Vector control of current source inverter-fed axial-flux permanent magnet motors with space vector pulse width modulation

This paper presents the vector control design of an axial-flux permanent magnet motor (AFPM) driven by a current source inverter (CSI), which is considered as having many advantages over the voltage source inverter. The control system consists of a 2-DOF speed controller, a multi-loop current controller, and an SVPWM modulation block, which can offer a faster dynamic response, an instantaneous adjustment of the modulation index, and a precise control of the ac motor current magnitude and phase. To evaluate the effectiveness of the proposed control system, computer simulation in PSIM were performed. The speed response of the proposed 2-DOF controller can quickly track the step speed command and reach the steady state even if the load torque is suddenly added to the system.

I. Introduction

In recent years, axial-flux permanent magnet (AFPM) motors as shown in Fig. 1 have been received more attention due to their high efficient, compact construction, and high torque density. They have been utilized in a wide range of applications such as electrical vehicles (EV), flywheel energy storage systems (FESS), and wind-turbine energy generation systems (WEGS) [1]–[3]. Most of the such applications require smooth motor running in order to avoid vibration and acoustic noise mainly due to the cogging torque ripple, which is considered as a periodic position-dependent disturbance produced by the magnet attraction between the rotor mounted permanent magnets and the stator [4]. Thus, it is very important to design a high performance AFPM motor drive to cope with the above problems.