This paper analyzes the optimal switching modes of the dual-active-bridge(DAB)DC-DC converter to minimize losses in DC-DC converters that exhibit a wide voltage range,high efficiency,and high performance.By solving th...This paper analyzes the optimal switching modes of the dual-active-bridge(DAB)DC-DC converter to minimize losses in DC-DC converters that exhibit a wide voltage range,high efficiency,and high performance.By solving the multiobjective constrained conditional extremums with the Karush-KuhnTucker(KKT)method,a triple-phase-shift(TPS)optimal modulation with full range of operation,global continuity,and simple calculation is obtained.By adopting TPS modulation,the DAB can decrease reactive power when dc voltages are mismatched and obtain global optimization of conduction loss and soft-switching in the full range of operation.Generation of dc-offset current in the ac link is analyzed.Static and dynamic dc-offset currents are suppressed based on TPS modulation.With direct-power feed-forward,high-dynamic control is used to improve system response to external disturbances.The digital control strategy of the whole system is designed,and optimal modulation and high-performance control are verified on the experimental prototype.展开更多
In this paper, a non-isolated stacked bidirectional DC-DC converter with zero-voltage-switching(ZVS) is introduced for the high step-up/step-down conversion systems. The extremely narrow turn-on and/or turn-off duty c...In this paper, a non-isolated stacked bidirectional DC-DC converter with zero-voltage-switching(ZVS) is introduced for the high step-up/step-down conversion systems. The extremely narrow turn-on and/or turn-off duty cycle existing in the conventional bidirectional buck-boost converters can be extended due to the stacked module configuration for large voltage conversion ratio applications. Furthermore, the switch voltage stress is halved because of the series connection of half bridge modules. The PWM plus phase-shift control strategy is employed, where the duty cycle is adopted to regulate the voltages between the input and output sides and the phaseshift angle is applied to achieve the power flow regulation.This decoupled control scheme can not only realize seamless bidirectional transition operation, but also achieve adaptive voltage balance for the power switches. In addition, ZVS soft-switching operation for all active switches is realized to minimize the switching losses. Finally, a prototype of 1 kW operating at 100 kHz is built and tested to demonstrate the effectiveness of the proposed converter and the control strategy.展开更多
This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems...This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.展开更多
基金supported by the National Natural Science Foundation of China(51807200)。
文摘This paper analyzes the optimal switching modes of the dual-active-bridge(DAB)DC-DC converter to minimize losses in DC-DC converters that exhibit a wide voltage range,high efficiency,and high performance.By solving the multiobjective constrained conditional extremums with the Karush-KuhnTucker(KKT)method,a triple-phase-shift(TPS)optimal modulation with full range of operation,global continuity,and simple calculation is obtained.By adopting TPS modulation,the DAB can decrease reactive power when dc voltages are mismatched and obtain global optimization of conduction loss and soft-switching in the full range of operation.Generation of dc-offset current in the ac link is analyzed.Static and dynamic dc-offset currents are suppressed based on TPS modulation.With direct-power feed-forward,high-dynamic control is used to improve system response to external disturbances.The digital control strategy of the whole system is designed,and optimal modulation and high-performance control are verified on the experimental prototype.
基金supported by National Natural Science Foundation of China(No.51277195)
文摘In this paper, a non-isolated stacked bidirectional DC-DC converter with zero-voltage-switching(ZVS) is introduced for the high step-up/step-down conversion systems. The extremely narrow turn-on and/or turn-off duty cycle existing in the conventional bidirectional buck-boost converters can be extended due to the stacked module configuration for large voltage conversion ratio applications. Furthermore, the switch voltage stress is halved because of the series connection of half bridge modules. The PWM plus phase-shift control strategy is employed, where the duty cycle is adopted to regulate the voltages between the input and output sides and the phaseshift angle is applied to achieve the power flow regulation.This decoupled control scheme can not only realize seamless bidirectional transition operation, but also achieve adaptive voltage balance for the power switches. In addition, ZVS soft-switching operation for all active switches is realized to minimize the switching losses. Finally, a prototype of 1 kW operating at 100 kHz is built and tested to demonstrate the effectiveness of the proposed converter and the control strategy.
文摘This article gives an overview of the main passive solutions and active techniques, based on AC switches to limit inrush currents in medium power AC-DC converters （up to 3.7 kW） for electric vehicle charging systems. In particular, a strategy, based on SCR （silicon controlled rectifier） phase, shift control in a mixed rectifier bridge with diodes and thyristors, is proposed. The challenge is to help designers optimize the triggering delay of SCRs to both limit the peak value of inrush current spikes and optimize the charge duration of the DC-link capacitor. A mathematical model （Mathcad engineering tool） has been defined to point out, the interest of a variable triggering delay to control SCRs to meet the expectations described previously. Experimental measurements using an industrial evaluation board of the AC-DC converter demonstrate the robustness of the method.
