CN112054685A - Electric energy router and control method thereof - Google Patents

Electric energy router and control method thereof Download PDF

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Publication number
CN112054685A
CN112054685A CN202010817416.8A CN202010817416A CN112054685A CN 112054685 A CN112054685 A CN 112054685A CN 202010817416 A CN202010817416 A CN 202010817416A CN 112054685 A CN112054685 A CN 112054685A
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China
Prior art keywords
voltage
turn
conversion unit
electric energy
stage conversion
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CN202010817416.8A
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Chinese (zh)
Inventor
查鲲鹏
燕翚
王轩
朱宁辉
张加林
付永生
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.)
State Grid Corp of China SGCC
State Grid Shanghai Electric Power Co Ltd
China EPRI Science and Technology Co Ltd
China EPRI Electric Power Engineering Co Ltd
State Grid Electric Power Research Institute
Original Assignee
State Grid Corp of China SGCC
State Grid Shanghai Electric Power Co Ltd
China EPRI Science and Technology Co Ltd
China EPRI Electric Power Engineering Co Ltd
State Grid Electric Power Research Institute
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Application filed by State Grid Corp of China SGCC, State Grid Shanghai Electric Power Co Ltd, China EPRI Science and Technology Co Ltd, China EPRI Electric Power Engineering Co Ltd, State Grid Electric Power Research Institute filed Critical State Grid Corp of China SGCC
Priority to CN202010817416.8A priority Critical patent/CN112054685A/en
Publication of CN112054685A publication Critical patent/CN112054685A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—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
    • H02M3/3353—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 at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
    • 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
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • H02M1/15—Arrangements for reducing ripples from dc input or output using active elements
    • 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
    • H02M1/0054—Transistor switching losses
    • 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

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

Abstract

The invention provides an electric energy router and a control method thereof, the electric energy router comprises a plurality of power modules, each power module comprises a preceding stage conversion unit and a subsequent stage conversion unit which are mutually connected, the preceding stage conversion units of all the power modules are connected in series to form a high-voltage port of the electric energy router, and the subsequent stage conversion units of all the power modules are connected in series and/or in parallel to form a low-voltage port of the electric energy router. The power density is large, the loss of the turn-off device is low, the output voltage range is wide, the output ripple is small, and the structure is compact.

Description

Electric energy router and control method thereof
Technical Field
The invention relates to the technical field of electric energy routing, in particular to an electric energy router and a control method thereof.
Background
An energy router (energy router) is a core device which takes electric energy as a core, can collect and manage electricity, heat, cold, fuel gas and other forms of energy, has the functions of flexible energy conversion, transformation, transmission and routing, realizes the fusion of an energy physical system and an information system, and supports an energy internet. The electric energy router is a basic form of the energy router and can be independently used. The electric energy is used as a control object, the electric energy control system is provided with two or more electric energy interfaces, has flexible conversion, transmission and routing functions among electric energy with different electric parameters, and realizes the fusion of an electric physical system and an information system.
The energy router can support a wide area energy network to realize interconnection; the system can be used for energy production of large-scale hydraulic power plants, wind power plants and photovoltaic power stations, can also be used for energy production of parks, buildings and users, realizes the instant cooperation of energy producers, network operators and decentralized power generation with the users, and provides ubiquitous energy service.
In the existing electric energy router, the loss of a power conversion link is large, the output of a low-voltage direct current output link is unstable under light load, the direct current voltage regulation range of a low-voltage port is small, and the adaptability is poor.
Disclosure of Invention
In order to overcome the defect of poor adaptability of the electric energy router in the prior art, the invention provides the electric energy router which comprises a plurality of power modules, wherein each power module comprises a preceding stage conversion unit and a subsequent stage conversion unit which are mutually connected, the preceding stage conversion units of all the power modules are connected in series to form a high-voltage port of the electric energy router, and the subsequent stage conversion units of all the power modules are connected in series and/or in parallel to form a low-voltage port of the electric energy router.
The power module further comprises a direct current support capacitor (13), and the direct current support capacitor (13) is connected between the front-stage conversion unit and the rear-stage conversion unit in series.
The pre-stage conversion unit comprises a first turn-off device (1), a second turn-off device (2), a third turn-off device (3), a fourth turn-off device (4), a fifth turn-off device (5), a sixth turn-off device (6), a seventh turn-off device (7), an eighth turn-off device (8), a high-voltage side capacitor (9), a resonance inductor (10), a high-frequency transformer (11) and a resonance capacitor (12), which are connected with diodes in anti-parallel;
the first turn-off device (1) and the second turn-off device (2) are connected in series to form a first bridge arm, the third turn-off device (3) and the fourth turn-off device (4) are connected in series to form a second bridge arm, and the first bridge arm, the second bridge arm and the high-voltage side capacitor (9) are connected in parallel;
the fifth turn-off device (5) and the sixth turn-off device (6) are connected in series to form a third bridge arm, the seventh turn-off device (7) and the eighth turn-off device (8) are connected in series to form a fourth bridge arm, and the third bridge arm, the fourth bridge arm and the direct-current support capacitor (13) are connected in parallel;
one end of the resonant inductor (10) is connected with the midpoint of the first bridge arm, the other end of the resonant inductor is connected with one end of a primary winding of the high-frequency transformer (11), and the other end of the primary winding of the high-frequency transformer (11) is connected with the midpoint of the second bridge arm through the resonant capacitor (12); one end of the secondary winding of the high-frequency transformer (11) is connected with the midpoint of the third bridge arm, and the other end of the secondary winding of the high-frequency transformer is connected with the midpoint of the fourth bridge arm.
The post-stage conversion unit comprises a fourteenth turn-off device (14), a fifteenth turn-off device (15), a sixteenth turn-off device (16), a seventeenth turn-off device (17), a filter inductor (18), a filter inductor (19) and a low-voltage side capacitor (20), wherein the fourteenth turn-off device, the fifteenth turn-off device, the sixteenth turn-off device, the seventeenth turn-off device, the filter inductor (18), the filter inductor (19) and the;
the fourteenth turn-off device (14) and the fifteenth turn-off device (15) are connected in series to form a fifth bridge arm, the sixteenth turn-off device (16) and the seventeenth turn-off device (17) are connected in series to form a sixth bridge arm, and the fifth bridge arm, the sixth bridge arm and the low-voltage side capacitor (20) are connected in parallel;
one end of the filter inductor (18) is connected with the midpoint of the fifth bridge arm, one end of the filter inductor (19) is connected with the midpoint of the sixth bridge arm, the other end of the filter inductor (18) is connected with the other end of the filter inductor (19) and serves as an anode port of the rear-stage conversion unit, one end of the low-voltage side capacitor (20) is connected with the anode port, and the other end of the low-voltage side capacitor is connected with a cathode port of the rear-stage conversion unit.
The voltage gain of the preceding conversion unit is determined according to the following formula:
Figure BDA0002633214250000021
in the formula, M (f)s *And Q) is the voltage gain of the preceding stage conversion unit; f. ofs *Is a per unit switching frequency, and
Figure BDA0002633214250000022
fsfor the switching frequency of the preceding conversion unit, fr1Is the resonance frequency of the resonance inductor (10) and the resonance capacitor (12), and
Figure BDA0002633214250000023
Lris the inductance value of the resonant inductor (10), CrIs a resonance capacitor (12)The capacitance value of (a); q is a quality factor of the resonant inductor (10) and the high-frequency transformer (11), and
Figure BDA0002633214250000024
Mmaxis the maximum voltage gain of the preceding conversion unit, K is the ratio of resonance inductances, and K is Lr/Lm，LmThe value of the exciting inductance of the high-frequency transformer (11).
The high-voltage port of the electric energy router is connected to the high-voltage direct-current system through the positive direct-current bus and the negative direct-current bus direct-current system, and the low-voltage port of the electric energy router is connected to the low-voltage direct-current system through the positive direct-current bus and the negative direct-current bus direct-current system.
When the electric energy router is connected to a symmetrical monopole direct current system, the midpoint of the high-voltage port or the low-voltage port of the electric energy router is grounded;
when the electric energy router is connected into the unidirectional bias direct current system, the positive direct current bus or the negative direct current bus connected with the electric energy router is grounded.
