Research On DSP-Controlled System Of Power Grid Signal Processing And Power Quality Compensation

As results of the development of modern science and technology, on the one hand, factors of power quality problems caused by a large number of non-linear load become more and more; on the other hand, kinds of complex and sophisticated electrical equipment have been popular, what induces that the demand of power quality and reliability have been increasing. These issues have now been more and more striking, which makes that power quality problems may do greater harm to power grid and distribution system and cause larger losses in human life and production activity. Power quality is directly related to the overall effectiveness of the national economy. However, China’s research in related fields is still very backward at present. So it is very necessary to greatly strengthen studies on methods for improving power quality.In this paper, we start with analysis of Grid harmonics, construct a system to compensate and improve power quality, which uses high-performance DSP and IPM (Intelligent Power Module) as the core, FFT (Fast Fourier Transform) and SPWM (Sine Pulse Width Modulation) as the principle.Our system samples Grid signal via data acquisition subsystem, and send the A/D converted signals to DSP. In DSP, FFT will be done and the harmonics will be analyzed and processed to get relevant information of higher harmonics, so as to generate control signals to drive IPM module. Then APF outputs reactive power and harmonics compensation voltage signals to power grid to compensate them with the purpose of improving the power quality. Meanwhile, the system also includes fault protection subsystems to ensure the security and reliability, and the human-computer interaction interface to monitor real-time operating conditions.The first chapter introduced background to the study of power quality, the status quo and development trend. Chapter II particularly described the basic principles of signal processing and harmonic compensation, and the details of related structures. With analysis of common solutions, we bring forward ours for this system. Chapter III presented the system’s hardware structure, consists of several subsystems, and analyzed some frequent issues in hardware design. Then in Chapter IV, we designed software to achieve the functions of the system, realize DSP signal processing and controlled variable output. Chapter V recorded the experiments carried out on a prototype to verify the functions of this system. The experimental results have also been analyzed. Finally, in Chapter VI, we gave out summary of the system and an outlook of future study direction.