Sequential Switching Shunt Regulator With Improved Controller to Suppress the Influence of Double-Section Phenomenon

The double-section phenomenon is inherent to the sequential switching shunt regulator (S3R), which increases the bus ripple, affects the poststage filter design, generates electromagnetic interference, and reduces the system reliability. In this article, an in-depth study of the S3R reveals that the double-section phenomenon is caused by a combination of hysteresis loop overlap, sampling integration delay, and parasitic capacitance of the solar panel. To suppress the influence of the double-section phenomenon, according to the working characteristics of S3R, an improved controller is proposed: first, replace the ladder-shaped comparators with the ladder-shaped subtracters and then use fixed frequency control to fix the sampling ripple frequency; subsequently, the specific frequency of the sampling ripple is compensated to reduce the phase shift, thus reducing the delay of the sampling signal, and finally, the S3R’s double-section phenomenon is suppressed. The controller’s specific structure and parameter design procedure are also given in this article. Finally, the correctness and feasibility of the proposed method are proved by building an experimental prototype.