Efficiency test system and test method for photovoltaic grid-connected energy storage type inverter

Abstract

The invention discloses an efficiency test system and test method for a photovoltaic grid-connected energy storage type inverter, and belongs to the technical field of inverters, the system comprises a photovoltaic grid-connected energy storage type inverter, a photovoltaic array simulator, a power grid simulator, a monitoring acquisition device and a monitoring upper computer; the monitoring acquisition equipment is used for acquiring a direct-current electric signal input by the photovoltaic grid-connected energy storage type inverter and an alternating-current electric signal output by the photovoltaic grid-connected energy storage type inverter, and sending the acquired data to the monitoring upper computer; the monitoring upper computer is used for controlling the photovoltaic power of different proportions input by the photovoltaic array simulator and the alternating current signal output by the power grid simulator, and according to weighting coefficients corresponding to the input photovoltaic power of different proportions, the received direct current signal input by the photovoltaic grid-connected energy storage type inverter and the received alternating current signal output by the photovoltaic grid-connected energy storage type inverter. And calculating the weighting efficiency of the photovoltaic grid-connected energy storage type inverter. The system provided by the invention can more accurately test the energy conversion efficiency of the photovoltaic grid-connected energy storage type inverter.

Description

Technical Field

[0001] The present invention belongs to the technical field of inverters, and in particular relates to an efficiency testing system and a testing method for a photovoltaic grid-connected energy storage inverter. Background Art

[0002] With the further development of renewable energy, photovoltaic grid-connected energy storage inverters in the field of solar power generation have been widely promoted in recent years as important equipment for energy conversion. With the continuous breakthroughs in photovoltaic grid-connected energy storage inverter technology and the continuous expansion of the photovoltaic market, the energy conversion efficiency of photovoltaic grid-connected energy storage inverters has become an important indicator for measuring their performance. At the same time, different climates and landforms around the world have led to corresponding weighting coefficients and weighted efficiency testing standards in various regions. Only testing steps and conditions that meet the standards can accurately evaluate the energy conversion efficiency of photovoltaic grid-connected energy storage inverters.

[0003] At present, the energy conversion efficiency test of photovoltaic grid-connected energy storage inverters mostly relies on manual testing by testers. However, this manual testing method has many problems. Testers may have a large deviation in the test results due to insufficient understanding of the test standards. In addition, the weighted efficiency curve of the photovoltaic grid-connected energy storage inverter obtained by manual testing will be significantly different from the actual weighted efficiency curve of the photovoltaic grid-connected energy storage inverter due to the different data collection time or data collection rate. At the same time, affected by the actual environment, the energy conversion efficiency deviation of the photovoltaic grid-connected energy storage inverter under different temperature conditions is also large.

[0004] Therefore, how to make the test of the energy conversion efficiency of photovoltaic grid-connected energy storage inverters more accurate is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve the above-mentioned technical problem of inaccurate energy conversion efficiency of photovoltaic grid-connected energy storage inverters when manually testing them, the present invention provides an efficiency testing system for photovoltaic grid-connected energy storage inverters to solve the above-mentioned technical problem.

[0006] In a first aspect, the present invention provides an efficiency testing system for a photovoltaic grid-connected energy storage inverter, a photovoltaic grid-connected energy storage inverter, and a photovoltaic array simulator, a power grid simulator, a monitoring and acquisition device, and a monitoring host computer respectively connected to the photovoltaic grid-connected energy storage inverter;

[0007] The photovoltaic array simulator is used to simulate the direct current signal generated by the solar cell array under different lighting conditions, and output the generated direct current signal to the photovoltaic grid-connected energy storage inverter;

[0008] The photovoltaic grid-connected energy storage inverter converts the received DC signal into an AC signal and outputs it to the power grid simulator, and converts the AC signal in the power grid simulator into a DC signal and stores it in the energy storage battery;

[0009] The power grid simulator is used to receive the AC power signal output by the photovoltaic grid-connected energy storage inverter and simulate the AC power signal output according to the power grid standards of different regions;

[0010] The monitoring and collecting equipment is used to collect the DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter, and send the collected DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter to the monitoring host computer;

[0011] The monitoring host computer is connected to the photovoltaic array simulator, the power grid simulator and the monitoring acquisition equipment respectively. The monitoring host computer is used to control the different proportions of photovoltaic power input by the photovoltaic array simulator and the alternating current signal output by the power grid simulator, and calculate the weighted efficiency of the photovoltaic grid-connected energy storage inverter according to the weighting coefficients corresponding to the different proportions of photovoltaic power input, the received direct current signal input by the photovoltaic grid-connected energy storage inverter and the alternating current signal output.

[0012] Preferably, the efficiency test system of the photovoltaic grid-connected energy storage inverter further includes a temperature chamber device;

[0013] The temperature box devices are connected to the monitoring host computer respectively, and the temperature box devices are used to input temperature information and humidity information of different regions, and send the input temperature information and humidity information of different regions to the monitoring host computer.

[0014] Preferably, the efficiency testing system of the photovoltaic grid-connected energy storage inverter further includes a temperature monitoring display;

[0015] The temperature monitoring display is connected to the photovoltaic grid-connected energy storage inverter and the monitoring host computer respectively. The temperature monitoring display is used to collect the temperature information of each point of the photovoltaic grid-connected energy storage inverter in real time, and send the collected temperature information of each point of the photovoltaic grid-connected energy storage inverter to the monitoring host computer.

[0016] Preferably, the efficiency test system of the photovoltaic grid-connected energy storage inverter further includes a data communication module, and the data communication module includes a USB serial port, a local area network interface and an RS-485 serial port;

[0017] The photovoltaic array simulator, the power grid simulator and the incubator device are connected to the monitoring host computer through a USB serial port; the monitoring acquisition device is connected to the monitoring host computer through a local area network interface; the temperature detection and display module is connected to the monitoring host computer through an RS-485 serial port.

[0018] Preferably, the monitoring and acquisition equipment is a multi-channel power analyzer.

[0019] In a second aspect, the present invention further provides an efficiency testing method for a photovoltaic grid-connected energy storage inverter, comprising:

[0020] Obtaining a direct current signal generated by a solar cell array under different illumination conditions simulated by a photovoltaic array simulator, and outputting the generated direct current signal to a photovoltaic grid-connected energy storage inverter;

[0021] The photovoltaic grid-connected energy storage inverter converts the received DC signal into an AC signal and outputs it to the power grid simulator, and converts the AC signal in the power grid simulator into a DC signal and stores it in the energy storage battery;

[0022] Obtain the AC power signal output by the photovoltaic grid-connected energy storage inverter received by the grid simulator, and simulate the AC power signal output according to the grid standards of different regions;

[0023] The DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter are collected by the monitoring and collecting equipment, and the collected DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter are sent to the monitoring host computer;

[0024] By monitoring the different proportions of photovoltaic power input by the upper computer and the AC power signal output by the power grid simulator, and according to the weighting coefficients corresponding to the different proportions of photovoltaic power input, the received DC power signal input by the photovoltaic grid-connected energy storage inverter and the AC power signal output, the weighted efficiency of the photovoltaic grid-connected energy storage inverter is calculated.

[0025] Preferably, the weighted efficiency of the photovoltaic grid-connected energy storage inverter is calculated according to the weighted coefficients corresponding to the different proportions of the input photovoltaic power, the received DC signal input by the photovoltaic grid-connected energy storage inverter, and the AC signal output, including:

[0026] The calculation formula of the weighted efficiency η of the photovoltaic grid-connected energy storage inverter is:

[0027]

[0028] Among them, n represents n different proportions of photovoltaic power, p i-inrepresents the i-th proportion of DC power input from the photovoltaic array simulator to the photovoltaic grid-connected energy storage inverter, p i-out Represents the i-th proportion of AC power output from the photovoltaic grid-connected energy storage inverter to the grid, W i Indicates the weighting coefficient corresponding to the i-th proportion of the input photovoltaic power.

[0029] Preferably, after calculating the weighted efficiency of the photovoltaic grid-connected energy storage inverter, the method further includes:

[0030] Presetting a qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter, and comparing the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter with the preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter;

[0031] According to the comparison result of the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter and the preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter, it is judged whether the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified.

[0032] Preferably, the method of comparing the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter with a preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter to determine whether the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified includes:

[0033] If the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is greater than 85%, the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified;

[0034] If the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is less than or equal to 85%, the efficiency of the tested photovoltaic grid-connected energy storage inverter is unqualified.

[0035] Preferably, the method further comprises:

[0036] The temperature information of each point of the photovoltaic grid-connected energy storage inverter is collected in real time through a temperature monitoring display, and the collected temperature information of each point of the photovoltaic grid-connected energy storage inverter is sent to a monitoring host computer;

[0037] The monitoring host computer generates an ambient temperature curve of each point of the photovoltaic grid-connected energy storage inverter according to the received temperature information of each point of the photovoltaic grid-connected energy storage inverter.

[0038] Compared with the prior art, the efficiency testing system and testing method of the photovoltaic grid-connected energy storage inverter provided by the present invention can more accurately test the energy conversion efficiency of the photovoltaic grid-connected energy storage inverter by monitoring the photovoltaic power of different proportions input by the upper computer and the AC power signal output by the power grid simulator, and calculate the weighted efficiency of the photovoltaic grid-connected energy storage inverter according to the weighting coefficients corresponding to the different proportions of the input photovoltaic power, the received DC power signal input by the photovoltaic grid-connected energy storage inverter and the AC power signal output. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only part of the embodiments of the present invention, rather than all of the embodiments. For ordinary technicians in this field, without paying creative work, other drawings obtained based on these drawings all fall within the scope of protection of the present invention.

[0040] Figure 1 A schematic diagram of the framework structure of an efficiency testing system for a photovoltaic grid-connected energy storage inverter provided by an embodiment of the present invention;

[0041] Figure 2 An application flow chart of an efficiency testing system for a photovoltaic grid-connected energy storage inverter provided by an embodiment of the present invention;

[0042] Figure 3 A schematic flow chart of an efficiency testing method for a photovoltaic grid-connected energy storage inverter provided in an embodiment of the present invention.

