| 1. |
- Falk Olson, Gustaf, 1992-, et al.
(author)
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Enabling Variable Phase-Pole Drives with the Harmonic Plane Decomposition
- 2024
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 12, s. 40049-40063
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Journal article (peer-reviewed)abstract
- Magnet-free variable phase-pole machines are competitive alternatives in electric vehicles where torque-speed operating region, reliability, cost, and energy efficiency are key metrics. However, their modeling and control have so far relied on existing fixed-phase and pole-symmetrical models, limiting their drive capabilities especially when switching the number of poles on the fly. This paper establishes the harmonic plane decomposition theory as a space-discrete Fourier transformation interpretation of the Clarke transformation, decomposing all pole-pair fields into a fixed number of orthogonal subspaces with invariant parameters. The model remains unaltered for all phase-pole configurations, guaranteeing continuity even under phase-pole transitions. Relations of the state and input space vectors, and model parameters to those of the vector space decomposition theory used for multiphase machines are established via the use of the complex winding factor. Experiments confirm the modeling theory and demonstrate its practical usefulness by performing a field-oriented-controlled phase-pole transition. Non-trivial configurations with more than one slot/pole/phase and a fractional phase number are also demonstrated.
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| 2. |
- Falk Olson, Gustaf, 1992-, et al.
(author)
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Harmonic Plane Decomposition : An Extension of the Vector-Space Decomposition - Part II
- 2020
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In: Proceedings of The 46th Annual Conference of the IEEE Industrial Electronics Society, IECON 2020. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 991-996
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Conference paper (peer-reviewed)abstract
- In this paper the harmonic plane decomposition from part I is completed. Multiphase electrical machines with independently controlled stator coils benefit from a fixed amount of current controllers and unified models. In part I, the foundation for such models was laid. This paper shows that the choice of the base case has to fulfill certain criteria to properly represent vector-space quantities. More specifically, phase-pole configurations with an even number of pole pairs need adapted base cases with reduced rank as compared to the odd base case. Continuous modeling and control requires retention of the dimensionality of Clarke matrices. A different number of stator and rotor slots can lead to aliasing in the transformation, when keeping the dimension consistent. Therefore, a specific Clarke transformation for rotor quantities based on the developed theory is elaborated. Finally, it is demonstrated how the harmonic plane decomposition can be used to model each harmonic plane of an arbitrary phase-pole configuration with conventional machine equivalent circuits, e.g. the T-equivalent or inverse-Γ models.
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| 3. |
- Falk Olson, Gustaf, 1992-, et al.
(author)
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Parameter Estimation of Multiphase Machines Applicable to Variable Phase-Pole Machines
- 2023
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In: IEEE transactions on energy conversion. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8969 .- 1558-0059. ; 38:4, s. 2822-2831
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Journal article (peer-reviewed)abstract
- Variable phase-pole machines are envisioned in applications requiring a large torque-speed operating area. The control of these machines relies on accurate models and parameters but research on their parameter identification is scarce. This paper presents an offline parameter-identification method for variable phase-pole machines adopting a harmonic-plane decomposition model. The method employs standard tests with single-frequency three-phase excitation in multiple pole configurations and uses the results to minimize a constrained, regularized weighted least-squares problem. It relies on identifying a set of parameters common to all phase-pole configurations and transforming them into the adopted model. Good agreement is exhibited when comparing experimental results to an analytical harmonic-plane decomposition model using the inferred parameters. Steady-state, as well as pole transitions, are compared. The paper emphasizes the importance of performing measurements in multiple pole configurations and weighing these measurements appropriately to render an accurate set of parameters.
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| 4. |
- Haq, Omer Ikram ul, et al.
(author)
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Generalized Harmonic Injection Strategy for Multiphase Induction Machine Control
- 2024
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In: IEEE transactions on energy conversion. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8969 .- 1558-0059. ; 39:2, s. 1245-1254
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Journal article (peer-reviewed)abstract
- A multiphase induction machine model using vector space decomposition provides insights into many space harmonics through decoupled reference frames. These decoupled reference frames host specific space vectors related to particular space harmonics. Based on the physical winding configuration, these vector spaces can be excited independently and simultaneously for the production of torque. However, this approach may result in beat oscillations due to interference between excited vector spaces if proper synchronization of vector spaces is not maintained. This paper describes this phenomenon through experimental tests. Furthermore, a solution eliminating the beat oscillations is proposed while optimizing the stator current or rotor flux linkage peaks. The effectiveness of the solution is experimentally verified on a 9-phase induction machine.
