Wireless power transfer (WPT) has drawn more and more attention and has many applications, such as wireless electric vehicle charging systems, which require high power, high efficiency, and high power factor. In this paper, a single-stage WPT resonant converter with bridgeless boost power-factor-correction (PFC) rectifier is proposed to improve efficiency and power quality of line input, and reduce production cost and complexity for high-power WPT system. The bridgeless single-stage topology is creatively proposed to apply in WPT system, which is much more advantageous than conventional two-stage WPT converter with individual boost PFC stage.

High step-down dc/dc converters with high efficiency and high power density are widely used in data centers, dc distribution grids and hybrid electric vehicles. In this article, a new resonant switched capacitor converter is proposed, which can not only realize high step-down conversion, but also operate in multiple-modes to achieve various voltage ratios. The duty cycle can be allocated to one-half and one-third, enabling the converter to operate in double-mode and triple-mode accordingly. In addition, the state of the basic resonant cell can be switched between series and parallel, which enriches the operating modes, and thus allowing the converter to achieve different voltage ratios. Furthermore, the principle and strategy of switching between operating modes with different voltage ratios and switching between operating modes with same voltage ratio are presented. With the mode switching strategy, this converter can operate in the optimal mode over the wide voltage range and the full load range, thus achieves high efficiency over the full operating range. Finally, five operating modes are selected to verify the feasibility and the correctness of the theoretical analysis

When the permanent magnet synchronous motor (PMSM) operates at low carrier ratio, the decoupling capability and dynamic performance of the proportional-integral (PI) controller are limited by the digitization delay. In this paper, a deadbeat PI controller is proposed by modified the feedforward. With the modified feedforward, the open-loop transfer function can eliminate imaginary components. Thereby the full decoupling of $d$ and $q$ is realized. At the same time, the controller also has full control over the location of the closed-loop poles, indicating that it can have a deadbeat response for the command tracking. For the disturbance rejection, the controller allows us to select the speed with which the controller can cancel the effect of a disturbance. Further considering that the motor parameters are inaccurate, by designing the controller coefficients with the maximum value of the closed-loop poles, the current-loop can ensure the dynamic performance and harmonic suppression ability. Finally, the effectiveness of the proposed controller is verified by the simulations and experiments.

Three-phase Z-source inverters provide a solution of voltage boosting by a single-stage topology. They are also capable of bidirectional operation as rectifiers, thus have great potential for applications in the field of transportation electrification such as vehicle-to-grid (V2G) chargers. In this article, three new modulation schemes for three-phase Z-source converters are proposed and investigated. The best performed one is further developed to a closed-loop proportional-integral (PI) control method. Although the voltage conversion ratio is flexible, the output voltage total harmonics distortion (THD) is below 3% within the voltage ratio range 0.5-2.5. The effectiveness of the proposed method has been fully validated in MATLAB/Simulink simulations and RT-Lab hardware-in-loop (HIL) experiments based on the real-time simulator OPAL-RT OP4510. Compared to existing control methods, the proposed one performs better with reduced harmonics, flexible voltage gain, and simpler control algorithm.