IEEE Trans. The short-circuit inductance Lsc2 and the resonance capacitor Cr on the secondary side resonate. Wireless power transfer - Inductive vs. resonant mode Accessed 14 November 2020, S. Li, C.C. 576), AI/ML Tool examples part 3 - Title-Drafting Assistant, We are graduating the updated button styling for vote arrows. That is, the first condition for PTE maximization \(\omega _0 L_2 = -X\) also holds for TP maximization. What really happen with resonance inductive coupling Entropy 20(9), 714 (2018), E. Guariglia, Primality, fractality, and image analysis. However, a high bandwidth B does not directly describe the frequency characteristics of the information-containing sidebands. Such modulation would cause further spectral lines around the sidebands. The resistances \(R_1\) and \(R_2\) describe the ohmic losses of the two coils. At port 1, the characteristic impedance is usually assumed to be \(R_{01}=R_0\) unless denoted otherwise. 12, follows as. These sidebands may even lie outside the bandwidth, indicating the 3 dB damping around the carrier frequency. Springer Proceedings in Mathematics and Statistics 179, 337353 (2016), X. Zheng, Y.Y. Sensors 18(11), 3746 (2018), H. Kim, H. Hirayama, S. Kim, K.J. . And the Japanese Ministry of Land, Infrastructure and Transportation evaluated the technology as all the problems for practical use were cleared. In 2011, they succeeded in powering while driving (CWD:charge while driving) across a large gap by the JR Tokai proprietary 9.8kHz phase synchronization technology developed based on technology similar to AGV's wireless power scheme. EURASIP Journal on Wireless Communications and Networking 2021, Article number: 121 ( 2021 ) Cite this article 10k Accesses 5 Citations Metrics Abstract This paper gives an overview of optimizing wireless power transfer systems using magnetic coupling. The two sidebands of the backscattered signal at \(f_0+847.5\) kHz and \(f_0-847.5\) kHz in Fig. Moreover, fractal geometries represent another research area that could be applied for designing antennas with multiple resonances [23, 24]. The more flux reaches the receiver, the better the coils are coupled. This results in a remaining imaginary impedance part on the secondary side for the parallel case. When coupling is small (k < 0.01) there is quite a tight central peak (about 10 MHz) but as coupling gets larger, the central peak splits into two peaks that start to move away from each other as coupling improves so, you could choose to drive the primary at a slightly lower or a slightly higher frequency than 10 MHz and get an improvement in co. [4][5][20] It was putting into practical use as the moving crane and the AGV non-contact power supply in Japan. However, a low Q and, thus, high B still indicates more or less flat frequency characteristics. The research on different ways of WPT is presented; their drawbacks and future prospective are presented in the paper. 5 shows the maximum achievable PTE over different coupling factors k. Figure6 shows the PTE over the coupling factor k and resistance R for a constant frequency \(f_0={13.56}\,\mathrm{MHz}\). The analysis of the power transfer and efficiencies below uses the equivalent circuit in Fig. \end{aligned}$$, $$\begin{aligned} \hbox{TP}=\frac{P_{\rm out}}{P_{\rm available}}=\frac{|I_2|^2 R}{|U_0|^2 /(4 R_0)}. IEEE J. For inductive coupling, the focus of this paper, Fig. 2, including source, load, primary and secondary coils and matching networks for the primary and secondary sides. There, sidebands are generated by switching between two different complex-valued RCSs of the tag antenna. Making statements based on opinion; back them up with references or personal experience. The first condition for maximizing the PTE is to completely remove the imaginary impedance part on the secondary side of the WPT system. In [8], an overview of NFC sensors for IoT applications is given, highlighting inductive coupling issues such as the quality factor and bandwidth. 3 the two strategies of maximizing either the power transfer efficiency or the transferred power are compared. In what follows, sideband generation by means of switching between different load resistances in an RFID tag is examined. This degradation results from the dielectric . volume2021, Articlenumber:121 (2021) In situations where a source of power is available nearby, it can be a cheaper solution. Others operate at higher kilowatt power levels. \end{aligned}$$, \(\omega _0 L_2 = \frac{1}{\omega _0 C_{2s}}= \frac{1}{\omega _0 C_{2p}}\), $$\begin{aligned} \begin{bmatrix} b_1 \\ b_2 \end{bmatrix} = \begin{bmatrix} S_{11} &{} S_{12} \\ S_{21} &{} S_{22} \end{bmatrix} \begin{bmatrix} a_1 \\ a_2 \end{bmatrix} = S \begin{bmatrix} a_1 \\ a_2 \end{bmatrix}, \end{aligned}$$, $$\begin{aligned} a_2 = b_2r_L, \quad r_L = \frac{R_L-R_{02}}{R_L+R_{02}}, \quad b_2 = \frac{a_1S_{21}}{1-r_LS_{22}}. UC Berkeley Path Program Technical Report: UCB-ITS-PRR-94-07. Notice how the phase in Figure 14 is -90 degrees between the resonant peaks. Finally, the complex-valued voltage amplitude at port 1, which is, can be written for the three frequency components the carrier frequency and the two sidebands as. In the first case, using the series capacitor \(C_{1s}\) on the primary side, matching follows directly by first satisfying \(\omega _0 L_1 = \frac{1}{\omega _0 C_{1s}}\), resulting in. Thus, the mismatch between the source and the remaining network is taken into account. Resonant inductive coupling or magnetic phase synchronous coupling[4][5] is a phenomenon with inductive coupling in which the coupling becomes stronger when the "secondary" (load-bearing) side of the loosely coupled coil resonates. Here, the load resistance \(R_L\) and the matching network on the secondary side are combined to a complex load \(Z=R+jX\). Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. Comparison Study of Inductive Coupling and Magnetic Resonant Coupling Pozar, Microwave Engineering (Wiley, Hoboken, NJ, 2012). https://airfuel.org. \end{aligned}$$, $$\begin{aligned} B_{\rm tag}=\frac{f_0}{Q}=\frac{2\pi f_0^2 L_2}{R_L}, \end{aligned}$$, $$\begin{aligned} s_c(t) = \mathfrak {R}\{a_1 S_{21}e^{j\omega _0 t}\}. Returning to the TP depicted with respect to frequency in Fig. The WiTricity type magnetic resonance is characterized in that the resonant coils on the primary side and the resonant coils on the secondary side are paired. For optimizing load modulation in such scenarios, complex-valued coupling between the RFID reader and tag, including a complex-valued RCS for the RFID tag, was introduced in [13]. Resonant transformers are widely used in radio circuits as bandpass filters, and in switching power supplies. For strong coupling with \(k=0.3\), we can also see in Fig. So i know the formula V = IR, so i need: 4(V) = IR, and how do I get the ampere(A) and the minimum resistance(R) (to keep the resonance peaks, as you told me). Constant load \(R_L={2.4} \ {\mathrm{k}\Omega }\) with series matching on the primary and parallel matching on the secondary, TP over frequency for series-compensated primary side and parallel-compensated secondary. The short-circuit inductance Lsc2 on the secondary side can be obtained by the following formula. Tentzeris, Ambient RF energy-harvesting technologies for self-sustainable standalone wireless sensor platforms. For data transmission, the bandwidth is directly related to the data rate. 49, 47805, Krefeld, Germany, You can also search for this author in This modulated signal sends a backscattered signal back to the RFID reader. The coupling factor depends on how the two coils are arranged with respect to each other. Semantic Scholar extracted view of "Mutual coupling reduction between closely spaced patch antennas using complementary electricfieldcoupled resonators" by Hayrettin Odabasi et al. Generally the voltage gain of non resonantly coupled coils is directly proportional to the square root of the ratio of secondary and primary inductances. Transferring electrical energy from the primary coil to the secondary coil by resonant induction, a Tesla coil is capable of producing very high voltages at high frequency. Mach. So if you paralleled impedance X with impedance -X you get: -. Troyk, "High efficiency driver for transcutaneously coupled coils" IEEE Engineering in Medicine & Biology Society 11th Annual International Conference, November 1989, pp. The power transfer efficiency (PTE) is defined as [2, 3], Maximizing the PTE refers to achieving energy efficiency with minimum system losses. With (1), k follows directly as, Alternatively, the resulting inductance \(L_S\) can be measured when the secondary coil is shorted (\(U_{L2}=0\)) [25]. For theoretical or simulation-based treatments of WPT systems, this assumption can be made easily. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 2 inductive coupling fundamentals are revisited. What is the difference between inductive coupling and - Answers For these approximations, thin wires and coil configurations with one radius much larger than the other are assumed. Different Types of Wireless Power Transfer Technologies and their Working An experimental electrified roadway test track built circa 1990 achieved just above 60% energy efficiency while recharging the battery of a prototype bus at a specially equipped bus stop. SCHWAN M. A. and P.R. Optimization aims to maximize either the power transfer efficiency or the transferred power. The most important parameters determining this efficiency are: (1) the coupling between transmitting and receiving coils, (2) the quality factors of the transmitting and receiving coils, (3) the number of receiving coils and (4) the matching of the receiving . Wireless power transfer (WPT) for battery charging using inductive links at high frequency (HF) is being standardized by the Wireless Power Consortium for operating frequencies in the range of 87205kHz [5]. Resonant inductive coupling - Wikipedia The range for such adapted parameters can become very small. The tag information is then carried by the subcarrier and appears as sidebands in the spectrum. Whether the coils are single turn loops with a tuning capacitor (suitable for higher frequencies) or multiple turn coils with a tuning capacitor is down to how the designer prefers things. The frequency characteristics of the scattering parameter \(S_{12}(f)\) cause the amount of distortion in the sideband signals to be transferred from the tag to the RFID reader. (2014). What is the difference between inductive coupling and magnetic coupling? Also, see. The energy will transfer back and forth between the magnetic field in the inductor and the electric field across the capacitor at the resonant frequency. Unlike the multiple-layer secondary of a non-resonant transformer, coils for this purpose are often single layer solenoids (to minimise skin effect and give improved Q) in parallel with a suitable capacitor. Your privacy choices/Manage cookies we use in the preference centre. The rest of this paper is organized as follows. rev2023.6.2.43474. Accessed 14 November 2020, AirFuel Alliance: The AirFuel Alliance. Alternatively, we could add another inductor in series with the source. Magnetic coupling between two magnets can also be used to mechanically transfer power without contact, as in the magnetic gear. \end{aligned}$$, $$\begin{aligned} \hbox{PTE}= & {} \frac{|S_{21}|^2}{1-|S_{11}|^2}, \end{aligned}$$, $$\begin{aligned} \hbox{TP}= & {} |S_{21}|^2. Covic, Design considerations for a contactless electric vehicle battery charger. Is abiogenesis virtually impossible from a probabilistic standpoint without a multiverse? Inductive coupling - Wikipedia What is the difference between inductive coupling and resonant By using this website, you agree to our Wireless chargers that implement PowerSphyr's magnetic resonance methods are more versatile. May I know what is the difference between magnetic and inductive coupling? Mi, Wireless power transfer for electric vehicle applications. Bottom: Coupling coefficient, Equivalent circuit. \(\rho _1=\rho _2={2.5}\ \mathrm{cm}\), \(N_1=N_2=1\) and \(r_0={0.1} \ \mathrm{mm}\). [citation needed] The LGR geometries have the advantage that electric fields outside the resonator structure are very weak which minimizes human exposure to electric fields and makes the power transfer efficiency insensitive to nearby dielectrics. The most basic resonant inductive coupling consists of one drive coil on the primary side and one resonance circuit on the secondary side. To remove energy from the secondary coil, different methods can be used, the AC can be used directly or rectified and a regulator circuit can be used to generate DC voltage. The resulting load calculation and matching strategies are revisited. A few questions regarding B/E-fields in practical circuitry. So I've shown Vin as the induced receiver voltage and on the output there is nearly a 40 dB increase in output voltage. Mude, Wireless power transfer for electric vehicle. \end{aligned} \end{aligned}$$, $$\begin{aligned} \hbox{PTE}_{\rm max}= \frac{\omega _0^2 M^2 R}{R_1 (R_2+R)^2 + \omega _0^2 M^2 (R_2+R)}. The resonant inductive coupling is better than inductive coupling, the difference between them, is that resonant inductive coupling use the "resonance" in their favor. Here, the output power at the load is normalized to the available source power. Maybe the problem is related to Q factor of Rx coil. Use ceramic capacitors X7R type should be fine. Anyone know what the problem is? Signal Process. In addition to wireless power transfer, communication in RFID and NFC systems and its frequency characteristics and bandwidth issues are highlighted. And the maximum achievable efficiency is:[39]. All other simulation parameters are set according to Table1. The upper figure shows the results for the simulation parameters