In a period of sampling points

400 Hz medium frequency inverter is 8 times less than inverters of 50 Hz

greatly reducing the control accuracy and difficultly eliminating the static error. In order to realize the system’s static error tracking and to overcome the influence of uncertain parameters on the performance of the system

we take the load and cable parameters acting as uncertain factors on the foundation of mathematical model of single phase static frequency power supply

and design the robust controller and 10 k W test prototype based on the principle of H

∞

mixed sensitivity method. The simulation and experiments are carried out by Matlab software and the simulation and experiment results show that the designed robust controller can make the system have good dynamic and static performance and robust performance. The steady state voltage

is between 114.5 V and 115.5 V

and the dynamic recovery time is less than 10 ms

which shows the designed robust controller can completely suppress the influence of the line cable’s uncertainty.