【作者】 刘秀翀；

【导师】 张化光；

【作者基本信息】 东北大学 ， 综合电气化及其自动化， 2009， 博士

【摘要】 电力变换技术融合了电力电子学和控制理论,通过有效控制电能转换过程,改变电能形式,为利用新能源和提高供电质量奠定基础。在电力变换技术中,电力变换过程控制是提高电力变换性能的关键,因此电力变换过程控制一直是研究的热点。本文在分析电力变换结构特征的基础上,对电力变换过程中系统运行规律进行研究,论述了针对交流-直流-交流电力变换过程的控制方法。主要工作如下：1、针对交流-直流电力变换过程,借鉴系统能量决定系统行为的观点,提出了基于能量平衡的功率控制方法。该方法以三相整流结构在dq两相同步旋转坐标系中的数学模型和电力变换过程中交直流两侧功率关系为基础,分别控制瞬时有功功率跟踪动态参考有功功率和控制瞬时无功功率收敛于零,实现输出电压稳定和高功率因数的目标。同时该方法通过设计负载电流补偿,消除了直接功率控制中构造参考有功功率方法所引入的稳态误差。2、针对交流-直流电力变换过程中负载不确定的特点,提出了针对三相PWM整流结构的自适应控制方法。该方法通过对负载参数的自适应评估和系统能量关系,求取三相电流的动态基准,并控制三相电流和电流动态基准共同收敛,实现了输出电压的无差控制和高功率因数。在负载评估设计中,该方法突破了负载为正值的限制,拓展了系统的应用范围。3、针对直流-交流电力变换过程,采用四桥臂逆变结构,提出了通过第四桥臂对负载产生的不平衡因素进行全补偿的控制方法。该方法遵循第四桥臂电流跟踪三相负载电流负和的原则,分解四个桥臂的控制功能,揭示了四桥臂结构控制的本质,并充分利用四桥臂结构特征,完全发挥出第四桥臂调节三相输出平衡的作用。4、针对四桥臂逆变过程中负载不确定条件下三相电感电压的补偿问题,.提出了综合补偿控制方法。该控制方法以第四桥臂补偿负载不平衡因素为基础,采用三相桥臂平衡补偿控制模式。在闭环控制的设计中,通过对控制结构的巧妙构造,以积分算法代替微分算法,使控制器的设计更具实用性。5、针对直流-交流电力变换过程,采用单相全桥逆变结构,提出了基于空间矢量调制的闭环控制方法。该方法突破传统的一维控制模式,构造出二维矢量工作平面,并以二维矢量工作平面上桥臂电压、系统输出电压、电感电流的几何关系为基础,设计闭环控制,充分发挥了空间矢量调制方法在减少开关损耗和缓解输出高次谐波方面的优势。6、针对单相全桥逆变过程中负载的不确定性,提出了基于状态反馈和前馈补偿的控制方法,消除了负载不确定对系统输出波形所产生的影响,同时基于使系统稳定的实际控制能力,设计控制参数。7、指出交流-直流-交流电力变换过程控制研究中存在的问题,并对下一步研究工作进行了展望。更多还原

【Abstract】 Power conversion technology, which combines power electronics and control theory, can change electric power from one form to another by controlling power conversion processes, and therefore power conversion technology is the foundation of utilizing new energy sources and improving the quality of power supply. In power conversion technology, the control of power conversion processes is the key of improving the performance of power conversions, so the control of power conversion processes is a hot research topic. Based on analyzing the topological structure of power conversions, we focus on studying the rules of the system operation in power conversion processes and discuss control methods for AC-DC-AC power conversion process.The main research work is as follows:1. Referring to the idea that the energy decides system behavior, a power control method based on power balance theory is proposed for AC-DC power conversion process in this dissertation. According to the mathematical model of three-phase rectifiers in the synchronous dq coordinates system and the power relation of AC and DC sides in power conversion process, the proposed control scheme controls the instantaneous active power on the track of referenced dynamical active power and the instantaneous reactive power to zero, and therefore steady output voltage and high power factor is realized. In addition, the compensator for the load current is designed and the output error which is introduced from constructed referenced active power in direct power control strategy is avoided in the proposed scheme.2. Concerning with the uncertain load condition in AC-DC power conversion process, an adaptive control scheme is proposed for three-phase PWM rectifiers in this dissertation. According to the adaptive estimate of the load parameter and the relation of the system energy, the proposed scheme constructs dynamic reference curve for three-phase current. Then the proposed scheme makes three-phase current and dynamic reference current convergent together, and therefore zero output error and high power factor are realized. The restriction that loads should be positive is broken in the adaptive parameter estimator, so the proposed scheme extends the extent of application. 3. A control method based on compensating unbalanced effect completely by the fourth leg is proposed for DC-AC power conversion process using four-leg topology. The proposed control method follows the rule that the sum of four legs current is zero and discovers the essence of the control law for four-leg inverters by analyzing the functions of four legs. In addition, the proposed control method exerts the function of the fourth leg to compensating unbalanced effect according to four-leg topology.4. To compensate voltages of three-phase inductors under uncertain load conditions, a unique integrated control strategy is proposed in this dissertation. Based on compensating unbalanced effect by the fourth leg, the proposed control strategy compensates symmetrically three-phase output voltages. In addition, the proposed control method uses the integral current instead of the differential current as the control variable in order to make controller practical.5. A closed loop control scheme based on SVM is proposed for DC-AC power conversion process using single-phase full-bridge topology. In the proposed scheme, traditional control mode on 1-DOF space is breaken and a 2-DOF vectors plane is structured. Based on the geometrical relation of leg voltage, output voltage and the inductance current on the 2-DOF vectors plane, a closed loop controller is designed. The proposed scheme makes full use of the ability of SVM to lessen switching losses and mitigate harmonic.6. Concerning with the uncertain load condition in power inversion process using single-phase full-bridge topology, the control schemes based on state-feedback and feedforward compensation is proposed. The proposed schemes eliminate bad effect on output waveform under uncertain load conditions. In addition, the control parameters are designed based on the stabilization and the control capability of the system.7. Some unsolved problems in the research and the application are indicated, and the prospects are presented.更多还原