CN103731095B - The startup of solar plant - Google Patents

Abstract

The invention provides a kind of method for one or more start-up parameter of solar generator system is optimized and solar generator system.Described solar generator system includes solar array and for the changer converting the power obtained from described plate array.Described method includes: measure the output voltage of described plate array；By described output voltage and startup voltage (V_dc) compare；When the described output voltage of described plate array exceedes described startup voltage (V_dc) time, start described solar generator system；After starting in the morning, measure the power obtained from described solar array；The power obtained is compared with known limits value, and based on power relatively changed one or more start-up parameter.

Description

The startup of solar plant

Technical field

The present invention relates to photovoltaic generation, relate more specifically to the startup of photovoltaic generating system.

Background technology

Photovoltaic (PV) electricity generation system includes one or more photovoltaic panel constituting plate array.This plate Array and is used for the power of generation is supplied to electrical network from the energy capture of these plates with for optimization Or the power electronic equipment of energy storing device connects.This power electronic equipment includes for amendment from plate The voltage of array acquisition and/or one or more transducer-level of electric current.Although the electricity in PV system Power electronic equipment generally comprises other converter topology structure in addition to inverter, but generally by these Equipment is referred to as solar inverter or PV inverter.

Solar plant or photovoltaic generating system work under changing environmental conditions as opposed.Environmental aspect is with season Joint and weather and change.This causes the standard for setting the parameter for optimum startup situation non-constant The fact.If too early start PV electromotor in the morning, then PV electromotor can not produce enough merits Rate and general shut down, in order to be again started up after a while.Such unnecessary startup and shutdown abrasion electromotor The parts of system.On the other hand, if starter-generator system too late, then some energy will be lost, That is, all possible energy from solar panels is not all fed to electrical network.

It is known that according to changing condition to being used as to be connected to the startup standard of the changer of solar panel system Parameter be optimized.The generic instance of startup standard is the time of the voltage from plate array and startup Postpone.According to these standards, morning, start-up course included: monitor the open-circuit voltage from plate array, And when this voltage exceedes the set limit, after the time period set by time delay expires Start solar inverter.In known systems, according to these parameters of current status manual correction.? During the trail run of solar plant and work, need volume for starting the manually setting of parameter of standard Outer work.

Manually optimizing of parameter also causes non-optimal situation because of the situation of change.Such as, when PV plate When being coated with dust, electricity generation system can not start with the initial standard set for clean board.Work as plate Or it can occur same problem when connecting faulty.Therefore, when utilize new plate replace old plate time or work as When plate is keeped in repair, it is no longer optimum for starting the standard set.

It is also known that by using external irradiation or temperature sensor to carry out optimal startup parameter.But, this The external sensor of sample adds complexity and the cost of system.Additionally, these external sensors can not Consider the change occurred in PV plate.Such change such as occurs when plate wears or be dirty.

Summary of the invention

It is an object of the invention to provide a kind of in order to solution to the problems described above with for implementing the party The system of method.The purpose of the present invention is realized by the method and system described in independent claims.? Dependent claims discloses the preferred embodiment of the present invention.

The present invention is based on following design: based on after starting from plate array obtain measured by meritorious Power carrys out optimal startup parameter.By measured active power with successfully start up required known preferred Power compares, and relatively changes start-up parameter based on this.

The parameter of startup standard is automatically changed so that starts and is applicable to possible changing condition.This The topology of the change of the changing condition of sample for example, PV plate or amount and/or the atmospheric condition of change.Profit By this method and system, the operator of solar generator system need not system trail run or Parameter is manually changed during work.

Accompanying drawing explanation

Below will be by preferred embodiment and the present invention is described in detail with reference to the accompanying drawings, at accompanying drawing In:

Fig. 1 shows the flow chart of embodiments of the present invention,

Fig. 2 shows the flow chart of the embodiment reducing startup standard,

Fig. 3 shows the flow chart of the embodiment increasing startup standard, and

Fig. 4 shows the simplification structure of photovoltaic generating system.

