## 2 Innovative System Configuration, Dynamics Equations, and the Simulator
### Control Strategies for the IHTMS  
To manage the optimal temperatures of emulated lithium battery and the PEMFC, the rule-based control strategies were adopted for actuators: electromagnetic valves, proportional valve, electric-controlled radiator, and the coolant pump. The rules were designed as follows:  
(a) Electromagnetic valves  
If \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\), \(V_{switch}=0\);  
Elseif \(T_{bat,a}\geq T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\), \(V_{switch}=0\)  
Elseif \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}\geq T_{fc,g}\), \(V_{switch}=1\)  
Elseif \(T_{bat,a}>T_{bat,g}\) and \(T_{fc,a}>T_{fc,g}\), \(V_{switch}=1\)  
End  
(b) Proportional valve  
If \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\), \(V_{pv}=1.98\);  
Elseif \(T_{bat,a}\geq T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\),\(V_{pv}=1.8\);  
Elseif \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}\geq T_{fc,g}\), \(V_{pv}=V_{pv}+K_{pv}\times\Delta t_{pv}\); (\(V_{pv,max}=3.4\))  
Elseif \(T_{bat,a}>T_{bat,g}\) and \(T_{fc,a}>T_{fc,g}\), \(V_{pv}=V_{pv}+K_{pv}\times\Delta t_{pv}\); (\(V_{pv,max}=3.4\))  
End  
(c) Electric-controlled radiator  
If \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\), \(V_{fan}=0\);  
Elseif \(T_{bat,a}\geq T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\),\(V_{fan}=0\);  
Elseif \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}\geq T_{fc,g}\),  
\(V_{fan}=V_{fan}+K_{fan}\times\Delta t_{fan}\); (\(V_{pv,max}=10\))  
Elseif \(T_{bat,a}>T_{bat,g}\) and \(T_{fc,a}>T_{fc,g}\),  
\(V_{fan}=V_{fan}+K_{fan}\times\Delta t_{fan}\); (\(V_{pv,max}=10\))  
End  
Figure 3: Decomposition of the HTMS. (d) Coolant pump  
If \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\), \(V_{pump}=1.7\);  
Elseif \(T_{bat,a}\geq T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\),  
\(V_{pump}=V_{pump}+K_{pump}\times\Delta t_{pump}\); (\(V_{pump,max}=10\))  
Elseif \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}\geq T_{fc,g}\),  
\(V_{pump}=V_{pump}+K_{pump}\times\Delta t_{pump}\); (\(V_{pump,max}=10\))  
Elseif \(T_{bat,a}>T_{bat,g}\) and \(T_{fc,a}>T_{fc,g}\),  
\(V_{pump}=V_{pump}+K_{pump}\times\Delta t_{pump}\); (\(V_{pump,max}=10\))  
End  
where \(K\), \(\Delta t\), \(V\) represent gain, sampling time and voltage, respectively; subscripts \(a\), \(g\), \(pv\), \(pump\), \(fan\), \(switch\) represent actual, goal, proportional valve, coolant pump, radiator fan, electromagnetic switch, respectively. First of all, four control modes (Mode 1 to Mode 4) were defined in advance. When \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\), it was in Mode 1. When \(T_{bat,a}\geq T_{bat,g}\) and \(T_{fc,a}<T_{fc,g}\), it was in Mode 2. As \(T_{bat,a}<T_{bat,g}\) and \(T_{fc,a}\geq T_{fc,g}\), the operation mode is Mode 3, and Mode 4 is when \(T_{bat,a}>T_{bat,g}\) and \(T_{fc,a}\geq T_{fc,g}\). The explanations for control strategies were described sequentially: (a) Electromagnetic valves: as Mode 1 or Mode 2, the fuel cell temperature was below the target value, 55 \({}^{\circ}\)C. To reach the goal rapidly, \(V_{switch}=0\) leads to the inner-loop mode. As Mode 3 or Mode 4, the system temperature was averagely high so that \(V_{switch}=1\) to enter the outer-loop mode. For (b) Proportional valve: at Mode 1, the proportional valve voltage \(V_{pv}=1.98\), where 75% coolant was sent to the fuel cell while 25% was sent to the battery, so that the two optimal temperatures will be reached nearly simultaneously. When Mode 2 was reached, \(V_{pv}=1.8\) so that more coolant was delivered to the battery and the target fuel cell temperature will be met faster. Contrarily, if the fuel cell temperature exceeded the target value, \(V_{pv}=3.4\) to provide more heat dissipation capacity to the fuel cell. For (c) Electric-controlled radiator: at Mode 1 or Mode 2, since the system temperature was averagely low so that \(V_{fan}=0\); at Mode 3 or Mode 4, because the system temperature was high, the fan activated to remove more waste heat. For (d) Coolant pump: at Mode 1, \(V_{pump}=1.7\) so that the coolant flow rate was 0.4 L/min. as the lowest speed to accelerate the temperature increasing speed.