Abstract: A system has a DC bus circuit with first and second terminals, an intermediate node, first and second capacitors, first and second depletion mode FETs, and first and second switching control circuits, where the first depletion mode FET has a drain coupled to the first bus terminal, a source, and a gate coupled to the intermediate node, the second depletion mode FET has a drain coupled to the intermediate node, a source, and a gate coupled to the second bus terminal, the first switching control circuit turns the first depletion mode FET off responsive to a first capacitor voltage of the first bus capacitor being less than or equal to a second capacitor voltage of the second bus capacitor, and the second switching control circuit turns the second depletion mode FET off responsive to the first capacitor voltage being greater than or equal to the second capacitor voltage.

Abstract: Thermal monitoring and analysis of conditions in a power electronic system include sensing of thermal parameters of interest, such as temperature and humidity in an enclosure housing power electronic components. The components are cooled by a liquid coolant flow from a chiller through chiller plates associated with the power electronic components. Air is circulated through the enclosure for heat rejection from the chiller plates. Based on the sensed parameters, factors such as relative humidity and dew point of the cooling air may be computed and evaluated to determine the potential for condensation. Alarms, notices, or recommendations may be output for regulation of the chiller to avoid condensation. The system may also provide for evaluation of installation errors, and degradation of performance over time.

Abstract: A system has a DC bus circuit with first and second terminals, an intermediate node, first and second capacitors, first and second depletion mode FETs, and first and second switching control circuits, where the first depletion mode FET has a drain coupled to the first bus terminal, a source, and a gate coupled to the intermediate node, the second depletion mode FET has a drain coupled to the intermediate node, a source, and a gate coupled to the second bus terminal, the first switching control circuit turns the first depletion mode FET off responsive to a first capacitor voltage of the first bus capacitor being less than or equal to a second capacitor voltage of the second bus capacitor, and the second switching control circuit turns the second depletion mode FET off responsive to the first capacitor voltage being greater than or equal to the second capacitor voltage.

Abstract: Thermal monitoring and analysis of conditions in a power electronic system include sensing of thermal parameters of interest, such as temperature and humidity in an enclosure housing power electronic components. The components are cooled by a liquid coolant flow from a chiller through chiller plates associated with the power electronic components. Air is circulated through the enclosure for heat rejection from the chiller plates. Based on the sensed parameters, factors such as relative humidity and dew point of the cooling air may be computed and evaluated to determine the potential for condensation. Alarms, notices, or recommendations may be output for regulation of the chiller to avoid condensation. The system may also provide for evaluation of installation errors, and degradation of performance over time.