Typically an expansion valve in an A/C circuit is controlled by taking a desired superheating temperature as the target. But for electronic expansion valves it would also be possible to control the valve by taking a desired subcooling at the condenser as the target. This example shows how such a configuration can be modeled by using the signal path to iteratively calculate the appropriate cross section of the expansion valve. The calculation method is based on the Newton method and works for both steady state and transient models. With the help of an appropriate map of desired subcooling temperatures the system can then be set up for optimal COP values.
The idea of using a Newton method in the signal path can be applied in many different applications, whenever some control of an input parameter is required and the built-in optimization cannot be used.
Usable from release: KULI 14