3-phase current reconstruction of permanent magnet synchronous motor drives using a single DC-link current sensor

In the application of conventional 3-phase current reconstruction methods using a single DC-link current shunt, the self-switch coniguration of space vector pulse width modulation (SVPWM) may cause a problem of insufficient measuring time in certain regions. To cope with this problem, in this paper, we propose a switching strategy that exploits the advantages of SVPWM, the measurement vector insertion method (MVIM), and the pulse-width modulation method without using the null switching states method (NSVM). In the proposed switching strategy, the MVIM is employed in the low-modulation-ratio region and the sector boundary region of the middle-modulation-ratio region, while the NSVM is adopted in the sector boundary region of the high-modulation-ratio region. In addition, we used Matlab/Simulink in this study to construct a simulated environment to conduct an in-depth study of the differences among various current construction methods as well as the size of the immeasurable region.