CN117955427A - Low-voltage output direct-current electric energy router and photovoltaic access power supply system - Google Patents
Low-voltage output direct-current electric energy router and photovoltaic access power supply system Download PDFInfo
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- CN117955427A CN117955427A CN202410137919.9A CN202410137919A CN117955427A CN 117955427 A CN117955427 A CN 117955427A CN 202410137919 A CN202410137919 A CN 202410137919A CN 117955427 A CN117955427 A CN 117955427A
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- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The invention discloses a low-voltage output direct-current electric energy router and a photovoltaic access power supply system, which comprise at least one power conversion module connected between an electric energy input side and a load side; each power conversion module comprises a high-voltage power module and a low-voltage power module; the input end of the high-voltage power module is respectively connected with the anode and the cathode of the electric energy input side and is used for receiving high-voltage direct current generated by the electric energy input side; the output end of the low-voltage power module is respectively connected with the anode and the cathode of the load side and is used for outputting rated high-voltage direct current; the photovoltaic access power supply system comprises a photovoltaic confluence assembly, a secondary confluence device, a direct current electric energy router and a load side protection device, wherein the output end of the load side protection device is connected with a direct current load; the high-voltage power module is responsible for being connected with 1500V photovoltaic input, the low-voltage power module can realize rated voltage output smaller than 700V, and a diode with small switching loss and low price is used as an output switch component, so that the manufacturing cost is reduced.
Description
Technical Field
The invention relates to the technical field of electric energy conversion, in particular to a low-voltage output direct-current electric energy router and a photovoltaic access power supply system.
Background
Most of the existing new energy power supply sides utilize photovoltaic power generation for energy supply, and for loads with lower rated voltage, the energy supply modes of the photovoltaic power generation are specifically divided into the following two modes:
① DC/AC, AC/DC AC conversion mode: the high voltage (such as 1500V) generated by photovoltaic power generation is changed into 220V alternating current through a grid-structured inversion device and connected to an alternating current power grid, the alternating current power grid is converted into direct current voltage through an alternating current-direct current converter, and the direct current power is supplied to a direct current load after being rectified through a step-down rectifying device.
② High voltage dc conversion scheme: after energy is collected by adopting a 1500V voltage level, a general direct current conversion device with a two-level topological structure is used for direct current conversion, and a load system is connected after the direct current power is reduced in voltage, and as the input voltage before the direct current power is reduced and converted is higher, a power electronic switch with high voltage level is needed to be used as a switching device of the conversion device, and the power electronic switch has low speed, high switching loss and high price.
Disclosure of Invention
The invention aims to provide a low-voltage output direct-current electric energy router and a photovoltaic access power supply system, which are used for solving the technical problems of high cost and loss caused by a plurality of alternating-current and direct-current conversion operations and the requirement of using a power electronic switch with high voltage level as a switching device of a conversion device for direct-current voltage reduction in the prior art.
In order to solve the technical problems, the invention specifically provides the following technical scheme: a low voltage output direct current power router comprising:
At least one power conversion module connected between the power input side and the load side;
Each power conversion module comprises a high-voltage power module and a low-voltage power module;
the input end of the high-voltage power module is respectively connected with the anode and the cathode of the electric energy input side and is used for receiving high-voltage direct current generated by the electric energy input side;
and the output end of the low-voltage power module is respectively connected with the anode and the cathode of the load side and is used for outputting rated high-voltage direct current.
As a preferable mode of the present invention, the high-voltage power module is a stacked multi-level power unit connected to the electric energy input side, the stacked multi-level power unit is formed with an anode input port and a cathode input port, and the stacked multi-level power unit is used for receiving the high-voltage direct current generated by the electric energy input side;
the low-voltage power module is a two-level H-bridge unit connected with the load side, the two-level H-bridge unit is provided with an anode output port and a cathode output port, and the two-level H-bridge unit is used for generating low-voltage direct current;
The stacked multi-level power unit is connected with the two-level H-bridge unit through an isolation transformer.
As a preferable scheme of the invention, a resonant capacitor group is arranged on a connecting line of the isolation transformer and the two-level H-bridge unit.
As a preferable scheme of the invention, the positive output ports of the stacked multi-level power units of each power conversion module are connected with a chopper reactor, and the positive output ports connected with the chopper reactors are connected in parallel and then connected with the positive electrode of the electric energy input side.
