Precise analysis of frequency splitting phenomenon of magnetically coupled wireless power transfer system

Esfahani, Fatemeh Nasr; Madani, Mohammad; Niroomand, Mehdi

doi:10.1109/apmc.2017.8251418

Cited by 9 publications

(7 citation statements)

References 20 publications

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“…Wh there is an offset between the receiving and transmitting coils, the power transmission Underwater wireless power transmission can be widely used in autonomous underwater vehicles (AUVs) and robots and can also provide reliable energy supply for ocean observation and monitoring systems. A typical magnetic coupling resonant underwater wireless power transfer system comprises four parts: a high-frequency inverter circuit, a coupling mechanism, a compensation network, and a high-frequency rectifier circuit [25][26][27][28]. The transmitting end is provided with DC input by the underwater cable or the mother ship.…”

Section: Acmentioning

confidence: 99%

“…To achieve this, an appropriate multi-resonance point switching strategy should be adopted. According to Formulas (24) and (25), the output power is not only related to the resonance frequency but also to the coupling coefficient. The output power under the resonance frequency ω 1 decreases with the decrease in the coupling coefficient, while the output power under the resonance frequency ω 2 increases with the decrease in the coupling coefficient.…”

Section: Analysis Of Constant Voltage Output Characteristics Of Multi...mentioning

confidence: 99%

“…The transmission capability of the lower system at resonance frequency ω 1 is significantly enhanced, such that the transmission power and transmission efficiency of the system can be increased through multi-resonance point switching. It can be seen from Formula ( 22) that the higher the coupling coefficient is, the higher the output voltage is; while Formula (23) indicates that the lower the coupling coefficient is, the higher the output voltage is; Formula (24) indicates that the higher the coupling coefficient is, the higher the system transmission power; and Formula (25) indicates that the lower the coupling coefficient is, the higher the system transmission power is, which is the same as the simulation results. It can also be seen from the figure that the coupling coefficient at the lowest power point and the efficiency point is 0.4, which is the same as the calculation result of Equation ( 26) and is obviously the switching point of the resonant frequency.…”

Section: Simulating Output Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Research on Double LCC Compensation Network for Multi-Resonant Point Switching in Underwater Wireless Power Transfer System

Zhou,

Qiu,

Wang

et al. 2023

Electronics

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This paper introduces a control method suitable for AUVs to transmit underwater radio energy that improves the stability of AUV charging under water based on double LCC compensation. The coupling coefficient decreases with the rise of the coil offset in the underwater wireless power transfer system, such that the power transmission capability is reduced. To solve the above-mentioned problem, a double LCC resonant compensation network impedance characteristic is proposed in this study through the analysis of the double LCC resonant compensation network. To be specific, the wireless power transmission method for multi-resonant point switching of the LCC compensation network is developed. The multiple resonance points of the developed method are not correlated with the load impedance in the double LCC resonance compensation network, and the multiple resonance points are consistent with the power transmission characteristics. Moreover, the appropriate resonance frequency is matched based on different coupling coefficients, and the multi-resonance points are switched to each other to increase the system’s transmission power and transmission efficiency. As revealed by the results of the simulation and experimental studies, the double LCC compensation network with multi-resonance point switching is capable of achieving the output characteristics of constant-voltage/constant-current of the wireless power transfer system, reducing the system current harmonics effectively, and enhancing the power transmission capability and anti-offset capability.

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Section: Acmentioning

confidence: 99%

Section: Analysis Of Constant Voltage Output Characteristics Of Multi...mentioning

confidence: 99%

Section: Simulating Output Characteristicsmentioning

confidence: 99%

See 1 more Smart Citation

Research on Double LCC Compensation Network for Multi-Resonant Point Switching in Underwater Wireless Power Transfer System

