Cooling of power semiconductors

A solid state circuit breaker, comprising:

• a first power semiconductor;
• a gate driver,
• wherein the gate driver is in electronic communication with the first power semiconductor, the gate driver extending from the first power semiconductor in a first direction,
• a first active cooling system,
• wherein the first active cooling system extends in a second direction perpendicular to the first direction;
• a fan;
• and
• a first bus bar disposed between the first active cooling system and the first power semiconductor, the first bus bar being sandwiched between a base plate of the first active cooling system and the first power semiconductor to conduct heat from the first power semiconductor to the first active cooling system through a thickness of the first bus bar, the first bus bar being metallic and extending at least a portion beyond the first active cooling system and the first power semiconductor in a third direction opposite the first direction and perpendicular to the second direction to provide a first exposed electrical connector;
• wherein the first active cooling system comprises an evaporator section pressed against the first bus bar and a condenser section extending beyond the first bus bar and the first power semiconductor in the second direction;
• and
• wherein the fan is located adjacent the condenser section to direct air through the condenser section;
• wherein the first bus bar comprises a copper plate to homogenize a temperature distribution on the base plate without substantially reducing a junction temperature to reduce thermal stress on the first power semiconductor.