While building out an automation process I needed to convert a xlsx file to a csv file for further parsing within powershell. Unfortunately this is not built into powershell, and excel needs to be installed on the system for this to work. Although its not a powershell cmdlet the solution is quite simple:
Function ExcelCSV ($File)
$excelFile = "$pwd\" + $File + ".xlsx"
$Excel = New-Object -ComObject Excel.Application
$Excel.Visible = $false
$Excel.DisplayAlerts = $false
$wb = $Excel.Workbooks.Open($excelFile)
foreach ($ws in $wb.Worksheets)
$ws.SaveAs("$pwd\" + $File + ".csv", 6)
$FileName = "Book1"
ExcelCSV -File "$FileName"
For the file location I leverage $pwd, this can be altered to what ever is needed but for a test script this is most likely the easiest way to get it running to test. The script will make a csv file from the xlsx specified using the exact same file name.