A kind of grid-connected photovoltaic system with intelligent power dividing functionTechnical field
The present invention relates to technical field of photovoltaic power generation, especially a kind of to have the grid-connected of intelligent power dividing functionElectricity generation system.
Background technology
Photovoltaic cell is a kind of device having response to light by photoelectric effect and can convert light energy into electric power.Photovoltaic is sent outElectricity obtains broad development in recent years as one of most potential generation technology in all regenerative resources.
Parallel network power generation/power supply is photovoltaic generation application that is most widely used at present, being also maturation the most.It is grid-connectedThe most basic component parts that generates electricity includes mainly photovoltaic array, semiconductor rectifier, accumulator, grid-connection device or device.Wherein,Large-capacity battery is to adjust the necessary means of photovoltaic generation and AC network power energy allocation and load distribution, and grid-connection device is thenIt is photovoltaic generation and AC network comprehensive utilization ratio maximumlly one of adjustment means.
Currently, since photovoltaic array power generation amount is influenced by uncertain factor, and the load capacity that is incorporated into the power networks change it is big,Large-capacity battery in parallel network power generation is primarily present the problem of overcharging with charge less overload operation, and free charge and dischargeAccumulator cell charging and discharging under electricity condition is frequent.Therefore the accumulator activity in grid-connected photovoltaic system will be severely impacted,To substantially reduce service life and service efficiency, the safety of photovoltaic power generation grid-connecting operation is further influenced.Therefore, it is necessary to seekA kind of intelligent solution is sought, is overcharged and charge less problem to avoid accumulator in photovoltaic parallel in system.
In addition, current photovoltaic generation incoming transport power grid generally in such a way that semiconductor variable flow device is using parallel connection, i.e.,Photovoltaic generation provides means as the auxiliary power of main power grid.But it breaks down inside main power grid or photovoltaic generating systemWhen, parallel way above-mentioned will disintegrate, and photovoltaic generation and AC network respectively work independently again.Although in the prior artPropose the alternative solution that photovoltaic generation is incorporated into the power networks with series-parallel system.But the tandem working interface provided at present only existsIt just comes into operation in the case of exchanging main electric network fault, utilization ratio is low, and photovoltaic generation and AC network are in parallel or seriesPattern be it is fixed, cannot according to load capacity carry out intelligent maneuver adjusting.Therefore, it is also desirable to which providing one kind can flexibly turnBecome the interface arrangement of the series and parallel relationship between photovoltaic generation and AC network.
Invention content
The present invention is provided a kind of with intelligent power distribution to avoid shortcoming present in above-mentioned prior artThe grid-connected photovoltaic system of function, effectively to solve the problems, such as in a manner of its accumulator and grid integration.
The present invention proposes lower technical solution：
A kind of grid-connected photovoltaic system with intelligent power dividing function, is structurally characterized in that, includes mainly lightPhotovoltaic array, bridge rectifier, charge controller, Voltage stabilizing module, accumulator, bidirectional converter, selecting switch module, alternating currentNet；
The photovoltaic array is connected by the bridge rectifier with the charge controller；The charge controller withThe accumulator is connected；The charge controller and the accumulator are respectively by the Voltage stabilizing module and electrical equipmentDC load is connected；
The charge controller includes mainly microcontroller, auxiliary charging module, accumulator electric-quantity detection module；Wherein,The microcontroller is separately connected the auxiliary charging module, the accumulator, the Voltage stabilizing module；The auxiliary charging moduleIt is connected with the accumulator by the accumulator electric-quantity detection module；The auxiliary charging module is examined with electrical equipment powerModule connection is surveyed, the electrical equipment power detection module is used to detect the bearing power of electrical equipment；
The photovoltaic array is connected by the bridge rectifier with the bidirectional converter；The bidirectional converter withAC load in electrical equipment is connected, and the bidirectional converter is negative by the direct current in Voltage stabilizing module and electrical equipmentLoad is connected；
The AC network is connected by A.C. contactor with the selecting switch module, the selecting switch module withThe bidirectional converter is connected；The selecting switch module is used to control the string of the AC network and the bidirectional converterConnection is in parallel.
Further, the charge controller further includes photovoltaic power detection module, the photovoltaic power detection module withThe microcontroller is connected；
Further, the selecting switch module includes the first bi-directional thyristor switch, the second bi-directional thyristor switch, theThree bi-directional thyristor switch, in single-phase circuit, the first bi-directional thyristor switch includes two bidirectional triode thyristors in parallel, and secondBi-directional thyristor switch includes two bidirectional triode thyristors in parallel, and third bi-directional thyristor switch is a bidirectional triode thyristor.
Further, the selecting switch module also include a capacitor, the capacitor with the third is two-way canIt is in parallel to control transwitch.
Compared with the prior art, the present invention has the beneficial effect that：
A kind of grid-connected photovoltaic system with intelligent power dividing function of the present invention, by charge controllerMiddle setting auxiliary charging module, by realizing the automatic charging to accumulator to the detection of accumulator electric-quantity.It avoids to electric power storageThe overcharge in pond and charge less electricity, and the charge and discharge number to accumulator is effectively reduced, and then the use of accumulator can be extendedService life.
During solar recharging, electrical equipment is first checked whether there is in electricity consumption and electric power, further according to the sunEnergy charge power is allocated.If the electric energy that solar energy provides is more than the electric energy that electrical equipment uses, extra electric energy isAccumulator charges.If the inadequate electrical equipment of electric energy that solar energy provides uses, insufficient section is provided by accumulator.
External alternating current to charge the battery when, if solar energy also exports electric energy at this time, preferentially use solar recharging；It is insufficient in solar recharging, reuse commercial power charged function.
A kind of grid-connected photovoltaic system with intelligent power dividing function of the present invention, also passes through selecting switch mouldBlock controls AC network and photovoltaic system in parallel or series, can be according to load capacity or grid-connected photovoltaic systemFault condition such as automatically controls the parallel connection between photovoltaic system and AC network, connects at the states.
A kind of grid-connected photovoltaic system with intelligent power dividing function of the present invention, passes through auxiliary charging moduleIt realizes and the intelligent charge of accumulator is controlled, and the intelligence to photovoltaic system and AC network is realized by selecting switch moduleNetworked mode controls, and can effectively extend the service life of accumulator, improve grid-connected photovoltaic system electric energy service efficiency,The failure rate of grid-connected photovoltaic system can also be reduced simultaneously.
Description of the drawings
Fig. 1 is that a kind of overall structure with the grid-connected photovoltaic system of intelligent power dividing function of the present invention is formerReason figure.
Fig. 2 is the structure diagram of charge controller in the embodiment of the present invention.
Fig. 3 is the circuit diagram of selecting switch module in the embodiment of the present invention.
Below by way of specific implementation mode, and in conjunction with attached drawing, the invention will be further described.
Specific implementation mode
Referring to Fig. 1, it illustrates a kind of schematic diagrams of grid-connected photovoltaic system.
A kind of grid-connected photovoltaic system with intelligent power dividing function of the present invention, includes mainly photovoltaic battle arrayRow, bridge rectifier, charge controller, Voltage stabilizing module, accumulator, bidirectional converter, selecting switch module, AC network.LightPhotovoltaic array is connected by bridge rectifier with charge controller.Wherein, distributed photovoltaic unit composition can be used in photovoltaic array,Uncontrollable full-bridge Power Diode Pumped composition can be used in bridge rectifier.12V monomer lead-acid batteries composition can be used in accumulatorBattery pack, or use ultracapacitor.
As shown in Figure 1, charge controller is connected with the accumulator.Charge controller and accumulator pass through voltage stabilizing respectivelyModule is connected with the DC load in electrical equipment.The BOOST circuits with LC filters can be used in Voltage stabilizing module, have boostingFunction can provide stable power output for DC load.
Photovoltaic array is connected by bridge rectifier with bidirectional converter.Bidirectional converter in this example is different from existing" bidirectional converter " concept existing in technology, the bidirectional converter do not have the function that energy two-way circulates, only refer to direct current orAC energy can flow to the other end from one end, and can be changed into direct current or form of communication needed for load.The two-way changeAlthough the circuit of stream device is not expressed in the drawing of the present application, the basis based on those of ordinary skill in the art is knownKnowledge can be implemented, such as：By taking three-phase as an example, using the full bridge structure of electric power IGBT as the bidirectional converter of the present invention,By suitable pwm control signal, the direct current of one end or electric current income can be changed into exchange (direct current)/direct current of the other end(exchange) exports.
See Fig. 1, bidirectional converter be connected with the AC load in electrical equipment, and the bidirectional converter also byVoltage stabilizing module above-mentioned is connected with the DC load in electrical equipment.
AC network is connected by A.C. contactor with selecting switch module, selecting switch module and bidirectional converter phaseConnection.
During solar recharging, electrical equipment power detection module can check whether there is electrical equipment in electricity consumption andElectric power, while the power of solar energy output can also be detected by charge controller.Charge controller is according to solar charging electric workRate is compared with the realtime power of electrical equipment.If the electric energy that solar energy provides is more than the electric energy that electrical equipment uses,Extra electric energy is to charge the battery.If the inadequate electrical equipment of electric energy that solar energy provides uses, insufficient section is by electric power storagePond is supplied to electrical equipment.
External alternating current to charge the battery when, if solar energy also exports electric energy at this time, preferentially use solar recharging；It is insufficient in solar recharging, reuse commercial power charged function.
Referring to attached drawing 2, charge controller includes mainly microcontroller U1, auxiliary charging module, accumulator electric-quantity detection mouldBlock, photovoltaic power detection module.Wherein, microcontroller U1 is separately connected auxiliary charging module, accumulator, photovoltaic power detection mouldBlock, Voltage stabilizing module.Auxiliary charging module is connected by accumulator electric-quantity detection module with accumulator.Auxiliary charging module and useElectric equipment power detection module connects, and electrical equipment power detection module is used to detect the bearing power of electrical equipment.
