Electronic apparatus and surface temperature calculation method

1. An electronic apparatus comprising:

a housing;

a substrate disposed inside the housing;

a plurality of temperature sensors disposed on the substrate; and

a processor configured to perform a procedure including:

calculating heat source temperatures of a plurality of heat sources disposed on the substrate from measured temperatures measured by the temperature sensors, by using a first heat transfer model that assumes a steady state of heat transfer from the heat sources to the temperature sensors,

calculating a surface temperature of a surface of the housing from the heat source temperatures calculated by the first heat transfer model, by using a second heat transfer model including a first parameter representing a transient response of heat transfer from the heat sources to the temperature sensors and a second parameter representing a transient response of heat transfer from the heat sources to the surface, and

controlling at least part of operations of the heat sources, based on the calculated surface temperature;

wherein the first heat transfer model includes a first polynomial for calculating the heat source temperatures from the measured temperatures; and

the second heat transfer model includes a second polynomial for calculating the surface temperature from the heat source temperatures calculated by the first heat transfer model, calculation results of previous heat source temperatures, and calculation results of a previous surface temperature.

2. The electronic apparatus according to claim 1 , wherein:

the first parameter is a time constant representing response speed that indicates how fast changes in the heat source temperatures are reflected in the measured temperatures; and

the second parameter is a time constant representing response speed that indicates how fast the changes in the heat source temperatures are reflected in the surface temperature.

3. The electronic apparatus according to claim 1 , wherein:

the calculating of the surface temperature includes calculating, for a plurality of locations on the surface, a plurality of surface temperatures by using different second heat transfer models; and

the controlling is performed based on a maximum surface temperature amongst the calculated surface temperatures.

4. A surface temperature calculation method comprising:

acquiring, by a processor, measured temperatures measured by a plurality of temperature sensors disposed on a substrate provided inside a housing of an electronic apparatus;

calculating, by the processor, heat source temperatures of a plurality of heat sources disposed on the substrate from the measured temperatures by using a first heat transfer model that assumes a steady state of heat transfer from the heat sources to the temperature sensors;

calculating, by the processor, a surface temperature of a surface of the housing from the heat source temperatures calculated by the first heat transfer model, by using a second heat transfer model including a first parameter representing a transient response of heat transfer from the heat sources to the temperature sensors and a second parameter representing a transient response of heat transfer from the heat sources to the surface; and

controlling, by the processor, at least part of operations of the heat sources, based on the calculated surface temperature;

wherein the first heat transfer model includes a first polynomial for calculating the heat source temperatures from the measured temperatures; and

the second heat transfer model includes a second polynomial for calculating the surface temperature from the heat source temperatures calculated by the first heat transfer model, calculation results of previous heat source temperatures, and calculation results of a previous surface temperature.

5. A non-transitory computer-readable storage medium storing a computer program that causes a computer to perform a procedure comprising:

acquiring measured temperatures measured by a plurality of temperature sensors disposed on a substrate provided inside a housing of an electronic apparatus;

calculating heat source temperatures of a plurality of heat sources disposed on the substrate from the measured temperatures by using a first heat transfer model that assumes a steady state of heat transfer from the heat sources to the temperature sensors;

calculating a surface temperature of a surface of the housing from the heat source temperatures calculated by the first heat transfer model, by using a second heat transfer model including a first parameter representing a transient response of heat transfer from the heat sources to the temperature sensors and a second parameter representing a transient response of heat transfer from the heat sources to the surface; and

controlling at least part of operations of the heat sources, based on the calculated surface temperature;

wherein the first heat transfer model includes a first polynomial for calculating the heat source temperatures from the measured temperatures; and

the second heat transfer model includes a second polynomial for calculating the surface temperature from the heat source temperatures calculated by the first heat transfer model, calculation results of previous heat source temperatures, and calculation results of a previous surface temperature.