CN112701917A - Method and device for reducing reactive power of converter - Google Patents

Method and device for reducing reactive power of converter Download PDF

Info

Publication number
CN112701917A
CN112701917A CN202011496625.3A CN202011496625A CN112701917A CN 112701917 A CN112701917 A CN 112701917A CN 202011496625 A CN202011496625 A CN 202011496625A CN 112701917 A CN112701917 A CN 112701917A
Authority
CN
China
Prior art keywords
converter
voltage
duty ratio
power
secondary side
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.)
Granted
Application number
CN202011496625.3A
Other languages
Chinese (zh)
Other versions
CN112701917B (en
Inventor
石如心
吴立东
王丽杰
曹善桥
王娟
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.)
China Datang Group Solar Energy Industry Co ltd
Datang Renewable Energy Test And Research Institute Co ltd
Original Assignee
China Datang Group Solar Energy Industry Co ltd
Datang Renewable Energy Test And Research Institute Co ltd
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 China Datang Group Solar Energy Industry Co ltd, Datang Renewable Energy Test And Research Institute Co ltd filed Critical China Datang Group Solar Energy Industry Co ltd
Priority to CN202011496625.3A priority Critical patent/CN112701917B/en
Publication of CN112701917A publication Critical patent/CN112701917A/en
Application granted granted Critical
Publication of CN112701917B publication Critical patent/CN112701917B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The embodiment of the disclosure provides a method and a device for reducing the reactive power of a converter, wherein the method obtains a constraint condition for limiting the reactive power according to a phase shifting duty ratio of a switching signal of a primary side switching tube, a phase shifting duty ratio of a switching signal of a secondary side switching tube and a phase shifting duty ratio corresponding to a phase shifting angle of a voltage between middle points of an original secondary side bridge arm; under the premise that the constraint condition is met, the maximum transfer power of the converter is obtained by controlling the item shifting duty ratio of a switching signal of the primary side switching tube and the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm; and on the premise of maximizing the transmitted power of the converter, controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary bridge arms again, and simplifying the control step of reducing the reactive power of the converter. The method improves the transmission power of the converter to the maximum extent and is easy to adjust the power output under the premise of ensuring the elimination of reactive power and reducing loss.

