Study On Power Quantity Control Technology Of Microgrid With Different Types Of Distributed Generation Connected To Grid

With the development of distributed generation and microgrid technology, the structure and electrical loads of microgrid system will become more and more complicated, and the probability of occurrence of harmonics, voltage fluctuations, flicker and other power quality problems are increasing. Microgrid connected to the power grid will seriously affect the power environment of the power grid. So, a research is carried out with the subsidization of NCFS general program(Project Number:61374132). According to the international development law of FACTS, one power quality control method which based on the active power filter (APF) and the static synchronous compensator (STATCOM) is proposed. The main contents and research findings are as follows:1. This paper research on grid-connected problem of the common distributed sources in microgrid, analyze the principle and feature of wind power generation, solar electrical energy generation and fuel cell power generation, and build the distributed sources mathematical model to study the impact of its power quality in grid-connected model.2. Analyzing rapid detection of microgrid-harmonic based on instantaneous reactive power theory, and aiming at the current delay problem in harmonic detection algorithm, this paper studied a lead-correction method, and verified its correctness and feasibility by simulation.3. Further study on the reactive power compensation principle of microgrid, and then deduced the mathematical model of reactive current detection algorithm.4. Considering tracking control of harmonic suppression and reactive power compensation’s command signal, comparative analysis of three common modulation strategies: fixed frequency hysteresis current control, three-phase SPWM modulation and SVPWM modulation, and regarding the control characteristics of APF and STATCOM, we proposed a modulation strategy which combining hysteresis current and space vector, this method not only simplified the microgrid power quality optimization equipment design difficulty, but also effectively improved the microgrid power quality.5. Through PSCAD simulation and prototype testing, the simulation and experimental results certificated the authenticity and feasibility of the microgrid power quality control theory.