On the other hand, the invention also provides a control method of the electric energy router, which comprises the following steps:
the method comprises the following steps that the preceding stage conversion units of all power modules are connected in series to form a high-voltage port of the electric energy router, and the subsequent stage conversion units of all the power modules are connected in series and/or in parallel to form a low-voltage port of the electric energy router;
determining the switching frequency and the duty ratio of a preceding stage conversion unit in the power module based on the direct current detection value of a low-voltage port in the electric energy router;
determining the duty ratio of a post-stage conversion unit in the power module based on a direct-current voltage detection value and a direct-current voltage instruction value of a low-voltage port in the electric energy router;
and controlling the output voltage of the electric energy router based on the switching frequency and the duty ratio of the preceding stage conversion unit and the duty ratio of the subsequent stage conversion unit.
The method for determining the switching frequency and the duty ratio of the preceding stage conversion unit in the power module based on the direct current detection value of the low-voltage port in the electric energy router comprises the following steps:
when the direct current detection value of the low-voltage port is 0, controlling the pre-stage conversion unit to be in a pulse width modulation mode, and determining the duty ratio of the pre-stage conversion unit based on the pulse width modulation mode;
when the direct current detection value of the low-voltage port is larger than or equal to a preset current threshold value, controlling the pre-stage conversion unit to be in a pulse frequency modulation mode, and determining the switching frequency of the pre-stage conversion unit based on the pulse frequency modulation mode;
and when the direct current detection value of the low-voltage port is larger than 0 and smaller than a preset current threshold value, controlling the pre-stage conversion unit to be in a mixed mode of a pulse width modulation mode and a pulse frequency modulation mode, and determining the switching frequency and the duty ratio of the pre-stage conversion unit based on the mixed mode.
The determining the duty ratio of the post-stage conversion unit in the power module based on the direct-current voltage detection value and the direct-current voltage instruction value of the low-voltage port in the electric energy router comprises the following steps:
the difference value of the direct current voltage instruction value and the direct current voltage detection value of the low-voltage port is subjected to proportional integral and amplitude limiting control in sequence to obtain a direct current instruction value of the low-voltage port;
and (3) sequentially carrying out proportional integral and amplitude limiting control on the difference value between the direct current instruction value and the direct current detection value of the low-voltage port to obtain the duty ratio of a post-stage conversion unit in the power module.
The technical scheme provided by the invention has the following beneficial effects:
the electric energy router provided by the invention comprises a plurality of power modules, wherein each power module comprises a preceding stage conversion unit and a subsequent stage conversion unit which are connected with each other, the preceding stage conversion units of all the power modules are connected in series to form a high-voltage port of the electric energy router, and the subsequent stage conversion units of all the power modules are connected in series and/or in parallel to form a low-voltage port of the electric energy router;
the power module is provided with the resonant inductor and the resonant capacitor, namely the power module adopts a soft switching technology, so that the loss is greatly reduced, the working efficiency of the electric energy router is improved, and the high-efficiency operation of the electric energy router is realized;
the voltage limiting and current limiting functions of the electric energy router are realized through the post-stage conversion unit, and the electric isolation is realized through the high-frequency transformer (11), so that the safety is high;
when the direct current detection value of the low-voltage port is 0, the pre-stage conversion unit is controlled to be in a pulse width modulation mode, and the duty ratio of the pre-stage conversion unit is determined based on the pulse width modulation mode, namely the direct current output link of the low-voltage port is stable in output under light load, and the modulation signals of the fifth bridge arm and the sixth bridge arm have a 180-degree difference, so that the output voltage ripple can be greatly reduced, extra filtering is not needed, the inductance values of a filter inductor (18) and a filter inductor (19) are reduced, and the cost and the volume of the electric energy router are further reduced;
the pre-stage conversion unit adopts the mixed control of the switching frequency and the duty ratio, the control mode avoids the problem of overhigh switching frequency under the conditions of no load and light load, is beneficial to the stability of output voltage under the condition of light load, expands the voltage regulation and control range of the post-stage conversion unit, has the characteristics of simple realization and smooth switching of a circuit under different modes, and ensures the reliability of the electric energy router;
the post-stage conversion unit adopts a phase-staggered parallel connection mode, so that the power transmission capacity of the electric energy router is improved, the output ripple is reduced, and the volume is reduced;
the electric energy router provided by the invention can support the bidirectional flow of power, namely, the conversion from high-voltage direct current to low-voltage direct current can be realized, the conversion from low-voltage direct current to high-voltage direct current can be realized, the power density is high, the loss of a turn-off device is low, the output voltage range is wide, the output ripple wave is small, the structure is compact, and multi-port routing is realized.
