Research on current feed forward decoupling control for energy feedback and grid-connected device

Abstract

Considering the disadvantages of traditional control strategy which is used on the motor energy feedback and grid-connected device parallel connecting on the DC side of AC-DC-AC frequency convertor, such as slow dynamic response and poor grid-connected power quality, a double closed-loop current feed forward decoupling control strategy with grid voltage sensor-less has been adopted. The method estimates grid voltage on the basis of the DC side voltage and switching function, and makes it as a feed forward compensation to realize direct current decoupling control. Modulated by SVPWM, the motor regenerative braking energy could feedback to the grid with higher power factor, good robustness, small harmonic pollution and fast dynamic response. Meanwhile, the DC side voltage maintains constant in feedback process. Therefore, the method can reduce the cost of energy feedback device and achieve the purpose of energy conservation. MATLAB simulation and experimental results are presented to verify the analysis and control proposed.