Constant Effective Duty Cycle Control for Flying Capacitor Balancing in flying Capacitor Multi-Level Converters
Constant Effective Duty Cycle Control for Flying Capacitor Balancing in flying Capacitor Multi-Level Converters
复制标题
快速电容器多电平转换器中快速电容器平衡的恒定有效占空比控制
作者：
Andrew Stillwell;Enver Candan;R. Pilawa
利用飞跨电容多电平（FCML）转换器的挑战之一是飞跨电容平衡。平衡不良的飞跨电容会增加开关电压应力，这对性能和器件额定值要求是不利的。先前，谷值电流检测被示出为平衡飞跨电容器的潜在方法，但是该方法在轻负载下具有差的飞跨电容器平衡性能。在这里，我们调查轻负载条件下，导致平衡不良，并提出了一种新的方法，恒定有效占空比（CEDC）补偿，它提供了转换器的全负载范围内的主动平衡。所提出的方法进行了验证与4级FCML实验样机，表现出良好的飞跨电容平衡在所有负载范围内，并在多个感应飞跨电容不平衡。
One of the challenges of utilizing Flying Capacitor Multi-Level (FCML) converters is the flying capacitor balancing. Poorly balanced flying capacitors increase the switch voltage stress, which is detrimental to performance and device rating requirements. Previously, valley current detection was shown as a potential method to balance flying capacitors, but the method suffers from poor flying capacitor balancing performance at light load. Here, we investigate the light load conditions that lead to poor balancing and propose a new method, constant effective duty cycle (CEDC) compensation, which provides active balancing for the full load range of the converter. The proposed method is validated with an 4-level FCML experimental prototype, demonstrating excellent flying capacitor balancing over all load ranges and across multiple induced flying capacitor imbalances.