Objective Incorporating permanent magnets into the onboard electromagnets enables the formation of hybrid suspension electromagnets in the permanent magnet electromagnetic hybrid suspension (hereinafter abbreviated as PMEHS) technology. This technology relies on permanent magnets to provide the majority of the levitation force and realizes dynamic adjustment of the levitation force using coil windings. Thereby, it can significantly reduce the energizing current of the electromagnets and cut down their energy consumption and heat generation, showing great developmental potential. To further promote the application of PMEHS technology in urban rail transit, it is necessary to study its current development status and technical challenges of.

Method Relevant researches on PMEHS conducted by domestic and foreign universities and research institutions are reviewed. Taking China, the United States, Japan and other countries with advanced maglev technologies as examples, the R&D and optimal design of hybrid suspension electromagnets are elaborated, and the engineering application status of hybrid suspension technology in urban rail transit is described as well. Based on the analysis of research achievements and current technical status worldwide, the key technical challenges confronted by PMEHS technology are summarized.

Result & Conclusion The United States, Japan and other countries have initiated researches on hybrid suspension technology in an earlier time, but the technology promotion and commercialization are relatively slow, remaining still at the stage of prototype design and experimental research. Through technological optimization, China has developed multiple generations of PMEHS test vehicles with practical engineering application value, stepping into the stage of engineering verification and application. Nevertheless, the introduction of permanent magnets in hybrid suspension can easily lead to increased control difficulty of the suspension system and the magnetic levitation sticking phenomenon, which are the key technical challenges to be solved in the engineering application of PMEHS.