The voltage stability of islanding microgrid can be seriously subjected to high penetration level of highly-nonlinear induction motor(IM)loads. For this reason

according to the principle of power balance in power systems

the dynamic coupling relation between the system voltage and motor slips is deduced in theory for the microgrid with multiple IM loads. And the reason the induction motor load is more sensitive and the dynamic coupling characteristics of IM load slips and system voltage are related to microgrid stability is given. A microgrid with master-slave control scheme is developed in MATLAB/Simulink environment

including wind turbine generator

photovoltaic

diesel synchronous generator and the energy storage device. On this basis

the voltage stability of microgrid is studied on both multiple induction motors superposition starting under different conditions and fault conditions. Then measures are proposed to improve the voltage stability of microgrid with multiple IM loads. The research results show that the interaction among multiple induction motors has significant impact on the voltage stability of the microgrid. Moreover

the critical fault clearing time of tandem microgrid with master-slave control is doubly restricted by the distance from three-phase short-circuit fault point to the point of IM loads and the point of main control unit. In addition

the strategies of superimposed starting and fault point load shedding can significantly improve the voltage stability of the microgrid. Conclusions have provided a theoretical basis for stability and control studies of multi-source microgrid with IM loads. This work is supported by Fundamental Research Funds for the Central Universities(No. CDJZR12150024).