Novel Control Structures for Parallel Two-Stage Converters Based on Shared SVPWAM/SVPWM

Current-source converters are favored for their special and wide output voltage range. In order to increase power transmission, the structure and control strategies of parallel current-source converters have been developed. Meanwhile, two-stage cascaded current-source converters have an extremely wide output voltage range. However, until now, the control strategy for two-stage parallel current-source converters has not been studied. Therefore, this paper focuses on the control structure of current-source converters with this particular topology. Based on the proposed control architecture, multiple parallel current-source converters only need to use the same SVPWM or SVPWAM (Space Vector Pulse Width Modulation) (Space Vector Pulse Width Amplitude Modulation), eliminating the need for each parallel converter to use its own modulation scheme as in traditional droop control architectures. Even in the presence of differences in parameters among paralleled branches and filters, sinusoidal grid current, unit power factor, IOOOV output for the load can still be achieved. Simulation results also validate the correctness of theoretical analysis and the effectiveness of the proposed approach.