POWER SUPPLY SYSTEM AND MOVING BODY

A power supply system includes: a DC power supply ; a variable voltage power supply serving as an isolated bidirectional DC/DC converter that outputs power of a variable voltage E from a pair of secondary-side input/output terminals and ; a positive electrode power line and a negative electrode power line that are connected to both electrodes of the DC power supply ; a switching circuit including a plurality of arm switching elements , and that connect the power lines and and a load ; a backflow prevention switching element that is provided on the positive electrode power line between the pair of secondary-side input/output terminals and ; a power supply driver that operates the variable voltage power supply and the backflow prevention switching element ; and a switching circuit driver