Drawings
Fig. 1 is a diagram of a power router in an embodiment of the invention;
FIG. 2 is a block diagram of a power module in an embodiment of the invention;
fig. 3 is a flowchart of a power router control method according to an embodiment of the present invention;
fig. 4 is a block diagram of a control strategy of a subsequent transform unit in an embodiment of the invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Example 1
An embodiment 1 of the present invention provides an electric energy router, as shown in fig. 1, including a plurality of power modules, where each power module includes a preceding stage conversion unit and a succeeding stage conversion unit that are connected to each other, the preceding stage conversion units of all the power modules are connected in series to form a high voltage port of the electric energy router, and the succeeding stage conversion units of all the power modules are connected in series and/or in parallel to form a low voltage port of the electric energy router.
In embodiment 1 of the present invention, the power module has a two-port structure, and the high-voltage ports of the power modules are connected in series to form a high-voltage port of the electric energy router, and the dc voltage of the electric energy router is U1(ii) a The low-voltage ports of the power modules are connected in parallel to form the low-voltage port of the electric energy router, and the direct-current voltage of the low-voltage port is U2. When the other ends of the power modules are connected in parallel, the power modules can be grouped, so that a plurality of low-voltage ports with the same or different output voltages can be constructed, in embodiment 1 of the invention, the other ends of the power modules form two low-voltage ports with different output voltages, namely, U in fig. 12And U3。
As shown in fig. 2, the power module further includes a dc support capacitor 13, and the dc support capacitor 13 is connected in series between the preceding stage conversion unit and the succeeding stage conversion unit.
The power module in embodiment 1 of the present invention is a two-stage series structure based on a turn-off device (e.g., SiC MOSFET, IGBT, MOSFET, etc.), and can achieve light weight and high efficiency of the power module on the premise of satisfying high power output.
The pre-stage conversion unit comprises a turn-off device 1, a turn-off device 2, a turn-off device 3, a turn-off device 4, a turn-off device 5, a turn-off device 6, a turn-off device 7, a turn-off device 8, a high-voltage side capacitor 9, a resonance inductor 10, a high-frequency transformer 11 and a resonance capacitor 12 which are connected with the diode in anti-parallel;
the turn-off device 1 and the turn-off device 2 are connected in series to form a first bridge arm, the turn-off device 3 and the turn-off device 4 are connected in series to form a second bridge arm, and the first bridge arm, the second bridge arm and the high-voltage side capacitor 9 are connected in parallel;
the turn-off device 5 and the turn-off device 6 are connected in series to form a third bridge arm, the turn-off device 7 and the turn-off device 8 are connected in series to form a fourth bridge arm, and the third bridge arm, the fourth bridge arm and the direct current support capacitor 13 are connected in parallel;
one end of a resonant inductor 10 is connected with the midpoint of the first bridge arm, the other end of the resonant inductor is connected with one end of a primary winding of a high-frequency transformer 11, and the other end of the primary winding of the high-frequency transformer 11 is connected with the midpoint of the second bridge arm through a resonant capacitor 12; one end of the secondary winding of the high-frequency transformer 11 is connected with the midpoint of the third bridge arm, and the other end of the secondary winding is connected with the midpoint of the fourth bridge arm. The series sequence of the resonant inductor 10, the primary winding of the high-frequency transformer 11 and the resonant capacitor 12 can be adjusted at will.
