Microgrids are composed of distributed energy resources (DERs), storage systems, electric vehicles, flexible loads, and so on. They can operate connected to the main electrical network (network operation) or separated from the network (off-grid operation). The production of renewable energy can vary and therefore can cause deviations in voltage especially in stand-alone operation. This can affect the stability of microgrids. This paper proposes an optimization model for the efficient management of controllable devices in microgrids with the aim of minimizing voltage deviations. RSE’s Distributed Energy Resources Test (DER-TF), which is a low voltage microgrid located in Italy, was used to validate the algorithm. The microgrid data was acquired online through a software platform (REDIS) and an optimization algorithm based on harmonic search was applied to it in order to control the parameters of the devices. The experimental results show that the optimization approach based on harmony search finds the control parameters correctly and can help the system obtain a better voltage profile.