Modulation-Enhanced Nearest-Level Quantization for a Wide Output Bandwidth

01 Mar 2024 - Durham

Selected Publications: Straight to the Point is a section where I introduce my publications with words that are as direct and simple as possible. I will assume that you already know the context of this paper.

@ARTICLE{10336557,
  author={Zhang, Jinshui and Tian, Xiaoyang and Wang, Boshuo and Peterchev, Angel V. and Goetz, Stefan M.},
  journal={IEEE Transactions on Power Electronics}, 
  title={Modulation-Enhanced Nearest-Level Quantization for a Wide Output Bandwidth}, 
  year={2024},
  volume={39},
  number={3},
  pages={3289-3299},
  doi={10.1109/TPEL.2023.3338109}}

Prerequisite Knowledge

Quantizer is a process where modular multilevel converter digitizes continuous input to discrete output level commands.
Nearest level modulation has low switching rate but low quantizing quality.
Carrier based PWM has high switching rate but high quantizing quality.

Novelty: A quantizing method combining Nearest level modulation and an one-bit PWM approach. Instead a simple combination, we realized that one-bit PWM only works if the input signal has a constrained bandwidth, otherwise this quantizer method is equivalent to level-shifted-carrier PWM. Therefore, we added a low-pass filter before feeding the residue of NLM to PWM.

Limits: The low-pass filter works the best when the input signal is known so we can do a filtfilt (forward&backward filter to cancel time delay), and not as well on unknown signal. Yet, it’s still better than either PSC-PWM, LSC-PWM or NLM methods.