[0043] Among them, 10 is a photovoltaic grid-connected energy storage inverter, 20 is a photovoltaic array simulator, 30 is a power grid simulator, 40 is a monitoring and acquisition device, 50 is a monitoring host computer, 60 is a temperature box device, and 70 is a temperature monitoring display. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] In order to make the description of the content of the present invention more detailed and complete, the following is an illustrative description of the implementation method and specific examples of the present invention; however, this is not the only form of implementing or applying the specific embodiments of the present invention. The implementation method covers the features of multiple specific embodiments and the method steps and their sequence for constructing and operating these specific embodiments. However, other specific embodiments can also be used to achieve the same or equal functions and step sequences. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0047] In the description of the embodiments of the present invention, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, “multiple” means two or more than two, and other quantifiers are similar. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention, and the embodiments of the present invention and the features in the embodiments may be combined with each other without conflict.

[0048] In order to solve the technical problem of inaccurate energy conversion efficiency of photovoltaic grid-connected energy storage inverters when manually testing them, the present invention provides an efficiency testing system for photovoltaic grid-connected energy storage inverters. Figure 1, is a schematic diagram of the framework structure of an efficiency test system for a photovoltaic grid-connected energy storage inverter provided in an embodiment of the present invention, the system comprising a photovoltaic grid-connected energy storage inverter 10 and a photovoltaic array simulator 20, a power grid simulator 30, a monitoring and acquisition device 40 and a monitoring host computer 50 respectively connected to the photovoltaic grid-connected energy storage inverter 10; the photovoltaic array simulator 20 is used to simulate the DC signal generated by the solar cell array under different lighting conditions, and output the generated DC signal to the photovoltaic grid-connected energy storage inverter 10; the photovoltaic grid-connected energy storage inverter 10 converts the received DC signal into an AC signal and outputs it to the power grid simulator 30, and converts the AC signal in the power grid simulator 30 into a DC signal and stores it in an energy storage battery; the power grid simulator 30 is used to receive the AC signal output by the photovoltaic grid-connected energy storage inverter 10 signal, and simulate the output AC signal specified by the power grid standards of different regions; the monitoring and acquisition equipment 40 is used to collect the DC signal input and the AC signal output of the photovoltaic grid-connected energy storage inverter 10, and send the collected DC signal input and the AC signal output of the photovoltaic grid-connected energy storage inverter 10 to the monitoring host computer 50; the monitoring host computer 50 is respectively connected to the photovoltaic array simulator 20, the power grid simulator 30 and the monitoring and acquisition equipment 40, and the monitoring host computer 50 is used to control the different proportions of photovoltaic power input by the photovoltaic array simulator 20 and the AC signal output by the power grid simulator 30, and calculate the weighted efficiency of the photovoltaic grid-connected energy storage inverter 10 according to the weighting coefficients corresponding to the different proportions of photovoltaic power input, the received DC signal input and the AC signal output by the photovoltaic grid-connected energy storage inverter 10. In the embodiment of the present invention, by monitoring the upper computer 50 to control the different proportions of photovoltaic power input by the photovoltaic array simulator 10 and the AC signal output by the power grid simulator 30, the performance of the photovoltaic grid-connected energy storage inverter in a complex and changeable environment can be more accurately evaluated. In addition, the weighted efficiency of the photovoltaic grid-connected energy storage inverter 10 is calculated by combining the weighted coefficients corresponding to the different proportions of photovoltaic power input, which can more reasonably reflect the impact of different working conditions on the overall performance of the photovoltaic grid-connected energy storage inverter, and can more accurately test the energy conversion efficiency of the photovoltaic grid-connected energy storage inverter, and reduce the testing cost.

[0049] Specifically, in the embodiment of the present invention, the monitoring host computer 50 is used to control and monitor the efficiency test system of the entire photovoltaic grid-connected energy storage inverter. The test case configuration parameters set by the monitoring host computer 50 can control the photovoltaic array simulator 20 to output different photovoltaic panel coefficient current signals and voltage signals, UP curve output and UI curve output. At the same time, by controlling the output configuration value of the power grid simulator 30, different output power grid voltage and frequency levels are set. Among them, the photovoltaic array simulator 20 can select a programmable photovoltaic array simulator 20, and the programmable photovoltaic array simulator 20 can be used to receive the configuration parameters input by the monitoring host computer 50, and perform UP curve output and UI curve output of different photovoltaic panel coefficients. The voltage signal and current signal output by the photovoltaic array simulator 20 need to meet the requirements of general photovoltaic strings. The output range of the voltage signal is 0-1500V, and the output range of the current signal is 0-60A. In addition, the power grid simulator 30 can select a programmable power grid simulator 30, which can be used to program simulation input to configure parameter files of power grid regulations in different countries and regions, such as European EN50549, American IEEE1547, German VDE-AR-N4105, Australian AS4777, national standard GB / T32004, etc.

