Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Novel Optimal Modulation Strategy for Modular Multilevel Converter
  Based HVDC Systems   Unlike conventional converters, modular multilevel converter (MMC) has a
higher switching frequency -- which has direct implication on important
parameters like converter loss and reliability -- mainly due to increased
number of switching components. However, conventional switching techniques,
where submodule sorting is just based on capacitor voltage balancing, are not
able to achieve switching frequency reduction objective. A novel modulation
algorithm for modular multilevel converters (MMCs) is proposed in this paper to
reduce the switching frequency of MMC operation by defining a constrained
multi-objective optimization model. The optimized switching algorithm
incorporates all control objectives required for the proper operation of MMC
and adds new constraints to limit the number of submodule switching events at
each time step. Variation of severity of the constraints leads to a desired
level of controllability in MMC switching algorithm to trade-off between
capacitor voltage regulation and switching frequency reduction. Finally,
performance of the proposed algorithm is validated against a seven-level
back-to-back MMC-HVDC system under various operating conditions.

16
The categories of this paper are: stat
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex