CN203674732U - T-type three-level three-phase four-leg photovoltaic gird-connected power generation system - Google Patents
T-type three-level three-phase four-leg photovoltaic gird-connected power generation system Download PDFInfo
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- CN203674732U CN203674732U CN201420000373.4U CN201420000373U CN203674732U CN 203674732 U CN203674732 U CN 203674732U CN 201420000373 U CN201420000373 U CN 201420000373U CN 203674732 U CN203674732 U CN 203674732U
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Abstract
The utility model discloses a T-type three-level three-phase four-leg photovoltaic grid-connected power generation system. The T-type three-level three-phase four-leg photovoltaic grid-connected power generation system comprises a DC-DC converter, a DC-AC converter, a photovoltaic array, a filter circuit and a controller, the photovoltaic array and the controller are respectively and electrically connected with the DC-DC converter, an output terminal of the DC-DC converter is electrically connected with an input terminal of the DC-A converter, an output terminal of the DC-AC converter is electrically connected with an input terminal of the filter circuit, an output terminal of the filter circuit is provided with four relays, and the filter circuit is respectively and electrically connected with input terminals of the four relays. According to the T-type three-level three-phase four-leg photovoltaic grid-connected power generation system, compared with the prior art, each leg has two less diodes, and a four-wire system connecting mode is adopted so that the requirements of connecting a three-phase load and a single load of a small-scale power station are satisfied, and the cost of the whole product is reduced.
Description
Technical field
The utility model belongs to electric and electronic technical field, particularly T-shaped three level three-phase four-arm grid-connected photovoltaic systems.
Background technology
Along with lack of energy and environmental pollution day by day serious, regenerative resource progressively becomes human lives's important component part, this is developed solar photovoltaic grid-connection generation technology fast; Photovoltaic generating system is to produce on the basis of research solar photovoltaic grid-connection generation technology, is mainly utilize photovoltaic battery matrix to convert solar energy into electrical energy and be stored in storage battery systematically or directly for the renewable energy device of load; Photovoltaic generating system generally comprises 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 mainly divided into two types: one is high-power photovoltaic synchronization inverter, is mainly used in large-sized photovoltaic power station, connect load and mostly be threephase load, such as three phase electric machine, blower fan, water pump etc., mainly adopt the connected mode of three-phase three-wire system; Another kind is small-sized single-phase photovoltaic combining inverter, and mainly for small home user, the load connecting is household electrical appliance etc.; In addition, photovoltaic generating system is also widely used at small-sized photovoltaic power station, the particularly small-sized photovoltaic power station of power between 10-50KW, because these small hydropower stations had both needed to connect the load of the three-phase three-wire system such as motor, water pump conventionally, also need to connect the single-phase loads such as lighting apparatus, firing equipment, household electrical appliance, only, from the angle of load, this small hydropower station need to adopt the mode of connection of three-phase four-wire system conventionally;
Traditional inverter is mainly two-level inverter, although this inverter provides enough electric energy, has the shortcoming that causes power switch pipe stress difference because of overtension or Current rise; For solving these shortcomings, each research and development business has developed three-level inverter one after another, this inverter increases the progression of level output, the step number of output waveform, make the waveform of output more approach sinusoidal wave, the harmonic content producing is few, also the climbing that has reduced output voltage, has reduced the requirement to switch device withstand voltage performance simultaneously, has improved the emi characteristics of inverter; Compared with two-level inverter, in the situation that output voltage waveforms is identical, the required switching frequency of three-level inverter is lower, thereby the loss of switch is little, efficiency is high;
At present, commercial three-level inverter is mainly diode clamp type three-level inverter, and this clamper type inverter is made up of three brachium pontis conventionally, and each brachium pontis is by four diode co-operation, the loss that this has reduced switch in certain degree, has improved the operating efficiency of inverter; But for Compact Power Plant, cannot meet the requirement that not only connects threephase load but also connect individual event load, have certain potential safety hazard, therefore for the work characteristics of Compact Power Plant, the photovoltaic generating system of studying a kind of three-phase four-wire system is called necessity.
Summary of the invention
The purpose of this utility model is to connect feature for the load of Compact Power Plant, a kind of grid-connected electric power system of simple in structure, T-shaped three-phase four-wire system is provided, the connection requirement that both can meet threephase load also can meet the connection requirement of single-phase load, the fail safe that simultaneously can also effectively improve system, widens the range of application of photovoltaic DC-to-AC converter.
For achieving the above object, the technical scheme that the utility model is taked is: the T-shaped three level three-phase four-arm grid-connected photovoltaic systems of the utility model, comprise DC-DC converter (DC-DC converter), direct-current-alternating-current converter (DC-AC converter), photovoltaic array, filter circuit and controller; Described photovoltaic array, controller are electrically connected with DC-DC converter (DC-DC converter) respectively; The output of described DC-DC converter (DC-DC converter) is electrically connected with the input of direct-current-alternating-current converter (DC-AC converter); The output of described direct-current-alternating-current converter (DC-AC converter) is electrically connected with the input of filter circuit circuit; The output of described filter circuit is provided with four relays, is respectively S1, S2, S3, S4; Described filter circuit is electrically connected with the input of four relays respectively; The output of described relay is provided with electrical network e
a, e
b, e
c; Described relay S1 and electrical network e
ainput electrical connection; Described relay S2 and electrical network e
binput electrical connection; Described relay S3 and electrical network e
cinput electrical connection; Described relay S4 respectively with electrical network e
a, e
b, e
coutput electrical connection;
Described DC-DC converter comprises power switch pipe sd1, power switch pipe sd2, inductance L 1, inductance L 2, power diode D1, power diode D2, capacitor C 1 and capacitor C 2; Described capacitor C 1 and capacitor C 2 form DC bus filter-capacitor circuit, and on DC bus, form a neutral point O; The negative pole of described capacitor C 1 is electrically connected with the positive pole of capacitor C 2; The positive pole of described capacitor C 1 connects high level; The negative pole of described capacitor C 2 connects low level; The drain D of described power switch pipe sd1 is electrically connected with the positive pole of power diode D1, one end of inductance L 1 respectively; The negative pole of described power diode D1 connects high level; The other end of described inductance L 1 is connected with photovoltaic array; The source S of described power switch pipe sd1 is connected with the drain D of power switch pipe sd2; The source S of described power switch pipe sd2 is connected with one end of inductance L 2, the negative electricity of switching diode D2 respectively; The positive pole of described switching diode D2 connects low level; The other end of described inductance L 2 is connected with photovoltaic array; The grid G of described power switch pipe sd1, the equal sky of grid G of power switch pipe sd2 connect; On described power switch pipe sd1 and power switch pipe sd2 also respectively and connect a diode; Described power switch pipe sd1 and power switch pipe sd2 composition Boost booster circuit;
Described direct-current-alternating-current converter (DC-AC converter) connects the neutral point O with DC bus, is made up of four brachium pontis, and described brachium pontis is respectively the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, the 4th brachium pontis; Described the first brachium pontis comprises power switch tube S a1, 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 is connected with the drain D of power switch tube S a2, the drain D of power switch tube S a4 respectively; 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; The grid G of the grid G of described power switch tube S a1, the grid G of power switch tube S a2, power switch tube S a3, the equal sky of grid G of power switch tube S a4 connect; On described power switch tube S a1, power switch tube S a2, power switch tube S a3, power switch tube S a4 also respectively and connect a diode; Described the second brachium pontis comprises power switch tube S b1, power switch tube S b2, power switch tube S b3 and power switch tube S b4; The drain D of described power switch tube S b1 connects high level; The source S of described power switch tube S b1 is connected with the drain D of power switch tube S b2, the drain D of power switch tube S b4 respectively; The source S of described power switch tube S b2 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 the grid G of described power switch tube S b1, the grid G of power switch tube S b2, power switch tube