| As clean energy sources,photovoltaic cells and fuel cells have developed rapidly in recent years.For the core components of photovoltaic circuit boards and fuel cells,due to their low output voltage(18-56V),they cannot be directly connected to the grid or supply DC loads.Therefore,a DC-DC converter is required to increase the output voltage to adapt to applications in different occasions.Because of the high requirements for the boost and control stability of this level of DCDC converters,the industry is actively researching high-gain,high-efficiency DC-DC converters.The use of coupled inductors to double the voltage of the DC-DC converter has always been a research hotspot in the industry.How to reduce the loss of the converter while increasing the voltage gain of the DC-DC converter,reduce the volume of the converter,and improve the converter The power density is the goal pursued by researchers.Based on the analysis of the coupled inductance voltage doubler unit,this research analyzes its port characteristics during circuit mode conversion,uses diode and capacitor clamps to solve its port voltage spikes,and proposes a coupled inductor and single-stage CD voltage doubler Boost converter.The converter uses two coupled inductance voltage doubling units to form the primary side into an active switch inductor double Boost structure,which realizes that the coupled inductor can complete its own voltage doubling,and also realize the parallel charging and series discharging of two coupled inductance units,further improving Voltage gain,while using the diode-capacitor branch as a clamp absorption loop combined with a coupled inductor to recover the leakage inductance energy.In order to meet the needs of higher voltage gain in some special applications,this research expands the single-stage CD on the basis of the coupled inductor and single-stage CD voltage doubler,and proposes a boost converter with coupled inductor and double-stage CD voltage doubler..The transformer leakage inductance equivalent circuit is used to model the coupled inductance,the working principles of the two converters are analyzed,and the volt-second product analysis method is used to calculate the voltage gain and the voltage stress of the power device.For the Boost converter with coupled inductor and single-stage CD voltage doubler,its voltage gain is(1+D+2nk)times that of the traditional Boost converter;for the Boost converter with coupled inductor and double-stage CD voltage doubler,its voltage gain is(2n+1)(1+D)times of the traditional Boost converter;the voltage gain of the converter increases with the increase of the coupling inductor turns ratio and the degree of coupling.Using a graphical comparison method,the steady-state performance of the two converters is compared with the same type of coupledinductance voltage doubler converter.The results show that the two topologies have higher voltage gain and lower switch tube voltage stress.For the Boost converter of coupled inductor and singlestage CD doubler voltage,the coupled inductor is designed,and the design schemes of "EI" magnetic core,"EE" magnetic core and "pot type" magnetic core are given,and the comparison is carried out.Analysis shows that the EI core structure has the advantage of small space and volume,while the leakage inductance of the pot core is small.In order to verify the correctness of the theoretical analysis,the PSIM power electronics simulation software was used for simulation.Based on the simulation verification,the PCB circuit board was designed and the experimental prototype was built.The prototype test and simulation results also verified the correctness of the theoretical analysis.The converter has good output steady-state electrical performance.The paper has 68 figures,6 tables,and 53 references. |
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