Study On DC Boost Converter And Its Control Strategy For Photovoltaic System

The disadvantages caused by this fossil energy supply have become increasingly prominent.Photovoltaic power generation system has been paid attention to and researched by a large number of experts and scholars in the field of new energy because of its clean,renewable and non-polluting characteristics,and its working conditions are not limited by the geographical location of mountains and rivers.Photovoltaic system is a system that integrates photovoltaic power generation,power transformation,and power generation,which uses solar energy as the initial energy source,and is generally divided into a single-stage system and a multi-stage system.As the single-stage system requires more functions of its inverter unit,resulting in its complex control circuit and its high requirements on the controller’s hard conditions,it is difficult to ensure the system’s continuous and stable operation.Therefore,at present,the commonly used photovoltaic power generation system is a multi-stage system,and the multi-level system is mainly based on a two-stage system.The pre-stage DC boost converter in a two-stage photovoltaic power generation system and its control method assume the purpose of DC boosting and its maximum power point tracking(MPPT),which determines its use in photovoltaic power generation systems.A decisive position,and thus a significant practical significance for its research.1.The working principle of Photovoltaic cell(PV)is described,and its simulation module is built on the Simulink platform in combination with its mathematical model.Finally,the output characteristics of the PV are simulated by simulating changing light intensity and ambient temperature.The simulation results show that the maximum output power of the PV increases with the increase of the light intensity in the process of constant ambient temperature and gradual increase of the light intensity,and at the same time the output of the PV at the maximum power point under different light intensities The voltage value is almost constant;the maximum power output of the PV decreases with the increase of the ambient temperature during the change of the light intensity and the ambient temperature gradually increases,and at the same time,the PV is at the maximum power point at different ambient temperatures.The output current value is almost unchanged.2.The topology structures of two new high-gain DC boost converters are proposed,and the detailed theoretical analysis and formula derivation of their operating principles and performance characteristics are conducted.Finally,some common high-gain converters are compared and studied.The comparison results show that the two new high-gain converters have a simple topology and a simple control strategy.The voltage gain is higher at the lower duty cycle,and the voltage stress of the switch and the diode is lower at the same output voltage and the inductor current.The value is smaller and other advantages.3.A novel partition-adaptive variable-step-length MPPT algorithm is proposed for the control of high-gain DC boost converters in photovoltaic systems.The working principle and implementation of the new algorithm are introduced in detail.Finally,the new algorithm and disturbance observation method are simulated and compared with the above new high-gain DC boost converter.The experimental results show that the new algorithm has the advantages of simple realization and strong step-size adaptation.The steady-state performance of the PU curve is small when the steady-state oscillation is small,and it can be quickly traced when the ambient temperature and light intensity change greatly.MPP is the dynamic response and other advantages.4.Combining the topologies of the two new high-gain DC boost converters mentioned above,an experimental prototype with a rated power of 200 W was built in the laboratory.When the test parameters are determined,the input/output voltage waveforms,switching tube drive signal waveforms,switch tube and diode voltage stress waveforms in the test sample are collected,and the energy conversion efficiency is analyzed as the output voltage changes.The consistency of the experimental waveforms and the theoretical analysis values of the experimental prototype was confirmed,thus demonstrating the effectiveness of the two new high-gain DC boost converters.