# Integrated DC/DC Converter Topology Study for Fuel Cell Hybrid Vehicles with Two Energy Sources

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Improved Converter Topological Structure and Operating Principle

#### 2.1. Topological Structure

_{fc}, V

_{bat}, and u

_{o}, and the relationship between these values is as follows: V

_{fc}< V

_{bat}< u

_{o}.

_{1}and L

_{2}, and switched capacitor C

_{1}, and a negative temperature coefficient (NTC) thermistor R1 is used to inhibit the current surge in the capacitor at the moment of turn-on. In addition, the inductor L

_{2}, which, with the switch S5, is used again to form a charging loop from the main energy to auxiliary energy. Switch S4 controls the feedback circuit from the output port to the auxiliary energy. Switches S3 and S6 control the operation of the battery and the opening of the dual-source operating state.

#### 2.2. Operating Principle

- State 1:

- Mode 1:

_{2}is charged while inductor L

_{1}discharges to capacitor C

_{1}, and the load R

_{o}supplied by capacitor C

_{o}. It can be deduced that u

_{L}

_{1}= V

_{fc}− u

_{c}

_{1}− i

_{r}

_{1}R

_{1}, u

_{L}

_{2}= V

_{fc};

- Mode 2:

_{1}and L

_{2}are charged, the load R

_{o}is still supplied by capacitor C

_{o}. It can be deduced that u

_{L}

_{1}= u

_{L}

_{2}= V

_{fc};

- Mode 3:

_{1}is charged, while the inductor L

_{2}and capacitor C

_{1}discharge to the load R

_{o}together. It can be deduced that u

_{L}

_{1}= V

_{fc}, u

_{L}

_{2}= V

_{fc}+ u

_{c}

_{1}− u

_{o}.

- 2.
- State 2:

- 3.
- State 3:

- Mode 1:

_{2}is charged while inductor L

_{1}discharges to capacitor C

_{1}, and the load R

_{o}supplied by capacitor C

_{o}. It can be deduced that u

_{L}

_{1}= V

_{bat}− u

_{c}

_{1}− i

_{r}

_{1}R

_{1}, u

_{L}

_{2}= V

_{fc};

- Mode 2:

_{1}and L

_{2}are charged, the load R

_{o}is still supplied by capacitor C

_{o}. It can be deduced that u

_{L}

_{1}= V

_{bat}, u

_{L}

_{2}= V

_{fc};

- Mode 3:

_{1}is charged, while the inductor L

_{2}and capacitor C

_{1}discharge to the load R

_{o}together, it can be deduced that u

_{L}

_{1}= V

_{bat}, u

_{L}

_{2}= V

_{fc}+ u

_{c}

_{1}− u

_{o};

- Mode 4:

_{L}

_{1}= V

_{bat}− u

_{o}− i

_{r}

_{1}R

_{1}, u

_{L}

_{2}= V

_{fc}+ u

_{c}

_{1}− u

_{o}.

- 4.
- State 4:

- Mode 1:

_{2}can be charged and L

_{1}discharges to capacitor C

_{1}while the load resistance R

_{o}is supplied by capacitor C

_{o}. It can be deduced that u

_{L}

_{1}= V

_{fc}− u

_{c}

_{1}− i

_{r}

_{1}R

_{1}, u

_{L}

_{2}= V

_{fc};

- Mode 2:

_{2}discharges to the load R

_{o}, and capacitors C

_{1}is charged by the electric potential difference between the load and the battery, it can be deduced that u

_{L}

_{1}= V

_{fc}− u

_{o}, u

_{L}

_{2}= V

_{fc}− V

_{bat}, u

_{c}

_{1}= u

_{o}− V

_{bat};

- Mode 3:

_{1}is charged, while L

_{2}discharges to the battery port and load in series with the capacitor C

_{1}simultaneously. It can be deduced that u

_{L}

_{1}= V

_{fc}, u

_{L}

_{2}= V

_{fc}− V

_{bat};

- 5.
- State 5:

- Mode 1:

_{3}and the battery port are charged by the feedback-load. It can be deduced that u

_{L}

_{3}= u

_{o}− V

_{bat};

- Mode 2:

_{3}is renewed by diode D3. It can be deduced that u

_{L}

_{3}= V

_{bat}.

