CN102270850B - Solar energy photovoltaic system - Google Patents

Abstract

The present invention describes a kind of photovoltaic power generation system, and this system includes: at least two pieces of photovoltaic panel, and each piece of photovoltaic panel has the output of DC power；Power adjustment unit, it has the input of DC power and AC main supply power exports, and is used for providing AC main linely connected power sup ply；The described DC power output of wherein said at least two pieces of photovoltaic panel is connected in parallel with each other to the described DC power input of described power adjustment unit；Wherein said power adjustment unit include having coupled to the input of described DC power input and have the DC link coupleding to described power adjustment unit output DC to DC transducer, have and coupled to the input of described DC link and there is DC to the AC transducer of the output coupleding to the output of described AC main supply and coupled to the energy-storage capacitor of described DC link；And the configuration of wherein said power adjustment unit is to perform maximum power point tracking (MPPT) in response to the power level flowing into the input of described DC power, and wherein at described DC link, sensing flows into the described power level of described DC power input.

Description

Solar energy photovoltaic system

Technical field

The present invention relates to the improvement technology using maximum power point tracking (MPPT) to produce photovoltaic power.

Background of invention

Relate to the background technology of solar converter and MPPT, generally can find in the following literature: EP0780750A；JP2000020150A；US2005/0068012；JP05003678A；GB2415841A；EP0947905A； WO2006/011071；EP1,235,339A；WO2004/006342；DE10064039A；US2005/030772；WO96/ 07130；US6,657,419；US2004/117676；US2006/232220；WO2004/001942；GB2419968A；US7, 319,313；US7,450,401；US7,414,870；US7,064,967；P.T. the technical papers of Kerin and R.S.Balog “Cost-Effective Hundred-YearLife for Single-Phase Inverters and Rectifiers in Solar and LED Lighting ApplicationsBased on Minimum CapACitance Requirements And a Ripple Power Port ": US2009/0097283；C.Rodriguez and G.A.J.Amaratunga was in 2008 " the Long-Lifetime Power Inverter for of page 55 (7) the 2593rd of IEEE Trans IE Photovoltaic AC Modules”；And US2008/097655.

The improvement technology that we have described the maximum power point tracking for solar converter (MPPT) (sees me In on March 19th, 2010 submit to GB Patent Application No. No.1004621.7 and on May 27th, 2010 submit to US 12/789,154.Having recognized that, these technology contribute to feasibly using new solar energy photovoltaic system to construct.

Summary of the invention

Thus, according to a first aspect of the present invention, it is provided that a kind of photovoltaic power produces system, this system includes: at least two Block photovoltaic panel, each piece of photovoltaic panel has the output of DC power；Power adjustment unit, it has the input of DC power and AC main supply Power exports, and is used for providing AC main linely connected power sup ply；The described DC power of wherein said at least two pieces of photovoltaic panel exports the company of being connected in parallel to each other It is connected to the described DC power input of described power adjustment unit；Wherein said power adjustment unit includes having and coupled to described DC The input and having of power input coupled to DC to the DC transducer of the output of the DC link of described power adjustment unit, has Coupled to the input and having of described DC link coupled to the output of described AC main supply output DC to AC transducer, with And it coupled to the energy-storage capacitor of described DC link；The configuration of wherein said power adjustment unit is with in response to flowing into described DC power Input power level and perform maximum power point tracking (MPPT), and wherein at described DC link sensing flow into described DC The described power level of power input.

In a related aspect, the invention provides a kind of photovoltaic power and produce system, this system includes: at least two blocks of light Volt plate, each piece of photovoltaic panel has the output of DC power；Power adjustment unit, it has the input of DC power and AC main supply power Output, is used for providing AC main linely connected power sup ply；Wherein said at least two pieces of photovoltaic panel described DC power output be connected in parallel with each other to The described DC power input of described power adjustment unit；Wherein said power adjustment unit includes for storage from described photovoltaic The energy-storage capacitor of the energy of plate, and have coupled to described energy-storage capacitor DC input and coupled to described AC do DC to the AC transducer of the AC output of line power supply output；Wherein said power adjustment unit includes controller, and this controller couples To control described DC to AC transducer to perform maximum power point tracking (MPPT)；Wherein said controller has sensing input, It coupled to described energy-storage capacitor, with the power level in response to the described DC power input flowing into described power adjustment unit And at this energy-storage capacitor described sensing signal, wherein said controller is configured to by response at described storage capacitor The described power level of the described DC input flowing into described power adjustment unit sensed at device, controls described DC to AC conversion Device is to control to inject the power of described AC main supply, and performs described MPPT.

Broadly, inventor has recognised that by chaining use energy-storage capacitor at DC, and by based on The power stream that senses at this link and perform maximum power point tracking (MPPT), can use two pieces or polylith is connected in parallel The solar energy photovoltaic panel of (i.e. positive pole is connected by positive pole, and negative pole anticathode connects), and still realize from plate (or more) Almost obtain optimal power: test is it has been shown that according to embodiments of the invention, for the plate of a pair parallel connection, for Every block of plate carry out respectively the MPPT of MPPT and combination follow the trail of between performance difference the most only 1% the order of magnitude, even at the moon The when that shadow effect etc. existing.

Other advantages of the embodiment of the present invention are, owing to generally only needing the relatively small dilatation (up-of transducer Rating), such as by increase energy-storage capacitor value about 30%, for be up to about 350 watts AC power export and up to than Such as 36 μ F, almost make the approximation AC main line power of every watt produce cost and halve.And usually, use bigger input power, Power adjustment unit (transducer) runs can more effectively, and this is partially due to the fixed overhead of power needed for internal circuit (this is especially pronounced for microcolumn Gel immunlassay).In consideration of it, provide input from the plate that two pieces or polylith are in parallel, trend towards unclear Situation under maintain input power average, for example, maintain transducer to be in more effective operational mode.

In some preferred embodiments, power adjustment unit follows the trail of MPPT, and without directly measuring D/C voltage or electricity from plate The most as an alternative, at DC link sensing voltage (rather than electric current), energy-storage capacitor is connected to described DC chain to stream Connect.In certain embodiments, as described in more detail below, controller senses the level of the pulsating volage at this link, with sense Flow measurement crosses the middle power stream of DC link, and in the case of there is not loss, its measurement flow to power adjustment unit from photovoltaic panel Combination DC input power flow.In an embodiment, controller control DC to AC transducer with maximize pulsating volage and thus This middle power stream, thus maximize from this combination DC input power to solar energy photovoltaic panel.In a preferred embodiment, will DC to the DC transducer that substantially amplitude is substantially stationary is connected between the input of power adjustment unit and DC link, to provide base Amplification factor fixing in basis, increases to intermediate dc voltage by the input D/C voltage of plate, typically larger than 100 volts, 200 volts, 300 Volt, 400 volts or 500 volts.

Some being constructed, by sensing at DC link as mentioned above, even if being not carried out MPPT, using two pieces or polylith Parallel plate is also advantageous.This is especially for microcolumn Gel immunlassay, and it is to be exclusively used in one piece or the transducer of a small part PV plate.

Thus, in another aspect of the invention, it is provided that a kind of photovoltaic power produces system, this system includes: at least two pieces Photovoltaic panel, every piece of photovoltaic panel has the output of DC power；Power adjustment unit, it has the input of DC power and for providing AC to do The AC main supply output of line power supply；The described DC power output of wherein said at least two pieces of photovoltaic panel is connected in parallel to each other, and is connected to The described DC power input of described power adjustment unit；Wherein said power adjustment unit includes DC to DC transducer, Yi Jiwei Described DC power in described power adjustment unit inputs the DC link between the input of described DC to DC transducer, Qi Zhongsuo State DC to AC transducer and there is the output coupleding to the output of described AC main supply, and wherein said power adjustment unit also wraps Include the energy-storage capacitor coupleding to described DC link；Wherein said energy-storage capacitor is non-electrolytic capacitor；And wherein said merit Rate regulation unit is configured in response to the power level flowing into the input of described DC power, and performs maximum power point tracking (MPPT)。

Owing to signal component value is along with the mode of changed power, the embodiment of above-mentioned power regulating system can provide generation every watt The saving of the cost-effectively of special power.In particular, it is positioned at DC link due to energy-storage capacitor, it is also possible to use relatively small Non-electrolytic capacitor (see also our WO2007/080429, described document is hereby incorporated by reference).Have at DC link Having storage capacitor, even if when two pieces or polylith PV plate parallel connection, required energy storage is the most relatively low.And, even if MPPT is not It is optimized, owing to microcolumn Gel immunlassay can physically be located close to its PV plate being connected to, still can reduce connection cable On pressure drop (this is extremely important), and this contributes to any deficiency of alleviating in MPPT.

