# A Comparison of Non-Isolated High-Gain Three-Port Converters for Hybrid Energy Storage Systems

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Limitations of the Direct Parallel Connection

#### 2.1. Effects of the Waveform Shape in the Thermal Efforts

#### 2.2. Prototype and Experimental Setup

## 3. The Full Bridge Converter

## 4. Series Connection of the Storage Systems

## 5. Analysis of the Series-Parallel Connection

- The UM is a unipolar DC device, and the terminal of negative polarity is attached to the center point of the battery leg. Thus, it can be deduced from (30) that ${D}_{{3}_{D}}$ is greater than ${D}_{{1}_{D}}$ in steady state.
- The switching pulses of all the switches are synchronized at the same frequency, ${f}_{S}$.
- The ripple values of the current through both inductors and of the voltage at the capacitor, are relatively smaller than the respective average values.
- Each leg at the converter operates in a complementary scheme, i.e., the pulse signals for the lower switches are the logical inverted pulses of the upper ones. It is also assumed that a dead time is implemented in the switching scheme, aiming to avoid cross-conduction, and that its effect in the overall performance can be neglected.
- The initial conditions assume a positive value for ${i}_{EB}$, i.e., the battery is being discharged towards the DC link.
- Finally, it is also considered a positive value for ${i}_{UM}$, i.e., the UM is also being discharged. However, to increase the generality of the analysis, in a later stage, the case of negative ${i}_{UM}$ will also be considered.

