Reseach Of Low Temperature Waste Heat Power Generation Inverter System Based On ORC

The low-temperature waste heat power generation technology can be used to recover geothermal,solar heat,industrial production of waste heat and other forms of low-grade thermal energy to generate electricity.If the waste heat energy is fully utilized,it will save a lot of resources for the community,but also reduce pollution.With the increasing contradiction of energy,waste heat power generation technology has gradually been the concern of scholars at home and abroad.The low temperature waste heat power generation technology based on organic Rankine cycle(ORC)is the main form of low temperature waste heat power generation,in this paper,power generation,inverter problems based on the technology were studied,the main contents of this paper are as follows:Firstly,this paper introduces the composition and operation principle of low temperature waste heat power generation system,and models and analyzes permanent magnet synchronous generators and inverter systems,which is the system core components.then it analyzes mathematical model of permanent magnet synchronous generator to obtain the equation of voltage,flux and torque in the model;It analyzes the decoupling process of three phase inverter and the harmonic characteristicsis before filtering,and deduces the small signal model of the inverter system and inverse system transfer function under bipolar SPWM modulatio.The above work lays the foundation for ORC generator electromagnetic design and inverter loop design.Secondly,this paper makes electromagnetic design for the generator of ORC low temperature waste heat power generation,and completes the prototype trial and experimental study.Permanent magnet synchronous generator has some advantages of high efficiency,high power factor and high power density characteristics compared to other motors,so this system uses it as an expander drive motor for power generation,it can improve the efficiency of the system and system power density in the whole to avoid the waste of energy consumption.Then,according to the performance requirements and size limitations of the entire power generation system for the generator,make electromagnetic design of the motor based on Ansoft electromagnetic simulation.Finally,this paper completes the prototype trial and accomplishes experimental research.Thirdly,this paper designs the filter parameters and feedback loop for low temperature power generation inverter.It analyzes the output voltage harmonic characteristics of bipolar SPWM modulation,designs the filter parameters to reduce the Total Harmonics Distortion(THD)of the output voltage;The unstable output of the generator or load side sudden increasing in load will cause the impact of the system,result in serious system collapse.In this paper,the whole inverter system is modeled firstly and the voltage and current double closed loop are designed in the continuous time domain,afterward discretized it to obtain the parameters of the regulator in the digital system,the system has faster dynamic performance and higher output accuracy through this way.The simulation analysis of the whole inverter system is completed to verify the superior dynamic response and steady state performance of the system under the condition of load mutation and power supply voltage disturbance.Simulation shows that the system voltage regulation and load regulation rate is well,the inner loop can quickly suppress the power and load fluctuations,thus maintaining the output voltage stability.Finally,the influence of the perturbation of the variables on the system output is analyzed by the establishment of the system transfer function.Finally,this paper sets up the overall experimental platform,and carries out experimental research.It sets up a low-temperature waste heat power generation system experimental platform and writes software program.The hardware mainly includes the selection of the power device,the selection of the driving circuit,the selection of the LC filter parameter and the selection of the DC side capacitor.The software includes the main program,PWM cycle interrupt subroutine and the fault handling subroutine,those subroutine’s function respectively is to complete the DSP system initialization settings,the completion of signal sampling and processing and achieving control algorithm,and the judgment and processing of the hardware and software fault signals.The efficiency of the inverter and the operating efficiency the whole ORC power generation system is tested,experiments show that the design of the motor and inverter system has good performance,and can meet the requirements of ORC low temperature power generation.