Photovoltaic inverter testing device

Abstract

The utility model provides a testing device for a photovoltaic inverter. The device is used for solving the technical problems that an existing photovoltaic inverter test device is inaccurate in test data, poor test products affect the performance of test equipment, an RLC load device is not arranged, a power grid simulator is large in volume noise, the voltage adaptation range of a photovoltaic inverter cannot be detected in a refined mode, and a direct-current and alternating-current simulation unit is required to be high in capacity. The photovoltaic inverter testing device comprises a power grid simulator, an RLC electronic load and a PV simulator, and the input ends of the power grid simulator, the RLC electronic load and the PV simulator take power from a power grid interface so as to carry out grid-connected and off-grid tests. Meanwhile, the power grid simulator and the RLC electronic load are both of a bidirectional feed network structure, the PV simulator supplies direct-current / alternating-current electric energy to the photovoltaic inverter to be tested through the DC output interface, the alternating-current / direct-current output of the photovoltaic inverter to be tested feeds the electric energy back to the power grid simulator and the RLC electronic load, and then the electric energy is fed back to the power grid interface, so that the electric energy loss in the testing process is greatly reduced.

Description

Technical Field

[0001] The utility model relates to a testing device, in particular to a photovoltaic inverter testing device. Background Art

[0002] On May 11, 2021, the National Energy Administration issued a notice on matters related to the development and construction of wind power and photovoltaic power generation in 2021 (Guonengfaxinneng

[2021] No. 25): The general requirements pointed out the active implementation of the carbon peak and carbon neutrality goals, as well as the non-fossil energy in primary energy consumption reaching about 25% by 2030, and the total installed capacity of wind power and solar power generation reaching more than 1.2 billion kilowatts. The photovoltaic inverter is an indispensable core device of the photovoltaic power generation system, and its own performance is related to the reliability of grid operation and power supply quality. Therefore, in the process of manufacturing and testing photovoltaic inverters, various performance indicators including MPPT efficiency, fault ride-through, island protection function, frequency adaptability, harmonic adaptability, voltage sag, short-term interruption, etc. must be tested to ensure that the photovoltaic inverter meets the relevant design standards.

[0003] In recent years, many photovoltaic inverter test devices have appeared, but these devices have different types of problems due to different settings: First, the output end of the power grid simulator is connected to the output end of the photovoltaic inverter to be tested and the input end of the photovoltaic DC simulation unit. Even if there is an electrical isolation device in this setting, during the inverter test, the adjustment of the power grid simulation source and the output of the defective inverter, especially under low voltage or short circuit conditions, will inevitably affect the photovoltaic DC simulation unit, resulting in inaccurate test data and failure to meet the test requirements. Second, in this test device, there is no RLC load device, and the photovoltaic inverter cannot be tested for anti-islanding protection. Third, the output end of the power grid simulator uses an isolation transformer with a voltage ratio of 1:1, which will cause the power grid simulator to be very large and have a large noise at low frequency output, which cannot meet the requirements of various application sites to bear weight and improve the test environment. 4. The photovoltaic DC simulator does not have isolation capability, and an isolation transformer must be added at the front end; the photovoltaic DC simulator uses a step-up transformer to test the overvoltage protection value of the photovoltaic inverter, but the overvoltage protection values ​​of different inverters are different, and the transformer's voltage gear is relatively fixed, which cannot finely detect the voltage adaptation range of the photovoltaic inverter. 5. When the capacity of the photovoltaic inverter under test increases, the photovoltaic DC simulation unit is required to have the corresponding capacity requirements, and the capacity of the power grid AC simulation unit must also meet the corresponding requirements before the corresponding test can be carried out. Utility Model Content

[0004] The utility model aims to solve the technical problems of inaccurate test data, test product performance affecting the state of test equipment, no RLC load device, large size and noise of power grid simulator, inability to finely detect the voltage adaptation range of photovoltaic inverter, and requirement for high capacity of DC and AC simulation units in existing photovoltaic inverter test devices, and to provide a photovoltaic inverter test device.

[0005] In order to achieve the above purpose, the technical solutions provided by the utility model are as follows:

[0006] A photovoltaic inverter test device, which is special in that it includes a power grid simulator, an RLC electronic load, a PV simulator, a detection module, a switch module, a power distribution module, a test product interface box, and a power and waveform recording module;

[0007] The grid simulator and the RLC electronic load are both bidirectional feed grid structures, with bidirectional power flow characteristics, which can not only output power but also feed the power of the photovoltaic inverter back to the grid, thus reducing power loss during testing;

[0008] The power distribution module is connected to the power grid simulator, the RLC electronic load, the PV simulator, and the power and waveform recording module respectively, and is used to provide power to each module respectively, and simultaneously receive power feedback from the power grid simulator and the RLC electronic load;

[0009] The switch module includes a grid-connected contactor, an off-grid contactor, and a single-phase or three-phase switching contactor; the test product interface box includes an AC three-phase output interface, an AC single-phase output interface, and a DC output interface;

[0010] The output end of the power grid simulator is connected to the input end of the grid-connected contactor, the output end of the RLC electronic load is connected to the input end of the off-grid contactor, and the output end of the off-grid contactor is connected to the output end of the grid-connected contactor; the output end of the grid-connected contactor is connected to the AC three-phase output interface;

[0011] The single-phase to three-phase switching contactor is used to connect the three phases ABC in parallel at the upper port of the AC three-phase output interface, and connect the C phase and the N phase to the AC single-phase output interface;

[0012] The output end of the PV simulator is connected to a DC output interface;

[0013] The AC three-phase output interface, AC single-phase output interface, and DC output interface 803 are used to connect to the photovoltaic inverter to be tested;

[0014] The detection module is used to collect the voltage and current on the AC side and the DC side of the photovoltaic inverter to be tested; the output end of the detection module is connected to the power and waveform recording module.

