基于DSP的气发动机测控系统与瞬时转速分析

【作者】 袁华；

【导师】 张卫宁；

【作者基本信息】 山东大学 ， 信号与信息处理， 2005， 硕士

【摘要】 天然气发动机的研究是针对世界能源的日益匮乏和环境污染问题而随之产生的。天然气是一种经济保洁性燃料,而我国富有天然气资源,因此研究天然气发动机能够充分利用国内资源,降低对国际能源市场的依赖,前景非常广阔。天然气发动机电控系统的研究是其中一个重要的研究课题。传统的电控系统大都采用单片机与计算机连接实现,速度慢,实时性不强。随着数字信号处理器的飞速发展,超高速、低功耗和强实时性的数字信号处理器DSP逐渐代替单片机,使电控系统不断完善,使天然气发动机的动力性、经济性、排放性等各项性能不断提高。本文所介绍的正是一种以DSP为控制核心的天然气发动机控制系统设计方案。 本系统主要由DSP控制处理核心、前置通道、执行机构、人机接口及电源等五部分构成。该系统将自动控制理论转变为实时应用算法移入DSP,与输入、输出部分共同构成一个稳定、可靠的负反馈系统控制气发动机的点火时刻和点火能量,使发电机产生稳定的交流电。 本文阐述了气发动机控制系统的基本工作原理,提出了总体设计方案,并给出了硬件结构及实用方法。本文详细介绍了系统控制核心部件及重要外围电路,着重讨论了模糊控制算法、软件设计以及在硬件平台上的实现。 本系统采用现今强大的数字信号处理器DSP——TMS320LF2407作为硬件控制处理核心。该芯片是市场份额占全球44%的DSP厂商美国TI公司推出的适用于工业控制的C2000系列产品之一,功耗低,执行速度快,实时控制能力强。本文比较了DSP与单片机的一些特点,分析了DSP总线结构、流水线指令执行方式和重复操作机制等方面的优势,详细介绍了TMS320LF2407芯片的CPU、存储器结构等。 本文介绍了系统的其它重要硬件电路设计——前置通道电路、执行结构电路、人机接口电路和电源电路等。前置通道主要包括转速传感器、温度传感器和预处理电路,实现采集天然气发动机的转速和温度两个重要信号,并进行放大,整形等处理;执行机构为DSP对输入信号进行测算后去调整的电路部分;人机接口包括键盘、LED显示、声光报警等部分;电源电路向整个系统分配了3组不同的电压,以满足系统需要。更多还原

【Abstract】 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.更多还原