Stability and control of inductively coupled power transfer systems

Insights into Dynamic Tuning of Magnetic-Resonant Wireless Power Transfer Receivers Based on Switch-Mode Gyrators

“…On the other hand, Figure 2b depicts the frequency drift by ∆fl as a result of 15% mismatch while it drifts to a higher frequency by ∆fh amount due to −20% mismatch. As a direct result, in order to overcome the pitfall of high-Q receivers, the QRL is normally limited to less than 10 in most systems particularly for high power applications [3]. This, however, is not an adequate choice for low power applications that would demand energy from a distance that extends up to a few times the coil diameter.…”

“…Equation (3) shows that the resonant tank voltage V ac is boosted from the open-circuit induced voltage V oc by a factor that is equal to the quality factor Q RL .…”

“…Magnetic-resonance WPT is considered as an inductive coupling supported by resonance in which the transmitter and receiver are allowed to resonate at a common operating frequency. The resonant inductive coupling WPT is well known due to its superior power transfer capability over an extended range while efficiency is still reasonable [3]. Several compensation techniques have been introduced and studied extensively in the literature starting from the simple connection of series or parallel compensating capacitor [4] up to more advanced topologies such as inductor/capacitor/inductor (LCL) [5] and inductor/capacitor/capacitor (LCC) [6].…”

Dynamic charging using parallel line feeder with hybrid inductive-capacitive coupling and receiver-side load control

“…This structure is highly efficient but complex and costly, because it requires an inverter for powering each coil [2], as well as a fast vehicle sensing to quickly tune the coil, on which the vehicle is passing-by. Systems proposed in [4] and [5] use one elongated feeder to charge the receiver moving within the large feeding area. These systems have lower efficiencies because the receiver picks up only one portion of the electromagnetic field.…”

“…Operating frequency is then raised from below 300 kHz as in [3,4,5] to within the high frequency (HF: 3-30 MHz) band to make further improvements. In [6], for further reduction of system size and cost, an HF generator is used to power an inductively-coupled parallel line feeder.…”