Reduced Order Modeling for Cooling -Battery/Electronics/Electric Machine Case Studies

Size: px

Start display at page:

Download "Reduced Order Modeling for Cooling -Battery/Electronics/Electric Machine Case Studies"

Cody Warner
5 years ago
Views:

1 Reduced Order Modeling for Cooling -Battery/Electronics/Electric Machine Case Studies Xiao Hu Scott Stanton ANSYS Inc. 1

2 Outline Motivation of using ROMs Introduction of LTI ROM LTI stands for linear and time invariant Advanced version of Foster network approach Introduction of SVD ROM SVD stands for singular value decomposition Coupling of ROMs with electrical circuit models 2

Can be computationally expensive for large models running

3 Motivation of Reduced Order Model (ROM) CFD as a general thermal analysis tool is accurate. Can be computationally expensive for large models running transient CFD analysis ROM can significantly reduce the model size and simulation time. 3

4 LTI ROM for Cooling 1. Create the CFD model 2. Generate step responses 3. Generate the LTI ROM Use Simplorer 4. Simulate inside Simplorer ICEPAK 4

5 Example : An IGBT Model The IGBT device consists of 4 IGBT s and 4 diodes. The device is cooled by cold plate below 5

6 Create the Step Responses in Icepak The number of CFD runs is equal to the number of inputs (8 runs) The runs were done automatically using Icepak 6

IGBT Device Step Response Step responses due to DIODE are shown below. Both small and large time scale exist. Self-heating is much larger than cross-heat.

7 IGBT Device Step Response Step responses due to DIODE are shown below. Both small and large time scale exist. Self-heating is much larger than cross-heat. The DIODE has strong impact on IGBT_A, but not much on IGBT_A.3 Only one of the eight sets of impulse responses are shown. There are 64 step responses in total. 7

8 Create the LTI ROM in Simplorer In simplorer ROM model is created based on the step responses. 8 inputs (power dissipation) and 8 outputs (temperature) 8

9 LTI ROM vs CFD Results To validate the LTI ROM results, same heat profiles are used in both LTI ROM and CFD and then results compared. Sample heat profile Similar profiles were givens as inputs to all IGBT s and Diodes 9

10 LTI ROM vs CFD Results 10

11 LTI ROM vs CFD Results 11

12 LTI ROM vs CFD Run-Time CFD runs in 2 hours LTI ROM runs in less than 2 seconds. 12

13 Example : A GM Battery Module The module consists of 16 cells. Hybrid mesh with a mesh count of 3 million ANSYS, Inc. September 25,

14 LTI ROM for GM Battery Module Heat Profile LTI ROM gives the same results as CFD. LTI ROM runs in less than 2 seconds while the CFD runs 2 hours on one single CPU. X. Hu, S. Lin, S. Stanton, W. Lian, A Foster Network Thermal Model for HEV/EV Battery Modeling, IEEE TRANSACTIONS ON INDUSTRY 14 APPLICATIONS, 2011 ANSYS, Inc. VOL. 47, NO. September 4, JULY/AUGUST 25, 2011 X. Hu, S. Lin, S. Stanton, W. Lian, A State Space Thermal Model for HEV/EV Battery Modeling", SAE

15 Icepak Model of the Cooling System Cold plate liquid cooling system : - Simplified cold plate without streams fluid design, - Glycol solution at 70 C, - Forced convection environment at 70 C. 15

16 Icepak-Simplorer LTI ROM Import Icepak model into Simplorer Computation and creation of the ROM from all the.out files generated by Icepak analysis New wizard helping on the setup and configuration of the LTI ROM creation Comparison of the transient response of the 3D model and the 1D LTI ROM 16

17 Meet the SVD ROM The LTI ROM can give temperature solution at user specified locations, but not temperature fields. SVD ROM technology allows for quick temperature field calculation in addition to average temperature calculation. VS S. Asgari, X. Hu, M. Tsuk, S. Kaushik, Application of POD plus LTI ROM to Battery Thermal Modeling: SISO Case, SAE congress. X. 17 Hu, S. Asgari, 2011 I. Yavuz, ANSYS, S. Inc. Stanton, C-C September Hsu, Z. Shi, 25, B. Wang, H-K Chu, A Transient Reduced Order Model for Battery Thermal Management Based on Singular Value Decomposition, ECCE.

