CN116760107B - Method, system and storage medium for over-distribution load limiting of photovoltaic inverter - Google Patents
Method, system and storage medium for over-distribution load limiting of photovoltaic inverter Download PDFInfo
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- CN116760107B CN116760107B CN202311027014.8A CN202311027014A CN116760107B CN 116760107 B CN116760107 B CN 116760107B CN 202311027014 A CN202311027014 A CN 202311027014A CN 116760107 B CN116760107 B CN 116760107B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
- H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
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Abstract
The invention provides a method, a system and a storage medium for overdriving and limiting load of a photovoltaic inverter, and relates to the technical field of photovoltaic inverters; the method comprises the following steps: acquiring first parameter information when the photovoltaic inverter operates and second parameter information when a photovoltaic system connected with an input end of the photovoltaic inverter operates; when the first parameter information meets the load limiting condition, determining a PV voltage given value of the photovoltaic system according to the second parameter information; and controlling the photovoltaic system to output according to the PV voltage set value. According to the invention, based on the first parameter information when the photovoltaic inverter operates, whether the photovoltaic inverter needs to be limited in load or not is accurately judged, when the photovoltaic inverter meets the load limiting condition, the PV voltage given value of the photovoltaic system is determined according to the second parameter information of the photovoltaic system, so that the photovoltaic inverter is over-matched and limited in load by limiting the PV voltage, corresponding voltage lifting when the photovoltaic inverter is over-matched and limited in load is avoided, and stable operation of the photovoltaic inverter and equipment connected with the photovoltaic inverter is ensured.
Description
Technical Field
The invention relates to the technical field of photovoltaic inverters, in particular to a method, a system and a storage medium for overdriving load limitation of a photovoltaic inverter.
Background
In practical applications of the photovoltaic inverter, the configuration capacity of the photovoltaic panel is generally increased because the customer wants the grid-connected inverter to operate in the maximum output power state for a long time, so that an overdriving condition that the PV current exceeds the maximum allowable input current of the corresponding inverter is generated. Under the condition of over-distribution, if the output power of the inverter needs to be limited due to factors such as over-temperature, over-frequency or manual load reduction, the output power is generally realized by limiting the output current of the inverter, but the energy on the middle bus of the inverter is excessively high in a short time, the voltage of the middle bus of the inverter and the PV voltage are quickly raised, the PV voltage is limited to the right side of the maximum power point on the PV curve, and the equipment such as the photovoltaic inverter is in an easy-to-fail state.
Disclosure of Invention
The invention solves the problems that: how to avoid the voltage rise of the photovoltaic inverter during the overload limit.
In order to solve the above problems, the present invention provides an overdriving load limiting method of a photovoltaic inverter, comprising:
acquiring first parameter information when a photovoltaic inverter operates and second parameter information when a photovoltaic system connected with an input end of the photovoltaic inverter operates;
when the first parameter information meets a load limiting condition, determining a PV voltage given value of the photovoltaic system according to the second parameter information; the PV voltage given value is smaller than or equal to a second voltage corresponding to the maximum power point of the photovoltaic system;
and controlling the photovoltaic system to output according to the PV voltage set value.
Optionally, the second parameter information includes a first voltage and a first power of the output end of the photovoltaic system; the determining the given value of the PV voltage of the photovoltaic system according to the second parameter information comprises:
determining a first PV given voltage according to the first power and a preset limiting power; determining a second PV given voltage according to the first voltage and a preset bus voltage; taking the second voltage as a third PV given voltage;
the controlling the photovoltaic system to output according to the PV voltage set point comprises:
and taking the minimum value of the first PV given voltage, the second PV given voltage and the third PV given voltage as the PV voltage given value, and controlling the photovoltaic system to output according to the PV voltage given value.
Optionally, the determining the first PV given voltage according to the first power and the preset limiting power includes:
and determining the first PV given voltage through a corresponding PI regulator according to the difference value of the first power and the preset limiting power.
Optionally, the determining the second PV given voltage according to the first voltage and the preset bus voltage includes:
and determining the second PV given voltage through a corresponding PI regulator according to the difference value between the first voltage and the preset bus voltage.