that have been used up to now; for the lower figure, the source resistance is changed to \(R_0={5} \ {\Omega }\) and the adapted load resistance \(R_L={559} \ {\Omega }\) is optimized again according to (24) and (13). why do resonant inductive coupling circuit operate at high frequencies? Coupling coefficient of resonators - Wikipedia The voltage generated in the resonance capacitor Cr at the peak of the resonance frequency is proportional to the Q value. Bottom: Spectrum magnitude divided by the DFT size N. The formulas for the PTE and TP, in combination with the figures based on the specific simulation parameters in Table1, show the dependencies between the different system parameters. Cookies policy. Pabna University of Science and Technology Abstract and Figures Wireless power transfer via magnetic resonant coupling method and inductive coupling method has open new possibility to. I do not have much help from other people, thank you very much. Over greater distances the non-resonant induction method is highly inefficient and wastes the vast majority of the energy in resistive losses of the primary coil. The fields used are predominantly non-radiative, near fields (sometimes called evanescent waves), as all hardware is kept well within the 1/4 wavelength distance they radiate little energy from the transmitter to infinity. The value of k lies between 0 and 1. (PDF) Comparison Study of Inductive Coupling and Magnetic Resonant MathSciNet The reccomended solution for this problem is energy transfer through magnetic coupling. But efficiency is poor if distance is large. Playing a game as it's downloading, how do they do it? Inductive coupling for wireless power transfer and near-field \end{aligned} \end{aligned}$$, $$\begin{aligned} \begin{aligned} \hbox{PTE}&=\frac{P_{\rm out}}{P_{\rm in}}=\frac{P_{2}}{P_{1}}=\frac{|I_2|^2 R_L}{|I_1|^2 R_1 + |I_2|^2 R_2 + |I_2|^2 R_L}\\&= \frac{\omega ^2 M^2 R}{R_1\left( (R_2+R)^2 + (\omega L_2+X)^2 \right) + \omega ^2 M^2 (R_2+R)}. Accessed 14 November 2020, S. Kim, R. Vyas, J. Bito, K. Niotaki, A. Collado, A. Georgiadis, M.M. The authors declare that they have no competing interests. Extending the bandwidth definition to a 3 dB reduction compared to the maximum (instead of a single resonance), it can be seen that the bandwidth depends greatly on the coupling coefficient (here, a high bandwidth is obtained for \(k=0.3\)) and all other system parameters and not just, for example, on the bandwidth of the RFID tag, which is treated as a simple parallel resonance circuit [31]: where Q is the quality factor of the tag. How do you make a resonant inductive coupling? - Studybuff Updated. Top: Max. This would make an induced voltage of (say) 100 mV into 10 V RMS and quite suitable for rectification and conversion to DC. The self inductance is the total flux divided by the current while the mutual inductance is the flux that couples both loops divided by the current. Figure9 shows the TP over the coupling factor k and frequency f for a constant load \(R_L=R={2.4} \ {\mathrm{k}\Omega }\) with a series-compensated primary and parallel-compensated secondary. Identif. PTE over the coupling factor k. Bottom: Corresponding load resistance \(R_L\), PTE over the coupling factor k and resistance R for an example scenario with constant frequency \(f_0={13.56} \ \mathrm{MHz}\), This holds for all derivations in what follows so that the differentiation between these two cases will not be repeated every time. From (38), three different reflection coefficients can then be derived for the carrier and two sideband signals: The overall reflected wave at port 1 and port 2 can now be determined using (27) and (28), respectively. In the batteryless mode, an NFC-enabled device harvests energy from incoming RF emission (from a reader) to power the sensor interface and RF transmission. \end{aligned}$$, $$\begin{aligned} \begin{aligned} s_i(t)=r_L(t) = \frac{r_{L1} + r_{L2}}{2} + \frac{2}{\pi }(r_{L1} - r_{L2}) \left( \sin (\omega _i t) + \frac{1}{3}\sin (3\omega _i t) + \frac{1}{5}\sin (5\omega _i t) + \cdots \right) . However this is not a principle associated with resonant tuning - it's just a convenience for the designer. You, Y.Y. How to divide the contour in three parts with the same arclength? Tang, Document Analysis and Recognition with Wavelet and Fractal Theories (The World Scientific Publishing Co, Singapore, 2012), J.M. There, the matching capacitor on the secondary side is always directly related to the secondary inductance, regardless of whether it is applied in series or in parallel: \(\omega _0 L_2 = \frac{1}{\omega _0 C_{2s}}= \frac{1}{\omega _0 C_{2p}}\). 