CN206302163U - A kind of grid-connected photovoltaic system based on the quasi- Z-source inverter of cascade - Google Patents
A kind of grid-connected photovoltaic system based on the quasi- Z-source inverter of cascade Download PDFInfo
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- CN206302163U CN206302163U CN201621292017.XU CN201621292017U CN206302163U CN 206302163 U CN206302163 U CN 206302163U CN 201621292017 U CN201621292017 U CN 201621292017U CN 206302163 U CN206302163 U CN 206302163U
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- 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
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Abstract
The utility model provides a kind of based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, and grid-connected composition is cascaded by three single-stage photovoltaic generating modules；Each single-stage photovoltaic generating module includes photovoltaic cells and quasi- Z-source inverter unit, and quasi- Z-source inverter unit includes impedance network boosting unit and ac converter unit；The quasi- Z-source inverter unit of each single-stage photovoltaic generating module is cascaded after inductance L is connected with power network and forms three-phase photovoltaic grid-connected electricity generation system；Pass through inductance L between the quasi- Z-source inverter unit of each twodConnection；Impedance network boosting unit is defined Z source impedance network boosting units；N-th impedance network boosting unit of single-stage photovoltaic generating module is by inductance L2n‑1, electric capacity C2nWith inductance L2nConnected by peripheral circuit and constituted.The grid-connected photovoltaic system can reduce the voltage class requirement to photovoltaic array, the power grade of lifting system, and reduce the switch stress of switching device, while realizing that many level outputs improve the output quality of power supply.
Description
Technical field
The utility model is related to technical field of photovoltaic power generation, more specifically to one kind based on the quasi- Z-source inverter of cascade
Grid-connected photovoltaic system.
Background technology
In whole grid-connected photovoltaic system, inverter is core component and key technology place, and it occupies system
The 10%-15% of cost, plays the role of important to the stability and generating efficiency of system.The research direction of combining inverter is big
Cause can be divided into concentration combining inverter and the class of miniature grid-connected inverter two：
The first kind is centralized combining inverter, and its simple structure, unit cost is cheap, only needs a concentration parallel network reverse
Device can make centralized grid-connected system reach MW class, but bulky, it is impossible to overcome photovoltaic module installation and battery behavior poor
The different nonuniformity for causing, reduces system whole efficiency, is only suitable for large-scale photovoltaic plant.
Equations of The Second Kind is Miniature inverter, and it is the device that generates electricity by way of merging two or more grid systems based on single solar cell module, can be to monolithic
The maximum power point of component is tracked, and greatly improves the generated energy of photovoltaic system.However, Miniature inverter also has its corresponding
Limitation：Single-stage output voltage range is limited, it is necessary to additional one-level DC/DC current transformers can just obtain input voltage wider
Scope；Identical bridge arm can not be simultaneously turned on, fragile active switching devices；Anti-electromagnetic interference capability difference etc..
For the deficiency of conventional inverter, Peng Fang full professors propose Z source converters.Z source converters are asked in power conversion
There are a kind of new approaches and new theory for being different from conventional inverter in topic, traditional inversion can be made up while inversion is realized
The deficiency of device.Pass-through state is added in the working condition of Z-source inverter, two bridge up and down for forbidding occurring in conventional inverter
The pass-through state that arm is simultaneously turned on is used, and on the one hand due to the addition of pass-through state, realizes the boosting work(of output voltage
Can, instead of the transformer or DC/DC voltage-boosting stages in conventional inverter two-stage structure；Another side, in eliminating conventional inverter
In order to avoid the wave distortion for the ac output voltage that switching dead that is straight-through and setting is brought occur, inverter is improve active
The security of device, enhances its antijamming capability.In addition, with the progress of Power Electronic Technique, multi-electrical level inverter topology
There is voltage and power grade is high, the low advantage of grid-connected current harmonic content, be widely used in engineering, main flow structural topology
There are three kinds：Diode-clamped, striding capacitance type and cascade connection type.Wherein, cascaded multilevel inverter topology is relative to above two
Had the advantage that for many level topologys of kind：Harmonic wave of output voltage aberration rate is small；In the absence of capacitance voltage imbalance problem；Can lead to
Cross and high pressure, low-frequency operation are realized using the device of a large amount of low-voltage-grades, it is not necessary to Series power pipe；Do not need clamp capacitor and
Clamp diode；Realize that the number of power switch tube device needed during same level number is minimum, it is easy to modularized design.
In sum, it will study from now on that high efficiency, low cost, low-power consumption, the grid-connected photovoltaic system of low harmony wave are
Trend, by analyzing the operation principle by quasi- Z-source inverter and cascaded inverter, it is possible to find if by quasi- Z-source inverter and
The advantage of both cascaded inverters is combined, and can reach desired effect.Therefore, how to design one kind can lifting system
Power grade, and reduce the switch stress of switching device, while realizing that many level outputs can improve the base of output voltage quality
Studied from now on for photovoltaic power generation technology in the grid-connected photovoltaic system for cascading quasi- Z-source inverter and had very important significance.