Optionally, the second parameter information includes a maximum limit voltage of the bus corresponding to the output end of the photovoltaic system; when the first parameter information meets the load limiting condition, determining the PV voltage given value of the photovoltaic system according to the second parameter information comprises the following steps:
taking the minimum value of the second voltage and the maximum limiting voltage as a fourth PV given voltage;
and when the fourth PV given voltage does not meet the load limiting condition, taking the fourth PV given voltage as the PV voltage given value.
Optionally, after the minimum value of the second voltage and the maximum limiting voltage is taken as the fourth PV given voltage, when the first parameter information meets the load limiting condition, determining the PV voltage given value of the photovoltaic system according to the second parameter information further includes:
step 250, when the fourth PV set voltage meets the load limiting condition, reducing the fourth PV set voltage by a preset value to obtain a fifth PV set voltage;
step 260, when the fifth PV set voltage does not meet the load limiting condition, taking the fifth PV set voltage as the PV voltage set value; when the fifth PV set voltage meets the load limiting condition, assigning the fifth PV set voltage to the fourth PV set voltage in step 250, and looping through steps 250 to 260 until the finally obtained fifth PV set voltage does not meet the load limiting condition, and taking the finally obtained fifth PV set voltage as the PV voltage set value.
Optionally, when the first parameter information meets a load limiting condition, determining the given value of the PV voltage of the photovoltaic system according to the second parameter information includes:
judging whether the first parameter information meets the load limiting condition or not through a main DSP controller;
when the first parameter information meets the load limiting condition, a load limiting signal is sent to a slave DSP controller through the master DSP controller;
and when the load limiting signal is received from the DSP controller, determining the PV voltage given value of the photovoltaic system according to the second parameter information.
In order to solve the above problems, the present invention further provides an overdriving load limiting system of a photovoltaic inverter, including:
the acquisition unit is used for acquiring first parameter information when the photovoltaic inverter operates and second parameter information when the photovoltaic system connected with the input end of the photovoltaic inverter operates;
the operation unit is used for determining a PV voltage given value of the photovoltaic system according to the second parameter information when the first parameter information meets a load limiting condition; the PV voltage given value is smaller than or equal to a second voltage corresponding to the maximum power point of the photovoltaic system;
and the execution unit is used for controlling the photovoltaic system to output according to the PV voltage set value.
In order to solve the above problems, the present invention further provides a system for overdriving a photovoltaic inverter, which includes a computer readable storage medium storing a computer program and a processor, wherein the computer program is read and run by the processor to implement the method for overdriving a photovoltaic inverter.
In order to solve the above problems, the present invention further provides a computer readable storage medium, where a computer program is stored, and when the computer program is read and executed by a processor, the method for over-load limitation of the photovoltaic inverter is implemented.
Compared with the prior art, the invention has the following beneficial effects: according to the method, based on first parameter information when the photovoltaic inverter operates, whether the photovoltaic inverter needs to be limited or not is accurately judged, when the photovoltaic inverter meets the load limiting condition, a PV voltage given value smaller than or equal to a second voltage of the photovoltaic system is determined according to the second parameter information of the photovoltaic system, so that the photovoltaic inverter is over-matched and limited by limiting the PV voltage, corresponding voltage lifting of the photovoltaic inverter during over-matched and load limiting is avoided, a corresponding working point of the photovoltaic system can stay on a maximum power point or stay on the left side of the maximum power point on a PV curve according to the PV voltage given value when the photovoltaic system outputs the PV voltage, and the situation that equipment such as the photovoltaic inverter is in an easy-to-fail state due to overhigh busbar voltage, PV voltage and the like in the middle of the photovoltaic inverter when power is limited by directly limiting current is avoided, and stable operation of the photovoltaic inverter and equipment (such as the photovoltaic system, a power grid and a storage battery) connected with the photovoltaic inverter is ensured.
Drawings
Fig. 1 is a flowchart of a method for overdriving a photovoltaic inverter according to an embodiment of the present invention;
FIG. 2 is a sub-flowchart of step 200 in an embodiment of the present invention;
FIG. 3 is a sub-flowchart of step 200 in another embodiment of the present invention;
fig. 4 is a partial topology of an over-load limiting system for a photovoltaic inverter in an embodiment of the present invention.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein.
Referring to fig. 1, an embodiment of the present invention provides an overdriving load limiting method of a photovoltaic inverter, including the following steps:
step 100, acquiring first parameter information when a photovoltaic inverter operates and second parameter information when a photovoltaic system connected with an input end of the photovoltaic inverter operates;
step 200, when the first parameter information meets the load limiting condition, determining a PV voltage given value of the photovoltaic system according to the second parameter information; the set value of the PV voltage is smaller than or equal to a second voltage corresponding to the maximum power point of the photovoltaic system;
and 300, controlling the photovoltaic system to output according to the PV voltage set value.
The method is used for controlling the operation of the photovoltaic inverter, and is particularly used for realizing the load limiting when the photovoltaic inverter is in overdriving (namely, the PV current output by the photovoltaic system exceeds the maximum bearing current of the corresponding photovoltaic inverter). Specifically, first, through step 100, first parameter information of the photovoltaic inverter during operation and second parameter information of the photovoltaic system during operation are obtained (acquired and sampled), wherein the first parameter information includes output power, temperature information and the like of the photovoltaic inverter; the second parameter information comprises output voltage (PV voltage), output current (PV current), output power (PV power) of the photovoltaic system, output voltage (recorded as second voltage) corresponding to the maximum power point of the photovoltaic system and the like; in some embodiments, the output of the photovoltaic system is electrically connected with the input of the photovoltaic inverter such that the respective output parameter of the photovoltaic system is the input parameter of the corresponding photovoltaic inverter. Then, through step 200, it is determined whether the first parameter information obtained in step 100 meets the load limiting condition, that is, whether the photovoltaic inverter meets the load limiting requirement (that is, the photovoltaic inverter is required to reduce the output power due to some reasons, such as a change in illumination condition, a power grid requirement, a design requirement of the photovoltaic inverter itself, etc.); when the second parameter information meets the load limiting condition, if the temperature of the photovoltaic inverter in the second parameter information is too high, the output power exceeds the rated power of the photovoltaic inverter or the output power exceeds the input requirement of a power grid (or a storage battery) connected with the output end of the photovoltaic inverter, the photovoltaic inverter is determined to be subjected to load limiting, at the moment, the given value (which is smaller than or equal to the second voltage) of the PV voltage of the photovoltaic system is determined according to the second parameter information, and the like, so that the output voltage (namely the PV voltage) of the photovoltaic system input into the photovoltaic inverter is limited, and the load limiting when the photovoltaic inverter is overloaded is realized. Finally, through step 300, the output of the photovoltaic system is controlled according to the set PV voltage value determined in step 200, so that the output voltage can approach a given limit value (i.e., the set PV voltage value), thereby meeting the corresponding load limiting requirement.
In the prior art, the voltage output by MPPT is used as a voltage given value of the photovoltaic inverter by the traditional photovoltaic inverter, when power needs to be limited due to the conditions of over-temperature, over-frequency and the like of the photovoltaic inverter, alternating current output current is directly limited, and the energy on a bus in the middle of the photovoltaic inverter is too high in a short time, so that the voltage, the PV voltage and the like of the bus in the middle of the photovoltaic inverter are rapidly raised, at the moment, the working point of a photovoltaic system stays on the right side of the maximum power point on the PV curve, and equipment such as the photovoltaic inverter is in an easy-to-fail state, so that long-term stable operation of the equipment such as the photovoltaic inverter is not facilitated. According to the method, based on first parameter information when the photovoltaic inverter operates, whether the photovoltaic inverter needs to be limited or not is accurately judged, when the photovoltaic inverter meets the load limiting condition, a PV voltage given value smaller than or equal to a second voltage of the photovoltaic system is determined according to the second parameter information of the photovoltaic system, so that the photovoltaic inverter is over-matched and limited by limiting the PV voltage, corresponding voltage lifting of the photovoltaic inverter during over-matched and load limiting is avoided, a corresponding working point of the photovoltaic system can stay on a maximum power point or stay on the left side of the maximum power point on a PV curve according to the PV voltage given value when the photovoltaic system outputs the PV voltage, and the situation that equipment such as the photovoltaic inverter is in an easy-to-fail state due to overhigh busbar voltage, PV voltage and the like in the middle of the photovoltaic inverter when power is limited by directly limiting current is avoided, and stable operation of the photovoltaic inverter and equipment (such as the photovoltaic system, a power grid and a storage battery) connected with the photovoltaic inverter is ensured.
Optionally, the second parameter information further includes a first voltage and a first power of the output end of the photovoltaic system.
Specifically, the output voltage (referred to as the first voltage, which is also the input voltage of the photovoltaic inverter) and the output power (referred to as the first power, which is also the input power of the photovoltaic inverter) when the photovoltaic system is operating are obtained through step 100.
Determining the PV voltage setpoint for the photovoltaic system based on the second parameter information comprises:
determining a first PV given voltage according to the first power and a preset limit power; determining a second PV given voltage according to the first voltage and a preset bus voltage; the second voltage is taken as a third PV given voltage.
Specifically, according to the preset limiting power (i.e. the required power limiting value) and the first power obtained in step 100, determining a first PV given voltage of the photovoltaic system, for example, adjusting by using a corresponding PID controller (such as a PI regulator) according to a difference value between the first power and the preset limiting power, and outputting a voltage signal (denoted as the first PV given voltage) approaching to a voltage corresponding to the preset limiting power; determining a second PV given voltage of the photovoltaic system according to the preset bus voltage (namely the bus voltage of the output end of the photovoltaic system or the input end of the photovoltaic inverter to be controlled) and the first voltage obtained in the step 100, and if a corresponding PID controller (such as a PI regulator) is adopted to regulate according to the difference value between the first voltage and the preset bus voltage, outputting a voltage signal (recorded as the second PV given voltage) approaching to the preset bus voltage; step 100 is to track the maximum power point (corresponding to the maximum power) of the photovoltaic system through the MPPT module of the photovoltaic inverter, obtain the maximum power point of the photovoltaic system and the second voltage corresponding to the maximum power point, and take the second voltage as the third PV given voltage.
Step 300 includes:
and taking the minimum value of the first PV given voltage, the second PV given voltage and the third PV given voltage as a PV voltage given value, and controlling the photovoltaic system to output according to the PV voltage given value.
Specifically, taking the minimum value of the first PV given voltage, the second PV given voltage and the third PV given voltage obtained in the step 200 as a final PV voltage given value of the photovoltaic system, controlling the photovoltaic system to output according to the PV voltage given value, and realizing load limiting when the photovoltaic inverter is overloaded.
In this way, the minimum value of the first PV given voltage, the second PV given voltage and the third PV given voltage is taken as the final PV voltage given value of the photovoltaic system, so that when the photovoltaic system outputs according to the PV voltage given value to realize the over-matched load limitation of the photovoltaic inverter, the working point of the photovoltaic system can stay on the maximum power point or left side of the maximum power point on the corresponding PV curve, and the condition that equipment such as the photovoltaic inverter is in an easy fault state due to overhigh voltage of an intermediate bus of the photovoltaic inverter, the PV voltage and the like when the power is limited by directly limiting the current is avoided.
Optionally, determining the first PV given voltage according to the first power and the preset limiting power comprises:
and determining the first PV given voltage through a corresponding PI regulator according to the difference value between the first power and the preset limiting power.
Specifically, when load limiting is required to be performed on the photovoltaic inverter (i.e., the first parameter information meets the load limiting condition), comparing the first power with a preset limiting power according to the first power (which can be obtained by monitoring in real time through a monitoring device such as a sensor) and the preset limiting power (which can be preset, or a required PV power limiting value is calculated as the preset limiting power according to the design requirements of a photovoltaic system, the photovoltaic inverter or a power grid, etc.), wherein the preset limiting power is used as a given expected value, namely, the expected photovoltaic system power output, so as to obtain a power difference value; and calculating a control signal according to the power difference by adopting a corresponding PI regulator, and outputting to obtain a first PV given voltage. The PI regulator plays a role in controlling and regulating, and the output power of the photovoltaic inverter is accurately controlled through a control signal.
Therefore, when the first PV given voltage is adopted by the PV given voltage, the output power of the photovoltaic system can be stabilized near the required preset limiting power, so that the design requirements of equipment such as a photovoltaic inverter and the like are met, and the running stability and safety of the equipment such as the photovoltaic inverter and the like are improved.
Optionally, determining the second PV given voltage from the first voltage and the preset bus voltage comprises:
and determining a second PV given voltage through a corresponding PI regulator according to the difference value between the first voltage and the preset bus voltage.
