The Design Of The Photovoltaic Power Generation DC Energy Meter Based On MKM34Z128

Nowadays,the DC power is widely used in photovoltaic power generation,electric vehicles,high voltage transmission,rail transportation,large industrial and substation,among them,photovoltaic power generation,electric vehicles and high voltage DC transmission as an emerging industry which won the the strong support of the country.The State Administration of quality supervision,inspection and quarantine and National Grid Corporation as well as China Southern Power Grid Company introduced the relevant standards of the photovoltaic power generation and its ancillary equipment gradually,mean while,the State Council and other relevant departments also issued a series of supportive policies for photovoltaic power generation.As the electricity of photovoltaic energy was often consist of the DC power,the photovoltaic power generation transmission and electric process always included DC electric energy metering,then,this thesis designed a DC electric energy meter which was used to solve the photovoltaic DC electric energy metering and billing management.Firstly,this thesis introduces the background and significance of the research,then analyzes the research status and development trend of the DC electric energy meter,and expounds the main content and structure of this thesis.Then this thesis introduces the working principle and the key technology of the DC electric energy meter and the software as well as hardware design scheme,and which is discussed specially.As to the hardware part,a detailed analysis of the power supply circuit,DC current and voltage sampling circuit,RS485 communication circuit respectively,and of power supply and communication circuits were electrical isolation design,sampling circuit RC filter processing,which can effectively ensure the hardware system stability;meanwhile,as the part of software,it mainly uses the way of modular design,which make the layer of application and bottom drive independent,andwhich make the structure of the program clear,code facilitately transplanting and function cutting,then it analyzes the electric energy metering and communications applications as well as communications applications which support MODBUS and DL/T-645-2007 dual protocol detailly.At last,we test the function and performance of DC electric energy meter and the result of this test is given.As to the function,using the method of white box to test DC electric energy meter of all the features and the full coverage testing;and for the content of performance testing which relates to electromagnetic compatibility,electrical properties and insulation properties and mechanical properties,and so on several aspects of the test,followed by a DC electric energy meter accuracy test and error analysis,results show that in this thesis,the design of DC electric energy meter accuracy class for class 1,which meet the functional specification of the national grid of DC electric energy meter,and which can meet the needs of the development of photovoltaic power generation equipment market.