如何在Power shell中将Start Process用作FileSystemWatcher的操作

我能够成功使用System.IO.FileSystemWatcher来查看已创建文件的文件夹和子目录，但是当我尝试使用Start Process运行批处理文件时，它会运行一次，但之后再也不会触发。我从这里修改了答案。

这是我的powershell脚本

$watcher = New-Object System.IO.FileSystemWatcher
$watcher.Path = "C:\lectures"
$watcher.Filter = "*.*"
$watcher.IncludeSubdirectories = $true
$watcher.EnableRaisingEvents = $true  

$action = { $path = $Event.SourceEventArgs.FullPath
            Write-Host "Event Fired"
            $ext = [io.path]::GetExtension($path)
            if($ext -eq ".wma"){
                $file = [io.path]::GetFileNameWithoutExtension($path)
                $folder = Split-Path(Split-Path $path -Parent) -Leaf
                $date = Get-Date -UFormat "%Y-%m-%d"
                $newName = $folder + "_" + $date + $ext
                $newPath = Rename-Item -path $path -newname $newName -PassThru
                Start-Process "C:\lectures\deploy.bat" $newPath
            }
          }

Register-ObjectEvent $watcher "Created" -Action $action
while ($true) {
    Write-Host "Still Alive"
    sleep 5
}

这是我正在运行的批处理文件

@echo off
CD %~dp1
ffmpeg -i %~nx1 %~n1.mp3 -loglevel panic
del %1
REM Winscp.com /ini=null /script=uploadScript.txt /parameter %~n1.mp3

powershell脚本在运行进程后继续运行，并且该进程似乎正在正常退出。如何让它继续处理事件？