Wireless DC Motor Drives with Selectability and Controllability

Abstract

This paper proposes and implements the concept of wireless DC motor drives, which can achieve the abilities of selective driving and controllable speed. Due to different resonant frequencies of the multiple energy receivers of the associated DC motor drives, the transmitter can be purposely tuned to the specified resonant frequency which matches with the specified receiver, hence driving the specified motor selectively. In the meantime, the burst fire control is used to regulate the operating speed of the motor working at the resonant frequency, hence retaining the maximum power transmission efficiency. Both finite element analysis and experimentation are given to verify the validity of the proposed wireless DC motor drive system. For exemplification, three different resonant frequencies, namely 60 kHz, 100 kHz and 140 kHz, are selected to energize three DC motors. Under the burst fire control method, the speed of each motor can be regulated separately and the wireless power transfer (WPT) system can achieve the measured power transmission efficiency of about 60%.

Time-Sharing Control Strategy for Multiple-Receiver Wireless Power Transfer Systems

“…Furthermore, the duty cycle D i ' is updated to D i " in Equation (26) to ensure that the updated duty cycle satisfies Equation (23). The function g(x) is defined such that when the sum of the D i is less than 1, the D i ' that satisfies max D i N f − D i N f is previously compensated with Equation (23) until the sum of D i " satisfies Equation 23.…”

“…Other methods to cancel the cross-coupling effect are proposed for each receiver to operate on different frequencies or set each receiver to turn on in different time sequences. Due to the different resonant frequencies of each receiver, the transmitter is manipulated to transfer the specified resonant frequency to activate specified receiver in Jiang et al [26]. Three different resonant frequencies, namely 60 kHz, 100 kHz, and 140 kHz, are chosen to deliver power to three DC motors with an efficiency of about 60%.…”

An Overview of Resonant Circuits for Wireless Power Transfer

“…After the targeted receiver is predetermined with a certain resonant frequency, the primary circuit calculates the corresponding capacitance to suit the resonant frequency of the targeted receiver. Thus, the targeted receiver has the strongest coupling with the primary to pick up the energy [76]. …”

Continuously Variable-Frequency Energy-Encrypted Wireless Power Transfer

“…This wireless energy-accessing pattern is gradually improving our conventional plug-in charging pattern and meanwhile alleviating the limitations of current battery techniques. As one of most epoch-making technologies, the WPT shows great talents and potentials in various industrial applications and interdisciplinary areas, such as domestic appliances or medical electronics [5][6][7], electric vehicle (EV) wireless charging [8][9][10], wireless motor drive [11,12] and emerging wireless energy security [13,14].…”

“…Although the WPT successfully removes the messy charging wires, it inevitably takes the risks of energy stealing or leakage because of such convenient wireless energy-accessing pattern. Although a selective WPT technology can achieve oriented power transmission to specified receivers among multi-receivers [11,16], the illegal receivers may track and lock the fixed operating frequency to steal the wireless power. Accordingly, to guarantee wireless energy security, the concept of energy encryption was proposed to encrypt the wireless energy as the information encryption does, which ensures that only authorized receivers can successfully decrypt and harvest the encrypted wireless energy [9,13].…”