Author : Feida Chen (Ph.D.)
Release : 2024
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Kind : eBook
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Book Synopsis Investigation of Voltage-boosting Current Source Inverters for Integrated Motor Drives by : Feida Chen (Ph.D.)
Download or read book Investigation of Voltage-boosting Current Source Inverters for Integrated Motor Drives written by Feida Chen (Ph.D.). This book was released on 2024. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research is to investigate a high-efficiency CSI-based integrated motor drive (IMD) by using voltage boost function and soft-switching technique. First, the commutation processes of the voltage-source inverter (VSI) and current-source inverter (CSI) are analyzed and compared. The impact of the parasitic components in the CSI current commutation loop between the two-phase legs and output capacitors on high-frequency SiC devices' performance is analyzed. Two CSI benchtop prototype units, one with SiC discrete devices and the other with power modules, have been designed and tested, and the performances of the two CSIs are compared. Second, the design of a power-dense CSI-based IMD system using WBG switches for EV traction applications including the IMD structure, power electronics, and cooling system is presented. Attention is devoted to the design of each of the major IMD sub-systems including the dc/dc converter, CSI, passive components, controller, sensors, and the combined liquid/air thermal management system. Both analytical and measured performance results are provided for the prototype IMD system. In addition, an "apples-to-apples" comparison of VSI- and CSI-based motor drive systems with the same performance capabilities is presented. More specifically, sine filters are added to the VSI output terminals to match the CSI performance, and a front-end boost converter is added to the VSI to match the CSI's voltage-boost capability. Third, the voltage and current trajectories of SiC MOSFETs in the switching transition of a CSI-based motor drive system are analyzed in detail and compared with VSI. A high-accuracy loss model of SiC MOSFETs in the CSI is proposed considering the current commutation and parasitic parameters in the current commutation loop. A CSI-based double pulse test is developed to verify the proposed switching transient characteristics and switching loss model. The 3-phase CSI experimental results verified that the proposed power loss model has higher accuracy than the conventional loss model. Fourth, the voltage boosting feature of the CSI is investigated to improve the overall efficiency of the CSI-based motor drive system. The effects of the boost function on the total system losses are described based on the proposed CSI loss model and double pulse test results. In addition, the impacts of the current angle and voltage boost ratio on the CSI efficiency and power factor are investigated, considering the effect of the filter capacitors at the CSI output terminals. A genetic algorithm has been used to optimize the CSI's switching frequency and modulation index to maximize the drive system efficiency under any desired operating condition. The investigation of voltage-boost features is extended to the emerging seven-switch current-source inverter (H7-CSI) to enhance the efficiency of CSI-based motor drive systems. Finally, a novel soft-switching method for CSI is investigated to increase the CSI efficiency and reduce the overshoot issues of the WBG devices. The system configuration, working principle, circuit design, and control schemes are described in detail. The performance of the proposed soft-switching CSI is verified by simulation and experiment. It is shown that the proposed soft-switching circuit can significantly decrease the switching loss and improve efficiency.
