CN104467005B - The control method of T-shaped three-level three-phase four-bridge arm grid-connected photovoltaic system - Google Patents

The control method of T-shaped three-level three-phase four-bridge arm grid-connected photovoltaic system Download PDF

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CN104467005B
CN104467005B CN201410000258.1A CN201410000258A CN104467005B CN 104467005 B CN104467005 B CN 104467005B CN 201410000258 A CN201410000258 A CN 201410000258A CN 104467005 B CN104467005 B CN 104467005B
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power switch
dc
described
current
switch tube
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CN201410000258.1A
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CN104467005A (en
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杨勇
赵方平
王仁峰
袁其玉
冯洪风
陆永伟
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艾伏新能源科技(上海)股份有限公司
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy
    • Y02E10/56Power conversion electric or electronic aspects
    • Y02E10/563Power conversion electric or electronic aspects for grid-connected applications

Abstract

The invention discloses a kind of three novel level grid-connected systems, mainly include DC dc converter, direct-current-alternating-current converter, photovoltaic array, filter circuit and controller;Described photovoltaic array, controller electrically connect with DC dc converter respectively;The outfan of described DC dc converter electrically connects with the input of direct-current-alternating-current converter;The outfan of described direct-current-alternating-current converter electrically connects with the input of filter circuit circuit;The outfan of described filter circuit is provided with four relays;Described filter circuit input with four relays respectively electrically connects;Each brachium pontis two diodes fewer than the brachium pontis of prior art of the present invention;And use four-wire system connected mode;Meet small hydropower station to not only connecting threephase load but also connecting the requirement of individual event load, also reduce the cost of whole product.

Description

The control method of T-shaped three-level three-phase four-bridge arm grid-connected photovoltaic system

Technical field:

The invention belongs to electric and electronic technical field, particularly to T-shaped three-level three-phase four-bridge arm parallel network power generation The control method of system.

Background technology

Along with lack of energy and environmental pollution are day by day serious, regenerative resource progressively becomes the important composition of human lives Part, this makes solar photovoltaic grid-connection generation technology be rapidly progressed;Photovoltaic generating system is at research photovoltaic Produce on the basis of technology of generating electricity by way of merging two or more grid systems, convert solar energy into electrical energy mainly by photovoltaic battery matrix and be stored into system In ground accumulator or directly for the renewable energy device of load;Photovoltaic generating system generally comprise photovoltaic battery panel, DC-DC converting means, DC-AC converting means, energy storage device, electric energy output transform device (also referred to as inverter), controller Five parts;At present, photovoltaic combining inverter is broadly divided into two types: one is high-power photovoltaic synchronization inverter, mainly should For large-sized photovoltaic power station, connected load mostly is threephase load, and such as three phase electric machine, blower fan, water pump etc., mainly use three The connected mode of three-phase three-wire system;Another kind is small-sized single-phase photovoltaic combining inverter, uses mainly for small home user, is connected The load connect is household electrical appliance etc.;It addition, photovoltaic generating system is also widely used at small-sized photovoltaic power station, particularly power Small-sized photovoltaic power station between 10-50KW, because these small hydropower stations had the most both needed to connect the phase three-wire three such as motor, water pump System load, it is also desirable to connect the single-phase loads such as luminaire, firing equipment, household electrical appliance, only for the angle of load, this Plant small hydropower station and typically require the mode of connection using three-phase four-wire system;

Traditional inverter is mainly two-level inverter, although this inverter provides enough electric energy, but exists because of voltage Too high or electric current rises the shortcoming causing power switch pipe stress difference;For solving these shortcomings, each research and development business develops one after another Three-level inverter, this inverter increases the progression of level output, the step number of output waveform, makes the waveform of output more Close to sinusoidal wave, the harmonic content of generation is few, also reduces the climbing of output voltage simultaneously, reduces switching device pressure The requirement of performance, improves the emi characteristics of inverter;Compared with two-level inverter, identical at output voltage waveforms In the case of, the switching frequency needed for three-level inverter is relatively low, thus the loss of switch is little, efficiency is high;

At present, commercial three-level inverter is mainly diode-clamped three-level inverter, and this clamper type inverter is usual Being made up of three brachium pontis, each brachium pontis is by four diode cooperation, and this reduces the loss of switch in certain degree, Improve the work efficiency of inverter;But for Compact Power Plant, then cannot meet and not only connect threephase load but also connect list , there is certain potential safety hazard in the requirement of item load, therefore for the work characteristics of Compact Power Plant, and a kind of three-phase and four-line of research The photovoltaic generating system of system is referred to as necessity.