[0050] As an implementation mode, the efficiency test system of the photovoltaic grid-connected energy storage inverter further includes a thermostat device 60; the thermostat device 60 is respectively connected to the monitoring host computer 50, and the thermostat device 60 is used to input the temperature information and humidity information of different regions, and send the input temperature information and humidity information of different regions to the monitoring host computer 50. Specifically, in the embodiment of the present invention, the thermostat device 60 can select a programmable walk-in thermostat, and the programmable walk-in thermostat can be programmed to simulate the input of local temperature and humidity condition parameter configurations of different countries and regions. The thermostat device 60 feeds back the ambient temperature conditions collected by itself to the monitoring host computer 50 to control the startup and shutdown of the programmable photovoltaic array simulator 20 and the programmable power grid simulator 30.

[0051] As an implementation mode, the efficiency test system of the photovoltaic grid-connected energy storage inverter further includes a temperature monitoring display 70; the temperature monitoring display 70 is respectively connected to the photovoltaic grid-connected energy storage inverter and the monitoring host computer 50, and the temperature monitoring display 70 is used to collect the temperature information of each point of the photovoltaic grid-connected energy storage inverter in real time, and send the collected temperature information of each point of the photovoltaic grid-connected energy storage inverter to the monitoring host computer 50. Specifically, the temperature monitoring display 70 is composed of 4 panels, each of which is a 16-channel differential thermocouple input module, and its AD resolution is as high as 128 bits, and it can connect up to 64 K-type thermocouple temperature measurement lines, and the temperature measurement range is between -40°C and 1000°C, and the temperature detection of 128 points at the location of the sample components can be carried out simultaneously.

[0052] As an implementation mode, the efficiency test system of the photovoltaic grid-connected energy storage inverter further includes a data communication module, which includes a USB serial port, a local area network interface and an RS-485 serial port; the photovoltaic array simulator 20, the power grid simulator 30 and the temperature box device 60 are connected to the monitoring host computer 50 through the USB serial port; the monitoring acquisition device 40 is connected to the monitoring host computer 50 through the local area network interface; the temperature detection display module is connected to the monitoring host computer 50 through the RS-485 serial port. Specifically, in the embodiment of the present invention, the monitoring host computer 50 can communicate with the program photovoltaic array simulator 20 and the program power grid simulator 30 through the USB serial port, and at the same time, the monitoring host computer 50 can communicate with the temperature monitoring display 70 through the RS-485 serial port, and its communication baud rate is 9600bps. The monitoring host computer 50 generates a temperature and humidity curve based on the data collected by the temperature monitoring display, so as to analyze the temperature rise of each component of the photovoltaic grid-connected energy storage inverter and the life of the fuselage components under different efficiency point working conditions.

[0053] As an implementation mode, the monitoring and acquisition device 40 is a multi-channel power analyzer. Specifically, in an embodiment of the present invention, the monitoring and acquisition device 40 is a multi-channel power analyzer, and the monitoring host computer 50 can communicate with the multi-channel power analyzer through a local area network interface. The multi-channel power analyzer supports at least 8-channel voltage signal and current signal collection, wherein the current signal can be collected by connecting in series to the photovoltaic grid-connected energy storage inverter loop, or by means of a current probe. In addition, the multi-channel power analyzer sets the IPV4 address through the Ethernet network port of the monitoring host computer 50 for matching communication, and then outputs and saves the voltage signal, current signal, active power, apparent power and frequency and other parameters of the multi-power analyzer monitored by the monitoring host computer 50 in the form of a CSV file. Finally, the host computer summarizes, analyzes and organizes the data collected by the multi-power analyzer and the data collected by the temperature monitoring display, and outputs the results in the form of tables and curves, which are displayed on the user report.

[0054] In order to verify the effectiveness of the above-mentioned photovoltaic grid-connected energy storage inverter efficiency test system, the embodiment of the present invention has been actually applied to it. Please refer to Figure 2 , Figure 2 The application process of an efficiency test system for a photovoltaic grid-connected energy storage inverter provided by an embodiment of the present invention may include the following steps:

[0055] When the present invention is applied to the efficiency test system of the photovoltaic grid-connected energy storage inverter, the first step is to log in and register the account of the monitoring host computer. The server account authorization method can be used to log in to the monitoring host computer. If the account is not registered, the login is prohibited to prevent outsiders from tampering with the test configuration file, thereby causing the tested sample to fail and be damaged. The account form is bound to the IP of the authorized computer; after successfully logging in to the test host computer, the second step begins, the hardware communication and connection of the efficiency test system of the photovoltaic grid-connected energy storage inverter. In this process, it is necessary to confirm whether the communication between the data source end and the computer is normal, and check whether the computer has installed and supports the USB serial port and RS-485 serial port driver. Then, select the relevant port (COM) and Ethernet configuration address in the monitoring host computer to ensure that the communication address of the monitoring host computer is consistent with that of the multi-power analyzer, so as to ensure the effective control of the photovoltaic array simulator and the power grid simulator by the monitoring host computer and the normal monitoring of the collected data; after checking that the hardware communication and connection of the efficiency test system of the photovoltaic grid-connected energy storage inverter are normal, the third step begins, selecting the power grid regulations of the relevant countries and regions through the power grid simulator, and selecting the UP curve output and photovoltaic coefficient of the photovoltaic input through the photovoltaic array simulator. If the test is conducted domestically, the Chinese power grid standard (220V / 50Hz) can be selected. When selecting the photovoltaic panel coefficient, the monitoring host computer currently supports two common photovoltaic panel types: crystalline silicon and thin film. After checking the crystalline silicon, the system will display various coefficients of the crystalline silicon panel for filling in, and then you can choose to test the power and voltage. The monitoring host computer can generate a power curve from 0-100%, and the photovoltaic input power ratio will be attached below the curve, including 5%, 10%, 15%, 20%, 25%, 50%, 75%, 100% and other different ratios. You can also directly select in the country and region drop-down box, and the system will generate a weighted power curve accordingly; after selecting the grid regulations of the relevant country and region and the photovoltaic input power ratio, the fourth step begins, setting the parameter configuration of the temperature monitoring display, and using the purchased current probe and K-type thermocouple temperature measurement line to set the corresponding proportional coefficient. Specifically, export the initialization file from the parameter configuration file of the monitoring host computer. If you want to continue to use it later, you can directly import the initialization configuration file, so that you can reuse the proportional coefficient of the acquisition device.If the parameter configuration written into the monitoring host computer exceeds the measurement range, the system will prompt a "re-write" alarm message to ensure the accuracy of the parameter configuration of the temperature monitoring display; when the parameters of the temperature monitoring display are successfully configured, the fifth step begins, starting the test: click the start test button, the running light of the monitoring host computer turns green, indicating that the test has started, and the host computer interface displays the collected test data in the form of a chart. The collected test data includes the UP curve output of the photovoltaic simulator, the voltage signal, current signal and frequency real-time data of the power grid simulator, the actual ambient temperature curve of the temperature chamber, the temperature channel data of each point of the photovoltaic grid-connected energy storage inverter monitored by the temperature monitoring display, and the real-time voltage signal, real-time current signal, real-time active power, real-time apparent power and harmonic data of the photovoltaic grid-connected energy storage inverter collected by the multi-power analyzer. All these data will be summarized in a scrolling table interface for easy viewing and analysis. If an abnormality occurs during the test, the system will generate a relevant alarm, and the test indicator light on the system display interface will change from green to red, to remind the tester that there is a problem with the test. If the test is stopped midway, the display indicator light will turn yellow. When the test is restarted, the indicator light will change from yellow back to green, indicating that the test continues normally. All data during the test can be automatically saved to the computer in the form of CSV files, with a saving time of 1s / frame and a saving cycle range of 200ms-5s, so that the data can be exported after the test for manual analysis and calculation, and can also be directly generated through weighted efficiency curves and ambient temperature curves for intuitive analysis and observation.

[0056] Based on the above-mentioned photovoltaic grid-connected energy storage inverter efficiency test system, the embodiment of the present invention provides a photovoltaic grid-connected energy storage inverter efficiency test method, please refer to Figure 3 , Figure 3 A schematic flow chart of an efficiency testing method for a photovoltaic grid-connected energy storage inverter provided by an embodiment of the present invention, the method specifically includes:

[0057] Step S101, obtaining the DC signal generated by the solar cell array under different lighting conditions simulated by the photovoltaic array simulator, and outputting the generated DC signal to the photovoltaic grid-connected energy storage inverter; Step S102, the photovoltaic grid-connected energy storage inverter converts the received DC signal into an AC signal and outputs it to the power grid simulator, and converts the AC signal in the power grid simulator into a DC signal and stores it in the energy storage battery; Step S103, obtaining the AC signal output by the photovoltaic grid-connected energy storage inverter received by the power grid simulator, and simulating the AC signal output according to the power grid standards of different regions; Step S1 04. Collect the DC signal input and AC signal output of the photovoltaic grid-connected energy storage inverter through monitoring and collection equipment, and send the collected DC signal input and AC signal output of the photovoltaic grid-connected energy storage inverter to the monitoring host computer; step S105. Control the photovoltaic power input of the photovoltaic array simulator and the AC signal output of the power grid simulator in different proportions through the monitoring host computer, and calculate the weighted efficiency of the photovoltaic grid-connected energy storage inverter according to the weighting coefficients corresponding to the different proportions of the input photovoltaic power, the received DC signal input and AC signal output of the photovoltaic grid-connected energy storage inverter. In the embodiment of the present invention, by monitoring the host computer to control the photovoltaic power input of the photovoltaic array simulator and the AC signal output of the power grid simulator in different proportions, the performance of the photovoltaic grid-connected energy storage inverter in complex and changeable environments can be more accurately evaluated. In addition, calculating the weighted efficiency of the photovoltaic grid-connected energy storage inverter by combining the weighted coefficients corresponding to the different proportions of input photovoltaic power can more reasonably reflect the impact of different working conditions on the overall performance of the photovoltaic grid-connected energy storage inverter, and can more accurately test the energy conversion efficiency of the photovoltaic grid-connected energy storage inverter, and effectively reduce the testing cost.

