Investigations on Multiple Energy Storage Element Resonant Power Converter

Abstract

newlineABSTRACT newlineIn recent years the design and development of various DC-DC Resonant Converters (RC) have been focused for telecommunication and aerospace applications. It is because these converters exhibits high switching losses, reduced reliability, electromagnetic interference (EMI) and acoustic noise at high frequencies. newlineResonant converters are DC-DC switching converters that include resonant tank circuit actively participating in determining input to output power flow. Resonant converters have several desirable features like zero voltage switching, zero current switching, high frequency operation, high efficiency, small size and low electromagnetic interference. newlineThe series resonant converter (SRC) and parallel resonant converter (PRC) are basic resonant converter topologies. The merits of SRC include better load efficiency and inherent DC blocking of the isolation transformer due to the series capacitor in the resonant network. However the load regulation is poor and output voltage regulation at no load is not possible by switching frequency variations. newline On the other hand, PRC offers no load regulation but suffers from poor load efficiency and lack of DC blocking for the isolation transformer. For better regulation, the LCL SPRC has been attractive for application as a constant voltage power supply. However, the leakage and magnetizing inductance of transformer along with its winding capacitance is absorbed in the four element topology. Therefore, it is seemed to be suitable for high voltage application. newlinevi newlineHence, in this research, an approach based on four element topology of resonant converter is being attempted and presented. This approach is very effective in high power applications. newlineThe mathematical model of LCLC resonant converter has been developed and simulated using MATLAB for estimating the performance under various load conditions. The performance analysis of LCLC resonant converter is clearly projected in this work with various disturbances and load conditions. Comparison of Open Loop and PI Controller was carried out and concluded that PI based LCLC resonant converter has effective output voltage regulation and high efficiency. newline Fuzzy Gain Scheduled PI controller was utilized for improving the dynamic responses identified in the existing controllers, where sudden variation of load and dynamic response of LCLC resonant converter were verified. Comparison of performance estimation for open loop, PI controller and Fuzzy Gain Scheduled PI was conducted by using MATLAB software. newlineThe results obtained indicate that the proposed approach is an effective approach in regulating the output voltage and boosting the efficiency of LCLC resonant converter. FPGA controller was used to experimentally verify the same. It has been found from the simulated results that the closed loop controller provides better control strategies.