Summary of the invention

The load that present invention aims to Compact Power Plant connects feature, it is provided that a kind of simple in construction, T-shaped The grid-connected electric power system of three-phase four-wire system, and provide voltage inversion controlling method for voltage inversion;Both threephase load can have been met Connection requirement can also meet the connection requirement of single-phase load, the safety of system can also be effectively improved simultaneously, widen light The range of application of volt inverter.

For achieving the above object, the present invention adopts the technical scheme that: the present invention T-shaped three-level three-phase four-bridge arm light Photovoltaic grid-connected system, including DC-DC converter (DC-DC converter), direct-current-alternating-current converter (DC-AC changer), Photovoltaic array, filter circuit and controller;(DC-DC converts with DC-DC converter respectively for described photovoltaic array, controller Device) electrical connection;(DC-AC becomes for the outfan of described DC-DC converter (DC-DC converter) and direct-current-alternating-current converter Parallel operation) input electrical connection;The outfan of described direct-current-alternating-current converter (DC-AC changer) and filter circuit circuit Input electrically connects;The outfan of described filter circuit is provided with four relays, respectively S1, S2, S3, S4;Described filtering Circuit input with four relays respectively electrically connects;The outfan of described relay is provided with electrical network ea、eb、ec;Described relay Device S1 and electrical network eaInput electrical connection;Described relay S2 and electrical network ebInput electrical connection;Described relay S3 With electrical network ecInput electrical connection;Described relay S4 respectively with electrical network ea、eb、ecOutfan electrical connection;

Described DC-DC converter includes power switch pipe sd1, power switch pipe sd2, inductance L1, inductance L2, power two Pole pipe D1, power diode D2, electric capacity C1 and electric capacity C2;Described electric capacity C1 and electric capacity C2 forms dc bus filter capacitor Circuit, and on dc bus, form a neutral point O;The negative pole of described electric capacity C1 is connected with the positive electrical of electric capacity C2;Institute The positive pole stating electric capacity C1 connects high level;The negative pole of described electric capacity C2 connects low level;The drain D of described power switch pipe sd1 is divided Do not electrically connect with positive pole, one end of inductance L1 of power diode D1;The negative pole of described power diode D1 connects high level; The other end of described inductance L1 is connected with photovoltaic array;The source S of described power switch pipe sd1 is with power switch pipe sd2's Drain D is connected;The source S of described power switch pipe sd2 respectively with one end, the negative pole of switching diode D2 of inductance L2 Electrical connection;The positive pole of described switching diode D2 connects low level;The other end of described inductance L2 is connected with photovoltaic array;Institute State the grid G of power switch pipe sd1, grid G all skies of power switch pipe sd2 connect;Described power switch pipe sd1 and power On switching tube sd2 the most respectively and connect a diode;Described power switch pipe sd1 and power switch pipe sd2 forms Boost liter Volt circuit;