Zhou,

Qiu,

Wang

et al. 2023

Electronics

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show abstract

“…As seen, for coupling coefficients smaller than k = 0.15, the transferred power is low at f / f s due to the weak coupling between the coupled coils. For coupling coefficients larger than k = 0.15, the transferred power at f / f s is also low due to the frequency splitting phenomenon [11,20,23,24]. While this phenomenon is happening, as a result of impedance matching problem in short coil-coil distance (in the strongly coupled region), the maximum power is transferred at splitting frequencies instead of the natural resonant frequency f s [16].…”

Section: Tracking Maximum Efficiency Point During Variations In Coil-mentioning

confidence: 99%

Dual‐objective control strategy for maximum power and efficiency point tracking in wirelessly powered biomedical implanted devices

Esfahani

Madani

Niroomand

2019

IET Microwaves, Antennas & Propagation

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Wireless charging is widely considered as a safe and reliable way for powering biomedical implants, as it avoids problems like surgical infection. Wireless power transfer (WPT) systems are desired to work efficiently against variations in coil–coil distance or output load. On the other hand, to maintain the maximum overall efficiency of the WPT system, the high frequency (HF) power amplifier, used to feed WPT system, must operate at optimal zero‐voltage switching (ZVS) condition. In this paper, an automated dual‐objective control strategy adaptive to variations in coil–coil distance or output load is proposed which ensures both targets of tracking maximum power point and operating at optimal ZVS condition by adjusting operating frequency and duty‐cycle of switching voltage of HF power amplifier, respectively; that is while there have been few studies which have addressed both the two targets. To evaluate the effectiveness of the proposed strategy, a PCB prototype, operating at 800 kHz, is fabricated. Experimental results, demonstrating the proposed strategy increases transferred power from 23 mW to about 45 mW, are in good agreement with theoretical predictions. Additionally, while implanting the receiver coil in a real biological tissue, experiments show only 2% of degradation in power transfer efficiency as well as no frequency shift.

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“…Outside the critical-coupling region, a larger coil-to-coil distance degrades the power delivery due to the lower coupling factor (in the weakly-coupled region) [11]. Also, when the coil-to-coil distance decreases below the critical distance, the coupling factor becomes large and results in an unexpected reduction of the efficiency of power transmitted η W P T due to the frequency splitting phenomenon (in the strongly-coupled region) [8], [12], [13], [14].…”

mentioning

confidence: 99%

Maximum Wireless Power Transmission Using Real-Time Single Iteration Adaptive Impedance Matching

Esfahani

Madani

Niroomand

et al. 2023

IEEE Trans. Circuits Syst. I

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Wireless power transfer (WPT) systems' efficiency is significantly impacted by non-monotonic variations in the coupling coefficient. For very short distances or strong-coupling cases, the WPT efficiency is minimal at the natural resonant frequency, with two peaks around this frequency, known as the frequency splitting phenomenon. On the other hand, WPT capability decreases for long distances or weak coupling cases. Therefore, adaptive matching is required for WPT systems with varying distances, like wireless charging systems for electric vehicles (EVs). This paper first presents a detailed analysis of the frequency splitting phenomenon by studying the root locations of the WPT system's transfer function. Then, a real-time fixedfrequency adaptive impedance matching (IM) method is proposed, in which the amplitude and phase of the input impedance is estimated using the average active power, the average reactive power, and the amplitude of input voltage. Unlike traditional search-and-find techniques, the proposed method calculates the optimal IM network parameters only in a single iteration, which improves the convergent speed. A scaled-down 20-Watt prototype controlled by the TMSF2812 is fabricated and used to validate the effectiveness of the proposed method over a wide range of coil-to-coil distances.

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Precise analysis of frequency splitting phenomenon of magnetically coupled wireless power transfer system

Cited by 9 publications

References 20 publications

Research on Double LCC Compensation Network for Multi-Resonant Point Switching in Underwater Wireless Power Transfer System

Research on Double LCC Compensation Network for Multi-Resonant Point Switching in Underwater Wireless Power Transfer System

Dual‐objective control strategy for maximum power and efficiency point tracking in wirelessly powered biomedical implanted devices

Maximum Wireless Power Transmission Using Real-Time Single Iteration Adaptive Impedance Matching

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