Dual current control scheme for PWM converter under unbalanced input voltage conditions
Dual current control scheme for PWM converter under unbalanced input voltage conditions
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DOI：
10.1109/41.793344
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发表时间：
1999-10-01
影响因子：
7.7
通讯作者：
Nam, K
中科院分区：
文献类型：
--
作者：
Song, HS;Nam, K
三相系统中的电压不平衡会在断路器中产生120 Hz的电压纹波，从而增加无功功率，从而导致脉宽调制(PWM)变流器的性能恶化。根据Rioual等人的论文，为了消除脱链电压纹波和无功的De分量，应该同时控制正序和负序电流。我们使用了两个同步参考系：正同步参考系中由比例积分(PI)控制器调节的正序电流和负同步参考系中由PI控制器调节的负序电流，在逆时针旋转的正同步参考系中，正序显示为de，而负序显示为120 Hz，相反，在顺时针旋转的负同步参考系中，负序显示为de，而正序显示为120 Hz。通过在每个SRF中使用陷波滤波器去除120 Hz分量，可以分别测量正序和负序电流，并使用它们来构造两个反馈控制器。由于负序电流也由de命令在其自身的SRF中控制，因此该方法在不增加控制增益的情况下产生更好的性能。请注意，由于控制器由数字信号处理器芯片中的软件例程实现，因此使用两个SRF不需要额外的硬件。通过计算机仿真和实验验证了该控制方案的有效性。
Voltage unbalance in a three-phase system causes performance deterioration of a pulsewidth modulation (PWM) converter by producing the 120-Hz voltage ripples in the de link and by increasing the reactive power. To eliminate the de-link voltage ripple and the de component of the reactive power, both positive- and negative-sequence currents should be controlled simultaneously, according to the paper by Rioual et al. We used two synchronous reference frames: a positive-sequence current regulated by a proportional integral (PI) controller in a positive synchronous reference frame (SRF), and a negative-sequence current regulated by a PI controller in a negative SRF, In the positive SRF, which rotates counterclockwise, the positive sequence appears as de, while the negative sequence appears as 120 Hz, In contrast, in the negative SRF, which rotates clockwise, the negative sequence appears as de, while the positive sequence appears as 120 Hz. By deleting 120-Hz components using a notch filter in each SRF, one can measure positive- and negative-sequence currents separately, and use them for constructing two feedback controllers. Since the negative-sequence current is also controlled in its own SRF by a de command, this approach yields better performance without increasing the control gain. Note that, since the controller is implemented by a software routine in the digital signal processor chip, using two SRF's does not require additional hardware. We demonstrated the effectiveness of the proposed control scheme by using computer simulation and experiments.