Switched Capacitor Zeta Converter Based On Coupled Inductor

Due to the constant decline of non-renewable energy like coal,the development of various renewable energy sources has attracted increasing attention.As a major model of development for renewable energy,solar energy produces no pollution and is widely available.However,due to the low output voltage of photovoltaic module,it is a must to connect the DC converter with high boost ratio for improving the output voltage to the level as required for load or grid-connected voltage.Therefore,it is essential to develop new high gain and high efficiency DC-DC converter.This study starts by proposing a Zeta converter(CI-Zeta)on the basis of coupled inductor voltage doubling unit.An analysis is conducted of how the proposed converter functions in CCM mode,DCM mode and boundary conditions of the BCM mode.Meanwhile,in order to inhibit the voltage peak resulting from the parasitic capacitance and leakage resonance of the switch tube and while making the switch tube less stressed,the diode-capacitor branch is taken as the clamp absorption branch.According to the simulation results,not only is the converter capable to reach a high boost ratio of 8.3 times,it is also effective in reducing the voltage stress of the switch tube by roughly half relative to the conventional Zeta converter.Subsequently,the CI-Zeta converter is added with switching capacitor,i.e.,the double voltage clamp circuit.Based on coupling inductance,the switching capacitor Zeta converter is further proposed(CISC-Zeta).When the switch tube is not functioning,the two voltage doubling clamp capacitors are left in the state of parallel charging In this case,not only can the leakage energy be absorbed,the current stress of the corresponding diode is also lowered as a result of parallel shunt.Consequently,voltage gain improves.An analysis is conducted of how CISC-Zeta converter works in CCM and DCM mode.Then,the transition and critical conditions between the two modes are determined through calculation.A comparison is performed between the converter and other improved Zeta converters in performance.Finally,simulation is performed to verify it.It is found out that the boost ratio of the converter improves to 10 times,while there is a decline in the voltage and current stress of the power device.Afterwards,for modeling the small signal of the switched capacitor Zeta converter according to the coupling inductance,the state space method is applied.Further with this,a design of the closed-loop compensation network is worked out for the converter.In order to validate the theoretical analysis,a principle prototype is constructed with TMS320F28335 as the core control device.The paper uses 57 pictures,6tables,and 54 references.