[0058] Specifically, in the embodiment of the present invention, the software function of the efficiency test method of the photovoltaic grid-connected energy storage inverter is realized by relying on the development of the finite state machine model, which is a software logic architecture used to control the behavior of the system and data flow path, and it consists of a set of finite states and conversion functions defined on these states. The monitoring host computer in the present invention uses this model as the realization of the logic judgment timing function of the monitoring host computer. The efficiency test method of the photovoltaic grid-connected energy storage inverter of the present invention is designed with 6 stages to ensure the standardization and accuracy of the abnormal judgment of the results and the test process by the monitoring host computer during the test. The first stage is the initialization stage. In this stage, the monitoring host computer reads the configuration file parameters of the photovoltaic array simulator, the power grid simulator, the incubator, and the data acquisition serial port. In the incubator configuration stage, the incubator will collect the ambient temperature in real time and return a maximum temperature value as a start-up threshold condition of the monitoring host computer. If the ambient temperature of the incubator reaches the set start-up condition, the display light turns green, and the operation of the next stage is allowed at this time. If the ambient temperature of the incubator does not reach the set condition, the startup test state of the host computer cannot be enabled, that is, the test process is suspended here, waiting for the incubator environment to meet the conditions. In the configuration reading phase, if the monitoring host computer fails to read the configuration file, the entire test process will directly enter the test end phase. It is necessary to check whether the configuration file is correct. Only after confirming that the configuration file is correct can the next test phase be entered.

[0059] After the above initialization phase is completed, the monitoring host computer enters the second phase, namely the operating condition test and monitoring phase. In this phase, the monitoring host computer selects different power ratios of the photovoltaic array simulator and the regulatory voltage range and frequency range of the photovoltaic grid-connected energy storage inverter corresponding to the power grid simulator. At the same time, the monitoring host computer turns on the data monitoring of the multi-power analyzer and the temperature monitoring display to monitor the changes in the voltage signal, current signal and power data of the input and output of the photovoltaic grid-connected energy storage inverter in real time. In addition, the monitoring host computer obtains the highest ambient temperature data collected by the temperature monitoring display to analyze and monitor the temperature rise of each component of the photovoltaic grid-connected energy storage inverter during the entire test process.

[0060] After the working condition test and monitoring stage is over, the monitoring host computer enters the third stage, namely the power switching and static stage. In the photovoltaic grid-connected working condition operation stage, data processing and analysis work is carried out at the same time. First, the data collected by the multi-power analyzer is output with voltage as the X-axis and power as the Y-axis to output the real-time UP curve, and the data collected by the temperature collector is output with time as the X-axis and temperature as the Y-axis to output the real-time temperature curve. In the initial stage of the software, 1 minute of real-time data will be read, and the maximum current will be determined for the read real-time data. If the input current is continuously lower than 0.05A, it is determined that there is a problem with the input power configuration of the photovoltaic source. If it is determined that there is a problem with the photovoltaic source configuration, the test will be exited and the user will be waited for to reselect the photovoltaic configuration or check the abnormality of the photovoltaic source. In this stage, the host computer continues to collect data from the multi-power analyzer. If the abnormality of the photovoltaic source is not determined, the collection time is 0.5 seconds. If the photovoltaic source is normal, the average input voltage and input current are collected and calculated, and the collection time is 3 minutes.

[0061] After the working condition test and monitoring stage and the power switching and static stage are completed, the monitoring host computer enters the fourth stage, namely the data analysis and processing stage. The inverter is in the grid-connected standby state. The monitoring host computer continuously detects the changes in the voltage signal, current signal and power data of the photovoltaic grid-connected energy storage inverter input and output, and the component temperature data, and calculates the weighted efficiency of the photovoltaic grid-connected energy storage inverter according to the weighted coefficients corresponding to the different proportions of the input photovoltaic power, the received DC signal input and the AC signal output by the photovoltaic grid-connected energy storage inverter. If the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is less than or equal to 30%, it is necessary to check whether the hardware configuration of the photovoltaic grid-connected energy storage inverter is abnormal; if the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is greater than 30%, the current data is saved, and the monitoring of the monitoring host computer is turned on at the same time. Among them, the domestic weighted efficiency coefficient is calculated according to the "Weighted Efficiency and Evaluation Technical Conditions for Photovoltaic Grid-connected Inverters in Typical Solar Resource Areas in China". The weighted efficiency coefficients of photovoltaic grid-connected inverters in typical solar resource areas in China are shown in Table 1. For foreign countries, the European region is based on the Munich area in Germany, and the United States uses the California area. The weighted coefficients of foreign regions are shown in Table 2:

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066] After analyzing and processing the data of the monitoring host computer, the monitoring host computer enters the fifth stage, that is, the table and curve generation stage. In this stage, the maximum value of the weighted efficiency under each photovoltaic power ratio can be taken, and the weighted coefficient curve can be drawn based on this data. In this way, the weighted efficiency under different photovoltaic power ratios can be intuitively displayed. All components are sorted according to the highest temperature, output in the form of a table, and drawn into a word report. After drawing the table and curve, the test is over, and the monitoring host computer enters the sixth stage. The monitoring host computer stops the equipment operation and generates a report for the engineer to analyze the report.

