CN113890122A - Alternating current-direct current multiport power distribution system for office residential area - Google Patents
Alternating current-direct current multiport power distribution system for office residential area Download PDFInfo
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- CN113890122A CN113890122A CN202111197059.0A CN202111197059A CN113890122A CN 113890122 A CN113890122 A CN 113890122A CN 202111197059 A CN202111197059 A CN 202111197059A CN 113890122 A CN113890122 A CN 113890122A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J5/00—Circuit arrangements for transfer of electric power between ac networks and dc networks
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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
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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
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
- H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
- H02M5/10—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers
- H02M5/12—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers for conversion of voltage or current amplitude only
Abstract
The invention belongs to the technical field of power distribution networks, and particularly relates to an alternating current-direct current multiport power distribution system for office residential parks. According to the alternating current-direct current multi-port power distribution system for the office residential park, an alternating current power supply, a power frequency transformer, at least one group of alternating current-direct current conversion circuit, a plurality of first direct current buses, two second direct current buses, a converter module, a direct current load module and an alternating current load module form a multi-voltage-level output alternating current-direct current hybrid power distribution network system, and the alternating current-direct current hybrid power distribution network system overcomes the technical problems of high energy conversion loss, high system cost, low reliability, low energy consumption rate in place and poor power consumption flexibility in the prior art.
Description
Technical Field
The invention belongs to the technical field of power distribution networks, and particularly relates to an alternating current-direct current multiport power distribution system for office residential parks.
Background
In recent years, with the rapid development of social economy and the rapid construction of modern cities, the size and the types of loads in urban power distribution networks are increasing, and the traditional alternating current power distribution networks face a plurality of new problems. The traditional alternating-current distribution inlet wire power supply is a 10kV power supply, three-phase four-wire 380V low-voltage alternating current is obtained through a distribution transformer, and then an electric load is supplied through an alternating-current 220V distribution network. On one hand, the rapid increase of the urban scale leads to the continuous expansion of the power supply range of the urban power distribution network, so that the traditional power distribution network faces the problems of increased line loss and increased voltage fluctuation. Meanwhile, the increasing tension of the power supply line also puts higher requirements on the transmission capacity of the line. On the other hand, with the rapid development of power electronic technology, the efficiency is improved, and the direct current load flexible to control is continuously increased, such as a computer, an LED lighting device, an electric vehicle, and the like. In practical situations, these loads all require a multi-stage converter to be connected to the ac grid; in addition, in the distributed power generation system, the output of the photovoltaic cell panel is direct current, and the direct current can be incorporated into an alternating current distribution network through a multi-stage converter. Therefore, a large number of current conversion processes exist in the conventional alternating current power distribution network, and the use of the current converters in a large number can reduce the power utilization efficiency, increase the equipment investment, and simultaneously generate a large number of harmonic pollution to influence the power quality of the power distribution network. Finally, the risk of personal electric shock exists in alternating current 220V power distribution, and especially, the safety of power utilization is difficult to guarantee under extreme conditions.
Therefore, the multi-stage electric energy conversion loss is high, the power distribution flexibility is poor, and the electric energy quality is difficult to guarantee in the existing alternating current distribution network. The adoption of the AC-DC hybrid power distribution and utilization technology can effectively reduce the intermediate link of AC-DC conversion in the power distribution and utilization process, improve the efficiency, reliability and flexibility of power distribution and utilization, and properly solve the problem of system stability after the distributed new energy and energy storage system is accessed.
Compared with an alternating-current distribution network, the direct-current distribution network has the advantages of large power supply capacity, small line loss, high electric energy quality, convenience for access of various power supplies and loads and the like, and has wide application prospect. However, in the current development situation of the power distribution network in China, the direct-current power distribution network cannot completely replace the alternating-current power distribution network in a short time, so that the construction of the alternating-current and direct-current hybrid power distribution network on the basis of the alternating-current power distribution network is more practical.
Aiming at the phenomena of the emergence of a distributed power supply, the direct current of electric equipment, the mass use of electric automobiles and the like, the power distribution network is effectively researched by various large enterprises and colleges in China: further exploration on an AC/DC distribution network is conducted by patents of Dongguan power supply office of Guangdong power grid and Guangdong power grid, Inc. (application number: 202011008078.X) of the Guangdong power grid, Inc., and a self-organizing electric energy router (application number: 201710414906.1) of Zhejiang university, wherein the AC/DC distribution network is applied to an office living park.
