PowerShell script for partition refresh

function GetAuthToken
{
    if(-not (Get-Module AzureRm.Profile)) {    Import-Module AzureRm.Profile    }
    $clientId = "<your app id>"
    $redirectUri = "urn:ietf:wg:oauth:2.0:oob"
    $resourceAppIdURI = "https://analysis.windows.net/powerbi/api"
    $authority = "https://login.microsoftonline.com/common/oauth2/authorize";
    $authContext = New-Object "Microsoft.IdentityModel.Clients.ActiveDirectory.AuthenticationContext" -ArgumentList $authority
    $authResult = $authContext.AcquireToken($resourceAppIdURI, $clientId, $redirectUri, "Auto")
    return $authResult
}

# Get the auth token from AAD
$token = GetAuthToken

# Building Rest API header with authorization token
$authHeader = @{
    'Content-Type'='application/json'
    'Authorization'=$token.CreateAuthorizationHeader()
}

once you have that you can use it in the auth header for your refresh requests.  Use jwt.io to validate that the token has the right scope.