【作者】 尹忠刚；

【导师】 钟彦儒；

【作者基本信息】 西安理工大学 ， 电力电子与电力传动， 2009， 博士

【摘要】 PWM整流器用于变频调速装置既可以实现能量的双向流动,又具有网侧单位功率因数控制、谐波含量少、动态响应快等优点,减小了对电网的污染,同时可以达到节能的效果。本文对PWM整流器的数学模型及其控制策略进行研究,采用基于Markov链的随机PWM技术减小PWM整流器的传导EMI和高频噪音,并对其混沌行为进行分析和验证；对三电平PWM整流器,研究了新型的拓扑结构、数学模型及控制策略。对三相两电平PWM整流器的拓扑结构与工作模式进行了分析,建立了PWM整流器的低频时域模型和高频时域模型；针对PWM整流器的整流状态,提出了一种基于12区间的PWM整流器双单输入单输出(DSISO)模型,将PWM整流器等效为两个与传统单相升压变换器类似的电路结构,大大简化了对PWM整流器的分析；基于该模型,推导了小信号模型,建立了三相PWM整流器从控制到输出的传递函数；对系统受到干扰时系统参数的变化进行了分析,从输入输出功率相等的角度,提出了系统参数设计需满足的条件；根据空间电压矢量调制和伏秒特性理论,提出了开关信号由两相静止坐标系到三相静止坐标系变换时的控制策略；仿真和实验结果验证了12区间DSISO模型及其控制策略的可行性。为了简化系统结构、提高系统可靠性,结合12区间DSISO模型的特点,提出了一种基于12区间DSISO模型的无交流电压传感器PWM整流器控制策略；设计了一种区间自同步控制器,它可以根据对指定物理量的判断对区间做出正确的选择；仿真结果验证了无交流电压传感器控制策略的有效性。为了解决基于12区间的DSISO模型能量不能双向流动的问题,提出了一种基于6区间的三相PWM整流器DSISO模型,仍然是基于α-β静止参考坐标系,将三相PWM整流器等效为两个单相全桥PWM整流器,该模型能够实现能量的双向流动,并对其控制策略进行了研究。完成了电阻负载条件下的PWM整流运行、电机空载条件下的能量回馈实验和电机带载条件下的能量回馈实验,实验结果验证了基于6区间DSISO模型及其控制策略的有效性。研究了Markov过程与Markov链的工作原理与特点,并对两状态Markov链和三状态Markov链进行了详细的分析；提出了一种基于两状态Markov链的PWM整流器随机PWM技术,能够使随机数均匀地分布在期望随机数的周围,并使随机开关频率分布更加均匀,从而使输入电流频谱分布更加均匀,减小了PWM整流器的传导EMI和高频噪音,而且与常规随机PWM相比,输入电流的纹波明显减小,该方法有效地解决了常规随机PWM技术产生的时域与频域之间的矛盾。仿真和实验结果验证了算法的有效性。研究了三相三电平PWM整流器的新型拓扑,分析了四线制三桥臂非对称三电平PWM整流器和三相两桥臂中性点二极管箝位PWM整流器的数学模型和工作模式。对于三相两桥臂三电平中性点二极管箝位PWM整流器,系统分析了数学模型和工作模式,针对其PWM整流状态,提出了一种基于12区间的DSISO模型,在两相静止坐标系中将三相两桥臂三电平PWM整流器简化为两个与传统单相升压变换器类似的电路结构。根据空间矢量调制和伏秒特性理论,分析了各开关信号由两相静止坐标系到三相静止坐标系变换时的控制策略。通过仿真结果验证了三相两桥臂三电平PWM整流器及其DSISO控制策略的有效性。基于三相两电平PWM整流器的6区间DSISO模型,以混沌动力学理论为基础,采用相空间重构法对PWM整流器的非线性特性进行了深入研究,依据相图法和绘制功率谱进行定性混沌分析,对单变量的时间序列求取最大Lyapunov指数和关联维数进行定量混沌分析。通过分析、计算和仿真,验证了PWM整流器具有典型的混沌特征。更多还原

