Battery Charge Applications Based on Wide Output Voltage Range

In this study, high efficiency design procedure of a phase shifted full bridge (PSFB) converter is presented for on-board electrical vehicle (EV) battery charger. Presented design methodology used lithium-ion battery cells because of their high voltage and current rates compared to a lead-acid battery cells. In this case, PSFB converter can be regulated wide range output voltage with while its soft switching operation is maintained. The basic operation principles of PSFB converter is defined and its soft switching operation requirements are given. To evaluate the performance of the converter over wide output voltage range, zero voltage switching (ZVS) operation of converter is discussed based on dead time requirement. To improve efficiency, the snubber inductance effects on soft switching over wide output voltage range are evaluated. Finally, operation of the PSFB converter is validated experimentally with a prototype which has 42-54 V/15 A output range at 200 kHz switching frequency

Elektrikli araç yerleşik batarya şarj uygulamaları için yüksek verimli bir LLC rezonanslı DC-DC dönüştürücünün tasarım yaklaşımı

In this study, an optimal design procedure of inductor-inductor-capacitor (LLC) resonant converter for on-board electrical vehicle (EV) battery charge applications based on high efficiency is proposed. In the design procedure, lithium-ion battery cells are used due to their high power density, higher voltage and current rates compared to a lead-acid battery cells. Thus, LLC resonant converter should be regulated the output voltage in a wide voltage range with different load conditions according to typical charging profile of lithium-ion battery. For the design procedure, basic operation characteristics of LLC resonant converter is defined and operation regions are discussed in terms of high efficiency. The operation regions of LLC resonant converter are discussed to regulate wide output voltage range. In order to reach high efficiency optimal design, efficiency calculations based on Saber simulation are extracted for discussed operation regions. The best efficiency values are obtained for the operation of above-below resonance. Finally, soft switching operation of the LLC resonant converter is validated by Saber simulation for wide output voltage range and with changing load current

Iterative Design of a 60 kW All-Si Modular LLC Converter for Electric Vehicle Ultra-Fast Charging

This paper proposes an iterative design procedure for a high-power LLC resonant converter, taking part in a 60 kW modular DC/DC conversion stage for an electric vehicle (EV) ultra-fast battery charger. The basics of operation of the LLC converter are briefly recalled and the most relevant analytical expressions are reported. Due to the high-power requirement and the wide output battery voltage range (i.e. 250-1000 V), a modular design approach is adopted, leveraging the split input DC-link structure provided by a 3-level active front-end. A total of four modules, with at 15 kW nominal power and a 250-500 V output voltage regulation capability, are designed with a straightforward iterative procedure based on the first-harmonic approximation (FHA). Finally, the proposed methodology is verified experimentally on a 15 kW LLC converter prototype directly resulting from the design procedure

Digital Multi-Loop Control of an LLC Resonant Converter for Electric Vehicle DC Fast Charging

This paper proposes a digital control strategy for LLC resonant converters, specifically intended for EV battery charging applications. Two cascaded control loops, i.e. an external battery voltage loop and an internal battery current loop, are designed and tuned according to analytically derived expressions. Particular attention is reserved to the output current control analysis, due to its extremely non-linear behaviour. The well known seventh-order LLC small-signal model, derived with the extended describing function (EDF) method, is simplified to an equivalent first-order model at the resonance frequency. In theseconditions,whichareproventobethemostunderdamped, the current control loop is tuned taking into account the delays introduced by the digital control implementation. Moreover, the adoption of a look-up table (LUT) in the feed-forward path is proposed to counteract the system non-linearities, ensuring high dynamical performance over the full frequency operating range. Finally, the proposed control strategy and controller design procedure are verified both in simulation and experimentally on a 15 kW LLC converter prototype

Optimal design of line level control resonant converters in plug‐in hybrid electric vehicle battery chargers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163784/1/els2bf00015.pd

Analysis, Design and Control of a Modular Full-Si Converter Concept for Electric Vehicle Ultra-Fast Charging

L'abstract è presente nell'allegato / the abstract is in the attachmen

Study of a Symmetrical LLC Dual-Active Bridge Resonant Converter Topology for Battery Storage Systems

A symmetrical LLC resonant converter topology with a fixed-frequency quasi-triple phase-shift modulation method is proposed for battery-powered electric traction systems with extensions to other battery storage systems. Operation of the converter with these methods yields two unique transfer characteristics and is dependent on the switching frequency. The converter exhibits several desirable features: 1) load-independent buck-boost voltage conversion when operated at the low-impedance resonant frequency, allowing for dc-link voltage regulation, zero-voltage switching across a wide load range, and intrinsic load transient resilience; 2) power flow control when operated outside the low-impedance resonance for integrated battery charging; 3) and simple operational mode selection based on needed functionality with only a single control variable per mode. Derivation of the transfer characteristics for three operation cases using exponential Fourier series coefficients is presented. Pre-design evaluation of the S-LLC converter is presented using these analytical methods and corroborated through simulation. Furthermore, the construction of a rapid-prototyping magnetics design tool developed for high-frequency transformer designs inclusive of leakage inductance, which is leveraged to create the magnetic elements needed for this work. Two 2kW prototypes of the proposed topology are constructed to validate the analysis, with one prototype having a transformer incorporating the series resonant inductance and secondary clamp inductance into the transformer leakage and magnetizing inductance, respectively. A test bench is presented to validate the analysis methods and proposed multi-operational control scheme. Theoretical and experimental results are compared, thus demonstrating the feasibility of the new multi-mode operation scheme of the S-LLC converter topology