S b3, the equal sky of grid G of power switch tube S b4 connect; On described power switch tube S b1, power switch tube S b2, power switch tube S b3 and power switch tube S b4 also respectively and connect a diode; Described the 3rd brachium pontis comprises power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4; The drain D of described power switch tube S c1 connects high level; The source S of described power switch tube S c1 is connected with the drain D of power switch tube S c2, the drain D of power switch tube S c4 respectively; The source S of described power switch tube S c2 is connected with the source S of power switch tube S c3; 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 the grid G of described power switch tube S c1, the grid G of power switch tube S c2, power switch tube S c3, the equal sky of grid G of power switch tube S c4 connect; On described power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4 also respectively and connect a diode; Described the 4th brachium pontis comprises power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4; The drain D of described power switch tube S d1 connects high level; The source S of described power switch tube S d1 is connected with the drain D of power switch tube S d2, the drain D of power switch tube S d4 respectively; The source S of described power switch tube S d2 is connected with the source S of power switch tube S d3; The drain D of described power switch tube S d3 connects bus neutral point O; The source S of described power switch tube S d4 connects low level; The grid G of the grid G of described power switch tube S d1, the grid G of power switch tube S d2, power switch tube S d3, the equal sky of grid G of power switch tube S d4 connect; On described power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4 also respectively and connect a diode;
Described filter circuit comprises filter inductance L3 and filter capacitor C3; Described filter inductance L3 is made up of four inductance, and is connected with four brachium pontis in direct-current-alternating-current converter (DC-AC converter) respectively; Described filter capacitor C3 is made up of four lotus-seed pastes; Described four electric capacity one end parallel connections; The other end is electrically connected 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, suppress current in middle wire switching harmonics, reduce total harmonic distortion (THD) value of three-phase output voltage.
The driving signal complementation of the driving signal of described power switch tube S a1 and power switch tube S a3, and 2us Dead Time is set simultaneously; The driving signal complementation of the driving signal of power switch tube S a2 and power switch tube S a4, and 2us Dead Time is set simultaneously; The driving signal complementation of the driving signal of power switch tube S b1 and power switch tube S b3, and 2us Dead Time is set simultaneously, the driving signal complementation of the driving signal of power switch tube S b2 and power switch tube S b4, and 2us Dead Time is set simultaneously; The driving signal complementation of the driving signal of power switch tube S c1 and power switch tube S c3, and 2us Dead Time is set simultaneously, the driving signal complementation of the driving signal of power switch tube S c2 and power switch tube S c4, and 2us Dead Time is set simultaneously; The driving signal complementation of the driving signal of power switch tube S n1 and power switch tube S n3, and 2us Dead Time is set simultaneously, the driving signal complementation of the driving signal of power switch tube S n2 and power switch tube S n4, and 2us Dead Time is set simultaneously.
Being mainly used in of described Dead Time prevents that switching tube is straight-through, and the time turning on and off according to switching tube that arranges of Dead Time is determined.
Described controller is MPPT controller; Described MPPT controller is pi controller.
Described the 4th brachium pontis is public brachium pontis, is used to unsymmetrical current or zero-sequence current that path is provided.
Described the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, the 4th brachium pontis are equipped with three level brachium pontis mid points, are designated as respectively A, B, C, N; Described A, B, C, 4 outputs as described direct-current-alternating-current converter (DC-AC converter) of N.
Compared with diode clamp type three level grid-connected systems, this bright beneficial effect is: each brachium pontis of the present utility model is than few two diodes of the brachium pontis of prior art; And four brachium pontis pick out four terminals; Can meet to the utmost 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; The fail safe that simultaneously can also effectively improve system, widens the range of application of photovoltaic DC-to-AC converter.
