中点活箝位三相五级逆变器研究

二极管中点箝位(Neutral point clamped,NPC)多级逆变器因其输出电压、功率较高,适用于中、大功率装置的应用。为了得到它输出正弦波形的电压和电流,常要应用脉宽调制(PWM)。实践证明,这种中点箝位多级逆变器中开关元件损耗不均匀,如NPC三相三级逆变器中只有外围的6只电力电子开关元件可作PWM控制,导致其开关损耗和发热远大于内圈6只元件。为解决上述问题,应充分发挥多级逆变器潜力,中点活箝位(Active NPC,ANPC)多级逆变器被提出。对于中、大功率风力和太阳能光伏发电的电流波形,一些标准要求愈来愈严,希望省去滤波器,为此,对ANPC三相五级逆变器作了分析,并提出采用PWM控制原理,仿真结果表明达到了较好效果,这为进一步开发实际装置奠定了基础。

Research on ANPC three-phase five-level inverter

Multi-level inverter （MLI） with diode neutral noint clamned （NPC） is suitable for medium and large oower anolication, because it outnuts high voltaze and nower. In order to obtain sinusoidal voltage and current from the inverter, PWM control is needed. However the oractice shows that Dower loss of nower electronic switch devices for NPC MLI is different. For instance, only six external switch devices inside NPC three-nhase three-level inverter are able to realize control with PWM , which causes them more loss and higher heating, than that of other six internal switch devices. In order tosolve above nroblems and fully develon the ootential of multi-level inverter, active neutral noint clamned （ANPC） MLI is suggested. For the current waveforms of medium and high Dower wind and nhotovohaic, some standards become more and more strict, and hone to save filter. The ooeration Drinciole and PMW control of ANPC three-nhase five-level inverter are analyzed. The simulation results show that extdected aim is reached, and it has laid a foundation for develoning, apractical device.