In a harmonic (AC) electric circuit analysis, you determine the voltage and current distribution in an electric circuit that is subjected to applied AC source voltages or currents. Harmonic circuit analyses allow all circuit components.
To do this, you simply follow the procedure described in Building a Circuit.
You need to define the analysis type and options, apply loads, and initiate the finite element solution. To accomplish these tasks, follow the steps listed below.
To enter the SOLUTION processor, use either of the following:
To specify the analysis type, do either of the following:
In the GUI, choose menu path and choose a Harmonic analysis.
If this is a new analysis, issue the command ANTYPE,HARMIC,NEW.
To specify the equation solver to use, use either of the following:
Only the sparse solvers is available for problems using the CIRCU124 element.
You need to specify how the harmonic voltage and current are listed in the printed output, Jobname.out. You can choose either real and imaginary parts (default) or amplitudes and phase angles.
To specify the listing format, use one of the following:
Normally, you specify source loads for circuits in the Circuit Builder, as element real constants. Besides the source loads, the only other "load" is a VOLT = 0 specification at the ground nodes. To specify VOLT = 0, use either of the following:
Should you need to modify the source loads, use one of the following:
The RMODIF command has no GUI equivalent.
You can specify one dynamics option, the operating frequency (in Hz) of the harmonic loads. To specify the frequency, use either method shown below:
The only general option you can specify is the number of harmonic solutions. You can requests any number of solutions to be calculated, and those solutions (or substeps) will be spaced evenly within the specified operating frequency. For example, if you specify 10 solutions in the range 50 to 60 Hz, the program will calculate the response at 51, 52, 53, ..., 59, and 60 Hz. Mechanical APDL calculates no response at the lower end of the frequency range.
To specify the number of harmonic solutions, use either of the following:
Use either the SAVE command or the SAVE_DB button on the Toolbar to save a backup copy of the database.
To start calculating the solution, use one of the following:
To leave the SOLUTION processor, use one of the following:
The program writes results from a harmonic circuit analysis to the results file, Jobname.rth. The results are out-of-phase with the input source loads (that is, they lag the input source loads), so they are complex in nature. The results are calculated and stored in terms of real and imaginary components, and consist of two types of primary data: nodal voltages (VOLT) and nodal currents (CURR).
The derived data for a harmonic circuit analysis are the same as for a static circuit analysis, and you use the same procedures to review results. However, for harmonic analyses, you can also store results per element in the element table and list them using one of the following: