CN105610231A

CN105610231A - Implementation method of direct-current power system

Info

Publication number: CN105610231A
Application number: CN201410629890.2A
Authority: CN
Inventors: 韩玉争; 肖新元; 蓝杨; 张占江; 孙宏宇; 水甲
Original assignee: ZHUHAI SINGYES OPTO-ELECTRICAL TECHNOLOGY Co Ltd; Zhuhai Singyes Renewable Energy Technology Co Ltd; Zhuhai Singyes Green Building Technology Co Ltd
Current assignee: ZHUHAI SINGYES OPTO-ELECTRICAL TECHNOLOGY Co Ltd; Zhuhai Singyes Renewable Energy Technology Co Ltd; Zhuhai Singyes Green Building Technology Co Ltd
Priority date: 2014-11-11
Filing date: 2014-11-11
Publication date: 2016-05-25

Abstract

An implementation method of a direct-current power system is generally applied to a photovoltaic power generation device. The method comprises an inverter and rectifier module, a storage battery charge and discharge module, a direct-current load inverter module, an alternating-current load inverter module, a photovoltaic optimization module and a direct-current bus, wherein the photovoltaic optimization module is used for finding out the maximum power of a photovoltaic panel and transmitting the power to the direct-current bus, the direct-current load control module and the inverter module are used for converting the energy on the direct-current bus into electric energy needed by a load and consuming the electric energy, and the inverter and rectifier module and the storage battery module are used for keeping the bus voltage stable through droop control according to the voltage on the direct-current bus. In the method, there is no need for communication between the modules, and input and output power balance of each module can be achieved by detecting the bus voltage only. The inverter and rectifier module, the optimization module and the storage battery charge and discharge module all can control the running mode thereof by detecting the bus voltage, thus achieving the goal of power matching.

Description

A kind of implementation method of direct current power system

Technical field

The method is generally applied in green energy resource grid-connected system, is particularly applied in photovoltaic energy storage grid-connected system.

Background technology

Photovoltaic electric power grid-connected system is a kind of mode of generally applying, and occupation mode simply adds that government fosters and subsidy economically, has promoted large quantities of project applications; From technical standpoint, this application mode also needs considerable technical measures and means to coordinate concerning electrical network, this is because its generating directly offers electrical network, user's ability electricity consumption after high tension transmission and secondary power transformation, its exchange of electric power and conveying have increased input and the power loss of electric power facility; Neither an efficient way, the just a kind of easy application mode under certain scale from effect.

And the mode that another kind of photovoltaic electric power is generally applied is from net electricity generating and supplying system, generating directly offers load, power supplying efficiency is relatively high, but, unstable and intermittent due to photovoltaic electric power, to requiring the load of stable power-supplying, need by supply load after battery electric power storage, although compared with photovoltaic parallel in system, the consume of electric power transfer has reduced, reduce grid power transmission, the facility of power transformation drops into, but increase the investment of battery and corresponding establishment, and the current battery cost high life is short, electric cost is multiplied, do not possess the photovoltaic electric power marketization in universal significance.

For solving the above-mentioned defect of prior art and application product, make photovoltaic electric power and the electrical network (that is: the electric power of utility grid and micro-electricity) can be rationally and the fusion complementation of science, compared with the application mode of generating electricity by way of merging two or more grid systems with photovoltaic plant (power plant), in the more situation of photovoltaic electric power, being more suitable for generator unit combines with load, send out and use, dissolve nearby, controlled grid-connected; This is also the best applications mode of the generally acknowledged photovoltaic electric power of global industry.

Summary of the invention

The present invention adopts droop control, makes each intermodule can coordinated operation. Each module is adjusted state according to voltage on dc bus, makes within voltage on dc bus maintains a metastable scope, to make input-output power balance. Between each module, there is not direct dependence, as required independent assortment. At areas without electricity, solar energy can be directly changed into the electric energy needing, if necessary, can arbitrarily time, increase battery module, be used for regulated power output, if any electrical network, only need to increase inversion rectification module and just electric energy feedback can be gone to electrical network, or electrical network electric energy is offered to load in the future. This invention has greatly improved the flexibility that photovoltaic system uses, and has solved the defect on prior art and product, has met and has sent out i.e. use, dissolve nearby, and controlled grid-connected optimum mode of operation.

In this invention, each module is determined mode of operation by gathering DC bus-bar voltage, makes within DC bus-bar voltage is operated in stable scope, and each module is determined the switching time of mode of operation by threshold voltage is set. Wherein photovoltaic is optimized module clean energy resource the most, and needing is to use up the electric energy of its generation to greatest extent, and this is also a basic point of departure of this invention.

Brief description of the drawings

Accompanying drawing is a kind of implementation method schematic block diagram of direct current power system;

Fig. 1 is the overall schematic block diagram of direct current power system;

Fig. 2 is inversion rectification module schematic block diagram;

Fig. 3 is accumulator cell charging and discharging schematic block diagram;

Fig. 4 is that photovoltaic is optimized module schematic block diagram;

Fig. 5 is inversion rectification module pattern switching flow figure;

Fig. 6 is that accumulator cell charging and discharging template pattern but changes flow chart;

Fig. 7 is that photovoltaic is optimized template pattern switching flow figure.

Specific embodiments

As embodiment, by reference to the accompanying drawings a kind of direct current power system of the present invention is described, still, technology of the present invention and scheme are not limited to the content that the present embodiment provides.

Accompanying drawing 1 has provided a kind of theory diagram of direct current power system. As shown in the figure, native system comprises: inversion rectification module 100, and accumulator cell charging and discharging pattern 200, DC load control module 300, inversion module 400, dc bus 500 and photovoltaic are optimized module 600. Wherein, the effect of inversion rectification module 100 is in the time that the voltage on dc bus is greater than certain value, and inversion rectification module 100 is operated in inverter mode, the energy on dc bus is sent to commercial electrical network and gets on; In the time that the voltage on dc bus is less than certain value, inversion rectification module is operated in rectification state, and the electric energy in commercialization is sent on dc bus and is used for load. The effect of accumulator cell charging and discharging module 200 is in the time that solar energy electric weight is greater than the electric weight of load consumption, if battery is not full of electric weight, solar energy dump energy charges to battery by accumulator cell charging and discharging module, in the time that battery is full of electric weight, the automatic disconnection of charge-discharge modules 200 is connected with dc bus 100. In the time that solar energy electric weight is less than the electric energy of load consumption, as internal storage battery has electric energy, accumulator cell charging and discharging module is operated in electric discharge filling, and storage battery energy is fed back on dc bus, gives dc bus to support. DC load control module 300 is that the electric energy on dc bus is converted to the electric energy that load needs with the effect of inversion module 400, and provides electric energy support to load. The effect of dc bus 500 is that each module is coupled together, the passage that provides each module electric energy mutually to change. The effect that photovoltaic is optimized module 600 is to make photovoltaic panel be operated in maximum power point, output electric energy to greatest extent, under normal circumstances, photovoltaic is optimized module and is operated in maximum power output pattern, after output voltage is higher than certain value, photovoltaic is optimized module and is thought that its output electric energy is too high, under this state, photovoltaic Optimizing Mode 600 is operated in limit power mode, or constant voltage mode, be that output voltage is constant, output current changes with bearing power; After output current is higher than certain value, photovoltaic is optimized module and is thought that its output current is excessive and in guard mode, and under this state, photovoltaic is optimized module and is operated in constant current mode. So all by detecting the voltage on dc bus, co-ordination makes input-output power coupling to each mould, reaches and utilizes to greatest extent solar energy efficiency, realizes and sends out i.e. use, dissolve nearby, controlled grid-connected object.

Fig. 2 is the logic diagram of inversion rectification module 100. Comprising power control module 101, DC voltage acquisition module 102 and controller 103. In addition, inversion rectification module also should comprise line voltage acquisition module, input and output protection etc. Wherein, the structure of power control mode 101 is according to the difference of power and different. In the time being single-phase grid-connected, generally adopting full-bridge topologies, and with filter circuit and isolating transformer, play the effect of filtering, isolation transformation; Generally adopt the topological structure of three-phase bridge when being three when grid-connected, and with filter circuit and isolating transformer, play the effect of filtering, isolation transformation. The effect of DC voltage acquisition module 102 is the voltage gathering on dc bus, and through proportional amplifier, filtering, the links such as AD conversion are passed to the pattern switch code 104 in controller DC bus-bar voltage information, for its use. The effect of pattern switch code is the opportunity of switching according to DC bus-bar voltage deterministic model. Be that pattern switch code exists two threshold value V_invhAnd V_invl，When DC bus-bar voltage is greater than V_invhTime, inversion rectification module 100 enters inverter mode, when DC bus-bar voltage is less than V_invlTime, inversion rectification module 100 enters rectification pattern. Fig. 5 is the flow chart of pattern switch code 104.

Fig. 3 is accumulator cell charging and discharging module 200 logic diagrams. Comprising power control module 201, DC voltage acquisition module 202 and controller 203. In addition, accumulator cell charging and discharging module 200 also should comprise battery tension acquisition module, input and output protection etc. Wherein power control module is according to the difference of battery tension and capacity and different, and typical case's application is BUCK circuit or BOOST circuit, in the time that electric current is larger, can adopt circuit of synchronous rectification and quasi-resonance circuit to reduce loss, raises the efficiency. The effect of DC voltage acquisition module 202 is the voltage gathering on dc bus, and through proportional amplifier, filtering, the links such as AD conversion are passed to the pattern switch code 2104 in controller DC bus-bar voltage information, for its use. Pattern switch code 204 can be selected corresponding mode of operation according to the magnitude of voltage on the state of battery and dc bus. Fig. 5 is the flow chart of pattern switch code 204.

Fig. 4 is the logic diagram of power optimization module 600. Comprising comprising power control module 601, controller 602 and output voltage current acquisition module 603. In addition, optimize module 600 and also should comprise input voltage acquisition module, input and output protection etc. Wherein power control module 601 is distinguished to some extent according to the output voltage difference of photovoltaic panel, and canonical topology structure is step-up/step-down circuit topology. The effect of output voltage current sample pattern is to give controller output voltage current information, uses for pattern switch code 604. The flow process of pattern switch code is as shown in Figure 7, and its effect is to determine power optimization module 600 work maximum power output pattern, constant voltage mode or constant current stream mode according to output voltage current information.

Claims

1. comprise in a kind of implementation method of direct current power system: inversion rectification module 100, accumulator cell charging and discharging module 200, DC load control module 300, inversion module 400, dc bus 500 and photovoltaic panel are optimized module 600.

2. inversion rectification module 100 according to claim 1, is characterized in that its function comprises power control module 101, DC bus-bar voltage collection module 102, controller 103 and inversion rectification switch code 104.

3. inversion rectification switch code according to claim 2, is characterized in that it exists threshold value V_invhAnd V_invl, when DC bus-bar voltage is greater than V_invhTime, inversion rectification module 100 enters inverter mode, when DC bus-bar voltage is less than V_invlTime, inversion rectification module 100 enters rectification pattern.

4. accumulator cell charging and discharging module 200 according to claim 1, is characterized in that it comprises power control module 201, DC bus-bar voltage collection module 202, controller 203 and discharges and recharges switch code 204.

5. the switch code 204 that discharges and recharges according to claim 4, is characterized in that it exists threshold value V_bathAnd V_batl, when DC bus-bar voltage is greater than V_bathAnd when battery need to charge, accumulator cell charging and discharging module 200 enters charge mode, when DC bus-bar voltage is less than V_batlAnd while having electric energy in battery, accumulator cell charging and discharging module 200 enters discharge mode.

6. photovoltaic panel according to claim 1 is optimized module 600, it is characterized in that its function comprises power control module 601, controller 602 and output voltage current acquisition module 603 and pattern switch code 604.

7. the switch code 604 that discharges and recharges according to claim 6, is characterized in that it exists a threshold voltage V_opthWith a threshold current value I_opth, in the time that output voltage is greater than this value, photovoltaic panel is optimized module 600 and is entered constant voltage pressure output mode, and under this pattern, output voltage is constant in V_opth, output current changes with load variations; When output current is greater than I_opthTime, photovoltaic panel is optimized module 600 and is entered constant current output pattern, and under this pattern, constant output current is at I_opth, output voltage changes with load variations; When its output voltage and output current are less than respectively V_opthAnd I_opthTime, photovoltaic panel is optimized module 600 and is operated in peak power dot pattern, i.e. MPPT pattern.

8. threshold voltage V according to claim 7_opth, it is characterized in that it is the maximum voltage value of described dc bus 500.

9. in direct current power system according to claim 1, it is characterized in that the threshold voltage V in its inversion rectification module 100_invhBe less than the threshold voltage V in its accumulator cell charging and discharging module 200_bath。

10. in direct current power system according to claim 1, it is characterized in that the threshold voltage V in its inversion rectification module 100_invlBe less than the threshold voltage V in its accumulator cell charging and discharging module 200_batl。

11. inversion rectification modules 100 according to claim 1 can install additional as required or remove.

12. accumulator cell charging and discharging modules 200 according to claim 1 can install additional as required or remove.

13. DC load control modules 300 according to claim 1 can install additional as required or remove.

14. inversion modules 400 according to claim 1 can install additional as required or remove.