| Advances in static power conversion technology and in control of DC motors have led to increased use of electric drives in naval platforms, and the proliferation of non-linear loads. These loads inject significant harmonic currents into the shipboard power supply buses. The Canadian Maritime Coastal Defence Vessel (MCDV) makes use of DC propulsion motors and solid-state power conversion equipment to achieve its requirements for high level of propulsion control, versatility, and redundancy. During ship acceptance trials, total harmonic distortion in the 600V supply bus of 29.3% was measured in the current waveform, and 8.2% in the voltage waveform. The MicroTran analysis software package was used to construct a model of the harmonics and switching transients on the bus. The model accurately predicts the harmonic content of the supply. Subsequently, the model was used to assess the preliminary design of harmonic filters, and investigate the severity of certain transient events. |
