Method of junction temperature determination and control utilizing heat flow

A method for monitoring the temperature of the heat producing portion of an electrical current carrying device with a plurality of thermal dissipation paths comprising the steps,

• producing a signal relating to the temperature at one point along each thermal dissipation path associated with said electrical current carrying device,
• determining the thermal conductivity between said heat producing portion of said electrical current carrying device and each temperature measurement point,
• producing a signal relating to the total power dissipated by the electrical current carrying device as heat, and
• combining said signals relating to temperature, said thermal conductivities, and said power measurement to produce a signal relating to the temperature of said heat producing portion of said electrical current carrying device.

An apparatus for monitoring the temperature of the heat producing portion of an electrical current carrying device comprising,

• means for establishing a temperature at one point along a thermal dissipation path associated with said electrical current carrying device,
• means for determining the heat flux between the heat producing portion of said electrical current carrying device and said temperature measurement point,
• means for determining the thermal conductivity between said heat producing portion of said electrical current carrying device and said temperature measurement point, and
• means for calculating the temperature of said heat producing portion of said electrical current carrying device based upon said temperature on the thermal dissipation path, said heat flux, and said thermal conductivity,
• wherein said heat flux is determined by measuring any two values chosen from the group consisting of the current flowing through the device, the electrical impedance of the device, and the voltage across the device.

An apparatus for monitoring the temperature of the heat producing portion of an electrical current carrying device comprising,

• means for establishing a temperature at one point along a thermal dissipation path associated with said electrical current carrying device,
• means for determining the heat flux between the heat producing portion of said electrical current carrying device and said temperature measurement point,
• means for determining the thermal conductivity between said heat producing portion of said electrical current carrying device and said temperature measurement point, and
• means for calculating the temperature of said heat producing portion of said electrical current carrying device based upon said temperature on the thermal dissipation path, said heat flux, and said thermal conductivity,
• wherein the heat flux is measured utilizing a heat flow sensor comprising a first integrating temperature sensing means, a second integrating temperature sensing means that is offset by a known distance from the first in the direction of heat flow, and a means to mount such sensor to a thermal dissipation path.

An apparatus for monitoring the temperature of the heat producing portion of an electrical current carrying device containing a plurality of thermal dissipation paths comprising,

• means for establishing a temperature at one point along each thermal dissipation path associated with said electrical current carrying device,
• means for determining the thermal conductivity between said heat producing portion of said electrical current carrying device and each temperature measurement point,
• means for determining the total power dissipated by the electrical current carrying device as heat, and
• means for calculating the temperature of said heat producing portion of said electrical current carrying device based upon said thermal path temperature measurements, said thermal conductivities, and said power measurement.