Photovoltaic inverter parameter testing method based on field actual measurement and hardware-in-loop simulation

Abstract

The invention discloses a photovoltaic inverter parameter testing method based on field actual measurement and hardware-in-the-loop simulation, and belongs to the technical field of inverter parameter testing. The method aims at solving the problem that when an existing photovoltaic power generation unit is tested, data of fault ride-through dead zones of a photovoltaic inverter cannot be obtained, and therefore the parameter identification accuracy of an inverter controller is poor. A photovoltaic array and a photovoltaic inverter are connected to a field test device, an active power control test, a reactive power control test, an alternating current side small disturbance test, an alternating current side large disturbance test and an alternating current side frequency disturbance test are carried out on the photovoltaic inverter, corresponding test data are obtained, a simulation model is established, and a simulation result is obtained. The simulation model is connected with an inverter control system through a physical interface and used for achieving disturbance of different degrees on the alternating current side, and corresponding test data are obtained; and performing inverter control parameter identification by using the experimental data. The method is mainly used for identifying the control parameters of the photovoltaic inverter.

Description

Technical Field

[0001] The invention belongs to the technical field of inverter parameter testing. Background Art

[0002] The simulation model that reflects the actual grid-connected operation characteristics of photovoltaic inverters is the basis and key to achieving accurate simulation of high-proportion new energy systems. The existing photovoltaic inverter transient model parameter identification is based on field experiments. Against the background of the increasing proportion of power electronic equipment, higher requirements are placed on the accuracy of photovoltaic inverter models.

[0003] The existing parameters testing of electromechanical transient models cannot cover all operating conditions. Taking low voltage ride-through as an example, the photovoltaic inverter is tested under 20 operating conditions, including different voltage drop levels, different fault types and different initial operating powers. It can perform parameter identification and model verification on the single fault ride-through model within a specific voltage range, and can obtain the converter capacity and overcurrent capacity of the new energy unit. However, it is difficult to carry out a large number of field tests, resulting in a relatively insufficient coverage of the test conditions. It is impossible to obtain data on the dead zone of the photovoltaic inverter fault ride-through, and it is impossible to explain the adaptability of the model parameters under different initial power states.

[0004] Nowadays, photovoltaic power generation units must undergo low / high penetration sampling detection of power tests before they are connected to the grid. However, due to the large differences between the grid conditions such as the on-site grid structure and the system short-circuit ratio and the power supply during the on-site test, the on-site photovoltaic power generation units need to modify their control parameters to adapt to the specific grid to obtain the best operating state; at the same time, in order to improve the consumption of new energy in the DC near-zone, various manufacturers have carried out single-machine control parameter optimization work on photovoltaic inverters connected to the DC near-zone, which has led to the diversification and differentiation of the versions of the photovoltaic power generation unit controllers in operation on site, resulting in a large difference between the electromechanical transient model adjusted according to the power level test and the transient characteristics of the photovoltaic power generation unit operating in the new energy power station, and it is necessary to re-conduct on-site parameter testing or obtain accurate external characteristic parameters of the photovoltaic inverter based on other means. Summary of the invention

[0005] The present invention aims to solve the problem that when the existing photovoltaic power generation unit is tested, the data of the photovoltaic inverter fault crossing the dead zone cannot be obtained, resulting in poor accuracy in inverter controller parameter identification. A photovoltaic inverter parameter testing method based on field measurement and hardware-in-the-loop simulation is provided.

[0006] The photovoltaic inverter parameter testing method based on field measurement and hardware-in-the-loop simulation of the present invention comprises:

[0007] Step 1, connecting the photovoltaic array and the photovoltaic inverter to the field test device, performing active control test, reactive control test, AC side small disturbance test, AC side large disturbance test and AC side frequency disturbance test on the photovoltaic inverter, and obtaining active control test data, reactive control test data, AC side small disturbance test data, AC side large disturbance test data and AC side frequency disturbance test data;

[0008] Step 2: Establish a simulation model, connect the simulation model to the inverter control system through a physical interface, and implement different degrees of disturbance on the AC side to obtain AC side voltage drop disturbance test data;

[0009] Step three: using the active power control test data, reactive power control test data, AC side small disturbance test data, AC side large disturbance test data, AC side frequency disturbance test data and AC side voltage drop disturbance test data to identify the control parameters of the inverter.

