This paper presents the process of updating and tuning the automatic voltage regulators of two synchronous micro machines (round rotor and salient pole) of a micro network power system simulator. This micro network is an important part of the Laboratory Power Systems Simulator, which is being developed by the Electric Machines and Power System Dynamics research group of SEPI-ESIMEZ-IPN. Basics of PID excitation system controls tuning are presented, using computer simulations. Resulting AVR parameters are tested by means of experimental simulations on the physical system, demonstrating an adequate performance of the regulators.