The rear-stage conversion unit comprises a fourteenth turn-off device 14, a fifteenth turn-off device 15, a sixteenth turn-off device 16, a seventeenth turn-off device 17, a filter inductor 18, a filter inductor 19 and a low-voltage side capacitor 20 which are connected with the diodes in anti-parallel;
the fourteenth turn-off device 14 and the fifteenth turn-off device 15 are connected in series to form a fifth bridge arm, the sixteenth turn-off device 16 and the seventeenth turn-off device 17 are connected in series to form a sixth bridge arm, and the fifth bridge arm, the sixth bridge arm and the low-voltage side capacitor 20 are connected in parallel;
one end of the filter inductor 18 is connected with the midpoint of the fifth bridge arm, one end of the filter inductor 19 is connected with the midpoint of the sixth bridge arm, the other end of the filter inductor 18 is connected with the other end of the filter inductor 19 and serves as a positive electrode port of the rear-stage conversion unit, one end of the low-voltage side capacitor 20 is connected with the positive electrode port, and the other end of the low-voltage side capacitor is connected with a negative electrode port of the rear-stage conversion unit.
The turn-off device in the embodiment of the invention comprises a SiC MOSFET or IGBT, MOSFET and other devices.
The post-stage conversion unit realizes the organic combination of Buck and Boost circuits and has the characteristic of bidirectional flow of direct current power. When the upper tube MOSFET, the lower tube diode and the inductor form a Buck circuit, power flows from the high-voltage port to the low-voltage port; when the upper tube diode, the lower tube MOSFET and the inductor form a Boost circuit, power flows from the low-voltage port to the high-voltage port.
The difference between the modulation signals of the fifth bridge arm and the sixth bridge arm is 180 degrees, so that the output voltage ripple can be greatly reduced, additional filtering is not needed, the inductance values of the filter inductor 18 and the filter inductor 19 are reduced, and the size and the floor area of the electric energy router are further reduced.
In embodiment 1 of the present invention, the turn-off device may be a novel device such as SiC or GaN, and the loss is further reduced compared to a Si-based device.
The voltage gain of the preceding conversion unit is determined according to the following formula:
Figure BDA0002633214250000061
in the formula, M (f)s *And Q) is the voltage gain of the preceding stage conversion unit; f. ofs *Is a per unit switching frequency, and
Figure BDA0002633214250000062
fsfor the switching frequency of the preceding conversion unit, fr1Is the resonant frequency of the resonant inductor 10 and the resonant capacitor 12, and
Figure BDA0002633214250000063
Lris the inductance value, C, of the resonant inductor 10rIs the capacitance value of the resonant capacitor 12; q is a quality factor of the resonant inductor 10 and the high-frequency transformer 11, and
Figure BDA0002633214250000064
Mmaxis the maximum voltage gain of the preceding conversion unit, K is the ratio of resonance inductances, and K is Lr/Lm，LmIs the value of the field inductance of the high-frequency transformer 11. L ism、CrAnd tuning of load condition determinationThe frequency of vibration is noted as fr2When the load is heavy, the resonant frequency will increase,
Figure BDA0002633214250000065
obviously, fr2<fr1. When K is a fixed value, the smaller Q, the steeper the curve becomes, the larger the gain becomes, but the frequency adjustment range becomes wider, which is disadvantageous in the operation of the magnetic element. For a resonant circuit, to achieve zero voltage switching, the minimum switching frequency should not be lower than f to make the network impedance appear inductiver2。
The high-voltage port of the electric energy router is connected to the high-voltage direct-current system through the positive direct-current bus and the negative direct-current bus direct-current system, and the low-voltage port of the electric energy router is connected to the low-voltage direct-current system through the positive direct-current bus and the negative direct-current bus direct-current system.
When the electric energy router is connected into a symmetrical monopole direct current system (such as +/-10 kV, +/-20 kV and the like), the midpoint of a high-voltage port or a low-voltage port of the electric energy router is grounded;
when the electric energy router is connected into a unidirectional bias direct current system (such as +10kV, -10kV and the like), the positive direct current bus or the negative direct current bus connected with the electric energy router is grounded.
