Hysteresis Current Control for Multilevel Converter in Parallel-Form Switch-Linear Hybrid Envelope Tracking Power Supply
Hysteresis Current Control for Multilevel Converter in Parallel-Form Switch-Linear Hybrid Envelope Tracking Power Supply
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DOI：
10.1109/tpel.2018.2835640
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发表时间：
2019-02
影响因子：
6.7
通讯作者：
Yazhou Wang;X. Ruan;Yang Leng-;Ying Li
中科院分区：
文献类型：
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作者：
Yazhou Wang;X. Ruan;Yang Leng-;Ying Li
开关线性混合包络跟踪电源由线性放大器和开关变换器并联组成。开关模式转换器通常由具有滞环电流控制的降压转换器来实现。然而，当负载电流的压摆率具有宽的变化范围时，降压转换器的负载电流和电感器电流的压摆率不能很好地匹配。不匹配的压摆率将导致降压转换器的高开关频率或线性放大器的大损耗，这降低了整体效率。本文采用多电平变换器代替并联型SLH ET电源中的降压变换器，并提出滞环电流控制方案，使多电平变换器动态调整电感电流摆率以接近负载电流摆率，从而提高整体效率。给出了多电平变换器中电感、电流滞环、电压电平个数和电压电平值等与效率相关的参数的优化设计。研制了一种并联式滞环电流控制多电平变换器SLH ET电源样机，并进行了实验室测试。在跟踪带宽为5MHz的宽带码分多址信号包络，输出平均功率为18W时，测得的总效率为79.4%，比滞环电流控制降压变换器的效率提高了3.8%。
Parallel-form switch-linear hybrid (SLH) envelope tracking (ET) power supply is constituted by a linear amplifier and a switched-mode converter connected in parallel. The switched-mode converter is usually implemented by a buck converter with hysteresis current control. However, the slew rates of the load current and the inductor current of the buck converter cannot match well when the slew rate of the load current has a wide variation range. The unmatched slew rates will lead to a high switching frequency of the buck converter or a large loss of the linear amplifier, which degrades the overall efficiency. In this paper, a multilevel converter is adopted to replace the buck converter in the parallel-form SLH ET power supply, and the hysteresis current control scheme is proposed for the multilevel converter to dynamically adjust its inductor current slew rate to approach that of the load current to improve the overall efficiency. The optimal design for the efficiency-related parameters including the inductor, the current hysteresis, and the number and values of the voltage levels in the multilevel converter is given. A prototype of the parallel-form SLH ET power supply with hysteresis current controlled multilevel converter is fabricated and tested in the lab. The measured overall efficiency is 79.4% when tracking the envelope of wideband code division multiple access signal with 5 MHz bandwidth and outputs 18 W average power, and a 3.8% efficiency improvement is achieved over that with the hysteresis current controlled buck converter.