This paper is to present a new effective sandwiched wireless power transfer (WPT) system, which is adopted to recharge the battery of a micro medical robotics for cardiac pacemaker. The key of the design is to use the distinct sandwiched topology in both the transmitter and receiver coils, which operating frequency of 160 kHz is significantly lower than the reported WPT system up to mega Hz. Furthermore, the implantable receiver adopts the bilateral coil design, which can harness more power within a limited size. Meanwhile, with the sandwiched transmitting coils, the proposed design achieves the high feasibility and flexibility of the controllable distance for different kind of micro medical robotics in patients. As a result, the proposed system can provide the power as high as 5 W and the transmission efficiency up to 88%. Finally, the corresponding theoretical analysis, simulation and experimentation are carried out to prove the validity of the proposed sandwiched medical WPT system for the implantable device in patient body.

With ever-increasing concerns for the safety and convenience of the power supply, there is a fast growing interest in wireless power transfer (WPT) for industrial devices, consumer electronics, and electric vehicles (EVs). As the resonant circuit is one of the cores of both the near-field and far-field WPT systems, it is a pressing need for researchers to develop a high-efficiency high-frequency resonant circuit, especially for the mid-range near-field WPT system. In this paper, an overview of resonant circuits for the near-field WPT system is presented, with emphasis on the non-resonant converters with a resonant tank and resonant inverters with a resonant tank as well as compensation networks and selective resonant circuits. Moreover, some key issues including the zero-voltage switching, zero-voltage derivative switching and total harmonic distortion are addressed. With the increasing usage of wireless charging for EVs, bidirectional resonant inverters for WPT based vehicle-to-grid systems are elaborated.

In the permanent magnet synchronous motor speed regulation system, the dynamic performance of the conventional active disturbance rejection control (ADRC) system will be deteriorated by using a low bandwidth speed filter. To solve this problem, two ADRC controllers considering the speed measurement noise are proposed in this article. One proposed ADRC system is based on the extended state observer (ESO), the other proposed ADRC system is based on phase-locking loop observer (PLLO). In the proposed two ADRC systems, an integrator is employed as the speed filter so that the measured position can be directly used for observing the speed and disturbance without speed calculation. Meanwhile, by using an integrator as the speed filter, the dynamic performance of the proposed ESO-based ADRC system is not affected since it is independent of the speed filter, and the proposed PLLO-based ADRC system has a better rejection ability for the low-frequency disturbance. Experimental results validate the proposed methods.

Emerging topics such asenvironmental protection and energy utilization have pushed research and development of electric vehicles and hybrid electricvehicles (EVs/HEVs). In the last few decades, numerous technologies have been developed for EV/HEVimportance. In this article, key research topics in the area of EVs/HEVs, namely electric machines, electrochemical energy sources, wireless charging infrastructure, and latest EV/HEV models are covered. This paper aims to consolidate the key emerging technologies in this field and provide the readers a blueprint to begin their own journeys.

In this paper, a new class of wireless secondary converterless switched reluctance motor (WSC-SRM) drives is proposed and implemented. The key is to develop a unique wireless power transfer (WPT) system to directly drive the SRM without involving any power converter at the motor side. This is particularly essential to enable the WSC-SRM working in isolated environment with maintenance free. Based on selective WPT, the phase windings of the SRM can be properly energized by the same transmitter which adopts a newly developed compound structure. Meanwhile, signal duty ratio control of the transmitter is employed to achieve the speed control of the WSC-SRM. Both simulation and experimental results are given to validate the feasibility of the proposed system. For exemplification, a prototype is designed and constructed, which can provide WPT up to 150 mm transmission distance and achieve up to 72.8% transmission efficiency.

This paper proposes and implements a novel quasi-omnidirectional dynamic wireless power transfer (WPT) system using double 3-D coils for drone applications. In the traditional omnidirectional WPT system, the receiver direction is always facing the 3-D transmitter center to maximally pick up the magnetic flux. However, the on-drone receiver normally proceeds horizontal or vertical movements so that it is unable to fully utilize the magnetic flux and result in serious magnetic flux leakage. Thus, by newly proposing the 3-D intermediate coil and artfully aligning specific quadrant of double 3-D coils to the center of the flying area, the proposed WPT system can flexibly and efficiently power the drone in the specific space. Moreover, only one single power source is needed to drive the transmitter coil without using the sophisticated current phase control. Therefore, the proposed system can simultaneously achieve both quasi-omnidirectional WPT and dynamic WPT for the drone so that its flying time can be significantly extended. The theoretical, simulated, and experimental results are given to validate the feasibility of the proposed WPT system.