A Single Current Sensor Reconstruction PMSM Drive Based on Shift PWM Compensation Considering Saturation and Sampling Offset

The single current reconstruction method is particularly beneficial in applications where space and cost are critical such as household appliances, etc. By sampling DC bus current twice, it is possible to reconstruct the three phase current from applied space voltage pulse width modulation (SVPWM). However, there are some existing unmeasurable areas and also sampling offset from current sampling circuit. The shift PWM strategy during the sectors variation and at low modulation region has been proposed to acquire enough time for sampling window. The saturation effect for PWM shift is discussed to maximize utilization of the linear modulation region. By adding the trigger condition of zero voltage vector, the influence of sampling offset is compensated. Simulation compares the reconstructed current error, total harmonics distortion and steady-state performance of the proposed algorithm.