## 3. Steady-State Analysis

_{fc}, V

_{bat}, and u

_{o}, and the output voltage in different states is determined by the duty cycle. NTC thermistor resistance value decreases as the temperature rises due to instantaneous high current conduction, so it is assumed that the thermistor resistance value and voltage ripple of capacitors C

_{1}and C

_{o}can be neglected under steady-state conditions. If we consider the switching device as an ideal device, then, in a cycle, then there is an input-output relationship for each operating state as described below.

#### 3.1. Topology-Gain Analysis

#### 3.1.1. State 1

_{fc}, and the duty cycle of switch S1 and S2 is D. By applying the volt-second balance low over the inductors L

_{1}and L

_{2}, we have:

_{1}and the output voltage can be derived from Equations (1) and (2) as follows.

#### 3.1.2. State 2

_{bat}, and the duty cycle of switch S1 and S2 is D. By applying the volt-second balance low over the inductors L

_{1}and L

_{2}, we have:

_{1}and the output can be derived from Equations (5) and (6) as follows.

#### 3.1.3. State 3

_{fc}and V

_{bat}are the input voltages of converter circuit; meanwhile, d

_{1}and d

_{2}are the duty cycle of switches S1 and S2. The volt-second balance analysis of the inductor is divided into three cases: d

_{1}+ d

_{2}≥ 1, d

_{1}+ d

_{2}< 1 while d

_{1}> d

_{2}, and d

_{1}+ d

_{2}< 1 while d

_{1}< d

_{2}.

_{1}+ d

_{2}≥ 1,

_{1}and the output voltage can be derived from Equations (11) and (12) as follows.

_{1}+ d

_{2}< 1 and d

_{1}> d

_{2}, assume the time interval when the switch S1 is on and S2 is off, while the switching capacitor C

_{1}is charged by the battery, as a proportion of the cycle T is $\phi $. The modulation method should make $\phi $ increase as much as possible to ensure that the power of the battery is saved into the capacitor C

_{1}, and, because d

_{1}is greater than d

_{2}, so d

_{1}− d

_{2}≤ $\phi $ ≤ d

_{1}. Thus,

_{1}and the output can be derived from Equations (9) and (10) as follows.

_{1}+ d

_{2}< 1 and d

_{1}< d

_{2}, then 0 < $\phi $ ≤ d

_{1}. The volt-second balance analysis of the inductors L

_{1}and L

_{2}is the same as Equations (9) and (10) under this condition, and the voltage across capacitor C

_{1}and the output are the same as Equations (11) and (12). As $\phi $ = 0, battery supplies power to load directly, and the volt-second balance analysis is shown below.

_{1}and the output can be derived from Equations (13) and (14) as follows.

_{1}+ d

_{2}≥ 1, Equation (12) is multiplied by the output current I

_{o}and the respective input power of the fuel cell and the battery can be known, which will be explained later.

#### 3.1.4. State 4

_{fc}, while the output is V

_{bat}and u

_{o}, and the duty cycles of switches S1, S2, and S5 are d

_{1}, d

_{2}, and d

_{5}, of which S1 and S5 are in complementary conduction such that d

_{1}+ d

_{5}= 1. When S5 is on, the capacitor C

_{1}and the load R

_{o}will form a parallel connection, the battery discharges to the capacitor and load, then u

_{o}= u

_{c}

_{1}+ V

_{bat}, by applying the volt-second balance low over the inductors L

_{1}and L

_{2}, we have:

_{1}and the output of the battery and load port can be derived from Equations (21) and (22) as follows.

#### 3.1.5. State 5

_{o}, the battery’s energy-storage port voltage is V

_{bat}, and the duty cycle of switch S4 is d

_{4}, by applying the volt-second balance low over the inductors L

_{1}and L

_{2}, we have:

#### 3.2. Switching Capacitor Charge/Discharge Characteristics Analysis

_{ds}is the on-resistance of switch S1, V

_{F}is the on-voltage drop of diode, the inductor and capacitor internal resistance is much smaller than the equivalent load R

_{o}, and R

_{1}is the NTC thermistor. If the inductor and capacitor internal resistance is ignored, the voltage ripple coefficient of the switching capacitor is analyzed as follows.

_{1}in Figure 3 is $\Delta {i}_{L1}^{+}$ or $\Delta {i}_{L1}^{-}$, as follows:

_{1}is zero, the starting current approach to the initial current of inductor discharging ${I}_{fcint}$ at t tends to be zero.