Utility model content
The purpose of this utility model is to overcome shortcoming of the prior art with deficiency, there is provided one kind is based on the quasi- Z sources of cascade
The grid-connected photovoltaic system of inverter, the grid-connected photovoltaic system can reduce the voltage class requirement to photovoltaic array, carry
The power grade of the system of liter, and reduce the switch stress of switching device, while realizing that many level outputs improve the output quality of power supply.
In order to achieve the above object, the utility model is achieved by following technical proposals：One kind is based on the quasi- Z sources of cascade
The grid-connected photovoltaic system of inverter, it is characterised in that：Grid-connected composition is cascaded by three single-stage photovoltaic generating modules；Each institute
Stating single-stage photovoltaic generating module includes photovoltaic cells and quasi- Z-source inverter unit, wherein, quasi- Z-source inverter unit includes
Impedance network boosting unit and ac converter unit；The quasi- Z-source inverter unit of each single-stage photovoltaic generating module passes through
Cascade forms three-phase photovoltaic grid-connected electricity generation system after inductance L is connected with power network；By electricity between the quasi- Z-source inverter unit of each two
Sense LdConnection；The impedance network boosting unit is defined Z source impedance network boosting units；N-th single-stage photovoltaic generating module
Impedance network boosting unit is by inductance L2n-1, electric capacity C2nWith inductance L2nConnected by peripheral circuit and constituted, wherein, n=1,2 and 3.
In such scheme, the utility model is based on the grid-connected photovoltaic system of the quasi- Z-source inverter of cascade using cascade
The benefit of structure is：A) class requirement of photovoltaic battery panel voltage is reduced；B) power grade of lifting system；C) many level are defeated
Go out to improve the output quality of power supply；D) switch stress of switching device is reduced.The utility model is based on the quasi- Z-source inverter photovoltaic of cascade
The characteristics of what grid-connected system structure possessed first is photovoltaic system, by factors such as illumination size, temperature height, shade maskings
Influence so that DC side voltage value fluctuation, then possess be quasi- Z-source inverter the characteristics of, it is necessary to the straight of Z net
Logical dutycycle is controlled, and the purpose of photovoltaic generating system single-stage transformation is realized so as to reach, and is finally cascade connection multi-level inversion
The characteristics of device, n cascade module its output voltage waveforms just have 2n+1 level, and harmonic content greatly reduces.
Each single-stage photovoltaic generating module also includes electric capacity of voltage regulation Cin, the electric capacity of voltage regulation CinWith photovoltaic cells simultaneously
Connection.
The ac converter unit of each single-stage photovoltaic generating module is voltage source inverter VSI.
The utility model also includes dsp controller and Hall voltage sensor；The dsp controller is passed by Hall voltage
Sensor is connected with power network.Hall voltage sensor of the present utility model detects that line voltage is carried out in being input to dsp controller
PLL locks phase.
Described each single-stage photovoltaic generating module also includes that DC capacitor voltage sample circuit and quasi- Z-source inverter are exported
Voltage x current sample circuit；Quasi- Z-source inverter unit in described each single-stage photovoltaic generating module is by DC bus capacitor electricity
Pressure sample circuit is connected with dsp controller；The output end of the quasi- Z-source inverter unit in described each single-stage photovoltaic generating module
It is connected with dsp controller by output voltage current sampling circuit.Wherein, DC capacitor voltage sample circuit and quasi- Z sources are inverse
It is circuit of the prior art to become device output voltage current sampling circuit, two sampling circuit samples to numerical value be input to DSP
In controller, can be directed at Z-source inverter unit carries out the control of dutycycle and modulation ratio.
Described each single-stage photovoltaic generating module also includes PWM drive circuit；The dsp controller drives electricity by PWM
Road is connected with the quasi- Z-source inverter unit in each single-stage photovoltaic generating module.The control signal of dsp controller is exported to PWM
Drive circuit, can drive the switching tube of quasi- Z-source inverter unit to work by PWM drive circuit.
Described each single-stage photovoltaic generating module also includes Hall current sensor；In each single-stage photovoltaic generating module
Power network is connected by Hall current sensor with dsp controller.The Hall current sensor of each single-stage photovoltaic generating module is adopted
Sample correspondence phase current carries out current control in being input to dsp controller.
Described each single-stage photovoltaic generating module also includes photovoltaic cell voltage and current detection circuit；Described each single-stage light
Photovoltaic cells in volt electricity generation module are connected by voltage and current detection circuit with dsp controller.Wherein, photovoltaic cell electricity
Piezoelectricity current detection circuit is circuit of the prior art, the photovoltaic cell measure voltage ＆ current in each single-stage photovoltaic generating module
Be input to the output voltage current value of photovoltaic cells in dsp controller by circuit, and MPPT controls are carried out to photovoltaic cell.