Some preferred embodiments of said system use controller to control to inject the AC current amplitude of AC main line, thus its Substantially the most linearly, depend on or the amplitude of the sine component of pulsating volage that is proportional on storage capacitor (mains frequency Twice).More particularly, by controlling DC to AC transducer, control to inject the AC electric current of main line, and at some preferred embodiments In, identical controller performs MPPT, by the voltage on sensing storage capacitor, and controls the electric current injected.Possibly, permissible Use transformerless power control unit (transducer), but in a preferred embodiment, power adjustment unit includes DC in front end To DC transducer, as previously mentioned.For wherein based on sense pulsating volage level at DC link and control to inject AC main line The embodiment of electric current, use and input DC to the DC transducer between DC link at the DC of power adjustment unit, it is provided that Mode easily, allows to exist on storage capacitor pulsation when there is not pulsating volage with the DC input at power adjustment unit Voltage.

In related fields, the invention provides the method producing AC main supply from polylith photovoltaic panel, the method includes: DC power output-parallel from described photovoltaic panel is connected to the input of power adjustment unit；Use described power adjustments list Unit, using described power supply and change the circulation of described DC power into described AC main supply, wherein said conversion includes DC power The described inlet flow of unit is converted in the middle of the DC power at the DC link of the described power adjustment unit coupleding to storage capacitor Stream, and the described intermediate flow of DC power is converted into described rail current；And substantially follow the trail of the described public of DC power The maximum power point of inlet flow.

As it was previously stated, in the reality by sensing middle power stream rather than using MPPT to follow the trail of in the front end of power adjustment unit Executing in example, embodiments of the invention substantially maximise the group to (or more) from the solar energy photovoltaic panel being connected in parallel Close DC input power flow.

Present invention also offers the system for producing AC main supply from polylith photovoltaic panel, this system includes: being used for will DC power output-parallel from described photovoltaic panel is connected to the input of power adjustment unit to provide the public stream of DC power Device；For using described power adjustment unit the circulation of described DC power to be shifted to into the device of described AC main supply, wherein Described conversion includes the DC chain that the described inlet flow of DC power is converted into the described power adjustment unit coupleding to storage capacitor The DC power intermediate flow connected；For the described intermediate flow of DC power being converted into the device of described AC main supply；And use Device in the maximum power point of the described public inlet flow following the trail of substantially DC power.

In the embodiment of said system, it is preferable that one piece of photovoltaic panel is directly parallel-connected to another block photovoltaic panel, its Not there is middle series board.Being connected in parallel of plate can at power adjustment unit interiorly or exteriorly.However, it is likely that, although ratio Less preferably, two pairs of photovoltaic panel can be connected in series, be then connected in parallel plate pair.But, this ratio less preferably, because if One block of plate is the most shielded or breaks down and causes voltage drift, and MPPT can not correctly run.

As it was previously stated, the embodiment of the technology of our description is particularly suitable to so-called microcolumn Gel immunlassay.Microcolumn Gel immunlassay can be determined Justice is adapted to be coupled to be less than AC main line less than transducer and/or the DC input voltage of 10 pieces or less than 5 blocks plates for rated power The half of peak-to-peak voltage, more typically less than 100 volts of DC or the transducer less than 60 volts of DC.

The preferred embodiment of system provides single-phase AC, and the technology that we describe is not limited to for single-phase AC main line electricity Source, and also can apply to provide the photovoltaic power of three-phase AC main supply to produce system.In the latter case, preferably adopt With one DC to AC transducer of each phase place.

Maximum power point tracking

In order to help to understand the operation of the embodiment of the present invention, we will be first with broad terms, then use detailed art now Language describes the preferred implementation of the MPPT for above-mentioned solar energy photovoltaic system structure.

Therefore, for broader term, for providing power to have maximum to what AC main supply exported from the DC energy Power points follows the trail of the preferred power adjustment unit of (MPPT), including: input, for receiving power from the described DC energy；Output, uses In AC power being delivered to described AC main supply；Storage capacitor, for storage from the energy of the described DC energy, is used for delivering Export to described AC main supply；DC to AC transducer, coupled to described output, for will be stored in described storage capacitor Energy is converted into the AC power for the output of described AC main supply；Power injects control module, has and coupled to described energy storage The sensing input of electric capacity, and has the output coupleding to described DC to AC transducer, with control described DC to AC transducer with Control to inject the power of described AC main supply；And wherein said power injects control module and configures to follow the trail of the described DC energy Maximum power point, and without measure from the described DC energy provide D/C voltage or DC electric current.

In an embodiment, the voltage on storage capacitor has a sinusoidal voltage composition (twice of AC mains frequency), and power Inject the amplitude of the AC electric current that control module configuration provides to the output of AC main supply with control, thus transmission is to the power exported Amount depends on the amplitude of the sinusoidal voltage composition on storage capacitor.In an embodiment, the average energy transmitted depends on linearly In, be more particularly to be proportional to the square value of sinusoidal voltage composition.In an embodiment, sinusoidal voltage composition is superimposed upon DC link electricity Press (inputting to DC-to-AC transducer), and this link voltage is of a relatively high, e.g., less than 200,300,400 or 500 volts. In such embodiments, peak value (maximum) capacitance voltage that the mean power transmitted is proportional to square and square valley Difference between (minimum) capacitance voltage (but alternatively, power adjustment unit can arrange thus on an average, in energy storage It it is zero D/C voltage on electric capacity.In an embodiment, transmission is depended on to the instantaneous power of AC main supply output or is proportional to energy storage The instantaneous value of the voltage on electric capacity.

Thus, we also describe the power adjustment unit also with maximum power point tracking (MPPT), for by power from The DC energy is delivered to the output of AC main supply, and this power adjustment unit includes: input, for receiving power from the described DC energy； Output, for being delivered to described AC main supply by AC power；Storage capacitor, for storing the energy from the described DC energy, Export for delivery to described AC main supply；DC to AC transducer, coupled to described output, is used for will be stored in described energy storage Energy in electric capacity is converted into the AC power for the output of described AC main supply；Power injects control module, has and coupled to The sensing input of described storage capacitor, and there is the output coupleding to described DC to AC transducer, to control described DC to AC Transducer is to control to inject the power of described AC main supply；And wherein, in operation, the tool of the voltage on described storage capacitor There is the sinusoidal voltage composition of the frequency twice of described AC main line；Wherein said power injects control module configuration to control to provide extremely The amplitude of the AC electric current of described AC main supply output, thus the quantity of power that transmission exports to described AC main supply depends on institute State the amplitude of described sinusoidal voltage composition on storage capacitor, and wherein said power injects control module configuration with by control Make described DC to AC transducer and follow the trail of the maximum power point of the described DC energy.

In above-mentioned power adjustment unit, the energy flowing to storage capacitor from the DC energy is substantially proportional to storage capacitor Energy change amount (this will be explained further later).And, extract from storage capacitor and provide to the output of AC main line The amount of energy, is injected control module by power and is controlled, thus the AC quantity of power being delivered to AC main supply depends on storage The amount of the energy in storage capacitor.In this set, power setting control module it is possible to be turned by control DC to AC Parallel operation and control to be delivered to the AC power of AC main supply and follow the trail of the maximum power point of the DC energy, and without at power adjustments list The front end of unit uses MPP to follow the trail of, and it generally includes DC to DC transducer.For broader term, in the first scenario, merit Rate infusion circuit obtains power from the DC energy, and delivers it to storage capacitor.In the latter case, power infusion circuit Obtain energy from storage capacitor, and deliver it to AC output.AC power is delivered to the demand of output on storage capacitor Form sinusoidal voltage composition, and this is the intrinsic part in this control loop；Generally in operation, on storage capacitor (generally For DC) this fluctuation sinusoidal part of voltage have at least 10 volts, 20 volts, 30 volts, 40 volts, 50 volts, 60 volts or The peak amplitude of 100 volts.The peak amplitude of this sinusoidal voltage composition depends on the electric current injecting the output of AC main line.

If the DC input at power control unit will implement MPPT, such as by means of being positioned at front end DC to DC transducer Control loop, MPPT tracing algorithm will substantially on DC input voltage apply fluctuation degree to power adjustment unit, in order to The running point of the DC energy can change, thus to determine that peak power operates point.Operating point changes according to the energy in storage capacitor Become and automatically adjust.On the contrary, in an embodiment, we have employed " extraction " and arrange, wherein power when requiring effectively from The DC energy flow to storage capacitor, and this requirement is controlled by the second power and injects control loop.

In more detail, the fluctuation degree that DC chains, especially fluctuating margin, is quantity of power effective extracted from DC input Measure.If fluctuation decreases, it means that provide less power from DC input, and in the broadest sense, power injects control Molding block is subsequently by reducing the electric current injecting power transmission network (grid), say, that respond by adjusting power injection.In reality Execute in example, by adjusting the conversion speed regulation electric current of output DC to AC transducer.When system tracks maximum power point, if Power from DC input reduces, then fluctuation reduces, and regulates downwards the conversion speed of transducer, with by less electric current Inject in power transmission network.Operating point band is back to maximum power point by this, and make quantity of power that the DC energy provides with have been injected into defeated The quantity of power balance of electrical network.Control module the most periodically increases the conversion speed of power injection module, in order to increase stream Enter the magnitude of current of power transmission network.Its effect is when the amount of the energy provided by DC source is more than the amount just obtained, and increases fluctuation, and Thus control loop and effectively operate so that the energy maximization that fluctuates and the most gathered in the crops.According to typical I-V feature (seeing Fig. 9, after a while), this, corresponding to the servo near maximum power point, moves curve more particularly along characteristic curve, is reducing Electric current and increase alive (example as just now mentioning) direction or towards maximum power point increase electric current and reduce electricity The direction of pressure.

In an embodiment, power injects control module generation and injects the AC electric current template of main line.Especially, this template include with The synchronous sine of power transmission network main line or semisinusoidal voltage, and the amplitude of this template is according to the DC link pulsating volage recorded Adjust, more particularly, the most whether rise or fall according to it.Thus, the amplitude response of this template signal is in storage capacitor/DC The pulsating volage chained.Depend on the mistake of the difference having been injected between the AC electric current of power transmission network main line and this template recorded Signal is used for controlling power and injects the conversion speed of control module.In an embodiment, if template amplitude is more than having been injected into The amplitude of the electric current of AC main line, rub-out signal is used for increasing conversion speed.Since so, the electric current of injection is controlled to be easy to make The fluctuation of storage capacitor/DC link maximizes.

As it was previously stated, in some preferred implementations, use the fluctuating margin at storage capacitor/DC link, to have The power provided from DC source (photovoltaic panel) is measured on effect ground.But in principle, it is possible to use other technologies to measure storage capacitor/DC The power provided at link, from the DC energy.Such as, in the case of there is not loss, it can be assumed that the power that power supply provides, by electricity Pressure and flow through DC link and to DC to AC transducer provide input electric current product given by.But, due to our power The preferred implementation of regulation unit has the fluctuation being proportional to input power (assuming that input is substantially the same with output), Measuring fluctuation is the Advantageous techniques obtaining power demand information.

Thus we are described in for being delivered to the power adjustment unit of AC main supply output from the DC energy by power Carrying out the correlation technique of maximum power point tracking (MPPT), this power adjustment unit includes storage capacitor, for storage from institute Stating the energy of the DC energy, export for delivery to described AC main supply, the method includes: will by controlling DC to AC transducer The energy being stored in described storage capacitor is converted into the AC power for the output of described AC main supply, and follows the trail of described DC energy The maximum power point in source；At the current node coupleding to described storage capacitor, sense in response to obtaining from the described DC energy The signal of power level；And control described DC-extremely-AC transducer, to adjust the amplitude of AC output, substantially to maximize institute State sensing signal.

In an embodiment, record the signal that storage capacitor/DC chains, and be used for obtaining control (template) signal, its Amplitude depends on the power level obtained from the DC energy, particularly depends on the change of this power level sensed.Subsequently, base Difference between the AC electric current sensed and this control signal, controls the conversion speed of DC to AC transducer, especially works as control When signal processed (template) is more than the AC current signal sensed, increasing the conversion speed of output translator, vice versa.

Preferably, including D/C voltage amplifier stage between the input of DC power and the output of AC main line, this level has substantially permanent I.e. it is not changed fixed amplification factor by performing the control loop of MPPT, but in an embodiment, constant amplification because of Son can such as be chosen according to environment of operation.In an embodiment, it is provided that voltage amplification control module, but be not configured to carry Amplify for variable voltage and control loop, but effectively act as on and off switch, flow to DC-from input opening or closing power Path to-DC transducer.Alternatively, depend on that the embodiment of voltage amplifier stage, voltage amplification control module can provide (space factor of substantial constant) pulse width modulation controls signal to D/C voltage amplifier.

Being provided with of the above-mentioned type help DC input and AC main supply export between insulation because MPPT can be performed Follow the trail of, and without being connected directly to DC input, for measuring the voltage from the DC energy and/or electric current.

In an one example implementation, DC to AC transducer can include buck stages (buck stage) transducer, or Person alternatively, such as, can use " the stretching, extension bridge " combined with a pair power switching device and outputting inductance (" unfolding bridge "), such as described in our US7626834 (which is hereby incorporated by reference).In embodiment In, power injects control module and can be configured to sense the voltage on (DC link) storage capacitor so that it is reduce in proportion, and And it is sinusoidal wave to be multiplied by (appropriate phase), with drawing template establishment signal, for believing with the sensing obtained from power transmission network main line Number compare, in order to control the output electric current of DC to AC transducer.In an embodiment, it is not necessary to perform DC current sense.Implementing In example, power adjustment unit can include anti-isolated function, such as such as our Copending U.S. Application 10/555803 (WO2004/100348) (which is hereby incorporated by reference) described in.In some preferred embodiments, storage capacitor is non-electrical Solve electric capacity, such as thin film, polyester or polypropylene capactive；Electric capacity can have less than 50 μ F, 40 μ F, 30 μ F, 20 μ F or 10 μ F Value.

We also describe a kind of at the power adjustment unit for power is delivered to the output of AC main supply from the DC energy In the method for maximum power point tracking (MPPT), this power adjustment unit includes storage capacitor, for storage from described DC The energy of the energy, exports for delivery to described AC main supply, and the method includes: will storage by controlling DC to AC transducer The energy collected at described storage capacitor is converted into the AC power for the input of described AC main supply, and follows the trail of the described DC energy Maximum power point, wherein perform described tracking, and without measuring the D/C voltage or DC electric current provided from the described DC energy.

We further describe a kind of at the power adjustments list for power to be delivered to the output of AC main supply from the DC energy The method of the maximum power point tracking (MPPT) in unit, this power adjustment unit includes storage capacitor, for storage from described The energy of the DC energy, exports for delivery to described AC main supply, the most in operation, and the voltage tool on described storage capacitor Having the sinusoidal voltage composition of the doubled frequency of described AC main line, the method includes: control the AC provided to the output of AC main supply The amplitude of electric current, thus transmission to the quantity of power that described AC main supply exports depends on described sinusoidal electricity on described storage capacitor The amplitude being pressed into point, wherein, will be stored in the energy that described storage capacitor collects be converted into use by controlling DC to AC transducer Perform described control in the AC power of described AC main supply input, and follow the trail of by controlling described DC to AC transducer The maximum power point in described DC source.

In the broadest sense, in the embodiment of these methods, change the voltage pulsation sine on (DC link) storage capacitor and become Branch changes the voltage of the input from the DC energy, and forces electric current (from the DC energy) follow voltage and change, with symbol Close the current-voltage characteristics curve of the DC energy.If obtaining power from DC link, and provide to the output of AC main line, energy storage electricity D/C voltage in appearance declines, and DC input voltage declines (vice versa) therewith.Thus, in embodiment of the method, can adopt With the voltage on (only) sensing storage capacitor, to control the electric current at power adjustment unit and voltage.

Can use and implement these methods, code with the processor control routine implementing these methods for controlling processor Can be stored on the carrier of such as non-volatile storage.

Accompanying drawing explanation

To be only used as exemplary reference annexed drawings and further describe these and other aspects of the present invention, wherein now:

Fig. 1 shows the example power adjustments list being adapted for carrying out MPPT tracing system according to an embodiment of the invention Unit.

Fig. 2 shows the details of suitable power adjustment unit in Fig. 1.

Fig. 3 shows the DC capacitance voltage in the power adjustment unit of Fig. 1.

Fig. 4 shows control module A in the power adjustment unit of Fig. 1.

Fig. 5 shows the example characteristic curve of photovoltaic panel array as known in the art.

Fig. 6 shows control module B in the power adjustment unit of Fig. 1.

Fig. 7 shows control module A of the power adjustment unit for Fig. 1 and the details of the example of B.

Fig. 8 shows output and the input power of the power adjustment unit for Fig. 1.

Fig. 9 shows that the example output current-voltage characteristics of the photovoltaic panel of the position (X) of instruction peak power output point is bent Line.

Figure 10 shows that the photovoltaic power including MPPT tracing system according to an embodiment of the invention regulates unit The structure chart of example DC importation.

Figure 11 shows that the photovoltaic power including MPPT tracing system according to an embodiment of the invention regulates unit The structure chart of example AC output part.

Figure 12 shows that the photovoltaic power including MPPT tracing system according to an embodiment of the invention regulates unit The circuit diagram of example DC importation.

Figure 13 shows that the photovoltaic power including MPPT tracing system according to an embodiment of the invention regulates unit The details of example AC output part.

Figure 14 shows that the photovoltaic power including MPPT tracing system according to an embodiment of the invention regulates unit Voltage on DC link capacitance voltage, it is shown that the sine component of voltage.

Figure 15 shows the merit of the power adjustment unit according to an embodiment of the invention with maximum power point tracking Rate is injected the example of control module and is controlled program.

Figure 16 a and 16b shows the first He of photovoltaic power generation system structure according to embodiments of the present invention Second example.

Figure 17 shows one group of output current-voltage characteristics curve of photovoltaic panel, indicates the most maximum defeated Go out the change of the position (X) of power operation point.

Figure 18 a and 18b respectively illustrates the exemplary internal circuit of PV plate and photovoltaic power generation system again One less preferably constructs.

Figure 19 shows three phase place examples of photovoltaic power generation system according to an embodiment of the invention.

Detailed description of the invention

Power adjustment unit

First we describe the example of photovoltaic power regulation unit, in embodiment, it can be advantageous to use our institute MPPT (maximum power point tracking) technology stated.

Thus, first we will describe a kind of method controlling DC power supply, and especially a kind of control uses power electricity Sub-transducer and input power is adjusted to provide the method for DC source of the AC electrical power to main line.This power electronic Transducer includes polylith switching stage, and takes the accumulator of capacitive form.Described method allow use long-life polyester or Polypropylene capactive, rather than short-life electrochemical capacitor.The method uses two kinds of control algolithms: a kind of algorithm controls is extracted from power supply Power, its will provide to accumulator；And power is transmitted to feeder cable by another algorithm controls from accumulator.

In one is arranged, it is provided that a kind of power adjustment unit, for power is delivered to AC main line electricity from the DC energy Source exports, and this power adjustment unit includes: power adjustment unit inputs, for receiving power from the described DC energy；Power adjustments Unit output is used for delivering AC power；Energy-storage capacitor；DC to DC transducer, it has, and to coupled to described power adjustment unit defeated The input entered connects and coupled to the output connection of described power adjustment unit output；DC to AC transducer, it has coupling Input to described energy-storage capacitor connects and is coupled to the output connection of described power adjustment unit output；Wherein said energy storage Electric capacity is non-electrolytic capacitor；And wherein said power adjustment unit includes that two pieces of control modules, the first power draw control mould Block for controlling described DC to DC transducer to control to extract and the power that provides to described storage capacitor from the described DC energy, And the second power injects control module and is used for controlling described DC to AC transducer to control to inject described AC from described storage capacitor The power of main supply；And wherein said power draw control module has input, and it coupled to described power adjustment unit Input, for receiving power from the described DC energy, and also it is to-DC transducer and described to control described DC-to have output The configuration of power draw control module is to regulate the voltage on the described DC energy, to control to extract to described energy storage from the described DC energy The power of electric capacity.

The output of AC main supply can be connected to general-purpose power transmission network, thus power is delivered to power transmission network by power adjustment unit In, or it can be the output of independent power supply, for providing power to electrical equipment.

DC to AC transducer can configure substantially sinusoidal curtage is delivered to the output of AC main supply, and Do not consider the voltage on storage capacitor.This can be by being maintained essentially at reference by the curtage being delivered to power supply output Sinusoidal current or voltage and realize.This can include in response to from storage capacitor voltage or electric current or be delivered to power supply output Curtage, and control the transistor in DC to AC transducer.

Storage capacitor can include non-electrolytic capacitor, such as film type electric capacity (such as polyester or polypropylene).Capacitance can To be directly proportional to the rated power of maximum power transfer ability, i.e. device.This value can be less than having same nominal power Capacitance in ordinary power regulation unit.Such as, less than 20 microfarads, less than 15 microfarads, less than 10 microfarads, less than 5 Microfarad or non-electrolytic capacitor another data attainable.

We also will describe a kind of DC to DC transducer, for power is delivered to DC output, this transducer from the DC energy Configuring substantially constant on a range of output voltage with the voltage on the maintenance DC energy, transducer includes for from described The DC energy receives the input of power, for delivering the output of DC power, for power is transmitted at least to output from input Individual power apparatus, for sensing the sensing circuit of voltage in described input and described for driving in response to described sensing At least one power apparatus is to control the drive circuit of described power transmission.

We also by describe a kind of for by power from the DC energy be delivered to AC output transducer, this transducer configuration with Maintaining substantially sinusoidal output voltage or electric current on a range of DC energy source voltage, this transducer includes for from described The DC energy receives the input of power, for delivering the output of DC power, for power is transmitted at least to output from input Individual power apparatus, coupled to described input low pass filter, for sensing from low pass filter output and with reference The sensing circuit that value compares, and be used in response to described sensing to drive at least one power apparatus described to control described merit The drive circuit of rate transmission.

We also will describe a kind of power adjustment unit for power is delivered to the output of AC main supply from the DC energy, Wherein power adjustment unit link electric capacity be connected in parallel described power adjustment unit DC to DC transducer output and Between the input of DC to the AC transducer of described power adjustment unit, itself and non-electrolytic capacitor.

We also will describe a kind of method controlling power adjustment unit, and it is for being delivered to AC electric power by power from DC source Supply, this power adjustments includes: for connecting the input of the DC energy；For connecting the output of supply of electric power；Oneth DC to DC merit Rate switching stage, for carrying out voltage-regulation to the DC energy；Second power conversion stage, for injecting AC supply of electric power by power；With And DC links storage capacitor, for carrying out energy snubber from the DC energy to supply of electric power；Wherein the method includes controlling described Two power conversion stage are to control to provide the amplitude of the AC electric current to described AC supply of electric power, thus transmission is to described AC main supply The quantity of power of output depends on the peak amplitude of the fluctuation sine component of described storage capacitor row D/C voltage.

Thus, example power adjustment unit use one for control by power from DC energy source to electric mains System, the described DC energy such as solar panel, fuel cell, DC wind turbine etc., and especially permission is long-lived Order polyester or polypropylene capactive and replace short life accumulator.

Energy hole and MPPT technique that we describe may be used for any power electronic converter as shown in Figure 1 and set Standby 1.This device 1 includes three main elements: power converter level A3, a storage capacitor C_dc4 and a power converter Level B 5.Device 1 has the polylith input being connected to direct current (DC) source, such as includes or many connecting and/or being connected in parallel The solar energy in block DC source or photovoltaic panel array 2.Device 1 is additionally coupled to supply of electric power 6, thus is passed by the energy extracted from DC source 1 It is input into into main line 6.

Power converter level A 3 can have dissimilar: it can be to decline transducer, wherein uses some power electricity Subtopology and reduce the voltage of input；It can be to rise transducer, wherein use different types of power electronic circuit and Amplify input voltage；Or its input voltage that can amplify simultaneously and decay.Additionally, it can couple by means of transformator or Inductance, and provide electric insulation.No matter which kind of situation, the electrical adjustment of input voltage should make C on electric capacity_dcThe voltage of 4 begins It is maintained above the amplitude of power transmission network voltage 6 eventually.Additionally, this module comprises one or polylith transistor, inductance and electric capacity.Pass through arteries and veins Rush width modulated (PWM) generator and drive transistor.Pwm signal has variable dutycycle, i.e. opening time can be about letter Number cycle and change.This change of dutycycle has efficiently controlled the quantity of power transmitted by power converter level A3.

Power converter level B 5 injects a current into supply of electric power 6.Thus, topology utilizes some devices to control from electric capacity C_dc4 electric currents flowing into main line 6.Circuit topology can be voltage source converter or current source converter.

Fig. 2 shows the example of power adjustment unit, can be by the control system of Fig. 1 in wherein.In fig. 2, Q1- Q4, D1-D4 and transformator define voltage amplifier；Q9, D5, D6 and Lout perform rectification；And Q5-Q6 constitutes " stretching, extension " Level.The control of the transistor that controller A (in Fig. 1 7) can be connected in power converter level A 21 connect (such as gate pole or Base stage), to control from the DC energy 20 through-put power.The input of this grade is connected to the DC energy, and the output of this grade is connected to DC chain Connect electric capacity 22.The storage of this electric capacity is from the energy of the DC energy, for delivery to main linely connected power sup ply 24.Controller A can configure with from The DC energy extracts the power of substantial constant, and does not consider C_dcOn DC link voltage V_DC。

The control of the transistor that controller B (in Fig. 1 8) can be connected in power converter level B 23 connects, with control System transfers power to main linely connected power sup ply.The input of this grade is connected to DC and links electric capacity, and the output of this grade is connected to main linely connected power sup ply. Controller B can configure substantially sinusoidal electric current is injected main linely connected power sup ply, and does not consider C_dcOn DC link voltage V_dc。

Electric capacity C_dc4 as with from the energy buffer being input to output.Via power stage A 3, energy is provided to electric capacity In, from electric capacity, extract energy via power stage B 5 simultaneously.System provides control method, its balance average energy transmission, and Allow by by AC power inject main line 6 and with electric capacity C_dcVoltage pulsation produced by the average D/C voltage superposition of 4, such as institute in Fig. 3 Show.Accompanying drawing shows the average voltage of 475V, and the 100Hz fluctuation of peak amplitude 30V.Duplication amplitude depends on from input (in Fig. 1 2) transmission is to the quantity of power exporting 6.The amplitude of vibration can be 100Hz or 120Hz, depends on line voltage frequency (respectively 50Hz or 60Hz).

Two pieces synchronize and independent control module control system 1: control module A 7 directly controls power stage A 3, and controls Module B 8 directly controls power stage B 5.

Control module A7 has structure as shown in Figure 4.It includes adder 31, negative proportional gain 32, PWM generator 33, system equipment (plant) 34 and feedback oscillator 35.Voltage on this control module regulation DC source 2.This voltage V_inBy gain k₁35 measure and regulation.Subsequently, adder 31 is used to deduct voltage reference value V_ref.Subsequently by this error (v_ref-k₁v_in) be multiplied by- k₂The factor.The signal produced becomes to bear ratio with error.Thus, positive error produces the contrary minimizing driving signal.This is driven Dynamic signal inputs to PWM generator 33, and it can be microcontroller or PWM integrated circuit.This module produces digit pulse, its Drive the transistor of power stage A 3 being equivalent to system equipment 34 successively.

Control DC source 2 voltage directly to control to transmit the power by power stage A 3, such as reference photovoltaic plate array institute in Fig. 5 Show.

Control module B 8 has structure as shown in Figure 6.It has adder 31, has the sampling holding of cycle T (SH) module 42, proportional derivative compensation device 43, system equipment 44, low pass filter (LFP) feedback module 45.This control module Regulation electric capacity C_dcAverage voltage on 4.Due to voltage V_DCComprise constant voltage and and the summation of fluctuation sinusoidal part, use LPF Module 45 regulates size and the trap signal of signal.This generates constant voltage, use adder 41 by itself and reference value ratio Relatively v_{dc_ref}.Sampling is used to keep SH module 42 every T minute measurement error.The sampling error produced is sent to PD compensate Device 43, PD compensator 43 arranges the current amplitude injecting main line 6 via power stage B 5.This current reference amplitude is carried out every the T second I_refRenewal, it is the inverse of line voltage frequency.Thus, it can distinguish value for the line frequency of 50 or 60Hz 0.02 or 0.0167 second.This contributes to preventing electric current from injecting distortion.

Fig. 7 shows the embodiment of control module A and B.Two pieces of module independent operatings, but for simplicity, Share common microcontroller.This microcontroller perform as in Fig. 6 about the control strategy shown in module B.If additionally, input Source is the photovoltaic panel in modules A, and microcontroller can include some devices of maximum power point tracking, in order to produce such as Reference input voltage used in Fig. 4.Therefore, by input voltage and electric current and DC-link voltage via operational amplifier Or the setting of signal-adjusting module and be fed into microcontroller.

The simulation electronic device of the form of the operational amplifier as shown in Fig. 7 (51) and phase-shifted PWM control device is taked in use Part, implementing in Fig. 4 is the control shown in modules A.As it was previously stated, obtained by microcontroller via digital to analog converter (DAC) Input voltage reference value.In phase-shifted PWM control device, obtain proportional error, and this error and then produces for level A21 The pwm signal of transistor.

The enforcement of controller B 52 includes current transducer, the output electric current that its sensing is rectified.Use operational amplifier By this Signal Regulation to suitable voltage levvl, subsequently it is compared with reference current.By the algorithm shown in Fig. 6 in microcontroller Device produces reference current, and the numeric character produced is sent to DAC, in order to obtain simulation, transient current reference value.Base In periodically-varied current amplitude (cycle is equal to power transmission network voltage cycle), in order to avoid current distortion.Reference value and reality Comparative result between electric current, is buffered by D bistable multivibrator, and it drives the transistor Q9 in Fig. 2 successively.Crystal Pipe Q5-Q8 forms full-bridge, and it uses the analog circuit with power transmission network voltage synchronous to switch line frequency.At power transmission network voltage During positive half cycle, transistor Q5 and Q8 opens, and during the negative half cycle of power transmission network voltage, transistor Q6 and Q7 opens.

Fig. 8 shows output and the input power using aforementioned control.Clearly, instantaneous power output is to be superimposed to averagely On the occasion of upper sine.On the contrary, be constant on all stage of Input Online road voltage.Difference power defines electric capacity C_dcMiddle suction The energy received does not mates.This is revealed as the fluctuation on electric capacity effectively, as shown in Figure 3.

MPPT (maximum power point tracking) technology

We will describe a kind of method and system, for following the trail of the maximum power point of power generator and when coupleding to bear During load, extract ceiling capacity from this generator.In an embodiment, method/system includes two pieces of independent control modules.This is years old One module controls voltage amplifier stage, and it contacts with power generator.Power generator is preferably solar energy module.In embodiment In, the first control module does not act on the amount of transmission energy with regulation, but is only used as switch, it is allowed to energy Flow, Or stop energy to flow by amplifier stage from generator, and do not consider its amount.The output of voltage amplifier stage coupled to energy storage electricity Hold.Energy Flow thus depend in storage capacitor " space " amount (amount of the additional-energy that can store).Second controls mould Block is feedback control loop, and it makes storage capacitor contact with the output loading coupled.Second control module is by emptying storage Energy electric capacity, and adjust and will inject the quantity of power loaded.The most specially having plenty of, the second control module uses storage capacitor The level of the voltage pulsation on (storage electric capacity), to control the quantity of power obtained from power generator and the power injecting load Amount.In an embodiment, (recording) current value is not utilized.Thus, in an embodiment, maximum power point tracking uses two pieces completely Independent loop, and use the special variation characteristic curve of storage capacitor.

Some power generators, such as solar-energy photo-voltaic cell, have non-linear power characteristic curve, as shown in Figure 9. In the accompanying drawings, peak power can be labeled as acquisition at the point of X, which show maximum power point electric current Imp and voltage Vmp.Excellent Choosing, reaches and the operating point of the most energy of position generation.The method that we describe is to use to survey at the output of generator The voltage and current value obtained, to perform maximum power point tracking.Instead, the voltage wave during the method measures DC link Dynamic, and use the value recorded to follow the trail of maximum power point.

With reference to Figure 10 and 11, it is shown that according to an embodiment of the invention, solar energy PV power regulating system 1000 The input 1002 of one embodiment and the structure chart of output 1004 grades, it includes the DC input side for power adjustment unit MPPT control method.Thus, Figure 10 shows power generator 1010, such as one or polylith PV plate, and it is with substantial constant Amplification factor (its can less than or equal to or more than 1, this depend on such as DC input whether come from single PV plate or a string The plate connected) amplifier stage 1012 is fed.Power is provided to accumulator 1014 by successively, is coupled to place in an embodiment The storage capacitor of the DC link between the reverse level of input voltage amplifier stage and output voltage.Control module A1016 controls voltage Amplifier stage 1012, but in an embodiment, only by from the power-on of power generator or be cut to accumulator.In embodiment In, control module A does not provides variable gain control, and only includes the frequency oscillator fixed.Voltage reversal level 1018 has It coupled to the input of accumulator 1014, and the output of AC main line is provided to load 1020, such as, connect via power transmission network.Control Via sensing link 1022a (but in an embodiment, not sensing this electric current chained), module B1022 monitors that DC chains Voltage, and connect 1022b, c (in an embodiment connect 1022c be positioned in power adjustment unit) via sensing and monitor into The electric current entering load and the voltage loaded, and drive output signal 1022d is provided, it is used for controlling voltage reversal and (" stretches Exhibition ") level 1018, more particularly, for controlling to obtain from accumulator and enter via power transmission network offer the power of load.Door drives Dynamic signal 1022d sequentially controls the power converter switch (see also Fig. 2) of the reverse level of power 1018；This provides convenient Technology, for controlling the switching frequency of this grade.

