The PAS 5000L grid simulator and the PBS 2000L bidirectional power supply are used for bidirectional energy storage converter testing
The energy storage market is one of the areas with the most growth potential in the world, and it is expected that energy storage will show a rapid development trend in the context of the global energy transition and the increasing proportion of renewable energy generation. The energy storage market is poised to witness strong growth over the next 5 years due to the huge potential of energy storage and the potential for cost reduction.
With the increasing renewable energy generation and the development of the electricity market, energy storage technology will continue to drive the growth of energy storage demand. In addition, the increasing proportion of solar, wind, and other renewable energy sources in power generation, coupled with the size and development potential of the energy storage market, will drive the rapid growth of energy storage technology worldwide.
Energy storage system is an important technology, which allows people to store the energy used in industry and commerce in some form, so as to facilitate later use, energy storage system is mainly composed of energy storage components, battery management system, energy management system, energy storage inverter and other electrical equipment.
If there are only photovoltaic, wind and oil-fired generators in the system, the operation of the system may be unbalanced, and when the power of renewable energy is greater than the load power, the system may fail, and the energy storage system is a device that converts energy into electricity and stores it to provide backup power for the power system. As the share of renewable energy in the grid continues to increase, energy storage systems will play an increasingly critical role in the balance between renewables** and electricity demand response.
The main application and working mode of energy storage converter PCS
Energy storage converter PCS (power conversion system), also known as bidirectional energy storage converter, the main function is to control the charging and discharging process of the battery, to ensure that the battery stores and releases electric energy safely and efficiently. At the same time, the energy storage PCS can also realize the two-way flow of energy between the grid and the battery, and improve the stability and efficiency of the power system.
PCS is mainly used in power systems that require battery energy storage, such as microgrids, distributed energy systems, smart grids, etc. In these scenarios, energy storage PCS can balance power supply and demand and improve the stability and reliability of the power system. For example, in a microgrid, an energy storage PCS can capture power from the battery in the event of a failure of the main grid to ensure continuous power supply for critical loads.
The working principle of the energy storage converter is a four-quadrant operation converter device that can be controlled on the AC and DC sides, which realizes the AC and DC bidirectional conversion of electric energy. The principle is to control the constant power or constant current through the microgrid monitoring instructions, charge or discharge the battery, and smooth the output of fluctuating power sources such as wind power and solar energy. The PCS adopts dual closed-loop control and SPWM pulse modulation method, which can accurately and quickly adjust the output voltage, frequency, active and reactive power.
The working mode of bidirectional energy storage converter PCS is divided into grid-connected mode, off-grid mode and hybrid mode.
1.Grid-connected mode: The main feature of grid-connected mode is that the energy storage inverter must be synchronized with the existing grid frequency. To synchronize with the grid, the energy storage inverter acts as a current source relative to the grid. In some cases, energy storage inverters must be able to provide voltage support to the grid through reactive power control. According to the requirements of power grid dispatching or local control, PCS converts the AC power of the power grid into DC power during the load trough period of the power grid, and charges the battery pack, which has the function of battery charge and discharge managementDuring the peak load period of the power grid, it converts the direct current of the battery pack into alternating current and feeds it back into the public gridWhen the power quality is not good, feed or absorb active power to the power grid, provide reactive power compensation, etc.
2.Off-grid mode: An island system is a partial "microgrid" in which one or more power generation systems are connected in parallel. The main feature of islanding systems is that the local grid is detached from all large grids, and the rated power of the energy storage system is roughly equal to the total power generated by the local grid. In this system, the energy storage system must be able to act as a power source for the network, providing voltage and frequency control to the local grid. On the other hand, if a power generation unit cannot be synchronized with other power generation units, such as a diesel generator connected to a local power grid, then the energy storage system must be synchronized as a power source. In some cases, the energy storage system also has to be converted between being a power source and being synchronized with the power generation unit. Islanded systems are characterized by energy storage systems connected to local power grids, which may be found in remote mountainous areas or small islands. Common applications include smoothing out power fluctuations caused by variable loads in variable power sources, stabilizing power grids, optimizing fuel use, and regulating power quality.
3.Hybrid mode: The energy storage system is able to switch between on-grid and off-grid mode. The energy storage system is in the microgrid, the microgrid is connected to the public grid, and it operates as a grid-connected system under normal working conditions. Common applications include filtering, stabilizing power grids, regulating power quality, and creating self-healing networks. Loitest provides high power density and efficient test solutions for energy storage PCS.
customersendEnergy storage convertersApplication examples
An energy storage manufacturer used the PAS 5000L series power grid simulator and the PBS 2000L series high-power bidirectional DC power supply to verify the island switching time test of the energy storage converter.
Both the PAS 5000L series and the PBS 2000L series operate in both directions, allowing continuous charge/discharge testing without changing wiring and control. The PAS 5000L series is a regenerative AC power supply with a maximum power of up to 300kVA, which can automatically absorb and reverse power while providing power supply to the grid, and has a built-in island protection test function. The maximum voltage of the PBS 2000L series can reach 2250V, and the maximum power can reach 18mw。
There are two kinds of switching time for energy storage inverter, one is charge and discharge switching, and the large-scale energy storage countercurrent should be able to quickly switch the operating state, which usually requires that the switching time is not more than 200ms between the grid-connected charging state of 90% of the rated power and the grid-connected discharge state of 90% of the rated power, and the other is the switching time of the grid-connected mode and the off-grid mode, and the switching time is not more than 100ms. The PAS 5000L series feedback grid simulator has high-precision voltage and current measurement values compared with bidirectional current conversion and energy feedbackButton operation voltage, frequency, time setting;Provide embedded intelligent PC monitoring system. The advanced direct digital synthesizer (DDS) waveform generation technology is used to make the output frequency stable, good continuity, high measurement accuracy, and suitable for measuring the peak current of nonlinear loads.
At the same time, the PAS 5000L series power grid simulator and the PBS 2000L series bidirectional DC power supply are feedback products, with a feedback efficiency of 95%, which can feed back the power grid without pollution in the high-power test, meet the needs of environmental protection and save a lot of electricity and heat dissipation costs.
Functions and application areas of the PBS 2000L series of bidirectional DC power supplies.