As a preferred scheme of the invention, when the number of the power conversion modules exceeds one, the input ends of all the power conversion modules are connected in parallel, and the positive input port and the negative input port formed by connecting all the stacked multi-level power units in parallel are connected with the positive electrode and the negative electrode of the electric energy input side in a matching way;
And the output ends of all the power conversion modules are connected in parallel, and the positive output port and the negative output port formed by connecting the two-level H bridge units in parallel are connected with the positive electrode and the negative electrode of the load side in a matching way.
As a preferable scheme of the invention, a filter capacitor is arranged between an anode input port and a cathode input port which are formed by connecting input ends of all power conversion modules in parallel.
In order to solve the technical problem, the invention also provides a photovoltaic access power supply system of the low-voltage output direct-current electric energy router, which comprises:
the photovoltaic confluence assembly is used for connecting the output ends of the photovoltaic power generation strings in parallel;
The secondary confluence device is used for connecting the output ends of the photovoltaic confluence assemblies in parallel;
The direct-current electric energy router is connected with the output end of the secondary confluence device;
A load side protection device connected with the output end of the direct current power router;
the output end of the load side protection device is connected with a direct current load.
As a preferable scheme of the invention, the photovoltaic confluence assembly comprises a plurality of photovoltaic confluence boxes formed by series-parallel connection of photovoltaic power generation groups, and the photovoltaic confluence boxes are connected in parallel through secondary confluence to form a secondary confluence device, and the output end of the secondary confluence device forms a photovoltaic positive electrode line and a photovoltaic negative electrode line;
And the photovoltaic positive electrode circuit and the photovoltaic negative electrode circuit are respectively connected with a positive electrode input port and a negative electrode output port formed by the direct current electric energy router in a matching way.
As a preferred embodiment of the present invention, the load-side protection device includes an output filter, an output fuse protector, an output reverse protector, and an output isolation switch connected in series.
Compared with the prior art, the invention has the following beneficial effects:
The high-voltage power module is responsible for being connected with 1500V photovoltaic input, adopts a parallel stacked level structure, can realize 1100V-1600V voltage output, has higher overall switching frequency and lower device switching frequency, and the output end of the low-voltage power module is connected in a parallel mode, so that rated voltage output smaller than 700V can be realized, direct current step-down treatment can be directly realized, and the manufacturing cost and loss are reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It will be apparent to those of ordinary skill in the art that the drawings in the following description are exemplary only and that other implementations can be obtained from the extensions of the drawings provided without inventive effort.
Fig. 1 is a schematic structural diagram of a single power conversion module in a dc power router according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a whole dc power router according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a photovoltaic access dc load power supply system according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a low-voltage output direct-current electric energy router, which comprises at least one power conversion module connected between an electric energy input side and a load side, wherein the structure of each power conversion module is shown in fig. 1, and the structure of the low-voltage output direct-current electric energy router formed by a plurality of power conversion modules is shown in fig. 2.
Each power conversion module comprises a high-voltage power module and a low-voltage power module, wherein the input end of the high-voltage power module is connected with the positive electrode and the negative electrode of the electric energy input side respectively and used for receiving high-voltage direct current generated by the electric energy input side, and the output end of the low-voltage power module is connected with the positive electrode and the negative electrode of the load side respectively and used for outputting rated high-voltage direct current.
Further, the high voltage power module is specifically a stacked multi-level power unit connected to the electric energy input side, the stacked multi-level power unit is formed with an anode input port and a cathode input port, the stacked multi-level power unit is used for receiving the high voltage direct current generated by the electric energy input side, and the structural composition and the connection relationship of the stacked multi-level power unit are shown in fig. 1.
The low-voltage power module is specifically a two-level H-bridge unit connected with a load side, the two-level H-bridge unit is formed with an anode output port and a cathode output port and is used for generating low-voltage direct current, wherein the two-level H-bridge unit is connected by using two groups of diode assemblies connected in parallel, and the specific structural composition and connection relation are shown in figure 1.
The stacked multi-level power unit is connected with the two-level H bridge units through an isolation transformer, and a resonant capacitor group is arranged on a connecting line of the isolation transformer and the two-level H bridge units.
In this embodiment, the electric energy input side is specifically a photovoltaic string, specifically generates 1500V photovoltaic direct current, the stacked multi-level power unit is responsible for being connected with 1500V photovoltaic input, and the stacked multi-level power unit adopts a stacked level structure, so that 1100V-1600V voltage output can be achieved, and the stacked multi-level power unit has a higher overall switching frequency and a lower device switching frequency.
The high-voltage power module is responsible for being connected with 1500V photovoltaic input, adopts a parallel stacked level structure, can realize 1100V-1600V voltage output, and has higher overall switching frequency and lower device switching frequency.
