【作者】 闫士杰；

【导师】 王旭；

【作者基本信息】 东北大学 ， 检测技术与自动化装置， 2010， 博士

【摘要】 微型燃机发电系统是一种新型能源发电系统,具有清洁、可靠、多用途等优点,应用于分布式发电系统和冷热电联供系统,以及作为备用电源、便携式电源和特种军用电源,具有广泛的应用前景和重要的研究价值。本文以国家“863”项目“100kW级微型燃气轮机研制(2002AA503020)”和“电气传动及控制系统节能技术的研发(2006AA04Z183)”为依托,研究了燃机起动、运行控制及电力变换等全过程,构造了燃机一体化控制系统,建立了燃机发电系统非线性动态数学模型,提出了基于转速的自适应模糊H∞控制。为了提高微型燃机系统电能转换质量和供电质量,提出了高频PWM整流器自适应控制策略和基于阻抗变换的三相四桥臂逆变器解耦控制策略,研制了燃机控制系统和电力变换器系统。在一体化控制方面,通过分析燃机本体结构和实现的目标,将燃机起动控制、速度控制、燃料压力控制、整流及逆变控制等整合到以燃机控制为核心的控制系统中,最后采用中央控制单元整体协调,构造完备的一体化微型燃机控制系统。通过对燃机系统的机理分析,基于能量守恒和质量守恒原则,根据燃机热力学理论和国家“863”计划项目的控制目标,推导了燃机转速、排气温度、透平入口压力、透平入口温度、压气机出口压力等关系方程,建立了基于燃机转速、透平入口压力和排气温度的系统非线性状态空间方程模型。同时,针对微型燃机内的一体化永磁同步发电机,建立了dq0坐标系下的电压方程、磁链方程、电流方程、电磁转矩方程、运动方程和功率方程。在燃机控制方面,为抑制因一体化控制时带来的电磁干扰,在速度给定和反馈通道上,嵌入了跟踪微分器。针对电磁干扰频率可测和幅值有界的特点,应用线性函数代替非线性饱和函数,重新构造了快速的跟踪微分器,从而进一步减小了跟踪延迟。由于燃机动态模型非常复杂,且存在很大的不确定性,所以本文提出了燃机转速的自适应模糊H∞控制策略,应用线性矩阵不等式控制技术,在李亚普诺夫稳定意义下设计了自适应模糊PID控制器以及在线自适应调节的鲁棒H∞控制补偿项,以减小模糊逼近误差和外部干扰对控制性能的影响,保证了闭环系统的稳定性和跟踪性能。仿真研究结果表明,应用提出的复合控制方案对抑制电磁干扰和转速跟踪都取得了良好的控制效果,具有很好的实时性,易于工程上的实现。在PWM整流器控制方面,通过分析PWM整流器的工作原理和基于永磁同步发电机模型,建立了PWM整流器模型,对系统进行了功率控制。考虑微型燃机发电系统容量小,受负载波动影响大,以及负载不确定性的特点,在功率控制的基础上,提出了直流侧电压自适应H∞控制方案,在李亚普诺夫稳定意义下,通过自动补偿负载变化,实现直流侧电压稳定和高功率因数。仿真结果验证了所提方案的有效性和实用性。在三相四桥臂逆变器控制方面,提出了基于内阻变换的三相四桥臂解耦控制策略。主要将逆变器和其输出滤波器作为一体化逆变电源,进行一体化建模和一体化控制。经过等效变换,将零线桥阻抗值变换为零,将其它各相的阻抗等效地降为较低的阻抗值,将其解耦成三个相互独立的单相逆变器。这样就将三相四桥臂逆变器控制控制问题转化成了单相逆变器控制问题。控制方法上,采用幅相多环控制,这样不但能使逆变电源独立运行,也能通过跟踪电网的频率进行并网运行,完全发挥出了四桥臂逆变结构的优势,特别是对不平衡和非线性负载具有良好的控制能力。仿真结果验证了该控制方法的正确性和有效性。最后,对微型燃机控制系统、PWM整流器和三相四桥臂逆变器分别研制了样机,在100kW微型燃机发电机组实验平台上进行了实验研究,对燃机系统的起动、点火、加速、脱机和发电等全过程进行了实验。从实验数据和实验波形看,一体化控制系统及其控制策略达到了预期效果。更多还原

