The True Unity Power Factor Converter for Basic Oxygen Furnace Charging Cranes

Large charging cranes are used to introduce hot metal into the basic oxygen furnace through the use of induction motor drives for the main and auxiliary hoist. These motor drives shall have the capability of dealing with bidirectional power flow due to the action of lifting (motoring) or lowering (regenerating) the load. The use of the active rectifier increases the energy efficiency since the braking energy is not lost in heat. This article proposes a true unit power factor converter with a common dc bus and compares it to an existent solution. Theoretical analysis, simulation results, and losses calculation show the advantages of the proposal in terms of power quality, energy efficiency, and reliability. Hardware-in-the-loop results show the proper work of the developed control system.