Bifurcation and chaos in high-frequency peak current mode Buck converter working in continuous conduction mode（CCM） are studied in this paper. First of all, the two-dimensional discrete mapping model is established....Bifurcation and chaos in high-frequency peak current mode Buck converter working in continuous conduction mode（CCM） are studied in this paper. First of all, the two-dimensional discrete mapping model is established. Next, reference current at the period-doubling point and the border of inductor current are derived. Then, the bifurcation diagrams are drawn with the aid of MATLAB. Meanwhile, circuit simulations are executed with PSIM, and time domain waveforms as well as phase portraits in i_L–v_C plane are plotted with MATLAB on the basis of simulation data. After that, we construct the Jacobian matrix and analyze the stability of the system based on the roots of characteristic equations. Finally, the validity of theoretical analysis has been verified by circuit testing. The simulation and experimental results show that,with the increase of reference current I_（ref）, the corresponding switching frequency f is approaching to low-frequency stage continuously when the period-doubling bifurcation happens, leading to the converter tending to be unstable. With the increase of f, the corresponding Irefdecreases when the period-doubling bifurcation occurs, indicating the stable working range of the system becomes smaller.展开更多
A multicellular DCX （dc-dc transformer） using unregulated cell converters has been proposed for the environmentally friendly data centers. The high speed cell converter with the switching frequency over MHz behaves ...A multicellular DCX （dc-dc transformer） using unregulated cell converters has been proposed for the environmentally friendly data centers. The high speed cell converter with the switching frequency over MHz behaves as an ideal transformer, and this behavior solves the voltage imbalance issue in the multicellular converter topology. The analysis of the unregulated cell converter is conducted by using the state space averaging method, and the operation condition for the ideal transformer is specified. The behavior of the multicellular DCX using the high speed cell converters has been also analyzed, and the voltage imbalance issue among cell converters is discussed quantitatively. A prototype of a 19.2 kW 384 V-384 V multicellular DCX using sixty-four unregulated cell converters is fabricated and the validity of the analyses is verified.展开更多
A 10 MHz ripple-based on-time controlled buck converter is presented. A novel low-cost dual ripple compensation, which consists of coupling capacitor compensation and passive equivalent series resistance compensation,...A 10 MHz ripple-based on-time controlled buck converter is presented. A novel low-cost dual ripple compensation, which consists of coupling capacitor compensation and passive equivalent series resistance compensation, is proposed to achieve a fast load transient response and robust stability simultaneously. Implemented in a 2P4M 0.35 um CMOS process, the converter achieves fix-frequency output with a ripple of below 10 mV and an overshoot of 10 mV at 400 mA step load transient response. With width optimization of the power transistors in an ultra-heavy load and PFM control in a light load, the efficiency stays at over 83% for a load range from 20 mA to 1.5 A and the peak efficiency reaches 90.16%.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61376029)the Fundamental Research Funds for the Central Universities,Chinathe College Graduate Research and Innovation Program of Jiangsu Province,China(Grant No.SJLX15 0092)
文摘Bifurcation and chaos in high-frequency peak current mode Buck converter working in continuous conduction mode（CCM） are studied in this paper. First of all, the two-dimensional discrete mapping model is established. Next, reference current at the period-doubling point and the border of inductor current are derived. Then, the bifurcation diagrams are drawn with the aid of MATLAB. Meanwhile, circuit simulations are executed with PSIM, and time domain waveforms as well as phase portraits in i_L–v_C plane are plotted with MATLAB on the basis of simulation data. After that, we construct the Jacobian matrix and analyze the stability of the system based on the roots of characteristic equations. Finally, the validity of theoretical analysis has been verified by circuit testing. The simulation and experimental results show that,with the increase of reference current I_（ref）, the corresponding switching frequency f is approaching to low-frequency stage continuously when the period-doubling bifurcation happens, leading to the converter tending to be unstable. With the increase of f, the corresponding Irefdecreases when the period-doubling bifurcation occurs, indicating the stable working range of the system becomes smaller.
文摘A multicellular DCX （dc-dc transformer） using unregulated cell converters has been proposed for the environmentally friendly data centers. The high speed cell converter with the switching frequency over MHz behaves as an ideal transformer, and this behavior solves the voltage imbalance issue in the multicellular converter topology. The analysis of the unregulated cell converter is conducted by using the state space averaging method, and the operation condition for the ideal transformer is specified. The behavior of the multicellular DCX using the high speed cell converters has been also analyzed, and the voltage imbalance issue among cell converters is discussed quantitatively. A prototype of a 19.2 kW 384 V-384 V multicellular DCX using sixty-four unregulated cell converters is fabricated and the validity of the analyses is verified.
文摘A 10 MHz ripple-based on-time controlled buck converter is presented. A novel low-cost dual ripple compensation, which consists of coupling capacitor compensation and passive equivalent series resistance compensation, is proposed to achieve a fast load transient response and robust stability simultaneously. Implemented in a 2P4M 0.35 um CMOS process, the converter achieves fix-frequency output with a ripple of below 10 mV and an overshoot of 10 mV at 400 mA step load transient response. With width optimization of the power transistors in an ultra-heavy load and PFM control in a light load, the efficiency stays at over 83% for a load range from 20 mA to 1.5 A and the peak efficiency reaches 90.16%.