【Abstract】 Micro-turbine generator (MTG) is a novel power generation system, whose main advantages are clean, reliable and multipurpose. MTG is applied in the fields such as distributed power generation systems, combined cooling-heating systems. Furthermore, this system can be taken as backup power supply, mobile power supply or special military high performance mini-station. MTG has great potential in application and important worth in research.Relying on national "863" project "100kW-level micro-turbine development (2002AA503020)" and "research of energy-saving technology based on electric drive and control system (2006AA04Z183)", the whole process including MTG start-up, running and power conversion is studied in this thesis. The integrated control system is constructed. The nonlinear dynamic mathematical model of MTG is formulated. The adaptive fuzzy Hx control of speed is proposed. In order to improve the quality of MTG power conversion and quality of power supply, the adaptive control strategy of high-frequency PWM rectifiers and the decoupling control strategy of three-phase four-leg inverters based on impedance transformation are proposed. Finally, we developed a control system of gas turbine and an electric power converter system.With respect to the integrated control system, we integrate start-up control, speed control, fuel pressure control, rectifier control and inverter control into the gas turbine control system by analyzing the MTG structure and control goal. Finally, overall subsystems are coordinated into the central control unit and the integrated micro-turbine control system is constructed. According to the principle of energy conservation, quality conservation, gas turbine thermodynamic theory and the control objective of the national "863" project, the system relationship equations for the variables such as gas turbine speed, exhaust temperature, turbine inlet pressure, turbine inlet temperature and compressor exit pressure are derived through the mechanism analysis of gas turbine. Then, a nonlinear state space equation for turbine speed, turbine inlet pressure and exhaust temperature is described. Meanwhile, the voltage equation, flux linkage equation, current equation, electromagnetic torque equation, motion equation and power equation is established in the dqO frame for integrated permanent magnet synchronous generator in the micro-gas turbine.In the control of gas turbines, the tracking differentiator is embedded in speed reference channel and feedback channel for suppress electromagnetic disturbance due to integrated control. Since the electromagnetic interference frequency is measurable and its amplitude is bounded, the non-linear saturation function in the tracking differentiator is replaced by a linear function. A fast-tracking differentiator is re-constructed to reduce the tracking delay. As the gas turbine dynamic model is very complex and has large uncertainty, the adaptive fuzzy control strategy of speed with H∞performance is proposed via linear matrix inequality technique for MTG based on Lyapunov stability theory. At the same time, a robust adaptive compensator is derived to eliminate the effect of the approximation error and external disturbance and guarantee the closed-loop system stability and good tracking performance. Simulation results show that the proposed hybrid control strategy can satisfy the requirement of the real-time control, speed tracking and suppression of electromagnetic disturbance. It is easy to be implemented in engineering.In the control of PWM rectifier, a PWM rectifier model is formulated and a power control scheme is applied by analyzing the principle of PWM rectifier and the permanent magnet synchronous generator model. Considering the features including the small capacity of MTG system, the load fluctuation and the uncertain load condition in AC-DC power conversion process, an adaptive control H∞strategy in the sense of Lyapunov stability is proposed for DC link voltage based on the power control method. Through automatic compensation for load changing, a stable DC link voltage and high power factor can be achieved. The simulation results show that the proposed scheme is effective and practicable.In the control of three-phase four-leg inverters, decoupling control strategy of three-phase four-leg is proposed based on the internal impedance transformation. The inverter and its output filter are regarded as an integrated inverter power supply to modeling and control as a whole unit. After equivalent transformation, the impedance of zero-leg is transform into zero and the others are reduced to a lower equivalent impedance value. The three-phase four-leg inverter is decoupled into three independent single-phase inverters which can be controlled by single-phase inverter control method. In this scheme, an amplitude-phase multi-loop system is applied. Therefore, it will not only enable the inverter operate independently, but also connect to grid by tracking the frequency. Advantages of the four-leg inverter structure are exerted particularly for unbalanced and non-linear load. The simulation results show that the control method is correct and effective.Finally, the prototypes of MTG control system, PWM rectifier and three-phase four-leg inverter are developed respectively. In the 100kW MTG experimental platform, experiments are carried out in the whole process of power generation including start-up, ignition, accelerating, off-line and generating. The experimental data and experimental waveforms show that MTG integrated control system and its control strategy have achieved the expected goals.更多还原