# Research on Multi-Mode Braking Energy Recovery Control Strategy for Battery Electric Vehicles
## 4 Co-Simulation and Analysis of Results
### Cruise and Matlab/Simulink Co-Simulation Analysis  
#### 4.2.1 Cyclic Condition Simulation  
NEDC (New European Driving Cycle) and CLTC-P (China Light-duty Vehicle Test Cycle-Passenger) were simulated test conditions. The NEDC cycle runs for 1180 s, consisting of four urban cycles and one suburban cycle, while the CLTC-P cycle consists of three intervals of low, medium, and high speeds, with a cycle running time of 1800 s. Figure 13 shows the speed following curves of the NEDC and CLTC-P conditions, respectively, showing that the established EV models can follow the desired speeds well, and follow the desired speed for the two different working conditions. (1) NEDC cycle conditions  
The initial SOC of the HV battery is set to 80%, and the end SOC is set to 10%. The comparison of the range under NEDC conditions is shown in Figure 14. From the figure, it can be seen that the vehicle's range is lowest when the power recovery control strategy is not added, which is 233 km; the range under the single-mode brake energy recovery control strategy is significantly increased, with a range of 325 km and a range contribution rate of 39.5%; after adding the multi-mode brake energy recovery control strategy proposed \begin{table}
\begin{tabular}{c c} \hline
**Name** & **Value** \\ \hline Rated voltage & 288 V \\ Total capacity & 150 Ah \\ Total energy & 43.2 kW \\ Unit voltage & 3.2 V \\ Unit capacity & 30 Ah \\ Battery Type & Lithium iron phosphate battery \\ \hline \end{tabular}
\end{table} 
Table 7: Basic parameters of the battery. Figure 13: Vehicle speed the following curve for two working conditions: (**a**) NEDC speed tracking curve for operating conditions; (**b**) CLTC-P operating speed tracking curve plot. in this paper, the range is significantly increased, with a range of 347.5 km, and the range mileage contribution rate is 49.1%. Compared with the single-mode brake energy recovery control strategy, the range contribution rate is increased by 9.6%, the range is increased by 22.5 km, and the range is increased by 114.5 km compared with the no-brake energy recovery control strategy. Figure 15 shows the SOC value curve change under NEDC conditions, from which it can be seen that the battery electric vehicle can effectively improve the vehicle range after adding the brake energy recovery control strategy. Before the start of the cycle, the initial value of the HV battery SOC is 80%. After the end of the cycle, it can be seen that the SOC value under the multi-mode brake energy recovery control strategy is 77.76%, which is higher than the 77.68% under the single-mode brake energy recovery control strategy and is significantly higher than the 76.88% of the no-brake energy recovery control strategy. Figure 14: NEDC operating range comparison chart. Figure 15: SOC change curve of NEDC working condition. Figure 16 show the energy recovery and consumption graph under NEDC conditions. It can be seen that the single-mode brake energy recovery control strategy recovers 1918 kJ of energy and outputs 7197 kJ of energy, with a brake energy recovery rate of 26.6%. In contrast, the multi-mode brake energy recovery control strategy recovers 2299 kJ of energy and outputs 7526 kJ, with a brake energy recovery rate of 30.6%. However, the output of energy from the multi-mode brake energy recovery control strategy is slightly higher than that of the single-mode control strategy. Although the output energy of the multi-mode brake energy recovery control strategy is somewhat higher than that of the single-mode brake energy recovery control strategy, the brake energy recovery rate is increased by 4% compared with the single-mode control strategy. (2) CLTC-P cycle condition  
Again, the initial SOC of the HV battery is set to 80%, the end SOC is set to 10%, and the depth of discharge is 80%.