| Author: | Wang, Weiyu |
| Title: | Position sensorless drive for DC-excited vernier reluctance machine |
| Advisors: | Niu, Shuangxia (EEE) |
| Degree: | Ph.D. |
| Year: | 2023 |
| Subject: | Reluctance motors Electronic control Electric machinery -- Design and construction Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Electrical and Electronic Engineering |
| Pages: | 153 pages : color illustrations |
| Language: | English |
| Abstract: | DC-excited Vernier reluctance machine (DC-VRM) using a 12-slot/10-pole-pair design, exhibits the advantages of small torque ripple and low cogging torque due to the inherent complementary characteristic. Developing advanced position sensorless drive methods can further promote its application in the safety-critical system. For the studied 12/10 DC-VRM, the saliency annihilation phenomenon in the armature winding self-inductance is analyzed through Fourier analysis and the odd-order harmonics in self-inductance are canceled. Then, reconstructing saliency method is investigated by splitting a phase winding into two sub-phase coils and using parallel H-bridge converters to achieve a position sensorless drive. Comparative analysis and optimization of pulse injection sensorless drive methods are conducted, and a novel vertical-axis synchronous pulse injection method is proposed. The key is to inject detection pulses into stator side vertical-axis phases simultaneously, thus reducing the detection time and improving the torque generation. To further improve position sensorless drive performance and power converter universality, the machine saliency is reconstructed by using dual-three-phase inverters drive topology. The released series inductance model with mutual inductance coupling is established through a piecewise function, and an accurate position estimation method without finite element analysis or complex measurements is introduced. Moreover, by further analyzing the linearity of series inductance, the full-cycle inductance high-linearity range is composed of dual-inverter complementary features, thereby the position estimation accuracy can be guaranteed. Through this feature, a predictive position-based pulse injection method for a position sensorless drive is proposed to improve acceleration performance with detection time reduction. Based on the predictive position, the detection pulses are only injected into one inverter whose corresponding phases are located at the inductance high-linearity range, thus decreasing the detection time, and improving the startup performance. To further reduce the cost of the power converters, the position sensorless drive method is developed in the three-phase inverter. By revealing the saliency enhancement effect in mutual inductance, a novel field and armature winding synchronous pulse injection method is proposed. The key is to inject detection pulses into both field and armature windings with the same sequence and pulse width to detect the mutual inductance between them. Then, an optimized virtual inductance-based position estimation method is presented to estimate the position and strengthen the fault-tolerant ability. Moreover, the potential magnetic saturation influence on position estimation caused by superimposed detection currents is avoided with the reverse pulse injection in the field winding. To further improve the system load capacity, a novel saturated inductance differential-based saliency extraction position estimation and sensorless startup method is proposed. By exploring the armature winding saturated differential inductance characteristics during field excitation, the inductance saliency is extracted from the different saturation degrees in the two sub-phase coils. Moreover, through reduced order inductance modeling, a linear inductance characteristic can be guaranteed for reliable position estimation. Consequently, the inductance modeling effort and the required memory size for data storage can be effectively reduced. The proposed method can cover the heavy load condition and guarantee system reliability simultaneously. The feasibility of the proposed methods is verified by theoretical analysis and experiments. |
| Rights: | All rights reserved |
| Access: | open access |
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