PowerShell script to disable Windows power management on all currently connected serial ports, including most (if not all) USB devices and adapters.

DisableUSBPowerManagement.ps1

# PowerShell script to disable Windows power management on all currently connected serial ports, including USB adapters
# In simpler terms, it prevents Windows from turning off connected serial devices to save power.
# Equivalent to right-clicking on a serial port device in Device Manager > Properties > "Power Management" Tab > Unchecking "Allow the computer to turn off this device to save power."

# To run it you have a few options:

# .\SerialPowerMgmt.ps1 -Enable - this would enable power management (default)
# .\SerialPowerMgmt.ps1 -Disable - this would disable power management
# .\SerialPowerMgmt.ps1 -Disable -DryRun - just for testing, no change is done

param(
    [switch]$Disable,
    [switch]$Enable,
    [switch]$DryRun
)

if (-not ($Disable -or $Enable)) {
    Write-Error "You must specify either -Disable or -Enable."
    exit 1
}

$serials = Get-CimInstance -ClassName Win32_SerialPort |
           Select-Object Name, DeviceID, PNPDeviceID

$powerMgmt = Get-CimInstance -Namespace root\wmi -ClassName MSPower_DeviceEnable

foreach ($p in $powerMgmt) {
    foreach ($s in $serials) {
        if ([string]::IsNullOrWhiteSpace($s.PNPDeviceID)) { continue }

        $pattern = [regex]::Escape($s.PNPDeviceID)

        if ($p.InstanceName -match $pattern) {
            $desired = if ($Disable) { $false } else { $true }

            if ($p.Enable -ne $desired) {
                if ($DryRun) {
                    Write-Host "[DRYRUN] Would set $($s.Name) ($($s.DeviceID)) to Enable=$desired"
                } else {
                    try {
                        Set-CimInstance -InputObject $p -Property @{ Enable = $desired } -ErrorAction Stop
                        Write-Host "Set power mgmt for $($s.Name) ($($s.DeviceID)) to Enable=$desired"
                    } catch {
                        Write-Warning "Failed on $($s.Name) ($($s.DeviceID)): $($_.Exception.Message)"
                    }
                }
            } else {
                Write-Host "Already in desired state: $($s.Name) ($($s.DeviceID)) (Enable=$desired)"
            }
        }
    }
}