#### 5.1. Mode I. S_{2} and S_{4} Turned On

#### 5.2. Mode II. S_{2} and S_{3} Turned On

#### 5.3. Mode III. S_{1} and S_{3} Turned On

#### 5.4. Mode IV. S_{1} and S_{4} Turned On

## 6. SPC Steady State Analysis

## 7. Losses Comparison and Effects in the Efficiency

## 8. SPC Scheme in Hybrid Storage Systems Applications

## 9. Stability of the SPC Scheme

## 10. Conclusions and Future Developments

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## Abbreviations

DPC | Direct Parallel Connection |

EB | Electrochemical Battery |

ESS | Energy Storage System |

FBC | Full-Bridge Converter |

${K}_{f}$ | Form Factor |

HSS | Hybrid Storage Systems |

PEC | Power Electronic Converter |

PECG | Grid-tied Power Electronic Converter |

PECL | Power Electronic Converter at Load/Generator |

SC | Series Connection |

SPC | Series-Parallel Connection |

UM | Ultracapacitor Module |

## References

- Thounthong, P.; Rael, S. The benefits of hybridization. IEEE Ind. Electron. Mag.
**2009**, 3, 25–37. [Google Scholar] [CrossRef] - Jayasinghe, S.D.G.; Vilathgamuwa, D.M. Flying Supercapacitors as Power Smoothing Elements in Wind Generation. IEEE Trans. Ind. Electron.
**2013**, 60, 2909–2918. [Google Scholar] [CrossRef] - Wu, H.; Xu, P.; Hu, H.; Zhou, Z.; Xing, Y. Multiport Converters Based on Integration of Full-Bridge and Bidirectional DC-DC Topologies for Renewable Generation Systems. IEEE Trans. Ind. Electron.
**2014**, 61, 856–869. [Google Scholar] [CrossRef] - Abeywardana, D.B.W.; Hredzak, B.; Agelidis, V.G. Single-Phase Grid-Connected LiFePO/Battery-Supercapacitor Hybrid Energy Storage System With Interleaved Boost Inverter. IEEE Trans. Power Electron.
**2015**, 30, 5591–5604. [Google Scholar] [CrossRef] - Pereirinha, P.G.; Trovao, J.P. Multiple Energy Sources Hybridization, The Future of Electric Vehicles? In New Generation of Electric Vehicles; Stevic, Z., Ed.; InTech: London, UK, 2012. [Google Scholar]
- Lu, S.; Corzine, K.A.; Ferdowsi, M. A Unique Ultracapacitor Direct Integration Scheme in Multilevel Motor Drives for Large Vehicle Propulsion. IEEE Trans. Veh. Technol.
**2007**, 56, 1506–1515. [Google Scholar] [CrossRef] - Abdel-baqi, O.; Nasiri, A.; Miller, P. Dynamic Performance Improvement and Peak Power Limiting Using Ultracapacitor Storage System for Hydraulic Mining Shovels. IEEE Trans. Ind. Electron.
**2015**, 62, 3173–3181. [Google Scholar] [CrossRef] - Liu, J.; Zhang, L. Strategy Design of Hybrid Energy Storage System for Smoothing Wind Power Fluctuations. Energies
**2016**, 9, 991. [Google Scholar] [CrossRef] - Miñambres Marcos, V.M.; Guerrero-Martínez, M.A.; Barrero-González, F.; Milanés-Montero, M.I. A Grid Connected Photovoltaic Inverter with Battery-Supercapacitor Hybrid Energy Storage. Sensors
**2017**, 17, 1856. [Google Scholar] [CrossRef] [PubMed] - Jayasinghe, S.D.G.; Vilathgamuwa, D.M.; Madawala, U.K. A direct integration scheme for battery-supercapacitor hybrid energy storage systems with the use of grid side inverter. In Proceedings of the 2011 Twenty-Sixth Annual IEEE Applied Power Electronics Conference and Exposition (APEC), Fort Worth, TX, USA, 6–11 March 2011; pp. 1388–1393. [Google Scholar]
- Guidi, G.; Undeland, T.M.; Hori, Y. An Optimized Converter for Battery-Supercapacitor Interface. In Proceedings of the 2007 IEEE Power Electronics Specialists Conference, Orlando, FL, USA, 17–21 June 2007; pp. 2976–2981. [Google Scholar]
- Barrade, P.; Delalay, S.; Rufer, A. Direct Connection of Supercapacitors to Photovoltaic Panels With On-Off Maximum Power Point Tracking. IEEE Trans. Sustain. Energy
**2012**, 3, 283–294. [Google Scholar] [CrossRef] - Yoo, H.; Sul, S.K.; Park, Y.; Jeong, J. System Integration and Power-Flow Management for a Series Hybrid Electric Vehicle Using Supercapacitors and Batteries. IEEE Trans. Ind. Appl.
**2008**, 44, 108–114. [Google Scholar] [CrossRef] - Oriti, G.; Julian, A.L.; Anglani, N.; Hernandez, G.D. Novel Hybrid Energy Storage Control for a Single Phase Energy Management System in a Remote Islanded Microgrid. In Proceedings of the 2017 IEEE Energy Conversion Congress and Exposition (ECCE), Cincinnati, OH, USA, 1–5 October 2017; pp. 1552–1559. [Google Scholar]
- Mohan, N.; Undeland, T.M.; Robbins, W.P. Power Electronics: Converters, Applications, and Design, 3rd ed.; Wiley and Sons: Hoboken, NJ, USA, 2003. [Google Scholar]
- Yamamoto, K.; Imakiire, A.; Lin, R.; Iimori, K. Comparison of configurations of voltage boosters in PWM inverter with voltage boosters with regenerating circuit augmented by electric double-layer capacitor. In Proceedings of the 2009 International Conference on Electrical Machines and Systems, Tokyo, Japan, 15–18 November 2009; pp. 1–6. [Google Scholar]
- Tucker, J. Understanding Output Voltage Limitations of DC/DC Buck Converters; Texas Instruments Incorporated: Dallas, TX, USA, 2008. [Google Scholar]
- Song, J.; Kwasinski, A. Analysis of the effects of duty cycle constraints in multiple-input converters for photovoltaic applications. In Proceedings of the INTELEC 2009—31st International Telecommunications Energy Conference, Incheon, Korea, 18–22 October 2009; pp. 1–5. [Google Scholar]
- Dusmez, S.; Hasanzadeh, A.; Khaligh, A. Comparative Analysis of Bidirectional Three-Level DC-DC Converter for Automotive Applications. IEEE Trans. Ind. Electron.
**2015**, 62, 3305–3315. [Google Scholar] [CrossRef] - Grbovic, P.J.; Delarue, P.; Moigne, P.L.; Bartholomeus, P. A Bidirectional Three-Level DC-DC Converter for the Ultracapacitor Applications. IEEE Trans. Ind. Electron.
**2010**, 57, 3415–3430. [Google Scholar] [CrossRef] - Azongha, S.; Liu, L.; Li, H. Utilizing ultra-capacitor energy storage in motor drives with cascaded multilevel inverters. In Proceedings of the 2008 34th Annual Conference of IEEE Industrial Electronics, Orlando, FL, USA, 10–13 November 2008; pp. 2253–2258. [Google Scholar]
- Rufer, A.; Barrade, P. A supercapacitor-based energy-storage system for elevators with soft commutated interface. IEEE Trans. Ind. Appl.
**2002**, 38, 1151–1159. [Google Scholar] [CrossRef] - Ding, Z.; Yang, C.; Zhang, Z.; Wang, C.; Xie, S. A Novel Soft-Switching Multiport Bidirectional DC-DC Converter for Hybrid Energy Storage System. IEEE Trans. Power Electron.
**2014**, 29, 1595–1609. [Google Scholar] [CrossRef] - Zhou, H.; Duong, T.; Sing, S.T.; Khambadkone, A.M. Interleaved bi-directional Dual Active Bridge DC-DC converter for interfacing ultracapacitor in micro-grid application. In Proceedings of the 2010 IEEE International Symposium on Industrial Electronics, Bari, Italy, 4–7 July 2010; pp. 2229–2234. [Google Scholar]
- Tao, H.; Kotsopoulos, A.; Duarte, J.L.; Hendrix, M.A.M. Family of multiport bidirectional DC-DC converters. In IEE Proceedings—Electric Power Applications; IET: Stevenage, UK, 2006; Volume 153, pp. 451–458. [Google Scholar]
- Georgious, R.; Garcia, J.; Navarro, A.; Saeed, S.; Garcia, P. Series-Parallel Connection of Low-Voltage sources for integration of galvanically isolated Energy Storage Systems. In Proceedings of the 2016 IEEE Applied Power Electronics Conference and Exposition (APEC), Long Beach, CA, USA, 20–24 March 2016; pp. 3508–3513. [Google Scholar]
- Garcia, J.; Georgious, R.; Garcia, P.; Navarro-Rodriguez, A. Non-isolated high-gain three-port converter for hybrid storage systems. In Proceedings of the 2016 IEEE Energy Conversion Congress and Exposition (ECCE), Milwaukee, WI, USA, 18–22 September 2016; pp. 1–8. [Google Scholar]
- Tofoli, F.L.; de Castro Pereira, D.; de Paula, W.J.; de Sousa Oliveira Júnior, D. Survey on non-isolated high-voltage step-up dc-dc topologies based on the boost converter. IET Power Electron.
**2015**, 8, 2044–2057. [Google Scholar] [CrossRef] - Zhang, N.; Sutanto, D.; Muttaqi, K.M.; Zhang, B.; Qiu, D. High-voltage-gain quadratic boost converter with voltage multiplier. IET Power Electron.
**2015**, 8, 2511–2519. [Google Scholar] [CrossRef] - Hu, X.; Gong, C. A High Voltage Gain DC-DC Converter Integrating Coupled-Inductor and Diode-Capacitor Techniques. IEEE Trans. Power Electron.
**2014**, 29, 789–800. [Google Scholar] - Silveira, G.C.; Tofoli, F.L.; Bezerra, L.D.S.; Torrico-Bascopé, R.P. A Nonisolated DC-DC Boost Converter With High Voltage Gain and Balanced Output Voltage. IEEE Trans. Ind. Electron.
**2014**, 61, 6739–6746. [Google Scholar] [CrossRef] - Langarica-Córdoba, D.; Diaz-Saldierna, L.H.; Leyva-Ramos, J. Fuel-cell energy processing using a quadratic boost converter for high conversion ratios. In Proceedings of the 2015 IEEE 6th International Symposium on Power Electronics for Distributed Generation Systems (PEDG), Aachen, Germany, 22–25 June 2015; pp. 1–7. [Google Scholar]
- Georgiev, A.; Papanchev, T.; Nikolov, N. Reliability assessment of power semiconductor devices. In Proceedings of the 2016 19th International Symposium on Electrical Apparatus and Technologies (SIELA), Bourgas, Bulgaria, 29 May–1 June 2016; pp. 1–4. [Google Scholar]
- Wang, C.S.; Li, W.; Wang, Y.F.; Han, F.Q.; Meng, Z.; Li, G.D. 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] - Tan, X.; Li, Q.; Wang, H. Advances and trends of energy storage technology in Microgrid. Int. J. Electr. Power Energy Syst.
**2013**, 44, 179–191. [Google Scholar] [CrossRef]