Detailed description of the invention

When solar array receives the irradiation from the sun after night, the open-circuit voltage of plate is opened Begin to rise.When open-circuit voltage exceedes and starts, for morning, the ultimate value set, after a time delay The operation of starter-generator system (i.e. one or more changer).Postpone T_startLength and Voltage limit V_dcFor starting the parameter set for morning.In the present invention, when the change starting system During parallel operation, determine actual power P obtained from plate array_ac,k.Preferably, according to from plate array The measured value of electric current and voltage determines power.Need not come really according to electric current and the voltage directly from plate Determine power.Power can be determined according to the electric current measured in the converter and voltage.Replace electric current and Both voltage is measured value, and one of these values can also be by a certain control circuit in transformer configuration The reference value exported.Additionally, when output voltage has fixed value, it is also possible to according to by changer The electric current of system output determines power.

When determining system power P after startup moment_ac,kTime, by itself and ultimate value P_ac,opt Compare.This ultimate value represents for keeping the optimum required for power converter system reliability service Start power level.The changer system of PV electricity generation system needs the power for system operation.This Mean that a part of power obtained from plate array is used by power converter system, and a part of power It is dissipated in systems as power attenuation.Somewhat know that these are lost, in order to can grasp in system For system estimation ultimate value P before work_ac,opt.This limit is must be over from the power of plate array output Value, in order to the operation of changer system and the output of power become possibility.This ultimate value can comprise peace Full allowance so that the slightly below value of this limit be enough to operational transformation device system.

If actual power P of system_ac,kClose to ultimate value P_ac,opt, it is determined that need not change for The start-up parameter that start in the morning.But, if actual power P_ac,kCertain higher or lower than ultimate value Amount, then make a change start-up parameter.In the embodiment of the method, determine certain delayed change Change the limit, and when actual power is outside the scope of these limit, this startup is not optimum. In embodiments, thus check whether and meet following formula:

P_ac,opt–P_h<=P_ac,k<=P_ac,opt+P_h (1)

Wherein, P_hHysteresis limits for definition.As previously discussed, if meeting the condition of (1), The most do not change start-up parameter.

If actual power P_ac,kHysteresis limits (that is, P is added higher than ultimate value_ac,k>P_ac,opt+P_h), The power exported the most on startup exceedes required minimum power, and can more early start power plant. This relatively early startup is performed by changing one or more parameter in start-up parameter.

As it has been described above, startup standard includes starting voltage V_dcWith time delay T_start.The present invention's In embodiment, when actual power P_ac,kWhen adding hysteresis limits higher than ultimate value, determine startup voltage Whether start voltage V higher than minimum_dc,min.The minimum voltage that starts obtains from plate, can successfully open Dynamic magnitude of voltage.If it is determined that startup voltage start voltage, then fall low start voltage higher than minimum Value.Preferably, by deducting fixed voltage value V from previous startup voltage_stepPerform startup Voltage V_dcReduction.In the embodiment of the method, magnitude of voltage V_stepCan also be for passing through function The variable calculated.This function may be relevant with such as historical data, i.e. causes opening when starting continuously Bigger step-size is selected when galvanic electricity pressure drop is low.This function is also possible to be had with the currency starting voltage Close, i.e. select less step-size when starting voltage close to minimum startup voltage.

If starting voltage not higher than minimum to start voltage, the most do not change startup voltage.Therefore, start Voltage is endowed this minimum and starts the value of voltage.

In another embodiment of the present invention, one or more start-up parameter to be changed is the time Postpone T_startValue.Actual power P determined by when_ac,kHigher than ultimate value and hysteresis limits and time, Unless time delay T_startValue be in minimum level, otherwise come relatively early by reducing this time delay Ground carries out the startup of PV electricity generation system.Therefore, in the method, if it is determined that time delay T_start Value higher than minimum acceptable value T_start,min, then parameter T is reduced_startValue.As combined startup voltage, Preferably, by from the T used_startValue in deduct constant T_stepWhen progressively reducing startup Between postpone.If T_startNot higher than T_start,minValue, then by T_start,minValue give parameter T_start。 According to another embodiment, according to may be with historical data (that is, previous morning starts) or T_start Currency and minimum acceptable value T_start,minBetween the relevant function of difference, changing the startup time prolongs Late.

According to embodiment, when starting the power scope higher than the optimal value of power (that is, higher than the limit Value with hysteresis limits and) time, according to above procedure change the startup time and startup both voltage.

If actual power P_ac,kLess than ultimate value (that is, the P having deducted hysteresis limits from which_ac,k< P_ac,opt–P_h), then when starting, the power of output is insufficient and should change start-up parameter.Excellent Selection of land, sets hysteresis limits: in this approach as follows, even if slightly below should in actual power During scope, remain able to start changer system.When starting power less than this scope, it should be ensured that Increase for one or more in the parameter set by startup.

