Research On Control Strategy Of Variable Speed Diesel Generator Set

At present,diesel-powered energy system has become a trend in the field of the world’s ships,especially the low-speed,high-power diesel engines.Because of its high reliability,large power for single machine,and good economy,it has been widely used in military vessels and large civilian vessels in recent years.Variable-speed generation technology is currently a relatively new technology,and at present,it has been widely used in automotive,aerospace power,wind power and other industries.In recent years,the introduction of variable-speed generation technology in diesel generator sets has achieved rapid development due to its excellent vibration,noise reduction,economy and low labor maintenance costs.The biggest advantage of variable-speed generation is its good fuel economy,and the fuel consumption rate of the diesel engine is closely related to its operating speed.In order to reduce the fuel consumption rate of diesel engines,the research on the optimal running speed of variable speed diesel generator sets will be one of the research focuses.Compared with the traditional constant-speed and constant-frequency power generation,variable-speed and constant-frequency power generation will be another focus of this paper because of its advantages of increasing economical operation,simple control,and greatly improving energy utilization.Firstly,in order to realize variable-speed and constant-frequency power generation,this paper studies several kinds of variable-speed and constant-frequency power generation systems and analyzes their advantages and disadvantages.And then,the brushless doubly-fed generator variable-speed constant-frequency power generation system is adopted.The basic theory of the diesel engine is analyzed and the average model is derived.The simulation verifies the correctness of the model.The basic theory of the BDFM is analyzed and the mathematical model based on the rotor-speed coordinate system and the stator-speed coordinate system is derived.The correctness of the mathematical model is verified by simulation.Secondly,this paper studies the diesel engine control system based on the optimal operating speed.The optimal running speed of the variable speed diesel engine will be analyzed,and the optimal running speed curve will be designed.The adaptive fuzzy PID controller is analyzed and researched,and the adaptive fuzzy PID controller is designed,and the adaptive fuzzy PID controller is compared with the conventional controller.The speed feedback-load feedforward controller is analyzed and researched,and the speed feedback-load feedforward controller is designed,then the speed feedback-load feedforward controller is compared with the conventional controller.The adaptive fuzzy PID controller and the speed feedback-load feedforward controller are analyzed comprehensively to verify the advantages of the speed feedback-load feedforward controller in the diesel engine speed control system.Furthermore,this paper analyzes and studies the mathematical model and control method of the grid side converter.It adopts the grid voltage vector orientation control method to realize the decoupling control of the active and reactive power system.It designs double closed loop regulator to the voltage and current by engineering design method.Through modeling and simulation,the correctness for the mathematical model of the grid-side converter and the adjustment parameters of the regulator is proved by changing the cross-axis component of the grid current.Finally,this paper analyzes the control-side converter of the BDFM.The control strategy of single machine power generation for BDFM is studied.The correctness and accuracy of the control strategy for single-machine power generation of BDFM are verified by simulation.The control strategy grid-connected power generation for BDFM is studied.The correctness and accuracy of the control strategy grid-connected power generation of BDFM are verified by simulation.