Gallium nitride (GaN) high-electron-mobility transistor (HEMT) has the advantages of high switching speed and low ON-resistance, which make it widely used in high-frequency applications to realize high power density. Triangular current mode (TCM) modulation has been used in GaN-based converters to simultaneously achieve high power density and high efficiency through full-range zero voltage switching (ZVS). However, as switching frequency increases, the effect of dead time becomes more significant. Meanwhile, because of the junction capacitors of GaN HEMTs, the optimum dead time changes greatly with the turn-off current. Inappropriate dead time will induce extra loss that goes against the further improvement of power density. In order to minimize the dead-time loss in GaN HEMT-based TCM converter, this article proposes a strategy of adaptive deadtime control. An accurate turn-off transient model is proposed to calculate optimal dead time with consideration of the nonlinear capacitors. Based on this model, a loss model is established to evaluate the effect of dead time involving the short circuit in dead time. A new method of drive signal generation in TCM is proposed to increase the accuracy of dead-time control and reduce the current ripple. By reusing the detection signal in TCM, the adaptive dead-time control is realized without extra sensors. The proposed model is verified by a dual-pulse test, which shows the maximum error between the calculated and the experimental turn-off time is below 3 ns. The proposed adaptive dead-time control is implemented in a GaN HEMT-based boost converter. The experimental results show that the adaptive dead-time control can improve the efficiency over all operation conditions compared with using the fixed dead time, and the total loss is reduced by 26.7% at 800-W load and 70.8% at 50-W load.

中文翻译：

---

基于三角形电流模式操作中考虑非线性结电容的GaN HEMT的基于模型的高效自适应死区控制方法

氮化镓（GaN）高电子迁移率晶体管（HEMT）具有高开关速度和低导通电阻的优点，使其广泛用于高频应用中以实现高功率密度。三角形电流模式（TCM）调制已用于基于GaN的转换器中，以通过全范围零电压开关（ZVS）同时实现高功率密度和高效率。但是，随着开关频率的增加，空载时间的影响变得更加明显。同时，由于GaN HEMT的结电容器，最佳死区时间随关断电流而变化很大。不合适的空载时间会导致额外的损耗，不利于功率密度的进一步提高。为了使基于GaN HEMT的TCM转换器的死区时间损失最小化，本文提出了一种自适应死区控制策略。提出了一种精确的关断瞬态模型，以考虑非线性电容器来计算最佳死区时间。在此模型的基础上，建立了一个损耗模型，以评估涉及短路的空载时间对空载时间的影响。提出了一种新的TCM驱动信号产生方法，以提高停滞时间控制的精度并减少电流纹波。通过在TCM中重用检测信号，无需额外的传感器即可实现自适应死区时间控制。通过双脉冲测试验证了所提出的模型，该模型显示了计算的关闭时间与实验的关闭时间之间的最大误差在3 ns以下。所提出的自适应空载时间控制在基于GaN HEMT的升压转换器中实现。