**Figure 2.**Non-isolated topologies considered for the HSS: (

**a**) Direct Parallel Connection (DPC); (

**b**) Full-Bridge Connection (FBC); (

**c**) Series Connection (SC); and (

**d**) Series-Parallel Connection (SPC).

**Figure 3.**Experimental setup that can be configured as Parallel Connection (PC), Full Bridge Converter (FBC), Series Connection (SC) or Series-Parallel Connection (SPC).

**Figure 4.**Experimental waveforms of the DPC scheme. Steady states: (

**a**) ${i}_{EB}$ = 10 A, ${i}_{UM}$ = 10 A; and (

**b**) ${i}_{EB}$ = 10 A, ${i}_{UM}$ steps from 1 A to −1 A.

**Figure 5.**Switching modes in the SPC for the pulse scheme considered: (

**a**) ${D}_{{3}_{D}}$ is greater than ${D}_{{1}_{D}}$; and (

**b**) ${D}_{{3}_{D}}$ is smaller than ${D}_{{1}_{D}}$ (only in transients).

**Figure 6.**Switching modes in the SPC scheme: (

**a**) Mode I; (

**b**) Mode II; (

**c**) Mode III; and (

**d**) Mode IV.

**Figure 7.**Theoretical waveforms of the SPC scheme: (

**a**) EB and UM both are in discharge mode; and (

**b**) EB is in discharge mode but UM is in charge mode.

**Figure 8.**Experimental waveforms of the SPC scheme. Steady states: (

**a**) ${i}_{EB}$ = 10 A, ${i}_{UM}$ = 10 A; and (

**b**) ${i}_{EB}$ = 3 A, ${i}_{UM}$ steps from 1 A to −1 A.

**Figure 10.**Difference between the losses in DPC and SPC configurations, as a function of the UM and EB currents. The darker areas correspond to SPC scheme operating with fewer losses than the original DPC scheme. For reference, it must be noted that ${P}_{Loss}$ equals to zero if ${i}_{UM}$ = 0 (i.e., horizontal axis).

**Figure 11.**Steady state losses comparison between DPC and SPC configurations: (

**a**) ${i}_{EB}$ = 0 A; (

**b**) ${i}_{EB}$ = 5 A; and (

**c**) ${i}_{EB}$ = 10 A. (

**d**) Efficiency measurements of the DPC and SPC schemes, for ${i}_{EB}$ = 5 A and ${i}_{EB}$ = 10 A.

**Figure 13.**Control schemes: (

**a**) Current control loop simplified scheme for tuning the regulator; and (

**b**) implemented control scheme, obtaining ${D}_{{3}_{D}}$ from the control action, ${U}_{{L}_{UM}}$.

Symbol | Parameter | Value |
---|---|---|

${u}_{EB}$ | Nominal Battery Voltage | 288 V |

${u}_{EB\_min}$ | Minimum Battery Voltage (0% SOC) | 225 V |

${u}_{EB\_max}$ | Maximum Battery Voltage (100% SOC) | 328 V |

${i}_{EB}$ | Battery Current | ±30 A |

${u}_{UM}$ | Rated UM Voltage | 48 V |

${i}_{UM}$ | UM Current | ±200 A |

${C}_{UM}$ | UM Capacitance | 165 F |

Symbol | Parameter | Value |
---|---|---|

${V}_{DC}^{\ast}$ | DC link Voltage | 600 V |

${R}_{LOAD}$ | DC load resistor | 300 $\mathsf{\Omega}$ |

${u}_{EB}$ | Battery Voltage | 300 V |

${i}_{EB}^{\ast}$ | Battery Current | 10 A |

${u}_{UM}$ | UM Voltage | 30 V |

${i}_{UM}^{\ast}$ | UM Current | 10 A |

${f}_{s}$ | Switching Frequency | 20 kHz |

${\mathit{i}}_{\mathit{EB}}^{\ast}$ (A) | ${\mathit{i}}_{\mathit{UM}}^{\ast}$ (A) | ${\mathit{P}}_{\mathit{Loss}}(\mathit{DPC})$ (W) | ${\mathit{P}}_{\mathit{Loss}}(\mathit{FBC})$ (W) | ${\mathit{\eta}}_{\mathit{DPC}}$ (%) | ${\mathit{\eta}}_{\mathit{FBC}}$ (%) |
---|---|---|---|---|---|

10 | 10 | 308.6 | 434.3 | 90.6% | 86.6% |

10 | 5 | 251.8 | 339.4 | 92.0% | 89.3% |

10 | 0 | 222.7 | 250.4 | 92.6% | 91.8% |

10 | −5 | 247.5 | 310.8 | 91.7% | 89.4% |

10 | −10 | 286.4 | 374.7 | 90.4% | 86.7% |

**Table 4.**Operating conditions of storage systems, considering references in Figure 6.

EB | UM | Operating Condition |
---|---|---|

Discharging ${i}_{EB}$ > 0 | Charging ${i}_{UM}$ < 0 | Opposite sign in currents |