The power modules can be grouped at the low-voltage side, and a positive-negative symmetrical low-voltage direct-current system (such as +/-375V) can be constructed when the same modules are equally divided into two groups, and the middle point is grounded; the direct current voltage of each group of low-voltage ports can be controlled respectively, and each group of voltage is input/output in a wide range, for example, the direct current voltage can be set arbitrarily within 100V-1000V according to the load condition.
Example 2
Embodiment 2 of the present invention provides a method for controlling an electric energy router, where a specific flowchart is shown in fig. 3, and the specific process is as follows:
s101: the method comprises the following steps that the preceding stage conversion units of all power modules are connected in series to form a high-voltage port of the electric energy router, and the subsequent stage conversion units of all the power modules are connected in series and/or in parallel to form a low-voltage port of the electric energy router;
s102: determining the switching frequency and the duty ratio of a preceding stage conversion unit in the power module based on the direct current detection value of a low-voltage port in the electric energy router;
s103: determining the duty ratio of a post-stage conversion unit in the power module based on a direct-current voltage detection value and a direct-current voltage instruction value of a low-voltage port in the electric energy router;
s104: and controlling the output voltage of the electric energy router based on the switching frequency and the duty ratio of the preceding stage conversion unit and the duty ratio of the subsequent stage conversion unit.
The method for determining the switching frequency and the duty ratio of a preceding stage conversion unit in a power module based on the direct current detection value of a low-voltage port in an electric energy router comprises the following steps:
when the direct current detection value of the low-voltage port is 0, controlling the preceding stage conversion unit to be in a pulse width modulation mode (namely PFM mode), and determining the duty ratio of the preceding stage conversion unit based on the pulse width modulation mode; the output voltage is adjusted by changing the switching frequency of the turn-off device in the PFM mode;
when the direct current detection value of the low-voltage port is larger than or equal to a preset current threshold value, controlling the pre-stage conversion unit to be in a pulse frequency modulation mode (namely a PWM mode), and determining the switching frequency of the pre-stage conversion unit based on the pulse frequency modulation mode; under the PWM mode, the duty ratio of the turn-off device is adjusted according to the load state, and the voltage regulation range is expanded;
when the direct current detection value of the low-voltage port is larger than 0 and smaller than a preset current threshold value, the pre-stage conversion unit is controlled to be in a mixed mode of a pulse width modulation mode (namely a PWM mode) and a pulse frequency modulation mode (namely a PFM mode), and the switching frequency and the duty ratio of the pre-stage conversion unit are determined based on the mixed mode.
Determining the duty ratio of the post-stage conversion unit in the power module based on the direct-current voltage detection value and the direct-current voltage instruction value of the low-voltage port in the electric energy router, as shown in fig. 4, u in fig. 42 *Is a DC voltage command value, u, of the low-voltage port2Is the DC voltage detection value of a low-voltage port, PI is a proportional-integral link, IL *Is a DC current command value of the low-voltage port, ILDC current sense for low voltage portMeasured value, D2Specifically, the duty ratio of a post-stage conversion unit in a power module includes:
the difference value of the direct current voltage instruction value and the direct current voltage detection value of the low-voltage port is subjected to proportional integral and amplitude limiting control in sequence to obtain a direct current instruction value of the low-voltage port, namely u2 *And u2The difference value is subjected to proportional integral and amplitude limiting control in sequence to obtain IL *；
The difference value of the direct current instruction value and the direct current detection value of the low-voltage port is subjected to proportional integral and amplitude limiting control in sequence to obtain the duty ratio of a post-stage conversion unit in the power module, namely IL *And ILThe difference value is subjected to proportional integral and amplitude limiting control in sequence to obtain D2. When the DC current command value I of the low-voltage portL *When the current is larger than 0, the tide of the electric energy router flows to the low-voltage port from the high-voltage port, and when the direct current instruction value I of the low-voltage portL *When the current is less than 0, the tide of the electric energy router flows to the high-voltage port from the low-voltage port.
For convenience of description, each part of the above apparatus is separately described as being functionally divided into various modules or units. Of course, the functionality of the various modules or units may be implemented in the same one or more pieces of software or hardware when implementing the present application.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and a person of ordinary skill in the art can make modifications or equivalent substitutions to the specific embodiments of the present invention with reference to the above embodiments, and any modifications or equivalent substitutions which do not depart from the spirit and scope of the present invention are within the protection scope of the present invention as claimed in the appended claims.