The structure of a distribution network in the patent, namely an alternating current-direct current hybrid distribution network system applied to an office living park, comprises a power electronic transformer, a load side and a comprehensive energy source side. The power electronic transformer is provided with a plurality of ports, a power supply side is connected with the power electronic transformer through a 10kV alternating current power supply, a load side is connected with the power electronic transformer through a 380V alternating current bus and a +/-375V direct current bus, and the power electronic transformer regulates and controls the comprehensive energy source side by judging the tide direction. Although the power electronic transformer can compensate the power requirement of a power system in fault, the power electronic transformer is limited by insufficient voltage resistance and current resistance of the existing power electronic devices, and a plurality of power electronic modules are required to be cascaded, connected in parallel and subjected to multiple times of electric energy conversion between alternating current and direct current to obtain the required voltage, so that a large number of power electronic devices are required in the scheme, the price of the power electronic transformer is more expensive than that of a conventional isolation transformer, meanwhile, the reliability of the power electronic transformer is reduced due to the excessive number of the devices, and finally, the loss and the efficiency of the power electronic transformer are high due to the multi-stage electric energy conversion. The above cost, reliability and efficiency deficiencies will directly affect the popularization of the method to practical application.
In the patent self-organizing electric energy router applied to a low-voltage distribution terminal, an electric energy router which is composed of a converter group consisting of a plurality of H-bridge converters, an internal power bus, an equipment interface, a power switch array and a control unit is provided. The device interface is respectively connected with the power bus and the converter by controlling the power switch, the other side port of the converter is connected with other devices by the power bus to realize line reconstruction, and the control unit determines the power supply and the power receiving of the external device by controlling the converter. The invention has reusable power circuit, good stability and fault tolerance, and the device interface can be used in plug and play mode. However, in this scheme, a power switch array is required to perform function reconstruction on the H-bridge converter to realize DC-DC, DC-AC, and AC-DC conversion, and a large number of power switches used to improve flexibility lead to increased system complexity, excessive cost, and reduced reliability, which is difficult to meet practical application requirements.
Disclosure of Invention
In order to solve the problems, the invention provides an AC/DC multiport power distribution system for office residential parks, which adopts the following technical scheme:
the invention provides an alternating current-direct current multiport power distribution system for office residential parks, which is characterized by comprising the following components in parts by weight: the AC power supply, the industrial frequency transformer, at least one group of AC/DC conversion circuit, a plurality of first DC buses, two second DC buses, a converter module, a DC load module and an AC load module, wherein the industrial frequency transformer and the AC power supply are arranged in a one-to-one correspondence manner, the high-voltage side of the industrial frequency transformer is connected with the AC power supply by adopting a delta connection method, the low-voltage side adopts three single-phase independent windings, the low-voltage side is respectively connected with the AC/DC conversion circuit and the AC load module, the DC load module is provided with a high-voltage load unit and a low-voltage load unit, the AC side of the AC/DC conversion circuit is connected with the low-voltage side of the industrial frequency transformer, the DC side is connected with the high-voltage load unit through the first DC buses and the converter module, the converter module is at least provided with a bus converter and a charging converter, the input side of the bus converter is connected with the first DC buses, the output side is connected with the low-voltage load unit through a second direct-current bus, the input side of the charging converter is connected with the first direct-current bus, and the output side of the charging converter is connected with the high-voltage load unit.
The invention provides an alternating current-direct current multiport power distribution system for office residential parks, which is characterized by further comprising: the energy module is provided with a distributed energy unit and an energy storage unit, wherein the converter module is further provided with a photovoltaic converter and an energy storage converter, the distributed energy unit is connected with the output side of the photovoltaic converter, and the energy storage unit is connected with the output side of the energy storage converter.
The alternating current-direct current multi-port power distribution system for the office residential park, provided by the invention, can also have the characteristics that the distributed energy source unit is distributed photovoltaic or distributed wind power, and the energy storage unit is a lithium battery, a super capacitor or a hydrogen fuel battery.
The alternating current-direct current multiport power distribution system for the office residential park, provided by the invention, can also have the characteristics that the photovoltaic converter, the energy storage converter and the bus converter are all DC/DC converters, the photovoltaic converter is a unidirectional DC/DC converter, and the energy storage converter and the bus converter are all isolated bidirectional DC/DC converters.
The alternating current-direct current multiport power distribution system for the office residential park, provided by the invention, can also have the characteristic that the charging converter is an isolated bidirectional DC/DC converter or a DC/AC converter.