[0067] As an implementation mode, the weighted efficiency of the photovoltaic grid-connected energy storage inverter is calculated according to the weighted coefficients corresponding to the different proportions of the input photovoltaic power, the received DC signal input by the photovoltaic grid-connected energy storage inverter, and the AC signal output, including:

[0068] The calculation formula of the weighted efficiency η of the photovoltaic grid-connected energy storage inverter is:

[0069]

[0070] Among them, n represents n different proportions of photovoltaic power, p i-in represents the i-th proportion of DC power input from the photovoltaic array simulator to the photovoltaic grid-connected energy storage inverter, p i-out Represents the i-th proportion of AC power output from the photovoltaic grid-connected energy storage inverter to the grid, W i Indicates the weighting coefficient corresponding to the i-th proportion of the input photovoltaic power.

[0071] As an implementation mode, after calculating the weighted efficiency of the photovoltaic grid-connected energy storage inverter, the method further includes: presetting a qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter, and comparing the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter with the preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter; judging whether the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified based on the comparison result of the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter and the preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter. The present invention judges whether the efficiency of the photovoltaic grid-connected energy storage inverter is qualified based on the qualified threshold value of the weighted efficiency, which helps to screen out photovoltaic grid-connected energy storage inverter products that meet quality standards or adjust and improve unqualified products.

[0072] As an implementation mode, the method of comparing the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter with the preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter to determine whether the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified includes: if the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is greater than 85%, the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified; if the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is less than or equal to 85%, the efficiency of the tested photovoltaic grid-connected energy storage inverter is unqualified. Specifically, in an embodiment of the present invention, when the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is greater than 85%, it is determined that the efficiency of the photovoltaic grid-connected energy storage inverter is qualified, the performance reaches the expected efficiency standard, can meet normal use requirements, and can effectively convert and store electric energy in the photovoltaic grid-connected energy storage system to ensure the operating efficiency of the entire system. If the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is less than or equal to 85%, the efficiency of the photovoltaic grid-connected energy storage inverter is considered to be unqualified. The inverter may have large losses in the energy conversion process and cannot effectively connect and store the electricity generated by the photovoltaic cells. This may affect the power generation efficiency and performance of the entire photovoltaic grid-connected energy storage system. The photovoltaic grid-connected energy storage inverter needs to be further inspected, repaired or replaced.

[0073] As an implementation mode, the method further includes: collecting temperature information of each point of the photovoltaic grid-connected energy storage inverter in real time through a temperature monitoring display, and sending the collected temperature information of each point of the photovoltaic grid-connected energy storage inverter to a monitoring host computer; the monitoring host computer generates an ambient temperature curve of each point of the photovoltaic grid-connected energy storage inverter according to the received temperature information of each point of the photovoltaic grid-connected energy storage inverter. In the present invention, the generated ambient temperature curve of each point of the photovoltaic grid-connected energy storage inverter can intuitively show the temperature change trend of different points over time. By observing the ambient temperature curve, technicians can easily find out whether the temperature is abnormally high or fluctuates too much, so as to timely judge whether the inverter has potential overheating problems or other temperature-related fault hazards, so as to take corresponding measures to ensure the normal operation of the photovoltaic grid-connected energy storage inverter.

[0074] The efficiency testing method based on the photovoltaic grid-connected energy storage inverter provided in the embodiment of the present invention can execute the technical solution of the efficiency testing system of the photovoltaic grid-connected energy storage inverter in any of the above embodiments. Its implementation principle and beneficial effects are similar to the implementation principle and beneficial effects of the efficiency testing system of the photovoltaic grid-connected energy storage inverter. Please refer to the implementation principle and beneficial effects of the efficiency testing system of the photovoltaic grid-connected energy storage inverter, which will not be repeated here.

[0075] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0076] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units. The above is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

[0077] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above in the form of preferred embodiments, it is not intended to limit the present invention. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An efficiency test system for a photovoltaic grid-connected energy storage inverter, characterized in that: include: A photovoltaic grid-connected energy storage inverter and a photovoltaic array simulator, a power grid simulator, a monitoring and acquisition device and a monitoring host computer respectively connected to the photovoltaic grid-connected energy storage inverter; The photovoltaic array simulator is used to simulate the direct current signal generated by the solar cell array under different lighting conditions, and output the generated direct current signal to the photovoltaic grid-connected energy storage inverter; The photovoltaic grid-connected energy storage inverter converts the received DC signal into an AC signal and outputs it to the power grid simulator, and converts the AC signal in the power grid simulator into a DC signal and stores it in the energy storage battery; The power grid simulator is used to receive the AC power signal output by the photovoltaic grid-connected energy storage inverter and simulate the AC power signal output according to the power grid standards of different regions; The monitoring and collecting equipment is used to collect the DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter, and send the collected DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter to the monitoring host computer; The monitoring host computer is connected to the photovoltaic array simulator, the power grid simulator and the monitoring acquisition equipment respectively. The monitoring host computer is used to control the different proportions of photovoltaic power input by the photovoltaic array simulator and the alternating current signal output by the power grid simulator, and calculate the weighted efficiency of the photovoltaic grid-connected energy storage inverter according to the weighting coefficients corresponding to the different proportions of photovoltaic power input, the received direct current signal input by the photovoltaic grid-connected energy storage inverter and the alternating current signal output.