18 Animation is a Trajectory 18

19 SVD ROM for Cooling 1. Create the CFD model 2. Generate step responses Cannot use Icepak Can only use FLUENT 3. Extract SVD ROM Use Simplorer 4. Simulate inside Simplorer ANSYS Fluent 5. Post-process results in Fluent ANSYS Fluent 19

20 SVD ROM : An IGBT Model Convective cooling channels used. Four IGBTs and four diodes generating heat. Icepak is used to create the mesh. Fluent model is exported from Icepak. Mesh size : 900 K. 20

21 SVD ROM vs. Fluent CFD To validate the SVD ROM results, same heat profiles are used in both SVD ROM and CFD and then results compared. Similar profiles were givens as inputs to all IGBT s and Diodes 21

22 SVD ROM vs. Fluent CFD CFD (15 sec) CFD (30 sec) CFD (45 sec) CFD (60 sec) SVD ROM (15 sec) SVD ROM (30 sec) SVD ROM (45 sec) SVD ROM (60 sec) While the two sets of results look very similar, the SVD ROM runs orders of magnitude faster! 22

23 Animation from SVD ROM Such an animation takes about 10 min to create! 23

24 SVD ROM Validation: GM 16 Cell Test Case CFD (200 sec) CFD (400 sec) CFD (600 sec) CFD (800 sec) SVD ROM (200 sec) SVD ROM (400 sec) SVD ROM (600 sec) SVD ROM (800 sec) X. 24 Hu, S. Asgari, 2011 I. Yavuz, ANSYS, S. Inc. Stanton, C-C September Hsu, Z. Shi, 25, B. Wang, H-K Chu, A Transient Reduced Order Model for Battery Thermal Management Based on Singular Value Decomposition, ECCE.

Temperature Distribution - Animation Temperature calculated from CFD. 5 hr simulation time with 6 CPUs. Temperature calculated from SVD ROM. 0.5 hr simulation time with 1 CPU. X. 25 Hu, S.

25 Temperature Distribution - Animation Temperature calculated from CFD. 5 hr simulation time with 6 CPUs. Temperature calculated from SVD ROM. 0.5 hr simulation time with 1 CPU. X. 25 Hu, S. Asgari, 2011 I. Yavuz, ANSYS, S. Inc. Stanton, C-C September Hsu, Z. Shi, 25, B. Wang, H-K Chu, A Transient Reduced Order Model for Battery Thermal Management Based on Singular Value Decomposition, ECCE.

26 SVD ROM Validation CFD (10 sec) CFD (20 sec) CFD (30 sec) CFD (40 sec) SVD ROM (10 sec) SVD ROM (20 sec) SVD ROM (30 sec) SVD ROM (40 sec) 26

27 SVD ROM Validation: Prius Motor CFD (200 sec) CFD (400 sec) CFD (600 sec) CFD (800 sec) SVD ROM (200 sec) SVD ROM (400 sec) SVD ROM (600 sec) SVD ROM (800 sec) 27 X. Hu, S. Lin, S. Stanton, A Transient Reduced Order Model for Electric Machines Based on Singular Value Decomposition, ITEC.

28 GM Battery Module ECM Coupled with ROMs ECM calculates heat source and sends it to the two ROMs. LTI ROM calculates average temperature and sends it to ECM. SVD ROM calculates temperature distribution. 28

29 ROMs/ECM Coupled Results LTI ROM calculates average temperature. SVD ROM calculates temperature field. Needs to be post-processed back in FLUENT. ECM calculates electrical performance. Average Cell Temperature Battery Voltage as a Function of Time 29

30 Complete Drive System Simulation 3-phase currents (left) and junction temperature of IGBTs and diodes (right). 30

31 Conclusion LTI ROM has shown to give similar results as CFD but runs orders of magnitude faster. SVD ROM helps calculate temperature field, which gives more information than LTI ROM. Both ROMs can be used in conjunction with electrical circuit models to have two-way coupled simulation. 31

32 Q&A Xiao Hu

Ben Zandi, Ph.D. TES International LLC

Advances in Modeling and Simulation of Vehicle Thermal Management Systems Variable-Fidelity, Multi-System Analysis Ben Zandi, Ph.D. TES International LLC www.tesint.com Outline The Need for Vehicle Thermal