Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Impact of Grid Impedance Variations on Harmonic Emission of
  Grid-Connected Inverters   This paper addresses harmonic magnification due to resonance circuits
resulting from interaction between uncertain grid impedance and converter. The
source of harmonic may be either the grid or inverter. It is demonstrated that
unknown and unpredictable grid impedance may result in variable resonance
frequency, which challenges robust design of LCL filter of inverter.

22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys