In the process of accelerating the realization of dual carbon goals and building a new power system, energy storage technology is gradually becoming one of the key technologies to support the stable operation of the new power system and optimize resource allocation. Among them, PCS (Power Conversion System) energy storage converter is the core equipment of the energy storage system, and its performance and application directly affect the overall efficiency and stability of the energy storage system. This article will conduct an in-depth analysis and interpretation of the definition, working principle, main features, working mode, application scenarios and future development trends of PCS energy storage converter.
01
Definition of PCS energy storage converter
PCS energy storage converter, full name Power Conversion System, is a key device in the energy storage system, used to realize energy conversion and bidirectional flow between energy storage batteries and power grids. It can convert DC power into AC power or AC power into DC power to meet the charging and discharging requirements of the power grid for energy storage systems. PCS energy storage converter plays the role of "bridge" in the energy storage system, connecting energy storage batteries and power grids to ensure efficient and stable operation of energy storage systems.
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Working principle of PCS energy storage converter
The working principle of PCS energy storage converter is mainly based on power electronics technology, which realizes the conversion and bidirectional flow of electric energy by controlling the on and off of switching devices. When the power grid needs the energy storage system to discharge, the PCS energy storage converter converts the DC power in the energy storage battery into AC power and outputs it to the power grid; when the power grid needs the energy storage system to charge, the PCS energy storage converter converts the AC power in the power grid into DC power and stores it in the energy storage battery. During the charging and discharging process, the PCS energy storage converter also needs to perform precise power control and energy management according to the needs of the power grid and the status of the energy storage battery to ensure the stable operation and efficient utilization of the energy storage system.
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Main features of PCS energy storage converter
1. Efficient energy conversion: PCS energy storage converter adopts advanced power electronics technology and control strategies to achieve efficient and stable energy conversion and bidirectional flow. Its conversion efficiency is as high as 95%, which can significantly reduce the operating cost of the energy storage system.
2. Precise power control: PCS energy storage converter has precise power control capability and can make real-time adjustments according to the needs of the power grid and the status of the energy storage battery. Through precise power control, PCS energy storage converter can achieve rapid response and precise adjustment of the energy storage system, and improve the stability and reliability of the power system.
3. Intelligent energy management: PCS energy storage converter also has intelligent energy management function, which can be intelligently dispatched and optimized according to the load of the power grid and the status of the energy storage battery. Through intelligent energy management, PCS energy storage converter can maximize the utilization of energy storage system and minimize the loss, and improve the economy and environmental protection of the entire power system.
4. Flexible configuration and expansion: PCS energy storage converter adopts modular design, which can be flexibly configured and expanded according to actual needs. By increasing or decreasing the number of modules, the capacity of the energy storage system can be accurately adjusted to meet the needs of different application scenarios.
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Working mode of PCS energy storage converter
1. In grid-connected mode, the bidirectional energy conversion between the battery pack and the grid is realized according to the power command issued by the upper-level dispatcher; such as charging the battery pack during the low load period of the grid and feeding back to the grid during the peak load period of the grid;
2. Off-grid/isolated grid mode, when the set requirements are met, it is disconnected from the main grid and provides AC power that meets the power quality requirements of the grid to some local loads.
3. Hybrid mode, the energy storage system can switch between grid-connected mode and off-grid mode. The energy storage system is in the microgrid, the microgrid is connected to the public grid, and operates as a grid-connected system under normal working conditions. If the microgrid is disconnected from the public grid, the energy storage system will work in off-grid mode to provide the main power supply for the microgrid. Common applications include filtering, stabilizing the grid, adjusting power quality and creating self-healing networks.
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Application scenarios of PCS energy storage converter
1. Energy time shifting: In the user-side energy storage system, the PCS energy storage converter can be used for energy time shifting, storing the excess photovoltaic power generation during the daytime, and releasing it through PCS at night or in rainy weather when there is no photovoltaic power generation, which can achieve the maximum self-use of photovoltaic power generation.
2. Peak-valley arbitrage: In the user-side energy storage system, especially in industrial and commercial parks that implement time-of-use electricity prices, the PCS energy storage converter can be used for peak-valley arbitrage, by charging during the period of low electricity prices and discharging during the period of high electricity prices, to achieve low charging and high discharging arbitrage, so as to save the overall electricity cost of the park.
3. Dynamic capacity expansion: In scenarios with limited power capacity, such as electric vehicle charging stations, PCS energy storage inverters are configured with energy storage batteries for dynamic capacity expansion. During peak charging, PCS energy storage inverters discharge to provide additional power support; during low-peak charging, PCS energy storage inverters charge and store low-priced electricity for backup, which can achieve peak-valley arbitrage and dynamically expand the capacity of charging stations.
4. Microgrid system: In a microgrid system, PCS energy storage inverters can achieve coordinated control of distributed power sources and energy storage systems, improving the stability and power supply quality of microgrids. Through the precise power control and intelligent energy management of PCS energy storage inverters, the balance and optimal scheduling of power supply and load in microgrid systems can be achieved.
5. Frequency and peak regulation of power systems: In power systems, PCS energy storage inverters can be used for frequency and peak regulation to improve the stability and reliability of power grids. When the grid load is at a peak, the PCS energy storage inverter can release the energy in the energy storage battery and provide additional power support for the grid; when the grid load is at a low point, the PCS energy storage inverter can absorb the excess energy in the grid and charge the energy storage battery for later use.
Growatt 140-250k energy storage inverter
06
Development trend of PCS energy storage inverter
Currently, centralized PCS is widely used in large energy storage power stations. A high-power PCS controls multiple clusters of parallel batteries at the same time, and the imbalance problem between battery clusters cannot be effectively handled; while string PCS, a small and medium-power PCS only controls one cluster of batteries, realizing one cluster one management, effectively avoiding the barrel effect between battery clusters, improving system life, and increasing the discharge capacity of the entire life cycle. The trend of large-scale application of string PCS has taken shape. In the integrated industrial and commercial energy storage cabinet, string PCS has become the mainstream solution in the industry, and will also be applied on a large scale in large energy storage power stations in the future.
With the rapid development of new energy and smart grids and the continuous advancement of energy storage technology, PCS energy storage converters will face greater development opportunities and challenges. In the future, PCS energy storage converters will develop in a more efficient, intelligent and flexible direction.
On the one hand, with the continuous advancement of power electronics technology and the continuous application of new materials, the conversion efficiency of PCS energy storage converters will be further improved. On the other hand, with the continuous development and application of technologies such as big data, cloud computing, and artificial intelligence, the intelligent energy management capabilities of PCS energy storage converters will be further enhanced, which can better meet the needs of the power system and optimize scheduling. In addition, with the continuous expansion and deepening of the application scenarios of energy storage systems, PCS energy storage converters will also face more customized needs and innovation challenges.