per unit value; b j (j =1,2, \8230;, q) is an inequality constraint condition, and q represents the number of inequalities.
Under the mode 1, the optimal solution of the extended phase shift control strategy optimization function meets the KKT condition:
Figure BDA0003735006430000073
solving to obtain the optimal phase shift ratio combination and the minimum current stress as follows:
Figure BDA0003735006430000081
Figure BDA0003735006430000082
wherein, λ is a multiplier of the real-time transmission power equality constraint condition; mu.s 1 ,μ 2 ,μ 3 ,μ 4 ,μ 5 And multipliers corresponding to each inequality constraint condition.
Internal shift phase ratio D 1 And corresponding real time reference transmission power P 0 * Respectively, the ranges of (A) are:
Figure BDA0003735006430000083
in this preferred embodiment, the timing chart of the extended phase shift control is shown in fig. 4. Through the solution of the optimization function, the optimal group of the inward shift phase ratio and the outward shift phase ratio of the DAB converter can be obtained under the condition of giving the real-time reference transmission power and the voltage transmission ratio, and the constraint condition that all the switching tubes can realize ZVS at the moment is considered, so that the DAB can obtain the optimal soft switching performance through the optimal solution. And under the traditional phase shift control and the optimized expanded phase shift control strategy, the inductive current stress curve of the converter is compared, and the result shows that the inductive current stress is smaller under the optimized control phase shift control. As the input-to-output voltage transformation ratio increases, the inductor current stress decreases more significantly.
(5) Sampling and calculating the voltage and the transmission power of the input and output side direct current bus to obtain a voltage transmission ratio k and a real-time reference transmission power P 0 * ；
(6) The voltage transmission ratio k and the real-time reference transmission power P 0 * Inputting an extended phase-shift control strategy optimization function to obtain an optimal phase-shift ratio combination and a minimum current stress, wherein the optimal phase-shift ratio combination comprises an inner shift ratio and an outer shift ratio;
(7) And designing a closed-loop controller based on an optimal working point to realize the control of the switching tube, wherein the optimal working point is a working point corresponding to the optimal phase-shifting ratio combination and the minimum current stress.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the above teachings. Therefore, the technical solutions that can be obtained by a person skilled in the art through logical analysis, inference or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection defined by the claims.

Claims (10)

1. A DAB converter optimization control method based on a direct current micro-grid is characterized by comprising the following steps:
acquiring a topological structure of a DAB converter, wherein the topological structure of the DAB converter comprises a direct current input voltage, a primary side H bridge, an inductor, an isolation transformer, a secondary side H bridge and a direct current output voltage which are sequentially connected;
based on an extended phase-shifting control strategy, by controlling the switching phases between H bridge arms and bridges of a primary side and a secondary side of the DAB converter, the inductive current stress and the transmission power are obtained;
determining an adjusting mode for realizing soft switching of a switching tube based on an inductive current stress condition, wherein the inductive current stress condition is determined based on ZVS states of primary and secondary H-bridge switching tubes;
establishing an extended phase shift control strategy optimization function based on a voltage transmission ratio, transmission power and inductive current stress, and performing optimization solution on the premise of meeting the regulation mode of a soft switch by a KKT regulation method;
sampling and calculating the voltage and the transmission power of the direct-current bus at the input side and the output side to obtain a voltage transmission ratio and real-time reference transmission power;
inputting a voltage transmission ratio and real-time reference transmission power into an extended phase-shifting control strategy optimization function to obtain an optimal phase-shifting ratio combination and a minimum current stress, wherein the optimal phase-shifting ratio combination comprises an inner-shifting ratio and an outer-shifting ratio;
and designing a closed-loop controller based on an optimal working point to realize the control of the switching tube, wherein the optimal working point is a working point corresponding to the optimal phase-shifting ratio combination and the minimum current stress.
2. A DAB converter optimization control method based on DC micro-grid according to claim 1 characterized in that said extended phase shift control strategy includes two operation modes:
mode 1: d is not less than 0 1 ≤D 2 ≤1；
Mode 2: d is more than or equal to 0 2 ＜D 1 ≤1；
Wherein D is 1 Is an inward shift phase ratio; d 2 The outward shift is compared.
3. A DAB converter optimization control method based on DC micro-grid according to claim 1, characterized in that the transmission power is:
Figure FDA0003735006420000011
wherein D is 1 Is an inward shift phase ratio; d 2 Is an outward shift phase ratio; p EPS * For transmission power, in per unit formThe formula is shown.
4. A DAB converter optimization control method based on DC microgrid according to claim 1, characterized in that the inductor current stress is:
Figure FDA0003735006420000021
wherein D is 1 Is an inward shift phase ratio; d 2 Is an outward shift phase ratio; i.e. i L * (t) is the inductor current stress; k is voltage transmission ratio and k > 1, k =V in /(nV o )，V in For input voltage, V o N is the transformation ratio of the high-frequency transformer for the output voltage.
5. A DAB converter optimization control method based on a direct current micro-grid according to claim 1, characterized in that the inductor current stress condition is as follows: i.e. i L (t 1 )≤0,i L (t 3 ) Not less than 0, under the condition, the primary and secondary side H bridge switching tubes are in ZVS state; wherein i L Is the inductor current stress, t 1 Realizing critical time t for primary side H bridge soft switch 3 Realizing critical time for secondary side H bridge soft switch.
6. A DAB converter optimization control method based on a direct current micro-grid according to claim 2, characterized in that in the mode 1, the soft switching of the switching tubes is realized by the following regulation mode:
Figure FDA0003735006420000022
wherein k is a voltage transmission ratio and k > 1, k = V in /(nV o )，V in For input voltage, V o N is the transformation ratio of the high-frequency transformer for the output voltage.
7. A DAB converter optimization control method based on a direct current micro-grid according to claim 1, characterized in that the standard form of the extended phase shift control strategy optimization function is:
Figure FDA0003735006420000023
wherein, X = (D) 1 ,D 2 ) (ii) a Y (X) is an objective function; p EPS * -P 0 * As a constraint of equality, P EPS * For transmission power, P 0 * For real-time reference transmission power, P EPS * And P 0 * All are expressed in the form of per unit values; b is j (j =1,2, \8230;, q) is an inequality constraint condition, and q represents the number of inequalities.
8. A DAB converter optimization control method based on DC micro-grid according to claim 7, characterized in that the extended phase shift control strategy comprises two operation modes:
mode 1: d is not less than 0 1 ≤D 2 ≤1；
Mode 2: d is more than or equal to 0 2 ＜D 1 ≤1；
In mode 1, the optimal solution of the extended phase shift control strategy optimization function satisfies the KKT condition:
Figure FDA0003735006420000031
solving to obtain the optimal phase shift ratio combination and the minimum current stress as follows:
Figure FDA0003735006420000032
Figure FDA0003735006420000033
wherein D is 1 Is an inward shift phase ratio; d 2 Is an outward shift phase ratio; k is voltage transmission ratio and k > 1, k =V in /(nV o )，V in For input voltage, V o N is the transformation ratio of the high-frequency transformer; lambda is a multiplier of the real-time transmission power equality constraint condition; mu.s 1 ,μ 2 ,μ 3 ,μ 4 ,μ 5 And multipliers corresponding to each inequality constraint condition.
9. A DAB converter optimization control method based on DC micro-grid according to claim 8 characterized in that in mode 1, the phase ratio of inner shift is D 1 And corresponding real time reference transmission power P 0 * Respectively as follows:
Figure FDA0003735006420000034
10. a DAB converter optimization control device based on a direct current micro-grid is characterized by comprising:
the data acquisition module is used for acquiring the topological structure of the DAB converter and transmitting the topological structure to the extended phase-shifting control module;
an extended phase shift control module comprising a memory, a processor, and a program stored in the memory, the processor when executing the program implementing the method of any of claims 1-9;
and the switching tube control module is used for realizing the control of the switching tube based on the output of the extended phase-shifting control module.
CN202210803008.6A 2022-07-07 2022-07-07 DAB converter optimization control method and device based on direct-current microgrid Pending CN115241909A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210803008.6A CN115241909A (en) 2022-07-07 2022-07-07 DAB converter optimization control method and device based on direct-current microgrid

