The paper introduced the operation principle of commonly used diode-clamped three-level inverter which is modulated by space voltage vector pulse width modulation method. The paper is aimed at analyzing the problem of unbalance capacitance voltage of the inverter in practical application, and it proclaims the method that detects the difference value of the two capacitances voltages at DC-side and instantaneous value of the current at neutral point. These values are used in hysteresis control to cut over two equivalent space vector pulse trains so as to keep the balance of capacitance voltage. The result of the experiment shows that the method can suppress the unbalanced degree of capacitance voltage effectively, and it makes the unbalanced degree of capacitance voltage less than double width of hysteresis. The switching loss of device and switching frequency is lower, and the modulation method is simpler and easier to operate in digital controller, and it has some useful value.%对应用较多的空间电压矢量脉宽调制的二极管箝位式三电平逆变器的工作情况进行了介绍,针对此逆变器在实际使用中电容电压不平衡的问题进行了分析,提出了利用检测直流侧电容电压差值和中点电流瞬时值进行滞环控制以切换两个等效的矢量作用脉冲序列来使电容电压达到平衡的方法.实验结果表明,此方法可以有效地抑制电容电压不平衡的程度,使电容电压不平衡度在2倍滞环环宽以内.器件开关损耗和开关频率比较低且调制方法较简单、易行,具有一定的实用价值.
展开▼