Compared with prior art, the utility model has the following advantages that and beneficial effect：The utility model is based on the quasi- Z of cascade
The grid-connected photovoltaic system of source inventer, the grid-connected photovoltaic system can reduce the voltage class requirement to photovoltaic array,
The power grade of lifting system, and reduce the switch stress of switching device, while realizing that many level outputs improve output electric energy matter
Amount.
Brief description of the drawings
Fig. 1 is the utility model in the schematic diagram of the grid-connected photovoltaic system for cascading quasi- Z-source inverter；
Fig. 2 is system architecture schematic diagram；
Wherein, 1 be photovoltaic cells, 2 be defined Z-source inverter unit, 3 be power network, 4 be PWM drive circuit, 5 is straight
Stream lateral capacitance voltage sampling circuit, 6 be defined Z-source inverter output voltage current sampling circuit, 7 be Hall voltage sensor, 8 be
Hall current sensor, 9 be photovoltaic cell output voltage current sampling circuit, 10 be dsp controller.
Specific embodiment
The utility model is described in further detail with specific embodiment below in conjunction with the accompanying drawings.
Embodiment
As depicted in figs. 1 and 2, the grid-connected photovoltaic system that the utility model is based on the quasi- Z-source inverter of cascade is by three
Individual single-stage photovoltaic generating module cascades grid-connected composition, and each single-stage photovoltaic generating module includes photovoltaic cells 1 and quasi- Z sources
Inverter unit 2, wherein, quasi- Z-source inverter unit includes impedance network boosting unit and ac converter unit, each single-stage again
The quasi- Z-source inverter unit of photovoltaic generating module is cascaded after inductance L is connected with power network 3 and forms the three-phase photovoltaic grid-connected system that generates electricity
System.Pass through inductance L between the quasi- Z-source inverter unit of each twodConnection.
The Z source impedance network boosting units and impedance network boosting unit is defined；N-th impedance of single-stage photovoltaic generating module
Network boosting unit is by inductance L2n-1, electric capacity C2nWith inductance L2nConnected by peripheral circuit and constituted, wherein, n=1,2 and 3.
Each single-stage photovoltaic generating module of the present utility model also includes electric capacity of voltage regulation Cin, electric capacity of voltage regulation CinWith photovoltaic electric
Pool unit 1 is in parallel.
The ac converter unit of each single-stage photovoltaic generating module of the present utility model is voltage source inverter VSI.
The grid-connected photovoltaic system that the utility model is based on the quasi- Z-source inverter of cascade is using the benefit of cascade structure：
A) class requirement of photovoltaic battery panel voltage is reduced；B) power grade of lifting system；C) many level outputs improve output electricity
Can quality；D) switch stress of switching device is reduced.The utility model is based on the quasi- Z-source inverter grid-connected photovoltaic system of cascade
The characteristics of what structure possessed first is photovoltaic system, is influenceed by factors such as illumination size, temperature height, shade maskings so that
DC side voltage value fluctuation, then possess be quasi- Z-source inverter the characteristics of, it is necessary to enter to the straight-through dutycycle of Z net
Row control, so as to realize the purpose of photovoltaic generating system single-stage transformation, the characteristics of be finally cascaded multilevel inverter, n level
Gang mould block its output voltage waveforms just have 2n+1 level, and harmonic content greatly reduces.
The utility model also includes dsp controller 10 and Hall voltage sensor 7, and the dsp controller 10 is by Hall electricity
Pressure sensor 7 is connected with power network 3.Hall voltage sensor of the present utility model 7 detects the control source of power network 3 to DSP controls
PLL lock phases are carried out in device 10.
Each single-stage photovoltaic module also includes DC capacitor voltage sample circuit 5 and quasi- Z-source inverter output voltage electricity
Stream sample circuit 6, wherein, the quasi- Z-source inverter unit in each single-stage photovoltaic generating module is adopted by DC capacitor voltage
Sample circuit 5 is connected with dsp controller 10, and the output end of the quasi- Z-source inverter unit in each single-stage photovoltaic generating module passes through
Quasi- Z-source inverter output voltage current sampling circuit 6 is connected with dsp controller 10.And the He of DC capacitor voltage sample circuit 5
Quasi- Z-source inverter output voltage current sampling circuit 6 is circuit of the prior art, and the numerical value that two sampling circuit samples are arrived is defeated
Enter in dsp controller 10, can be directed at Z-source inverter unit carries out the control of dutycycle and modulation ratio.
