Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging
State-of-the-art ultra-fast battery chargers for electric vehicles simultaneously require high efficiency and high power density, leading to a challenging power converter design. In particular, the grid-side filter, which ensures sinusoidal current absorption with low pulse-width modulation (PWM) ha...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-02-01
|
| Series: | Energies |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1073/14/5/1303 |
| _version_ | 1797417488730816512 |
|---|---|
| author | Davide Cittanti Fabio Mandrile Matteo Gregorio Radu Bojoi |
| author_facet | Davide Cittanti Fabio Mandrile Matteo Gregorio Radu Bojoi |
| author_sort | Davide Cittanti |
| collection | DOAJ |
| description | State-of-the-art ultra-fast battery chargers for electric vehicles simultaneously require high efficiency and high power density, leading to a challenging power converter design. In particular, the grid-side filter, which ensures sinusoidal current absorption with low pulse-width modulation (PWM) harmonic content, can be a major contributor to the overall converter size and losses. Therefore, this paper proposes a complete analysis, design and optimization procedure of a three-phase LCL filter for a modular DC fast charger. First, an overview of the basic LCL filter modeling is provided and the most significant system transfer functions are identified. Then, the optimal ratio between grid-side and converter-side inductance is discussed, aiming for the maximum filtering performance. A novel design methodology, based on a graphical representation of the filter design space, is thus proposed. Specifically, several constraints on the LCL filtering elements are enforced, such that all feasible design parameter combinations are identified. Therefore, since in low-voltage high-power applications the inductive components typically dominate the overall filter volume, loss and cost, the viable LCL filter design that minimizes the total required inductance is selected. The proposed design procedure is applied to a 30 kW, 20 kHz 3-level unidirectional rectifier, employed in a modular DC fast charger. The performance of the selected optimal design, featuring equal grid-side and converter-side 175 <inline-formula>μ<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>H inductors and 15 <inline-formula>μ<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>F capacitors, is verified experimentally on an active front-end prototype, both in terms of harmonic attenuation capability and current control dynamics. A current total harmonic distortion (THD) of 1.2% is achieved at full load and all generated current harmonics comply with the applicable harmonic standard. Moreover, separate tests are performed with different values of grid inner impedance, verifying the converter control stability in various operating conditions and supporting the general validity of the proposed design methodology. |
| first_indexed | 2024-03-09T06:20:28Z |
| format | Article |
| id | doaj.art-1f0043ce68184cfc88993f818720d883 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-09T06:20:28Z |
| publishDate | 2021-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-1f0043ce68184cfc88993f818720d8832023-12-03T11:48:16ZengMDPI AGEnergies1996-10732021-02-01145130310.3390/en14051303Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery ChargingDavide Cittanti0Fabio Mandrile1Matteo Gregorio2Radu Bojoi3Energy Department “Galileo Ferraris”, Politecnico di Torino, 10129 Torino, ItalyEnergy Department “Galileo Ferraris”, Politecnico di Torino, 10129 Torino, ItalyEnergy Department “Galileo Ferraris”, Politecnico di Torino, 10129 Torino, ItalyEnergy Department “Galileo Ferraris”, Politecnico di Torino, 10129 Torino, ItalyState-of-the-art ultra-fast battery chargers for electric vehicles simultaneously require high efficiency and high power density, leading to a challenging power converter design. In particular, the grid-side filter, which ensures sinusoidal current absorption with low pulse-width modulation (PWM) harmonic content, can be a major contributor to the overall converter size and losses. Therefore, this paper proposes a complete analysis, design and optimization procedure of a three-phase LCL filter for a modular DC fast charger. First, an overview of the basic LCL filter modeling is provided and the most significant system transfer functions are identified. Then, the optimal ratio between grid-side and converter-side inductance is discussed, aiming for the maximum filtering performance. A novel design methodology, based on a graphical representation of the filter design space, is thus proposed. Specifically, several constraints on the LCL filtering elements are enforced, such that all feasible design parameter combinations are identified. Therefore, since in low-voltage high-power applications the inductive components typically dominate the overall filter volume, loss and cost, the viable LCL filter design that minimizes the total required inductance is selected. The proposed design procedure is applied to a 30 kW, 20 kHz 3-level unidirectional rectifier, employed in a modular DC fast charger. The performance of the selected optimal design, featuring equal grid-side and converter-side 175 <inline-formula>μ<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>H inductors and 15 <inline-formula>μ<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>F capacitors, is verified experimentally on an active front-end prototype, both in terms of harmonic attenuation capability and current control dynamics. A current total harmonic distortion (THD) of 1.2% is achieved at full load and all generated current harmonics comply with the applicable harmonic standard. Moreover, separate tests are performed with different values of grid inner impedance, verifying the converter control stability in various operating conditions and supporting the general validity of the proposed design methodology.https://www.mdpi.com/1996-1073/14/5/1303LCL filtersgrid-connected convertersactive front-end (AFE)power factor corrector (PFC)battery chargingultra-fast charging (UFC) |
| spellingShingle | Davide Cittanti Fabio Mandrile Matteo Gregorio Radu Bojoi Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging Energies LCL filters grid-connected converters active front-end (AFE) power factor corrector (PFC) battery charging ultra-fast charging (UFC) |
| title | Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging |
| title_full | Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging |
| title_fullStr | Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging |
| title_full_unstemmed | Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging |
| title_short | Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging |
| title_sort | design space optimization of a three phase lcl filter for electric vehicle ultra fast battery charging |
| topic | LCL filters grid-connected converters active front-end (AFE) power factor corrector (PFC) battery charging ultra-fast charging (UFC) |
| url | https://www.mdpi.com/1996-1073/14/5/1303 |
| work_keys_str_mv | AT davidecittanti designspaceoptimizationofathreephaselclfilterforelectricvehicleultrafastbatterycharging AT fabiomandrile designspaceoptimizationofathreephaselclfilterforelectricvehicleultrafastbatterycharging AT matteogregorio designspaceoptimizationofathreephaselclfilterforelectricvehicleultrafastbatterycharging AT radubojoi designspaceoptimizationofathreephaselclfilterforelectricvehicleultrafastbatterycharging |