Optimized Design of the Multilevel Converter in Series-Form Switch-Linear Hybrid Envelope-Tracking Power Supply
Optimized Design of the Multilevel Converter in Series-Form Switch-Linear Hybrid Envelope-Tracking Power Supply
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DOI：
10.1109/tie.2016.2565459
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发表时间：
2016-05
影响因子：
7.7
通讯作者：
Yazhou Wang;Q. Jin;X. Ruan
中科院分区：
文献类型：
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作者：
Yazhou Wang;Q. Jin;X. Ruan
在现代无线电通信中，射频（RF）信号的包络具有较大的峰均功率比。这就需要采用线性功率放大器 (PA)。为了实现线性 PA 的高效率，采用了包络跟踪 (ET) 技术，该技术为 PA 提供跟踪所传输 RF 信号包络的电源电压，而不是恒定电压。本文重点研究串联形式的开关-线性混合ET电源，其中开关模式变换器采用多电平变换器。提出了在保证输出电压线性的前提下选择设定电压的方法。此外，使用基于包络信号的概率密度函数的精确损耗模型来优化多电平转换器的电压电平的值和数量。此外，还提出了脉冲消隐方法以进一步提高系统效率。最后，搭建了一个用于跟踪宽带码分多址包络信号的样机，其带宽为5 MHz，输出电压为12-27 V，平均输出功率为4 W，峰值输出功率为10 W。实验结果表明，ET电源的输出电压能够准确跟踪基准电压，系统效率可达76%。
In modern radio communications, the envelope of radio frequency (RF) signal features with large peak-to-average power ratio. This necessitates the adoption of linear power amplifiers (PAs). In order to achieve a high efficiency for linear PAs, envelope-tracking (ET) technique is employed, which provides PAs with a supply voltage that tracks the envelope of the transmitted RF signal instead of a constant voltage. This paper focuses on the series-form switch-linear hybrid ET power supply, where the switching-mode converter uses a multilevel converter. The method to select the setting voltages under the premise of ensuring the linearity of output voltage is presented. In addition, the values and number of the voltage levels of the multilevel converter are optimized using a precise loss model based on the probability density function of the envelope signal. Besides, the pulse-blank method is proposed to improve the system efficiency further. Finally, a prototype is built aiming for tracking the envelope signal of wideband code division multiple access, with 5-MHz bandwidth, 12-27 V output voltage, 4 W average, and 10 W peak output power. The experimental results show that the output voltage of the ET power supply tracks the reference accurately and the system efficiency can reach 76%.