The alternating current-direct current multi-port power distribution system for the office residential park can also have the characteristic that a circuit of the isolated bidirectional DC/DC converter is in a double-active bridge (DAB) topological structure.
The alternating current-direct current multi-port power distribution system for the office residential park, provided by the invention, can also be characterized in that the line voltage of an alternating current power supply is 10KV, the voltage of three single-phase windings on the low-voltage side of a power frequency transformer is 220V alternating current, the voltage between two adjacent first direct current buses is 375V, and the voltage between two second direct current buses is 48V.
The alternating current-direct current multiport power distribution system for the office residential park can also have the characteristic that the alternating current-direct current conversion circuit is a three-phase H-bridge converter circuit.
The alternating current-direct current multiport power distribution system for the office residential park, provided by the invention, can also be characterized in that the low-voltage load unit is provided with a plurality of IT load interfaces for supplying power to IT loads with the direct current voltage of 48V, and the alternating current load module is provided with at least one alternating current load interface for supplying power to loads with the alternating current voltage of 220V.
The alternating current-direct current multi-port power distribution system for the office residential park, provided by the invention, can also have the characteristic that the high-voltage load unit is an electric vehicle charging pile and is used for supplying power to the electric vehicle.
Action and Effect of the invention
According to the alternating current-direct current multi-port power distribution system for the office residential park, an alternating current power supply, a power frequency transformer, at least one group of alternating current-direct current conversion circuits, a plurality of first direct current buses, two second direct current buses, a converter module, a direct current load module and an alternating current load module form a multi-voltage-level output alternating current-direct current hybrid power distribution network system. The alternating current-direct current hybrid power distribution network system solves the technical problems of high energy conversion loss, high system cost, low reliability, low energy consumption rate in place and poor power utilization flexibility in the prior art, and can effectively reduce energy waste and improve power utilization flexibility. The invention realizes the interconnection of an alternating current power supply and a direct current power grid through a power frequency transformer and an alternating current-direct current conversion circuit, the high-voltage side of the power frequency transformer adopts a delta connection method, the low-voltage side adopts three single-phase independent windings, and the three single-phase windings on the low-voltage side are mutually independent and are not connected to provide phase-to-phase isolation for a three-phase H-bridge converter. The transformer can be transformed by adopting a common three-phase three-column Dy11 distribution transformer, and has the functions of voltage coupling and phase-to-phase isolation, so that the cost of the device is reduced.
Drawings
FIG. 1 is an overall block diagram of an AC/DC multiport power distribution system according to a first embodiment of the present invention;
fig. 2 is a structural diagram of an H-bridge converter according to a first embodiment of the present invention;
FIG. 3 is a topology diagram of a DC/DC converter according to a first embodiment of the present invention;
FIG. 4 is an overall block diagram of an AC/DC multiport power distribution system according to a second embodiment of the present invention;
FIG. 5 is an overall block diagram of an AC/DC multiport power distribution system in accordance with a third embodiment of the present invention;
fig. 6 is an overall block diagram of an ac/dc multiport power distribution system according to a fourth embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings.
< example one >
The present embodiment provides a ac/dc multiport power distribution system 100 for supplying power to an office residential park.
Fig. 1 is an overall block diagram of an ac/dc multiport power distribution system according to an embodiment of the present invention.
As shown in fig. 1, the ac/dc multiport power distribution system 100 includes a 10KV ac power source 10, a power frequency transformer 20, a dc load module 30, an energy module 40, a converter module 50, a set of ac/dc conversion circuits 60, an ac load module 70, two first dc buses 80, and two second dc buses 90.
The power frequency transformer 20 is a three-phase three-limb type and is arranged in one-to-one correspondence with the alternating current power supply 10. The high-voltage side of the industrial frequency transformer 20 is connected with the alternating current power supply 10 by adopting a delta connection method, the low-voltage side adopts three single-phase independent windings, and the low-voltage side is respectively connected with the alternating current-direct current conversion circuit 30 and the alternating current load module 80. The voltage grade of the high-voltage side of the power frequency transformer 20 is 10kV, and the voltage of each phase of independent winding of the low-voltage side is 220V of alternating current.
The dc load module 30 has a high-voltage load unit 31 and a low-voltage load unit 32. In this embodiment, the high voltage load unit 31 is an electric vehicle charging pile for supplying power to an electric vehicle, and may also be a high power dc load such as an air conditioner in other embodiments. The low voltage load unit 32 has a plurality of IT load ports for supplying IT loads with a dc voltage of 48V.
