Was Oliver Cromwell after Power for Himself?

O the 17th March 1649, King Charles I was dead and the 'Rump Parliament' abolished the monarchy. The following period would be known as the interregnum as England became a republic ruled by the leader of the army; Oliver Cromwell. Oliver Cromwell was known for criticising Charles' ruthlessness and abuses of his power but it is believed by some that Cromwell was after power himself.
The first action of Cromwell's that led me to believe that he was after power was when he stood outside of Parliament and barred all of the MPs who opposed his beliefs from entering. …