摘要
分析了二极管钳位型多电平逆变器在全负载范围内的电容电压平衡问题。首先在五电平逆变器数学模型的基础上对电容电压平衡规律进行分析;然后详细研究了逆变器开关切换规则与PWM控制策略,进一步提出采用目标函数最优的方法对可行开关序列寻优,实现电容电压平衡控制。仿真分析得出了全负载范围内的电容电压平衡域曲线。结果表明,在高功率因数和大调制比下电容电压很难达到动态平衡,五电平逆变器很难直接应用于全速度范围的中压交流调速领域。
The dc-link voltage balance problem of three-phase multi-level diode clamped inverter in full load range is analyzed in this paper. First of all, the voltage balance law of dc-link is analyzed based on the model of five-level inverter. Then, the switching rules of the PWM inverters are studied in detail. And accordingly, the selection of switching sequences by optimal control method is proposed in order to achieve the voltage balance control. The results of simulations show the boundary of voltage balance under all conditions of load. The conclusion is that when the load power factor and modulation ratio are higher than certain values, the dc-link voltages can not be kept balanced. So the five-level inverter with single dc source can hardly be applied directly to medium voltage drive in full speed range.
出处
《电工技术学报》
EI
CSCD
北大核心
2008年第1期77-83,共7页
Transactions of China Electrotechnical Society
基金
国家自然科学基金资助项目(50677033)