The energy module 40 has a distributed energy unit 41 and an energy storage unit 42. In the present embodiment, the distributed energy unit 41 is a distributed photovoltaic. The energy storage unit 42 is a lithium battery.
The converter module 50 has a photovoltaic converter 51, an energy storage converter 52, a bus converter 53 and a charging converter 54. One side of the photovoltaic converter 51 is connected to the first dc bus, and the other side is connected to the distributed energy unit 41 (photovoltaic panel). The photovoltaic converter 51 has a unidirectional energy flow direction, and is used for flowing from the photovoltaic cell to the direct current bus, so that the photovoltaic converter can control the photovoltaic panel to operate at the maximum power tracking point. One side of the energy storage converter 52 is connected to the first dc bus, and the other side is connected to the energy storage unit 42 (lithium battery). The energy flow direction of the energy storage converter 52 is bidirectional, and the energy flow direction may be from the first dc bus to the energy storage unit 42, or from the energy storage unit 42 to the first dc bus. The bus converter 53 has an input side connected to the first dc bus 80 and an output side connected to the low-voltage load unit 32 through the second dc bus 90. The bus bar converter 53 may have a bidirectional energy flow direction, and may flow from the first dc bus bar 80 to the second dc bus bar 90 or from the second dc bus bar 90 to the first dc bus bar 80. The charging converter 54 has an input side connected to the first dc bus 80 and an output side connected to the high-voltage load unit 31. The voltage between the two first dc buses 80 is 375V, and the voltage between the two second dc buses 90 is 48V.
The photovoltaic converter 51, the energy storage converter 52 and the bus converter 53 are all DC/DC converters. The photovoltaic converter 51 is a unidirectional DC/DC converter. The energy storage converter 52 and the bus converter 53 are both isolated bidirectional DC/DC converters. The charging converter 54 is an isolation type bidirectional DC/DC converter or a DC/AC converter. The number of the charging converters 54 in the present embodiment is two, and the charging converters are a DC/DC converter and a DC/AC converter, respectively. The DC/DC charging converter and the DC/AC charging converter can meet different charging requirements of the electric vehicle, when the electric vehicle needs to be rapidly charged, the DC/DC charging converter can be used for carrying out direct current charging, when the rapid charging is not needed, the service life of the vehicle is more considered, and the DC/AC charging converter can be selected for carrying out alternating current charging.
The ac side of the ac-dc conversion circuit 60 is connected to the low-voltage side of the commercial frequency transformer 20, and the dc side is connected to the high-voltage load unit 31 through the first dc bus 80 and the converter module 50 in this order. The ac-dc conversion circuit 60 is a three-phase H-bridge converter circuit having a three-phase H-bridge converter. An inverter circuit of the three-phase H-bridge converter is of a three-phase H-bridge structure.
Fig. 2 is a structural diagram of an H-bridge converter according to a first embodiment of the present invention.
The 10kV alternating current of the alternating current power supply 10 is reduced in voltage by the power frequency transformer 20 and inverted into direct current by the H-bridge converter, a three-phase H-bridge is adopted as an inversion circuit, and a single H-bridge structure is shown in figure 2. L1 is the leakage inductance of the transformer, which is the network side inductance of the inverter LCL filter, L2 is the inverter side filter inductance, C1 is the ac filter capacitance, C2 is the dc filter capacitance, Q1, Q2, Q3, Q4 are all power electronic switching devices, which may be IGBT/diode modules based on silicon material, MOSFETs, or switching devices based on silicon carbide or gallium nitride. D1-D4 are anti-parallel diodes of S1-S4, respectively.
Fig. 3 is a topology diagram of a DC/DC converter in the first embodiment of the present invention.
The DC power inverted by the H-bridge converter is rectified into DC power of a voltage level required by the energy module 40 and the DC load module 30 by the DC/DC converter in the converter module 50. The rectification circuit adopts a DAB topological structure, and the DAB topological structure is shown in figure 3. The circuit topology is composed of a high-frequency transformer T, an inductor Lr, an input capacitor Cin, an output capacitor Cout, a full bridge H1 and a full bridge H2. The transformer transformation ratio is N:1, and the specific value of N can be adjusted according to the load requirement. S1-S8 in the full bridge H1 and the full bridge H2 are all power electronic switching devices, which can be IGBT/diode modules and MOSFETs based on silicon materials, and can also be switching devices based on silicon carbide or gallium nitride; D1-D8 are anti-parallel diodes of S1-S8, respectively.
