Refresh wp.media after ajax call

So, I followed your links and this is working for me. This test works the same for my upload callbacks so hopefully it works for you.

In the iframe

function myTab_save_frame()
{
    global $redir_tab;

    $redir_tab = 'mytab';

    media_upload_header(); ?>

    <button>Test Trigger</button>

    <script>
        var switchAndReload = function() {

            // get wp outside iframe

            var wp = parent.wp;

            // switch tabs (required for the code below)

            wp.media.frame.setState('insert');

            // refresh

            if( wp.media.frame.content.get() !== null) {
                wp.media.frame.content.get().collection.props.set({ignore: (+ new Date())});
                wp.media.frame.content.get().options.selection.reset();
            } else {
                wp.media.frame.library.props.set ({ignore: (+ new Date())});
            }
        };

        jQuery('button').on('click', function(evt){

            // do upload logic...

            // upload completed.

            // refresh library!

            switchAndReload();
        });
    </script>
    <?php 
}