2.1. Commands Used in an HBM Analysis

The main commands used to specify a Harmonic Balance Method (HBM) analysis are listed below. For a more detailed description of available options, their default settings, recommendations, and a discussion of how various options affect the analysis, see also HBM Solution Controls. For an example of usage, see Harmonic Balance Method Examples.

Preprocessor (/PREP7) or Solution (/SOLU) commands
HROPTIssue HROPT,HBM,NH to specify:

  • the harmonic balance solution method (Method = HBM)

  • number of harmonics to be included in the analysis, an integer NH within the range 1 ≤ NH ≤ 30 (defaults to 1).

HBMOPTTo specify solution options. This command must be issued in the solution (/SOLU) processor. Note that for cyclic symmetry analysis with harmonic index greater than 0, you must use HBMOPT,CYCLIC with CYCkey=1.
HARFRQTo define the frequency range by setting FREQB and FREQE to the beginning and end frequency (Hz). Note the following:

  • FREQB may be greater than FREQE for a decreasing frequency sweep. However, FREQB ≤ FREQE is enforced if no continuation method is used (HBMOPT,CONTSET,OFF).

  • Specifying an array of frequency values (FREQARR) is not supported.

NSUBSTTo specify the number of substeps, NSBSTP, if no continuation method is used (only applicable for HBMOPT,CONTSET,OFF).