Study And Design On The Main Circuits Of Hybrid Power Rubber Tired Gantry Crane System

Nowadays energy saving and environmental protection is not only the demand of sustainable development, but also the direction of construction machinery and equipment. As energy shortage and environment problem are increasing outstanding, energy saving and environment protection become a hotspot of the scientific and technological development.As a typical port crane, rubber tired gantry crane handle loads with heavy weight and high height, lifting and laying down frequently. At the same time, the gravitational potential energy of the loads is consumed by resistance and can not be recovered in the traditional rubber tired gantry crane. If we reclaim the regeneration energy that the crane forms in the process of dropping, and take full advantage of the recovery of renewable energy supply as the driving force, recovery room will be great. Therefore we can conclude that energy consumption of rubber tired crane is huge and potential of energy saving is favorable.Hybrid power rubber tired gantry crane system uses stored energy component to recover gravitational potential energy during the process of laying down loads, and provides energy when the gantry crane starts and the loads are heavy, which will greatly improves the system performance. Because of the rubber tired gantry cranes' characteristics, we use Super Capacitor with huge capacity and can be charged and discharged quickly as energy recovering unit, which can overcome the slow charging and discharging and small capacity of traditional storage battery. It can meet the requirements of Hybrid power rubber tired gantry crane system.This composition of Hybrid power rubber tired gantry crane system are DC generators, Super Capacitor, braking resistor, filter capacitor and electric motor. We connect them by Power Electronic Circuits. In order to meet the requirements of control system, we design the DC-DC Chopper which can control the speed of motor and also reclaim the regeneration energy that the crane forms in the process of dropping. This DC-DC Chopper is the three-quadrant Motor Speed Regulator, which is developed from H-bridge Chopper Circuit. The other key part of the main circuit is the bidirectional DC-DC Converter. It is used to control charge/discharge of Super Capacitor. We use direct connection circuit as the DC-DC Converter. And the Triple Directional DC-DC Converter is analyzed in this paper. On this basis, we design the snubber circuit for the Power Electronic Devices, and also discuss an optimal control strategy for the system.The experiment of Hybrid power rubber tired gantry crane system is divided into two stages. Firstly, we get the voltage waveform and current waveform to analyze dynamic process of the main circuit, and prove the security and reliability of the system. Secondly, energy flow and losses during lifting and laying down periods are analyzed, also the principle program and specific control strategy are introduced. According to experimental data, we calculate the energy efficiency ratio of Hybrid power rubber tired gantry crane system.