Discharging ${i}_{EB}$ > 0 | Discharging ${i}_{UM}$ > 0 | Same sign in currents |

Charging ${i}_{EB}$ < 0 | Charging ${i}_{UM}$ < 0 | Same sign in currents |

Charging ${i}_{EB}$ < 0 | Discharging ${i}_{UM}$ > 0 | Opposite sign in currents |

${\mathit{i}}_{\mathit{EB}}^{\ast}$ (A) | ${\mathit{i}}_{\mathit{UM}}^{\ast}$ (A) | ${\mathit{P}}_{\mathit{Loss}}(\mathit{DPC})$ (W) | ${\mathit{P}}_{\mathit{Loss}}(\mathit{SPC})$ (W) | $\mathbf{\Delta}{\mathit{P}}_{\mathit{Loss}}$ (W) | ${\mathit{\eta}}_{\mathit{DPC}}$ (%) | ${\mathit{\eta}}_{\mathit{SPC}}$ (%) |
---|---|---|---|---|---|---|

0 | 10 | 142.0 | 248.6 | 106.6 | - | - |

0 | 5 | 82.0 | 147.9 | 65.9 | - | - |

0 | 0 | 20.3 | 15.1 | −5.3 | - | - |

0 | −5 | 99.8 | 55.3 | −44.5 | - | - |

0 | −10 | 206.0 | 250.8 | 44.8 | - | - |

5 | 10 | 240.1 | 224.4 | −15.7 | 87.0% | 87.4% |

5 | 5 | 177.8 | 139.0 | −38.8 | 89.5% | 91.6% |

5 | 0 | 146.0 | 138.3 | −7.7 | 90.5% | 91.0% |

5 | −5 | 166.0 | 191.8 | 25.9 | 89.1% | 87.4% |

5 | −10 | 188.1 | 277.5 | 89.4 | 87.5% | 81.9% |

10 | 10 | 308.6 | 257.2 | −51.5 | 90.6% | 92.1% |

10 | 5 | 251.8 | 218.7 | −33.1 | 92.0% | 93.1% |

10 | 0 | 222.7 | 215.9 | −6.9 | 92.6% | 92.9% |

10 | −5 | 247.5 | 293.9 | 46.4 | 91.7% | 90.3% |

10 | −10 | 286.4 | 363.9 | 77.5 | 90.4% | 88.0% |

Parameter | DPC | FBC | SPC |
---|---|---|---|

Efficiency | Baseline for comparison | Smaller than DPC | Depends on currents sign |

Electr. and therm. stress balancing | High mismatch in ${K}_{f}$ at switches | ${K}_{f}$ at switches evenly distributed | ${K}_{f}$ at switches evenly distributed |

Control regulation margins | Non-symmetric current control, lim. bandwidth | Symmetrical current control | Symmetrical current control |

Control simplicity | Simple, independent current control for EB and UM | ||

Current ripple through UM | Baseline for comparison at switching frequency | Ripple at twice the switching frequency | Ripple at twice the switching frequency |

Current ratings at EB leg switches | Rated for EB peak current | Rated for EB peak current | Rated for algebraic sum at UM and EB peak currents |

Size | Baseline for comparison | Increased No. of legs | Same legs than DPC, smaller UM inductor |

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Georgious, R.; Garcia, J.; Garcia, P.; Navarro-Rodriguez, A.
A Comparison of Non-Isolated High-Gain Three-Port Converters for Hybrid Energy Storage Systems. *Energies* **2018**, *11*, 658.
https://doi.org/10.3390/en11030658

**AMA Style**

Georgious R, Garcia J, Garcia P, Navarro-Rodriguez A.
A Comparison of Non-Isolated High-Gain Three-Port Converters for Hybrid Energy Storage Systems. *Energies*. 2018; 11(3):658.
https://doi.org/10.3390/en11030658

**Chicago/Turabian Style**

Georgious, Ramy, Jorge Garcia, Pablo Garcia, and Angel Navarro-Rodriguez.
2018. "A Comparison of Non-Isolated High-Gain Three-Port Converters for Hybrid Energy Storage Systems" *Energies* 11, no. 3: 658.
https://doi.org/10.3390/en11030658