Phase-shifted diode rectifier (PSDR) can effectively reduce harmonic content in AC systems. It is a solution for achieving low-cost and light-weight design of deep-sea wind power sending systems owing to its significant capability to reduce even eliminate AC filters. This paper investigates the harmonic emission mechanism and propagation characteristics of PSDR-based sending systems. Firstly

physical mechanism of harmonic emission is fully analyzed by the method of positive/negative sequences harmonic phase-shifting

and the factors and laws influencing on the emission characteristics are clarified. Secondly

frequency-domain model of harmonic propagation via offshore AC-grid is established to identify the harmonic distribution pattern between PSDR and wind farm sides. Finally

theoretical findings are validated by simulations and experiments

which demonstrates the effectiveness of low harmonic operation. The study provides valuable reference for PSDR topology design and wind turbine converter optimization.