56, 18011812 (2009), C.-S. Wang, O.H. In addition to these images, I have seen that the function of these circles is to match the impedance, I would appreciate your help. Moreover, further parameters for optimizing the TP using series matching at the primary and parallel matching at the secondary side are: \(k=0.1\), \(C_{1s}={46}\ {\mathrm{pF}}\), \(C_{2p}={68}\ \mathrm{pF}\), \(R_L={2.4} \ {\mathrm{k}\Omega }\) and \(R_{\rm mod}={50}\ {\Omega }\). Safety standards and guidelines do exist in most countries for electromagnetic field exposures (e.g. 909915, 2002. Topics Power Electron. If matching on the primary side is not sufficient, additional means can be added in order to match the overall impedance seen at port 1 to the source impedance \(R_0\), but then the closed-form expression in (24) does not apply. "When the transmitting coil and receiving coils resonate at 6.78 MHz, the power transfer efficiency is maximized," explains Kuo. IEEE Trans. mean? [5] As a result, the maximum voltage is generated on the secondary coil due to the increase of the mutual flux, and the copper loss of the primary coil is reduced, the heat generation is reduced, and the efficiency is relatively improved. An IPT implementation uses tightly coupled coils with typical coupling factors k m > 0.3 , unlike MRC systems with k m r c < 0.1 . With a data rate of, for example, 106 kbit/s and binary modulation in an RFID system, \(B=106\) kHz would be required. \end{aligned} \end{aligned}$$, $$\begin{aligned} P_{12} = |I_2|^2 (R_2+R)= |I_1|^2 \frac{\omega ^2 M^2 (R_2+R)}{(R_2 + R)^2 +(\omega L_2 + X)^2}, \end{aligned}$$, $$\begin{aligned} \begin{aligned} Q_{12}&=|I_1|^2 \omega (L_1-M) + |I_2|^2 (L_2-M) + |I_1+I_2|^2 \omega M \\&= |I_1|^2 \left( \omega L_1 + \mathfrak {I}\left\{ \frac{j\omega M(j\omega (L_2-M)+R_2+R+jX)}{j\omega L_2 + R_2 + R + jX}\right\} \right) - |I_2|^2 X\\&= |I_1|^2 \left( \omega L_1 - \frac{\omega ^2 M^2(\omega L_2+2X)}{(R_2+R)^2 +(\omega L_2 + X)^2}\right) . In 1894 Nikola Tesla used resonant inductive coupling, also known as "electro-dynamic induction" to wirelessly light up phosphorescent and incandescent lamps at the 35 South Fifth Avenue laboratory, and later at the 46 E. Houston Street laboratory in New York City. That is because the single turn coil and the multiturn coil act like a step up transformer and a low impedance driving circuit can make a multiturn coil resonant at a much higher voltage. Lett. This oscillation will die away at a rate determined by the gain-bandwidth (Q factor), mainly due to resistive and radiative losses. Depending on the application (tightly or loosely coupled systems, coil alignment tolerances, etc. While the early systems used a resonant receiver coil, later systems[16] implemented resonant transmitter coils as well. [10]However, this type of system radiates most of its energy into empty space, unlike modern wireless power systems which waste very little energy. [37] When the system is not in the resonance state, this leads to the open-circuit voltage appearing at the secondary being less than predicted by the turns ratio of the coils. Using electromagnetic field theory, \(L_1\), \(L_2\), M and, thus, k can be determined analytically [26, 27]. Depending on the distance between the transmit and receive coils, only a fraction of the magnetic flux generated by the transmitter coil penetrates the receiver coil and contributes to the power transmission. Section4 describes the results by using scattering parameters. CD carried out this work and wrote the manuscript. The subcarrier frequency varies within \(f_i=f_0/16 \pm f_0/32\), Voltage at port 1 using SPICE simulation. Infographic: Inductive VS Resonant Charging - Electrical Engineering IEEE Trans. ), resonant or non-resonant inductive coupling is applied. Low, R.A. Chinga, R. Tseng, J. Lin, Design and test of a high-power high-efficiency loosely coupled planar wireless power transfer system. For example, Morse or Morlet wavelets [22] would provide frequency information with additional resolution in time. \end{aligned}$$, $$\begin{aligned} R= & {} \frac{R_L}{(\omega C_{2p}R_L)^2 +1}, \quad \quad X = \frac{- \omega C_{2p}R_L^2}{(\omega C_{2p}R_L)^2 +1}, \end{aligned}$$, $$\begin{aligned} R_L= & {} R+\frac{1}{(\omega C_{2s})^2R}, \quad \quad \quad \omega C_{2p}=\frac{-X}{R^2 +X^2}. Unified Theory of Electromagnetic Induction and Magnetic Resonant Coupling The resulting coupling factor over distance d is depicted for \(\rho _1=\rho _2={2.5}\,\mathrm{cm}\), \(N_1=N_2=1\) and \(r_0={0.1}\,\mathrm{mm}\) in Fig.
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