## 5 Hybrid AC/DC Microgrid Control Strategies
### Power Generation Control
A coordinated control strategy is designed for a microgrid with DC/AC loads and hybrid energy resources. Initially, for a distributed converter, a local-level coordinated control strategy is designed. A method based on model predictive voltage and power control is designed for DC/AC interlinking converters to make sure smooth power transfer among DC and AC subgrids and to deliver high-quality voltages. Meanwhile, efficient grid connection and synchronization can be attained. Finally, an energy management scheme at a system level is implemented to confirm balanced operation beneath consumption conditions and variable power generation. The effectiveness of a recommended control strategy is demonstrated on a 3.5 MW system. The perforation of Renewable Energy Resources, i.e., wind energy systems and photovoltaic systems, is gradually expanding into traditional power systems. On the other hand, there is a drawback of losses in AC-DC-AC conversion in renewable energy resources, drop-in power quality, and increase in the cost of components [102]. Furthermore, in recent times, the demand for power of DC load, i.e., electric vehicles and telecom exchange network systems, is increasing. For the telecom network systems, the DC loads were associated with the main AC grids under some converter phenomena in traditional power systems, which cause the enhanced cost and occurrence of AC to DC conversion losses. The appropriate solution to lessen the numerous reversal conversions inside the telecom exchange is a hybrid microgrid for the dispersed DC and AC power generations. Therefore, a droop-controlled scheme was used among DC and AC microgrids for the hybrid microgrid for energy management and managed power and voltage regulation inside a telecom exchange. The required power is shared among DC and AC microgrid by the droop controller and improves operational consistency of the DC loads, such as electric vehicles and telecom exchanges. For the betterment of interlinking of various distributed generation systems in the microgrid and manipulating the major characteristics of both DC and AC microgrid, an improved hybrid microgrid was designed. For the connection of these microgrids, an interlinking DC/AC converter is required with a control strategy and proper power management. The interlinking converter was planned to work as a load at one microgrid and at the same time work as a supplier to the second microgrid, and the power management system is responsible for the power-sharing in both DC and AC sources of a microgrid during an islanding operation. There are management issues and power flow control problems between different sources distributed over both DC and AC microgrids. A decentralized sharing of power method is designed to reduce the necessary communication among microgrid and distributed generation systems. The efficiency of a system enhances and the cost decreases by allowing different DC or AC sources and loads to be submissively placed in order to reduce the demanded power conversion stages in a hybrid microgrid. The performance of the presented system is tested on the simulation in PSCAD/EMTDC software [103]. Under islanding operation conditions, a control method was designed for the hybrid microgrid. Several control schemes for DC subgrids and AC subgrids were examined. According to the operational reliability and the requirement of power-sharing, an additional key control scheme is designed for interlinking a converter with energy storage or DC-link capacitor, which will dedicate to the appropriate power distribution between DC and AC subgrids to sustain DC and AC side voltage balanced. The developed control methods specified for the DC and AC subgrids were combined with an interlinking converter. The power flow shifted between subgrids to enhance the efficiency and operating quality can be managed by interlinking converters [104]. A new energy management technique is designed for hybrid DC/AC microgrids in the field of remote communication.