A Hybrid SVPWM Scheme For Motor Drive Using DC Bus Current Sampling Technique

Aiming at the technical problem of phase current reconstruction of DC bus single current sensor based on voltage space vector pulse width modulation(SVPWM), a hybrid SVPWM scheme based on the DC bus current sampling technique is proposed in this paper. First, the current sampling mechanism of the traditional SVPWM method is analyzed, and the mechanism of the unobservable region in the DC bus sampling system is revealed. Second, by defining the minimum sampling time, the unobservable area of DC bus sampling is divided accurately. Then, in the unobservable area, the duration of the non-zero switching state is extended by shifting the carrier accordingly, thus reconstructing the phase current in the unobservable area of the traditional SVPWM. Finally, the experimental results show that the three-phase current signals of the inverter can be reconstructed by using the hybrid SVPWM scheme, while providing low current harmonic distortion of inverter output. Besides, the proposed algorithm demonstrates attractive performance during both steady-state and dynamic operations in the phase current reconstruction and regulation.