#### 3.3. Voltage and Current Analysis

- The average current of inductors is equal at state 1 and state 2, and the sum of the two is equal to the input current I
_{in}. The system does not carry out power distribution at this time, thus:$${I}_{L1}={I}_{L2}=\frac{1}{2}{I}_{in}=\frac{1}{2}\frac{2}{(1-D)}{I}_{o}$$_{in}can be the input current of the fuel cell or battery, and D is the duty cycle of switches S1 and S2. - Similarly, I
_{L}_{1}and I_{L}_{2}are equal to the battery input current I_{b}and fuel cell input current I_{fc}, respectively, at state 3, so:$${I}_{L1}={I}_{b}=\frac{1}{(1-{d}_{2})}{I}_{o}$$$${I}_{L2}={I}_{fc}=\frac{1}{(1-{d}_{1})}{I}_{o}$$$${I}_{L2}={I}_{fc}=\frac{\phi}{(1-{d}_{1})(1-{d}_{2})}{I}_{o}$$ - As mentioned before, the average current I
_{L}_{1}and I_{L}_{2}is equal to the fuel cell input current I_{fc}_{1}and I_{fc}_{2}at state 4, so:$${I}_{L1}={I}_{fc1}=\frac{1}{(1-{d}_{2}){d}_{5}}{I}_{o}$$$${I}_{L2}={I}_{fc2}=\frac{1}{{d}_{5}}{I}_{b}$$ - When braking feedback, the average current I
_{L}_{3}of inductor I_{L}_{3}is equal to the output current I_{b}, thus we can obtain:$${I}_{L3}={I}_{b}=\frac{1}{{d}_{4}}{I}_{Load}$$_{Load}is the braking feedback current.

## 4. Topology Dynamic Modeling and Controller Solutions

_{1}and L

_{2}and the voltage across the capacitors C

_{1}and C

_{o}be the state variables ${\widehat{x}}_{1,2,3,4}$. Furthermore, let the duty cycle d

_{1}and d

_{2}be the control variables ${\widehat{u}}_{1,2,3,4}$. For state 5, set the current of the inductor L

_{3}and the voltage of the capacitor C

_{b}at the battery end as state variables ${\widehat{x}}_{5}$, and the duty cycle d

_{4}as the control variables ${\widehat{u}}_{5}$.

_{o}and R

_{b}be the load and battery port equivalent resistance in known conditions. Finally, five different state space averaging models can be derived as follows.

_{1}= d

_{2}= D in this state to control the output voltage U

_{o}, its state-space expression is:

_{1}and d

_{2}control the output voltage U

_{o}and Capacitance voltage U

_{c}

_{1}. Its state-space expression is:

_{1}and d

_{2}control the output voltage U

_{o}and Capacitance voltage U

_{c}

_{1}and then the battery port voltage V

_{bat}will be uniquely determined by the former. Its state-space expression is:

_{fc}proportional to P

_{bat}according to the energy management strategy. According to Equations (11), (12), (35) and (36), this proportional relationship is expressed as P

_{fc}:P

_{bat}= (U

_{o}−U

_{c}

_{1}):U

_{c}

_{1}. Therefore, the control volume also needs to control the relationship between the magnitude of the load output and the capacitor C1 voltage to regulate the proportion of power input.

_{o}−U

_{c}

_{1}):U

_{c}

_{1}. Then, Figure 6b shows the effect of changing the ratio of the two energy power inputs with the desired voltage ratio. The control principle of state 4 does not differ from state 3, so it is not repeated.

## 5. Comparative Analysis of Related Converter Topologies

## 6. Simulation Experiments and Results Analysis

_{1}and L

_{2}, when the input is fuel cell. While Figure 8c,d shows the same items when the input is the battery.

_{1}and L

_{2}at this time.

_{1}and L

_{2}and battery port at this time. The battery port is kept at a constant voltage in this operating mode.

_{3}current and the charging and discharging waveform.

## 7. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

- Gao, Z.; Li, X.; Liu, Z.; Rao, J. Research status and development trend of hydrogen fuel cell vehicles. Mater. Rep.
**2022**, 36, 74–81. [Google Scholar] [CrossRef] - Guo, N.; Zhang, X.; Zou, Y.; Guo, L.; Du, G. Real-time predictive energy management of plug-in hybrid electric vehicles for coordination of fuel economy and battery degradation. Energy
**2021**, 214, 119070. [Google Scholar] [CrossRef] - Feng, Y. Toyota Mirai hydrogen fuel cell vehicle analysis. Automot. Repair Maint.
**2020**, 8, 71–73. [Google Scholar] - Babaei, E.; Sakhavati, S. An overview of different topologies of multi-port dc/dc converters for dc renewable energy source applications. In Proceedings of the 2016 13th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, Chiang Mai, Thailand, 28 June–1 July 2016. [Google Scholar] [CrossRef]
- Vermulst, B.J.; Duarte, J.L.; Lomonova, E.A.; Wijnands, K.G. Scalable multi-port active-bridge converters: Modelling and optimised control. IET Power Electron.
**2017**, 10, 80–91. [Google Scholar] [CrossRef] - Song, S.; Li, W.; Ni, K.; Xu, H.; Hu, Y.; Si, J. Modular Multi-Port Ultra-High Power Level Power Converter Integrated with Energy Storage for High Voltage Direct Current (HVDC) Transmission. Energies
**2018**, 11, 2711. [Google Scholar] [CrossRef] [Green Version] - Wang, C.; Li, W.; Wang, Y.; Han, F.; Meng, Z.; Li, G. An Isolated Three-Port Bidirectional DC-DC Converter with Enlarged ZVS Region for HESS Applications in DC Microgrids. Energies
**2017**, 10, 446. [Google Scholar] [CrossRef] [Green Version] - Li, W.; Wang, Y.; Han, F.; Chen, B. An isolated three-port bidirectional LCLC multiresonant DC converter. Trans. China Electrotech. Soc.
**2018**, 33, 3231–3244. [Google Scholar] [CrossRef] - Peng, Y. Study of Input-Output Relationships of Four-Port DC Converters. Chin. LABAT Man
**2018**, 55, 18–22. [Google Scholar] [CrossRef] - Wang, H.; Li, H.; Liu, J. A Wide-Range Soft-Switching High-Gain Bidirectional Multi-Port Converter. Power Electron.
**2019**, 53, 74–77+82. [Google Scholar] - Akar, F.; Tavlasoglu, Y.; Ugur, E.; Vural, B.; Aksoy, I. A Bidirectional Nonisolated Multi-Input DC–DC Converter for Hybrid Energy Storage Systems in Electric Vehicles. IEEE Trans. Veh. Technol.
**2016**, 65, 7944–7955. [Google Scholar] [CrossRef] - Wang, H.; Tian, Q.; Shen, Y.; Yu, T. Non-isolated three-port converter with wide operating range and low EMI characteristics. Sci. Technol. Vis.
**2021**, 3, 34–39. [Google Scholar] [CrossRef] - Pourjafar, S.; Shayeghi, H.; Sedaghati, F.; Seyedshenava, S.; Blaabjerg, F. A bidirectional multiport DC-DC converter applied for energy storage system with hybrid energy sources. Int. J. Circ. Theor. Appl.
**2021**, 49, 2453–2478. [Google Scholar] [CrossRef] - Shayeghi, H.; Pourjafar, S.; Hashemzadeh, S.M. A Switching Capacitor based Multi-Port Bidirectional DC-DC Converter. IET Power Electron.
**2021**, 14, 1622–1636. [Google Scholar] [CrossRef] - Yi, W.; Ma, H.; Peng, S.; Liu, D.; Ali, Z.M.; Dampage, U.; Hajjiah, A. Analysis and implementation of multi-port bidirectional converter for hybrid energy systems. Energy Rep.