Described direct-current-alternating-current converter (DC-AC changer) connects the neutral point O with dc bus, is made up of four brachium pontis, Described brachium pontis is respectively the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, four bridge legs;Described first brachium pontis includes power switch pipe Sa1, power switch tube S a2, power switch tube S a3 and power switch tube S a4;The drain D of described power switch tube S a1 connects High level;The source S of described power switch tube S a1 respectively with the drain D of power switch tube S a2, power switch tube S a4 Drain D is connected;The source S of described power switch tube S a2 is connected with the source S of power switch tube S a3;Described power The drain D of switching tube Sa3 connects bus neutral point O;The source S of described power switch tube S a4 connects low level;Described power is opened Close the grid G of pipe Sa1, the grid G of power switch tube S a2, the grid G of power switch tube S a3, power switch tube S a4 Grid G all skies connect;In described power switch tube S a1, power switch tube S a2, power switch tube S a3, power switch tube S a4 The most respectively and connect a diode;Described second brachium pontis includes power switch tube S b1, power switch tube S b2, power switch pipe Sb3 and power switch tube S b4;The drain D of described power switch tube S b1 connects high level;The source electrode of described power switch tube S b1 S is connected with the drain D of power switch tube S b2, the drain D of power switch tube S b4 respectively;Described power switch tube S b2 Source S is connected with the source S of power switch tube S b3;The drain D of described power switch tube S b3 connects bus neutral point O; The source S of described power switch tube S b4 connects low level;The grid G of described power switch tube S b1, power switch tube S b2 Grid G, the grid G of power switch tube S b3, grid G all skies of power switch tube S b4 connect;Described power switch tube S b1, In power switch tube S b2, power switch tube S b3 and power switch tube S b4 the most respectively and connect a diode;Described 3rd bridge Arm includes power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4;Described power switch The drain D of pipe Sc1 connects high level;The source S of described power switch tube S c1 respectively with the drain D of power switch tube S c2, The drain D of power switch tube S c4 is connected;The source S of described power switch tube S c2 and the source S of power switch tube S c3 It is connected;The drain D of described power switch tube S c3 connects bus neutral point O;The source S of described power switch tube S c4 connects low Level;The grid G of described power switch tube S c1, the grid G of power switch tube S c2, the grid G of power switch tube S c3, The grid G of power switch tube S c4 all skies connect;Described power switch tube S c1, power switch tube S c2, power switch tube S c3 and In power switch tube S c4 the most respectively and connect a diode;Described four bridge legs includes power switch tube S d1, power switch pipe Sd2, power switch tube S d3 and power switch tube S d4;The drain D of described power switch tube S d1 connects high level;Described power The source S of switching tube Sd1 is connected with the drain D of power switch tube S d2, the drain D of power switch tube S d4 respectively;Institute The source S of the source S and power switch tube S d3 of stating power switch tube S d2 is connected;The drain electrode of described power switch tube S d3 D connects bus neutral point O;The source S of described power switch tube S d4 connects low level;The grid G of described power switch tube S d1, The grid G of power switch tube S d2, the grid G of power switch tube S d3, grid G all skies of power switch tube S d4 connect;Described In power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4 the most respectively and connect two poles Pipe;

Described filter circuit includes filter inductance L3 and filter capacitor C3;Described filter inductance L3 is made up of four inductance, and point It is not connected with four brachium pontis in direct-current-alternating-current converter (DC-AC changer);Described filter capacitor C3 is by four lotus seed paste Composition;Described four electric capacity one end are in parallel;The other end electrically connects with four inductance respectively;Described filter inductance L3 and filter capacitor C3, for improving the overall filter effect of whole three-phase tri-level four-leg inverter, suppresses current in middle wire switching harmonics, reduces three Total harmonic distortion (THD) value of phase output voltage.

The driving signal complementation driving signal and power switch tube S a3 of described power switch tube S a1, and set simultaneously Put 2us Dead Time;The driving signal complementation driving signal and power switch tube S a4 of power switch tube S a2, and set simultaneously Put 2us Dead Time;The driving signal complementation driving signal and power switch tube S b3 of power switch tube S b1, and set simultaneously Put 2us Dead Time, the driving signal complementation driving signal and power switch tube S b4 of power switch tube S b2, and set simultaneously Put 2us Dead Time;The driving signal complementation driving signal and power switch tube S c3 of power switch tube S c1, and set simultaneously Put 2us Dead Time, the driving signal complementation driving signal and power switch tube S c4 of power switch tube S c2, and set simultaneously Put 2us Dead Time;The driving signal complementation driving signal and power switch tube S n3 of power switch tube S n1, and set simultaneously Put 2us Dead Time, the driving signal complementation driving signal and power switch tube S n4 of power switch tube S n2, and set simultaneously Put 2us Dead Time.

Being mainly used in of described Dead Time prevents switching tube from leading directly to, Dead Time arrange according to switching tube turn on and off time Between determine.

Described controller is MPPT controller;Described MPPT controller is pi controller.

Described four bridge legs is public brachium pontis, for providing path for out-of-balance current or zero-sequence current.

Described first brachium pontis, the second brachium pontis, the 3rd brachium pontis, four bridge legs are equipped with three level brachium pontis midpoints, respectively It is designated as A, B, C, N;Described A, B, C, N 4 is as the output of described direct-current-alternating-current converter (DC-AC changer) End.