In the present invention, microcontroller U1 is turned on and off the charging to accumulator according to the feedback signal of auxiliary charging moduleCircuit.Specifically it is realized in：Auxiliary charging module is made of two discrete integrating circuit, presets accumulator electricity respectivelyMeasure the corresponding analog signal values of upper and lower bound.Accumulator electric-quantity detection module detects the electricity of accumulator, and generation pair in real timeThe analog signal answered is sent to auxiliary charging module, and auxiliary charging module is by the ratio of the signal value of setting and real time detection signal valueRelatively result issues microcontroller U1, and the switching of charging circuit is controlled by microcontroller U1.Upper limit threshold can be set to prevent electric power storagePond overcharges, and lower threshold is arranged to prevent accumulator charge less electric.
Attached drawing 1 is seen again, and electrical equipment work(is arranged in one of the auxiliary as accumulator protecting in one embodiment of this inventionRate detection module includes the power detection to DC load in the electrical equipment power detection module.When accumulator electric-quantity is less thanWhen lower threshold, output of the microcontroller U1 cut-out accumulators to DC load directly controls bridge rectifier through regulator circuitIt powers to DC load.
Attached drawing 3 is with the circuit theory that single-phase circuit is the selecting switch module being illustrated in the present invention.It only describes belowThe circuit structure that single-phase circuit is related to.Selecting switch module includes three bi-directional thyristor switch K1, K2, K3 and a capacitanceDevice C.In single-phase circuit, the first bi-directional thyristor switch K1 includes two bidirectional triode thyristors in parallel, the second bidirectional triode thyristorSwitch K2 also includes two bidirectional triode thyristors in parallel, and third bi-directional thyristor switch K3 is a bidirectional triode thyristor.
It can also be mechanical switch that switch K, which can be A.C. contactor, in Fig. 3, and when switch K is disconnected, photovoltaic system is detached fromPower grid independent operating.In the present embodiment, switch K is set as contact normally off.
Selecting switch module in the present invention can realize that (its output end is Bidirectional variable-flow to photovoltaic system according to control signalDevice) switch with the connection in series-parallel of AC network：First bi-directional thyristor switch K1 is disconnected, the second bi-directional thyristor switch K2 and thirdWhen bi-directional thyristor switch K3 conducting, photovoltaic system realizes series operation with AC network, at this point, AC network is to AC loadPower supply, photovoltaic system are powered to DC load, or control bidirectional converter is born to direct current simultaneously from photovoltaic system and AC networkCarry power supply.Second bi-directional thyristor switch K2 is disconnected, and the first bi-directional thyristor switch K1 and third bi-directional thyristor switch K3 are ledWhen logical, photovoltaic system realizes parallel running with AC network, at this point, photovoltaic system is powered to DC load, photovoltaic system and friendshipGalvanic electricity net is powered to AC load simultaneously.
Certainly, selecting switch module of the invention and bidirectional converter cooperating, additionally it is possible to realize other functions, such as simultaneouslyJoin under operational mode, control bidirectional converter can realize that AC network charges to accumulator.
Again referring to attached drawing 2, charge controller further includes photovoltaic power detection module, if the output power of photovoltaic array is more thanPower needed for electrical equipment (direct current+exchange), i.e. the output electricity of photovoltaic array has surplus, at this time if examined by accumulator electric-quantityThe electricity for surveying the accumulator of module feedback is discontented (upper limit threshold for not arriving setting), then the microcontroller U1 in charge controllerStart charging circuit to charge to accumulator；If accumulator electric-quantity has been expired at this time, switched via microcontroller U1 control selectionsModule selectes parallel running mode, and control bidirectional converter exports electric energy to AC network.If the output power of photovoltaic array is smallThe power needed for electrical equipment is then electrical equipment by the output circuit of the microcontroller U1 starting storage batteries in charge controllerIn DC load power supply.At this point, if accumulator electric-quantity is insufficient (being less than given threshold), by microcontroller U1 control selectionsSwitch module starts the serial or parallel connection pattern of AC network.
The photovoltaic power detection module includes voltage detecting circuit and current detection circuit；The voltage detecting circuit is usedIn the output voltage for detecting the bridge rectifier, it is used to detect the output current of bridge rectifier for current detection circuit.
It is obvious to a person skilled in the art that invention is not limited to the details of the above exemplary embodiments, Er QieIn the case of without departing substantially from spirit or essential attributes of the invention, the present invention can be realized in other specific forms.Therefore, no matterFrom the point of view of which point, the present embodiments are to be considered as illustrative and not restrictive, and the scope of the present invention is by appended powerProfit requires rather than above description limits, it is intended that all by what is fallen within the meaning and scope of the equivalent requirements of the claimsVariation is included within the present invention.Any reference signs in the claims should not be construed as limiting the involved claims.
In addition, it should be understood that although this specification is described in terms of embodiments, but not each embodiment is only wrappedContaining an independent technical solution, this description of the specification is merely for the sake of clarity, and those skilled in the art shouldIt considers the specification as a whole, the technical solutions in the various embodiments may also be suitably combined, forms those skilled in the artThe other embodiment being appreciated that.