The ac load module 70 has at least one ac load port connected to the low-voltage side of the industrial frequency transformer 20 for supplying power to a load with an ac voltage of 220V. The number of the ac load ports in this embodiment is 1.
The embodiment of the ac/dc multiport power distribution system 100 is as follows:
the 10kV alternating-current voltage side is a power grid power supply inlet wire and is directly connected to the high-voltage side of the power frequency transformer, the power frequency transformer is a three-phase three-column type, the high-voltage side of the power frequency transformer adopts a delta connection method, and the low-voltage side of the power frequency transformer adopts a three-phase independent winding; the low-voltage side of the transformer can lead out an outlet terminal of 220V AC to be connected with 220V AC load. Meanwhile, each phase input end of the three-phase H-bridge converter is respectively connected with a low-voltage side outlet end of the power frequency transformer, and the direct current sides of the three-phase H-bridge converter are connected together to form a 375V first direct current bus. The 375V first DC bus connects the class 4 DC/DC converters and the 1 DC/AC converter. One type of DC/DC converter is a photovoltaic converter, and electric energy generated by photovoltaic power generation enters a first direct current bus side through the converter to supply power to a load. One type of DC/DC converter is an energy storage bidirectional converter, the input side of the DC/DC converter is connected with a 375V direct current bus, and the output side of the DC/DC converter is used for connecting an energy storage unit. One DC/DC converter is a bus converter, the input side of the bus converter is connected with a 375V first direct current bus, and the output side of the bus converter is connected with a 48V second direct current bus formed by conversion of the bus converter; and the output side of the other DC/DC converter is connected with the electric vehicle and is used as a direct current charging pile of the electric vehicle. Energy in the energy storage unit and distributed energy units (photovoltaic) are respectively charged to electric vehicles with different voltage requirements through a photovoltaic converter and an energy storage converter through a first direct current bus and a charging converter. Similarly, the input side of the DC/AC converter is connected to the 375V first DC bus, and the output side is connected to the electric vehicle as an AC charging post of the electric vehicle. The formed 48V second direct current bus can simultaneously supply power for a plurality of IT loads necessary for office life, and the 'plug and play' of the IT loads is realized.
The alternating current and direct current hybrid power distribution network system is divided into 4 voltage levels, wherein 10kV alternating current voltage is input into the whole alternating current and direct current power distribution system and is directly connected to the high-voltage side of a power frequency transformer. The output has 375V DC voltage, 48V DC voltage and 220V AC voltage. The 375V first direct-current voltage bus is connected to the electric energy of photovoltaic power generation, the electric vehicle and the energy storage unit through the converter module. The 48V second direct-current voltage bus can be connected into a plurality of IT loads at the same time. The 220V alternating voltage bus is connected to an alternating load. According to the demands of different loads and power supplies, electric energy can flow into different buses, and the accessed energy module and the direct-current load module can flow power at a low-voltage power distribution end, so that the local consumption of energy is realized.
< example two >
The present embodiment provides a ac/dc multiport power distribution system 200.
Fig. 4 is an overall block diagram of an ac/dc multiport power distribution system according to a second embodiment of the present invention.
As shown in fig. 4, the system of this embodiment has substantially the same structure as the system of the first embodiment, except that the dc sides of the three-phase H-bridge converters of this embodiment are cascaded together to form 4 first dc buses. The voltage between two adjacent first bus bars is 375V.
The embodiment of the ac/dc multiport power distribution system 200 is as follows:
the 10kV alternating-current voltage side is a power grid power supply inlet wire and is directly connected to the high-voltage side of the power frequency transformer, the power frequency transformer is a three-phase three-column type, the high-voltage side of the power frequency transformer adopts a delta connection method, and the low-voltage side of the power frequency transformer adopts a three-phase independent winding; the low-voltage side of the industrial frequency transformer can lead out an outlet terminal of alternating current 220V to access a load of alternating current 220V. Meanwhile, each phase input end of the three-phase H-bridge converter is respectively connected with a low-voltage side outlet end of the transformer, the direct current sides of the three-phase H-bridge converter are cascaded together to form 4 first direct current buses, and the voltage between the adjacent buses is 375V. Leading out an outlet wire on the first direct current bus, and respectively connecting the outlet wire into the energy storage unit, the distributed energy unit and loads with different voltage requirements through different converters: the energy storage unit is connected into the distribution network system through the energy storage converter; the distributed energy (photovoltaic) is connected into the power distribution network system through a photovoltaic converter; the direct-current voltage obtained by the H-bridge converter is converted into 48V direct-current voltage by the bus converter, and further, a plurality of IT loads are simultaneously connected to a 48V second direct-current voltage bus, so that 'plug and play' of the IT loads is realized; the electric vehicle can be charged by direct current and alternating current through the DC/DC converter and the DC/AC converter. In addition, the energy generated by photovoltaic power generation and the energy in the energy storage unit supply power for the electric vehicle and other loads through the photovoltaic converter, the energy storage converter, the direct-current voltage bus and other converters, so that the local consumption of the energy is realized.