It is contrary for increasing the process of start-up parameter with the above-mentioned step for reducing parameter.According to Embodiment, when actual power P_ac,kDuring less than allowable range, check and start voltage V_dcThe lowest In starting the maximum V set by voltage_dc,max.If starting voltage to be less than this maximum, then increase Start greatly voltage.Preferably, by being currently up voltage increase steady state value V_stepIncrease startup Voltage.As reduced in the case of parameter, it is also possible to based on historical data or start the current of voltage Difference between value with the maximum starting voltage calculates and starts the value that voltage is added.

If starting voltage to be not less than maximum V_dc,max, then voltage V is started_dcObtain maximum voltage value V_dc,max。

According to another embodiment, by increasing time delay T_startIncrease in start-up parameter Individual or more start-up parameter.Therefore, according to embodiment, determine time delay T_startThe lowest Time delay T is started in maximum_start,max.If so, then the value of time delay is increased Big time step T_step.If time delay T_startBe not less than the maximum time delay that starts, then will be The value of big time delay gives time delay T_start.As above, for changing the time rank of time delay Jump T_stepValue be preferably constant, or it can be that utilization considers historical data or T_start Currency and the maximum of start delay between the variable that calculates of the function of allowance.

According to the embodiment of the present invention, when starting power less than optimal power, according to above procedure Change time delay and start both voltage.

By above-mentioned parameter (that is, time delay T determined for startup_startWith startup voltage V_dc) deposit Storage is in systems so that use these parameters in the startup in next morning.Additionally, according to enforcement Mode, the value of storage time delay and/or startup voltage is to gather historical data.These data are used for Determine that system becomes defective the most lentamente.Such as, if time delay T_startAnd startup Voltage V_dcIncrease to maximum limit or Rapid Variable Design at short notice, then system may experience fault. Therefore, it is possible to use the parameter of change generates alarm to attendant so that can lose completely in system System possible repair system is checked before effect.Similarly, the method for the present invention can be given covering The expression of snowy plate.

When solar plant is equipped with when including the system of method of the present invention, and the terminal use of power plant is not Start-up parameter must be set.Furthermore, it is not necessary that know the attribute of PV plate, this is because the method can be certainly Oneself adapts to.If some PV plates being added in system or replacing old PV plate, then start-up parameter To automatically adapt to and without any effort of staff.Similarly, wear when the plate of system and When the power of plate output is just slowly decreased, the method makes the output level that parameter adaptation changes. Additionally, the method and system are by the most faulty also to one group of plate array of observation or direct current (DC) fuse Change start-up parameter.

The method and system the most automatically observe the change of atmospheric condition in start-up parameter.These changes Situation includes the change of the rise angle of annual variations in temperature and the sun.Plate array temperature impact with Start the open-circuit voltage that compares of voltage limit, and the length of the rise angle of the sun and time delay has Close.Consider the two factor the most independently and automatically.The open-circuit voltage of plate array is relatively low At a temperature of higher.But, when plate being loaded (i.e. connection) to changer, if the irradiation to plate Inadequate, then voltage declines.Therefore, start-up parameter is contemplated that variations in temperature.In the present invention In, automatically consider temperature.Similarly, in the period that the sun rotates every year, the sun is annual spy Fix time and comparatively fast rise.The time delay used when starting changer system considers lifting speeds or liter Play angle.In embodiments of the present invention, time delay automatically adapts to so that examine in parameter Consider the rise time of the sun.

Such as, when shortening daytime, morning, temperature tended to reducing.The reduction of temperature increases opening of plate Road voltage.If not changing start-up parameter, then the voltage caused because of lower temperature increases makes changer system System is to cross the generation energetic start up of low amounts.Voltage is started, it is considered to because lower temperature causes by increasing The open-circuit voltage increased.

Similarly, when the rise time of the sun is elongated, it should extend and made when starting changer system Time delay so that the irradiation of the plate of system is sufficiently great to initiate changer system.

