Research On Measurement Technology Of Bidirectional Electric Energy In Distributed Power Supply

This thesis mainly introduces the research and development of the Measurement Technology of Bidirectional Electric Energy in Distributed Power Supply. The implementations of the software and hardware applying this technology are expounded in detail and some improvements are proposed according to the experiments data.The system is composed of Input Circuit, Measurement Unit. PMU and Display Unit. Input Circuit adopts voltage and current transducers to get electrical signals and after signal conditioning they are sent to Measurement Unit. Measurement Unit includes ADC and DSP measurement core. Analog signals are dispersed into digital signals which are counted by DSP to calculate the electrical parameters and A/C sampling is used in order to calculate accurately. And the PMU can provide reliable and stable sources for the devices in circuit. Display Unit carries out display of voltage RMS, current RMS, power factor, active power of forward/backward direction and electric energy. The realization of this system proves the correctness and feasibility of the Measurement Technology of Bidirectional Electric Energy and provides the theory groundwork and hardware basis for the application in grid-connected PV systems.The thesis analyzes the errors and makes the improvements in software aspectsuch as how to improve data precision and adopting digital filtering method as well asin hardware aspect where synchronized sampling and selection of ADC are provided.