Bi-directional multi-port inverter with high frequency link transformer
View Patent ↗This invention is a multi-port power converter where all ports are coupled through different windings of a high frequency transformer. Two or more, and typically all, ports have synchronized switching elements to allow the use of a high frequency transformer. This concept and type of converter is known. This invention mitigates a number of limitations in the present art and adds new capabilities that will allow applications to be served that would otherwise not have been practical. A novel circuit topology for a four-quadrant AC port is disclosed. A novel circuit topology for a unidirectional DC port with voltage boost capabilities is disclosed. A novel circuit topology for a unidirectional DC port with voltage buck capabilities is disclosed. A novel circuit for a high efficiency, high frequency, bi-directional, AC semiconductor switch is also disclosed.
1. A power converter apparatus comprising three or more ports, a transformer and a control circuit where one end of each port is connected to a distinct winding on a common transformer core and where the remaining end of each port is connected to a load or power source and where each port comprises an arrangement of capacitive or inductive energy storage elements and semiconductor switches where individual semiconductor switches are commanded on and off by said control circuit in a synchronous manner with semiconductor switches in other ports and where said power converter apparatus is further defined, as having one port dedicated to a storage battery, designated for reference herein as the battery port, having characteristics different from all other ports, specifically, semiconductor switches in the battery port operate in a free-running mode and provide frequency and phase references that are followed by synchronous switches in all remaining ports and the interface at the battery port transformer winding is that of a low impedance AC voltage source or sink, whereas the interface at the transformer windings of all other ports is that of a high impedance AC current source or sink and where these two distinct port types, battery and non-battery, enable energy transfer into or out of all non-battery ports simultaneously and in an autonomous manner in terms of energy transfer and where the net energy into or out of all non-battery ports charges or discharges the storage battery, respectively, via the battery port.