Hybrid pulse width modulation technique for wide speed range with low cost drivers on IPMSM

The control performances of the hybrid PWM inverter according to the phase current measuring method is presented in this paper. The hybrid PWM strategy consists of space vector pulse width modulation (SVPWM) and 6-step modulation. SVPWM is performed to reduce the harmonic components in the low speed region, and 6-step modulation is applied to increase the maximum speed of the IPMSM in the high speed region. Therefore, it is possible to obtain a good performance in both the low speed range and high speed range. However, due to the inverter including lag-shunt sensing methods has the current immeasurable regions, the 6-step modulation cannot be implemented completely. In this paper, quasi-six step modulation is proposed using the modified voltage vector. The validity and usefulness of the proposed PWM technique is verified by MATLAB/ Simulink and experimental results.