Research on control strategies for small-scale wind-solar hybrid generation systems by modelling and simulation

Abstract

In the districts where solar energy and wind energy are naturally complementary, the application of wind-solar hybrid generation systems (WSHGS) can reduce the storage capacity of batteries and the total cost of the system compared with stand-alone PV or wind generation system. But the efficient and reliable operation of WSHGS depends on the control strategies of the controller. There are still some drawbacks as follows in current 1KW-3KW products of WSHGS: 1) the charging voltage of batteries is controlled by using voltage hysteresis comparison. 2) Solar array and wind turbine can not operate at maximum power point. To improve the performances of controller used in WSHGS at present, the following control strategies are presented in this paper: 1) PWM chopping charging control technology; 2) Constant voltage and limited current double close-loop control of the converter. The simulation results show that batteries can be charged in float charging mode, which may enhance the cycle rate and prolong the life of the batteries. Besides, Both wind and solar generation system can operate about at maximum power point respectively with more reliability, higher efficiency and lower cost. Copyright © (2007) by the International Solar Energy Society.