The output voltage of direct-driven wind generator was changing dynamically with environmental wind speed, and the variable range of wind speed was larger. In order to decline or promote DC voltage, the buck/boost converter was needed, so as to becomingly adjust DC voltage inflicted on the input of inverter, and ensure the inverter work normally. The constitution of DC/DC converter in direct-driven wind power system was expatiated, and the operation principle, control strategy of it were analyzed in detail. The wind power system was simulated in Matlab, and the testing equipment was designed and constituted. The experiment and simulation results show that, the converter can implement promoting or declining the input DC voltage, dynamically adjusting the input DC voltage of inverter, and the safety operation of inverter can be guaranteed.

Control and realization of DC/DC converter in direct driven wind power system

A new type of converter for train was designed.The input voltage of the converter is from 35 V to 90 V and the output voltage is 50 V.The rated output power of the converter is 300 W.The Buck-Boost topology was adopted in the main circuit,and the two parallel MOSFETs were driven respectively by means of complementary control.The SG3525 which can give out two complementary PWM signal was used as controller.The small-signal model of the buck-boost converter in Continuous Conduction Mode(CCM) was built by state-space average method,and the control-to-output transfer function of the power link was deduced.The bode diagrams of the open-loop transfer function were drawn using in Matlab,and the double poles-double zeros compensating network was designed and the parameters were calculated through analyzing characteristics of bode diagrams.The simulation model of the converter was established by Matlab/Simulink and the simulation result was given.Within the range of the changes of the input voltage,a series of experiments in light load and heavy load were made.The Simulation and experimental results are presented to verify the validity of and correctness of the method and the theory.

Zhang Ning

Papers

Research of Buck-Boost Converter for Trains