The Study Of Micro-grid Reactive Compensator Based On PEBB

With the successful development and operation of distributed generation and micro-grid demonstration projects, the micro-grid has become one of the trends of smart grid development. Micro-grid contains a large number of nonlinear loads of power electronic devices, which generate harmonics and reactive power. It will seriously affect the quality and stability of the micro-grid power supply. How to effectively and economically realize reactive power compensation in micro-grid has become a focus of the micro-grid research. In this paper, micro-reactive power compensation's control strategy and equipment research based on PEBBs has been discussed. The study includes the following aspects:Firstly, this paper analyzed the causes and effects of micro-grid reactive power, introduced micro-grid reactive power compensation research status and significance; for micro-grid reactive power compensation, this paper proposed reactive power compensation method based on PEBB and described the advantages of the micro-grid reactive power compensator device based on PEBB.Then, this paper introduced the topology of microgrid reactive power compensator. Through reactive power compensation device mathematical modeling, detailed analyzing of the reactive power compensation working principles was given. According to the PEBB module constructed principles, the paper completed the design of the main circuit including DC side capacitors, power switching devices, AC side filter, and other components.What is more, the paper discussed control method mainly from the DC voltage control, reactive power compensation control, and harmonic suppression control. DC voltage control based on droop control principle, sag curve develop DC voltage reference value from the value of grid voltage. The reactive power compensation device can ensure that capacity while reducing the switching loss by controlling the DC voltage reference value. Reactive power compensation contains reactive current control which based on decoupling control of the dq coordinate system, so that device can ensure efficient reactive power compensation capability in harsh operating conditions. To increase the versatility of micro reactive power compensation device, when the micro-grid distortion rate is too high, the device uses the harmonic suppression control state. Quasi PR controller in dq coordinates has been used to suppress specific harmonic, which can improve micro-grid power quality.Finally, the design of control system based on DSP and FPGA is introduced. In this paper, the control system hardware design and software development is carried out in detail, reactive power compensation and harmonic control experiments has been taken on reactive power compensation device prototype. From these experiments, the control strategy proposed in this paper is verified. In order to facilitate the industrial production, this paper studied engineering technology about thermal design, electromagnetic compatibility design and mechanical design.