The invention still further relates to the control method of T-shaped three-level three-phase four-bridge arm photovoltaic grid-connected inversion electricity generation system, this control Method processed is mainly with digital signal processor TMS320F2808 and CPLD as core, utilizes 12, Pian Nei 16 tunnel AD mould Signal acquisition circuit signal is sampled by block;There is control algolithm to pass through C language write 32-bit numberization and process chip In the program storage of TMS320F2808;

The effect of described digital signal processor CPLD is extension PWM mouth;

Specifically comprise the following steps that

The first step: utilize C language coding to write control program;

Second step: by the program storage controlling program write 32-bit numberization process chip TMS320F2808;

3rd step: start controller, and control the output voltage V of DC-DC converter collection photovoltaic arrayPVWith output electric current IPV

4th step: carry out the conversion of DC-DC according to the switching control method of DC-DC converter, obtain power switch pipe sd1, The driving signal at sd2 two ends;

5th step: by the driving signal input direct-current-AC converter at power switch pipe sd1, sd2 two ends;

6th step: carry out the conversion of DC-AC according to the switching control method of direct-current-alternating-current converter, obtains T-shaped three-phase tri-level The driving signal of four bridge legs.

Described DC-DC converter is for realizing the conversion of DC-DC;The invention still further relates to DC-DC converter Switching control method: the conversion and control of described DC-DC mainly gathers the defeated of photovoltaic array by described DC-DC converter Go out voltage VPVWith output electric current IPV;And obtained the reference voltage of photovoltaic array by maximal power tracing control algolithm after;Pass through again Voltage, the dutycycle of double-closed-loop control Boost circuit of electric current;

Specifically comprise the following steps that

The first step: described DC-DC converter gathers the output voltage V of photovoltaic arrayPVWith output electric current IPV;Through maximum work Rate tracking control algorithm, uses disturbance observational method to obtain the reference voltage V of photovoltaic array in the present inventionref

Second step: the reference voltage V of described photovoltaic arrayrefWith photovoltaic array output voltage VPVThrough calculating, draw voltage difference, And form voltage difference signal;This voltage difference signal is sent into pi controller;Automatic through pi controller Calculate the reference current I of photovoltaic arrayref

3rd step: the reference current I of described photovoltaic arrayrefElectric current I is exported with photovoltaic arrayPVThrough calculating, draw current differential, And form current difference signal;And this current difference signal is sent into pi controller;Work through pi controller With producing control signal;

The voltage signal of photovoltaic array is obtained by voltage sensor, and the current signal of photovoltaic array is obtained by current sensor.

4th step: produced control signal, produces pwm pulse ripple after PWM, is flowed to directly by pwm pulse ripple Power switch pipe sd1 in stream-DC converter and power switch pipe sd2, is used for driving power switch pipe sd1 and power switch Pipe sd2 is operated, and completes the conversion of DC-DC;The driving signal at described power switch pipe sd1 two ends and power switch pipe sd2 The driving signal at two ends is identical.

Described direct-current-alternating-current converter (DC-AC changer), for realizing the conversion of DC-AC, will turn by unidirectional current Change 220V, 50Hz into sinusoidal wave;The invention still further relates to the switching control method of direct-current-alternating-current converter: described DC-AC turns Change and control mainly by the vector controlled of line voltage, mainly use voltage and current double-loop control strategy, line voltage The effect of outer shroud is stable DC busbar voltage;The Main Function of internal ring is, accurate tracking quick to given electric current.

Compared with diode clamp bit-type three level grid-connected system, basis is the brightest to be provided the benefit that: the present invention's is each Brachium pontis two diodes fewer than the brachium pontis of prior art;And four brachium pontis pick out four terminals;Can meet little to the utmost Type power station, to not only connecting threephase load but also connect the requirement of individual event load, also reduces the cost of whole product;Can also have simultaneously Effect ground improves the safety of system, widens the range of application of photovoltaic DC-to-AC converter.

Accompanying drawing explanation

Fig. 1 is the structured flowchart of the present invention;

Fig. 2 is the T-shaped three-phase four-wire system grid-connected photovoltaic system circuit structure diagram of the present invention

Fig. 3 is the control principle drawing of DC-DC converter;

Fig. 4 is the three dimensional vector diagram of grid voltage orientation;

The control principle drawing of Fig. 5 direct-current-alternating-current converter;

Detailed description of the invention

The invention will be further described for the embodiment be given below in conjunction with the accompanying drawings:

As it is shown in figure 1, the present invention T-shaped three-level three-phase four-bridge arm grid-connected photovoltaic system, including DC-to-dc Changer (DC-DC converter), direct-current-alternating-current converter (DC-AC changer), photovoltaic array, filter circuit and control Device;Described photovoltaic array, controller electrically connect with DC-DC converter (DC-DC converter) respectively;Described direct current-straight The outfan of current converter (DC-DC converter) electrically connects with the input of direct-current-alternating-current converter (DC-AC changer); The outfan of described direct-current-alternating-current converter (DC-AC changer) electrically connects with the input of filter circuit circuit;Described filtering The outfan of circuit is provided with four relays, respectively S1, S2, S3, S4;Described filter circuit respectively with four relays Input electrically connects;The outfan of described relay is provided with electrical network ea、eb、ec;Described relay S1 and electrical network eaInput Electrical connection;Described relay S2 and electrical network ebInput electrical connection;Described relay S3 and electrical network ecInput electrical connection; Described relay S4 respectively with electrical network ea、eb、ecOutfan electrical connection;

As in figure 2 it is shown, described DC-DC converter includes power switch pipe sd1, power switch pipe sd2, inductance L1, electricity Sense L2, power diode D1, power diode D2, electric capacity C1 and electric capacity C2;Described electric capacity C1 and electric capacity C2 forms direct current Bus filter-capacitor circuit, and on dc bus, form a neutral point O;The negative pole of described electric capacity C1 is with electric capacity C2 just Pole electrically connects;The positive pole of described electric capacity C1 connects high level;The negative pole of described electric capacity C2 connects low level;Described power switch pipe sd1 Drain D electrically connect with positive pole, one end of inductance L1 of power diode D1 respectively;The negative pole of described power diode D1 is even Connect high level;The other end of described inductance L1 is connected with photovoltaic array;The source S of described power switch pipe sd1 is opened with power The drain D closing pipe sd2 is connected;The source S of described power switch pipe sd2 respectively with one end, the switching diode of inductance L2 The negative electricity of D2 connects;The positive pole of described switching diode D2 connects low level;The other end of described inductance L2 and photovoltaic array phase Connect;The grid G of described power switch pipe sd1, grid G all skies of power switch pipe sd2 connect;Described power switch pipe sd1 With on power switch pipe sd2 the most respectively and connect a diode;Described power switch pipe sd1 and power switch pipe sd2 forms Boost circuit;

As in figure 2 it is shown, described direct-current-alternating-current converter (DC-AC changer) connects the neutral point O with dc bus, by four Individual brachium pontis forms, and described brachium pontis is respectively the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, four bridge legs;Described first brachium pontis bag Include power switch tube S a1, power switch tube S a2, power switch tube S a3 and power switch tube S a4;Described power switch tube S a1 Drain D connect high level;The source S of described power switch tube S a1 drain D, power with power switch tube S a2 respectively is opened The drain D closing pipe Sa4 is connected;The source S of described power switch tube S a2 is connected with the source S of power switch tube S a3; The drain D of described power switch tube S a3 connects bus neutral point O;The source S of described power switch tube S a4 connects low level;Institute State the grid G of power switch tube S a1, the grid G of power switch tube S a2, the grid G of power switch tube S a3, power switch The grid G of pipe Sa4 all skies connect;Described power switch tube S a1, power switch tube S a2, power switch tube S a3, power switch On pipe Sa4 the most respectively and connect a diode;Described second brachium pontis includes power switch tube S b1, power switch tube S b2, power Switching tube Sb3 and power switch tube S b4;The drain D of described power switch tube S b1 connects high level;Described power switch tube S b1 Source S be connected with the drain D of power switch tube S b2, the drain D of power switch tube S b4 respectively;Described power switch The source S of pipe Sb2 is connected with the source S of power switch tube S b3;The drain D of described power switch tube S b3 connects in bus Property point O;The source S of described power switch tube S b4 connects low level;The grid G of described power switch tube S b1, power switch pipe The grid G of Sb2, the grid G of power switch tube S b3, grid G all skies of power switch tube S b4 connect;Described power switch pipe In Sb1, power switch tube S b2, power switch tube S b3 and power switch tube S b4 the most respectively and connect a diode;Described Three brachium pontis include power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4;Described power The drain D of switching tube Sc1 connects high level;The source S of described power switch tube S c1 respectively with the drain electrode of power switch tube S c2 D, the drain D of power switch tube S c4 are connected;The source S of described power switch tube S c2 and the source electrode of power switch tube S c3 S-phase connects;The drain D of described power switch tube S c3 connects bus neutral point O;The source S of described power switch tube S c4 connects low Level;The grid G of described power switch tube S c1, the grid G of power switch tube S c2, the grid G of power switch tube S c3, The grid G of power switch tube S c4 all skies connect;Described power switch tube S c1, power switch tube S c2, power switch tube S c3 and In power switch tube S c4 the most respectively and connect a diode;Described four bridge legs includes power switch tube S d1, power switch pipe Sd2, power switch tube S d3 and power switch tube S d4;The drain D of described power switch tube S d1 connects high level;Described power The source S of switching tube Sd1 is connected with the drain D of power switch tube S d2, the drain D of power switch tube S d4 respectively;Institute The source S of the source S and power switch tube S d3 of stating power switch tube S d2 is connected;The drain electrode of described power switch tube S d3 D connects bus neutral point O;The source S of described power switch tube S d4 connects low level;The grid G of described power switch tube S d1, The grid G of power switch tube S d2, the grid G of power switch tube S d3, grid G all skies of power switch tube S d4 connect;Described In power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4 the most respectively and connect two poles Pipe;

As in figure 2 it is shown, described filter circuit includes filter inductance L3 and filter capacitor C3;Described filter inductance L3 is by four electricity Sense composition, and be connected with four brachium pontis in direct-current-alternating-current converter (DC-AC changer) respectively;Described filter capacitor C3 It is made up of four lotus seed paste;Described four electric capacity one end are in parallel;The other end electrically connects with four inductance respectively;Described filter inductance L3 With filter capacitor C3 for improving the overall filter effect of whole three-phase tri-level four-leg inverter, suppression current in middle wire switch stricture of vagina Ripple, reduces total harmonic distortion (THD) value of three-phase output voltage.

Described first brachium pontis, the second brachium pontis, the 3rd brachium pontis, four bridge legs are equipped with three level brachium pontis midpoints, be designated as respectively A, B, C、N;Described A, B, C, N 4 is as the outfan of described direct-current-alternating-current converter (DC-AC changer).

The invention still further relates to the control method of T-shaped three-level three-phase four-bridge arm photovoltaic grid-connected inversion electricity generation system, this control Method processed is mainly with digital signal processor TMS320F2808 and CPLD as core, utilizes 12, Pian Nei 16 tunnel AD mould Signal acquisition circuit signal is sampled by block;There is control algolithm to pass through C language write 32-bit numberization and process chip In the program storage of TMS320F2808;

The effect of described digital signal processor CPLD is extension PWM mouth;

Specifically comprise the following steps that

The first step: utilize C language coding to write control program;

Second step: by the program storage controlling program write 32-bit numberization process chip TMS320F2808;

3rd step: start controller, and control the output voltage V of DC-DC converter collection photovoltaic arrayPVWith output electric current IPV

4th step: carry out the conversion of DC-DC according to the switching control method of DC-DC converter, obtain power switch pipe sd1, The driving signal at sd2 two ends;

5th step: by the driving signal input direct-current-AC converter at power switch pipe sd1, sd2 two ends;

6th step: carry out the conversion of DC-AC according to the switching control method of direct-current-alternating-current converter, obtains T-shaped three-phase tri-level The driving signal of four bridge legs.

As it is shown on figure 3, described DC-DC converter is for realizing the conversion of DC-DC;The invention still further relates to direct current The switching control method of-DC converter: the conversion and control of described DC-DC is mainly gathered by described DC-DC converter The output voltage V of photovoltaic arrayPVWith output electric current IPV;And the reference electricity of photovoltaic array is obtained by maximal power tracing control algolithm After pressure;Again through overvoltage, the dutycycle of the double-closed-loop control Boost circuit of electric current;

Specifically comprise the following steps that

The first step: described DC-DC converter gathers the output voltage V of photovoltaic arrayPVWith output electric current IPV;Through maximum work Rate tracking control algorithm, uses disturbance observational method to obtain the reference voltage V of photovoltaic array in the present inventionref

Second step: the reference voltage V of described photovoltaic arrayrefWith photovoltaic array output voltage VPVThrough calculating, draw voltage difference, And form voltage difference signal;This voltage difference signal is sent into proportional integral (Proportion Integrate, PI) controller;Warp Cross the reference current I automatically calculating photovoltaic array of pi controllerref

3rd step: the reference current I of described photovoltaic arrayrefElectric current I is exported with photovoltaic arrayPVThrough calculating, draw current differential, And form current difference signal;And this current difference signal is sent into pi controller;Work through pi controller With producing control signal;

4th step: produced control signal, produces pwm pulse ripple after PWM, is flowed to directly by pwm pulse ripple Power switch pipe sd1 in stream-DC converter and power switch pipe sd2, is used for driving power switch pipe sd1 and power switch Pipe sd2 is operated, and completes the conversion of DC-DC;The driving signal at described power switch pipe sd1 two ends and power switch pipe sd2 The driving signal at two ends is identical.

