CN204809880U - Photovoltaic inverter with alternating current -direct current dynamic adjustment function - Google Patents

Abstract

The utility model belongs to solar photovoltaic power generation sector, concretely relates to photovoltaic inverter with alternating current -direct current dynamic adjustment function. Through the technical scheme of the utility model, in group string data and centralized cost scope basically under the condition of costneutrality to and when having taken into account collecting and distributing formula photovoltaic inverter's advantage, it is interval effectively to improve lower power of exerting oneself, inverter circuit efficiency is lower and the loss is big defect, since the dc -to -ac converter need reach behind certain power that just operation is generated electricity and when the high -power is moved efficiency just can reach more than 97%, the technical scheme of the utility model, can the photovoltaic sooner or later the less time quantum of initial stage period and latter stage generated power make the operation electricity generation in advance that doubles of its electric quantity for the power supply of half dc -to -ac converter through concentrating, be the half dc -to -ac converter moreover in work, the system loss that has significantly reduced effectively solves the consumable electric energy of abandoning electricity and the lower power interval inverter circuit who exerts oneself of reduction of this period, has increased the investment return.

Description

A kind of photovoltaic DC-to-AC converter with alternating current-direct current dynamic adjustments function

Technical field

The invention belongs to solar energy power generating field, be specifically related to a kind of photovoltaic DC-to-AC converter with alternating current-direct current dynamic adjustments function.

Background technology

Along with the continuous progress of solar energy generation technology, photovoltaic generating system is from simple from net light storage inverter all-in-one to centralized grid-connected photovoltaic inverter, along with the continuous expansion of solar power generation scale, the power of centralized inverter also constantly increases, photovoltaic module is connected with centralized inverter with multiple groups of connection in series-parallel, MPPT maximal power tracing is carried out in unification, its system construction is as shown in Fig. 1 (a), the photovoltaic generating system of such 500KW, as long as a 500KW centralized inverter, grid-connected simple cost is low, but, due to the conforming difference of photovoltaic panel product itself and the impact being subject to environment after running, cause the inhomogeneities between group string, have impact on the overall precision of MPPT and the efficiency of photovoltaic generation, and then there is group string inverter, each photovoltaic panel group string inverter, its system construction is as shown in Fig. 1 (b), the overall precision of MPPT and the efficiency of photovoltaic generation can be improved like this, but the photovoltaic generating system of a same 500KW, need 20 25KW group string inverter and connect net, adding the complexity that cost too increases power grid regulation, for above-mentioned technology status, there is again collecting and distributing type inverter, its system construction is as shown in Fig. 1 (c), DC side employing group string data improves the overall precision of MPPT and the efficiency of photovoltaic generation, DC converting becomes to exchange the centralized inversion of employing, combine feature that is centralized and group string data two technical schemes to accept or reject, constitute collecting and distributing type inverter, the efficiency obtaining group string data is lower than group string data cost again.

Above-mentionedly analyze two key factors of photovoltaic DC-to-AC converter in the application of large-scale solar energy electricity generation system, i.e. cost of investment and generating efficiency, can see that the collecting and distributing type inverter technology scheme recently occurred has certain choice flexibility and comprehensive advantage.We need the basis of i.e. equal cost of investment in group string data and centralized cost-range to get on, and research raises the efficiency is more rational.

For the efficiency of grid-connected photovoltaic inverter and the impact of effect, mainly contain three aspects, first DC side MPPT maximal power tracing, the 500KW system effectiveness that centralized photovoltaic DC-to-AC converter is formed can accomplish more than 95.x%, the 500KW system effectiveness that group string data photovoltaic DC-to-AC converter is formed can accomplish more than 97.x%, both difference 2%-3%, for the photovoltaic plant of the operation 10MWp of 25 years, the efficiency of 1% means 337.5 ten thousand yuan of incomes, namely peak light calculates according to by annual 1500 hours, every KWh electricity price is by 0.9 yuan of calculating, then 0.01*1500*25*10000*0.9=3375000 unit,

It two is DC side voltage of converter working ranges, wide ranges can increase generating dutation, more can utilize light application time sooner or later, if photovoltaic generating system can increase the generating being equivalent to 1 minute every day sooner or later, for the photovoltaic plant of the operation 10MWp of 25 years, the generating increasing by 1 minute means increases by 136.88 ten thousand yuan of incomes in power station lifetime, namely peak light calculates according to by annual 1500 hours, every KWh electricity price is by 0.9 yuan of calculating, then 1/60*365*25*10000*0.9=1368750 is first;

It three is optimal output operation intervals of inverter circuit itself, well-known designer can consider to arrange lower power interval of exerting oneself, inverter circuit efficiency is lower, existing centralized, group string data, collecting and distributing type its photovoltaic DC-to-AC converter maximal efficiency of technical scheme all can >=99.x%, and weighting efficiency all can < 97%, this illustrates that lower power interval inverter circuit efficiency of exerting oneself reduces more than 2%; In addition photovoltaic sooner or later initial stage period and latter stage generated output less, the Northwest 07:30 to 09:30 in morning, afternoon 15:30 to 19:30, have more than 4 hours generated outputs to be less than 50% in one day 14 light application time, and inverter after needing to reach certain power just run generating and when high-power operation efficiency just can reach more than 97%.

In sum, the group string inverter of single-stage solves one technical problem, and group string data employing two-stage design cost can be higher; The independent one-level of collecting and distributing type inverter direct-flow side, solves its two technical problem while can solving one technical problem, improve generating efficiency and reduce cost relative to group string inverter simultaneously; But its technical problem of three is not resolved.

Summary of the invention

In order to solve its three technical problem above-mentioned, further raising photovoltaic DC-to-AC converter generating efficiency, the utility model proposes a kind of photovoltaic DC-to-AC converter with alternating current-direct current dynamic adjustments function, comprise the first photovoltaic group serial connection inbound port, second photovoltaic group serial connection inbound port, N photovoltaic group serial connection inbound port, one DC/DC and MPPT module, 2nd DC/DC and MPPT module, NDC/DC and MPPT module, first direct current gating circuit, second direct current gating circuit, N direct current gating circuit, first DC bus, second DC bus, bus, one DC/AC module, 2nd DC/AC module, first exchanges gating circuit, second exchanges gating circuit, main control module, internal electric source, control panel, timing module, exchange connectivity port, it is characterized in that:

Connect first by interchange connectivity port exchange gating circuit and connect a DC/AC module in turn, first DC bus and connect the first direct current gating circuit respectively by the first DC bus, second direct current gating circuit, N direct current gating circuit, a DC/DC and MPPT module and the first photovoltaic group serial connection inbound port is connected in turn respectively again by the first direct current gating circuit, second direct current gating circuit connects the 2nd DC/DC and MPPT module and the second photovoltaic group serial connection inbound port in turn, N direct current gating circuit connects NDC/DC and MPPT module and N photovoltaic group serial connection inbound port in turn, form the first photovoltaic inversion electrical path,

Connect second by interchange connectivity port (12) exchange gating circuit and connect the 2nd DC/AC module in turn, second DC bus and connect the first direct current gating circuit respectively by the second DC bus, second direct current gating circuit, N direct current gating circuit, a DC/DC and MPPT module and the first photovoltaic group serial connection inbound port is connected in turn respectively again by the first direct current gating circuit, second direct current gating circuit connects the 2nd DC/DC and MPPT module and the second photovoltaic group serial connection inbound port in turn, N direct current gating circuit connects NDC/DC and MPPT module and N photovoltaic group serial connection inbound port in turn, form the second photovoltaic inversion electrical path,

Main control module and control panel be connected with timing module and be connected a DC/DC and MPPT module respectively by bus, the 2nd DC/DC and MPPT module, NDC/DC and MPPT module, the first direct current gating circuit, the second direct current gating circuit, N direct current gating circuit, a DC/AC module, the 2nd DC/AC module, first exchange gating circuit, second and exchange gating circuit, forms Inversion Control System link;

Internal electric source connects the first DC bus, the second DC bus and main control module respectively, forms inversion system internal power path.

To be multiple DC/DC and MPPT module (2n) corresponding with the photovoltaic group string accessed with photovoltaic group serial connection inbound port (1n) and the rated power sum of a rated power sum≤DC/AC module of multiple DC/DC and MPPT module (2n) and the 2nd DC/AC module for a kind of technical scheme with the photovoltaic DC-to-AC converter of alternating current-direct current dynamic adjustments function of the utility model; Main control module judges the photovoltaic generation time period according to timing module data, and the generated output sum of multiple DC/DC and the MPPT module of comparison, when the rated power sum of the generated output sum≤DC/AC module (6a) of multiple DC/DC and MPPT module and the 2nd DC/AC module, main control module selects one of the first photovoltaic inversion electrical path or the second photovoltaic inversion electrical path conducting controlling normally to run to run according to status of equipment; Otherwise the first photovoltaic inversion electrical path that master control module controls can normally be run and the conducting simultaneously of the second photovoltaic inversion electrical path run.

By a kind of technical scheme with the photovoltaic DC-to-AC converter of alternating current-direct current dynamic adjustments function of the utility model, effectively can improve lower power interval of exerting oneself, the defect that inverter circuit efficiency is lower, and can sooner or later initial stage period and generated output less time period in latter stage run generating in advance at photovoltaic, effectively solve this period abandon electricity and reduce lower power interval inverter circuit of exerting oneself from consuming electric power.

Accompanying drawing explanation

Fig. 1 is the system construction principle schematic of prior art photovoltaic DC-to-AC converter.

Fig. 2 is a kind of system construction principle schematic with the photovoltaic DC-to-AC converter of alternating current-direct current dynamic adjustments function.

Embodiment

As examples of implementation, by reference to the accompanying drawings a kind of photovoltaic DC-to-AC converter with alternating current-direct current dynamic adjustments function of the present utility model is described, but technology of the present utility model and scheme are not limited to the content that the present embodiment provides.

Drawings illustrate a kind of system construction principle schematic with the photovoltaic DC-to-AC converter of alternating current-direct current dynamic adjustments function.Shown in accompanying drawing, a kind of photovoltaic DC-to-AC converter with alternating current-direct current dynamic adjustments function that the utility model proposes, comprise the first photovoltaic group serial connection inbound port (1a), second photovoltaic group serial connection inbound port (1b), N photovoltaic group serial connection inbound port (1n), one DC/DC and MPPT module (2a), 2nd DC/DC and MPPT module (2b), NDC/DC and MPPT module (2n), first direct current gating circuit (3a), second direct current gating circuit (3b), N direct current gating circuit (3n), first DC bus (4a), second DC bus (4b), bus (5), one DC/AC module (6a), 2nd DC/AC module (6b), first exchanges gating circuit (7a), second exchanges gating circuit (7b), main control module (8), internal electric source (9), control panel (10), timing module (11), exchange connectivity port (11), it is characterized in that:

Connect first by interchange connectivity port (12) exchange gating circuit (7a) and connect a DC/AC module (6a) in turn, first DC bus (4a) and connect the first direct current gating circuit (3a) respectively by the first DC bus (4a), second direct current gating circuit (3b), N direct current gating circuit (3n), a DC/DC and MPPT module (2a) and the first photovoltaic group serial connection inbound port (1a) is connected in turn respectively again by the first direct current gating circuit (3a), second direct current gating circuit (3b) connects the 2nd DC/DC and MPPT module (2b) and the second photovoltaic group serial connection inbound port (1b) in turn, N direct current gating circuit (3n) connects NDC/DC and MPPT module (2n) and N photovoltaic group serial connection inbound port (1n) in turn, form the first photovoltaic inversion electrical path,

Connect second by interchange connectivity port (12) exchange gating circuit (7b) and connect the 2nd DC/AC module (6b) in turn, second DC bus (4a) and connect the first direct current gating circuit (3a) respectively by the second DC bus (4b), second direct current gating circuit (3b), N direct current gating circuit (3n), a DC/DC and MPPT module (2a) and the first photovoltaic group serial connection inbound port (1a) is connected in turn respectively again by the first direct current gating circuit (3a), second direct current gating circuit (3b) connects the 2nd DC/DC and MPPT module (2b) and the second photovoltaic group serial connection inbound port (1b) in turn, N direct current gating circuit (3n) connects NDC/DC and MPPT module (2n) and N photovoltaic group serial connection inbound port (1n) in turn, form the second photovoltaic inversion electrical path,

Main control module (8) and control panel (10) are connected with timing module (11) and are connected a DC/DC and MPPT module (2a) respectively by bus (5), 2nd DC/DC and MPPT module (2b), NDC/DC and MPPT module (2n), first direct current gating circuit (3a), second direct current gating circuit (3b), N direct current gating circuit (3n), one DC/AC module (6a), 2nd DC/AC module (6b), first exchanges gating circuit (7a), second exchanges gating circuit (7b), form Inversion Control System link,

Internal electric source (9) connects the first DC bus (4a), the second DC bus (4b) and main control module (8) respectively, forms inversion system internal power path.

To be multiple DC/DC and MPPT module (2n) corresponding with the photovoltaic group string accessed with photovoltaic group serial connection inbound port (1n) and the rated power sum of the rated power sum of multiple DC/DC and MPPT module (2n)≤DC/AC module (6a) and the 2nd DC/AC module (6b) for a kind of technical scheme with the photovoltaic DC-to-AC converter of alternating current-direct current dynamic adjustments function of the utility model; Main control module (8) judges the photovoltaic generation time period according to timing module (11) data, and the generated output sum of multiple DC/DC and the MPPT module (2n) of comparison, when the rated power sum of the generated output sum≤DC/AC module (6a) of multiple DC/DC and MPPT module (2n) and the 2nd DC/AC module (6b), main control module (8) selects one of the first photovoltaic inversion electrical path or the second photovoltaic inversion electrical path conducting controlling normally to run to run according to status of equipment; Otherwise main control module (8) controls the first photovoltaic inversion electrical path that can normally run and the conducting simultaneously of the second photovoltaic inversion electrical path runs.

By a kind of technical scheme with the photovoltaic DC-to-AC converter of alternating current-direct current dynamic adjustments function of the utility model, when cost does not increase substantially, while having taken into account the advantage of collecting and distributing type photovoltaic DC-to-AC converter, effectively can improve lower power interval of exerting oneself, the defect that inverter circuit efficiency is lower; The Northwest 07:30 to 09:30 in morning, afternoon 15:30 to 19:30, have more than 4 hours generated outputs to be less than 50% in one day 14 light application time, and inverter just run generating after needing to reach certain power and efficiency could greatly more than 97% when high-power operation; The utility model can sooner or later initial stage period and generated output less time period in latter stage run generating in advance at photovoltaic, and be that 1/2nd inverters are in work, greatly reduce system loss, effective this period of solution abandon electricity and reduce lower power interval inverter circuit of exerting oneself from consuming electric power, add investment return.

Claims (1)

1. one kind has the photovoltaic DC-to-AC converter of alternating current-direct current dynamic adjustments function, comprise the first photovoltaic group serial connection inbound port (1a), second photovoltaic group serial connection inbound port (1b), N photovoltaic group serial connection inbound port (1n), one DC/DC and MPPT module (2a), 2nd DC/DC and MPPT module (2b), NDC/DC and MPPT module (2n), first direct current gating circuit (3a), second direct current gating circuit (3b), N direct current gating circuit (3n), first DC bus (4a), second DC bus (4b), bus (5), one DC/AC module (6a), 2nd DC/AC module (6b), first exchanges gating circuit (7a), second exchanges gating circuit (7b), main control module (8), internal electric source (9), control panel (10), timing module (11), exchange connectivity port (11), it is characterized in that:

Connect first by interchange connectivity port (12) exchange gating circuit (7a) and connect a DC/AC module (6a) in turn, first DC bus (4a) and connect the first direct current gating circuit (3a) respectively by the first DC bus (4a), second direct current gating circuit (3b), N direct current gating circuit (3n), a DC/DC and MPPT module (2a) and the first photovoltaic group serial connection inbound port (1a) is connected in turn respectively again by the first direct current gating circuit (3a), second direct current gating circuit (3b) connects the 2nd DC/DC and MPPT module (2b) and the second photovoltaic group serial connection inbound port (1b) in turn, N direct current gating circuit (3n) connects NDC/DC and MPPT module (2n) and N photovoltaic group serial connection inbound port (1n) in turn, form the first photovoltaic inversion electrical path,

Connect second by interchange connectivity port (12) exchange gating circuit (7b) and connect the 2nd DC/AC module (6b) in turn, second DC bus (4a) and connect the first direct current gating circuit (3a) respectively by the second DC bus (4b), second direct current gating circuit (3b), N direct current gating circuit (3n), a DC/DC and MPPT module (2a) and the first photovoltaic group serial connection inbound port (1a) is connected in turn respectively again by the first direct current gating circuit (3a), second direct current gating circuit (3b) connects the 2nd DC/DC and MPPT module (2b) and the second photovoltaic group serial connection inbound port (1b) in turn, N direct current gating circuit (3n) connects NDC/DC and MPPT module (2n) and N photovoltaic group serial connection inbound port (1n) in turn, form the second photovoltaic inversion electrical path,

Main control module (8) and control panel (10) are connected with timing module (11) and are connected a DC/DC and MPPT module (2a) respectively by bus (5), 2nd DC/DC and MPPT module (2b), NDC/DC and MPPT module (2n), first direct current gating circuit (3a), second direct current gating circuit (3b), N direct current gating circuit (3n), one DC/AC module (6a), 2nd DC/AC module (6b), first exchanges gating circuit (7a), second exchanges gating circuit (7b), form Inversion Control System link,

Internal electric source (9) connects the first DC bus (4a), the second DC bus (4b) and main control module (8) respectively, forms inversion system internal power path.