Hybrid railway power conditioner with partial compensation for rating optimization

The traction power supply system using singlephase traction transformer was widely used due to its low cost and simple structure. However, more heavy-loading high-speed trains are put into use. Railway power conditioner needs to be installed to increase the loading capacity of the substation and to improve the supply quality. A hybrid railway power conditioner (HRPC) is applied to the traction substation, which can reduce the reactive power, release the system unbalance and suppress the harmonics. The HRPC was originally proposed for the cophase traction power supply system with the advantage of low voltage rating, which is only 70% of the conventional railway power conditioner. Based on the system modeling, the partial compensation is introduced to further decrease the rating of the HRPC. A comprehensive design procedure is proposed for the HRPC with partial compensation for rating optimization. A reduction of more than 50% is achieved in the HRPC rating by compensating the power factor at the grid side to 0.95 instead of unity. The control block diagram is modified for the HRPC with partial compensation. The design and control of the HRPC are validated by simulation and experimental results.