T型三电平逆变器相电流重构的相位延迟误差补偿方法

Aiming at the unobservable areas (UAs) and phase delay error (PDE) in the neutral current sensor phase current reconstruction (NCS-PCR) method of T-type three-level inverter (TThLI), the three-phase current slope corresponding to the basic voltage vector and the existence mechanism of the PDE are analyzed. Based on the volt-second balance principle and the synthetic zero vector principle, the original switching sequence is changed to obtain a sufficient sampling window, thereby eliminating the UAs of the neutral current. By adding a third current sampling and constructing an error component based on the dynamic current double sampling mechanism, the reconstructed current is compensated in real time within the carrier period, thereby achieving PDE compensation. Accordingly, this paper proposes a PDE compensation method for phase current reconstruction of TThLI. The experimental results show that the proposed method realizes the effective reconstruction of the phase current in the UAs, greatly reduces the PDE, improves the distortion of the reconstructed current, and the maximum reconstruction error is as low as 2.85%. Compared with the existing method, the proposed method simultaneously addresses the UAs and PDE, offering advantages such as minimal phase delay, low reconstruction error, and no additional switching loss.