Claims (10)

1. An electrical energy router comprising a plurality of power modules;
each power module comprises a preceding stage conversion unit and a subsequent stage conversion unit which are mutually connected, the preceding stage conversion units of all the power modules are connected in series to form a high-voltage port of the electric energy router, and the subsequent stage conversion units of all the power modules are connected in series and/or in parallel to form a low-voltage port of the electric energy router.
2. The electrical energy router of claim 1, wherein the power module further comprises a DC support capacitor (13), the DC support capacitor (13) being connected in parallel between the preceding stage and the succeeding stage.
3. The electrical energy router according to claim 2, wherein the preceding stage transformation unit comprises a first turn-off capable device (1), a second turn-off capable device (2), a third turn-off capable device (3), a fourth turn-off capable device (4), a fifth turn-off capable device (5), a sixth turn-off capable device (6), a seventh turn-off capable device (7), an eighth turn-off capable device (8), a high-voltage side capacitor (9), a resonance inductor (10), a high-frequency transformer (11), and a resonance capacitor (12) in anti-parallel with the diodes;
the first turn-off device (1) and the second turn-off device (2) are connected in series to form a first bridge arm, the third turn-off device (3) and the fourth turn-off device (4) are connected in series to form a second bridge arm, and the first bridge arm, the second bridge arm and the high-voltage side capacitor (9) are connected in parallel;
the fifth turn-off device (5) and the sixth turn-off device (6) are connected in series to form a third bridge arm, the seventh turn-off device (7) and the eighth turn-off device (8) are connected in series to form a fourth bridge arm, and the third bridge arm, the fourth bridge arm and the direct-current support capacitor (13) are connected in parallel;
one end of the resonant inductor (10) is connected with the midpoint of the first bridge arm, the other end of the resonant inductor is connected with one end of a primary winding of the high-frequency transformer (11), and the other end of the primary winding of the high-frequency transformer (11) is connected with the midpoint of the second bridge arm through the resonant capacitor (12); one end of the secondary winding of the high-frequency transformer (11) is connected with the midpoint of the third bridge arm, and the other end of the secondary winding of the high-frequency transformer is connected with the midpoint of the fourth bridge arm.
4. The electrical energy router of claim 2, wherein the post-stage conversion unit comprises a fourteenth turn-off device (14), a fifteenth turn-off device (15), a sixteenth turn-off device (16), a seventeenth turn-off device (17), a filter inductor (18), a filter inductor (19) and a low-side capacitor (20) in anti-parallel with the diode;
the fourteenth turn-off device (14) and the fifteenth turn-off device (15) are connected in series to form a fifth bridge arm, the sixteenth turn-off device (16) and the seventeenth turn-off device (17) are connected in series to form a sixth bridge arm, and the fifth bridge arm, the sixth bridge arm and the low-voltage side capacitor (20) are connected in parallel;
one end of the filter inductor (18) is connected with the midpoint of the fifth bridge arm, one end of the filter inductor (19) is connected with the midpoint of the sixth bridge arm, the other end of the filter inductor (18) is connected with the other end of the filter inductor (19) and serves as an anode port of the rear-stage conversion unit, one end of the low-voltage side capacitor (20) is connected with the anode port, and the other end of the low-voltage side capacitor is connected with a cathode port of the rear-stage conversion unit.
5. The power router of claim 3 wherein the voltage gain of the prior stage transformation unit is determined by:
Figure FDA0002633214240000021
in the formula, M (f)s *And Q) is the voltage gain of the preceding stage conversion unit; f. ofs *Is a per unit switching frequency, and
Figure FDA0002633214240000022
fsfor the switching frequency of the preceding conversion unit, fr1Is the resonance frequency of the resonance inductor (10) and the resonance capacitor (12), and
Figure FDA0002633214240000023
Lris the inductance value of the resonant inductor (10), CrIs the capacitance value of the resonance capacitor (12); q is a quality factor of the resonant inductor (10) and the high-frequency transformer (11), and
Figure FDA0002633214240000024
Mmaxis the maximum voltage gain of the preceding conversion unit, K is the ratio of resonance inductances, and K is Lr/Lm，LmThe value of the exciting inductance of the high-frequency transformer (11).