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210803008.6A CN115241909A (en) 2022-07-07 2022-07-07 DAB converter optimization control method and device based on direct-current microgrid

Publications (1)

Publication Number Publication Date
CN115241909A true CN115241909A (en) 2022-10-25

Family

ID=83671933

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210803008.6A Pending CN115241909A (en) 2022-07-07 2022-07-07 DAB converter optimization control method and device based on direct-current microgrid

Country Status (1)

Country Link
CN (1) CN115241909A (en)

Similar Documents

Publication Publication Date Title
CN114050722B (en) DAB-based direct power model prediction and PI composite control method
CN108964476B (en) Control method of isolated bidirectional AC/DC converter based on double active bridges
CN108288917B (en) Triple phase shift dead-beat optimization control method of full-bridge DC-DC converter
CN111817570A (en) DAB converter wide-range regulation and control method based on multi-mode model prediction
CN112910271A (en) Expanded phase-shift controlled double-active-bridge converter current stress optimization control method
CN111817566A (en) LLCT resonant bidirectional DC converter
CN114825968A (en) Asymmetric duty ratio and internal phase shift hybrid control method
CN109302072B (en) Series-input multi-port-output resonant DC converter and control method thereof
CN112953245A (en) Full-load range soft switching control method for double-active bridge converter
CN113098285A (en) Method for optimally controlling reflux power of double-active-bridge converter under extended phase-shift control
CN117081403A (en) Mixed modulation method applied to wide output voltage CLLC converter
CN114006541B (en) Efficiency optimization control method for double-active half-bridge direct-current converter
CN115241909A (en) DAB converter optimization control method and device based on direct-current microgrid
CN115694166A (en) Optimal design method of hybrid bidirectional LLC-DAB converter
CN114744886A (en) Intelligent PI control method of double-active full-bridge converter
CN113904560A (en) DAB converter multi-target unified control method based on triple phase-shift control
CN114430234B (en) Soft switch and current stress optimization method of DAB converter
CN113794381B (en) SCDAB-CLLLC composite direct-current transformer with wide voltage regulation range and control method thereof
CN116317595A (en) Four-degree-of-freedom efficiency optimization control method suitable for bidirectional direct current converter of electric locomotive
CN113708636B (en) Energy storage type bidirectional direct current conversion circuit and method for wide-voltage gain battery
CN116418239B (en) Dual active bridge circuit, power supply and DC-DC converter
CN117439372A (en) Multi-objective optimized modulation method for DAB converter
CN109039082B (en) Backflow power optimization method suitable for modular multilevel direct current transformer
CN117792036A (en) Multi-objective optimization method and device for DAB converter based on soft switch
CN114499212A (en) Current stress optimization expansion phase shift control method of double-active full-bridge DC-DC converter

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination