CN203707804U - Three-phase cascade multi-level photovoltaic inverter and control system thereof - Google Patents

Three-phase cascade multi-level photovoltaic inverter and control system thereof Download PDF

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Publication number
CN203707804U
CN203707804U CN201320718840.2U CN201320718840U CN203707804U CN 203707804 U CN203707804 U CN 203707804U CN 201320718840 U CN201320718840 U CN 201320718840U CN 203707804 U CN203707804 U CN 203707804U
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China
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control system
module
controller
sub
level photovoltaic
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Expired - Fee Related
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CN201320718840.2U
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Chinese (zh)
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李泽军
王翠
曾利军
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Hunan Institute of Technology
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Hunan Institute of Technology
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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

Abstract

The utility model discloses a three-phase cascade multi-level photovoltaic inverter and a control system thereof. The three-phase cascade multi-level photovoltaic inverter comprises 3n PV arrays, 3n DC-DC modules, 3n DC-AC modules and the control system. The control system comprises a main controller, a communication unit, n sub-controllers, n first drivers, and n second drivers. The communication unit comprises n+1 electro-optical conversion modules, a first optical fiber coupler, n+1 photoelectric conversion modules, and a second optical fiber coupler. In the three-phase cascade multi-level photovoltaic inverter, an equal-voltage cascade inversion circuit is composed of a plurality of inverters, the current and voltage taken by switches of each level are low, so that convenient element choosing, low price, no voltage equalization and current equalization requirements, capability in employing an n+1 redundant design scheme, and improvement is circuit reliability and stability are achieved. The three-phase cascade multi-level photovoltaic inverter is simple in structure, convenient to operate, and high in energy utilization rate.

Description

Three-phase cascade connection multi-level photovoltaic DC-to-AC converter and control system thereof
Affiliated technical field
The utility model relates to photovoltaic reverse power generation device field, refers in particular to a kind of three-phase cascade connection multi-level photovoltaic DC-to-AC converter and control system thereof that photo-voltaic power generation station uses of specializing in.
Background technology
Along with the development of human society, the consumption of the energy constantly increases, and fossil energy in the world will reach capacity one day.Meanwhile, due to a large amount of burning fossil energies, the biological environment in the whole world goes from bad to worse, and the mankind's survival and development have been formed to very large threat.Under such background, solar energy, as a kind of regenerative resource of flood tide, has caused people's great attention, and national governments are progressively promoting the development of solar energy power generating industry.
Three-phase cascading multiple electrical level photovoltaic DC-to-AC converter and control system thereof adopt the connection in series-parallel of some photovoltaic battery panels to obtain independently direct voltage source, utilize control system to control independent DC power supply, make each DC power output voltage equal and opposite in direction, and each independently direct voltage source is carried out to inversion, then inverting output terminal series connection can be met to electrical network required voltage.Three-phase cascade connection multi-level photovoltaic DC-to-AC converter and control system thereof can independently be controlled the power stage of each unit, make in photovoltaic inverting system cell panel be operated in also can to carry out independently MPPT maximum power point tracking (Maximum Power Point Tracking is called for short mppt) under unmatched state to control.Three-phase cascade connection multi-level photovoltaic DC-to-AC converter and control system thereof can obtain satisfied output effect in the situation that switching frequency is lower, not only reduce switching loss, reduce filter volume, saved filter cost, effectively improved the efficiency of power conversion system simultaneously.The redundancy properties of three-phase cascade connection multi-level photovoltaic DC-to-AC converter and control system thereof, can overcome because intensity of illumination weakens the output voltage causing and reduce, and the excursion of output voltage amplitude is reduced, and output voltage waveforms quality improves.
Utility model content
The technical problems to be solved in the utility model is: the technical problem existing for prior art, the utility model proposes a kind of simple in structure, with low cost, adopt cascade inverter circuit improving output voltage and power, each inverter bridge of series connection is adopted three-phase cascade connection multi-level photovoltaic DC-to-AC converter and the control system thereof of distributed computer control simultaneously.
In order to solve the problems of the technologies described above, the solution the utility model proposes is: three-phase cascade connection multi-level photovoltaic DC-to-AC converter and control system thereof, it is characterized in that: each includes n PV array (being photovoltaic battery array) mutually the main circuit of three-phase cascade connection multi-level photovoltaic DC-to-AC converter, n DC-DC module, n DC-AC module, described PV array is for generation of DC power supply, DC-DC module realizes DC voltage conversion and MPPT maximum power point tracking control (being that mppt controls), DC-AC module realizes invert function, described PV array output dc voltage after capacitor filtering as the power supply of DC-DC module, DC-DC module is controlled by control system, realizing mppt controls, and the output voltage that guarantees each DC-DC module equates, meet the supply voltage requirement that waits voltage cascaded multilevel inverter, DC-DC module output voltage after capacitor filtering as the power supply of DC-AC module, DC-AC module is controlled by control system, the output series connection of multiple DC-AC modules, after inductor filter, export.Each phase main circuit structure of three-phase inverter is in full accord, and output Y shape connects.
Described control system comprises master controller, communication unit, multiple sub-controller and driver, master controller is connected with the input of each sub-controller by communication unit, the output of sub-controller is connected with driver, driver comprises driver one and driver two, driver one is connected with DC-DC module, control for the voltage transformation and the mppt that realize DC-DC module, driver two is connected with DC-AC module, for realizing the inversion of DC-AC module.
Described master controller and sub-controller form two-stage distributed computer control system, utilize mains voltage signal realize the synchronous of each series inverter and coordinate.
Compared with prior art, the utility model has the advantage of:
1, the utility model adopts the voltage cascade inverter circuits such as multiple inverter compositions, electric current and voltage strength that the switching device of every grade bears are low, not only the selection of components and parts is convenient but also cheap, without all requirements of pressure, current-sharing, the damage of any one-level can not affect the work of other grade, n+1 backup scheme be can adopt easily, circuit reliability and stability improved;
2, the utility model can be realized the mppt control of each PV array, and the conversion efficiency of direct voltage is high;
3, control system of the present utility model adopts the design of a master controller and multiple sub-controllers, makes photovoltaic inverting system become a distributed computer control system, adopts optical fiber communication between master controller and multiple sub-controller simultaneously;
4, the utility model adopts mains voltage signal to realize the synchronous and coordination between each DC-AC module, need not control in real time the waveform of inverter, thereby reduce the requirement to communicating circuit capacity, improved the reliability of control system, saved cost.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the utility model is further illustrated.
Fig. 1 is structural framing schematic diagram of the present utility model;
Fig. 2 is control system frame structure schematic diagram of the present utility model;
Fig. 3 is the main circuit structure figure of the utility model A phase;
Fig. 4 is specific embodiment of the utility model.
Marginal data
1, PV array 2, DC-DC module 3, DC-AC module
4, control system 41, master controller 42, communication unit
43, sub-controller 44, driver 1, driver two
Symbol description
C a1, C a2, C a3, C an, C a1', C a2', C a3', C an': A phase filter capacitor
C b1, C b2, C b3, C bn, C b1', C b2', C b3', C bn': B phase filter capacitor
C c1, C c2, C c3, C cn, C c1', C c2', C c3, C cn': C phase filter capacitor
Q a1、Q a2、Q an、Q 11、Q 12、Q 13、Q 14、Q 21、Q 22、Q 23、Q 24、Q n1、Q n2、Q n3、Q n4：IGBT
L a, L b, L c: filter inductance L a1, L a2, L an: energy storage inductor
D a1, D a2, D an: diode
Embodiment
Below with reference to the drawings and specific embodiments, the utility model is described in further details.
As shown in Figure 1, three-phase cascade connection multi-level photovoltaic DC-to-AC converter of the present utility model and control system thereof, it comprises 3n PV array (1), 3n DC-DC module (2), 3n DC-AC module (3), control system (4), described control system (4) is by master controller (41), communication unit (42), n sub-controller (43), n driver one (44) and n driver two (45) compositions, PV array (1) output voltage is connected with DC-DC module (2) respectively after capacitor filtering, DC-DC module (2) output voltage is connected with DC-AC module (3) respectively after capacitor filtering, the n of each phase DC-AC module (3) output is connected successively, through inductance L xafter (x is A, B, C) filtering, be connected the mid point that N is three-phase with electrical network from A, B, C end output voltage.
Shown in Figure 2, control system (4) comprises master controller (41), communication unit (42) and n sub-controller (43), n driver one (44) and n driver two (45), master controller (41) is connected with the input of the sub-controller (43) of n by communication unit (42), the output of sub-controller (43) is connected with n driver two (45) with n driver one (44), a driver two (45) connects the switching device of 3 the DC-DC modules (2) in three-phase inverter same position, the output signal of n driver two (45) is directly received the gate pole of the switching device of 3n DC-DC module (2), a driver one (44) connects the switching device of 3 the DC-AC modules (3) in three-phase inverter same position, the output signal of n driver one (44) is directly received the gate pole of each switching device of 3n DC-AC module (3).
Referring to Fig. 3, A phase main circuit is made up of n PV array (1), a n DC-DC module (2), a n DC-AC module (3), and each DC-DC module (2) is by a switching device Q ai(i gets 1,2 ..., n) and inductance L ai(i gets 1,2 ..., n) and diode D ai(i gets 1,2 ..., n) composition, each DC-AC module (3) is by four switching device Q i1, Q i2, Q i3, Q i4(i gets 1,2 ..., n), composition, output inductance L strobes.Other two-phase main circuits of three-phase inverter are in full accord with A phase main circuit.
Shown in Figure 4, the main circuit of the present embodiment has 9 PV arrays (1), 9 DC-DC modules (2), 9 DC-AC modules (3), and each is composed in series three-phase three-stage inverter by the output of 3 DC-AC modules (3).In the present embodiment, communication unit (42) adopts optical fiber communication, and master controller (41) and sub-controller (43) all adopt take TMS320F240 as basic Embedded computer system unit.In the present embodiment, this control system (4) is made up of 1 master controller (41), 1 communication unit (42) and 3 sub-controllers (43) and one (44), 3 driver two (45) of 3 drivers; 3 DC-DC modules (2) of the same stages of A, B, C three-phase and corresponding DC-AC module (3) thereof share an independently sub-controller (43), it act as the control and protection of realizing DC-DC module (2) and DC-AC module (3), produce the driving signal of each switching device, sub-controller (43) detects input voltage signal and the output current signal of DC-DC module (2) and for realizing, the mppt of PV array (1) is controlled; The function of master controller (41) is the synchronous working that regulates, protects and realize each DC-AC module (3).DC-AC module (3) voltage over the ground floats, therefore, sub-controller (43) mutually between and they on electric, isolate over the ground, between master controller (41) and sub-controller (43), adopt optical-fibre communications or photoelectricity to isolate.Sub-controller (43) and master controller (41) are all take TMS320F240 as basic Embedded computer system unit, and they form respectively the master computer control of the 1st grade and the distributed computer control of the 2nd grade.
When work, the advanced row data processing of master controller (41) of the 1st grade, control signal is delivered to respectively to the sub-controller (43) that is positioned at the 2nd grade by the optical-fibre communications of communication unit (42) again, sub-controller (43) is according to the control signal of master controller (41), control respectively DC-DC module (2) and DC-AC module (3), the output series winding of DC-AC module (3), through inductance L a, L b, L cafter filtering, be connected in A, B, the C phase line of three-phase, the mid point of Y shape is N.At work, sub-controller (43) detects input voltage and the output current of DC-DC module (2) and realizes the mppt control to PV array (1), master controller (41) is by detecting voltage feedback signal and the line voltage parameter of inverter, transmit control signal to each sub-controller (43), each sub-controller (43) is adjusted the operating state of corresponding DC-DC module (2) and DC-AC module (3).Fault-signal from DC-DC module (2) and DC-AC module (3) is delivered to master controller (41) by sub-controller (43) respectively.
These are only an embodiment of the present utility model, the utility model is not limited to above-described embodiment, as long as belong to the technical scheme under the utility model design, all should belong to protection range of the present utility model.

Claims (2)

1. three-phase cascade connection multi-level photovoltaic DC-to-AC converter and control system thereof, it is characterized in that: it comprises 3n PV array (1), a 3n DC-DC module (2), a 3n DC-AC module (3), control system (4), and described control system (4) is made up of master controller (41), communication unit (42), a n sub-controller (43), a n driver one (44) and n driver two (45); Described sub-controller (43) is connected with driver one (44), and the driving signal of generation is used for controlling DC-DC module (2); Described sub-controller (43) is connected with driver two (45), and the driving signal of generation is used for controlling DC-AC module (3); Described communication unit (42) adopts optical fiber communication, comprise n+1 electrooptic conversion module (421), fiber coupler one (422), a n+1 photoelectric conversion module (423) and fiber coupler two (424), the control signal that master controller (41) produces is sent to each sub-controller (43) by communication unit (42), and each sub-controller (43) is sent master controller (41) fault-signal back to by communication unit (42).
2. three-phase cascade connection multi-level photovoltaic DC-to-AC converter according to claim 1 and control system thereof, it is characterized in that: described master controller (41) and sub-controller (43) form two-stage distributed control system, utilize mains voltage signal realize the synchronous of each DC-AC module and coordinate.
CN201320718840.2U 2013-11-08 2013-11-08 Three-phase cascade multi-level photovoltaic inverter and control system thereof Expired - Fee Related CN203707804U (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104467006A (en) * 2014-04-18 2015-03-25 南昌工程学院 Control system for three-phase cascaded multilevel photovoltaic grid-connected inverter
CN104684211A (en) * 2015-01-27 2015-06-03 中冶华天工程技术有限公司 Centralized control modular power electronic road illumination energy-saving device
CN112542883A (en) * 2019-09-20 2021-03-23 台达电子工业股份有限公司 Power system with communication function for solid-state transformer structure and communication module
CN113906645A (en) * 2019-03-29 2022-01-07 阿尔法能源技术公司 Module-based energy system capable of cascade and interconnection configuration and related method thereof

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104467006A (en) * 2014-04-18 2015-03-25 南昌工程学院 Control system for three-phase cascaded multilevel photovoltaic grid-connected inverter
CN104467006B (en) * 2014-04-18 2019-05-14 南昌工程学院 The cascade multilevel photovoltaic grid-connected inverter control system of three-phase
CN104684211A (en) * 2015-01-27 2015-06-03 中冶华天工程技术有限公司 Centralized control modular power electronic road illumination energy-saving device
CN113906645A (en) * 2019-03-29 2022-01-07 阿尔法能源技术公司 Module-based energy system capable of cascade and interconnection configuration and related method thereof
CN112542883A (en) * 2019-09-20 2021-03-23 台达电子工业股份有限公司 Power system with communication function for solid-state transformer structure and communication module
CN112542883B (en) * 2019-09-20 2023-11-14 台达电子工业股份有限公司 Power system with communication function for solid-state transformer structure and communication module

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Granted publication date: 20140709

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