Specifically, when load limiting is required to be performed on the photovoltaic inverter (i.e., the first parameter information meets the load limiting condition), according to a first voltage (which can be obtained by monitoring the bus voltage of the output end of the photovoltaic system or the input end of the photovoltaic inverter in real time through a monitoring device such as a sensor) and a preset bus voltage (which can be preset, or the bus voltage required by the output end of the photovoltaic system is calculated according to the design requirements of the photovoltaic system, the photovoltaic inverter or a power grid in the running process of the inverter, and the required bus voltage is taken as the preset bus voltage; and calculating a control signal according to the voltage difference by adopting a corresponding PI regulator, and outputting to obtain a second PV given voltage.
Therefore, the limitation and adjustment of the output bus voltage of the photovoltaic system are realized, the bus voltage at the output end of the photovoltaic system is ensured to be stabilized near the preset bus voltage, and the stable and safe operation of equipment such as a photovoltaic inverter and the like under the corresponding requirements (the design requirements of the photovoltaic inverter, the power grid requirements and the like) is ensured.
Optionally, as shown in fig. 1 and fig. 2, the second parameter information further includes a maximum limiting voltage of the bus corresponding to the output end of the photovoltaic system; step 200 comprises:
step 210, taking the minimum value of the second voltage and the maximum limiting voltage as a fourth PV given voltage;
and 220, taking the fourth PV given voltage as a PV voltage given value when the fourth PV given voltage does not meet the load limiting condition.
Specifically, in step 210, the minimum value of the second voltage and the maximum limiting voltage (which may be determined according to the design specification of the bus corresponding to the output end of the photovoltaic system, the photovoltaic inverter, the power grid, or the like) is taken as the fourth PV given voltage, so as to ensure that the output voltage of the photovoltaic system does not exceed the maximum limiting voltage of the bus of the output end of the photovoltaic system. In step 220, when the fourth PV set voltage does not meet the load limiting condition, that is, the load limiting of the photovoltaic inverter is not required, the fourth PV set voltage is taken as the PV voltage set value of the final photovoltaic system. Therefore, when the limit load of the photovoltaic inverter is realized, the output voltage of the photovoltaic system cannot exceed the maximum limit voltage of the bus at the output end of the photovoltaic system, and the stable operation of the photovoltaic inverter and other equipment is ensured.
Optionally, as shown in connection with fig. 1 and 3, after step 210, step 200 further includes:
step 250, when the fourth PV given voltage meets the load limiting condition, reducing the fourth PV given voltage by a preset value to obtain a fifth PV given voltage;
step 260, when the fifth PV set voltage does not meet the load limiting condition, taking the fifth PV set voltage as the PV voltage set value; when the fifth PV set voltage meets the load limiting condition, assigning the fifth PV set voltage to the fourth PV set voltage in step 250, and cycling from step 250 to step 260 until the finally obtained fifth PV set voltage does not meet the load limiting condition, and taking the finally obtained fifth PV set voltage as the PV voltage set value.
Specifically, after step 210, if the fourth PV set voltage obtained in step 210 meets the load limiting condition, the load of the photovoltaic inverter needs to be limited, then the fourth PV set voltage is adjusted in step 250, that is, the fourth PV set voltage is reduced by a preset value (which may be set according to the actual situation), so as to obtain a fifth PV set voltage. Thereafter, when the fifth PV set voltage does not meet the load limiting condition, i.e. no load limiting is performed on the photovoltaic inverter, the fifth PV set voltage is taken as the final PV voltage set value of the photovoltaic system for implementing the load limiting of the photovoltaic inverter through step 260; if the fifth PV set voltage obtained after the adjustment of the preset value still does not meet the load limiting condition (i.e. does not exceed the maximum limit voltage of the bus), assigning the fifth PV set voltage to the fourth PV set voltage in step 250, and cycling steps 250 to 260 until the finally obtained fifth PV set voltage does not meet the load limiting condition, and taking the finally obtained fifth PV set voltage as the PV voltage set value of the photovoltaic system for realizing the load limiting of the photovoltaic inverter.
