Analysis and Control of Complementary Magnetic-Geared Dual-Rotor Motor

Abstract

 -Magnetic-geared dual-rotor motor (MGDRM) is receiving increasing attention due to its advantages as a kind of pure electrical power split device for the series-parallel hybrid powertrain. This paper performs a systematic study on the analysis and control model of the complementary MGDRM. The principle of the complementary MGDRM is illustrated in detail. The torque production and flux-weakening ability of the complementary MGDRM are analyzed by the analytical method and a revised 2D FEA method. The field-oriented-control (FOC) method for the MGDRM is firstly realized in this paper. On the basis of the FOC model, the torque production and flux-weakening control in a wide speed range can be implemented. The static and dynamic performances of the MGDRM are analyzed based on the FEA and simulation models. The experiments on a prototype of the complementary MGDRM are carried out to validate the study.Index Terms-Magnetic-geared dual-rotor motor, permanent magnet motor, power split device, hybrid electric vehicle, field-oriented-control, complementary structure.

Motion Control and Performance Evaluation of a Magnetic-Geared Dual-Rotor Motor in Hybrid Powertrain

“…As the work in [19], the outer airgap field is oriented for implementing the field-oriented control (FOC). However, because the angular position of the magnetic field is determined by the relative angular position between the inner and outer rotors, the d-and q-axis of the outer airgap field is not explicit.…”

“…In the figure, two resolvers are used to measure the angular positions of the two rotors, θ ir and θ or . By the field orienting method [19], the angular position of the fundamental field component θ w can be calculated. With the error between the desired speed n * ir and the real speed n ir of inner rotor, the q-axis current command is generated by a PI regulator.…”

“…A simple method is to revise the model by the torque results of FEA, which can precisely calculate the torque with considering the saturation and couple effect. According to the torque relationships [19], the inner and outer rotor torques (T ir and T or ) can be calculated and implemented on the shafts by the torque actuator elements of Matlab/Simulink.…”

“…The step screwing rotors were practiced by dividing the rotors into three segments. And then, the general design method of the complementary structure has been investigated in [19] from the perspective of airgap field harmonics. Dimension equation of the MGDRM was established and used for motor design.…”

“…Three phase distributed windings with 36 slots /6 poles are adopted. The problem of asymmetrical magnetic circuit [19] also exists in this original motor configuration, so a new 2-segment complementary structure is developed to suppress the torque ripple. The inner and outer rotors are divided into two segments shifted by Δθ ir = 6° and Δθ or = 8.57°, respectively, as shown in Fig.…”