Such as Fig. 4 as it is shown in figure 5, as described in direct-current-alternating-current converter (DC-AC changer) be used for realizing DC-AC Conversion, will unidirectional current to be converted into 220V, 50Hz sinusoidal wave;The invention still further relates to the conversion and control of direct-current-alternating-current converter Method: the conversion and control of described DC-AC, mainly by the vector controlled of line voltage, mainly uses voltage and current pair to close Ring control strategy, the effect of line voltage outer shroud is stable DC busbar voltage;The Main Function of internal ring is fast to given electric current Speed, accurate tracking.

Claims (1)

  1. The control method of 1.T type three-level three-phase four-bridge arm photovoltaic grid-connected inversion electricity generation system, it is characterized in that: described control method is mainly with digital signal processor TMS320F2808 and CPLD as core, utilizes 12, Pian Nei 16 tunnel A/D module to sample signal acquisition circuit signal;By in the control algolithm program storage by C language write 32-bit numberization process chip TMS320F2808;
    The effect of described CPLD is extension PWM mouth;
    Specifically comprise the following steps that
    The first step: utilize C language coding to write control program;
    Second step: by the program storage controlling program write 32-bit numberization process chip TMS320F2808;
    3rd step: start controller, and control the output voltage V of DC-DC converter collection photovoltaic arrayPVWith output electric current IPV
    4th step: carry out the conversion of DC-DC according to the switching control method of DC-DC converter, obtains the driving signal at power switch pipe sd1, sd2 two ends;
    5th step: by the driving signal input direct-current-AC converter at power switch pipe sd1, sd2 two ends;
    6th step: carry out the conversion of DC-AC according to the switching control method of direct-current-alternating-current converter, obtains the driving signal of T-shaped three-phase tri-level four bridge legs;
    The switching control method of described DC-DC converter, mainly gathers the output voltage V of photovoltaic array by described DC-DC converterPVWith output electric current IPV;And obtained the reference voltage of photovoltaic array by maximal power tracing control algolithm after;Again through overvoltage, the dutycycle of the double-closed-loop control Boost circuit of electric current;
    Specifically comprise the following steps that
    The first step: described DC-DC converter gathers the output voltage V of photovoltaic arrayPVWith output electric current IPV;Through maximal power tracing control algolithm, disturbance observational method is used to obtain the reference voltage V of photovoltaic arrayref
    Second step: the reference voltage V of described photovoltaic arrayrefWith photovoltaic array output voltage VPVThrough calculating, draw voltage difference, and form voltage difference signal;This voltage difference signal is sent into the first pi controller;The reference current I automatically calculating photovoltaic array through the first pi controllerref
    3rd step: the reference current I of described photovoltaic arrayrefElectric current I is exported with photovoltaic arrayPVThrough calculating, draw current differential, and form current difference signal;And this current difference signal is sent into the second pi controller;Effect through the second pi controller produces control signal;
    The voltage signal of photovoltaic array is obtained by voltage sensor, and the current signal of photovoltaic array is obtained by current sensor;
    4th step: produced control signal, pwm pulse ripple is produced after PWM, pwm pulse ripple is flowed to the power switch pipe sd1 in DC-DC converter and power switch pipe sd2, is used for driving power switch pipe sd1 and power switch pipe sd2 to be operated, completes the conversion of DC-DC;The driving signal at described power switch pipe sd1 two ends is identical with the driving signal at power switch pipe sd2 two ends.
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CN105099247B (en) * 2015-08-25 2017-07-14 中国矿业大学 The space vector width pulse modulation method of three level four bridge legs current transformers
CN105186899B (en) * 2015-08-31 2018-02-02 苏州大学 A kind of T-shaped three-level three-phase energy storage inverter system
CN105763085B (en) * 2016-03-04 2018-11-20 东南大学 Energy storage grid-connected converter and its control method based on three level of inverse-impedance type
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