The Variable Frequency Control Of Marine Sea Water Pump And Energy Saving Study Of System

Due to the traditional marine main sea water pump long-term worked in fixed frequency mode. The cooling water system of ship is taken as the object of study in this thesis, and in-depth analysis and research on the heat load of cooling water system, piping and related equipment. And to establish the heat load relationship module between marine engine, coolers, sea water pump and pipes on this basis. According to the heat load requirements obtain required speed of sea water pump and designing frequency control of sea water pump based on direct torque control system, and completing simulation verification and designing of software. At last, completing the research and analysis of energy saving.The main study of the paper has four parts.Firstly, the thermal load model of main engine,coolers, pipes and seawater pump is established according to the change on heat load of main engine and sea water temperature in this paper. Getting the pump real speeds according to different thermal load and different sea water temperature. Then analysis the sea water pump motor. For the convenience of modeling and analysis of calculation, built in the two-phase stationary coordinate of induction motor by coordinate transformation., the direct torque control theory applied to sea water pump motor for frequency control, through the stator flux magnitude and direction control and regulate torque and speed of the motor.Nextly, establish related simulation modules of main engine heat load simulation models, coolers, pipes and seawater pump and the simulation models of direct torque control system, including:flux, torque observation module, the section judging module, torque, flux regulator model. under the premise of ensuring the system cooling capacity to meet the required heat load, through direct torque control to achieve frequency control of main sea water pump, according to different heat load of main engine and sea water temperature to adjust the speed of sea water pump, the modeling and simulation of whole system were completed by using MATLAB/Simulink software, and the results were analyzed.Then, based on C# language in the Visual Studio 2010 development platform design and develop system simulation software, which can be implemented in different factors and in different modes, the main seawater pump can be manual or automatic started and stopped according to the cooling requirement of the system, the software also can monitor the real-time important parameters, such as temperature, speed, flow and so on.In the end of the thesis, the simulation results is energy calculated under different conditions.The results show that this system can adjust the speed of seawater pump automatically according to the different thermal load of main engine and different seawater temperature based on direct torque control, which reduces energy consumption effectively compared to running in frequency mode of sea water pump and save energy consumption effectively, therefore taking a substantial step to green ship, saving ship.