A DC/DC converter includes: a first capacitor and a second capacitor coupled to a first node; a five-port network coupled to the first to fifth nodes; a transformer electrically connected to the fourth and fifth nodes; and a secondary side circuit electrically connected to a secondary winding of the transformer and coupled to a load; the control method includes: controlling, when the load is less than a preset value, switching states of multiple switches in the secondary side circuit, causing the transformer to be short-circuited for at least a first time period during a phase of stopping energy transmission; and controlling switching states of multiple switches in the five-port network during the first time period, causing current to flow from the five-port network to the first node or flow from the first node to the five-port network.