High-power asynchronous machine can be used as the main generator of diesel locomotive and marine power system. The standalone power system of asynchronous generator based on four-quadrant converter is proposed. The magnetic field energy required by the machine must meet the minimum requirements for power generation, and the balance between power generation and load power must be ensured. Therefore, the initial voltage and capacitance of the DC-link capacitor are first analyzed and calculated. After that, the simple and easy slip prediction control is designed, that is, the given electric frequency takes into account the influence of the slip ratio. A power generation system is designed with an asynchronous machine as the main generator to achieve a DC voltage of 750 V, with an output power of up to 520 kW. Simulate the system for different operating conditions. The stable DC voltage is maintained under full load at different speeds. When suddenly unloading or loading 50 %, it can restore stable DC voltage in 10 ms time. In the case of stepless speed regulation and stepped speed regulation of diesel engine, the generator can still generate a stable DC voltage with loads of different power levels. The simulation results show that the power generation system has good load capacity and good dynamic performance.