There are three components to vCenter Converter - The Server, Agent and the Worker
In order to enable verbose logging on each of the components, backup and edit the below files at:
%programdata%\VMware\VMware vCenter Converter Standalone\
In each file change the log level from “info” to “verbose” under the following element
<log> ... <level>info</level> </log>
Restart the converter services to apply the above changes.