Therefore, by setting the preset value, the fourth PV given voltage is reduced when the fourth PV given voltage meets the load limiting condition, the left shift of the working point of the photovoltaic system on the PV curve is realized, the load limiting of the photovoltaic inverter is realized, the stable operation of the photovoltaic inverter after the load limiting is ensured, the maximum power output of the photovoltaic inverter is realized, and the energy conversion efficiency of the photovoltaic system is optimized.
Optionally, step 200 includes:
judging whether the first parameter information meets the load limiting condition or not through a main DSP controller;
when the first parameter information meets the load limiting condition, a load limiting signal is sent to the slave DSP controller through the master DSP controller;
and when the load limiting signal is received from the DSP controller, determining a PV voltage given value of the photovoltaic system according to the second parameter information.
In this embodiment, the over-load limiting method of the photovoltaic inverter is executed in combination with an over-load limiting system of the photovoltaic inverter, where the over-load limiting system of the photovoltaic inverter includes a master DSP controller for ac side control of the photovoltaic inverter, a slave DSP controller for dc side control of the photovoltaic inverter, and the master DSP controller is communicatively connected with the slave DSP controller, so as to implement mutual coordination between the ac side and the dc side of the photovoltaic inverter. Specifically, in the operation process of the photovoltaic inverter, the main DSP controller can monitor, calculate, analyze and compare the first parameter information and the like in real time so as to judge whether the current operation state of the photovoltaic inverter meets the load limiting condition. If the master DSP controller judges that the running state (or the first parameter information) of the photovoltaic inverter meets the load limiting condition (such as that the output power exceeds the corresponding limiting power), the master DSP controller generates a load limiting signal and sends the load limiting signal to the slave DSP controller, namely the load limiting signal is used for informing the slave DSP controller that the photovoltaic inverter is subjected to load limiting. After receiving the load limiting signal sent by the main DSP controller, the slave DSP controller analyzes and processes the load limiting signal and the second parameter information and the like to determine a PV voltage given value of the photovoltaic system for realizing the load limiting of the photovoltaic inverter, wherein the PV voltage given value is particularly used for adjusting the output voltage of the photovoltaic system so as to meet the corresponding load limiting requirement.
Therefore, through the coordination work between the master DSP controller and the slave DSP controller, the photovoltaic inverter can stably, safely and efficiently operate under the load limiting condition, and the PV voltage given value can be dynamically adjusted according to the real-time operating condition so as to meet the corresponding load limiting requirement.
Optionally, after the master DSP controller determines that the second parameter information meets the load limiting condition for a first preset period of time, the load limiting signal is sent to the slave DSP controller, so that the running state (or the first parameter information) of the photovoltaic inverter is continuously monitored within the first preset period of time, so as to avoid the possibility of erroneous determination.
Optionally, the master DSP controller is further configured to determine a load limit value (e.g., a limit power value) of the photovoltaic inverter, and send the load limit value to the slave DSP controller. Specifically, when the power of the photovoltaic inverter needs to be limited, the master DSP controller (alternating current side control) transmits a load limiting value to the slave DSP controller (direct current side control) through master-slave communication, and the slave DSP controller gives the load limiting value to a given value of the PV power, so that the given value of the PV power is reduced, the given value of the PV voltage is reduced, the PV voltage is lowered, the working point of the photovoltaic system stays at the left side of the maximum power point of the PV curve finally, and the purposes of lowering the bus voltage at the output end of the photovoltaic system and the like are achieved.
Another embodiment of the present invention provides an overdriving limit load system of a photovoltaic inverter, including:
the acquisition unit is used for acquiring first parameter information when the photovoltaic inverter operates and second parameter information when the photovoltaic system connected with the input end of the photovoltaic inverter operates;
the operation unit is used for determining a PV voltage given value of the photovoltaic system according to the second parameter information when the first parameter information meets the load limiting condition; the set value of the PV voltage is smaller than or equal to a second voltage corresponding to the maximum power point of the photovoltaic system;
and the execution unit is used for controlling the photovoltaic system to output according to the PV voltage set value.
