随着能源危机和环境问题日益显现，风能、太阳能等可再生能源受到了广泛的关注，近年来得到了迅速发展。而风电、光伏等大量接入电网，其间歇性和随机性将会增大电网的电压、频率波动，影响供电可靠性和电能质量。因此，有必要通过配置储能设备，减小新能源并网对电网的冲击。不过，目前储能系统的发展仍面临着成本和安全两大挑战。因此，本文以模块化多电平复合变换器（Modular Multilevel Hybrid Converter, MMHC）拓扑为基础，对储能变流器（Power Conversion System, PCS）的调制策略、控制策略和并网预同步方法进行了研究。 本文首先介绍了储能PCS拓扑和相关控制策略的研究现状。其次，介绍了MMHC拓扑及其调制策略，提出了多维耦合模糊控制算法，通过对锂电池的电化学特征进行模糊化处理，得到各个维度的影响因子曲线，根据各电池模块的实时状态计算影响因子，结合PCS的调制策略来调整不同电池模块间的功率分配，并且通过仿真对多维耦合模糊控制算法进行了验证。再次，介绍了虚拟同步发电机（Virtual Synchronous Generator, VSG）控制算法，分析了储能PCS的有功-频率和无功-电压控制方法，设计了MMHC储能PCS在离网和并网运行时的控制策略，通过搭建小信号模型对控制参数进行了优化设计，并通过仿真验证了VSG控制策略的有效性。然后，针对储能PCS并网预同步环节中采用锁相环的方法所存在的问题，介绍了两种无锁相环的并网预同步方法，并利用仿真对两种方法的预同步效果进行了对比分析。最后，搭建了基于MMHC拓扑的储能PCS实验平台，在并网条件下对VSG控制策略进行了实验验证，实验结果表明，储能PCS能够快速、准确的响应电网的功率指令，并且可以在电网电压出现频率或幅值波动时提供有功或无功功率支撑，验证了本文提出的VSG并网控制策略的有效性。

With the emergence of energy crisis and environmental problems, renewable energy sources such as wind energy and solar energy have been widely concerned and developed rapidly in recent years. However, after a large number of power sources such as wind power and photovoltaics are connected to the power grid, their intermittence and randomness will increase the voltage and frequency fluctuation of the power grid and affect power supply reliability and power quality. Therefore, it is necessary to reduce the impact of new energy grid connection on power grid by configuring energy storage equipment. However, the development of energy storage system still faces two major challenges: cost and safety. Therefore, based on the modular multilevel hybrid converter (MMHC) topology, this thesis studies the modulation strategy, control strategy and pre-synchronization method of the power conversion system (PCS). Firstly, this thesis introduces the research status of PCS topology and related control strategies. Secondly, MMHC topology and its modulation strategy are introduced, and a multi-dimensional coupling fuzzy control algorithm is proposed. By fuzzifying the electrochemical characteristics of lithium batteries, the influence factor curves of each dimension are obtained, and the influence factors are calculated according to the real-time state of each battery module, and combining the modulation strategy of PCS, the power is distributed among different battery modules. And the multi-dimensional coupling fuzzy control algorithm is verified by simulation. Thirdly, the control algorithm of virtual synchronous generator (VSG) is introduced, the active power-frequency and reactive power-voltage control methods of PCS are analyzed, the control strategy of MMHC PCS in off-grid and on-grid operation is designed, the control parameters are optimized by building a small signal model, and the effectiveness of the control strategy of VSG is verified by simulation. Fourthly, in view of the problems existing in the method of using phase-locked loop in the pre-synchronization of PCS, two pre-synchronization methods without phase-locked loop are introduced, and the effects of the two methods are compared and analyzed by simulation. Finally, an experimental platform of MMHC PCS is built, and the VSG control strategy is verified under the grid-connected condition. The experimental results show that the PCS can respond to the power command of the grid quickly and accurately, and can provide active or reactive power support when the grid voltage fluctuates in frequency or amplitude, which verifies the effectiveness of the VSG grid-connected control strategy proposed in this thesis.