Research On Active Vibration Control Of Marine Diesel Generator Set

Vibration of the marine diesel engine power plant not only affects the safety of ship hulland the operation reliability of relevant equipments and meters, but also causes the noisepollution and harm to the surrounding environment. For the warships, the vibration willinfluence their stealth and fighting capability. Therefore, it is of great importance to controlthe vibration of marine diesel engine. For the traditional passive vibration control means,however, it is difficult to effectively isolate the low frequency vibration. Moreover, once theisolation system is determined, other characteristic parameters, such as stiffness and damping,will be also fixed, which means that the isolation system cannot track the variation of externalexcitation.Motivated by the aforementioned shortcoming of traditional passive isolation,preliminary engineering studies have been performed on the real ship with its diesel generatoras the investigation object. The engineering design of actuator and controller, which are thebottle neck problems in the restriction of active vibration control practical application, arediscussed and investigated in much depth. One type of sensor integrated inertial actuator hasbeen developed with the spring piece as the suspension spring. The controller special for thereal ship application is designed and made. Experimental studies are also performed for thedesigned actuator and controller. In the laboratory environment, the simulation and setupstudies are carried out for the vibration characteristics of the marine diesel generator,including numerical calculation, measurement and analysis. The experimental investigationof active vibration control of real marine diesel generator has been conducted, and theimplementation procedure of active control of marine power plant has been preliminarilysummarized. The works completed in the thesis are given below:Based on the simulation analysis of magnetic flux density and magnetic line of force forthe actuator, the optimal design is performed for the actuator dimensions. The effects of yokethickness and magnetic conductivity outer cylinder on the magnetic induction intensity of airgap are also analyzed. Optimal structural design is also carried out for the spring piece, andexperimental study is performed to check the actuator performances.With the DSP and CPLD as the core device, the controller is designed special for activevibration controller, which is made by using the core chip. According to certain standard, the experiments have been done for the check of actuator and controller developed.Experimental setup is built up in the laboratory condition, and the structuralcharacteristics of the setup has been investigated. Then, the algorithm simulation and controlexperiments are also conducted for the active vibration control system. The results from thesimulation and experiments shows that the actuator developed can operate reliably. Thisprovides the solid foundation for the active vibration control experiments of the marine dieselgenerator sets.Modal test has been performed for the marine diesel generator sets composed by theTXF-280L4-H generator and6135diesel engine on certain tugboat, the natural property ofthe diesel engine generator set is then obtained. Experimental measurement is also performedto derive the vibration characteristics of the diesel generator set.The active vibration control experiments of the diesel generator sets have beenimplemented for the first time at home on a real ship. For the diesel generator set, the x-LMSalgorithm is used for the offline identification of the error path; the active vibration controlexperimental studies are then performed during the variation of diesel rotation speed from800r/min to1500r/min. The results indicate that active vibration control system can yieldsignificant attenuation of acceleration response to various extents for the observing points oneach isolator, with the largest vibration reduction up to6dB. Some reduction is also found atthe underwater microphone located outboard.In this thesis, the preliminary design procedure of active vibration control system hasbeen proposed based on the active vibration control experiments of diesel generator set. It isbelieved that this proposed procedure can provide help reference for the design of activevibration control of other ship power plant.