Hybrid AC Power Source Based on Modular Multilevel Converter and Linear Amplifier

This paper presents a hybrid amplifier for an ac power source (ACPS). The topology is composed of a modular multilevel converter (MMC), operating as main amplifier, connected in series with a linear power amplifier (LPA), which operates as correction amplifier. This way, it is possible to gather the modularity, reliability, and high efficiency provided by the MMC and the high waveform fidelity provided by the LPA. Additionally, it is possible to reproduce a voltage waveform with a high bandwidth and, differently from previous works, with a topology that requires a unique dc voltage source for the main amplifier. The inner current and the submodule capacitor voltages are controlled in the MMC. Meanwhile, the LPA is controlled to define the output voltage. A design methodology and experimental results are included to demonstrate the operation of the ACPS topology.