Description

Method and device for reducing reactive power of converter
Technical Field
The invention belongs to the technical field of new energy distributed power generation and power electronics, and particularly relates to a method and a device for reducing reactive power of a converter.
Background
The distributed power generation has the advantages of less environmental pollution, flexible installation place, high energy utilization rate, less power transmission line loss and the like, is one of important development trends of future power systems, and is an important way for solving energy crisis and environmental pollution by utilizing renewable energy sources to generate power. However, in the renewable energy power generation system, due to the influence of weather and weather, the renewable energy has the problems of intermittency and randomness, and an energy storage device needs to be introduced and used in combination with the renewable energy power generation unit so as to provide stable and continuous electric energy. The bidirectional transfer of energy between the energy storage device and the DC bus is typically controlled by a bidirectional DC-DC converter. The double-active full-bridge bidirectional DC-DC converter has the advantages of relatively small voltage and current stress of a switching device, symmetrical structure, easiness in realizing zero-voltage switching of a switching tube and the like, and is suitable for medium and high power occasions.
At present, the control methods which have been proposed for the dual-active full-bridge converter to improve the conversion efficiency and reduce the reactive power are mostly realized by using a phase-shift control method and a PWM plus shift control method. The document 'the isolated bidirectional double-active bridge converter for eliminating reactive power and improving the system efficiency adopts novel double-phase-shift control' and proposes a novel method for controlling the reactive power by PWM plus phase-shift control. However, this method can only reduce the reactive power on both sides of the converter properly or only eliminate the reactive power on one side of the primary side or the secondary side of the converter, but cannot completely eliminate the reactive power on both sides. The existence of reactive power can cause the over charge and discharge of a direct current side capacitor and a battery, and the service life of the device is shortened.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method and a device for reducing the reactive power of a converter, which can reduce the reactive loss of a system and improve the transmission power of the converter.
In a first aspect, an embodiment of the present invention provides a method for reducing reactive power of a converter, including:
according to the primary sidePhase-shift duty ratio D of switching signal of switch-off1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000011
Obtaining a constraint condition for limiting reactive power;
on the premise that the constraint condition is met, the phase-shifting duty ratio D of the switching signal of the primary side switching tube is controlled1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure BDA0002842349960000012
Obtaining the maximum transmission power of the converter;
and on the premise of maximizing the transmitted power of the converter, controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary bridge arms again, and simplifying the control step of reducing the reactive power of the converter.
Optionally, the constraint condition for limiting the reactive power is:
Figure BDA0002842349960000021
D2＝1+k(D1-1)
wherein k is n V1/V2N is the transformer transformation ratio, V1Is the primary side DC side voltage, V2Is the secondary side direct current side voltage.
Optionally, the term-shift duty cycle D of the switching signal through controlling the primary side switching tube1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure BDA0002842349960000022
Obtaining maximum transfer power of the converter, comprising:
the average power transfer over one switching cycle of the converter is expressed as:
Figure BDA0002842349960000023
wherein L is the inductance on the transformer side, fsIs the switching frequency. When it is satisfied with
Figure BDA0002842349960000024
In the case of constraint conditions, the maximum value of P is discussed in different cases, and the expression is as follows:
Figure BDA0002842349960000025
setting D1As a main control parameter, PmaxThe expression of (a) is:
Figure BDA0002842349960000026
when D is present1In (D)12And, 1) monotonic variation in power control is achieved, and D is set so that P has a maximum value1Comprises the following steps:
Figure BDA0002842349960000027
optionally, the method according to claim 1, wherein the step of controlling the phase-shift duty ratio corresponding to the phase-shift angle of the voltage between the midpoints of the original secondary-side bridge arms to simplify the control step of reducing the reactive power of the converter under the premise of maximizing the power transfer of the converter includes:
Figure BDA0002842349960000028
optionally, the phase-shift duty ratio D is determined according to the switching signal of the primary side switching tube1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000029
Before obtaining the constraint condition for limiting the reactive power, the method further comprises:
the conditions for generating reactive current are determined.
Optionally, the condition for determining that the reactive current is generated is as follows:
when the middle point of the primary bridge arm outputs a voltage Vh1Or the midpoint voltage V of the secondary side bridge armh2And the transformer side inductor current iLWhen the polarities are different, reactive current can be generated on the primary side or the secondary side.
In a second aspect, an embodiment of the present invention further provides an apparatus for reducing reactive power of a converter, including:
a constraint condition determining module for determining a shift duty ratio D according to the switching signal of the primary side switching tube1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000031
Obtaining a constraint condition for limiting reactive power;
a maximum transfer power acquisition module for controlling the phase shift duty ratio D of the switching signal of the primary side switching tube on the premise that the constraint condition is satisfied1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure BDA0002842349960000032
Obtaining the maximum transmission power of the converter;
the device for reducing the reactive power of the converter is used for controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arms again on the premise of maximizing the power transmission of the converter, and simplifies the control steps for reducing the reactive power of the converter.
Optionally, the constraint condition for limiting the reactive power is:
Figure BDA0002842349960000033
D2＝1+k(D1-1)
wherein k is n V1/V2N is the transformer transformation ratio, V1Is the primary side DC side voltage, V2Is the secondary side direct current side voltage.
Optionally, the apparatus further comprises:
and the condition determining module is used for determining the condition for generating the reactive current.
Optionally, the condition determining module is further configured to:
when the middle point of the primary bridge arm outputs a voltage Vh1Or the midpoint voltage V of the secondary side bridge armh2And the transformer side inductor current iLWhen the polarities are different, reactive current can be generated on the primary side or the secondary side.
The method and the device for reducing the reactive power of the converter improve the transmission power of the converter by reducing the reactive loss of a system. According to the phase shift duty ratio D1 of the switching signal of the primary side switching tube, the phase shift duty ratio D2 of the switching signal of the secondary side switching tube and the phase shift duty ratio corresponding to the phase shift angle of the voltage between the middle points of the original secondary side bridge arm
Figure BDA0002842349960000034
Obtaining a constraint condition for limiting reactive power; on the premise that the constraint condition is met, the item shifting duty ratio D1 of a switching signal of the primary side switching tube and the item shifting duty ratio corresponding to the item shifting angle of the voltage between the midpoints of the primary side bridge arm and the secondary side bridge arm are controlled
Figure BDA0002842349960000035
Obtaining the maximum transmission power of the converter; and on the premise of maximizing the transmitted power of the converter, controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary bridge arms again, and simplifying the control step of reducing the reactive power of the converter. The method can maximally improve the transmission power of the converter and easily adjust the power transmission under the premise of ensuring the elimination of reactive power and reducing lossAnd (4) determining the size.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure. It is to be understood that the drawings in the following description are merely exemplary of the disclosure, and that other drawings may be derived from those drawings by one of ordinary skill in the art without the exercise of inventive faculty.
FIG. 1 is a schematic flow chart of a method for reducing converter reactive power according to an embodiment of the present invention;
fig. 2 is a topology diagram of a dual-active full-bridge converter according to an embodiment of the present invention;
FIG. 3 is a simplified schematic diagram of a converter provided in accordance with an embodiment of the present invention;
FIG. 4 is a waveform diagram illustrating a conventional PWM plus phase shift control according to an embodiment of the present invention;
FIG. 5 is a graph of converter power transfer provided by an embodiment of the present invention;
FIG. 6 is a waveform diagram of an improved dual PWM plus shift control according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of an apparatus for reducing reactive power of a converter according to an 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 described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and should not be construed as limiting the scope of the invention.
Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the subject matter of the present disclosure can be practiced without one or more of the specific details, or with other methods, apparatus, steps, etc. In other instances, well-known structures, methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.
Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present disclosure, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. The symbol "/" generally indicates that the former and latter associated objects are in an "or" relationship.
In the present disclosure, unless otherwise expressly specified or limited, the terms "connected" and the like are to be construed broadly, e.g., as meaning electrically connected or in communication with each other; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present disclosure can be understood by those of ordinary skill in the art as appropriate.
Fig. 1 shows a schematic flow chart of a method for reducing reactive power of a converter according to an embodiment of the present invention, as shown in fig. 1, the method includes the following steps:
101. based on primary switching tubesPhase-shift duty cycle D of switching signal1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000051
Obtaining a constraint condition for limiting reactive power;
the constraint condition for limiting the reactive power is as follows:
Figure BDA0002842349960000052
D2＝1+k(D1-1)
wherein k is n V1/V2N is the transformer transformation ratio, V1Is the primary side DC side voltage, V2Is the secondary side direct current side voltage.
102. On the premise that the constraint condition is met, the phase-shifting duty ratio D of the switching signal of the primary side switching tube is controlled1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure BDA0002842349960000053
Obtaining the maximum transmission power of the converter;
in step 102, the average power transfer expression for one switching cycle of the converter is:
Figure BDA0002842349960000054
wherein L is the inductance on the transformer side, fsIs the switching frequency. When it is satisfied with
Figure BDA0002842349960000055
In the case of constraint conditions, the maximum value of P is discussed in different cases, and the expression is as follows:
Figure BDA0002842349960000056
setting D1As a main control parameter, PmaxThe expression of (a) is:
Figure BDA0002842349960000057
when D is present1In (D)12And, 1) monotonic variation in power control is achieved, and D is set so that P has a maximum value1Comprises the following steps:
Figure BDA0002842349960000058
103. and on the premise of maximizing the transmitted power of the converter, controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary bridge arms again, and simplifying the control step of reducing the reactive power of the converter.
The method improves the transmission power of the converter by reducing the reactive loss of the system. Phase-shift duty ratio D according to switching signal of primary side switching tube1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000059
Obtaining a constraint condition for limiting reactive power; on the premise that the constraint condition is met, the phase-shifting duty ratio D of the switching signal of the primary side switching tube is controlled1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure BDA0002842349960000061
Obtaining the maximum transmission power of the converter; and on the premise of maximizing the transmitted power of the converter, controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary bridge arms again, and simplifying the control step of reducing the reactive power of the converter. The method improves the conversion to the maximum extent on the premise of ensuring the elimination of reactive power and reducing lossThe power transmission device transmits power and is easy to adjust the power output.
The method is extended based on the method for eliminating the reactive power, the control strategy of the double-active full-bridge bidirectional DC-DC converter is explored, the double PWM adding and shifting control method of the double-active full-bridge converter is designed, and the three-step method for eliminating the reactive power is obtained. The method improves the working efficiency of the converter in a wide input or output voltage range, and has important significance for efficiently utilizing renewable energy.
In the prior art, a control method for reducing reactive power by using a dual PWM plus shift control method for a converter has not been explicitly provided. In order to overcome the defects of the existing control method of the dual-active-bridge converter and better improve the transmission efficiency, a better control method for improving the conversion efficiency and reducing the reactive power of the dual-active-bridge converter for energy storage is required to be found, and the optimal control of the dual-active-bridge converter is realized under the more universal condition.
Through the analysis, the reactive power control method of the converter is mainly summarized into three steps, the reason for generating the reactive power is found, and the constraint condition for eliminating the reactive power is obtained; setting D under the condition of power maximization1A value of (d); according to and D1Simplifying the tuning D2And
Figure BDA0002842349960000062
the value of (c).
The invention has the beneficial effects that:
the invention provides a method for reducing the reactive power generated by a converter and improving the transmission power, aiming at solving the problem of the reactive power generated by the converter. The invention provides a new method for reducing the reactive power of the double-active full-bridge converter for energy storage. Compared with the prior art, the method has the advantages that:
1. the method improves the transmission power of the converter to the maximum extent and is easy to adjust the power output under the premise of ensuring the elimination of reactive power and reducing loss.
2. The method has certain universality and is easy to realize, and the reactive power of the transformer can be controlled no matter the transformer works in a boosting mode or a voltage reduction mode.
3. The method can meet the requirement of eliminating reactive power under the condition that the voltage of the converter is changed in a large range.
The above method is described in detail below by way of specific examples.
The invention provides a universal control method for reducing the reactive power and controlling the power of a double-active full-bridge converter, which is improved on the basis of the traditional control method and realizes the improvement of the efficiency of the transmission power of the double-active full-bridge converter by using a simpler control method. The invention provides a new method for reducing the reactive power of the double-active full-bridge converter for energy storage. The method specifically comprises the following steps:
step 1: analyzing the essential reason of the reactive power generated by the converter by a traditional double-active full-bridge converter PWM and phase-shift control method;
in step 1, as shown in the topological diagram of the dual-active full-bridge DC-DC converter shown in fig. 2, the meanings of the variables in the converter are explicitly marked, and when the converter uses the first single PWM plus phase shift control method, only Q is controlled3And Q4Switching signal relative to Q1And Q2Phase-shift angle duty cycle D of switching signal1Shifted duty ratio corresponding to phase shift angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000071
Input and output current i of both sides of primary side and secondary side of converter1、i2Reactive current appears;
when the converter uses the second single PWM plus phase shift control method, i.e. Q is controlled simultaneously3And Q4Switching signal relative to Q1And Q2Phase-shift angle duty cycle D of switching signal1And Q7And Q8Switching signal relative to Q5And Q6Phase-shift angle duty cycle D of switching signal2(D1＝D2) Shifted duty ratio corresponding to phase shift angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000072
When in
Figure BDA0002842349960000073
When the reactive current disappears, only the primary side has reactive current.
Thus determining the generation of a reactive current (i)1、i2<0) The reason for (2) is: when the middle point of the primary bridge arm outputs a voltage Vh1Or the midpoint voltage V of the secondary side bridge armh2And the transformer side inductor current iLWhen the polarities are different, reactive current can be generated on the primary side or the secondary side. Fig. 3 shows a simplified circuit diagram of the output voltage and the inductor current of the primary and secondary bridge arms.
Step 2: according to the reason summarized above for generating reactive power, as shown in fig. 4, the conventional PWM plus phase shift control waveform diagram can be used to observe the reactive power generated by the primary side or the secondary side in the conventional method3And Q4Switching signal relative to Q1And Q2Phase-shift angle duty cycle D of switching signal1,Q7And Q8Switching signal relative to Q5And Q6Phase-shift angle duty cycle D of switching signal2Shifted duty ratio corresponding to phase shift angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000074
Three variables, namely, elimination of reactive power is realized, and constraint conditions for limiting the reactive power are deduced;
in step 2, in order to make the output voltage of the primary and secondary side bridges and the inductive current have the same polarity in one switching period and eliminate the reactive current at two sides, i needs to be satisfiedL(t1)、iL(t2)、iL(t5)、iL(t6)＝0。
The expression to be satisfied is:
|ΔiL(t4-t2)|＝|ΔiL(t5-t4)|
the simplified expression is:
D2＝1+k(D1-1)
wherein k is n V1/V2N is the transformer transformation ratio, V1Is the primary side DC side voltage, V2Is the secondary side direct current side voltage.
Two constraint conditions for eliminating the reactive power are obtained through analysis:
Figure BDA0002842349960000075
D2＝1+k(D1-1)
and step 3: d is set to ensure the power transmission efficiency of the converter on the premise of meeting the second step1To maximize transmission power and optimize power control monotonicity; the control method is realized to maximize the transmission power as shown in the power transmission curve diagram of the converter shown in fig. 5. Fig. 6 is a waveform diagram of the improved dual PWM additive shift control, from which it can be seen that the reactive current of the improved control method has been eliminated.
In step 3, to further satisfy the requirement of maximizing the transmission power, it is necessary to satisfy D in step 22And D1Constraint conditions, and control
Figure BDA0002842349960000076
And D1To achieve maximum delivered power.
The average power transfer over one switching cycle of the converter is expressed as:
Figure BDA0002842349960000077
wherein L is the inductance on the transformer side, fsIs the switching frequency. When it is satisfied with
Figure BDA0002842349960000081
In the case of constraint conditions, the maximum value of P is discussed in different cases, and the expression is as follows:
Figure BDA0002842349960000082
setting D1As a main control parameter, PmaxThe expression of (a) is:
Figure BDA0002842349960000083
when D is present1In (D)12And 1), monotonic variation in power control can be achieved. To make P have a maximum value, D is set1Comprises the following steps:
Figure BDA0002842349960000084
in practical case will D1Is controlled at (D)12And 1) the optimization of the power control can be realized.
And 4, step 4: setting on the premise of meeting the second and third steps
Figure BDA0002842349960000085
A simplified control method;
in step 4, the
Figure BDA0002842349960000086
As an auxiliary control variable, to simplify control, and to ensure maximum power transfer,
Figure BDA0002842349960000087
the maximum value is taken, and the setting is as follows:
Figure BDA0002842349960000088
if the setting constraint conditions are met, reactive power elimination of the double active converters can be achieved, power loss is reduced, transmission power of the double active converters is maximized, and control is simplified.
Fig. 7 is a schematic structural diagram illustrating an apparatus for reducing reactive power of a converter according to an embodiment of the present invention, as shown in fig. 6, the apparatus includes:
a constraint condition determining module 71, configured to determine a phase-shift duty ratio D according to a switching signal of the primary side switching tube1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure BDA0002842349960000089
Obtaining a constraint condition for limiting reactive power;
a maximum transfer power obtaining module 72, configured to control the phase shift duty ratio D of the switching signal of the primary side switching tube on the premise that the constraint condition is satisfied1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure BDA00028423499600000810
Obtaining the maximum transmission power of the converter;
and the device 73 for reducing the reactive power of the converter is used for controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arms again on the premise of maximizing the power transmission of the converter, so that the control step of reducing the reactive power of the converter is simplified.
Optionally, the constraint condition for limiting the reactive power is:
Figure BDA0002842349960000091
D2＝1+k(D1-1)
wherein k is n V1/V2N is the transformer transformation ratio, V1Is the primary side DC side voltage, V2Is the secondary side of the DC sideA voltage.
Optionally, the apparatus further comprises:
and the condition determining module is used for determining the condition for generating the reactive current.
Optionally, the condition determining module is further configured to:
when the middle point of the primary bridge arm outputs a voltage Vh1Or the midpoint voltage V of the secondary side bridge armh2And the transformer side inductor current iLWhen the polarities are different, reactive current can be generated on the primary side or the secondary side.
The specific implementation of each module, unit and sub-unit in the device for reducing the reactive power of the converter provided by the embodiment of the present disclosure may refer to the content in the method for reducing the reactive power of the converter, and is not described herein again.
It should be noted that although several modules, units and sub-units of the apparatus for action execution are mentioned in the above detailed description, such division is not mandatory. Indeed, the features and functionality of two or more modules, units and sub-units described above may be embodied in one module, unit and sub-unit, in accordance with embodiments of the present disclosure. Conversely, the features and functions of one module, unit and sub-unit described above may be further divided into embodiments by a plurality of modules, units and sub-units.
The basic principles of the present invention have been described above with reference to specific embodiments, but it should be noted that the advantages, effects, etc. mentioned in the present invention are only examples and are not limiting, and the advantages, effects, etc. must not be considered to be possessed by various embodiments of the present invention. Furthermore, the foregoing disclosure of specific details is for the purpose of illustration and description and is not intended to be limiting, since the invention is not limited to the specific details described above.
In the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts in the embodiments are referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions.
In the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts in the embodiments are referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The method and apparatus of the present invention may be implemented in a number of ways. For example, the methods and apparatus of the present invention may be implemented in software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustrative purposes only, and the steps of the method of the present invention are not limited to the order specifically described above unless specifically indicated otherwise. Furthermore, in some embodiments, the present invention may also be embodied as a program recorded in a recording medium, the program including machine-readable instructions for implementing a method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.
The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims (10)

1. A method of reducing converter reactive power, comprising:
according to the switching signal of the switching tube of the primary sideDuty cycle D1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure FDA0002842349950000011
Obtaining a constraint condition for limiting reactive power;
on the premise that the constraint condition is met, the phase-shifting duty ratio D of the switching signal of the primary side switching tube is controlled1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure FDA0002842349950000012
Obtaining the maximum transmission power of the converter;
and on the premise of maximizing the transmitted power of the converter, controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary bridge arms again, and simplifying the control step of reducing the reactive power of the converter.
2. The method according to claim 1, wherein the constraint condition for limiting reactive power is:
Figure FDA0002842349950000013
D2＝1+k(D1-1)
wherein k is n V1/V2N is the transformer transformation ratio, V1Is the primary side DC side voltage, V2Is the secondary side direct current side voltage.
3. The method of claim 1, wherein the phase-shift duty cycle D of the switching signal by controlling the primary side switching tube1And the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arm
Figure FDA0002842349950000014
Obtaining maximum transfer power of the converter, comprising:
the average power transfer over one switching cycle of the converter is expressed as:
Figure FDA0002842349950000015
wherein L is the inductance on the transformer side, fsIs the switching frequency. When it is satisfied with
Figure FDA0002842349950000016
In the case of constraint conditions, the maximum value of P is discussed in different cases, and the expression is as follows:
Figure FDA0002842349950000017
setting D1As a main control parameter, PmaxThe expression of (a) is:
Figure FDA0002842349950000018
when D is present1In (D)12And, 1) monotonic variation in power control is achieved, and D is set so that P has a maximum value1Comprises the following steps:
Figure FDA0002842349950000019
4. the method according to claim 3, wherein the method according to claim 1 is characterized in that the method is used for controlling the term-shift duty ratio corresponding to the term-shift angle of the voltage between the middle points of the primary and secondary bridge arms again on the premise of maximizing the power transferred by the converter, so as to simplify the control step of reducing the reactive power of the converter, and comprises the following steps:
Figure FDA0002842349950000021
5. the method of claim 1, wherein the duty cycle D is shifted according to the switching signal of the primary switching tube1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure FDA0002842349950000022
Before obtaining the constraint condition for limiting the reactive power, the method further comprises:
the conditions for generating reactive current are determined.
6. The method according to claim 5, wherein the condition for determining the generation of reactive current is:
when the middle point of the primary bridge arm outputs a voltage Vh1Or the midpoint voltage V of the secondary side bridge armh2And the transformer side inductor current iLWhen the polarities are different, reactive current can be generated on the primary side or the secondary side.
7. An apparatus for reducing converter reactive power, comprising:
a constraint condition determining module for determining a shift duty ratio D according to the switching signal of the primary side switching tube1Phase shift duty ratio D of switching signal of secondary side switching tube2Item shifting duty ratio corresponding to item shifting angle of voltage between middle points of original secondary side bridge arms
Figure FDA0002842349950000023
Obtaining a constraint condition for limiting reactive power;
a maximum transfer power acquisition module for controlling the phase shift duty ratio D of the switching signal of the primary side switching tube on the premise that the constraint condition is satisfied1And the item shift corresponding to the item shift angle of the voltage between the middle points of the original secondary side bridge armDuty cycle
Figure FDA0002842349950000024
Obtaining the maximum transmission power of the converter;
the device for reducing the reactive power of the converter is used for controlling the item shifting duty ratio corresponding to the item shifting angle of the voltage between the middle points of the original secondary side bridge arms again on the premise of maximizing the power transmission of the converter, and simplifies the control steps for reducing the reactive power of the converter.
8. The apparatus of claim 7, wherein the constraint condition for limiting reactive power is:
Figure FDA0002842349950000025
D2＝1+k(D1-1)
wherein k is n V1/V2N is the transformer transformation ratio, V1Is the primary side DC side voltage, V2Is the secondary side direct current side voltage.
9. The apparatus of claim 7, further comprising:
and the condition determining module is used for determining the condition for generating the reactive current.
10. The apparatus of claim 9, wherein the condition determining module is further configured to:
when the middle point of the primary bridge arm outputs a voltage Vh1Or the midpoint voltage V of the secondary side bridge armh2And the transformer side inductor current iLWhen the polarities are different, reactive current can be generated on the primary side or the secondary side.
CN202011496625.3A 2020-12-17 2020-12-17 Method and device for reducing reactive power of converter Active CN112701917B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011496625.3A CN112701917B (en) 2020-12-17 2020-12-17 Method and device for reducing reactive power of converter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011496625.3A CN112701917B (en) 2020-12-17 2020-12-17 Method and device for reducing reactive power of converter

