Research On Optimization Of High Gain DC-DC Converter Based On Photovoltaic Power Generation Operation Safety Perspective

As intensified global energy crisis and environmental pollution problems,novel sustainable energy sources have increasingly become the main energy source for industrial and agricultural production.Due to the advantages of noise-free,pollution-free emissions,and cleanliness,photovoltaic power generation has gradually become one of the most important power sources in the future.Although the key technologies for the operation of photovoltaic power generation systems are maturing,the ensuing electrical safety and efficiency issues have seriously restricted the widespread development and application.Many research contents,such as improving the efficiency of photovoltaic power generation system,suppressing and reducing the damage of voltage and current impact on equipment and system,preventing fire and other issues,have gradually become a hot topic for photovoltaic scholars at home and abroad.In this paper,the current three types of hot-spot high-gain DC-DC converters with voltage doubler units were studied in detail.Specifically,the causes of hidden safety hazards were analyzed,and various performance parameters of converter were presented based on targeted optimization design and theoretical analysis.Finally,the correctness of the design was verified by simulated and real experiment.First,this paper studied the main technology of the high-gain DC-DC converter with switching inductance unit(SIU)and analyzed that the safety hazard of this type of converter is due to the presence of current surge.In order to eliminate the current surge in the structure of the SIU,a quadratic switch inductance structure was designed.Moreover,a Zeta converter with a switch inductance unit as an example was compared and verified to prove that the structure effectively suppressed the current surge.The comparison and expansion of several switch inductance structures were presented and the working essence of the converter with switch inductance structure was summarized.Then,the main technology of the high-gain Boost converter with coupled inductors(CI)and switched capacitors(SC)was studied.The analysis shows the two safety hazards of the CI-converter and the SC-Boost converter respectively.For the CI-converter,the hazard is that the resonance of the leakage inductance and the parasitic capacitance of the switching device will produce a large voltage surge when the switching device is turned off.For the SC-Boost converters,the hazard is due to the unbalance voltage of the two capacitors in series,which will produce a large current impact.In order to eliminate two types of surges,a series of coupled inductance switched capacitor(CISC)converters were designed.This converter used leakage inductance to suppress current surges in the SC structure,which also absorbed leakage inductance energy to suppress the voltage surges effectively.This design not only solves the above problems but also improve the voltage gain of converters.In addition,the diode-capacitor branch was added to the designed converter to further improve the gain of converters.A series of extended structures of coupled-inductor switched-capacitor combined converters were presented.These structures can be applied to various high-gain and high-efficiency occasions.Third,the main technology of the interleaved parallel DC-DC converter was studied.The analysis shows that the safety hazards of this type of converter are that the converter generally contains a CISC structure,which exists voltage and current surges.In order to eliminate two types of surges,an interleaved parallel Boost converter with CISC was designed,which not only suppresses the current and voltage surge in the converter but also increases the voltage gain exponentially,retains advantages of current continuity and smaller input current ripple.This design optimizes the overall performance of the converter and reduce EMI.The above four types optimally designed converters not only effectively suppress or absorb the voltage surge and current surge in the converter,but also reduce the voltage stress on the components.These designs improve the stability,safety,efficiency and service life of the converter,prevent the occurrence of fire and solve the existing safety hazards.There are 120 diagrams,12 tables and 124 references in this paper.