Energy Recovery DC Electronic Load

Load is the necessities for power testing, its development and application become more and more complicate, and traditional static load has been difficult to satisfy the test requirements. Although linear electronic loads have been widely used with the advantage of high dynamic response, it is limited by the power level and great energy consumption. Switching electronic loads can achieve energy feedback, which can suit the requirement of energy conservation and emissions reduction, and improve the level of power testing. In this thesis, based on the advantages of linear electrical load and switching electronic load, conbining them to complement each other’s disadvantages, which can improve the dynamic response of the electronic load, and realize energy feedback to improve load efficiency, and reduce the input current ripple to some degree.Power MOSFET as an electronic load have been discussed in the thesis, and the thesis analysis its working principle and design a driver circuit with high bandwidth operational amplifier to achive high dynamic response of linear load. A compensation network of linear load has been designed by analyzing the model of MOSFET and stability of operational amplifiers, which can ensure the circuit working reliability. Then use multi-channel MOSFET in parallel, and each branch has an independent driving circuit, which can further improve the dynamic response of linear electronic loads, and also broaden the input power level.The thesis analysis the working principle of Switching-Boost topology as switching electronic load, and calculate topological parameters. With the input filter of converter input current ripple can be reduced. Then the compensation circuit of input current has been designed by analyzing the small-signal of the converter to keep input current stable. Meanwhile, the converter has a wide input voltage range and can achieve energy feedback.The principle of corrdination circuit of linear electronic load and switching electronic load have been introduced in this thesis, and the current sampling circuit using current mirror. Reference given circuit of linear load has been designed. When the loads change, the linear load will be put into circuit, by controlling the current of linear load to improve the dynamic response. When the circuit reaches a steady state, the current of linear load will be presented as triangular wave to compensate input current ripple. Meanwhile, it has bus voltage sampling circuit and distribution switch driving circuit, which can ensure the electronic load operate in safe voltage range.