Each single-stage photovoltaic generating module also includes PWM drive circuit 4, wherein, dsp controller 10 drives electricity by PWM
Road 4 is connected with the quasi- Z-source inverter unit 2 in each single-stage photovoltaic generating module.The control signal of dsp controller 10 export to
PWM drive circuit 4, can drive the switching tube of quasi- Z-source inverter unit 2 to work by PWM drive circuit 4.
Each single-stage photovoltaic generating module also includes Hall current sensor 8；Electricity in each single-stage photovoltaic generating module
Net 3 is connected by Hall current sensor 8 with dsp controller 10.The Hall current sensor 8 of each single-stage photovoltaic generating module
Sampling correspondence phase current carries out current control in being input to dsp controller 10.
Each single-stage photovoltaic generating module also includes photovoltaic cell voltage and current detection circuit 9, each single-stage photovoltaic generation
Photovoltaic cells 1 in module are connected by photovoltaic cell voltage and current detection circuit 9 with dsp controller 10.Wherein, photovoltaic
Cell voltage current detection circuit 9 is circuit of the prior art, the photovoltaic cell voltage in each single-stage photovoltaic generating module
Be input to the output voltage current value of photovoltaic cell in dsp controller 10 by current detection circuit 9, and MPPT is carried out to photovoltaic cell
Control.
Above-described embodiment is the utility model preferably implementation method, but implementation method of the present utility model is not by above-mentioned
The limitation of embodiment, it is other it is any without departing from the change made under Spirit Essence of the present utility model and principle, modify, replace
Generation, combination, simplification, should be equivalent substitute mode, be included within protection domain of the present utility model.
Claims (8)
1. a kind of based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：By three single-stage photovoltaic generations
The grid-connected composition of module-cascade；Each described single-stage photovoltaic generating module includes photovoltaic cells and quasi- Z-source inverter unit, its
In, quasi- Z-source inverter unit includes impedance network boosting unit and ac converter unit；Each described single-stage photovoltaic generating module
Quasi- Z-source inverter unit cascaded after inductance L is connected with power network and form three-phase photovoltaic grid-connected electricity generation system；The quasi- Z of each two
Pass through inductance L between source inventer unitdConnection；The impedance network boosting unit is defined Z source impedance network boosting units；The
The n impedance network boosting unit of single-stage photovoltaic generating module is by inductance L2n-1, electric capacity C2nWith inductance L2nConnected by peripheral circuit
Composition is connect, wherein, n=1,2 and 3.
2. according to claim 1 based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：Often
Individual single-stage photovoltaic generating module also includes electric capacity of voltage regulation Cin, the electric capacity of voltage regulation CinIt is in parallel with photovoltaic cells.
3. according to claim 1 based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：Often
The ac converter unit of individual single-stage photovoltaic generating module is voltage source inverter VSI.
4. according to claim 1 based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：Also
Including dsp controller and Hall voltage sensor；The dsp controller is connected by Hall voltage sensor with power network.
5. according to claim 4 based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：Institute
Stating each single-stage photovoltaic generating module also includes that DC capacitor voltage sample circuit and quasi- Z-source inverter output voltage electric current are adopted
Sample circuit；Quasi- Z-source inverter unit in described each single-stage photovoltaic generating module passes through DC capacitor voltage sample circuit
It is connected with dsp controller；The output end of the quasi- Z-source inverter unit in described each single-stage photovoltaic generating module is by exporting electricity
Current voltage sample circuit is connected with dsp controller.
6. according to claim 4 based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：Institute
Stating each single-stage photovoltaic generating module also includes PWM drive circuit；The dsp controller is by PWM drive circuit and each list
Quasi- Z-source inverter unit connection in level photovoltaic generating module.
7. according to claim 4 based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：Institute
Stating each single-stage photovoltaic generating module also includes Hall current sensor；Power network in each single-stage photovoltaic generating module is by suddenly
You are connected current sensor with dsp controller.
8. according to claim 4 based on the grid-connected photovoltaic system for cascading quasi- Z-source inverter, it is characterised in that：Institute
Stating each single-stage photovoltaic generating module also includes photovoltaic cell voltage and current detection circuit；Described each single-stage photovoltaic generating module
In photovoltaic cells be connected with dsp controller by voltage and current detection circuit.
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| CN201621292017.XU CN206302163U (en) | 2016-11-29 | 2016-11-29 | A kind of grid-connected photovoltaic system based on the quasi- Z-source inverter of cascade |
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| CN201621292017.XU CN206302163U (en) | 2016-11-29 | 2016-11-29 | A kind of grid-connected photovoltaic system based on the quasi- Z-source inverter of cascade |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109194127A (en) * | 2018-10-25 | 2019-01-11 | 福州大学 | A kind of high-gain is wide to input double quasi- sources Z inverter circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109194127A (en) * | 2018-10-25 | 2019-01-11 | 福州大学 | A kind of high-gain is wide to input double quasi- sources Z inverter circuit |
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