Wireless power and information transmission (WPIT) technology can realize simultaneous wireless transmission of power and information. In this paper, the fundamental component of the triangular current waveform is employed to transfer power, and its third-order harmonic component is selected to transfer information. The Fourier decomposition method is conducted to analyze the triangular current waveform; two equivalent circuit models of the proposed WPIT system are established based on the relationship between the fundamental component and the third-order harmonic component. Harmonic components have an enlargement effect on the deviation of the fundamental frequency; this feature is used to realize the weakly coupled control between the information transmission and the efficiency of wireless power transfer. Based on the proposed harmonic communication method, the transient process and the maximum communication speed of the circuit are discussed. To achieve the high signal-to-noise ratio (SNR) communication, different space positions of the signal receiving winding are compared. Experimental results show that the proposed method provides a new solution for designing the WPIT system.

Compared to traditional simultaneous wireless power and information transfer (SWPIT) technologies, communication technology utilizing the output harmonic component of an inverter as a signal carrier can achieve highperformance signal transmission without affecting power transmission. The SWPIT technology based on phase-shift modulation in inductively coupled power transfer (ICPT) system is proposed in this paper. By changing the phase angle of the inverter, a trapezoidal wave current is generated on the primary coil, and a frequency selection circuit is added in the secondary side to separate the fundamental and harmonic currents. The fundamental component current is used for wireless power transfer while the harmonic current is used to transmit the signal. Firstly, the structure and working principle of SWPIT system based on phase-shift modulation in ICPT system are analyzed. Then, a system equivalent model is established and the reactive power is analyzed in depth. Next, the phase angle variation range is determined by crosstalk analysis. Finally, the correctness and effectiveness of the proposed technology are verified with an experimental platform at 50W. The experimental results demonstrate that the power and information can be transmitted stably with output voltage fluctuation less than 3%, and the signal transmission rate up to 6 kbps.

Traditional predicted core loss models, such as the improved Steinmetz equations, cannot show the whole changing tendency of core losses in different topologies. In this article, a core loss prediction model is presented based on sinusoidal losses. The axis of flux density is divided into a number of slice pairs in a B - P_h plane, and the hysteresis loss density is given in each slice pairs. By summing hysteresis losses associated with the actual swings of flux density in the B - P_h plane, total hysteresis losses can be calculated quantitatively. This empirical approach is available both in calculating hysteresis losses under the centered and noncentered minor hysteresis loops. The effect of duty cycles on the swings of flux density and dc bias are analyzed, and two terms of k _dc ( D ) and k_ΔB ( D ) are identified to show their effects on hysteresis losses. Dynamic eddy current losses are mainly associated with exciting waveforms, which are indicated by introducing a term k_e ( D ). Since the main features of power converters are characterized by three terms, the behaviors of core losses in various topologies can be described adequately. Experimental results from three typical power converters agree with theoretical analyses well.

The trapezoidal current controlled by the phase-shifted modulation is proposed to realize wireless power and information transmission. The fundamental component of the trapezoidal current waveform is used to transfer power, and its harmonic component is selected to transmit information. Fourier decomposition method is conducted to establish the equivalent circuit model of the proposed system. By defining the triangularization rate of the trapezoidal current, quantitative analysis can be gotten to show the relationship of fundamental and harmonic components to different shapes of trapezoidal currents. Compared to the triangular current with the same peak current, the trapezoidal current waveforms can supply higher power. By changing the triangularization rate of the trapezoidal current, a dynamic control method of harmonic components for communication is achieved. Experimental results show that the proposed method can effectively control harmonic components to reduce electromagnetic interference noises, and the impact of communication function on the efficiency of wireless power transfer is extremely weak. Besides, the quasi-decoupling control between load conditions, communication function, and communication speed can be achieved.

This paper proposes a simple and low-cost brightness and color control method for a wireless light emitting diode (LED) system. Since the open circuit voltage of the LED in the secondary side is approximately constant, the average current flowing through the LED reflects the average power received from the proposed wireless power transfer system. The brightness of the LED is adjusted by using a pulse width modulation (PWM) average power control method from the primary side directly. The same inductively coupled channel is utilized to establish a wireless communication channel to control the LED color based on a time-division multiplexing method. A wireless communication protocol is defined, and the worst-case condition for designing the primary PWM modulator identified to avoid the misinterpretation by the secondary demodulator between the power regulation and signal transfer. Experimental results have demonstrated the whole dimming capability of the proposed system with full range duty cycle regulation, and a three digit wireless communication channel developed in this paper can effectively control the selection of eight colors.

Magnetic components in switched-mode power converters usually work under the rectangular voltage excitations with a dc premagnetization; the nonlinear changing characteristics of core losses in the magnetic components are hard to predict. In this paper, the method for predicting core losses in power inductors is introduced. A simplified hysteresis loss model is proposed to explain the well-known empirical characteristics of the hysteresis loss. If the working conditions of the dc bias and flux density are the same, hysteresis losses will keep constant independent with the exciting voltage waveforms, and the values of eddy-current losses will also have the constant mathematics relationships between nonsinusoidal voltage excitations and sinusoidal voltage excitations. The proposed method is very practical since it only takes core loss data under the sinusoidal voltage excitations as inputs rather than relies on any material parameters. Core losses under the different duty cycles and premagnetization levels have been tested; the experimental results verify the correctness of the proposed model.