Research On Thermo-mechanical Conversion Efficiency Of Low-temperature Waste Heat System Based On Permanent Magnet Generator

With the development of modern society and technology,it leads to the rapid need ofthe international energy.According to some statistics,the heat of low-temperature accountsfor more than50%of all the industry heat.Therefore,the Organic Rankine Cycle powergeneration causes more and more studying.This technology can increase the conversionefficiency of energy,decrease the essisions of greenhouse gas,and it also has the advantegeof simple structure and high efficiency.This paper focuses on the analysis of the Organic Rankine Cycle power generationsystem and its key components,builts the experimental platform of the ORC and collectsthe experimental data. This paper mainly researches as follows:1.Generalize the principal of the ORC system and its thermo-dynamicmodel,introduce the property of R600a；study and analyze the key component:the expanderand the permanent magnet synchronous generator(PMSG).Study expander’s workingprincipals,mathematical models and all kinds of the factors which influence itscharacteistics;analyze the PMSG’s characteristics and the efficiency control.2.According to the vector control of PMSG,the space vector modulation of MatrixConverter(MC) is applied to control PMSG.In order to control the electro-magnetic torqueof PMSG, the inductor is connected to the three-phase terminal side of PMSG.Based on therequirements of the waste-heat power generation system,the block diagram of PMSGvector control system is built.The model of the system is established and the simulation istaken with Matlab software.The simulation and experimental results show that it ispractical and feasibile to complete the vector control of PMSG based on the MC.The entirecontrol system enhances the output power of the expander,and improves thethermo-mechanical conversion efficiency of the low-waste heat power generation.3.Build the main control circuit,including: the MPPT system,the BOOST circuit,thedesigning of power device and its inductance and capacity. 4.Establish the ORC experiment system,analyse the results of the expander.Atlast,analyse the results of the entire system,mainly including:the mass flow rate,the outputpower,the PMSG speed,the frequency and others,the curve shows that there is a maximumdata between the output power and the PMSG speed.