6. The electric energy router according to claim 1, wherein the high voltage port of the electric energy router is connected to the high voltage direct current system through a positive direct current bus and a negative direct current bus direct current system, and the low voltage port of the electric energy router is connected to the low voltage direct current system through a positive direct current bus and a negative direct current bus direct current system.
7. The power router of claim 6, wherein when the power router is connected to a symmetrical unipolar DC system, a midpoint of a high voltage port or a low voltage port of the power router is grounded;
when the electric energy router is connected into the unidirectional bias direct current system, the positive direct current bus or the negative direct current bus connected with the electric energy router is grounded.
8. A control method of an electric energy router is characterized by comprising the following steps:
the method comprises the following steps that the preceding stage conversion units of all power modules are connected in series to form a high-voltage port of the electric energy router, and the subsequent stage conversion units of all the power modules are connected in series and/or in parallel to form a low-voltage port of the electric energy router;
determining the switching frequency and the duty ratio of a preceding stage conversion unit in the power module based on the direct current detection value of a low-voltage port in the electric energy router;
determining the duty ratio of a post-stage conversion unit in the power module based on a direct-current voltage detection value and a direct-current voltage instruction value of a low-voltage port in the electric energy router;
and controlling the output voltage of the electric energy router based on the switching frequency and the duty ratio of the preceding stage conversion unit and the duty ratio of the subsequent stage conversion unit.
9. The control method of the electric energy router as claimed in claim 8, wherein the determining the switching frequency and the duty ratio of the pre-stage conversion unit in the power module based on the direct current detection value of the low-voltage port in the electric energy router comprises:
when the direct current detection value of the low-voltage port is 0, controlling the pre-stage conversion unit to be in a pulse width modulation mode, and determining the duty ratio of the pre-stage conversion unit based on the pulse width modulation mode;
when the direct current detection value of the low-voltage port is larger than or equal to a preset current threshold value, controlling the pre-stage conversion unit to be in a pulse frequency modulation mode, and determining the switching frequency of the pre-stage conversion unit based on the pulse frequency modulation mode;
and when the direct current detection value of the low-voltage port is larger than 0 and smaller than a preset current threshold value, controlling the pre-stage conversion unit to be in a mixed mode of a pulse width modulation mode and a pulse frequency modulation mode, and determining the switching frequency and the duty ratio of the pre-stage conversion unit based on the mixed mode.
10. The control method of the electric energy router according to claim 8, wherein the determining the duty ratio of the post-stage conversion unit in the power module based on the direct-current voltage detection value and the direct-current voltage command value of the low-voltage port in the electric energy router comprises:
the difference value of the direct current voltage instruction value and the direct current voltage detection value of the low-voltage port is subjected to proportional integral and amplitude limiting control in sequence to obtain a direct current instruction value of the low-voltage port;
and (3) sequentially carrying out proportional integral and amplitude limiting control on the difference value between the direct current instruction value and the direct current detection value of the low-voltage port to obtain the duty ratio of a post-stage conversion unit in the power module.
CN202010817416.8A 2020-08-14 2020-08-14 Electric energy router and control method thereof Pending CN112054685A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115037120A (en) * 2022-06-09 2022-09-09 合肥工业大学 Two-stage energy router system and method based on modular multi-port converter
WO2023103352A1 (en) * 2021-12-09 2023-06-15 南方电网电力科技股份有限公司 Direct-current power collection system of wave energy power generation device, and control method and system therefor

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023103352A1 (en) * 2021-12-09 2023-06-15 南方电网电力科技股份有限公司 Direct-current power collection system of wave energy power generation device, and control method and system therefor
CN115037120A (en) * 2022-06-09 2022-09-09 合肥工业大学 Two-stage energy router system and method based on modular multi-port converter
CN115037120B (en) * 2022-06-09 2024-04-30 合肥工业大学 Two-stage energy router system and method based on modularized multiport converter

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