| The spacecrafts like satellites and space stations all require electric propulsion sys-tems to complete attitude control or position correction tasks through electrical energy conversion.The propulsion system generally occupies 10%～50% of the weight of the spacecraft.Due to the limitation of the carrying capacity,the harsh working environment and other factors,the space power supply put forward more demanding requirements in electrical energy conversion,miniaturization and light weight.The emergence of the new semiconductor material gallium nitride(Ga N)has promoted the increase of switching fre-quency of power supplies,however,the increase of frequency has also produced many serious effects on magnetic components.The parasitic parameters and loss effects of pla-nar magnetic elements in high ratio power supplies under high frequency operation are addressed.The main research work of this paper is as follows.(1)A detailed analysis of the operating modes of the LCLC-based full-bridge DC/DC power supply is carried out,and the conditions required for soft switching of the power supply are derived from the analysis results? the voltage gain and transfer function of the LCLC resonant circuit are analyzed by the first fundamental approximation method,and the resonant inductance and frequency parameters are derived for the LCLC resonant circuit in different.The resonant inductance and frequency parameters of LCLC resonant converter are analyzed for different operating regions.(2)The parasitic parameters of the magnetic element such as leakage inductance and distributed capacitance are modeled in detail,and it is concluded that the winding structure of the magnetic element has an important influence on the parasitic parameters of the transformer through the modeling analysis and Maxwell 3D finite element simulation.(3)The loss model of single winding magnetic element is analyzed at first,the rela-tionship between winding thickness and frequency of the loss is derived by further model-ing of multi-layer winding loss then.The results of finite element simulation with Maxwell3 D show that the number of winding layers and winding structure all have great influence on the loss of winding loss.Based on the analysis above,a method of optimizing the magnetic element is derived at last.The simulation and experimental results show that the analysis of the LCLC resonant converter,the modeling of the parasitic parameters and loss of the magnetic components are reasonable and reliable.Finally,the design and application of the magnetic com-ponents are verified in a 24V/1.8k V,24 W full-bridge DC/DC LCLC resonant converter prototype.The results show that the overall converter efficiency reaches 80% for the op-erating frequency of 100-300k Hz,where the voltage gain is maximized at the operating frequency of 250 k Hz and the output efficiency reaches 97.91 %.Compared with the tradi-tional magnetic element,the power density of the magnetic element is increased by more than 30%,and the obtained research conclusions about the planar magnetic element have good reference significance for the design of DC/DC resonant converter. |
