Self-Sensing Control of Highly Efficient Self-Bearing Motor for Artificial Heart

研究了自轴承电机作为人工心脏作动器的应用。应用于人工心脏执行器时，要求系统小型化、高效率、低功耗、低发热量。此外，转子和定子之间的正弦磁链分布也有利于抑制狗动转矩，实现稳定的悬浮控制。自轴承电机是一种主动控制系统，需要一定类型的传感器。因此，自传感技术是实现系统小型化的重要技术。本课题提出了一种基于差动变压器原理的内部永磁式自轴承电机自感知控制技术。在IPM型电机中，由于凸极的特性，主磁通（d轴）定向磁导率与正交（q轴）定向磁导率不同。当IPM型转子旋转时，驱动线圈与控制线圈之间的互感不仅随径向位移而变化，而且随其旋转角度而变化。这意味着不能简单地从互感中独立检测径向位移信息。首先，采用有限元法对转子内部永磁体的分布进行了磁场分析。根据分析结果，设计并制造了样机IPM自轴承电机。其次，提出了采用全波整流的检测方法来获得更稳定的差分输出，并提出了新的补偿方法来线性化自感知信号的非线性特性。最后，为了验证所提出的补偿方法，制作了一种内部永磁式主动磁轴承并进行了测试。结果表明，该系统在静态实验中无干扰，具有良好的线性特性，可实现高达6000 rpm的稳定旋转控制。结果表明，该方法对IPM型自轴承电机的自感知控制具有很高的可能性和可行性。现在我们计划改进线性化补偿，并将其应用于IPM型自轴承电机，以开发可用的作动器作为人工心脏。少

Application of self-bearing motor as an actuator for an artificial heart was considered. When it is applied to an artificial heart actuator, miniaturization of the system, high efficiency, low power consumption and low heat generation is required. Moreover, the sinusoidal flux distribution between the rotor and the stator is also preferable to suppress dogging torque and realize stable levitation control Self-bearing motor is an active control system, which requires a certain type of sensor. Therefore, self-sensing is very important technique to realize miniaturization of the system.This project proposed self-sensing control technique based on the principle of differential transformer to the interior permanent magnet (IPM) type self-bearing motor. Main flux (d-axis) directional permeance is different from its orthogonal (q-axis) directional one because of the salient pole property in the IPM type motor. When the IPM type rotor rotates, the mutual inductance between the driving coil and … More the control coil varies with not only radial displacement but also its rotation angle. It means that the radial direction displacement information is not detected simply from the mutual inductance independently.First, Magnetic field analysis using finite element method was done to analyze the allocation of the interior permanent magnets of the rotor. Prototype IPM self-bearing motor was designed and fabricated from the analyzed results.Secondary, new detection method using full-wave rectification was introduced to obtain the more stable differential output and new compensation was also proposed to linearize the nonlinear characteristics of the self-sensing signal.Finally, to confirm the proposed compensation method, an internal PM type active magnetic bearing was made and tested. The result showed no interference and linear characteristics in the static experiment and accomplished stable rotation control up to 6,000rpm.From these results, we confirmed that the proposed method has high possibility and feasibility for self-sensing control of the IPM type self-bearing motor. Now we plan to improve linearized compensation and apply to the IPM type self-bearing motor for development of the available actuator as an artificial heart. Less