Optimization of spread-spectrum MSK sequences and passive, multi-resonant bandpass rectifiers for wireless power transfer with low electromagnetic interference

Abstract

This paper addresses the concern for both electro magnetic interference (EMI) and human RF exposure in wire less power transfer (WPT). In many applications like medical, portable, and wearable devices, RF exposure is a greater concern, and the unrestricted ISM bands are often not optimal. Outside of the ISM bands, the restrictions on transmitter power are onerous.The computer-aided design of appropriate spread spectrum sequences to drive WPT and the associated bandpass rectifiers is presented. The sequences are optimized for a new four-quadrant inverse class D amplfier using a genetic algorithm. The wireless power is captured by a high order bandpass rectifier that is optimized using a surrogate model to alleviate the computation cost of performing time domain simulations.

Quad-switch push-pull (QSPP) RF amplifier with direct, simultaneous modulation of phase and pulse position for spread-spectrum power applications

“…2 of the distribution of zero durations when the total zero duration is constrained in the optimization. The results are different from that in [34] because of the zero duration constraints and the details of performing such an optimization will be described in a future paper.…”

“…This can also result in a resonant current distortion from the magnetizing current that is dependent on the accumulated voltseconds from the switching pattern. The construction of the switching pattern is described in [34]: the switching pattern is constructed from a dictionary of subsequences each with zero average volt-seconds. By using a cross-coupling capacitor, as in Fig.…”

“…These include frequency modulation [13], [24]- [26], random modulation [27]- [32], and pulse position modulation [33], among others. In [34], the optimization of a spread-spectrum method for wireless power transfer is discussed; this paper presents and discusses the design of an RF amplifier that is particularly suited for this, along with other spread spectrum methods. The amplifier directly modulates both phase and pulse-position simultaneously that is resonant yet produces spread-spectrum power.…”

“…There are several improvements in this paper to the sequence optimization described in [34]. First, the pulse dutycycle is held constant for a given optimization; the pulse dutycycle is defined as the ratio of the time the pulses occupy in a given sequence to the total duration of the sequence (duration at zero, or zero duration, plus duration of pulses).…”

Code Division Multiple Access Wireless Power Transfer for Energy Sharing in Heterogenous Robot Swarms

“…In [17], we presented the first application of CDMA for WPT using half sine voltage pulses encoded as ternary codes. The first demonstration of power exchange using ternary codes was presented in [18]. In [19], receiver topologies were presented for receiving maximum power from these ternary sequences.…”