多电平D类功率放大器的工作原理

本文介绍了一种新颖的基于级联型多电平拓扑结构的开关型功率放大器，采用单极倍频相移PWM技术，其开关频率是单个单元开关频率的2N倍，总的输出电压波纹小，比较了采用相移PWM技术和位移PWM技术的多电平输出信号的性能特点，分析了级联型多电平D类功率放大器的工作原理，之后研制了一台级联型多电平的D类功率放大器。研究结果表明采用单极倍频相移三角载波PWM法的级联型多电平D类功率放大器具有良好的跟踪性和稳定性。

The Cascade Multilevel Class-D Power Amplifier With the Carrier-Based Phase-Shifted Modulation

A novel switch-mode power amplifier based on a cascade multicell multilevel circuit topology is introduced in the paper. By application of the concept of multicell topology being operated in a unipolar phase-shifted PWM control to switch-mode amplifier system, the effective switching of output results in 2N times the switching frequency of each full-bridge. Due to the Carrier-Based phase-shifted modulation of the individual switching cells, the output voltage ripple of the total system is considerably small. The paper analyzes the advanced characteristic of cascade multilevel technique. Two carrier-based PWM schemes, phase-shifted and level-shifted modulations, are analyzed and their performance is compared, and then a cascade multilevel class-D power amplifier is built in the laboratory. The results of measurements show an excellent response and stability.