Estimation of Technical and Economic Efficiency of Using the Supercapacitors in a Frequency-Controlled Crane Electric Drive with a Common DC Link

The paper gives a comparative analysis of crane electric drive systems with a common DC link. The work compares electric drive system with a diode rectifier and brake chopper and a system with an energy storage device. The latter includes a block of supercapacitors and bidirectional DC-DC converter and it is connected to a common DC link. The structure of the control system for energy storage device is discussed, and the features of systems simulation with a common DC link are also considered. The simulation results, that clearly demonstrate the possibilities of energy saving in a system with supercapacitors, are presented. In conclusion, on the example of a gantry crane with a hoisting capacity of 8 tons, an calculation of the technical and economic efficiency of using the energy storage system in a crane electric drive is made. With using the methodology for determining a net present value, the payback period for additional capital investments is given.