China Machinery Industry Standard (CMIS) GB/T 12326-2008 prescribed in the islanded operation mode, microgrid inverter (MGI) output voltage dynamic transient range is less than 10% when the resistive load is switched rapidly between 0% and 100%. The three-loop power virtual synchronous generator (VSG) control methods are commonly used in MGI units to share the loads among the parallel MGIs. However, the transient output voltage of the MGI is beyond the CMIS when the resistive load steps sharply. In order to meet the CMIS, an output voltage differential feedback improved algorithm was employed. Comparing to the traditional control method, the improved method could obtain satisfying dynamic transient voltage suppression, resonance inhibition and improve system stability. These theoretical findings were eventually verified experimentally both on simulation and laboratory prototypes.