两级式储能逆变器并离网控制技术

随着新能源的大规模应用，储能装置作为一种可控电源，因具有调峰幅度大、响应速度快等优点而在保证微电网正常运行方面具有重要作用。介绍了一种两级式储能逆变器，一级是三相全控桥构成的网侧变换器，另一级是3个交错并联回路构成的直流变换器。阐述了该储能逆变器在并网和离网工作模式下的控制原理及并离网切换的技术关键点。通过MATLAB仿真验证了该储能逆变器采用所提控制策略可以实现并网、离网的正常运行以及并离网切换的顺利过渡，采用3个交错并联回路结构的直流变换器可以提高总输出电流能力，通过载波移相可以减小总输出电流波动。储能逆变器可靠地实现了微电网的并网和离网运行控制，有效地改善了可再生能源发电输出功率的连续性，为新能源领域进一步发展提供了技术保障。

On-Grid/Off-Grid Control Technology of Two-Stage Energy Storage Inverter

In the large-scale application of new energy, energy storage device acts as a kind of controllable power supply. It has the advantages of large amplitude of peak regulation and fast response, so it plays an important role in ensuring the normal operation of microgrid. A two-stage energy storage inverter is introduced: one stage is the grid side converter which is composed of three-phase full control bridge, and the other stage is the DC converter which is composed of three interleaved parallel circuits. Then, the control principles of the energy storage inverter in on-grid/off-grid operation mode and the key points of switching between on-grid/off-grid are introduced. The MATLAB simulations show that the proposed control strategy can realize the normal operation of on-grid/off-grid and the smooth transition of switching between on-grid and off-grid, and the DC converter can improve the total output current capacity by three interleaved parallel circuits and reduce the total output current fluctuation by carrier phase shifting. The energy storage inverter can reliably realize the on-grid/off-grid operation control of microgrid. The continuity of renewable energy power generation output power is effectively improved, and the technical support for the further development of new energy field is provided.