[0015] Further, the power grid simulator and the RLC electronic load have the same structure, including a three-phase rectifier / inverter module, a high-frequency bidirectional isolation module, and an inverter DC / AC module connected in sequence;

[0016] The PV simulator includes a three-phase rectifier / inverter module, a high-frequency bidirectional isolation module and a BUCK module. The PV simulator can perform stepless adjustment according to the voltage of the photovoltaic inverter to be tested, so as to accurately and quickly simulate PV characteristics and test the performance of the photovoltaic inverter;

[0017] The MOSFET field effect tubes in the three-phase rectifier / inverter module and the inverter DC / AC module are made of silicon carbide or gallium nitride materials, which can effectively increase the switching frequency of the power supply, make the control test more accurate, reduce the size of the power supply, and make integration more convenient. While ensuring the output, the power density of the power grid simulator is higher.

[0018] Further, the detection module includes four voltage sensors and four current sensors;

[0019] The power and waveform recording module includes a power analyzer and a waveform recorder;

[0020] The number of the detection module is one, wherein three voltage sensors and three current sensors are respectively used to measure the voltage and current of the three phases of the AC side of the photovoltaic inverter to be tested, and another voltage sensor and current sensor are respectively used to measure the voltage and current of the DC side of the photovoltaic inverter to be tested; the input end of the power analyzer is respectively connected to the output ends of the four voltage sensors and the four current sensors, so as to monitor whether the voltage and current of the DC side and the AC side meet the standards, and calculate various electric energy parameters; the input end of the waveform recorder is connected to the voltage output port and the current output port of the power analyzer, so as to obtain the test voltage waveform and current waveform of the photovoltaic inverter to be tested;

[0021] Alternatively, the number of the detection modules is two, and the three voltage sensors and the three current sensors in each detection module are respectively used to measure the voltage and current of the three phases on the AC side of the photovoltaic inverter to be tested, and the other voltage sensor and the current sensor are respectively used to measure the voltage and current on the DC side of the photovoltaic inverter to be tested; the input end of the power analyzer is respectively connected to the output ends of the four voltage sensors and the four current sensors in one detection module, so as to monitor whether the current and voltage on the DC side and the AC side meet the standards, and calculate various electric energy parameters; the input end of the waveform recorder is connected to the output ends of the four voltage sensors and the four current sensors in another detection module, so as to obtain the test voltage waveform and current waveform of the photovoltaic inverter to be tested.

[0022] Furthermore, it also includes a switch for connecting to an external industrial computer;

[0023] The switch is connected to the power grid simulator, RLC electronic load, PV simulator, grid-connected contactor, off-grid contactor, single-phase and three-phase switching contactor, photovoltaic inverter to be tested, power analyzer and waveform recorder through network cables to realize data exchange.

[0024] Further, the power distribution module includes a grid interface, a main power distribution switch, an AC power distribution switch, a PV power distribution switch, and an RLC power distribution switch;

[0025] The grid interface is used to connect to an external grid, and its output end is respectively connected to an AC distribution switch, a PV distribution switch, an RLC distribution switch, a power analyzer and a waveform recorder through a main distribution switch;

[0026] The other end of the AC distribution switch is connected to the input end of the power grid simulator, the other end of the RLC distribution switch is connected to the input end of the RLC electronic load, and the other end of the PV distribution switch is connected to the input end of the PV simulator.

[0027] Furthermore, it also includes N standard cabinets, N ≥ 2;

[0028] The power grid simulator, RLC electronic load, PV simulator, detection module, switch module, power distribution module, test product interface box, power and waveform recording module are respectively integrated in N standard cabinets.

[0029] Further, the N=2 includes a first standard cabinet and a second standard cabinet;

[0030] The power grid simulator, RLC electronic load, PV simulator, detection module, switch module, power distribution module, and test product interface box are integrated in the first standard cabinet; the power analyzer, waveform recorder, switch, power and waveform recording module are integrated in the second standard cabinet; the second standard cabinet is also used to integrate an external industrial computer.

