If you are looking to backup virtual machines of Hyper-v or VMWare and looking for a free software to do it, you might want to consider Veeam (www.Veeam,com). One of the features that wont be available since you will be using the free edition is being able to schedule backup Jobs from within Veeam. The free edition will allow you to run backup on demand if that is what you are looking for.
You can schedule backup jobs using Powershell and Windows schedule task. We will post an example on how to do that in the coming days.