By adding an energy storage device to the inverter, with a proper control scheme, the inverter can emulate the behavior of a synchronous generator with a certain amount of inertia. This system is called virtual synchronous generator (VSG). By adding Voltage amplitude and power controls to VSG, voltage sag ride-through capability of system improved. In our research we show that although in the case of symmetrical voltage sag, voltage and power controls are effective, but in unbalanced voltage sag conditions, especially for sags with the critical characteristics, additional controls are not so effective in over current suppression.