The low-voltage power module (i.e. the two-level power unit) adopts a parallel connection mode and a load side, so that rated voltage output smaller than 700V can be realized, and a diode with low price, high switching frequency and small switching loss can be used as a switching device, thereby reducing cost and loss.
Preferably, when the number of the power conversion modules exceeds one, the input ends of all the power conversion modules are connected in parallel, the positive input port and the negative input port formed by connecting all the stacked multi-level power units in parallel are connected with the positive electrode and the negative electrode of the electric energy input side in a matching way, and a filter capacitor is arranged between the positive input port and the negative input port formed by connecting the input ends of all the power conversion modules in parallel.
The filter capacitor has two functions:
1. Providing a path for high frequency current so that the high frequency current does not flow through the photovoltaic panel;
2. The stability of tracking control of the maximum power point of the photovoltaic is improved, and control instability caused by too high voltage change speed is avoided when the voltage of the photovoltaic side is regulated.
The output ends of all the power conversion modules are connected in parallel, and the positive output port and the negative output port formed by connecting the two-level H bridge units in parallel are connected with the positive electrode and the negative electrode of the load side in a matching way.
The positive output ports of the stacked multi-level power units of all the power conversion modules are connected with chopper reactors, and the positive output ports connected with the chopper reactors are connected in parallel and then connected with the positive electrode of the energy input side.
The whole low-voltage output direct-current electric energy router adopts a mode of connecting a plurality of groups of power conversion modules in parallel, so that the standard modules are convenient to build the whole machine with different powers, and spare parts are convenient to store and maintain the system.
In addition, the power conversion modules are in a staggered parallel connection mode at the input side, namely carrier phases are staggered, harmonic waves of carrier frequencies are eliminated, the electric energy quality of the photovoltaic side is improved, and adverse effects of the harmonic waves on the photovoltaic panel are reduced.
In addition, this embodiment also provides a photovoltaic access dc load power supply system of the low-voltage output dc power router, as shown in fig. 3, which specifically includes:
the photovoltaic confluence assembly is used for connecting the output ends of the photovoltaic power generation strings in parallel;
The secondary confluence device is used for connecting the output ends of the photovoltaic confluence assemblies in parallel;
The direct-current electric energy router is connected with the output end of the secondary converging device;
A load side protection device connected with the output end of the DC power router;
The output end of the load side protection device is connected with the direct current load, and the load side protection device comprises an output filter, an output fuse protector, an output backstop protector and an output isolating switch which are connected in series.
The photovoltaic confluence assembly comprises a photovoltaic confluence box connected with a plurality of photovoltaic power generation groups in series, the photovoltaic confluence boxes are connected in parallel through secondary confluence to form a secondary confluence device, and the output end of the secondary confluence device forms a photovoltaic positive electrode line and a photovoltaic negative electrode line;
the photovoltaic positive electrode circuit and the photovoltaic negative electrode circuit are respectively connected with a positive electrode input port and a negative electrode output port formed by the direct current energy router in a matching way.
It is to supplement that be equipped with in the photovoltaic conflux case and establish the fuse protector, prevent against current protector and the group string current detection subassembly of being connected with every photovoltaic power generation group cluster, the photovoltaic conflux case is established by a plurality of photovoltaic power generation group cluster and is once converged the connection and constitute, and the output of every photovoltaic conflux case is equipped with lightning protection device and output circuit breaker.
The secondary convergence has the advantages of reducing the number and the cost of the photovoltaic string cables, and the cost of the large-section cables with smaller number is obviously lower than that of the small-section cables with larger number under the same current capacity from the economical aspect.
As a typical example, 360 photovoltaic strings are first converged by 15 24-way convergence boxes, and then transmitted through cables, and then secondarily converged.
If only one confluence is used, 360 anodes and cathodes are needed, and 720 photovoltaic cables with the total length of 6mm and the total length of 1500V are 720, and for the photovoltaic cable with the total length of 6mm and the total length of 1500V, the insulation and mechanical protection materials occupy larger cost.
If a secondary confluence mode is used, each photovoltaic group string uses 1 positive electrode and negative electrode, 720 photovoltaic cables with the length of 6mm and 1500V and shorter are used in total, 15 photovoltaic aluminum cables with the length of 185mm and longer are used for outputting after primary confluence, and then secondary confluence is performed. In this embodiment, the larger length of cable is a smaller number of aluminum cables and is less expensive to manufacture.
The system has complete protection capability, can better realize the control and protection of the photovoltaic direct current access load, and is convenient for directly realizing direct current voltage reduction treatment, thereby reducing the loss of the whole power supply system.
The photovoltaic access direct current load power supply system can be directly applied to rated voltage which is smaller than 700V and is output by the low-voltage output direct current power router, and repeated voltage reduction processing is not needed, so that loss is reduced.
The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application, the scope of which is defined by the claims. Various modifications and equivalent arrangements of this application will occur to those skilled in the art, and are intended to be within the spirit and scope of the application.
Claims (9)
1. A low-voltage output direct current power router is characterized by comprising,
At least one power conversion module connected between the power input side and the load side;
Each power conversion module comprises a high-voltage power module and a low-voltage power module;
the input end of the high-voltage power module is respectively connected with the anode and the cathode of the electric energy input side and is used for receiving high-voltage direct current generated by the electric energy input side;
and the output end of the low-voltage power module is respectively connected with the anode and the cathode of the load side and is used for outputting rated high-voltage direct current.
2. A low voltage output DC power router as claimed in claim 1, wherein,
The high-voltage power module is a stacked multi-level power unit connected with the electric energy input side, the stacked multi-level power unit is provided with an anode input port and a cathode input port, and the stacked multi-level power unit is used for receiving high-voltage direct current generated by the electric energy input side;
the low-voltage power module is a two-level H-bridge unit connected with the load side, the two-level H-bridge unit is provided with an anode output port and a cathode output port, and the two-level H-bridge unit is used for generating low-voltage direct current;
The stacked multi-level power unit is connected with the two-level H-bridge unit through an isolation transformer.
3. A low voltage output DC power router as claimed in claim 2, wherein,
And a resonant capacitor group is arranged on a connecting line of the isolation transformer and the two-level H bridge unit.
4. A low voltage output DC power router as claimed in claim 2, wherein,
The positive output ports of the stacked multi-level power units of each power conversion module are connected with chopping reactance, and the positive output ports connected with the chopping reactance are connected in parallel and then connected with the positive electrode of the electric energy input side.
5. A low voltage output DC power router as claimed in claim 2, wherein,
When the number of the power conversion modules exceeds one, the input ends of all the power conversion modules are connected in parallel, and the positive input port and the negative input port formed by connecting all the stacked multi-level power units in parallel are connected with the positive electrode and the negative electrode of the electric energy input side in a matching way;
And the output ends of all the power conversion modules are connected in parallel, and the positive output port and the negative output port formed by connecting the two-level H bridge units in parallel are connected with the positive electrode and the negative electrode of the load side in a matching way.
6. A direct current power router according to claim 1 or 4, wherein,
And filter capacitors are arranged between the positive input ports and the negative input ports, which are formed by connecting the input ends of all the power conversion modules in parallel.
7. A photovoltaic access power supply system employing the dc power router of any one of claims 1-6, comprising:
the photovoltaic confluence assembly is used for connecting the output ends of the photovoltaic power generation strings in parallel;
The secondary confluence device is used for connecting the output ends of the photovoltaic confluence assemblies in parallel;
The direct-current electric energy router is connected with the output end of the secondary confluence device;
A load side protection device connected with the output end of the direct current power router;
the output end of the load side protection device is connected with a direct current load.
8. The photovoltaic-access power supply system of claim 7, wherein,
The photovoltaic confluence assembly comprises a photovoltaic confluence box connected with a plurality of photovoltaic power generation groups in series, the photovoltaic confluence boxes are connected in parallel through secondary confluence to form a secondary confluence device, and the output end of the secondary confluence device forms a photovoltaic positive electrode line and a photovoltaic negative electrode line;
And the photovoltaic positive electrode circuit and the photovoltaic negative electrode circuit are respectively connected with a positive electrode input port and a negative electrode output port formed by the direct current electric energy router in a matching way.
9. The photovoltaic-access power supply system of claim 7, wherein,
The load side protection device comprises an output filter, an output fuse protector, an output backstop protector and an output isolating switch which are connected in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410137919.9A CN117955427A (en) | 2024-02-01 | 2024-02-01 | Low-voltage output direct-current electric energy router and photovoltaic access power supply system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410137919.9A CN117955427A (en) | 2024-02-01 | 2024-02-01 | Low-voltage output direct-current electric energy router and photovoltaic access power supply system |
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| CN117955427A true CN117955427A (en) | 2024-04-30 |
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| CN202410137919.9A Pending CN117955427A (en) | 2024-02-01 | 2024-02-01 | Low-voltage output direct-current electric energy router and photovoltaic access power supply system |
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