**2022**, 8, 1538–1549. [Google Scholar] [CrossRef] - Suresh, K.; Bharatiraja, C.; Chellammal, N.; Tariq, M.; Chakrabortty, R.K.; Ryan, M.J.; Alamri, B. A Multifunctional Non-Isolated Dual Input-Dual Output Converter for Electric Vehicle Applications. IEEE Access
**2021**, 9, 64445–64460. [Google Scholar] [CrossRef] - Zhang, J.; Wu, H.; Huang, J.; Xing, Y.; Ma, X. Research on Multi-port Bidirectional Buck-Boost Converter. Power Electron.
**2021**, 55, 129–135. [Google Scholar] [CrossRef] - Jiang, L.; Fan, J.; Zhang, W.; He, D.; Liao, Z. Simulation Study of Three-Port DC/DC Converters. China Comput. Commun.
**2021**, 33, 1–4. [Google Scholar] - Shao, Z. Analysis of a non-transformer isolated three-port converter with single input and dual output operation mode. J. Xuchang Univ.
**2019**, 38, 131–133. [Google Scholar] - Moradisizkoohi, H.; Elsayad, N.; Mohammed, O.A. An Integrated Interleaved Ultrahigh Step-Up DC–DC Converter Using Dual Cross-Coupled Inductors With Built-In Input Current Balancing for Electric Vehicles. IEEE J. Emerg. Sel. Top. Power Electron.
**2019**, 8, 644–657. [Google Scholar] [CrossRef] - Kumar, A.; Sensarma, P. Ripple-Free Input Current High Voltage Gain DC-DC Converters With Coupled Inductors. IEEE Trans. Power Electron.
**2019**, 34, 3418–3428. [Google Scholar] [CrossRef] - Faraji, R.; Farzanehfard, H. Soft-Switched Nonisolated High Step-Up Three-Port DC–DC Converter for Hybrid Energy Systems. IEEE Trans. Power Electron.
**2018**, 33, 10101–10111. [Google Scholar] [CrossRef] - Kardan, F.; Alizadeh, R.; Banaei, M.R. A novel step-up multi-input DC-DC converter for hybrid electric vehicles application. IEEE Trans. Power Electron.
**2017**, 32, 3549–3561. [Google Scholar] [CrossRef] - Kardan, F.; Alizadeh, R.; Banaei, M. A New Three Input DC/DC Converter for Hybrid PV/FC/Battery Applications. IEEE J. Emerg. Sel. Top. Power Electron.
**2017**, 5, 1771–1778. [Google Scholar] [CrossRef] - Jalilzadeh, T.; Rostami, N.; Babaei, E.; Hosseini, S.H. Bidirectional Multi-Port DC-DC Converter with Low Voltage Stress on Switches and Diodes. IET Power Electron.
**2020**, 13, 1593–1604. [Google Scholar] [CrossRef] - Liu, J.; Hu, R.; Zeng, J. Non-isolated three-port converter with high gain. Trans. China Electrotech. Soc.
**2019**, 34, 10. [Google Scholar] [CrossRef] - Ma, S.; Pan, T. Switched-Capacitor Based Three-Port DC-DC Converters. J. Power Supply
**2015**, 13, 48–55. [Google Scholar] [CrossRef] - Wang, H.; Chen, Y.; Zeng, Q.; Li, S.; Zhu, B. A Multi-Condition High Gain Multi-Port DC/DC Converter. Proc. CSEE
**2019**, 39, 2155–2166. [Google Scholar] [CrossRef] - Fares, A.M.; Klumpner, C.; Sumner, M. A Novel Multiport DC-DC Converter for Enhancing the Design and Performance of Battery—Supercapacitor Hybrid Energy Storage Systems for Unmanned Aerial Vehicles. Appl. Sci.
**2022**, 12, 2767. [Google Scholar] [CrossRef] - Santosh Kumar Reddy, P.; Obulesu, Y. Design and Development of a New Transformerless Multi-port DC-DC Boost Converter. J. Electr. Eng. Technol.
**2022**, 14, 23–38. [Google Scholar] [CrossRef] - Suntiom, T.; Messo, T.; Puukko, J. Power Electronic Converters—Dynamics and Control in Conventional and Renewable Energy Applications; John Wiley & Sons: Weinheim, Germany, 2017. [Google Scholar] [CrossRef]
- Venkataramana, S. Small Signal Modeling of Non-Isolated High Gain DC-DC converter. In Proceedings of the 2020 International Conference for Emerging Technology (INCET), Belgaum, India, 5–7 June 2020. [Google Scholar] [CrossRef]

