The Simplified Multilevel Technology Used in Permanent Magnet Synchronous Motor with Low Inductance

There are many advantages of disc coreless permanent magnet synchronous motor(PMSM). But its defects cannot be ignored. It is difficult to be applied in electrical driving field because of its low inductance. There will be a stringent current and torque ripple when the disc coreless PMSM is driven by a conventional PWM voltage-source inverters(VSI). The reasons of stringent torque and current ripple are analyzed to improve the ripples. The principles of reducing current ripple are given. A simplified multilevel technology is proposed by combining with the technology of multilevel and the concept of vector synthesis. It is based on the 2-level converter with a variable bus voltage circuit. The torque and current ripple of disc coreless PWSM is reduced with the novel control algorithm.