Accompanying drawing explanation
Fig. 1 is structured flowchart of the present utility model;
Fig. 2 is T-shaped three-phase four-wire system grid-connected photovoltaic system circuit structure diagram of the present utility model
Fig. 3 is the control principle drawing of DC-DC converter;
Fig. 4 is the three dimensional vector diagram of line voltage orientation;
The control principle drawing of Fig. 5 direct-current-alternating-current converter;
Embodiment
The embodiment providing below in conjunction with accompanying drawing is further described the utility model:
As shown in Figure 1, the T-shaped three level three-phase four-arm grid-connected photovoltaic systems of the utility model, comprise DC-DC converter (DC-DC converter), direct-current-alternating-current converter (DC-AC converter), photovoltaic array, filter circuit and controller; Described photovoltaic array, controller are electrically connected with DC-DC converter (DC-DC converter) respectively; The output of described DC-DC converter (DC-DC converter) is electrically connected with the input of direct-current-alternating-current converter (DC-AC converter); The output of described direct-current-alternating-current converter (DC-AC converter) is electrically connected with the input of filter circuit circuit; The output of described filter circuit is provided with four relays, is respectively S1, S2, S3, S4; Described filter circuit is electrically connected with the input of four relays respectively; The output of described relay is provided with electrical network e
a, e
b, e
c; Described relay S1 and electrical network e
ainput electrical connection; Described relay S2 and electrical network e
binput electrical connection; Described relay S3 and electrical network e
cinput electrical connection; Described relay S4 respectively with electrical network e
a, e
b, e
coutput electrical connection;
As shown in Figure 2, described DC-DC converter comprises power switch pipe sd1, power switch pipe sd2, inductance L 1, inductance L 2, power diode D1, power diode D2, capacitor C 1 and capacitor C 2; Described capacitor C 1 and capacitor C 2 form DC bus filter-capacitor circuit, and on DC bus, form a neutral point O; The negative pole of described capacitor C 1 is electrically connected with the positive pole of capacitor C 2; The positive pole of described capacitor C 1 connects high level; The negative pole of described capacitor C 2 connects low level; The drain D of described power switch pipe sd1 is electrically connected with the positive pole of power diode D1, one end of inductance L 1 respectively; The negative pole of described power diode D1 connects high level; The other end of described inductance L 1 is connected with photovoltaic array; The source S of described power switch pipe sd1 is connected with the drain D of power switch pipe sd2; The source S of described power switch pipe sd2 is connected with one end of inductance L 2, the negative electricity of switching diode D2 respectively; The positive pole of described switching diode D2 connects low level; The other end of described inductance L 2 is connected with photovoltaic array; The grid G of described power switch pipe sd1, the equal sky of grid G of power switch pipe sd2 connect; On described power switch pipe sd1 and power switch pipe sd2 also respectively and connect a diode; Described power switch pipe sd1 and power switch pipe sd2 composition Boost booster circuit;
As shown in Figure 2, described direct-current-alternating-current converter (DC-AC converter) connects the neutral point O with DC bus, is made up of four brachium pontis, and described brachium pontis is respectively the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, the 4th brachium pontis; Described the first brachium pontis comprises power switch tube S a1, 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 is connected with the drain D of power switch tube S a2, the drain D of power switch tube S a4 respectively; 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; The grid G of the grid G of described power switch tube S a1, the grid G of power switch tube S a2, power switch tube S a3, the equal sky of grid G of power switch tube S a4 connect; On described power switch tube S a1, power switch tube S a2, power switch tube S a3, power switch tube S a4 also respectively and connect a diode; Described the second brachium pontis comprises power switch tube S b1, power switch tube S b2, power switch tube S b3 and power switch tube S b4; The drain D of described power switch tube S b1 connects high level; The source S of described power switch tube S b1 is connected with the drain D of power switch tube S b2, the drain D of power switch tube S b4 respectively; The source S of described power switch tube S b2 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 the grid G of described power switch tube S b1, the grid G of power switch tube S b2, power switch tube S b3, the equal sky of grid G of power switch tube S b4 connect; On described power switch tube S b1, power switch tube S b2, power switch tube S b3 and power switch tube S b4 also respectively and connect a diode; Described the 3rd brachium pontis comprises power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4; The drain D of described power switch tube S c1 connects high level; The source S of described power switch tube S c1 is connected with the drain D of power switch tube S c2, the drain D of power switch tube S c4 respectively; The source S of described power switch tube S c2 is connected with the source S of power switch tube S c3; 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 the grid G of described power switch tube S c1, the grid G of power switch tube S c2, power switch tube S c3, the equal sky of grid G of power switch tube S c4 connect; On described power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4 also respectively and connect a diode; Described the 4th brachium pontis comprises power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4; The drain D of described power switch tube S d1 connects high level; The source S of described power switch tube S d1 is connected with the drain D of power switch tube S d2, the drain D of power switch tube S d4 respectively; The source S of described power switch tube S d2 is connected with the source S of power switch tube S d3; The drain D of described power switch tube S d3 connects bus neutral point O; The source S of described power switch tube S d4 connects low level; The grid G of the grid G of described power switch tube S d1, the grid G of power switch tube S d2, power switch tube S d3, the equal sky of grid G of power switch tube S d4 connect; On described power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4 also respectively and connect a diode;
As shown in Figure 2, described filter circuit comprises filter inductance L3 and filter capacitor C3; Described filter inductance L3 is made up of four inductance, and is connected with four brachium pontis in direct-current-alternating-current converter (DC-AC converter) respectively; Described filter capacitor C3 is made up of four lotus-seed pastes; Described four electric capacity one end parallel connections; The other end is electrically connected 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, suppress current in middle wire switching harmonics, reduce total harmonic distortion (THD) value of three-phase output voltage.