[0031] Furthermore, the switch module also includes a switching knob, a grid-connected switch, an off-grid switch, a single-phase switch, and a three-phase switch;

[0032] The switch knob is used to switch between manual control and automatic control;

[0033] The grid-connected switch is connected to the grid-connected contactor and is used to control the closing and opening of the grid-connected contactor;

[0034] The off-grid switch is connected to the off-grid contactor and is used to control the closing and opening of the off-grid contactor;

[0035] The single-phase switch and the three-phase switch are connected to the single-phase and three-phase switching contactor to control the single-phase and three-phase switching contactor to achieve single-phase output or three-phase output;

[0036] The grid-connected switch, off-grid switch, single-phase switch and three-phase switch all use self-locking push button switches with lights. Furthermore, the power distribution module also includes a power indicator light and an output interface;

[0037] The detection module also includes an AC voltage measurement interface, an AC current measurement interface, a DC voltage measurement interface, a DC current measurement interface and an acquisition output interface;

[0038] The input ends of the AC voltage measurement interface and the AC current measurement interface are used to connect the output ends of the voltage sensor and the current sensor for measuring the AC side; the input ends of the DC voltage measurement interface and the DC current measurement interface are used to connect the output ends of the voltage sensor and the current sensor for measuring the DC side; the input end of the acquisition output interface is connected to the output ends of all voltage sensors and current sensors;

[0039] The first standard cabinet and the second standard cabinet are connected via an output interface of a power distribution module and an output end of a collection interface of a detection module.

[0040] Furthermore, the three-phase output interface, AC single-phase output interface, and DC output interface all use Anderson plugs;

[0041] The first standard cabinet and the second standard cabinet are both provided with floor-standing rollers below;

[0042] A foldable display is mounted on the second standard cabinet via a rotating shaft.

[0043] Compared with the prior art, the utility model has the following beneficial effects:

[0044] 1. Compared with the existing photovoltaic inverter test device, the test topology of the photovoltaic inverter test device provided by the utility model is more reasonable. The power grid simulator, RLC electronic load and PV simulator input terminals all draw power from the power grid interface to perform grid-connected and off-grid tests. During the test, even if the photovoltaic inverter to be tested is defective, it will not affect the test device. At the same time, the power grid simulator and the RLC electronic load are both set to a bidirectional feeding structure. During the test, the PV simulator supplies DC / AC power to the photovoltaic inverter to be tested through the DC output interface. The AC / DC output of the photovoltaic inverter to be tested feeds back electrical energy to the power grid simulator and the RLC electronic load through the AC three-phase output interface or the AC single-phase output interface. The power grid simulator and the RLC electronic load feed back energy to the power grid interface, which greatly reduces the power loss during the test.

[0045] 2. The utility model provides a photovoltaic inverter test device, which is provided with an RLC electronic load, and the input end of the RLC electronic load is connected to the output side of the power grid simulator and the output side of the photovoltaic inverter, and the output side is connected to the power grid interface. The RLC load can be controlled to start and the real RLC access state can be simulated, thereby realizing the inverter anti-islanding protection test.

[0046] 3. The utility model provides a photovoltaic inverter test device, in which the power grid simulator and the RLC electronic load both include a three-phase rectifier / inverter module, a high-frequency bidirectional isolation module and an inverter DC / AC module connected in sequence, and the PV simulator includes a three-phase rectifier / inverter module, a high-frequency bidirectional isolation module and a BUCK module; the MOSFET field-effect transistors in the three-phase rectifier / inverter module and the inverter DC / AC module adopt new materials such as silicon carbide or gallium nitride, which can effectively improve the switching frequency of the power supply, making the control test more accurate, and reducing the size of the power supply, making integration more convenient, while ensuring the output, so that the power density of the power grid simulator reaches 20kVA / 3U, the noise is lower, and the weight is as light as 35kg; at the same time, the output side adopts thyristors for full-bridge controllable inversion / rectification, which can output voltage and recover electrical energy.

[0047] 4. The utility model provides a photovoltaic inverter test device, in which the power grid simulator and the RLC electronic load have the same structure. The power grid simulator and the RLC electronic load can be connected in parallel to serve as a power grid simulator or as an RLC electronic load as a whole to achieve capacity expansion.

[0048] 5. The utility model provides a photovoltaic inverter test device, in which the power grid simulator, RLC electronic load and PV simulator all have the function of parallel expansion of the same model. The use of optical fiber communication between devices and output parallel connection can increase the capacity of the test equipment to meet the capacity expansion of the photovoltaic inverter to be tested.

[0049] 6. The utility model provides a photovoltaic inverter test device, which is integrated in multiple standard cabinets, greatly reducing the occupied area and weight of the test equipment, and can be used even in high-rise office buildings; at the same time, the test device adopts two modes: manual control and automatic control. In the automatic control, it can be started according to a prefabricated program to complete the test; in the manual control mode, a single module can be controlled and applied by a circuit breaker and a button, which greatly improves the flexibility of equipment application and makes the test device more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a system block diagram of an embodiment of a photovoltaic inverter testing device of the utility model;

[0051] Figure 2This is a schematic structural diagram of an embodiment of a photovoltaic inverter testing device of the utility model;

[0052] Figure 3 This is a schematic structural diagram of the lower right side of a cabinet in an embodiment of a photovoltaic inverter test device of the utility model;

[0053] Figure 4 A topological schematic diagram of a power grid simulator in an embodiment of a photovoltaic inverter test device of the utility model;

[0054] Figure 5 The topological diagram of a PV simulator in an embodiment of a photovoltaic inverter test device of the utility model is shown in FIG.

[0055] The specific reference numerals are as follows:

[0056] 1-first standard cabinet, 101-stationable roller, 102-wheel, 103-station, 104-knob, 105-pan head;

[0057] 2-Grid simulator; 3-RLC electronic load; 4-PV simulator;

[0058] 5-detection module, 501-AC voltage measurement interface, 502-AC current measurement interface, 503-DC voltage measurement interface, 504-DC current measurement interface, 505-collection output interface;

[0059] 6- switch module, 601- switch knob, 602- grid-connected switch, 603- off-grid switch, 604- single-phase switch, 605- three-phase switch, 606- grid-connected contactor, 607- off-grid contactor, 608- single-phase three-phase switching contactor;

[0060] 7-power distribution module, 701-grid interface, 702-power indicator light, 703-main power distribution switch, 704-AC power distribution switch, 705-PV power distribution switch, 706-RLC power distribution switch, 707-output interface;

[0061] 8-test product interface box, 801-AC three-phase output interface, 802-AC single-phase output interface, 803-DC output interface;

[0062] 9-the second standard cabinet; 10-power analyzer; 11-waveform recorder; 12-operating platform; 13-switch, 14-industrial computer; 15-storage box; 16-rotating shaft; 17-foldable display; 18-photovoltaic inverter to be tested. DETAILED DESCRIPTION

[0063] In order to make the advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] like Figure 1 As shown, a photovoltaic inverter test device includes a power grid simulator 2, an RLC electronic load 3, a PV simulator 4, a detection module 5, a switch module 6, a power distribution module 7, a test product interface box 8, a switch 13, a power analyzer 10, a waveform recorder 11 and an external industrial computer 14.

[0065] The power distribution module 7 includes a power grid interface 701, a power distribution main switch 703, an AC power distribution switch 704, a PV power distribution switch 705, and an RLC power distribution switch 706. The power distribution main switch 703 can control the power input of the test device, and in the event of an unexpected state, the switch can be used for emergency stop; the power grid interface 701 is used to connect to the external power grid, and its output end is respectively connected to the AC power distribution switch 704, the PV power distribution switch 705, the RLC power distribution switch 706, the industrial computer 14, the power analyzer 10, and the waveform recorder 11 through the power distribution main switch 703. The other end of the AC power distribution switch 704 is connected to the input end of the power grid simulator 2, the other end of the RLC power distribution switch 706 is connected to the input end of the RLC electronic load 3, and the other end of the PV power distribution switch 705 is connected to the input end of the PV simulator 4. The power grid interface 701 is used to provide power to the power grid simulator 2, the RLC electronic load 3, the PV simulator 4, the industrial computer 14, the power analyzer 10, and the waveform recorder 11.

[0066] The power grid simulator 2 is used to simulate the actual power grid environment, and the RLC electronic load 3 is used to accurately simulate the RLC characteristics by simulating the current characteristics of the RLC load. In the present utility model, the power grid simulator 2 and the RLC electronic load 3 are both bidirectional feeder structures, which can realize the bidirectional flow of energy, that is, the power grid simulator 2 and the RLC electronic load 3 can both output electrical energy and feed back the energy of the photovoltaic inverter 18 to be tested to the power grid to reduce the test energy loss. It is worth noting that the power grid simulator 2 and the RLC electronic load 3 are selected for use in different test conditions of the photovoltaic inverter 18 to be tested, that is, the two are not used at the same time under the same working condition. When the photovoltaic inverter 18 to be tested needs a load, the RLC electronic load 3 is controlled to be connected to simulate the RLC characteristics to provide a load. When the photovoltaic inverter 18 to be tested needs to simulate the power grid, the power grid simulator 2 is controlled to be connected to simulate the change test capability of the power grid.

[0067] Preferably, the power grid simulator 2 and the RLC electronic load 3 are configured to have the same structure, including a three-phase rectifier / inverter module, a high-frequency bidirectional isolation module, and an inverter DC / AC module connected in sequence. When the two structures are the same, the power grid simulator 2 and the RLC electronic load 3 can be connected in parallel to serve as a power grid simulator or as an RLC electronic load as a whole to achieve the purpose of capacity expansion. The MOSFET field effect tubes in the three-phase rectifier / inverter module and the inverter DC / AC module use new materials such as silicon carbide and gallium nitride, which ensures the output while making the power density of the power grid simulator higher.

[0068] The PV simulator 4 includes a three-phase rectifier / inverter module, a high-frequency bidirectional isolation module and a BUCK module. The PV simulator 4 can perform stepless regulation according to the voltage of the photovoltaic inverter 18 to be tested to accurately simulate PV characteristics and test the performance of the photovoltaic inverter.

[0069] The switch module 6 includes a grid-connected contactor 606, an off-grid contactor 607 and a single-phase three-phase switching contactor 608, which are used to cooperate with the test device to complete the execution of the system action. The test product interface box 8 includes an AC three-phase output interface 801, an AC single-phase output interface 802 and a DC output interface 803. The output end of the power grid simulator 2 is connected to the input end of the grid-connected contactor 606, the output end of the RLC electronic load 3 is connected to the input end of the off-grid contactor 607, and the output end of the off-grid contactor 607 is connected to the output end of the grid-connected contactor 606; the output end of the grid-connected contactor 606 is connected to the AC three-phase output interface 801. The single-phase three-phase switching contactor 608 is used to connect the ABC three-phases in parallel at the upper port of the AC three-phase output interface 801, and connect the C phase and the N phase to the AC single-phase output interface 802. The output end of the PV simulator 4 is directly connected to the DC output interface 803. The AC three-phase output interface 801 / AC single-phase output interface 802 and DC output interface 803 are used to connect to the photovoltaic inverter 18 to be tested. Preferably, the AC three-phase output interface 801, the AC single-phase output interface 802 and the DC output interface 803 all use Anderson plugs, which facilitates safe, reliable, convenient and fast plugging and unplugging of the photovoltaic inverter 18 to be tested.

[0070] The detection module 5 is used to collect the voltage and current on the input and output sides of the photovoltaic inverter 18 to be tested, and specifically includes four voltage sensors and four current sensors. Three of the voltage sensors and three of the current sensors are used to measure the power information of the AC three-phase output interface 801 of the photovoltaic inverter 18 to be tested, that is, the voltage and current of the three phases on the AC side; the other voltage sensor and current sensor are used to measure the power information of the DC output interface 803 of the photovoltaic inverter 18 to be tested, that is, the voltage and current on the DC side.

[0071] The power analyzer 10 is used to monitor whether the voltage and current on the DC side and the AC side meet the standards according to the voltage and current information measured by the voltage sensor and the current sensor, and calculate various electric energy parameters, such as power factor, electric energy, frequency, etc.; the waveform recorder 11 is used to obtain the test voltage waveform and current waveform of the photovoltaic inverter 18 to be tested according to the voltage and current information measured by the voltage sensor and the current sensor, and store and analyze them.

[0072] Both the power analyzer 10 and the waveform recorder 11 need to collect the voltage and current information measured by the voltage sensor and the current sensor. In order to save the number of voltage sensors and current sensors in the test equipment, in this embodiment, the input end of the power analyzer 10 is respectively connected to the output ends of four voltage sensors and four current sensors, and the input end of the waveform recorder 11 is connected to the voltage output port and the current output port of the power analyzer 10, that is, after the power analyzer 10 obtains the collected voltage and current information, it outputs it to the waveform recorder 11 through its own DA module to obtain the voltage and current information measured by the voltage sensor and the current sensor. In other embodiments of the utility model, two detection modules 5 can also be set, and the input end of the power analyzer 10 is respectively connected to the output ends of the four voltage sensors and four current sensors in one detection module 5, and the input end of the waveform recorder 11 is respectively connected to the output ends of the four voltage sensors and four current sensors in another detection module 5.

[0073] The industrial computer 14 has built-in system-level host software for the power grid simulator 2, the feedback electronic load 3, the PV simulator 4, the waveform recorder 11, and the power analyzer 10, which is used to control the parameters and operation of each module.

[0074] The switch 13 is connected to the power grid simulator 2, the RLC electronic load 3, the PV simulator 4, the industrial computer 14, the grid-connected contactor 606, the off-grid contactor 607, the single-phase and three-phase switching contactor 608, the photovoltaic inverter 18 to be tested, the power analyzer 10 and the waveform recorder 11 through network cables to realize data exchange; in other embodiments of the utility model, data exchange between modules can also be realized through other existing technologies.

[0075] The utility model is also provided with at least two standard cabinets for integrating the power grid simulator 2, RLC electronic load 3, PV simulator 4, detection module 5, switch module 6, power distribution module 7, test product interface box 8, industrial computer 14, power analyzer 10 and waveform recorder 11 in multiple standard cabinets, which can greatly reduce the occupied area and weight of the test device, and can also be used in high-rise office buildings. The present embodiment includes a first standard cabinet 1 and a second standard cabinet 9, both of which adopt 19-inch 26U standard cabinets; the power grid simulator 2, RLC electronic load 3, PV simulator 4, detection module 5, switch module 6, power distribution module 7, test product interface box 8 are integrated in the first standard cabinet 1, and the power analyzer 10, waveform recorder 11, switch 13, industrial computer 14 are integrated in the second standard cabinet 9.

[0076] A stationary roller 101 is provided below the first standard cabinet 1 and the second standard cabinet 9, which can be manually adjusted to two modes: mobile and stationary. The stationary roller 101 adopts the structural form of existing bolts and pan-tilt heads, including wheels 102, a station 103, a knob 104 and a pan-tilt head 105. The difference is that the material of the station in the existing structure is rubber, while the station 103 in the utility model is made of conductive material in the middle and rubber material on the outside, so that the equipment is reliably grounded while preventing slipping, ensuring the safety of the test. By turning the knob 104 in the stationary mode through the wheel 102, the station 103 falls to the ground, and the cabinet is slightly raised. At this time, the wheel 102 and the pan-tilt head 105 are fixed and gradually rise, and the equipment is thus fixed. The test device is immovable and reliably grounded, protecting the test personnel and the test device. In mobile mode, the station 103 is retracted, the cabinet is slightly lowered, and the wheels 102 are reliably grounded. The first standard cabinet 1 and the second standard cabinet 9 can be moved to a suitable test area by the wheels 102 after the moving angle can be freely switched through the pan / tilt 105. After reaching the position, the equipment station is reliably guaranteed to be safe. At the same time, a foldable display 17 is installed on the side wall end face of the second standard cabinet 9 through a rotating shaft 16, and the cables of the industrial computer 14 in the second standard cabinet 9 are connected to the foldable display 17 through the internal space of the rotating shaft 16. The display can be folded when not in use to reduce the floor space of the test device. A storage box 15 is also provided in the second standard cabinet 9 for storing accessories and consumables. At the same time, the interface cables and acquisition interface cables between cabinets can be placed in the storage module 15 during the movement of the cabinet, and the detection cables of the detection module can also be placed in the storage module 15. An operating platform 12 is also provided on the panel of the second standard cabinet 9 . The operating platform 12 has a built-in keyboard connected to an industrial computer 14 for operating the upper computer software in the industrial computer 14 through the operating platform 12 to control the parameters and operation of each module.

[0077] The detection module 5 also includes an AC voltage measurement interface 501, an AC current measurement interface 502, a DC voltage measurement interface 503, a DC current measurement interface 504, and a collection output interface 505 arranged on the side of the first standard cabinet 1. The input ends of the AC voltage measurement interface 501 and the AC current measurement interface 502 are used to connect the output ends of the voltage sensor and the current sensor for measuring the voltage and current on the AC side, and are used to output the voltage and current of the three phases on the AC side of the photovoltaic inverter 18 to be tested; the input ends of the DC voltage measurement interface 503 and the DC current measurement interface 504 are used to connect the output ends of the voltage sensor and the current sensor for measuring the voltage and current on the DC side, and are used to output the voltage and current on the DC side of the photovoltaic inverter 18 to be tested, so as to facilitate external manual collection. The input end of the collection output interface 505 is connected to the output ends of all voltage sensors and current sensors, and is used to transmit the corresponding voltage and current data to the power analyzer 10 in the second standard cabinet 9 through the collection output interface 505.

[0078] The power distribution module 7 also includes a power indicator light 702 arranged on the panel of the first standard cabinet 1 and an output interface 707 arranged on the side of the first standard cabinet 1. The power indicator light 702 is used to display the working status of the power grid; the output interface 707 is connected to the main power distribution switch 703, and is used to supply power to the power analyzer 10, the waveform recorder 11, the switch 13 and the industrial computer 14 in the second standard cabinet 9 through the output interface 707.

[0079] At the same time, the switch module 6 also includes a switching knob 601, a grid-connected switch 602, an off-grid switch 603, a single-phase switch 604, and a three-phase switch 605 arranged on the panel of the first standard cabinet 1. The switching knob 601 is used to switch the test device to an automatic control mode or a manual control mode. In the automatic control, it can be started according to the program in the upper computer software to complete the test; in the manual control mode, a single module can be controlled and applied through a circuit breaker and a button, which greatly improves the flexibility of the equipment application. The grid-connected switch 602 is connected to the grid-connected contactor 606 to control the closing and opening of the grid-connected contactor 606; the off-grid switch 603 is connected to the off-grid contactor 607 to control the closing and opening of the off-grid contactor 607; the single-phase switch 604 and the three-phase switch 605 are respectively connected to the single-phase three-phase switching contactor 608 to control the single-phase three-phase switching contactor 608 to achieve single-phase output or three-phase output. In this embodiment, the grid-connected switch 602, the off-grid switch 603, the single-phase switch 604 and the three-phase switch 605 are all self-locking push button switches with lights.

[0080] The working process of the photovoltaic inverter test device provided by the utility model is as follows: connect to the external power grid through the power grid interface 701, then the power indicator light 702 lights up, close the main power distribution switch 703, and start the industrial computer 14, the power analyzer 10, the waveform recorder 11, and the switch 13. Close the AC power distribution switch 704, the PV power distribution switch 705, and the RLC power distribution switch 706 in sequence, and the power grid simulator 2, the RLC electronic load 3, and the PV simulator 4 enter the standby state.

[0081] In manual control, the switch knob 601 is rotated to the manual mode, and the PV simulator operation panel 402 is manually adjusted to set the test voltage, current, power and other parameters, and the PV simulation output is performed through the first OUT button 403 to provide DC power for the photovoltaic inverter 18 to be tested. The grid simulator operation panel 202 is manually adjusted to set the test voltage, frequency, phase and other parameters, and the grid simulation output is performed through the second OUT button 203 to provide an AC side test environment for the photovoltaic inverter 18 to be tested. The RLC electronic load operation panel 302 is manually adjusted to set the connection mode and value of the test R, L, and C, and the RLC load simulation is performed through the third OUT button 303. When the photovoltaic inverter 18 to be tested is started, the grid-connected switch 602 is pressed, and the grid-connected contactor 606 is closed, and the button indicator light is on. At this time, the photovoltaic inverter 18 to be tested feeds the grid to generate electricity, and the electric energy is fed back to the grid interface 701 through the grid simulator 2, reducing the power loss in the test state, and completing the grid-connected test of the photovoltaic inverter 18 to be tested. When testing off-grid, press the off-grid switch 603, the off-grid contactor 607 is closed, the button indicator light is on, and the RLC electronic load 3 is put into use; press the grid switch 602, the grid contactor 606 is disconnected, the button indicator light is off, and the AC side of the photovoltaic inverter 18 to be tested is completely output to the RLC electronic load 3. The third operation panel 302 in the RLC electronic load 3 can control the R / L / C connection mode and related parameters in the RLC electronic load 3 to truly simulate the RLC load state. The test electric energy is fed back to the grid interface 701 through the RLC electronic load 3 to complete the off-grid test of the photovoltaic inverter 18 to be tested. During the test, the voltage sensor and current sensor in the detection module 5 collect the electric energy information of the DC side input and AC side output of the photovoltaic inverter 18 to be tested, and the collected information is transmitted to the power analyzer 10 through the collection output interface 505. The power analyzer 10 can transmit the collected information to the waveform recorder 11 through its own DA module. The user starts the device by pressing the power button of the power analyzer 11, and adjusts the displayed information through the power analyzer operation panel, and can observe the test information related to the photovoltaic inverter 18 to be tested; at the same time, the user starts the device by pressing the power button of the waveform recorder, and adjusts the displayed information through the waveform recorder operation panel, and can observe the relevant test waveforms, and can store and analyze the relevant waveforms. Press the switch start button and the industrial computer power button to start the switch 13 and the industrial computer 14.

