T型三电平逆变器合成脉冲宽度调制相电流重构策略

T-Type Three-Level Inverter Composite Pulse Width Modulation Phase Current Reconstruction Strategy

针对传统T型三电平逆变器空间矢量脉冲宽度调制单电流传感器相电流重构技术存在不可观测区问题,该文分析T型三电平中点电流采样原理以及中点电流不可观测区的存在机理,提出中点电流单传感器采样合成脉冲宽度调制相电流重构策略,通过在不同区域对不满足最小采样时间要求的可观测电压矢量进行补偿,同时利用合成零矢量原理对补偿矢量进行抵消以满足伏秒平衡原理,消除了不可观测区。最后通过实验验证所提方法的电流重构误差低于2.5%,相电流总谐波畸变率低于3.21%,可为控制系统提供准确的重构相电流。

The traditional single-current sensor based phase current reconstruction technology used to modulate the space vector pulse width in the T-type three-level inverter has an unobservable region.Therefore,the sampling principle of the T-type three-level neutral current and the existence mechanism of the unobservable region of the neutral current are analyzed,and a phase current reconstruction strategy combined with the neutral current single-sensor sampling and pulse width modulation is proposed.By compensating the observable voltage vector that does not meet the minimum sampling time requirement in different regions,and using the composite zero vector principle to satisfy the principle of volt-second balance,the unobservable region is eliminated.It is shown that the current reconstruction error of the proposed method is less than 2.5%,and the phase current total harmonic distortion is less than 3.21%,which can provide accurate reconstructed phase current for the control system.