< example three >
The present embodiment provides a ac/dc multiport power distribution system 300.
Fig. 5 is an overall block diagram of an ac/dc multiport power distribution system according to a third embodiment of the present invention.
As shown in fig. 5, the system of the present embodiment has substantially the same structure as the system of the first embodiment, except that: the DC sides of the three-phase H-bridge inverters of this embodiment are cascaded together to form three first DC buses 80 of DC + \ DC0\ DC-of 375V. The number of the ac/dc conversion circuits 60 is two. The ac load module 70 has two ac load ports. The two charging converters are both DC/DC converters.
The embodiment of the ac/dc multiport power distribution system 300 is as follows:
the 10kV alternating-current voltage side is a power grid power supply inlet wire and is directly connected to the high-voltage side of the power frequency transformer, the transformer is a three-phase three-column type, the high-voltage side of the transformer adopts a triangular connection method, the low-voltage side of the transformer is provided with two groups of three-phase low-voltage windings, and each three-phase winding adopts a three-phase winding to be independent; each three-phase low-voltage winding can be led out of an outlet terminal of alternating current 220V to be connected with a load of alternating current 220V. Meanwhile, each phase input end of the 2 three-phase H-bridge converters is respectively connected with the low-voltage side outlet ends of the two groups of transformers, and the direct current sides of the 2 three-phase H-bridge converters are cascaded together to form three first direct current buses of +/-375V DC + \ DC0\ DC-. The DC/DC converter can be connected with the DC + and the DC-first direct current bus at the input side and the electric vehicle at the output side, so that the electric vehicle is charged with direct current. The DC/DC converter is also connected to the DC0 and the DC + (or DC-) DC bus on the input side and the electric vehicle on the output side, thereby charging the electric vehicle with DC power. Therefore, different requirements of electric vehicle charging can be met. In addition, the photovoltaic power generation system is provided with two groups in the embodiment, namely, the DC/DC photovoltaic converter is connected with the DC0 and the DC + (or DC-) first direct current bus on the input side and is connected with the distributed energy source (photovoltaic) on the output side for photovoltaic power generation. In addition, the input side of the DC/DC energy storage converter is connected with the DC0 and the DC + (or DC-) first direct current bus, and the output side of the DC/DC energy storage converter is connected with the distributed energy storage for storing the electric energy. Furthermore, the input side of the DC/DC bus converter is connected with the DC + and the DC-first direct current bus, the output side of the DC/DC bus converter forms a second direct current bus with the voltage of 48V, the outgoing line of the second direct current bus is connected into the IT load necessary for office, and meanwhile, the IT load is supplied with power for a plurality of IT loads necessary for office, so that the 'plug and play' of the IT load is realized.
< example four >
The present embodiment provides a ac/dc multiport power distribution system 400.
Fig. 6 is an overall block diagram of an ac/dc multiport power distribution system according to a fourth embodiment of the present invention.
As shown in fig. 6, the system of the present embodiment has substantially the same structure as the system of the first embodiment, except that: in this embodiment, the number of the 10KV ac power supply 10, the line frequency transformer 20, the ac-dc conversion circuit 60, and the ac load module 70 is two. And the dc sides of the three-phase H-bridge inverters are connected together to form three first dc busses 80 of ± 375V and 0V.
The embodiment of the ac/dc multiport power distribution system 400 is as follows:
the 10kV alternating-current voltage side is a power grid power supply inlet wire and is directly connected to the high-voltage side of the power frequency transformer, the transformer is a three-phase three-column type, the high-voltage side adopts a delta connection method, and the low-voltage side adopts a three-phase independent winding; the low-voltage side of the transformer can lead out an outlet line of alternating current 220V to be connected with a load of alternating current 220V. Meanwhile, the input ends of all phases of the 2 groups of three-phase H-bridge converters are respectively connected with the outlet end of the low-voltage side of the transformer, and the direct current sides of the three-phase H-bridge converters are connected together to form first direct current buses of +/-375V and 0V. The input side of the DC/DC converter is connected with +375V and 0V first direct current buses, and the output side of the DC/DC converter is connected with distributed energy (photovoltaic) for photovoltaic power generation. In addition, the DC/DC converter is connected with the first direct current bus of +375V and 0V at the input side and the electric vehicle at the output side, so that the electric vehicle is charged with direct current.
