Fast photovoltaic simulator based on D/A mixed control

GU Ye，DENG Yan，LI Guang-di，WANG Kun

（College of Electrical Engineering，Zhejiang University，Hangzhou 310027，China）

Abstract：Aiming at the increasing perturbation frequency in maximum power point tracking（MPPT）algorithms，a photovoltaic simulator is designed with digital/analog mixed control. The digital part of the simulator was realized by a digital signal processor（DSP），which adopts the four- segment piecewise linear fitting method to build the photovoltaic characteristic curve and uses the load impedance location method to find the accurate steady-state operation point within only one calculation cycle. In the analog part，the power converter was realized by using a peak current controlled synchronous BUCK，whose output voltage and current follows the photovoltaic reference

value produced by the digital part. The model of the simulator was built to analyze its response time，which is about 0.22 ms and meets the requirements of the photovoltaic inverters' MPPT algorithms. The results of simulation and emperiments indicate that the theoretical analyses are accurate and the proposed simulator is feasible.