In the motor control, the over modulation algorithm could effectively improve the inverter output voltage, of great significance to improve the motor speed. To improve the shortcomings of space vector pulse width modulation DC bus voltage underutilization, a single mode overmodulation algorithm based on SVPWM was studied, carried out the amplitude of the fundamental voltage and the harmonic content of the output voltage. Aimed at the problem that the amplitude of the fundamental output voltage of the overmodulation zone did not coincide with the reference voltage, the controllability analysis was made on the relationship between the target modulation ratio and the given modulation ratio, made the fitting curve and found the function relation and carried out simulation and experimental verification of the overmodulation algorithm. The simulation results and experimental results showed that the theoretical analysis was correct and feasible.