In Fig. 10, control module A is used as power switch, it is allowed to power flow to voltage amplifier stage from power generator (or on/off or access effectively/pick out voltage amplifier stage).Control module A can also be set with at overvoltage and electricity The power from power generator is closed when pressure is not enough.

Voltage amplifier stage can have fixing amplification ratio, or the optional ratio that maybe can multiplex, the most permissible Thered is provided by wall plug transformer.Voltage amplifier stage can include half-bridge, full-bridge, push-pull type or similar voltage reversal level.This Reversely level can include semiconductor switching device, such as MOSFET.Voltage reversal level is coupled to transformator, and its amplification ratio is produced Required voltage in raw DC link storage capacitor, such as 400 voltage magnitudes.The output of transformator coupled to rectification stage.Can Inductance is included between storage capacitor to link at rectifier bridge and DC.

According to input voltage, voltage amplifier stage 1012 can provide × 5 to × 20 in the range of amplification, such as～35 The DC input voltage of volt is about × 12, it is provided that the DC link voltage of about 420 volts.

Figure 12 shows the more detailed circuit diagram of the example input stage 1002 implementing our described method.Power generator Can be solar energy module or one group of solar energy module.In this example, voltage amplifier stage includes half-bridge, and it includes that two are successively Row switch (MOSFET) Q1 and Q2, and two block series electric capacity C1 and C2, and transformator TX1.The rectification being constituted by a diode Device electric bridge 1013 coupled to the output of transformator.Rectifier bridge self coupled to DC and links electric capacity via filter inductance Ld Cd.Control module in Figure 12 creates constant dutycycle pwm signal, and thus modulation is not carried out.If Cd is complete , as voltage thereon limits, it exports equal to or more than the rectification from secondary transformer, then even if Q1 and Q2 is even Continuous opening and closing, do not have power to flow into Cd.Thus, control module A does not regulates the quantity of power extracted from generator.

Figure 13 shows the more detailed circuit diagram of the example output stage 1004 implementing our described method.With reference to Figure 13, Control module B measures the voltage pulsation in DC link, and it is for regulating the quantity of power obtained from power generator, and thus The quantity of power of load is injected in regulation.Preferably load is general-purpose power transmission network.Power transmission network load in the case of, controller B via Calibrate circuit (the possible divider circuit of R3 and R4) and measure the peak value on DC link electric capacity and valley point voltage.Use peak The scaled value of threshold voltage Vp and valley point voltage Vt is to calculate the flowing quantity of power (as described below) by electric capacity.In an embodiment, Voltage sensing is connected to control module B via commutator.

Energy storage and DC link capacitance

Owing to the AC characteristic being transmitted into the energy of power transmission network and the current-voltage of power that produced by solar energy module are special Levy curve, if peak power will be obtained from solar energy module, then energy accumulator is necessary in PV transducer.At me Preferably in design, energy accumulator is the representative of DC link storage capacitor.The quantity of power being transmitted into power transmission network relates to electric capacity In energy change, and thus relate to the voltage pulsation on electric capacity.Store the energy in one advantage of enforcement that DC chains, It is to allow on electric capacity, have bigger fluctuation.Formula 1 shows the pass on energy change, capacitance and electric capacity between voltage System:

$U_R=\frac{1}{2}{C}_{\mathrm{dc}}(V_P^2-V_T^2)---\left(1\right)$

Wherein V_PIt is capacitive peak voltage, and V_TIt it is electric capacity valley point voltage.The power transmitted is energy change per second. Figure 14 shows the fluctuation (sinusoidal fluctuation) on DC link electric capacity.

Thus module B by with reference to (according to) DC link voltage fluctuates and regulates the magnitude of current of injection, and be automatically obtained MPPT。

But, the MPPT tracer technique that we have been described above is not limited in the environment of power adjustment unit operation, its Allow the AC fluctuation degree (and controlling based on it) chained at DC at leisure.Thus may help, this technology is being described Described in detail after the operation of embodiment.

Consider by photo-voltaic power supply, DC link current I_dWith voltage V_dAnd enter the output electric current I of power transmission network main line_gridWith Voltage V_gridInput current I and voltage V to transducer are provided.Due to V_gridApproximately constant, is just injecting the power of power transmission network main line Ratio is in I_grid.Similarly, under lossless case, input power I V=I_d·V_d, thus I_d·V_dOn photovoltaic IV characteristic curve Determine the point of System Operation.In broad terms, system sensing V_dOn fluctuation, it is logical to flowing in an embodiment (as mentioned above) Cross the measured value of the power of DC link.More particularly, system controls output " stretching, extension " level (such as compensated stage transducer), with maximum Change DC link voltage/storage capacitor, and thus also maximize the power injecting AC main line.(those skilled in the art will realize Arrive, the V on himself_dDo not there is provided the good measured value that DC is chained power).

In a preferred embodiment, control module 1022 produces the semisinusoidal template voltage (width with power transmission network homophase Degree changes between 0 and 3.3 volt), compare for (rectification) version with the load current 1022b sensed. The load voltage 1022c sensed is only used for determining the phase place of AC main line.Chain (via line according at storage capacitor/AC Road 1022a) fluctuating level that senses, and adjust the amplitude of template.If template amplitude is more than sensing power transmission network electric current Amplitude, then conversion frequency increases more power is injected power transmission network, and vice versa.Thus, in the broadest sense, according to DC chain Connect fluctuation and adjust the amplitude of template, and control to export electric current with matching template amplitude.

With reference now to Figure 15, it illustrates example and control program, for control module B1022.Figure 15 is example；This area Skilled artisan will appreciate that and can carry out many changes.

Assume program with the startup of transducer for starting, the amplitude that first program initializes template signal is low to Arbitrary Relative Value, on 0-0.3 volt numerical range be the most previously 0.5 volt (step S1500).Refer again to Fig. 9, in this point On, the output voltage from photovoltaic panel is in maximum, and exports electric current and be substantially zero；The fluctuating level that DC chains also base Originally it is zero.

This program determines the phase place of AC power transmission network rail voltage S1502, and makes semisinusoidal template and power transmission network synchronization. Subsequently, this program sensing power transmission network electric current S1504, such as by measuring the voltage on current sensing resistor；On startup, this will It is approximately zero.Program determines the error value E of difference carried out self-template and sensed between power transmission network electric current S1506 subsequently, its During startup, (continuation previous cases) will be 0.5.Program determines the conversion speed of voltage reversal level 1018 based on this error subsequently, If in an example E be on the occasion of; increase conversion speed, if E is negative value, reduce conversion speed.Thus at this example In, on startup, template amplitude is more than the amplitude of the power transmission network electric current sensed, thus increases conversion speed.Which increase Inject the electric current (and thus power) of AC power transmission network main line, thus the fluctuation voltage that DC chains also increases.

In step S1510, the pulsating volage that this program test DC chains, and in step S1512, adjust based on this measured value Mould preparation plate amplitude, the especially increasing degree when pulsating volage increases, and vice versa.Program returns step S1504 subsequently, with Sensing injects the electric current of AC main line again.Thus, such as, if error is to increase on the occasion of, template amplitude, thus it is again More than having been injected into the amplitude sensing electric current of power transmission network, and thus the conversion speed of voltage reversal level increase again.So And, if formerly changing reduction, also reduce recorded pulsating volage (its sense obtain from photovoltaic panel voltage), drop subsequently Low template amplitude and thus the conversion speed of reduction voltage reversal level.So, technical operations are controlled anti-to control output voltage To level, thus photovoltaic panel is maintained essentially at its peak power output point.

We have described the power adjustment unit with the MPPT for photovoltaic panel, wherein power injects control module There is the sensing input coupleding to the storage capacitor that DC chains, and control the main line merit that DC to AC transducer controls to have been injected into Rate.Signal that control module of injecting power chains by measuring DC, its depend on the power that obtains from D/C voltage, and follow the trail of High-power, and thus without measuring the D/C voltage from PV plate and electric current.In an embodiment, signal is pulsating volage water Flat, and power injects the amplitude of control module controller AC electric current output, thus have been transferred to the quantity of power of power transmission network main line Depend on the amplitude of sinusoidal voltage composition on storage capacitor.