Effects and effects of the first to fourth embodiments
According to the alternating current-direct current multiport power distribution system for the office residential park, which is disclosed by the first embodiment to the fourth embodiment, the alternating current-direct current hybrid power distribution network system with multi-voltage-level output is formed by the alternating current power supply, the power frequency transformer, at least one group of alternating current-direct current conversion circuits, the plurality of first direct current buses, the two second direct current buses, the converter module, the direct current load module and the alternating current load module. The alternating current-direct current hybrid power distribution network system solves the technical problems of high energy conversion loss, high system cost, low reliability, low energy consumption rate in place and poor power utilization flexibility in the prior art, and can effectively reduce energy waste and improve power utilization flexibility. The invention realizes the interconnection of an alternating current power supply and a direct current power grid through a power frequency transformer and an alternating current-direct current conversion circuit, the high-voltage side of the power frequency transformer adopts a delta connection method, the low-voltage side adopts three single-phase independent windings, and the three single-phase windings on the low-voltage side are mutually independent and are not connected to provide phase-to-phase isolation for a three-phase H-bridge converter. The transformer can be transformed by adopting a common three-phase three-column Dy11 distribution transformer, and has the functions of voltage coupling and phase-to-phase isolation, so that the cost of the device is reduced.
In addition, the alternating current-direct current multiport power distribution system of the embodiment can provide flexible power distribution for loads and distributed power sources. The interface can be directly provided for different alternating current and direct current power supplies and alternating current and direct current loads at the same time, wherein alternating current 220V can be output from the low-voltage side of the transformer, a direct current 375V interface is obtained at the direct current side of the converter by three-phase alternating current input through the 3-phase H-bridge converter, and a direct current 48V voltage interface is obtained after the direct current 375V passes through the DC-DC converter. Traditional alternating current load can insert exchange 220V interface, and distributed photovoltaic power supply, distributed energy storage insert to direct current 375V generating line, and powerful direct current load also inserts direct current 375V generating line like electric motor car, air conditioner, and direct current load such as IT load and illumination inserts direct current 48V and realizes "plug and play", and direct current 48V voltage has essential safety, does not have the personal casualty risk that the electric shock leads to.
In addition, the alternating current-direct current multiport power distribution system of the embodiment is connected into the energy module and the direct current load module in a direct current mode, the energy module and the direct current load module can be connected to the grid for energy exchange through primary energy conversion, local consumption of distributed energy is achieved, the frequency of electric energy conversion is reduced, and the energy utilization efficiency of the system is improved.
In addition, the alternating current-direct current conversion circuit of the alternating current-direct current multiport power distribution system of the embodiment adopts the three-phase H-bridge converter, the H-bridge main circuit is a two-level circuit, each bridge arm only has two power electronic switching devices connected in series, the topological structure is simple, the control is simple and convenient, and the reliability of the converter is high.
In addition, the three-phase H-bridge converter of the ac/dc multiport power distribution system of the above embodiment adopts a unipolar PWM modulation method, and the ac side output equivalent switching frequency is twice the actual switching frequency of the device, and the ac output filter adopts an LCL filter, which can effectively reduce harmonic pollution to the ac power grid.
The above-described embodiments are merely illustrative of specific embodiments of the present invention, and the present invention is not limited to the description of the above-described embodiments.
The energy storage unit in the above embodiment is a lithium battery, the distributed energy unit is a distributed photovoltaic, in other embodiments, the energy storage unit and the distributed energy unit may also be other types of batteries and distributed power supplies, and the types of the energy storage unit and the distributed energy unit are not limited.
