Real-time simulation | EasyGo energy storage inverter in-the-loop test solution

smls_小森

Real-time simulation | EasyGo energy storage inverter in-the-loop test solution [Copy link]

1. Energy Storage Inverter

Energy storage inverter PCS (Power Conversion System) is a device that stores electrical energy in batteries and converts it into AC power when needed. Currently, energy storage inverters play an important role in the following application scenarios:

• Home and commercial energy storage systems: Energy storage inverters can store electricity generated by solar panels or wind turbines for use at night or when energy generation is low. Such systems can help homes and commercial buildings reduce their dependence on the grid, reduce energy costs, and provide backup power capabilities.
• Microgrid system: Energy storage inverters play a key role in microgrid systems. A microgrid system is a small power system that is independent of the main grid and can be powered by a variety of energy sources (such as solar energy, wind energy, diesel generators, etc.). Energy storage inverters can balance energy supply and demand in microgrid systems, provide stable power output, and achieve seamless switching to the main grid.
• Electric vehicle charging stations: Energy storage inverters can be used in electric vehicle charging stations to store grid power in batteries and convert it into DC power to charge electric vehicles when needed. This application can balance grid loads, improve charging efficiency, and enable fast charging of electric vehicles.
• Sudden power demand scenarios: Energy storage inverters can be used to cope with sudden power demand scenarios, such as natural disasters, power outages, etc. It can provide temporary backup power to ensure the normal operation of key equipment and the continuity of life and production.

Energy storage inverters have broad application prospects in renewable energy utilization, energy storage, and reliability of power supply, and can play an important role in various scenarios.

2. Energy storage inverter system grid access detection

Energy storage inverter system grid access testing is an important step to ensure that the energy storage system is safely and reliably connected to the power grid. This test is usually conducted by power companies or relevant regulatory agencies to ensure that the energy storage system meets the prescribed technical standards and safety requirements.

The controller in-the-loop test of the energy storage inverter system is an important step to ensure that the system can work normally in the actual operating environment. The in-the-loop test solution usually includes the following aspects:

• Compliance verification: Test whether the PCS controller complies with relevant standards and specifications, including safety standards, electrical standards, communication protocols, etc.
• Functional test: Test whether the various functions of the PCS controller are working properly, including the measurement and control of input and output voltage and current, the ability to connect and disconnect the grid, etc.
• Power quality detection: Test the impact of the PCS controller on power quality, including detecting its impact on voltage waveform, frequency, harmonics, etc., and ensure its normal operation under various power quality issues.
• Operation monitoring: Monitor and record the PCS controller over a long period of time in the actual operating environment to evaluate its performance and reliability in actual applications and to identify and resolve potential problems in a timely manner.
• Stability assessment: By simulating the real operating environment, the stability and reliability of the PCS controller under different workloads and grid conditions are tested. This includes testing its responsiveness and stability under high load, low load, sudden load, etc.

3. PCS Controller In-Loop Test

By conducting in-loop testing of the PCS controller, it can be ensured that it can work safely and reliably in actual applications and meet the needs of various application scenarios. Based on the characteristics of semi-physical simulation that supports the construction of any topology model and is highly accurate, the use of HIL semi-physical hardware-in-the-loop for grid-connected testing of energy storage systems has gradually become a mainstream trend. EasyGo uses an FPGA-based HIL real-time simulator to help enterprise engineers conduct the following semi-physical simulation research and testing of energy storage converters:

• Research on the application of various energy storage converter topologies
• Stability and reliability test of energy storage converter under different load and grid conditions
• Energy storage converter on/off-grid switching, low voltage ride-through and other tests
• Performance verification of new control algorithms

The above figure shows the multi-machine parallel topology structure of energy storage converters, in which a single energy storage converter adopts the ANPC three-level topology structure, and four energy storage converters are connected in parallel.

4. Solutions based on EasyGo

▍Real-time simulation solution for energy storage converter based on NetBox 5604

Based on the super FPGA computing accuracy of NetBox 5604, the power electronic topology structure such as energy storage converter can be run on FPGA, and the rich IO interface can be used to realize multi-machine parallel testing of energy storage converter.

▍Real-time simulation actual test system diagram

• Test content: The real-time simulation platform can perform some standard tests on the energy storage inverter, such as grid-connected and off-grid switching test, charge-discharge switching test, low voltage ride-through test, etc.; at the same time, it can also effectively avoid the "machine explosion" phenomenon caused by the controller, providing enterprises with an efficient and safe testing platform.
• Power control detection: According to the test standard requirements of the "Technical Regulations for Energy Storage Inverter Testing", when the energy storage inverter is in normal grid-connected mode, set different active and reactive power instructions to observe whether its power changes are accurate and quickly track the active and reactive instructions.
• Grid-connected and off-grid switching detection: According to the test standard requirements of the "Technical Regulations for Energy Storage Inverter Testing", in order to ensure that the energy storage inverter can normally switch between grid-connected and off-grid, set the load power to 100% of the rated power of the energy storage inverter under test, and adjust the energy storage inverter to work under the grid-connected rated power charging operation condition. After the energy storage inverter runs stably, disconnect the grid-connected switch and observe the voltage and current waveforms of the energy storage inverter.
• Charge and discharge conversion time detection: According to the test standard requirements of the "Technical Regulations for Energy Storage Inverter Testing", it is necessary to measure the minimum time interval t1 of the energy storage inverter switching from 90% of the rated charging power state to 90% of the rated discharge power state, and the minimum time interval t2 from 90% of the rated discharge power state to 90% of the rated charging power state, and then calculate the average charge and discharge switching minimum time, which should be less than 100ms.
• Low voltage ride-through capability test: According to the test standard requirements of the "Technical Regulations for Energy Storage Inverter Testing", in order to ensure that the energy storage inverter can still operate stably and safely when the grid voltage fluctuates, the grid-side voltage is set to drop by 0.0pu, 0.2pu, 0.5pu, 0.75pu, and 0.85pu respectively, and the response capability under different instantaneous voltage drop conditions is tested.

Thank you for your attention, and welcome interested engineers to communicate with us!