摘要
载波移相(CPS-PWM)应用于级联H桥型(CHB)多电平逆变器时,虽然各级联单元具有功率均衡的特点,但输出电压的直流电压利用率较低,且低调制度时谐波性能比较差。针对这2个问题,提出一种改进的CPS-PWM调制技术,该调制技术基于载波形状自由度,利用改进的载波代替原CPS-PWM中的三角形载波进行调制,通过状态空间平均法计算出在改进后的载波下逆变器输出电压的基波幅值和各个级联单元的输出电压,并和逆变器在CPS-PWM技术下的输出电压对比分析,改进的CPS-PWM技术可以显著地提高输出电压的直流电压利用率,改善低调制度的谐波性能,且和CPS-PWM技术一样,各级联单元输出功率能够实现自然均衡。该调制技术以CHB型五电平逆变器为例,通过实验、仿真验证了该技术的正确性。
When carrier phase shift PWM(CPS-PWM)is applied to cascaded H-bridge(CHB)multi-level inverters,although it has the advantage of self-equalization of output power among cascaded units,the output The DC voltage utilization rate of the voltage is low,and the harmonic performance is relatively poor when the modulation degree is low.Aiming at these two problems,an improved CPS-PWM modulation technique was proposed,which is based on the freedom of carrier shape,the improved carrier was used to replace the triangular carrier in the original CPS-PWM for modulation,and was calculated by the state space average method.The fundamental wave amplitude of the inverter output voltage and the output voltage of each cascaded unit under the improved carrier were analyzed and compared with the output voltage of the inverter under CPS-PWM technology.The improved CSP-PWM The technology can significantly increase the DC voltage utilization of the output voltage,improve the harmonic performance at low modulation degrees,and the output power of all levels of the unit can be naturally balanced like the CPS-PWM technology.The modulation technology takes the CHB five-level inverter as an example,and correctness of the relevant conclusions is verified through simulation and experimental results.
作者
叶满园
陈乐
康力璇
YE Man-yuan;CHEN Le;KANG Li-xuan(School of Electrical and Automation Engineering,East China Jiaotong University,Nanchang 330013,China)
出处
《电机与控制学报》
EI
CSCD
北大核心
2021年第3期134-142,共9页
Electric Machines and Control
基金
国家自然科学基金(51767007)
江西省重点研发项目(20202BBEL53034,20192BBEL50011)。