【Abstract】 The PWM rectifier can be applicated to the frequency control system to implement bi-directional power flow, for its advantages of unit power factor control, low harmonics and fast dynamic response. It can not only reduce the harmonic pollution to the power line, but also save enegy. The mathematical model and control strategy of PWM rectifier are studied in this paper, the random PWM technology based on Markov chain is used in order to reduce the high-frequency noise and electromagnetic interference of PWM rectifier, and its nonlinear phenomenon is analyzed. The circuit topology, mathematical model and control strategy of PWM rectifier are studied for the three-level PWM rectifier.The topology and working modes of three-phase two-level PWM rectifier are analyzed, and the low-frequency time-domain model and the high-frequency time-domain model are established. For the rectifying state, a novel dual single-input single-output (DSISO) model based on twelve intervals is proposed. In this model, the a-axis model andβ-axis equivalent model are shown to be similar to two traditional single-phase boost converters, which is much easier to analyze three-phase PWM rectifier. Based on this model, the small signal model is derived, the control-to-output transfer function is deduced, and a detailed analysis of the parameter conditions required for system stability is presented. Meanwhile, the control strategy is analyzed to determine switching control signals in a switching period. Simulation and experimental results confirm the validity of the DSISO model and its control strategy. In order to simplify the system structure and increase reliability, a novel control strategy without AC voltage sensors based on the twelve interval DSISO model for the PWM rectifier is proposed. An interval self-synchronous controller is design, and the interval can be selected correctly according to the assigned physical quantity. Simulation results confirm the validity of the control strategy without AC voltage sensors.In order to sovle the problem of unidirectional power flow for the DSISO model based on twelve intervals, a DSISO model based on six intervals is proposed, and the three-phase PWM rectifier is equivalent to two single-phase full-bridge PWM rectifiers, which can implement bi-directional power flow. Based on the DSISO model and space vector modulation, the control strategy is analyzed to determine switching control signals in a switching period. The resisitor experiment, motor experiment without load, and motor experiment with load are carried out, and the experimental results confirm the validity of the DSISO model based on six intervals and its control strategy.The work principle of Markov process and Markov chain is studied, and the two-state Markov chain and three-state Markov chain are analyzed in detail. A novel random PWM technology of PWM rectifier based on two-state Markov chain is proposed, and the random cycle values can be evenly distributed around the cycle expectations. And therefore, the input current spectrum is also distributed evenly and the high-frequency noise and electromagnetic interference of PWM rectifier are reduced. Compared to the conventional random PWM, the input current ripples are reduced. The new algorithm solves the contradiction between time-domain and frequency-domain caused in the conventional random PWM. The simulation and experimental results verify the validity of the novel algorithm.The novel topologies of three-level PWM rectifier are studied, and the mathematical model and working modes of four-line three-arm three-level NPCPWM rectifier and the three-phase two-arm three-level NPC PWM rectifier are analyzed. For the three-phase two-arm three-level NPC PWM rectifier, a novel DSISO model based on a-P stationary reference frame is proposed, in which the a-axis andβ-axis equivalent model are shown to be similar to two traditional single-phase boost converters. Switching strategy is analyzed to determine switching control signals in a switching period based on space vector modulation and volt-second characteristic. The simulation results verify the validity of three-phase two-arm three-level PWM rectifier and its DSISO control strategy.According to the DSISO model based on six intervals, the nonlinear characteristics of PWM rectifier are studied in detail with phase-space reconstructing algorithm. Quantitative chaos analysis is implemented by phase graph and power spectrum, and qualitative chaos analysis is implemented by calculating the maximum Lyapunov exponent and correlation dimension. By analysis, calculation and simulation, the chaotic characteristics of PWM rectifier are verified.更多还原