In the embodiment, the overdriving load limiting system of the photovoltaic inverter ensures that the overdriving load limiting method of the photovoltaic inverter can be smoothly and stably executed through the cooperation of the structures of the acquisition unit, the operation unit, the execution unit and the like; specifically, based on the first parameter information when the photovoltaic inverter is operated, whether the photovoltaic inverter needs load limiting or not is determined through the operation unit, when the photovoltaic inverter meets the load limiting condition, a given PV voltage value smaller than or equal to a second voltage of the photovoltaic system is determined through the operation unit according to the second parameter information of the photovoltaic system, which is obtained through the obtaining unit, and the photovoltaic system is controlled to output according to the given PV voltage value through the operation unit, so that the photovoltaic inverter is over-matched with the load limiting through limiting the PV voltage, corresponding voltage lifting when the photovoltaic inverter is over-matched with the load limiting is avoided, a corresponding working point when the photovoltaic system outputs according to the given PV voltage value can stay on a maximum power point or stay on the left side of the maximum power point on a PV curve, the condition that equipment such as a photovoltaic inverter is in an easy fault state due to overhigh middle bus voltage, PV voltage and the like of limiting power through directly limiting current is avoided, and stable operation of the photovoltaic inverter and equipment (such as a photovoltaic system, a power grid, a storage battery and the like) connected with the photovoltaic inverter is ensured.
Optionally, as shown in fig. 4, the superload limiting system of the photovoltaic inverter includes an MPPT module, a PWM control circuit, a Boost circuit, a current loop, a voltage loop, a power loop, a voltage limiting loop, and the loop of the current loop, the voltage loop, the power loop, the voltage limiting loop, and the loop of the voltage loop include PI regulators, and the like. Wherein P is ALLref Representing a preset limiting power, P ALLval Representing the first power, U BUSref Representing the preset bus voltage, U BUSval Representing the first voltage, V PV、 I PV Respectively representing outputs of the photovoltaic systems input to the photovoltaic inverterVoltage, output current, etc.
In order to solve the above problems, the present invention further provides a system for overdriving a photovoltaic inverter, which includes a computer readable storage medium storing a computer program and a processor, and when the computer program is read and run by the processor, the method for overdriving the photovoltaic inverter is implemented.
In this embodiment, the overdriving load limiting system of the photovoltaic inverter executes the overdriving load limiting method of the photovoltaic inverter through cooperation of structures such as a processor and a computer readable storage medium of the overdriving load limiting system of the photovoltaic inverter, so that stability of a computer program corresponding to the overdriving load limiting method of the photovoltaic inverter when the computer program is read and run by the corresponding processor can be ensured. Specifically, the overdriving load limiting system of the photovoltaic inverter is based on first parameter information when the photovoltaic inverter operates, so that whether the photovoltaic inverter needs to be subjected to load limiting or not is accurately judged, when the photovoltaic inverter meets a load limiting condition, a PV voltage given value smaller than or equal to a second voltage of the photovoltaic system is determined according to second parameter information of the photovoltaic system, and the overdriving load limiting of the photovoltaic inverter is achieved by limiting the PV voltage, namely, a corresponding working point of the photovoltaic system when the photovoltaic system outputs according to the PV voltage given value can stay on a maximum power point or stay on the left side of the maximum power point on a PV curve, and the situation that equipment such as the photovoltaic inverter is in an easy fault state due to overhigh middle bus voltage, PV voltage and the like of the photovoltaic inverter when power is limited by directly limiting current is avoided, and stable operation of the photovoltaic inverter and equipment (such as the photovoltaic system, a power grid, a storage battery and the like) connected with the photovoltaic inverter is guaranteed.
In order to solve the above problems, the present invention further provides a computer readable storage medium, where a computer program is stored, and when the computer program is read and executed by a processor, the method for over-load limiting of a photovoltaic inverter is implemented.
The technical solution of the embodiment of the present invention may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or processor to perform all or part of the steps of the method of the embodiment of the present invention. And the aforementioned storage medium includes: a usb disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk, etc.
By storing the computer program corresponding to the over-distribution load limiting method of the photovoltaic inverter through the computer readable storage medium, the stability of the computer program corresponding to the over-distribution load limiting method of the photovoltaic inverter when being read and run by a corresponding processor can be ensured.
Although the invention is disclosed above, the scope of the invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications will fall within the scope of the invention.