Claims (10)
1. An alternating current-direct current multiport power distribution system for office residential parks, comprising:
an AC power supply, a power frequency transformer, at least one group of AC/DC conversion circuits, a plurality of first DC buses, two second DC buses, a converter module, a DC load module and an AC load module,
wherein, the power frequency transformer is arranged corresponding to the AC power supply one by one, the high-voltage side of the power frequency transformer is connected with the AC power supply by adopting a delta connection method, the low-voltage side adopts three single-phase independent windings, and the low-voltage side is respectively connected with the AC-DC conversion circuit and the AC load module,
the DC load module has a high voltage load unit and a low voltage load unit,
the AC side of the AC-DC conversion circuit is connected with the low-voltage side of the industrial frequency transformer, the DC side is connected with the high-voltage load unit through the first DC bus and the converter module in sequence,
the converter module has at least a bus converter and a charging converter,
the input side of the bus converter is connected with the first direct current bus, the output side of the bus converter is connected with the low-voltage load unit through the second direct current bus,
and the input side of the charging converter is connected with the first direct current bus, and the output side of the charging converter is connected with the high-voltage load unit.
2. The office-facing residential park ac/dc multiport power distribution system according to claim 1, further comprising:
an energy module having a distributed energy unit and an energy storage unit,
wherein the converter module also comprises a photovoltaic converter and an energy storage converter,
the distributed energy unit is connected with the output side of the photovoltaic converter,
the energy storage unit is connected with the output side of the energy storage converter.
3. The office-dwelling park-oriented ac/dc multiport power distribution system as recited in claim 2, wherein:
wherein the distributed energy unit is distributed photovoltaic or distributed wind power,
the energy storage unit is a lithium battery, a super capacitor or a hydrogen fuel battery.
4. The office-dwelling park-oriented ac/dc multiport power distribution system as recited in claim 2, wherein:
wherein the photovoltaic converter, the energy storage converter and the bus converter are all DC/DC converters,
the photovoltaic converter is a unidirectional DC/DC converter,
the energy storage converter and the bus converter are both isolated bidirectional DC/DC converters.
5. The office-dwelling park-oriented ac/dc multiport power distribution system as recited in claim 1, wherein:
the charging converter is an isolated bidirectional DC/DC converter or a DC/AC converter.
6. The ac/dc multiport power distribution system for office-facing residential parks according to any of claims 4 and 5, characterized in that:
the circuit of the isolated bidirectional DC/DC converter is a double-active-bridge DAB topological structure.
7. The office-dwelling park-oriented ac/dc multiport power distribution system as recited in claim 1, wherein:
the alternating current-direct current conversion circuit is a three-phase H-bridge converter circuit.
8. The office-dwelling park-oriented ac/dc multiport power distribution system as recited in claim 1, wherein:
wherein the line voltage of the alternating current power supply is 10KV,
the voltage of three single-phase windings on the low-voltage side of the industrial frequency transformer is alternating current 220V,
the voltage between two adjacent first direct current buses is 375V,
the voltage between the two second direct current buses is 48V.
9. The office-dwelling park-oriented ac/dc multiport power distribution system as recited in claim 1, wherein:
wherein the low-voltage load unit has a plurality of IT load ports for supplying an IT load with a DC voltage of 48V,
the alternating current load module is provided with at least one alternating current load port and is used for supplying power to a load with the alternating current voltage of 220V.
10. The office-dwelling park-oriented ac/dc multiport power distribution system as recited in claim 1, wherein:
the high-voltage load unit is an electric vehicle charging pile and is used for supplying power to the electric vehicle.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111197059.0A CN113890122A (en) | 2021-10-14 | 2021-10-14 | Alternating current-direct current multiport power distribution system for office residential area |
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| CN202111197059.0A CN113890122A (en) | 2021-10-14 | 2021-10-14 | Alternating current-direct current multiport power distribution system for office residential area |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116470558A (en) * | 2023-05-18 | 2023-07-21 | 中国华能集团清洁能源技术研究院有限公司 | Energy storage system |
| CN117614047A (en) * | 2024-01-24 | 2024-02-27 | 西安为光能源科技有限公司 | Medium-voltage direct-hanging data center power supply system |
-
2021
- 2021-10-14 CN CN202111197059.0A patent/CN113890122A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116470558A (en) * | 2023-05-18 | 2023-07-21 | 中国华能集团清洁能源技术研究院有限公司 | Energy storage system |
| CN116470558B (en) * | 2023-05-18 | 2024-02-06 | 中国华能集团清洁能源技术研究院有限公司 | Energy storage system |
| CN117614047A (en) * | 2024-01-24 | 2024-02-27 | 西安为光能源科技有限公司 | Medium-voltage direct-hanging data center power supply system |
| CN117614047B (en) * | 2024-01-24 | 2024-03-29 | 西安为光能源科技有限公司 | Medium-voltage direct-hanging data center power supply system |
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