Current Reconstruction of Three-Phase Voltage Source Inverters Considering Current Ripple
Yongpeng Shen, Di Liu, Weihua Liang, Xizheng Zhang
Abstract
Continuous and stable acquisition of accurate three-phase currents information is critical to vector control. The immeasurable areas (IAs) is the most intractable problem in the traditional single current sensor phase current reconstruction (SCS-PCR) technology. In addition, the change of the sampling position owing to the influence of the IAs makes the current ripple tend to be serious, which further increases the current distortion and decreases the current reconstruction accuracy. This article is the first to investigate the influence of the IAs and the current ripple of SCS-PCR. A midpoint value (MPV) random space vector pulsewidth modulation (RSVPWM) reconstruction strategy is proposed, which is based on the Thevenin equivalent circuit of the sampling circuit of SCS-PCR. RSVPWM constructs a current sampling window that satisfies the minimum sampling time to complete two sequential samplings, while the MPV strategy obtains the mean value of two sampling values in the in-phase dynamic current to reduce current ripple. The proposed MPV RSVPWM reconstruction strategy does not require the insertion of redundant voltage vectors and major computation and is not limited to a particular PWM technology. The experimental results verify the accuracy and practicability of the proposed method.