MPPT tracer technique preferably is implemented in the transducer of above-mentioned universal class.However, it is also possible to this technology is used for Other kinds of transducer, such as " four switch " transducer as described in our patent US7626834 (if especially its Front end has half-bridge or full-bridge DC booster stage (having transformator)).

Solar energy photovoltaic system constructs

We will describe the structure of photovoltaic power generation system in parallel according to an embodiment of the invention now.

With reference to Figure 16 a and 16b, which respectively show the embodiment of photovoltaic power generation system according to the present invention 1600、1650.In each case, two pieces of photovoltaic panel 1602,1604 are connected in parallel to include the solar energy of MPPT tracing system The DC input of transducer 1000, as previously mentioned.In Figure 16 a, it is connected in parallel outside transducer；In Figure 16 b, link in parallel Therein.

In an embodiment, transducer 1000 is microcolumn Gel immunlassay, such as, has less than 2KW, 1KW or the maximum of 600 watts Determine power.By increasing the value (but it still remains relatively small in an embodiment, e.g., less than 50 μ F) of storage capacitor, and Upgrading microcolumn Gel immunlassay is to operate from two pieces of obtainable power increased of (or polylith) plate.With reference to Fig. 2, in an embodiment, can To include reactor (choke) between the storage capacitor in linking at DC to DC transducer (power converter level A) and DC, with Buffering leaves the magnetizing current of transformator.These parts are also required to high-power, e.g., from about 2 amperes.

In the instance constructs of Figure 16, it is preferred that plate is essentially all coupling, the most substantially there is identical chi Very little/type/rated power.This contributes to realizing good MPPT tracking performance.Though it is shown that two blocks of plates being connected in parallel, but It is to increase more plate.

With reference now to Figure 17, it illustrates aforementioned MPPT follows the trail of how to operate two blocks of plates in parallel.The curve 1700 of Figure 17 Show the I-V curve of each of a pair parallel plate, and curve 1702 show when one block of plate shielded/make dirty time change Become.Maximum power point is shown as " X ", and it is seen that, when being in identical voltage, even if one block of plate is shielded, two boards is also Maximum power point can be lain substantially in.This is because when one block of plate is shielded, the change between two curves is relatively Little in order to produce sufficiently change between maximum power point, such as shown in curve 1704, then need to cover to heavens (thus such as, by-pass diode conducts electricity) and/or a part for plate break down, such as due to the fault of diode.

In order to help to understand the operation of embodiment, Figure 18 a shows the example internal structure of photovoltaic panel 1800, includes at this Three such as 24 diodes 1802,1804 and 1806 of string, often string have oneself by-pass diode 1802a, 1804a and 1806a.In string, any p-n junction of diode each produces voltage, and it may generally be the order of magnitude of 0.5 volt.

Figure 18 b shows have series coupled plate 1602,1606 and 1604, the power generation system of 1608 being connected in parallel 1850.It is effective, but different from plate the most in parallel, if one block of plate in the arranging of Figure 18 b is shielded, it produces electricity Pressure skew, because plate series connection (and in parallel) connects.When plate is not by Uniform Illumination, it reduce the effectiveness of MPPT.Thus In a preferred embodiment, the direct parallel level of plate is without middle series board.(it will be appreciated by persons skilled in the art that when being formed When being connected in parallel, the plate being connected in parallel can be connected directly between converter inside or outside).But, the one of the setting of Figure 18 b Individual potential advantage is to use it, and without inputting DC-to-DC transducer to increase DC input voltage, thus may be without Transformator.

Referring again to Figure 17, shown I-V curve increases along with temperature and declines i.e. along with temperature increases, the electricity of PV plate Pressure output declines, and power output also declines.For this reason, in some preferred embodiments, plate is set so that they are in operation In approximately or substantially go up and Temperature Matching.This helps avoid the notable voltage deviation (when measuring onboard) between plate, no Then it may affect MPPT tracking: in the broadest sense, in an embodiment, until bypass diode turns on, covers and just follows the trail of MPPT Produce impact, but between two boards, the marked difference of temperature will significantly more affect MPPT tracking.By shown in Figure 16 a The efficiency of the setting of type with wherein provide the setting of an independent transducer 1000 to compare every block of PV plate, and It is found that the order of magnitude of its difference as little as 1%.But, the structure of Figure 16 a provides the basic cost of every watt and saves, and also Reliability may be increased.

Although some currently preferred embodiments of the present invention uses MPPT as above, but still may be from being connected in parallel Obtaining other advantages in plate structure, plate wherein in parallel is connected to the common microcolumn Gel immunlassay with the MPPT of multi-form.This is outstanding It is because by increasing the amount of storage that DC chains, rather than significantly changes miscellaneous part, can substantially carry out micro-conversion The scaling of the rated power of device.Therefore, it is possible to use the microcolumn Gel immunlassay of type the most as shown in Figure 2, have in its front end MPPT follows the trail of, but still provides interesting advantage in the cost savings of every watt.

The technology that we have been described above applies also for producing three-phase AC power transmission network main supply, such as, use the PV of Figure 19 Power generation system 1900.In the present arrangement, transducer 1000 ' is the revision of transducer 1000, wherein for each phase Position is respectively provided with three DC-extremely-AC transducer 1018a, b, c.The value of storage capacitor 1014 can be reduced, because energy is stored Demand less (at least one phase place output all the time due to whenever).Still can use for sensing storage capacitor Upper fluctuation and use the peak value (i.e. half peak-to-peak) of fluctuation to control to have been injected into the formerly described technology of the power of AC main line, but It is the reduction of the amplitude of fluctuation voltage.

Mathematical, those skilled in the art will know other effective alternatives many.It should be appreciated that The present invention is not limited to described embodiment, but includes being positioned in the range of appended claims, for people in the art Modification obvious for Yuan.

Claims (18)

1. photovoltaic power produces a system, and this system includes:

At least two pieces of photovoltaic panel, each piece of photovoltaic panel has the output of DC power；

Power adjustment unit, it has the input of DC power and AC main supply exports, and is used for providing AC main linely connected power sup ply；

The described DC power output-parallel of wherein said at least two pieces of photovoltaic panel is connected to the described DC of described power adjustment unit Power inputs；

Wherein said power adjustment unit includes that input coupled to the input of described DC power, and output coupled to described power and adjusts DC to the DC transducer of DC link of joint unit, input coupled to described DC link, and output coupled to described AC main line electricity Source output DC to AC transducer and coupled to described DC link energy-storage capacitor；

Wherein said power adjustment unit is configured to perform maximum in response to the power level flowing into the input of described DC power Power points is followed the trail of, and wherein at described DC link, sensing flows into the described power level of described DC power input；

Wherein said power adjustment unit includes controller, and the coupling of this controller is to control described DC to AC transducer to perform High-power point tracking；And

Wherein said controller has sensing input, and the input of this sensing coupled to described energy-storage capacitor, with in response to flowing into institute State power adjustment unit described DC power input power level and at described energy-storage capacitor sensing signal, wherein said Controller is configured to by response to the described DC merit flowing into described power adjustment unit sensed at described DC link The described power level of rate input, controls described DC to AC transducer and injects the power of described AC main supply with control, and hold The described maximum power point tracking of row；And

Wherein said at least two pieces of photovoltaic panel are directly connected in parallel to the described DC power input of described power adjustment unit, and Wherein said at least two pieces of photovoltaic panel are connected in the outside or inside of described power adjustment unit in parallel；

Voltage on wherein said energy-storage capacitor has the sinusoidal voltage composition of described AC main line doubled frequency, wherein said control The value of sinusoidal voltage composition described in the described sensing input sensing of device processed, and the configuration of wherein said controller is to control to provide extremely The amplitude of the AC electric current of described AC main supply output, thus the quantity of power that transmission exports to described AC main supply depends on institute State the amplitude of described sinusoidal voltage composition on energy-storage capacitor；

Wherein said AC main supply is three-phase output, and each phase of wherein said power adjustment unit all includes a DC To AC transducer, each described DC to AC transducer is all coupled to public described DC link.

2. photovoltaic power as claimed in claim 1 produces system, it is characterised in that wherein said DC to AC transducer includes coupling Close the DC input of described energy-storage capacitor；

Wherein said controller is configured to by adjusting in response to the described power of the inflow sensed at described energy-storage capacitor The described power level of the described DC power input of joint unit, controls described DC to AC transducer to control to inject described AC main line The power of power supply, and perform described maximum power point tracking.

Photovoltaic power the most according to claim 2 produces system, and the described sensing input of wherein said controller coupled to Described DC links.

4. producing system according to the photovoltaic power described in any one in claim 1-3, wherein said controller is configured to Control the described amplitude of the described AC electric current provided to the output of described AC main supply, substantially to maximize described sinusoidal voltage The described value of composition.

5. producing system according to the photovoltaic power described in claim 1, wherein said controller is arranged to control described DC To AC transducer to follow the trail of the maximum power point of D/C power, and without directly measuring the D/C voltage provided from described D/C power or DC Electric current.

6. according to described in claim 1 photovoltaic power produce system, wherein said power adjustment unit for described at least Two pieces of photovoltaic panel have single, public maximum power point tracking system.

7. producing system according to the photovoltaic power described in claim 1, wherein said energy-storage capacitor is non-electrolytic capacitor.

8. photovoltaic power produces a system, and this system includes:

At least two pieces of photovoltaic panel, every piece of photovoltaic panel has the output of DC power；

Power adjustment unit, this power adjustment unit has the input of DC power and for providing the AC main line electricity of AC main supply Source exports；

The described DC power output of wherein said at least two pieces of photovoltaic panel is connected in parallel to each other, and described at least two pieces of photovoltaic panel is described DC power output-parallel is connected to the described DC power input of described power adjustment unit；

Wherein said power adjustment unit includes DC to AC transducer, and is positioned at the described DC power of described power adjustment unit Inputting the DC link between the input of described DC to AC transducer, wherein said DC to AC transducer has and coupled to described AC The output of main supply output, and wherein said power adjustment unit also includes coupleding to the storage capacitor of described DC link Device；

Wherein said energy-storage capacitor is non-electrolytic capacitor；And

Wherein said power adjustment unit includes controller, and configuration is with in response to the power water flowing into the input of described DC power Flat, and perform maximum power point tracking；And

Wherein said controller has sensing input, and the input of this sensing coupled to described energy-storage capacitor, with in response to flowing into institute State power adjustment unit described DC power input power level and at described energy-storage capacitor sensing signal, wherein said Controller is configured to by response to the described DC merit flowing into described power adjustment unit sensed at described DC link The described power level of rate input, controls described DC to AC transducer and injects the power of described AC main supply with control, and hold The described maximum power point tracking of row；And

Wherein said at least two pieces of photovoltaic panel are directly connected in parallel to the described DC power input of described power adjustment unit, and Wherein said at least two pieces of photovoltaic panel are connected in the outside or inside of described power adjustment unit in parallel；

Voltage on wherein said energy-storage capacitor has the sinusoidal voltage composition of described AC main supply doubled frequency, Qi Zhongsuo State the value of sinusoidal voltage composition described in the described sensing input sensing of controller, and the configuration of wherein said controller is to control to carry It is supplied to the amplitude of the AC electric current of described AC main supply output, thus the quantity of power that transmission exports to described AC main supply depends on The amplitude of described sinusoidal voltage composition on described energy-storage capacitor；

Wherein said AC main supply is three-phase output, and each phase of wherein said power adjustment unit all includes a DC To AC transducer, each described DC to AC transducer is all coupled to public described DC link.

9. the photovoltaic power as described in claim 1-2, any one in 8 produces system, it is characterised in that described at least two Block photovoltaic panel is mated substantially, and has essentially identical sizes/types/rated power.

10. the photovoltaic power as described in claim 1-2, any one in 8 produces system, it is characterised in that described controller The level of the voltage pulsation being configured to only use on the energy-storage capacitor being coupled to described DC link by sensing input, and nothing The current value that described DC chains need to be used, do with being injected into described AC with the quantity of power controlled from the output of described DC power is extracted The quantity of power of line power supply.

11. photovoltaic powers according to claim 8 produce system, and the input of wherein said sensing coupled to described storage capacitor Device, in response to flow into described power adjustment unit described DC power input power level and at described energy-storage capacitor Place's sensing signal, and described controller also has control output, to control described DC to AC transducer, so that providing to institute The AC current amplitude stating the output of AC main supply depends on the amplitude of described sinusoidal voltage composition on described energy-storage capacitor.

12. photovoltaic powers according to claim 8 produce system, are arranged to control offer defeated to described AC main supply The AC current amplitude gone out, thus transmission to the quantity of power that described AC main supply exports depends on DC electricity on described energy-storage capacitor The peak amplitude of the fluctuation sine component of pressure, with in response to the described power adjustment unit of injection sensed at described DC link Described DC power input power described level control inject described AC main supply power.

13. produce system according to the photovoltaic power described in claim 1,2 or 8, and wherein said power adjustment unit also includes DC-is to-DC transducer, and its input coupled to the input of described DC power, and its output coupled to described DC link.

14. produce system, each positive and negative end of wherein said photovoltaic panel according to the photovoltaic power described in claim 1,2 or 8 End is connected to each other.

15. produce system according to the photovoltaic power described in claim 1,2 or 8, and wherein said photovoltaic panel includes the string of parallel connection Yoke plate, wherein said photovoltaic panel is connected in parallel with each other via one or more middle series board.

16. 1 kinds of methods producing AC main supply from polylith photovoltaic panel, the method includes:

DC power output-parallel from described photovoltaic panel is connected to the DC power input of power adjustment unit；

Using described power adjustment unit to change the circulation of DC power into described AC main supply, wherein said conversion includes DC merit The inlet flow of rate output is converted in the middle of the DC power at the DC link of the described power adjustment unit coupleding to energy-storage capacitor Stream, and the described intermediate flow of DC power is converted into rail current；And

Follow the trail of the substantially maximum power points of the public inlet flow of DC power output；

Wherein said tracking includes the described intermediate flow of sensing DC power, and controls the institute of DC power in response to described sensing State centre and flow to the described conversion of described AC main supply；

Two pieces of photovoltaic panel of at least a part of which are directly connected in parallel to the described DC power of described power adjustment unit and input, and wherein Described at least two pieces of photovoltaic panel are connected in the outside or inside of described power adjustment unit in parallel；

Voltage on wherein said energy-storage capacitor has the sinusoidal voltage composition of described AC main supply doubled frequency, wherein controls The value of sinusoidal voltage composition described in the sensing input sensing of device processed, and the configuration of wherein said controller is to control to provide to described The amplitude of the AC electric current of AC main supply output, thus the quantity of power that transmission exports to described AC main supply depends on described storage The amplitude of described sinusoidal voltage composition on energy capacitor；

Wherein said AC main supply is three-phase output, and each phase of wherein said power adjustment unit all includes a DC To AC transducer, each described DC to AC transducer is all coupled to public described DC link.

17. according to the method described in claim 16, and wherein the described centre of DC power flow to the institute of described AC main supply State conversion, increase the input voltage from described parallel photovoltaic plate including via the most fixing amplification factor.

18. 1 kinds of systems being used for producing AC main supply from polylith photovoltaic panel, this system includes:

Input to provide for the DC power output-parallel from described photovoltaic panel is connected to the DC power of power adjustment unit The device of the public stream of DC power；

For using described power adjustment unit to change the circulation of DC power into the device of described AC main supply, wherein said conversion The DC merit chained including the DC that the inlet flow of DC power is converted into the described power adjustment unit coupleding to energy-storage capacitor Rate intermediate flow；

For the described intermediate flow of DC power being converted into the device of described AC main supply；And

For following the trail of the device of the maximum power point of the public inlet flow of substantially DC power；

Described tracking includes the described intermediate flow of sensing DC power, and control in response to described sensing DC power described in Between flow to the described conversion of described AC main supply；

Two pieces of photovoltaic panel of at least a part of which are directly connected in parallel to the described DC power of described power adjustment unit and input, and wherein Described at least two pieces of photovoltaic panel are connected in the outside or inside of described power adjustment unit in parallel；

Voltage on wherein said energy-storage capacitor has the sinusoidal voltage composition of described AC main supply doubled frequency, wherein controls The value of sinusoidal voltage composition described in the sensing input sensing of device processed, and the configuration of wherein said controller is to control to provide to described The amplitude of the AC electric current of AC main supply output, thus the quantity of power that transmission exports to described AC main supply depends on described storage The amplitude of described sinusoidal voltage composition on energy capacitor；

Wherein said AC main supply is three-phase output, and each phase of wherein said power adjustment unit all includes a DC To AC transducer, each described DC to AC transducer is all coupled to public described DC link.