With the development and construction of urban sewerage systems and underground pipelines, it's very important to realize the power supply and control of in-pipe motors, which can be used for pipeline robots or to discharge floodwater. This paper proposes a harmonic modulated wireless energy and drive signal synchronous transmission technology for the motor in pipelines. The transmitter (Tx) side inverter of the Wireless Power Transfer (WPT) system is used to modulate the second and third harmonic energy, and the corresponding harmonic energy is extracted from the secondary side as a harmonic drive signal to drive the motor inverter directly, thus realizing the direct drive control of the motor on the Tx side. This technology, which eliminates the additional bidirectional communication control module, motor inverter drive circuit, and auxiliary power supply, realizes the power supply and control of the in-pipe motor. By analyzing the modulation and transmission of the second and third harmonic energy, the corresponding modulation and extraction methods of harmonics are given. A 110W prototype is built for experimental verification and the experimental results indicate that the second and third harmonic energy can effectively drive the motor inverter.

The shielding effect of rebar arrays on magnetic fields poses a challenge for inductive power transfer (IPT) systems that power sensors in structural health monitoring systems. In this paper, we propose a method to enhance the maximum output power of IPT systems by reducing the shielding effect of the rebar array. The shielding effect is caused by the magnetic field produced by the induced current in the rebar array. To overcome this, an additional coil is mounted on the rebar to couple with two adjacent rebar loops. By adjusting the capacitance value in series with the additional coil, the equivalent impedance of the rebar loop is changed, altering the phase of the induced current and allowing it to effectively superimpose with the magnetic field produced by the transmitter coil. The equivalent circuit of the system is analyzed based on the dipole coil as the transmitter and receiver coil. Furthermore, a parameter design method of capacitance in series with the additional coil is presented to enable the system to achieve maximum output power capacity. Circuit simulation results verify that this method can increase the maximum output power from 4.3W to 13.5W.

In recent years, electric bicycles (EBs) have drawn widespread attention to save energy. Wireless power transfer (WPT) is a competitive approach to charging EBs due to its convenience and safety. In order to reduce the power conversion stages and make charge systems more compact, single-stage converters (50Hz AC to High-frequency AC) for WPT have been widely studied. However, as the narrow pulse width of the front bridge for PFC, zero voltage switching (ZVS) is difficult to achieve under a wide load range, resulting in low system efficiency and electromagnetic interference. In this paper, an asymmetric modulation method is proposed. By altering the duty cycles, the magnitudes of second and third harmonic currents are manipulated to achieve ZVS under wide load and input ranges, leading to high system efficiency. A 144W prototype is built to verify the feasibility of the proposed method. Experiments verify that the system can achieve ZVS within 36- 144W power output and 70V-110V voltage RMS input, and the maximum efficiency reaches up to 90.48% (@144W, 110V input and 48V output).

Dynamic wireless power transfer (DWPT) is a promising solution to address electric vehicle range anxiety and to reduce the capacity and the cost of the on-board batteries. In the traditional DWPT system, the mutual inductances among the transmitters make the design of compensation networks very complex. Besides, the power null phenomenon and the power pulsation phenomenon cause a fluctuating dc output voltage or current on the receiver side. To address these issues, this paper proposes a new magnetic coupler. Unipolar and bipolar coils are laid alternately to form segmented transmitters, which are turned on or off according to the position of the overhead receiver coil. LCC compensations, whose inputs are connected in parallel to a common inverter for cost reduction, are adopted. At the receiver side, unipolar and bipolar coils are overlapped in the same plate in order to effectively smooth out the mutual inductance variations and, hence, reduce the output voltage or current fluctuations. Also, a configurable resonant circuit is designed on the receiver side to achieve constant voltage charging and constant current charging. Moreover, an optimization design by using finite-element analysis software Maxwell is developed to choose the best turns of the receiver coil to further improve the output quality. A laboratory prototype with 4-A charging current and 96-V charging voltage, using 85 kHz operation frequency, is constructed to verify the proposed DWPT system. The experimental results show that constant and stable output voltage and current can be achieved with only ±2% fluctuation, and the overall efficiency is 90.37%.