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Novel switched link pulse-width-modulated (PWM) current source converters are presented. These converters supply a controlled dc current to the load with a concurrent elimination of selected harmonics in the ac mains. The new topologies permit minimal constraints to be formulated resulting in significantly more efficient PWM patterns than hitherto reported in the literature. A higher number of harmonics are thus eliminated at the mains for a given switching frequency while maintaining a control capability of the output dc current in a wide range. Simulation results confirm the theoretical findings. Also discussed in the paper is the selection of capacitor filters to mitigate the residual harmonics. Index Terms--Amplitude modulation, current source converter, harmonic elimination, pulsewidth modulation.

Passive damping is the most adopted method to guarantee the stability of LCL-filter-based grid converters. The method is simple and, if the switching and sampling frequencies are sufficiently high, the damping losses are negligible. This letter proposes the tuning of different passive damping methods and an analytical estimation of the damping losses allowing the choice of the minimum resistor value resulting in a stable current control and not compromising the LCL-filter effectiveness. Stability, including variations in the grid inductance, is studied through root locus analysis in the z-plane. The analysis is validated both with simulation and with experiments. [ABSTRACT FROM AUTHOR]