Described the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, the 4th brachium pontis are equipped with three level brachium pontis mid points, are designated as respectively A, B, C, N; Described A, B, C, 4 outputs as described direct-current-alternating-current converter (DC-AC converter) of N.
The utility model also relates to the control method of T-shaped three level three-phase four-arm photovoltaic grid-connected inversion electricity generation systems, this control method is mainly take digital signal processor TMS320F2808 and CPLD as core, utilizes 12,16 tunnel of Pian Nei AD module to sample to signal acquisition circuit signal; There is control algolithm to write by C language in the program storage of 32-bit number process chip TMS320F2808;
The effect of described digital signal processor CPLD is expansion PWM mouth;
Concrete steps are as follows:
The first step: utilize C language compilation programming control program;
Second step: control program is write in the program storage of 32-bit number process chip TMS320F2808;
The 3rd step: start controller, and control the output voltage V of DC-DC converter collection photovoltaic array
pVwith output current I
pV;
The 4th step: carry out the conversion of DC-DC according to the switching control method of DC-DC converter, obtain the driving signal at power switch pipe sd1, sd2 two ends;
The 5th step: by the driving signal input direct-current-AC converter at power switch pipe sd1, sd2 two ends;
The 6th step: carry out the conversion of DC-AC according to the switching control method of direct-current-alternating-current converter, obtain the driving signal of T-shaped three-phase tri-level four brachium pontis.
As shown in Figure 3, described DC-DC converter is for realizing the conversion of DC-DC; The utility model also relates to the switching control method of DC-DC converter: the conversion and control of described DC-DC is mainly the output voltage V that gathers photovoltaic array by described DC-DC converter
pVwith output current I
pV; And obtain by maximal power tracing control algolithm after the reference voltage of photovoltaic array; Again through the duty ratio of two closed-loop control Boost booster circuits of overvoltage, electric current;
Concrete steps are as follows:
The first step: described DC-DC converter gathers the output voltage V of photovoltaic array
pVwith output current I
pV; Through maximal power tracing control algolithm, in the utility model, adopt disturbance observation to obtain the reference voltage V of photovoltaic array
ref;
Second step: the reference voltage V of described photovoltaic array
refwith photovoltaic array output voltage V
pVthrough calculating, draw voltage difference, and form voltage difference signal; This voltage difference signal is sent into proportional integral (Proportion Integrate, PI) controller; Through the reference current I that automatically calculates photovoltaic array of pi controller
ref;
The 3rd step: the reference current I of described photovoltaic array
refwith photovoltaic array output current I
pVthrough calculating, draw electric current difference, and form current difference signal; And this current difference signal is sent into pi controller; Effect through pi controller produces control signal;
The 4th step: the control signal producing, after PWM modulation, produce pwm pulse ripple, pwm pulse ripple is flowed to power switch pipe sd1 and the power switch pipe sd2 in DC-DC converter, carry out work for driving power switching tube sd1 and power switch pipe sd2, complete 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.
As Fig. 4, as shown in Figure 5, described direct-current-alternating-current converter (DC-AC converter), for realizing the conversion of DC-AC, converts 220V, 50Hz sine wave to by direct current; The utility model also relates to the switching control method of direct-current-alternating-current converter: the conversion and control of described DC-AC is mainly the vector control by line voltage, be mainly to adopt voltage and current double-loop control strategy, the effect of line voltage outer shroud is stable DC busbar voltage; The Main Function of interior ring is, accurate tracking quick to given electric current;
Concrete steps are as follows:
The first step: set up voltage-to-current ring, described voltage-to-current is equipped with outer shroud and interior ring; Described outer shroud is DC bus-bar voltage ring; Described interior ring is d shaft current, q shaft current; Getting bus neutral point O is zero point, sets up alpha-beta coordinate system; And in alpha-beta coordinate system, set up dq0 rotating coordinate system; Get e
d, e
q, e
0be respectively d shaft voltage, q shaft voltage, zero shaft voltage of three phase network voltage under dq0 rotating coordinate system; Get i
d, i
q, i
0be respectively d shaft current, q shaft current, the zero-axis current of combining inverter output current under dq0 rotating coordinate system;
Second step: give the voltage and current equation under coordinate system while fixing on three phase static, equation is:
In (1) formula, VAn, VBn, VCn are respectively the voltage between voltage, the 3rd brachium pontis and the 4th brachium pontis between voltage, the second brachium pontis and the 4th brachium pontis between the first brachium pontis and the 4th brachium pontis in direct-current-alternating-current converter; e
a, e
b, e
cbe respectively the phase voltage of three phase network; i
a, i
b, i
c, i
nbe respectively and in direct-current-alternating-current converter, export A phase current, B phase current, C phase current and current in middle wire, the electric current that output terminals A, B, C, N are ordered;
The 3rd step: by the voltage in dq0 rotating coordinate system, current parameters substitution formula (1), can obtain:
In formula (3), V
d, V
q, V
0be respectively d shaft voltage, q shaft voltage, zero shaft voltage of combining inverter output voltage in dq0 rotating coordinate system; e
d, e
q, e
0be respectively d shaft voltage, q shaft voltage, zero shaft voltage of three phase network voltage under dq0 rotating coordinate system; i
d, i
q, i
0be respectively d shaft current, q shaft current, the zero-axis current of combining inverter output current under dq0 rotating coordinate system; ω is the angular frequency of three phase network voltage
The 4th step: the space angle signal θ that obtains line voltage by software phlase locking closed loop (phase locked loop, PLL); Three phase network current i
a, i
b, i
cobtain d shaft current, q shaft current through coordinate system transformation;
The 5th step: given d-c bus voltage value, and calculate this voltage signal and DC bus actual voltage value V
dcdifference, produce voltage difference signal; This voltage difference signal is sent into proportional integral (Proportion Integrate, PI) controller, after pi controller calculates automatically, obtain the given signal of interior ring d shaft current;
Concrete, given d-c bus voltage value is=650V;
The 6th step: difference between the given signal of calculating d shaft current and actual d shaft current, and generation current value signal; Difference between the given signal of calculating q shaft current and actual q shaft current, and generation current value signal; These two difference signals are sent into proportional integral (Proportion Integrate, PI) controller, after pi controller calculates automatically, obtain the reference voltage of d axle reference voltage, q shaft voltage;
The 7th step: in dq0 rotating coordinate system, the reference voltage of d axle reference voltage, q shaft voltage is carried out to transformation conversion, obtain reference voltage and; By and the reference voltage of zero axle obtain the driving signal of T-shaped three-phase tri-level four brachium pontis through three-dimensional space vectors modulation (3DSVPWM).
