Novel Coordinated Control Strategy for Step-Up/Down Current-Source Converter

Current-source converter (CSC) is more attractive and increasingly used to occasions with higher requirements for reliability due to inherent antishort-circuit ability. In this article, we combine the CSC with dc/dc converter to adapt to lower input voltage applications. However, rational allocation of the duty cycle for each switch to achieve the target voltage output and the increase of the overall switching times brought by dc/dc converter are the major problems. The proposed coordinated control strategy can reasonably take full advantage of degrees of freedom based on the adjustment variable to achieve accurately control of grid-side current and load voltage. In addition, the dc-link current pulses according to six times grid angular frequency, which avoids using the zero vector to reduce the switching times. The experimental results show the proposed scheme can not only guarantee the power quality at grid side and precise voltage output but also avoid using zero vector.