A new circuit structure for near field wireless power transmission

Abstract

Wireless power transmission using mid-range magnetic resonance has become an important technology in body area sensor systems. Recent researches have used fine-tuned impedance matching for wireless power transmission at fixed distance. However, this method is significantly sensitive to the distance change between two devices since the impedances at both ends must be perfectly matched. Hence, it is a major challenge to achieve efficient wireless power transmission in mobile environment. We propose a new circuit architecture for wireless power transmission in the near field; the Resonator Isolation (RI) structure. Using the RI structure, the wireless power transmission becomes highly robust under mobile environment. In this paper, we present the circuit design of the RI structure and evaluate its performance with the actual systems we constructed.

Random energy charging for reviving sensors in wireless sensor network

“…7(a), the nodes in the REC scheme can receive energy from the WCV only when the residual energy is less than 20% (k = 0.8). We can see that (12) holds for λ 1/sec. Both PEC and TEC schemes converge to the upper limit 0.9.…”

“…The nodes in the REC scheme can receive energy from the WCV when the residual energy is less than 80% (k = 0.2). We can see that (12) still holds for λ 1/sec. The performance of the AEC scheme is not much different from the REC scheme, when the encounter rate is less than 0.03/sec.…”

“…Addition to the resonant coupling method, [12] proposed the RI system that uses an Instantaneous Periodic Delivery (IPD) method to induce energy to the primary resonator. In the IPD method, DC energy is instantly injected into the primary resonator.…”

“…Since the impedance at each end varies with distance between the transmitting and receiving resonators, the efficiency can significantly drop when transmitting energy in a mobile situation. The impedance matching problem can be overcome using the Resonator Isolation (RI) system proposed in [12]. As shown in Fig.…”

Ultra-low power sensor platform with wireless charging system

“…RI system shows high robustness against channel variation since it does not require any accurate impedance matching circuit [10]. Finally, we investigate the power budget of ultra-low power sensor platform which can be recharged by wireless power transfer.…”