Wireless motor drive (WMD) systems have been developed to address the problems of wire twists and motion limitations. Among various techniques, inductive power transfer (IPT)-based WMD systems have been widely adopted due to their high efficiency and power capacity. This review focuses on the circuit topologies and operating principles of IPT-based WMD systems. Existing WMD systems are categorized into two main architectures: cascaded and integrated structures. In cascaded structures, the IPT converter and the motor drive are implemented as separate stages. In contrast, integrated structures combine IPT and motor drive functions, typically through the use of multiple coils or matrix converters. The paper first examines various cascaded configurations, classified according to the voltage and current characteristics of the IPT output and the motor drive input. A comparative analysis between these topologies is then provided. Subsequently, the paper explores integrated structures, summarizing feasible multi-coil configurations and explaining the multiple frequency operation principle which is essential to such designs. Moreover, the application of matrix converters in WMD systems is reviewed, with a detailed discussion of their modulation strategies. Finally, based on the current state of research, the paper outlines existing challenges and proposes prospective directions for future development in the field.