Claims (5)
1. T-shaped three level three-phase four-arm grid-connected photovoltaic systems, comprise DC-DC converter (DC-DC converter), direct-current-alternating-current converter (DC-AC converter), photovoltaic array, filter circuit and controller; It is characterized in that: described photovoltaic array, controller are electrically connected with DC-DC converter (DC-DC converter) respectively; The output of described DC-DC converter (DC-DC converter) is electrically connected with the input of direct-current-alternating-current converter (DC-AC converter); The output of described direct-current-alternating-current converter (DC-AC converter) is electrically connected with the input of filter circuit circuit; The output of described filter circuit is provided with four relays, is respectively S1, S2, S3, S4; Described filter circuit is electrically connected with the input of four relays respectively; The output of described relay is provided with electrical network e
a, e
b, e
c; Described relay S1 and electrical network e
ainput electrical connection; Described relay S2 and electrical network e
binput electrical connection; Described relay S3 and electrical network e
cinput electrical connection; Described relay S4 respectively with electrical network e
a, e
b, e
coutput electrical connection.
2. T-shaped three level three-phase four-arm grid-connected photovoltaic systems according to claim 1, is characterized in that: described DC-DC converter comprises power switch pipe sd1, power switch pipe sd2, inductance L 1, inductance L 2, power diode D1, power diode D2, capacitor C 1 and capacitor C 2; Described capacitor C 1 and capacitor C 2 form DC bus filter-capacitor circuit, and on DC bus, form a neutral point O; The negative pole of described capacitor C 1 is electrically connected with the positive pole of capacitor C 2; The positive pole of described capacitor C 1 connects high level; The negative pole of described capacitor C 2 connects low level; The drain D of described power switch pipe sd1 is electrically connected with the positive pole of power diode D1, one end of inductance L 1 respectively; The negative pole of described power diode D1 connects high level; The other end of described inductance L 1 is connected with photovoltaic array; The source S of described power switch pipe sd1 is connected with the drain D of power switch pipe sd2; The source S of described power switch pipe sd2 is connected with one end of inductance L 2, the negative electricity of switching diode D2 respectively; The positive pole of described switching diode D2 connects low level; The other end of described inductance L 2 is connected with photovoltaic array; The grid G of described power switch pipe sd1, the equal sky of grid G of power switch pipe sd2 connect; On described power switch pipe sd1 and power switch pipe sd2 also respectively and connect a diode; Described power switch pipe sd1 and power switch pipe sd2 composition Boost booster circuit.
3. T-shaped three level three-phase four-arm grid-connected photovoltaic systems according to claim 1, it is characterized in that: described direct-current-alternating-current converter (DC-AC converter) connects the neutral point O with DC bus, be made up of four brachium pontis, described brachium pontis is respectively the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, the 4th brachium pontis; Described the first brachium pontis comprises power switch tube S a1, 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 is connected with the drain D of power switch tube S a2, the drain D of power switch tube S a4 respectively; 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; The grid G of the grid G of described power switch tube S a1, the grid G of power switch tube S a2, power switch tube S a3, the equal sky of grid G of power switch tube S a4 connect; On described power switch tube S a1, power switch tube S a2, power switch tube S a3, power switch tube S a4 also respectively and connect a diode; Described the second brachium pontis comprises power switch tube S b1, power switch tube S b2, power switch tube S b3 and power switch tube S b4; The drain D of described power switch tube S b1 connects high level; The source S of described power switch tube S b1 is connected with the drain D of power switch tube S b2, the drain D of power switch tube S b4 respectively; The source S of described power switch tube S b2 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 the grid G of described power switch tube S b1, the grid G of power switch tube S b2, power switch tube S b3, the equal sky of grid G of power switch tube S b4 connect; On described power switch tube S b1, power switch tube S b2, power switch tube S b3 and power switch tube S b4 also respectively and connect a diode; Described the 3rd brachium pontis comprises power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4; The drain D of described power switch tube S c1 connects high level; The source S of described power switch tube S c1 is connected with the drain D of power switch tube S c2, the drain D of power switch tube S c4 respectively; The source S of described power switch tube S c2 is connected with the source S of power switch tube S c3; 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 the grid G of described power switch tube S c1, the grid G of power switch tube S c2, power switch tube S c3, the equal sky of grid G of power switch tube S c4 connect; On described power switch tube S c1, power switch tube S c2, power switch tube S c3 and power switch tube S c4 also respectively and connect a diode; Described the 4th brachium pontis comprises power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4; The drain D of described power switch tube S d1 connects high level; The source S of described power switch tube S d1 is connected with the drain D of power switch tube S d2, the drain D of power switch tube S d4 respectively; The source S of described power switch tube S d2 is connected with the source S of power switch tube S d3; The drain D of described power switch tube S d3 connects bus neutral point O; The source S of described power switch tube S d4 connects low level; The grid G of the grid G of described power switch tube S d1, the grid G of power switch tube S d2, power switch tube S d3, the equal sky of grid G of power switch tube S d4 connect; On described power switch tube S d1, power switch tube S d2, power switch tube S d3 and power switch tube S d4 also respectively and connect a diode.
