The SVG usually operates in the grid-following mode to suppress the voltage fluctuation and reduce voltage deviation, which needs to synchronize with the grid voltage. When the voltage is severely deviated and distorted in a weak grid, the voltage control mode (VCM) may be more applicable for the SVG, which can quickly respond to and adjust the output voltage of SVG to restore the grid voltage to a stable and reasonable range. However, the SVG does not have an active power source and it usually connects to the bus with an L-filter, where it is difficult to operate in VCM. Therefore, to solve the problem, an improved voltage control method is proposed to realize indirect control of grid voltage. The dc-link capacitor voltage is used for the synchronization, and the voltage difference between the terminal of the inverter and ac bus is regulated to control the power flow. Meanwhile, a virtual impedance control method is proposed to limit the current, where the SVG can support the reactive power even in a situation with terrible voltage quality. Finally, with the simulation verification, the proposed method can quickly provide reactive current when the grid fault occurs, which can effectively maintain the voltage stability in the weak grid.