基于SVPWM的三电平变频器无中性线控制中点电位调节能力

Neutral-point potential regulation capability of three-level inverter under no-neutral-wire control based on SVPWM

目前,鲜有文献对三电平变频器无中性线下中点电位调节能力边界展开研究。为此,针对船舶三电平推进变频器无中性线控制需求,给出了基于空间矢量脉冲宽度调制(space vector pulse width modulation,SVPWM)的三电平变频器无中性线控制中点电压平衡策略。首先,理论推导了SVPWM策略下无中性线控制不同扇区下中点电位调节能力的边界,并在几种典型调制比下对中点电位调节能力进行了离线仿真验证,结果与理论相符;然后,搭建了控制器硬件在回路实时仿真平台,实验验证了基于SVPWM策略下中点电位控制的有效性及中点电位调节能力的准确性。相关研究结论可为推进变频器直流支撑电容设计及无中性线下变频器安全运行边界确定提供技术支撑。

Currently,few precedents have conducted study on the neutral-point potential regulation capability boundary of three-level NPC inverter under no-neutral-wire control.Therefore,the no-neutral-wire neutral-point potential balancing strategy of three-level NPC inverter based on space vector pulse width modulation(SVPWM)was proposed for the control requirements of ship-propelling.Firstly,the neutral-point potential regulation capability boundary in different sectors under no-neutral-wire control was quantitatively deduced under SVPWM.On the basis of above,the capability of neutral-point potential regulation under several typical modulation indexes was verified by off-line simulation.Then,hardware-in-loop real-time simulation platform was established and the correctness and effectiveness of the proposed method were verified by experiment.The conclusions of the study can provide technical support for designing the DC support capacitor for propelling inverter and determining the no-neutral-wire safe operation boundary of the inverter.