Single‐phase current source converter with high reliability and high power density

Abstract

For single-phase current source converter (SCSC), at least one upper device and one lower device have to be gated on and maintained at any time. Otherwise, an open-circuit of the DC-link current would occur and destroy the devices. In addition, a bulky DC-link inductor is usually required to obtain a smooth DC-link current. To address these issues, this study proposes a novel SCSC with high reliability and high-power density. In the proposed circuit, even all the switches are turned on or turned off simultaneously, neither short-circuit nor open-circuit will happen. The inductance in DC-side is reduced significantly byadopting the active power decoupling technique. First, the operation principle of the proposed converter is introduced in detail. Then, a closed-loop control method is presented to regulate the DC-link current, maintain the DC component of the decoupling capacitor voltage, and achieve sinusoidal grid current. Besides, the parameter design of the circuit and controller is investigated. Moreover, the efficiency comparison between the proposed and other SCSCs is carried out. Finally, the effectiveness of the proposed topology is verified by the experimental results.