4. T-shaped three level three-phase four-arm grid-connected photovoltaic systems according to claim 3, is characterized in that: described the 4th brachium pontis is public brachium pontis, is used to unsymmetrical current or zero-sequence current that path is provided; Described the first brachium pontis, the second brachium pontis, the 3rd brachium pontis, the 4th brachium pontis are equipped with three level brachium pontis mid points, are designated as respectively A, B, C, N; Described A, B, C, 4 outputs as described direct-current-alternating-current converter (DC-AC converter) of N.
5. T-shaped three level three-phase four-arm grid-connected photovoltaic systems according to claim 1, is characterized in that: described filter circuit comprises filter inductance L3 and filter capacitor C3; Described filter inductance L3 is made up of four inductance, and is connected with four brachium pontis in direct-current-alternating-current converter (DC-AC converter) respectively; Described filter capacitor C3 is made up of four electric capacity; Described four electric capacity one end parallel connections; The other end is electrically connected 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, suppress current in middle wire switching harmonics, reduce total harmonic distortion (THD) value of three-phase output voltage.
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| CN201420000373.4U CN203674732U (en) | 2014-01-02 | 2014-01-02 | T-type three-level three-phase four-leg photovoltaic gird-connected power generation system |
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| CN201420000373.4U CN203674732U (en) | 2014-01-02 | 2014-01-02 | T-type three-level three-phase four-leg photovoltaic gird-connected power generation system |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104467005A (en) * | 2014-01-02 | 2015-03-25 | 艾伏新能源科技(上海)股份有限公司 | T-type three-level three-phase four-bridge-arm grid-connected photovoltaic power generation system and control method thereof |
| CN106787860A (en) * | 2016-12-30 | 2017-05-31 | 杭州禾迈电力电子技术有限公司 | A kind of single-stage isolated type Three-phase PFC |
| US10103647B2 (en) | 2016-08-17 | 2018-10-16 | Industrial Technology Research Institute | Sensorless measurement method and device for filter capacitor current by using a state observer |
| CN115811243A (en) * | 2022-12-02 | 2023-03-17 | 江苏科曜能源科技有限公司 | T-shaped three-phase three-level four-bridge-arm quasi-Z-source inverter device |
| EP3455932B1 (en) * | 2016-05-09 | 2023-07-19 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device and method for generating an ac voltage |
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2014
- 2014-01-02 CN CN201420000373.4U patent/CN203674732U/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104467005A (en) * | 2014-01-02 | 2015-03-25 | 艾伏新能源科技(上海)股份有限公司 | T-type three-level three-phase four-bridge-arm grid-connected photovoltaic power generation system and control method thereof |
| EP3455932B1 (en) * | 2016-05-09 | 2023-07-19 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device and method for generating an ac voltage |
| US10103647B2 (en) | 2016-08-17 | 2018-10-16 | Industrial Technology Research Institute | Sensorless measurement method and device for filter capacitor current by using a state observer |
| CN106787860A (en) * | 2016-12-30 | 2017-05-31 | 杭州禾迈电力电子技术有限公司 | A kind of single-stage isolated type Three-phase PFC |
| CN106787860B (en) * | 2016-12-30 | 2023-06-16 | 杭州禾迈电力电子股份有限公司 | Single-stage isolated three-phase PFC converter |
| CN115811243A (en) * | 2022-12-02 | 2023-03-17 | 江苏科曜能源科技有限公司 | T-shaped three-phase three-level four-bridge-arm quasi-Z-source inverter device |
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