| With the increasing frequency of space exploration,space technology is developing rapidly.Power system is one of the key subsystems of spacecraft,and its power generation mode usually adopts solar array power generation.But the output characteristics of solar cells are easily influenced by the external environment,and at the same time,they are highly nonlinear.Therefore,how to improve the energy utilization of solar array and maximize the use of solar energy is one of the most important issues in space technology.Maximum power point tracking(MPPT)technology can improve the efficiency of solar array energy transmission,and meet the requirements of different types of spacecraft for increasing power and decreasing the area of solar panels.It is one of the important development directions of space power technology.Based on the application of MPPT technology at home and abroad,a new MPPT control circuit is proposed.Traditional voltage control method is improved in this paper.The voltage and current perturbation algorithm is implemented by hardware circuit,and the control circuit and algorithm studied are simulated and verified by experiments.The specific contents include the following four aspects:Based on analysis of traditional DC/DC circuit,a new type of Buck-boost circuit is proposed through circuit transformation.This paper analyzes three kinds of working modes of new Buck-boost circuit: boost,DET and buck.According to different working modes,parameters of inductance and capacitance in the circuit are designed.Through state space averaging method,a static mathematical model of new Buck-boost circuit mode is established,and the small signal alternating current model is linearized,and simulation analysis is carried out.The closed-loop stability and dynamic characteristics of the new topology are deeply studied.Aimed at slow dynamic response speed of traditional voltage control and current control method,poor ability of anti input disturbance,and steady state error of single cycle control method,hybrid control method of single period and PI is applied to the circuit of DC/DC converter,which realizes closed-loop design with feedforward voltage control.Control performance of voltage control,single cycle control and new control method are compared by simulation.In the research of MPPT algorithm,research of MPPT algorithms at home and abroad is analyzed and compared,and advantages and disadvantages of different algorithms are pointed out.Based on high requirement for MPPT algorithm circuit in space power supply controller,an algorithm is put forward which contains no multiplication and division,and is easy to achieve.The analog circuit of the new MPPT algorithm is designed and its working principle is analyzed.Simulation of new MPPT algorithm is carried out to verify the tracking effect of maximum power point of solar array.Experimental verification of new MPPT power control system is carried out,the results show that based on single cycle and PI hybrid control technology,adopting new Buck-boost circuit,voltage and current perturbation algorithm can improve energy transmission efficiency of the solar array effectively,improve control performance of power supply system,realize design of new MPPT algorithm. |
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