A Low-Complexity Trajectory Controller for Reduced Conduction Losses in Series-Resonant Dual Half-Bridge Converters
A Low-Complexity Trajectory Controller for Reduced Conduction Losses in Series-Resonant Dual Half-Bridge Converters
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DOI：
10.1109/tpel.2018.2796141
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发表时间：
2018-01
影响因子：
6.7
通讯作者：
Francesco Bez;Weijian Han;L. Corradini
中科院分区：
文献类型：
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作者：
Francesco Bez;Weijian Han;L. Corradini
本文描述了一种低复杂度的轨迹控制器，用于实现串联谐振双半桥变换器（SR-DHB）导通损耗的近最优最小化。该技术建立在谐振变换器最小电流轨迹（MCT）概念的基础上，并为SR-DHB拓扑结构制定了MCT的分段线性近似（PWL-MCT），可以通过标准算术运算实现数字化。这种技术的低复杂度实现使其适合于在商业微控制器中轻松实现，甚至在定制设计的数字IC中实现，具体取决于目标应用需求。更重要的是，基于mct的控制轨迹可以独立于变流器参数制定，从而形成最广泛适用性的控制方法。当配备这种简单的轨迹控制器时，SR-DHB转换器成为一种高效、可控的双向dc - dc电源单元，可用于多种场景，包括直流配电系统和电池对电池的电源接口。与传统的移相调制相比，所提出的轨迹控制器在中轻负载水平下具有更高的效率，在重载水平下具有相同的效率。此外，所提出的PWL-MCT概念可以实现，以适应转换器电压转换比的广泛变化，使所得到的功率单元通用和电压可编程。该方法在800w， 200v至145v， SR-DHB转换器样机上得到了验证。讨论了效率比较，强调了PWL-MCT控制器与传统调制方法相比的优势，以及在电压转换比远离标称电压转换比时实现的强大效率提高。
This paper describes a low-complexity trajectory controller for near-optimal minimization of conduction losses in series-resonant, dual half-bridge converters (SR-DHB). The technique builds on the concept of minimum current trajectory (MCT) of a resonant converter, and formulates a piecewise-linear approximation of the MCT (PWL-MCT) for an SR-DHB topology, which can be implemented digitally via standard arithmetic operations. The low-complexity realization of such technique makes it suitable to be easily implemented in a commercial microcontroller, or even inside a custom-designed digital IC, depending on the target application requirements. Even more importantly, the MCT-based control trajectory can be formulated independently of the converter parameters, resulting in a control approach of the broadest applicability. When equipped with such simple trajectory controller, the SR-DHB converter becomes an efficient, controllable bidirectional dc–dc power unit, which can be employed in a number of scenarios, including dc power distribution systems and battery-to-battery power interfaces. Compared with traditional phase shift modulation, the proposed trajectory controller yields higher efficiency at intermediate-to-light load levels, and equal efficiency at heavy load. Furthermore, the proposed PWL-MCT concept can be implemented to accommodate wide variations in the converter voltage conversion ratio, making the resulting power unit versatile and voltage-programmable. The proposed approach is validated on a 800 W, 200 V-to-145 V, SR-DHB converter prototype. Efficiency comparisons are discussed highlighting the benefits of the PWL-MCT controller over traditional modulation approaches, and the strong efficiency improvement achievable at voltage conversion ratios away from the nominal one.