2. The efficiency test system of the photovoltaic grid-connected energy storage inverter according to claim 1, characterized in that: The efficiency testing system of the photovoltaic grid-connected energy storage inverter also includes a temperature chamber device; The temperature box devices are connected to the monitoring host computer respectively, and the temperature box devices are used to input temperature information and humidity information of different regions, and send the input temperature information and humidity information of different regions to the monitoring host computer.

3. The efficiency test system of the photovoltaic grid-connected energy storage inverter according to claim 2, characterized in that: The efficiency testing system of the photovoltaic grid-connected energy storage inverter also includes a temperature monitoring display; The temperature monitoring display is connected to the photovoltaic grid-connected energy storage inverter and the monitoring host computer respectively. The temperature monitoring display is used to collect the temperature information of each point of the photovoltaic grid-connected energy storage inverter in real time, and send the collected temperature information of each point of the photovoltaic grid-connected energy storage inverter to the monitoring host computer.

4. The efficiency test system of the photovoltaic grid-connected energy storage inverter according to claim 3, characterized in that: The efficiency test system of the photovoltaic grid-connected energy storage inverter also includes a data communication module, and the data communication module includes a USB serial port, a local area network interface and an RS-485 serial port; The photovoltaic array simulator, the power grid simulator and the incubator device are connected to the monitoring host computer through a USB serial port; the monitoring acquisition device is connected to the monitoring host computer through a local area network interface; the temperature detection and display module is connected to the monitoring host computer through an RS-485 serial port.

5. The efficiency test system of the photovoltaic grid-connected energy storage inverter according to claim 4, characterized in that: The monitoring and acquisition equipment is a multi-channel power analyzer.

6. A method for testing the efficiency of a photovoltaic grid-connected energy storage inverter, characterized in that: include: Obtaining a direct current signal generated by a solar cell array under different illumination conditions simulated by a photovoltaic array simulator, and outputting the generated direct current signal to a photovoltaic grid-connected energy storage inverter; The photovoltaic grid-connected energy storage inverter converts the received DC signal into an AC signal and outputs it to the power grid simulator, and converts the AC signal in the power grid simulator into a DC signal and stores it in the energy storage battery; Obtain the AC power signal output by the photovoltaic grid-connected energy storage inverter received by the grid simulator, and simulate the AC power signal output according to the grid standards of different regions; The DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter are collected by the monitoring and collecting equipment, and the collected DC power signal input and the AC power signal output of the photovoltaic grid-connected energy storage inverter are sent to the monitoring host computer; By monitoring the different proportions of photovoltaic power input by the upper computer and the AC power signal output by the power grid simulator, and according to the weighting coefficients corresponding to the different proportions of photovoltaic power input, the received DC power signal input by the photovoltaic grid-connected energy storage inverter and the AC power signal output, the weighted efficiency of the photovoltaic grid-connected energy storage inverter is calculated.

7. The efficiency testing method of the photovoltaic grid-connected energy storage inverter according to claim 6, characterized in that: The weighted efficiency of the photovoltaic grid-connected energy storage inverter is calculated according to the weighted coefficients corresponding to the different proportions of the input photovoltaic power, the received DC signal input by the photovoltaic grid-connected energy storage inverter and the AC signal output, including: The calculation formula of the weighted efficiency η of the photovoltaic grid-connected energy storage inverter is: Among them, n represents n different proportions of photovoltaic power, p i-in represents the i-th proportion of DC power input from the photovoltaic array simulator to the photovoltaic grid-connected energy storage inverter, p i-out Represents the i-th proportion of AC power output from the photovoltaic grid-connected energy storage inverter to the grid, W i Indicates the weighting coefficient corresponding to the i-th proportion of the input photovoltaic power.

8. The efficiency testing method of the photovoltaic grid-connected energy storage inverter according to claim 7, characterized in that: After calculating the weighted efficiency of the photovoltaic grid-connected energy storage inverter, the method further includes: Presetting a qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter, and comparing the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter with the preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter; According to the comparison result of the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter and the preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter, it is judged whether the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified.

9. The efficiency testing method of the photovoltaic grid-connected energy storage inverter according to claim 8, characterized in that: The method comprises comparing the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter with a preset qualified threshold value of the weighted efficiency of the photovoltaic grid-connected energy storage inverter to determine whether the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified, including: If the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is greater than 85%, the efficiency of the tested photovoltaic grid-connected energy storage inverter is qualified; If the calculated weighted efficiency of the photovoltaic grid-connected energy storage inverter is less than or equal to 85%, the efficiency of the tested photovoltaic grid-connected energy storage inverter is unqualified.

10. The efficiency testing method of the photovoltaic grid-connected energy storage inverter according to claim 9, characterized in that: The method further comprises: The temperature information of each point of the photovoltaic grid-connected energy storage inverter is collected in real time through a temperature monitoring display, and the collected temperature information of each point of the photovoltaic grid-connected energy storage inverter is sent to a monitoring host computer; The monitoring host computer generates an ambient temperature curve of each point of the photovoltaic grid-connected energy storage inverter according to the received temperature information of each point of the photovoltaic grid-connected energy storage inverter.

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