**Figure 2.**Equivalent circuits of five different operating states: (

**a**) State 1; (

**b**) State 2; (

**c**) State 3; (

**d**) State 4; (

**e**) State 5.

**Figure 3.**The equivalent circuit for capacitor charging and discharging: (

**a**) charging circuit; (

**b**) discharging circuit.

**Figure 4.**System control block diagram: (

**a**) control block diagram of state 1 to 4 (d

_{1}= d

_{2}at state 1 and 2, d

_{1}≠ d

_{2}at state 3 and 4); (

**b**) control block diagram of state 5.

**Figure 5.**The effect of controller under working state 1 and 2: (

**a**) output voltage under load switching conditions; (

**b**) output voltage following the desired value schematic.

**Figure 6.**The effect of controller under working state 3: (

**a**) output voltage under variable voltage scaling conditions; (

**b**) result of proportional change in power input.

**Figure 8.**The simulation results of state 1 and 2: (

**a**) the voltages of output and capacitor in state 1; (

**b**) the average currents and their waveforms of inductors L

_{1}and L

_{2}in state 1; (

**c**) the voltages of output and capacitor in state 2; (

**d**) the average currents and their waveforms of inductors L

_{1}and L

_{2}in state 2.

**Figure 9.**The simulation results of state 3: (

**a**) the voltages of output and capacitor in state 3; (

**b**) the average currents and their waveforms of inductors L

_{1}and L

_{2}in state 3.

**Figure 10.**The simulation results of charging work: (

**a**) the load and battery output voltage in state 4; (

**b**) the average currents and waveforms in state 4.

**Figure 11.**The simulation results of the operation of the load braking energy feedback: (

**a**) the battery charging voltage in state 5; (

**b**) the inductance current in state 5.

**Figure 12.**Capacitor charging spike current waveform: (

**a**) current without thermistor in series; (

**b**) current with thermistor in series.

**Figure 13.**The output during state switching and its sequence: (

**a**) voltage waveform of operating state switching; (

**b**) current waveform of operating state switching; (

**c**) switching sequence of operating states.

Study Number | Number of Switches | Number of Inductors | Number of Capacitors | Boost Gain | Number of Applicable States | Bi-Directional Function | Power Distribution Function | Port Independently |
---|---|---|---|---|---|---|---|---|

[11] | 4 | 2 | 1 | $\frac{{d}_{2}}{1-{d}_{1}}$ | 3 | √ | √ | × |

[14] | 3 | 2 | 3 | $\frac{1+D}{1-D}{V}_{L}+{V}_{2}$ | 2 | √ | × | × |

[16] | 3 | 2 | 3 | $\frac{1}{1-{d}_{1}}$ | 5 | √ | × | √ |

[24] | 4 | 2 | 1 | $\frac{\left(1+{D}^{2}-d\right)}{{\left(1-D\right)}^{2}}$ | 3 | × | × | × |

[27] | 3 | 3 | 3 | $1+\frac{1}{1-D}$ | 5 | × | × | √ |

[28] | 5 | 2 | 2 | $\frac{2}{1-D}$ | 4 | × | √ | √ |

Proposed | 6 | 3 | 2 | $\frac{2}{1-D}$ | 5 | √ | √ | √ |

Parameters | Values | Parameters | Values |
---|---|---|---|

Fuel cell voltage V_{fc} | 120 to 160 V | Inductor L_{1} | 1.28 × 10^{−3}H |

Battery voltage V_{bat} | 168 V | Inductor L_{2} | 1.28 × 10^{−3}H |

Load rated voltage u_{o} | 650 V | Inductor L_{3} | 0.747 × 10^{−3}H |

Load port current I_{o} | 1.5 A | Capacitor C_{1} | 4.8 × 10^{−6}F |

Battery port resistance R_{bat} | 25 Ω | Capacitor C_{o} | 9.192 × 10^{−6}F |

Load port resistance R_{o} | 422 Ω | Frequency | 100 kHz |

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## Share and Cite

**MDPI and ACS Style**

Xie, W.; Luo, W.; Qin, Y.
Integrated DC/DC Converter Topology Study for Fuel Cell Hybrid Vehicles with Two Energy Sources. *World Electr. Veh. J.* **2023**, *14*, 9.
https://doi.org/10.3390/wevj14010009

**AMA Style**

Xie W, Luo W, Qin Y.
Integrated DC/DC Converter Topology Study for Fuel Cell Hybrid Vehicles with Two Energy Sources. *World Electric Vehicle Journal*. 2023; 14(1):9.
https://doi.org/10.3390/wevj14010009

**Chicago/Turabian Style**

Xie, Weijin, Wenguang Luo, and Yongxin Qin.
2023. "Integrated DC/DC Converter Topology Study for Fuel Cell Hybrid Vehicles with Two Energy Sources" *World Electric Vehicle Journal* 14, no. 1: 9.
https://doi.org/10.3390/wevj14010009