[0082] When in automatic control, you first need to stop the output of the test device. You can stop the output by controlling the host computer software or press the PV simulator power button 401, the power button 201 of the power grid simulator, and the power button 301 of the feedback RLC electronic load to shut down the device output. Turn the switch knob 601 to the automatic mode. At this time, operate the host computer software to match the relevant program to complete the fully automated test, that is, automatically perform the preset program test through the host computer software, automatically complete the test content, record the test data, store the waveform during the test, and generate a test report, which greatly improves the test efficiency. After the test is completed, the output of the test device will be automatically stopped to ensure the safety of the test.

[0083] After the test of the current photovoltaic inverter 18 to be tested is completed, it is necessary to replace the photovoltaic inverter 18 to be tested to continue the test. At this time, the replacement of the photovoltaic inverter to be tested can be quickly completed through the Anderson plug in the test product interface box 8, and the equipment connection can be quickly completed under the premise of ensuring safety.

[0084] The above description is only used to illustrate the technical solution of the utility model, rather than to limit it. For ordinary professional and technical personnel in the field, the specific technical solution recorded in the above embodiment can be modified, or some of the technical features therein can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution protected by the utility model.

Claims

1. A photovoltaic inverter testing device, characterized in that: It includes a power grid simulator (2), an RLC electronic load (3), a PV simulator (4), a detection module (5), a switch module (6), a power distribution module (7), a test product interface box (8), and a power and waveform recording module; The power grid simulator (2) and the RLC electronic load (3) are both bidirectional feed grid structures; The power distribution module (7) is respectively connected to the power grid simulator (2), the RLC electronic load (3), the PV simulator (4), and the power and waveform recording module, and is used to provide electric energy to each module respectively, and simultaneously receive electric energy fed back by the power grid simulator (2) and the RLC electronic load (3); The switch module (6) includes a grid-connected contactor (606), an off-grid contactor (607) and a single-phase to three-phase switching contactor (608); the test product interface box (8) includes an AC three-phase output interface (801), an AC single-phase output interface (802) and a DC output interface (803); The output end of the power grid simulator (2) is connected to the input end of the grid-connected contactor (606), the output end of the RLC electronic load (3) is connected to the input end of the off-grid contactor (607), and the output end of the off-grid contactor (607) is connected in parallel to the output end of the grid-connected contactor (606); the output end of the grid-connected contactor (606) is connected to the AC three-phase output interface (801); The single-phase to three-phase switching contactor (608) is used to connect the three phases ABC in parallel at the upper port of the AC three-phase output interface (801), and to connect the C phase and the N phase to the AC single-phase output interface (802); The output end of the PV simulator (4) is connected to a DC output interface (803); The AC three-phase output interface (801), the AC single-phase output interface (802), and the DC output interface (803) are used to connect to the photovoltaic inverter (18) to be tested; The detection module (5) is used to collect the voltage and current on the AC side and the DC side of the photovoltaic inverter (18) to be tested; the output end of the detection module (5) is connected to the power and waveform recording module.

2. A photovoltaic inverter testing device according to claim 1, characterized in that: The power grid simulator (2) and the RLC electronic load (3) have the same structure, including a three-phase rectifier / inverter module, a high-frequency bidirectional isolation module and an inverter DC / AC module connected in sequence; The PV simulator (4) comprises a three-phase rectification / inversion module, a high-frequency bidirectional isolation module and a BUCK module; The MOSFET field effect tubes in the three-phase rectification / inversion module and the inverter DC / AC module are made of silicon carbide or gallium nitride.

3. A photovoltaic inverter testing device according to claim 1 or 2, characterized in that: The detection module (5) comprises four voltage sensors and four current sensors; The power and waveform recording module comprises a power analyzer (10) and a waveform recorder (11); The number of the detection module (5) is one, wherein three voltage sensors and three current sensors are respectively used to measure the voltage and current of the three phases of the AC side of the photovoltaic inverter (18) to be tested, and another voltage sensor and current sensor are respectively used to measure the voltage and current of the DC side of the photovoltaic inverter (18) to be tested; The input end of the power analyzer (10) is respectively connected to the output ends of four voltage sensors and four current sensors, and is used to monitor whether the voltage and current on the DC side and the AC side meet the standards, and calculate various electric energy parameters; the input end of the waveform recorder (11) is connected to the voltage output port and the current output port of the power analyzer (10), and is used to obtain the test voltage waveform and current waveform of the photovoltaic inverter (18) to be tested; or, the number of the detection modules (5) is two, and the three voltage sensors and the three current sensors in each detection module (5) are respectively used to measure the three voltage sensors and the three current sensors on the AC side of the photovoltaic inverter (18) to be tested. The power analyzer (10) is connected to the output ends of four voltage sensors and four current sensors in a detection module (5) to monitor whether the current and voltage on the DC side and the AC side meet the standards and calculate various electric energy parameters; the waveform recorder (11) is connected to the output ends of four voltage sensors and four current sensors in another detection module (5) to obtain the test voltage waveform and current waveform of the photovoltaic inverter (18) to be tested.

4. A photovoltaic inverter testing device according to claim 3, characterized in that: It also includes a switch (13) for connecting to an external industrial computer (14); The switch (13) is respectively connected to the power grid simulator (2), the RLC electronic load (3), the PV simulator (4), the grid-connected contactor (606), the off-grid contactor (607), the single-phase and three-phase switching contactor (608), the photovoltaic inverter to be tested (18), the power analyzer (10) and the waveform recorder (11) through network cables to realize data exchange.

5. A photovoltaic inverter testing device according to claim 4, characterized in that: The power distribution module (7) comprises a power grid interface (701), a main power distribution switch (703), an AC power distribution switch (704), a PV power distribution switch (705) and an RLC power distribution switch (706); The power grid interface (701) is used to connect to an external power grid, and its output end is respectively connected to an AC power distribution switch (704), a PV power distribution switch (705), an RLC power distribution switch (706), a power analyzer (10) and a waveform recorder (11) through a main power distribution switch (703); The other end of the AC distribution switch (704) is connected to the input end of the power grid simulator (2), the other end of the RLC distribution switch (706) is connected to the input end of the RLC electronic load (3), and the other end of the PV distribution switch (705) is connected to the input end of the PV simulator (4).

6. A photovoltaic inverter testing device according to claim 5, characterized in that: It also includes N standard cabinets, N ≥ 2; The power grid simulator (2), the RLC electronic load (3), the PV simulator (4), the detection module (5), the switch module (6), the power distribution module (7), the test product interface box (8), and the power and waveform recording module are respectively integrated in N standard cabinets.

7. A photovoltaic inverter testing device according to claim 6, characterized in that: The N=2 includes a first standard cabinet (1) and a second standard cabinet (9); The power grid simulator (2), RLC electronic load (3), PV simulator (4), detection module (5), switch module (6), power distribution module (7), and test product interface box (8) are integrated in a first standard cabinet (1); the power analyzer (10), waveform recorder (11), switch (13), and power and waveform recording module are integrated in a second standard cabinet (9); the second standard cabinet (9) is also used to integrate an external industrial computer (14).

8. A photovoltaic inverter testing device according to claim 7, characterized in that: The switch module (6) further comprises a switching knob (601), a grid-connected switch (602), an off-grid switch (603), a single-phase switch (604), and a three-phase switch (605); The switch knob (601) is used to switch between manual control and automatic control; The grid-connected switch (602) is connected to the grid-connected contactor (606) and is used to control the closing and opening of the grid-connected contactor (606); The off-grid switch (603) is connected to the off-grid contactor (607) and is used to control the closing and opening of the off-grid contactor (607); The single-phase switch (604) and the three-phase switch (605) are connected to the single-phase and three-phase switching contactor (608) to control the single-phase and three-phase switching contactor (608) to achieve single-phase output or three-phase output; The grid-connected switch (602), off-grid switch (603), single-phase switch (604) and three-phase switch (605) are all self-locking push button switches with lights.

9. A photovoltaic inverter testing device according to claim 8, characterized in that: The power distribution module (7) further comprises a power indicator light (702) and an output interface (707); The detection module (5) further comprises an AC voltage measurement interface (501), an AC current measurement interface (502), a DC voltage measurement interface (503), a DC current measurement interface (504) and a collection output interface (505); The input ends of the AC voltage measurement interface (501) and the AC current measurement interface (502) are used to connect the output ends of the voltage sensor and the current sensor for measuring the AC side; The input ends of the DC voltage measurement interface (503) and the DC current measurement interface (504) are used to connect the output ends of the voltage sensor and the current sensor for measuring the DC side; the input end of the acquisition output interface (505) is connected to the output ends of all the voltage sensors and the current sensors; The first standard cabinet (1) and the second standard cabinet (9) are connected via the output interface (707) of the power distribution module (7) and the output end of the collection output interface (505) of the detection module (5).

10. A photovoltaic inverter testing device according to claim 9, characterized in that: The three-phase output interface (801), AC single-phase output interface (802), and DC output interface (803) all use Anderson plugs; Floor-mounted rollers (101) are provided below the first standard cabinet (1) and the second standard cabinet (9); A foldable display (17) is mounted on the second standard cabinet (9) via a rotating shaft (16).

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