I am currently trying to expand the Electric Vehicle Thermal Management model by adding a heat pump for heating operation instead of the PTC element. I would like to have the two-phase fluid flow through some kind of valve into another circuit. Since there seems to be no closing valves for 2P, I have tried to insert a valve orifice.
Below you can see my modified circuit.
Since it doesn't work like that yet, I created a much simplified model. Now I simply want to test the two shutoff valves.
SV1 should be open and SV2 closed. I realize this via a MATLAB function in the control block. cmd_SV1 or cmd_SV2 is either 1 or 0 and thus opens or closes the orifice.
function [cmd_SV1,cmd_SV2] = modefunction(delta_T_cabin)
if delta_T_cabin > 0
cmd_SV1 = 1;
cmd_SV2 = 0;
cmd_SV1 = 0;
cmd_SV2 = 1;
- Cabin temperature: 30 °C
- Target temperature: 21 °C
- delta_T_cabin = 9 °C (For the original model)
Now, strangely enough, the following case occurs: With two valves, a temperature difference of -21 °C is passed to the function because the cabin temperature is suddenly 0 °C. This means that my valves are not controlled correctly and an error occurs.
Now my questions:
Is it possible to switch a two-phase fluid like this at all? If so, how do I solve the problem? Why is my cabin temperature suddenly changed? Without SV2 but with SV1 the simulation runs without any problems.
Thanks for your help!