Claims (10)
1. The overdropping load limiting method of the photovoltaic inverter is characterized by comprising the following steps of:
acquiring first parameter information when a photovoltaic inverter operates and second parameter information when a photovoltaic system connected with an input end of the photovoltaic inverter operates;
when the first parameter information meets a load limiting condition, determining a PV voltage given value of the photovoltaic system according to the second parameter information; the PV voltage given value is smaller than or equal to a second voltage corresponding to the maximum power point of the photovoltaic system;
and controlling the photovoltaic system to output according to the PV voltage set value.
2. The method of claim 1, wherein the second parameter information includes a first voltage and a first power of the output terminal of the photovoltaic system; the determining the given value of the PV voltage of the photovoltaic system according to the second parameter information comprises:
determining a first PV given voltage according to the first power and a preset limiting power; determining a second PV given voltage according to the first voltage and a preset bus voltage; taking the second voltage as a third PV given voltage;
the controlling the photovoltaic system to output according to the PV voltage set point comprises:
and taking the minimum value of the first PV given voltage, the second PV given voltage and the third PV given voltage as the PV voltage given value, and controlling the photovoltaic system to output according to the PV voltage given value.
3. The method of overdriving a photovoltaic inverter of claim 2, wherein determining a first PV given voltage based on the first power and a preset limit power comprises:
and determining the first PV given voltage through a corresponding PI regulator according to the difference value of the first power and the preset limiting power.
4. The method of overdriving a photovoltaic inverter of claim 2, wherein determining a second PV given voltage from the first voltage and a preset bus voltage comprises:
and determining the second PV given voltage through a corresponding PI regulator according to the difference value between the first voltage and the preset bus voltage.
5. The method for overdriving a photovoltaic inverter according to claim 1, wherein the second parameter information includes a maximum limit voltage of a bus corresponding to an output end of the photovoltaic system; when the first parameter information meets the load limiting condition, determining the PV voltage given value of the photovoltaic system according to the second parameter information comprises the following steps:
taking the minimum value of the second voltage and the maximum limiting voltage as a fourth PV given voltage;
and when the fourth PV given voltage does not meet the load limiting condition, taking the fourth PV given voltage as the PV voltage given value.
6. The method according to claim 5, wherein after the minimum value between the second voltage and the maximum limit voltage is taken as a fourth PV set voltage, when the first parameter information satisfies a load limit condition, determining a PV voltage set value of the photovoltaic system according to the second parameter information further includes:
step 250, when the fourth PV set voltage meets the load limiting condition, reducing the fourth PV set voltage by a preset value to obtain a fifth PV set voltage;
step 260, when the fifth PV set voltage does not meet the load limiting condition, taking the fifth PV set voltage as the PV voltage set value; when the fifth PV set voltage meets the load limiting condition, assigning the fifth PV set voltage to the fourth PV set voltage in step 250, and looping through steps 250 to 260 until the finally obtained fifth PV set voltage does not meet the load limiting condition, and taking the finally obtained fifth PV set voltage as the PV voltage set value.
7. The method of any one of claims 1-6, wherein determining a PV voltage setpoint for the photovoltaic system based on the second parameter information when the first parameter information satisfies a load limiting condition comprises:
judging whether the first parameter information meets the load limiting condition or not through a main DSP controller;
when the first parameter information meets the load limiting condition, a load limiting signal is sent to a slave DSP controller through the master DSP controller;
and when the load limiting signal is received from the DSP controller, determining the PV voltage given value of the photovoltaic system according to the second parameter information.
8. An overrunning load limiting system for a photovoltaic inverter, comprising:
the acquisition unit is used for acquiring first parameter information when the photovoltaic inverter operates and second parameter information when the photovoltaic system connected with the input end of the photovoltaic inverter operates;
the operation unit is used for determining a PV voltage given value of the photovoltaic system according to the second parameter information when the first parameter information meets a load limiting condition; the PV voltage given value is smaller than or equal to a second voltage corresponding to the maximum power point of the photovoltaic system;
and the execution unit is used for controlling the photovoltaic system to output according to the PV voltage set value.
9. A photovoltaic inverter overdriving system comprising a computer readable storage medium storing a computer program and a processor, which computer program, when read and run by the processor, implements the photovoltaic inverter overdriving method according to any of claims 1-7.
10. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program which, when read and run by a processor, implements the method of overdriving a photovoltaic inverter according to any of claims 1-7.
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