[0010] Further, in the present invention, in step 1, the field test device includes a step-up transformer, a voltage drop generating device and a data acquisition device;

[0011] The photovoltaic array is connected to a step-up transformer via a photovoltaic inverter, and the data acquisition device acquires current and voltage data passing through the photovoltaic inverter;

[0012] The step-up transformer is used to step up and transform the voltage passing through the photovoltaic inverter and then connect it to the voltage drop generating device. The voltage drop generating device is used to generate voltage drop disturbance and frequency disturbance, thereby realizing active control test, reactive power control test, AC side small disturbance test, AC side large disturbance test and AC side frequency disturbance test.

[0013] Further, in the present invention, in step 2, the simulation model includes: a power grid disturbance generation module, a power grid disturbance generation module, a transformer module, a photovoltaic inverter power loop model, a photovoltaic array model and an I / O physical address module;

[0014] The controller of the photovoltaic inverter is connected to the photovoltaic inverter power loop model through a physical interface and an I / O physical address module;

[0015] The grid disturbance generation module is used to generate disturbance changes in the AC layer load, and the transformer module is used to transform the voltage output by the photovoltaic array model through the photovoltaic inverter power loop model;

[0016] The photovoltaic inverter power loop model is used to receive a photovoltaic inverter controller control signal and feed back the voltage and current signals of the line to the photovoltaic inverter controller.

[0017] The parameter testing method described in the present invention is mainly based on field testing and supplemented by hardware-in-the-loop testing. Photovoltaic inverter model parameter identification and model verification are carried out based on a combination of field test data and controller hardware-in-the-loop simulation data. The relationship between the two testing methods is two-way verification and mutual complementation, and together form a complete model parameter testing method for photovoltaic inverters. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of the method of the present invention;

[0019] Figure 2 This is the schematic diagram of the field test system;

[0020] Figure 3 This is the schematic diagram of hardware simulation in the loop test. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0022] Specific implementation method 1: refer to Figures 1 to 3 Specifically describing this embodiment, the photovoltaic inverter parameter testing method based on field measurement and hardware-in-the-loop simulation described in this embodiment includes:

[0023] Step 1: Connect the photovoltaic array 101 and the photovoltaic inverter 102 to the field test device, perform active control test, reactive control test, AC side small disturbance test, AC side large disturbance test and AC side frequency disturbance test on the photovoltaic inverter 102, and obtain active control test data, reactive control test data, AC side small disturbance test data, AC side large disturbance test data and AC side frequency disturbance test data;

[0024] Step 2: Establish a simulation model, connect the simulation model to the inverter control system through a physical interface, and implement different degrees of disturbance on the AC side to obtain AC side voltage drop disturbance test data;

[0025] Step three: using the active power control test data, reactive power control test data, AC side small disturbance test data, AC side large disturbance test data, AC side frequency disturbance test data and AC side voltage drop disturbance test data to identify the control parameters of the inverter.

[0026] Further, in the present invention, in step 1, the field test device includes a step-up transformer 104, a voltage drop generating device 105 and a data acquisition device 103;

[0027] The photovoltaic array 101 is connected to the step-up transformer 104 via the photovoltaic inverter 102, and the data acquisition device 103 acquires the current and voltage data passing through the photovoltaic inverter 102;

[0028] The step-up transformer 104 is used to step up and transform the voltage passing through the photovoltaic inverter 102 and then connect it to the voltage drop generating device 105. The voltage drop generating device 105 is used to generate voltage drop disturbance and frequency disturbance, thereby realizing active control test, reactive power control test, AC side small disturbance test, AC side large disturbance test and AC side frequency disturbance test.

[0029] Further, in the present invention, in step 2, the simulation model includes: a power grid disturbance generation module 201, a power grid disturbance generation module 201, a transformer module 202, a photovoltaic inverter power loop model 204, a photovoltaic array model 203 and an I / O physical address module 205;

[0030] The controller of the photovoltaic inverter 102 is connected to the photovoltaic inverter power loop model 204 via a physical interface and an I / O physical address module 205;

[0031] The grid disturbance generation module 201 is used to generate disturbance changes of the AC layer load, and the transformer module 202 is used to transform the voltage output by the photovoltaic array model 203 through the photovoltaic inverter power loop model 204;

[0032] The photovoltaic inverter power loop model 204 is used to receive control signals from the photovoltaic inverter 102 controller and feed back voltage and current signals of the line to the photovoltaic inverter 102 controller.

[0033] In order to obtain the model parameters of the photovoltaic inverter 102, the photovoltaic inverter 102 field test items are carried out, including: active control test, reactive control test, AC side small disturbance test, AC side large disturbance test and AC side frequency disturbance test. Among them, the active control test data is used to identify the parameters of the active fixed value control module, the reactive control test data is used to identify the parameters of the reactive fixed value control module, the AC side small disturbance test data is used to identify the control parameters of the active / reactive control module in the steady-state operation control module, the AC side large disturbance test data is used to identify the fault protection module parameters, and the AC side frequency disturbance test data is used to identify the primary frequency modulation parameters.

[0034] The semi-physical test described in the present invention may also be carried out as a field test simulation experiment to verify and check the experimental data obtained from the field experiment.

[0035] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A photovoltaic inverter parameter testing method based on field measurement and hardware-in-the-loop simulation, characterized in that: include: Step 1: Connecting the photovoltaic array (101) to a field test device via a photovoltaic inverter (102), performing an active control test, a reactive control test, an AC side small disturbance test, an AC side large disturbance test, and an AC side frequency disturbance test on the photovoltaic inverter (102), and obtaining active control test data, reactive control test data, AC side small disturbance test data, AC side large disturbance test data, and AC side frequency disturbance test data; Step 2: Establish a simulation model, connect the simulation model to the inverter control system through a physical interface, and implement different degrees of disturbance on the AC side to obtain AC side voltage drop disturbance test data; Step three: using the active power control test data, reactive power control test data, AC side small disturbance test data, AC side large disturbance test data, AC side frequency disturbance test data and AC side voltage drop disturbance test data to identify the control parameters of the inverter.

2. The photovoltaic inverter parameter testing method based on field measurement and hardware-in-the-loop simulation according to claim 1 is characterized in that: In step 1, the on-site testing device includes a step-up transformer (104), a voltage drop generating device (105) and a data acquisition device (103); The photovoltaic array (101) is connected to a step-up transformer (104) via a photovoltaic inverter (102), and the data acquisition device (103) acquires current and voltage data passing through the photovoltaic inverter (102); The step-up transformer (104) is used to step up and transform the voltage passed through the photovoltaic inverter (102) and then connect it to the voltage drop generating device (105). The voltage drop generating device (105) is used to generate voltage drop disturbance and frequency disturbance, thereby realizing active control test, reactive power control test, AC side small disturbance test, AC side voltage disturbance test and AC side frequency disturbance test.

3. The photovoltaic inverter parameter testing method based on field measurement and hardware-in-the-loop simulation according to claim 1 or 2, characterized in that: In step 2, the simulation model includes: a power grid disturbance generation module 201, a transformer module (202), a photovoltaic inverter power loop model (204), a photovoltaic array model (203) and an I / O physical address module (205); The controller of the photovoltaic inverter (102) is connected to the photovoltaic inverter power loop model (204) via a physical interface and an I / O physical address module (205); The power grid disturbance generation module 201 is used to generate disturbance changes of the AC layer load, and the transformer module (202) is used to transform the voltage output by the photovoltaic array model (203) through the photovoltaic inverter power circuit model (204); The photovoltaic inverter power loop model (204) is used to receive a control signal from a photovoltaic inverter (102) controller and feed back voltage and current signals of the line to the photovoltaic inverter (102) controller.

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