Publications (2)

Publication Number Publication Date
CN112701917A true CN112701917A (en) 2021-04-23
CN112701917B CN112701917B (en) 2024-01-23

Family

ID=75508854

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011496625.3A Active CN112701917B (en) 2020-12-17 2020-12-17 Method and device for reducing reactive power of converter

Country Status (1)

Country Link
CN (1) CN112701917B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06217462A (en) * 1993-01-12 1994-08-05 Hitachi Ltd Starting system for reactive power controller
CN110401350A (en) * 2019-07-01 2019-11-01 中南大学 The phase-shifting control method of the full-load range ZVS of double active full-bridge bidirectional DC-DC converters
CN110535350A (en) * 2019-09-07 2019-12-03 陕西航空电气有限责任公司 A method of reducing double active full-bridge DC-DC converter circulation loss
CN110572041A (en) * 2019-09-29 2019-12-13 西安理工大学 Bilateral PWM (pulse-Width modulation) plus phase shift control method of double-active full-bridge converter
CN111478600A (en) * 2020-04-07 2020-07-31 北京理工大学 Control method for double-active bridge type single-stage AC-DC converter

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06217462A (en) * 1993-01-12 1994-08-05 Hitachi Ltd Starting system for reactive power controller
CN110401350A (en) * 2019-07-01 2019-11-01 中南大学 The phase-shifting control method of the full-load range ZVS of double active full-bridge bidirectional DC-DC converters
CN110535350A (en) * 2019-09-07 2019-12-03 陕西航空电气有限责任公司 A method of reducing double active full-bridge DC-DC converter circulation loss
CN110572041A (en) * 2019-09-29 2019-12-13 西安理工大学 Bilateral PWM (pulse-Width modulation) plus phase shift control method of double-active full-bridge converter
CN111478600A (en) * 2020-04-07 2020-07-31 北京理工大学 Control method for double-active bridge type single-stage AC-DC converter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
谷泓杰等: ""基于三重移相的双向全桥DC-DC功率特性分析"", 《中国电力》 *

Also Published As

Publication number Publication date
CN112701917B (en) 2024-01-23

Similar Documents

Publication Publication Date Title
CN109889047B (en) Two-stage DC-DC converter suitable for wide input and output voltage range
CN108988451A (en) Isolation type bidirectional charger control method and control circuit
CN103944397B (en) Boost type isolated DC/DC converter and control method thereof
CN102904454A (en) Efficient insulation DC (direct-current) converter system in photovoltaic power generation system
CN111431415B (en) High-boost isolated DC converter with parallel input and series output
CN105591559A (en) Multi-port converter based on high-frequency inversion
CN208939829U (en) A kind of controlled resonant converter
CN108988646B (en) DAB (digital audio broadcasting) optimization control method with voltage transmission ratio larger than 1 under zero-voltage switch
CN114285286A (en) Single-stage zero-current switch full-bridge boost direct current converter and control method thereof
CN113517817A (en) Three-level bidirectional full-bridge LLCLC multi-resonant converter topology
CN109842299A (en) Combined DC transformation system and its control method
CN111342664A (en) Integrated DC-DC converter and control method thereof
CN103606953A (en) Single-stage boosting three-phase flyback inverter for solar energy grid-connected power generation
CN109878352A (en) A kind of photovoltaic charging system and method
CN104779807A (en) LLC resonance transducer applied to distributed power source
CN112701917B (en) Method and device for reducing reactive power of converter
CN116388533A (en) Optimization method of DAB converter current stress under full load range ZVS
CN112436747B (en) Electric drive system, power assembly and electric automobile
CN114312382A (en) System topology suitable for wired and wireless integrated charging pile of electric automobile
CN113746345A (en) Double-active-bridge converter based on multi-winding high-frequency transformer and control method
CN113794381A (en) SCDAB-CLLLC composite direct current transformer with wide voltage regulation range and control method thereof
CN111669057A (en) DC boost converter and control method thereof
CN113507212B (en) Double-active-bridge DC-DC converter based on three-winding coupling inductor and power control method
CN110829876B (en) Topological structure of single-phase solid-state transformer
CN117294149B (en) Pulse modulation system of improved unidirectional direct-current series resonant 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
GR01 Patent grant
GR01 Patent grant