Abstract: In response to the power supply needs of highly sensitive and large-capacity users, the impedance-isolated medium-voltage power supply quality comprehensive improvement system topology has advantages in output power, operating loss, and detection requirements. With the goal of achieving power supply quality improvement and MW-level power, an output voltage control suitable for grid-connected and off-grid operation of the system is proposed. The operating principle and mathematical model of the system are analyzed. Combined with the isolation of the grid through reactors, the voltage-power autonomous control is proposed to stabilize the load voltage and increase the inertia of the system, and the steady-state output of active power is realized without static difference. The system damping optimization control based on filter capacitor current feedback is introduced to suppress the transient resonance and improve the stability of the system. In the mathematical model, the impact of the output current on the load voltage stability is quantitatively analyzed, and the output voltage optimization control based on the virtual series impedance is proposed to improve the load power quality in real time. The results show that the system can maintain high quality load voltage output and power support in real time when the megawatt load power changes and various power quality problems occur in the grid. And the effectiveness of the proposed control is verified by simulation comparison.