Research On Speed Control Strategy And Performance Optimization Of Variable-speed Diesel Generator Set

Power electronic technology,information control technology and motor control technology is increasingly mature,which promote the development of the DC power plant electric propulsion system to a large extent.As the same time,the energy crisis and environmental problems become increasingly serious.The ship industry,as a large energy-consuming industry,puts forward higher requirements to ship's energy-saving and environmental performance.Compared with the traditional constant speed diesel generator set,the variable-speed diesel generator set has the advantages of low fuel consumption,low noise,less pollution discharge and low maintenance cost.Therefore,the power plant of the DC power propulsion system adopts variable-speed diesel generator set.The speed of the variable-speed diesel generator set varies with the load,and its running speed and operating condition are different from the propulsion system or constant speed generator.In order to bring the advantages offuel saving into full play,this paper takes the variable-speed diesel generator as the research object,and carries out the speed control strategy and performance optimization of the variable-speed diesel generator set.The operation principle of variable-speed diesel generator set is analyzed,and the calculation models of diesel and asynchronous generator are established respectively.The calculation model of the intake and exhaust,combustion,heat transfer and supercharger of the diesel is established.The calculation model of the asynchronous generator under the dq axis coordinate is established,and the control method of the excitation and torque of the asynchronous generator is put forward,which provide the theoretical basis for simulation model of variable-speed diesel generator set.The dynamic mathematical model of the variable-speed diesel generator set is established by fitting the test data of the universal characteristics of the variable-speed diesel generator set.The optimal running speed of variable-speed diesel generator set is studied by mathematical model optimization and test data optimization,and the fuel consumption test is carried out.The result shows that the fuel consumption rate of the variable-speed diesel generator running at the optimum running speed is lower than the constant speed mode,and the optimum operation speed got from the test data is more fuel-saving.According to the operating conditions of Fuxing shipping service tug,the stepless speed control strategy,the step speed control strategy and the "step + stepless" speed control strategy of the variable speed diesel generator set are designed respectively.The corresponding security control strategy is designed.The test results show that the variable-speed diesel generator set can run according to the designed control strategy.The simulation model of variable-speed diesel generator set is established,and the performance optimization of variable speed diesel generator set is carried out,which provides the guidance for conventional generation diesel engine transforming into variable-speed generating unit.The results show that reducing the turbine cross-sectional area and adjusting the fuel injection advance anglecan improve the performance of diesel engine and reduce fuel consumption,making it more suitable for variable-speed generate set.