Bi-directional dc/dc converter

A bi-directional DC/DC converter having an input terminal adapted for connecting to a power source and an output terminal adapted for connecting to a load, said DC/DC converter comprising:

• a module adapted for connecting between the DC/DC converter input terminal and the DC/DC converter output terminal, said module comprising:
• a transformer having a primary winding and a secondary winding, said transformer generating a leakage inductance;
• a primary side circuit connected between the primary winding and the DC/DC converter input terminal, said primary side circuit including a primary set of switches connected in an H-bridge configuration with the primary winding;
• a secondary side circuit connected between the secondary winding and the DC/DC converter output terminal, said secondary side circuit including a high voltage bus, a low voltage bus, and a secondary set of switches connected in an H-bridge configuration, wherein the H-bridge configuration of the secondary set of switches has a first leg and a second leg, said first leg and said second leg are connected between the high voltage bus and the low voltage bus of the secondary side circuit and coupled together by the secondary winding, said secondary set of switches including a first switch and a second switch forming the first leg, said first switch connected to the high voltage bus and said second switch connected to the low voltage bus, said secondary set of switches including a third switch and a fourth switch forming the second leg, said third switch connected to the high voltage bus and said fourth switch connected to the low voltage bus;
• a snubber circuit connected across the secondary winding for absorbing energy from the leakage inductance;
• and
• a module control connected to the primary side circuit for controlling the primary set of switches and to the secondary side circuit for controlling the secondary set of switches, said module control configured to alternately switch the first and the third switches and to alternately switch the second and fourth switches, said module control further configured to switch the fourth switch following a delay period from the switching of the first switch, and to switch the second switch following the delay period from the switching of the third switch, said delay period causing leakage inductance current to reverse.

A bi-directional battery testing apparatus comprising:

• a power input adapted for connecting to a power source;
• a load output adapted for connecting to a load;
• a plurality of modules connected between the power input and the load output, each module of said plurality of modules connected in parallel with each other module of said plurality of modules, wherein each module comprises a primary set of switches having an H-bridge configuration, a secondary set of switches having an H-bridge configuration, a transformer isolating said primary set of switches from said secondary set of switches, and a hysteretic control for driving said secondary set of switches to control a module output parameter;
• a current sensing component connected to the load output for sensing a total current at said load output and for generating a current feedback signal representative of the sensed total current;
• and
• a controller for receiving the current feedback signal from the current sensing component and responsive to said receiving for providing a current module command signal to the hysteretic control of each of the plurality of modules, said current module command signal is based on a difference between the sensed total current and a target current, wherein said hysteretic control drives the secondary set of switches as a function of said current module command signal to control a module output current.