【作者】 肖强；

【导师】 李铁才； 杨贵杰；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2008， 硕士

【摘要】 电力电子器件及二极管整流器的广泛应用,给电网带来了大量的谐波和无功污染,而PWM整流器的出现,使得网侧电流的正弦化和功率因数控制成为可能。在电力电子技术飞速发展的今天,PWM整流器的控制技术发展仍相对缓慢,成为限制其性能发挥的瓶颈,因此论文对三相电压型PWM整流器(PWM-VSR)的控制策略进行了深入的研究,研究成果对提高PWM-VSR系统整体性能具有重要的理论指导意义和工程实践意义。论文首先对VSR的直接功率控制进行了研究,以电网的输入瞬时功率为直接控制对象,利用空间矢量原理绘制了向量开关表,采用滞环控制器实现对VSR瞬时功率的控制,并对其性能进行了仿真分析。结果表明,直接功率控制方式下瞬时功率具有较快的动态响应速度,且同时可实现电流的高度正弦化控制。其次,针对VSR控制系统中大量电压及电流传感器的使用所带来的系统成本增加和稳定性降低问题,论文对无网侧电压传感器的VSR控制策略进行了深入的研究,提出采用虚拟磁链法计算瞬时功率,并利用锁相环计算电网角度,解决了无网侧电压传感器控制系统中的关键问题。为提高系统的稳态性能,得到更加平滑的电流,论文将SVPWM技术引入到直接功率控制系统当中,对瞬时功率进行了前馈解耦,实现了基于SVPWM的虚拟磁链直接功率控制。再次,为实现对谐波电流的实时检测,论文提出了一种扩展的基于瞬时功率理论的谐波电流检测方法,使得对基波无功电流和特定次谐波电流的检测可在一个电网周期内完成。同时为实现VSR的无功补偿和谐波抑制控制,论文在分析直接功率控制局限性的基础上,提出了对谐波电流在谐波同步旋转坐标系下进行控制的方法,以实现无静差调节。最后,构建了基于TMS320F2812 DSP的系统硬件平台,编写了软件程序代码,对文中所提出的方法进行了实验验证,实验结果表明,论文所提出的控制策略正确可行,系统具有良好的动态性能和稳态精度。更多还原

【Abstract】 The widely use of power electronic devices and diode rectifier produce large quantity of harmonics and reactive power pollution. PWM rectifier has the advanced features including sinusoidal current output and controlled power factor. These features can not be achieved without applicable control technology while power electronic is increasingly developing. This paper discusses the control strategies of three phase PWM voltage source rectifier under unity power factor control and compensation control of harmonics and reactive power. The results obtained in this paper have great significance in improving the performance of PWM-VSR system.Firstly, the direct power control(DPC) strategy is studied, which operates directly to the input instantaneous power of grid. This paper makes deeply research on this strategy, plots the control switch table by principle of space vector and implements the instantaneous power control of VSR by using hysteresis controller. Simulation results show that DPC is able to perform excellent sinusoidal current and power factor control.Secondly, in order to control the cost and increase reliability of VSR system, a control strategy without ac voltage sensors which are replaced by virtual flux estimator is discussed. Moreover, instantaneous power and grid angle is calculated by the information of virtual flux using PLL, which is the key point of direct power control. The introducing of SVPWM technology in direct power control improves the static performance and get more sinusoidal current, and this control strategy is achieved by a power decoupling control.Thirdly, a novel real-time harmonic detection method is proposed based on instantaneous power theory, which checks out harmonic and fundamental reactive current within one period of grid. In order to achieve reactive power and harmonic compensation control, a new method that using the synchronous reference frame of harmonic to implement current control is proposed based on the discussion of the limitation of direct power control, which can eliminate the static error.At last, a TMS320F2812 DSP based experimental platform is developed to verify all the analyses of the control strategy. The experimental results demonstrate the correctness and feasibility of DPC, at the same time show the excellent performance of the strategies studied in this paper.更多还原