Abstract
When an input terminal is connected to a solar panel with a low voltage level and large power range fluctuation, a Boost type CLLC converter controlled by fixed frequency pulse width modulation (PWM) reduces the utilization of PV electric energy, and the synchronous drive of the secondary side and primary side ensures that the converter operates with low efficiency when the duty cycle is shifted by 0.5. To maximize the utilization of photovoltaic (PV) energy in a PV power generation system and improve the conversion efficiency, this paper studies a Boost CLLC converter with high gain and soft switching controlled by PWM-pulse frequency modulation (PFM) hybrid modulation for PV power generation. By controlling the duty cycle and switching frequency of the primary MOSFETs, the converter can stabilize the output voltage while tracking the PV maximum power point. Under such a hybrid control, the resonant gain of the converter is greater than 1, the voltage gain is large, one of the MOSFETs at the primary side is in a zero-voltage-switching-open (ZVS-ON) state, two diodes are used to realize zero-current-switching (ZCS) soft switching on the secondary side, and the efficiency of the converter is high. In addition, this paper studies the phenomenon of backflow power in the resonant circuit and the influence of a change in the switching frequency on the magnitude of the backflow power. Finally, a 500W experimental prototype was constructed to verify the accuracy of the theoretical analysis and the feasibility of the control method.
Highlights
INTRODUCTIONPhotovoltaic (PV) has been the fastest-growing energy technology over the past 15 years [1]
Among renewable energy sources, photovoltaic (PV) has been the fastest-growing energy technology over the past 15 years [1]
Increasing the proportion of PV power generation in the grid power generation system is of great significance for promoting national economic development and solving the problem of pollution caused by traditional fossil fuel power generation
Summary
Photovoltaic (PV) has been the fastest-growing energy technology over the past 15 years [1]. We propose a Boost-type soft-switching, high-gain CLLC converter with PWM-pulse frequency modulation (PFM) hybrid control for PV power generation. This means that the converter can achieve a high voltage gain in a narrow switching frequency range. Given the input and output conditions, we can know that the effective value of the resonance current for the primary and secondary sides decreases with increasing excitation inductance Lm. The input of the converter is a low voltage PV, so it is necessary to ensure that the voltage gain of the resonant tank is large. Compared with the traditional Boost converter gain [3.3, 1.4], it has obvious advantages
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
