Variability Analysis of Efficiency and Output Power of an Inductive Power Transfer Link

An inductive power transfer (IPT) system has lower peak efficiency and significantly lower load-average efficiency over the entire range of output power than typical power conversion systems because it transmits power wirelessly through magnetically coupled coils. In order to improve the load-average efficiency of the IPT system, this paper proposes an integrated control strategy consisting of full-bridge, phase-shift, and half-bridge control modes. The coupling coefficient and output power conditions for each control mode are theoretically analyzed, and the proposed control algorithm is established. In order to verify the analysis results, a 3.3 kW IPT system prototype is constructed, and it is experimentally verified that the load-average efficiency is improved by up to 3.75% with respect to the output power when using the proposed control scheme. In addition, the proposed control has the additional advantage that it can be directly applied to the existing IPT system without changing or adding hardware.

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Development of a Digitally Controlled Inductive Power Transfer System with Post-Regulation for Variable Load Demand

Electronics ◽

10.3390/electronics11010058 ◽

2021 ◽

Vol 11 (1) ◽

pp. 58

Author(s):

Kateryna Stoyka ◽

Antonio Vitale ◽

Massimo Costarella ◽

Alfonso Avella ◽

Mario Pucciarelli ◽

...

Keyword(s):

Phase Shift ◽

Output Power ◽

Output Voltage ◽

Voltage Regulation ◽

Control Technique ◽

Switching Frequency ◽

Variable Load ◽

Power Transfer ◽

Inductive Power Transfer ◽

Inductive Power

Inductive Power Transfer (IPT) is an emerging technology enabling a contactless charging process in manifold applications such as electric vehicles, wearable and portable devices, or biomedical applications. Such technology can be profitably used to develop enhanced electronic solutions in the framework of smart cities, homes and smart workplaces. This paper presents the development and realization of a series–series compensated IPT System (IPTS) followed by a post-regulator implemented by means of a DC–DC converter. Such a system is modeled through a first harmonic approximation method, and a sensitivity analysis of the IPTS performance is carried out with respect to the variations of the primary inverter switching frequency and phase-shift angle. As an element of novelty of this work, the bias points are determined which allow the efficiency maximization while ensuring system controllability. An enhanced dynamic modeling of the system is then performed by means of a coupled mode theory, including the inverter phase-shift modulation and extending its validity to whatever operating frequency. A digital control of the post-regulator is implemented by means of a commercial low-cost microcontroller enabling the output voltage regulation under both fixed and variable load conditions through a voltage mode control technique. An IPTS prototype is eventually realized, which is able to correctly perform the output voltage regulation at the desired nominal value of 12 V for static resistive loads in the range [5,24] Ω, yielding the output power in the range [6, 28.8] W and the experimental efficiencies going from 72.1% (for 24 Ω) to 91.7% (for 5 Ω). The developed system can also be effectively used to deliver up to 35 W output power to variable loads, as demonstrated during the battery charging test. Finally, an excellent output voltage regulation is ascertained for load transients between 5 Ω and 24 Ω, with limited over- and undershoot amplitudes (less than 3% of the nominal output voltage), thus enabling the use of the proposed system for both fixed and variable loads in the framework of smart homes and workplaces applications.

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Output power increase of a series-series compensated inductive power transfer system via asymmetric loading

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe) ◽

10.1109/epe.2015.7309313 ◽

2015 ◽

Cited By ~ 4

Author(s):

Eleni Gati ◽

Georgios Kampitsis ◽

Stefanos Manias

Keyword(s):

Output Power ◽

Transfer System ◽

Power Transfer ◽

Inductive Power Transfer ◽

Asymmetric Loading ◽

Power Increase ◽

Inductive Power

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Magnetic Coupler Optimization for Inductive Power Transfer System of Unmanned Aerial Vehicles

Energies ◽

10.3390/en14217024 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7024

Author(s):

Xiaokun Li ◽

Junwei Lu ◽

Sascha Stegen

Keyword(s):

Unmanned Aerial Vehicles ◽

Output Power ◽

Magnetic Coupling ◽

Power Transfer ◽

Inductive Power Transfer ◽

Experimental Platform ◽

Aerial Vehicles ◽

Spiral Coils ◽

The Magnetic Field ◽

Inductive Power

Unmanned aerial vehicles (UAVs) have been widely used in military and civilian applications. However, the insufficient cruising range restricts the development of UAVs due to the limitation of their battery. Inductive power transfer (IPT) is an effective way to charge the battery and solve this problem. Magnetic coupler is a key component of the IPT system, which greatly affects the power transfer and efficiency of the IPT. This paper proposes a new magnetic coupler with vertical spiral coils and ferrite PQI cores for the IPT system of UAVs, which can enhance the magnetic coupling and improve the performance of the IPT system. Finite element simulations are used to investigate the magnetic field distribution and coupling capability of the proposed magnetic coupler. In addition, an experimental platform is built to prove the validity of the IPT system using the proposed magnetic coupler. The results show that the coupling coefficient can reach 0.98, and the system transfer efficiency is 89.27% with an output power of 93 W. The IPT system also has a perfect misalignment tolerance and can achieve a stable output power.

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Analysis of LC-LC2 Compensated Inductive Power Transfer for High Efficiency and Load Independent Voltage Gain

Energies ◽

10.3390/en11112883 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2883 ◽

Cited By ~ 3

Author(s):

Md Alam ◽

Saad Mekhilef ◽

Hussain Bassi ◽

Muhyaddin Rawa

Keyword(s):

Output Power ◽

High Efficiency ◽

Domain Analysis ◽

Air Gap ◽

Similar Amount ◽

Voltage Gain ◽

Resonant Converter ◽

Power Transfer ◽

Inductive Power Transfer ◽

Inductive Power

A novel LC-LC2 compensated resonant converter topology with high efficiency and good controllable voltage gain is presented in this paper. An additional receiving side inductor working together with the receiving coil has the contribution to work with a large range of air gap distance. Due to this property, proposed compensation technique is effective for IPT based EV charging application. Voltage gain with independent of load and input impedance having ZPA of the proposed resonant converter are observed by the frequency domain analysis. On the other hand, time domain analysis gives the circuit operation. A 500 W LC-LC2 compensated resonant converter prototype is built to testify the theoretical analysis. To observe the efficiency-comparison, an S-SP compensated resonant converter with a similar amount of output power under different air gap is also presented. In order to justify the effectiveness, the proposed compensation method is verified by the laboratory results. The highest efficiency of the proposed compensated resonant converter is 93% with output power of 500 W at 140-mm air gap between the two sides of the IPT (inductive power transfer) transformer.

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Effect of tuning capacitance of passive power repeaters on power transfer capability of inductive power transfer systems

Wireless Power Transfer ◽

10.1017/wpt.2018.3 ◽

2018 ◽

Vol 5 (2) ◽

pp. 97-104

Author(s):

Rong Hua ◽

Aiguo Patrick Hu

Keyword(s):

Output Power ◽

Secondary Coil ◽

Power Transfer ◽

Primary Coil ◽

Inductive Power Transfer ◽

Optimal Tuning ◽

Transfer Capability ◽

Passive Power ◽

The Relationship ◽

Inductive Power

Power repeaters are used to extend the power transfer range or enhance the power transfer capability of Inductive Power Transfer (IPT) systems, but how to tune the power repeaters to improve the system power transfer performance remains an unsolved problem. In this paper, studies of the effect of the tuning capacitance of the power repeater of an IPT system on the power transfer capability are presented. A theoretical model is established to analyze the output power of the system with the primary coil and secondary coil tuned at a nominal resonant frequency, and a passive power repeater placed in between. By analyzing the relationship between the tuning capacitance of the power repeater and the output power, a critical tuning capacitance which sets up the boundary between enhancing and reducing the output power is determined, and the optimal tuning capacitances corresponding to the maximum and minimum output power are also obtained. A practical IPT system with a passive power repeater placed at 40, 80, and 104 mm from the primary coil is built. It has shown that the practically measured critical capacitance and the optimal tuning capacitance for maximum power transfer are in good agreement with the analytical results.

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An Improved Autonomous Current-Fed Push-Pull Parallel-Resonant Inverter for Inductive Power Transfer System

Energies ◽

10.3390/en11102653 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2653 ◽

Cited By ~ 2

Author(s):

Anning Yu ◽

Xiaoping Zeng ◽

Dong Xiong ◽

Mi Tian ◽

Junbing Li

Keyword(s):

Output Power ◽

Input Voltage ◽

Resonant Circuit ◽

Power Transfer ◽

Inductive Power Transfer ◽

Resonant Inverter ◽

Switching Losses ◽

Wide Range ◽

Overall Efficiency ◽

Inductive Power

In the inductive power transfer (IPT) system, it is recommended to drive the resonant inverter in zero-voltage switching (ZVS) or zero-current switching (ZCS) operation to reduce switching losses, especially in dynamic applications with variable couplings. This paper proposes an improved autonomous current-fed push-pull parallel-resonant inverter, which not only realizes the ZVS operation by tracking the zero phase angle (ZPA) frequency, but also improves the output power and overall efficiency in a wide range by reducing gate losses and switching losses. The ZPA frequencies characteristic of the parallel-parallel resonant circuit in both bifurcation and bifurcation-free regions is derived and verified by theory and experiments, and the comparative experimental results demonstrate that the improved inverter can significantly increase the output power from 7.68 W to 8.74 W and has an overall efficiency ranging from 63.5% to 72.5% compared with the traditional inverter at a 2 cm coil distance. Furthermore, with a 2-fold input voltage (24 V), the improved inverter can achieve an approximate 4-fold output power of 38.9 W and overall efficiency of 83.6% at a 2 cm coil distance.

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Analysis of LC-LC2 Compensated Inductive Power Transfer for High Efficiency and Load Independent Voltage Gain

10.20944/preprints201807.0031.v1 ◽

2018 ◽

Author(s):

Md Morshed Alam ◽

Saad Mekhilef

Keyword(s):

Output Power ◽

High Efficiency ◽

Domain Analysis ◽

Air Gap ◽

Maximum Efficiency ◽

Voltage Gain ◽

Resonant Converter ◽

Power Transfer ◽

Inductive Power Transfer ◽

Inductive Power

This paper presents a novel LC-LC2 compensated resonant converter topology to achieve both high efficiency and good voltage gain controllability. An additional receiving side inductor working together with the receiving coil has the contribution to work with a large range of air gap distance. Due to this property, proposed compensation technique is effective for IPT based EV charging application. The frequency domain analysis of the proposed resonant converter provides the load independent voltage gain and ZPA of the input impedance. On the other hand, time domain analysis gives the circuit operation. A 500 W LC-LC2 compensated resonant converter prototype is built to testify the theoretical analysis. To perform the efficiency-comparison under different air gap, an S-SP compensated resonant converter with a similar amount of output power is also presented. In order to obtain the effectiveness, the proposed compensation method is verified by the experimental results. The maximum efficiency of the proposed compensated resonant converter is 93% at an output power of 500 W with a 140-mm air gap between the two sides of the IPT (inductive power transfer) transformer.

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