Research On Staggered Parallel Bi-directional LLC Resonant Converter

Based on the topology of the bi-directional LLC resonant converter,the main working process and the input impedance characteristics of the converter in the ideal operating frequency range are analyzed in detail.The expression of the input impedance and the voltage gain are obtained.It also provides a theoretical basis for analyzing the specific operating range of the converter and selecting the resonant component parameters.In the selection of the resonant component parameters,in order to make the operating frequency adjustment more smooth,and the converter in the full load range can achieve zero voltage,a new kind of restrictions is put forward.Then,the loss of each part of the converter is analyzed and calculated,and the correspondence between the normalized frequency of each load point and the load is introduced to improve the calculation accuracy of the loss.And interleaving technology and channel control technology are applied into the converter,so as to achieve high transmission efficiency when the converter in high-power output,and it can reduce the output current,voltage ripple.Then,the optimal commutation point required for channel control is obtained by using the total loss corresponding to the number of different working channels of the converter.Finally,the feasibility of the resonant parameters and the reliability of the selected devices are verified by saber simulation.Then the experimental results show that the converter has high transmission efficiency in the entire load range,and the correctness of the theory is further verified.