The router doesn't control the local IP, Windows does that. Go into the Control Panel, then Network and Internet, then Network Connections, right click on your local connection, select Properties, select IPV4. Then click the Properties button. This is where you can set the local IP. When you reboot it'll always use that IP. If you don't do this it seems to randomly pick a new IP with every reboot.
When I first did this I was suspicious that at some point there might be a conflict with other devices on my LAN but that was a year ago and it's been fine.