Dsp-based Gas Engine And Control System And The Instantaneous Speed Analysis

Research of natural gas engine appears after energy shortage and environmental pollution in the world. Because the natural gas is a kind of economic clean fuel and there are abundant natural gas resources in our country, developing the natural gas engine can fully utilize domestic resources, reduce the reliance on the international energy, and has a bright future. It is an important subject that electronic control system of natural gas engine is being researched. The traditional electronic control system uses MCU and computer together which has a low speed and poor real-time character. With the fast development of digital signal processor, DSPs are playing an important role inmaking the performance of the electronic control system more perfect-high speed,low power consumption and good real-time instead of MCU. This system is just one of natural gas engine electronic control system based on DSP.The system mainly consists of DSP-the control core, into which we move theadvanced fuzzy control algorithm, advanced channels, executive parts, man-machine interfaces and power etc. It is a stable and high reliable negative feedback system which can control the ignition moment and energy of the natural gas engine to generate electricity.This paper introduces the primary principle of the natural gas engine control system, puts forward a whole design idea, and gives the system structure . It still introduces the central control part of the system and important peripheral circuits and discusses the fuzzy control algorithm, software design and the realization on the hardware platform.The system selects the popular digital signal processor DSP-TMS320LF2407as the control center. This chip is one of the c2000 products apt to industry control produced by American TI company whose products are 44% of the total DSP products in the world. It has low power consumption, high executive speed, strong real-time control ability, and includes 41 I/O interfaces,2K RAM,2.5K RAM,DARAM,32K FLASH and A/D functional parts. This paper compares DSP with MCU, analyses theadvantage of the DSP such as buses structure, pipelines and repeated operations, and introduces the CPU and memory structure of TMS320LF2407 in detail.The paper introduces important circuit of the system------advanced channels unit,executive unit, man-machine interfaces unit and power unit. The advanced channels circuits are made up of revolution speed sensors, temperature sensor and preprocessing unit which can gather the important signals of revolution speed and temperature which will be amplified and shape-lifted before entering into DSP; the executive unit are the circuits which will be adjusted after DSP computes according to the inputs; the man-machine interfaces unit includes key, led, and warning circuits; the power unit supplies three different voltages to the system.The system still includes control scheme and programming. The paper designs the fuzzy controller according to the fuzzy rules acquired by the signals of revolution speed and temperature, control the input volume of the natural gas, make the fuel fired completely, to make the engine function most perfect. The software includes init module, starting module, gathering module, control module and man-machine interfaces module.The paper gives the system program flow chart and presents the simulation environment and the possible problems during programming.The whole control system is consisted of all the above.The paper finally compares the transient revolution speed curves of the natural gas engine by FIR filtering and IIR filtering, figures out the fit filtering and experiment method for the transient revolution speed, and does some research before moving the algorithm of the faults diagnosis by transient revolution speed into DSP later.The DSP technology is getting a rapid development now, and has been applied to fields of information processing,communication and industry control extensively. This system will became another convincing instance of DSP successful application in electric power industry. It will accelerate DSP application in electricity field, bring better economic benefits for the society and the country, and put forward the development and progress of the society.In another hand, there have been much research about the engine fault detection by transient engine speed and then a lot of achievements, but the research is still a beginning work and it is necessary to do more. The thesis discusses the best filter apt to the transient speed of the natural gas engine, and shows the simulations.Further research should be proceeded due to the limitation of time and ability.