Below, Fig. 1, Fig. 2 and Fig. 3 of flow chart of embodiment it are shown in conjunction with to describe the present invention Operation.In FIG, when exceeding from the voltage of plate or reaching limit V set_dcAnd more Time T after overvoltage limit value_startTime at the expiration, start PV electricity generation system 1.Therefore, when from plate Voltage reach set limit V_dcTime, start intervalometer with computing relay T_start.In time delay Afterwards, start changer system, and determine the power P obtained from plate array_ac,k2。

After starting changer and determining power, also determine that whether this startup is to start 3 morning.Example As, this can realize by using real-time clock.If it is determined that this startup is not to start, then morning Start-up parameter is not made a change, and former state keeps V_dcAnd T_startValue 4.

If this startup is to start morning, it is determined that whether actually determined power is in optimized scope 5.As set forth above, it is possible to the power limit that the optimized scope starting power is defined as in hysteresis limits. Actual power upon start up within the range time, determine need not change start-up parameter 6.If opened Kinetic power the most within the range, then checks that whether this power is higher than optimized scope 7.Determined by if Actual power is higher than limited range, then reduce start-up parameter 8, and if this power is not higher than institute The scope limited, then increase start-up parameter 9, this is because have determined that this power is outside optimized scope. Show reduction the most in more detailed manner and increase start-up parameter (block 8 and block 9).

Fig. 2 shows the embodiment reducing start-up parameter, the i.e. block 8 of Fig. 1.When determining that power is high When optimized scope, reduce start-up parameter.In the process reducing parameter, check and start voltage V_dc Whether higher than for starting minima V that voltage sets_dc,min81.If starting voltage to be higher than lower limit, The value 82 of low start voltage then drops.In the embodiment of Fig. 2, by opening of using in time starting Galvanic electricity pressure deducts steady state value V_stepLow start voltage drops.Therefore, in starting next morning, Changer system is started with the relatively low virtual voltage of plate array.

If starting voltage V_dcNot higher than minimum starts voltage V_dc,min, then start voltage and receive minimum Start the value 83 of voltage.In other words, start voltage and can not be entered one already at actual lower limit Step reduces.

The reduction of the start-up parameter of Fig. 2 is it is disclosed that by start delay T_startWith minimum start delay T_start,minCompare 84.If the start delay used is more than minima, then start delay is made to subtract Little by 83.In the embodiment of Fig. 2, by from T_startCurrency in deduct constant T_stepSubtract Little start delay.If start delay T_startIt is not more than the minima postponed, then T_startObtain minimum The value 86 postponed.

Fig. 3 shows owing to startup power increases the embodiment party of start-up parameter 9 less than optimized scope Formula.In figure 3, the startup voltage V used is checked_dcWhether less than for starting what voltage set Upper limit V_dc,max91.If starting voltage to be less than the upper limit, then by by increment V_stepBe currently up Voltage V_dcPhase Calais increases this voltage 92, with obtain next morning start in use and should be total It is less than the startup voltage of open-circuit voltage.If starting voltage to be not less than the upper limit, then provide the upper limit V_dc,maxValue as start voltage V_dcValue.

The most in figure 3, by by start delay T_startMaximum of T with the time of startup_start,max Compare 94 and increase start delay when the value of the start delay used is less than maximum 95, increase start-up parameter.By by constant T_stepPerform with the currency phase Calais of time delay This increase.If the start delay used is not less than maximum, then maximum is set as that the time prolongs T late_start。

In the embodiment of Fig. 2 and Fig. 3, use constant V_stepAnd T_stepPerform to start voltage Increase with both time delays and reduction.As it has been described above, these values can also be variable.Additionally, Increasing and reduce the value used can be different from each other.It is to say, V_stepAnd T_stepCan be with not Increase parameter with value and reduce parameter.

The method of the present invention is preferably implemented in the changer system be connectable to solar array.Should Changer system also includes that the power feed for transformation into itself's device system in future is to AC network or DC The adapter of system.DC system can include DC memory unit or DC network.

Known there is the multiple changer being combined with solar energy and carrying out operating.The system of the present invention is not limited to The topology of this system, thus this system can include heterogeneous output and multiple transducer-level.Fig. 4 illustrates The simplification structure of the system of the present invention, wherein, solar array 41 is connected to transformer configuration 42.Transformer configuration 42 is additionally coupled to exchange (AC) electrical network 43.

In order to implement the method, this system includes arithmetic element and each for store used in operation Plant the memory unit of parameter.Additionally, this system includes the parts of the various comparisons for realizing the method.

Those skilled in that art are it is apparent that as technological progress, this inventive concept can be with respectively The mode of kind is implemented.The present invention and embodiment thereof are not limited to example described above, and can be in power Profit is changed in the range of requiring.

Claims (11)

1. one kind is used for being optimized one or more start-up parameter of solar generator system Method, wherein, described solar generator system includes solar array (41) and for right The power obtained from described plate array (41) carries out the changer (42) converted, and described method includes:

Measure the output voltage of described plate array,

By described output voltage and startup voltage (V_dc) compare,

When the described output voltage of described plate array exceedes described startup voltage (V_dc) time, start institute State solar generator system,

After starting in the morning, measure the power obtained from described solar array,

The power obtained is compared with known limits value, and

Based on power changed one or more start-up parameter, wherein described comparison

One of described start-up parameter is initiation voltage level, and described change one or more The step of start-up parameter comprises the following steps:

When the power obtained is higher than the upper limit, reduce described startup voltage, and

When the power obtained is less than lower limit, increase described startup voltage,

It is characterized in that,

The time delay used when one of described start-up parameter is by starting described electricity generation system, and change Become one or more start-up parameter comprise the following steps:

When the power obtained is higher than the described upper limit, reduce described time delay, and

When the power obtained is less than described lower limit, increase described time delay.

Method the most according to claim 1, wherein, described by the power obtained with known The step that ultimate value compares comprises the following steps:

The power obtained is compared with lower limit and the upper limit, and

When the power obtained is higher than the described upper limit or less than described lower limit, change one or more Multiple start-up parameter.

Method the most according to claim 1 and 2, wherein, by by voltage step (V_step) It is added or by the startup used in time being currently up with the voltage that starts used when being currently up Voltage (V_dcVoltage step (V is deducted in)_step), perform the increase or described of described startup voltage Start the reduction of voltage.

Method the most according to claim 3, wherein, described startup voltage (V_dc) have on Limit value (V_dc,max) and lower limit (V_dc,min), described higher limit and lower limit limit described startup electricity Pressure (V_dc) increase and reduction.

Method the most according to claim 4, wherein, described voltage step (V_step) it is constant Or variable, the value of described variable depends on and is currently up voltage and described higher limit (V_dc,max) or institute State lower limit (V_dc,minDifference between).

Method the most according to claim 1, wherein, by by time step (T_step) and work as The time delay used during front startup is added or by the time delay used in time being currently up In deduct time step (T_step), perform increase or the reduction of described time delay.

7. according to the method described in claim 1 or 6, wherein, described time delay has the upper limit Value (T_start,max) and lower limit (T_start,min), when described higher limit and described lower limit limit described Between postpone increase and reduction.

Method the most according to claim 7, wherein, described time step (V_step) it is constant Or variable, the value of described variable depends on current time and described higher limit (T_start,max) or described Lower limit (T_start,minDifference between).

9. according to the method described in aforementioned claim 1 or 2, wherein, described method also includes:

When one or more start-up parameter in described start-up parameter is in its ultimate value, generate alert Report.

10. according to the method described in aforementioned claim 1 or 2, wherein, described method also includes:

When one or more start-up parameter in described start-up parameter quickly increases, generate alarm.

11. 1 kinds of solar generator systems, wherein, described solar generator system includes the sun Can plate array and for changer that the power obtained from described plate array is converted, described system Including:

For measuring the parts of the output voltage of described plate array,

For by described output voltage and startup voltage (V_dc) parts that compare,

For exceeding described startup voltage (V at the described output voltage of described plate array_dc) time start The parts of described solar generator system,

For measuring the parts of the power obtained from described solar array after start-up,

For the parts that the power obtained is compared with known limits value, and

For based on the comparison of power being changed the parts of one or more start-up parameter, wherein

One of described start-up parameter is initiation voltage level, and described change one or more The parts of start-up parameter include:

When the power obtained is higher than the upper limit, reduce the parts of described startup voltage, and

When the power obtained is less than lower limit, increase the parts of described startup voltage,

It is characterized in that,

The time delay used when one of described start-up parameter is by starting described electricity generation system, and change The parts becoming one or more start-up parameter include:

When the power obtained is higher than the described upper limit, reduce the parts of described time delay, and

When the power obtained is less than described lower limit, increase the parts of described time delay.