基于特定次谐波检测的并联型有源电力滤波器电流优化-电气工程专业论文.docx

上海交通大学工程硕士专业学位论文 上海交通大学工程硕士专业学位论文 ABSTRACT 第 PAGE 第 PAGE VII 页 万方数据 CURRENT OPTIMIZATION OF SHUNT ACTIVE POWER FILTER BASED ON FIXED HARMONICS DETECTION ABSTRACT The development and application of power electronics accelerate effectively the process of modern industrialization, while bringing out serious harmonic pollution to power systems. As a power electronic device, shunt active power filters (SAPF) have obvious advantages and will be the main products to improve the power quality in the future. This paper firstly introduces the reason, damage, international standard and governance method of harmonics. After the relative merits of passive filters and active filters are discussed, it summarizes the history and current station of active filter about topology structure and control strategy. Traditional active filters always adopt the mode of all harmonics, that all harmonics is calculated and tracked through detecting the fundamental part of grid current. In special grid environment, this mode may lead the device over-current and even damage the switching elements when compensative harmonics exceed the nominal capacity of device. Therefore, this paper proposes the linear limiting algorithm, which is designed to guarantee the device safety and steady by limiting the RMS and peak values of reference current. Given the necessity of fixed harmonics detection, some algorithm based on Fourier analysis, dq0 transformation and adaptive theory are discussed on workload, real-time and computational accuracy. Besides, this paper also supposes the design means of three-phase PLL and single-phase PLL. PI controller is generally used in industry for its simple principle. But the wide frequency spectrum of reference current makes this controller have a large deviation in active filter. So, fuzzy PI adaptive controller is proposed to eliminate this error through adjusting the PI parameters online. The dead-time effect of switching elements will inevitably generate voltage harmo