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| 5. |
- Wu, Yixuan, 1993-, et al.
(author)
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Detection of Multiple Open Faults in Variable Phase-Pole Machines based on Harmonic Plane Decomposition
- 2023
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In: 2023 IEEE 14th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED). - : Institute of Electrical and Electronics Engineers (IEEE).
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Conference paper (peer-reviewed)abstract
- Multiphase electrical machine are inherently truefault tolerant, which is a key difference as compared to conventionalthree-phase machines. The subgroup of variable phase-polemachines have the ability to change phase-pole configurationsonly through current control. Due to the higher availabilityand simpler construction, three-phase voltage source invertersmodules are often used for multiphase electrical machines.While many approaches exist for one single open-phase fault,this paper proposes an open-fault detection method capable todetect the failure of an entire three-phase module for variablephase-pole machines. It is an extension to the harmonic-planedecompositionfault detection analyzing the instantaneous spaceharmonic content of the current distribution. Simulation resultsdemonstrate the feasibility of the approach.
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| 6. |
- Wu, Yixuan, 1993-, et al.
(author)
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Fault Detection in Variable Phase-Pole Machines based on Harmonic Plane Decomposition
- 2022
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In: Proceedings 48<sup>th</sup> Annual Conference of the Industrial Electronics Society, IECON 2022. - : Institute of Electrical and Electronics Engineers (IEEE).
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Conference paper (peer-reviewed)abstract
- Multiphase electrical machines have the inherentadvantage of fault tolerance as compared to conventional threephasemachines. A special category of multiphase electricalmachines are variable phase-pole machines, which allow a changebetween phase-pole configurations without hardware reconfiguration,but merely through current control. This paper proposesan open-fault detection method for variable phase-pole machines; fast, non-invasive, parameter- and operation-independent. Themethod analyzes the space harmonics of the current distributionusing the harmonic plane decomposition theory, which isalready used to perform a seamless switch between phase-poleconfigurations. Simulation results demonstrate the feasibility ofthe approach.
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| 7. |
- Wu, Yixuan, 1993-, et al.
(author)
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FEM-based Parameter Estimation for a Variable Phase-Pole Induction Machine
- 2021
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In: The 23rd European Conference on Power Electronics and Applications (EPE2021). - : Institute of Electrical and Electronics Engineers Inc..
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Conference paper (peer-reviewed)abstract
- In this paper, lumped parameters for a variable phase-pole induction machine with wound independently controlled stator coils are computed using finite-element simulations. Differently from finite-element simulations of conventional electrical machines, this solution uses a per-solenoid approach.
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| 8. |
- Wu, Yixuan, 1993-, et al.
(author)
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Harmonic Plane Decomposition: An Extension ofthe Vector-Space Decomposition - Part I
- 2020
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In: Proceedings of the 46th Annual Conference of the IEEE Industrial Electronics Society IECON 2020.
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Conference paper (peer-reviewed)abstract
- In this first paper of a two-part series, the harmonicplane decomposition is introduced, which is an extension of the vector-space decomposition. In multiphase electrical machines with variable phase-pole configurations, the vector-space decomposition leads to a varying numbers of vector spaces when changing the configuration. Consequently, the model and current control become discontinuous. The method in this paper is based on samples of each single slot currents, similarly to a discrete Fourier transformation in the space domain that accounts for the winding configuration. It unifies the Clarke transformation for all possible phase-pole configurations such that a fixed number of orthogonal harmonic planes are created, which facilitates the current control during reconfigurations. The presented method is not only limited to the modeling of multiphase electrical machines but all kinds of existing machines can be modeled. In the second part of this series, the harmonic plane decomposition will be completed for all types of machine configurations.
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| 9. |
- Wu, Yixuan, 1993-, et al.
(author)
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Open Fault Detection in Variable Phase-Pole Machines based on Harmonic Plane Decomposition
- 2024
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In: IEEE transactions on power electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8993 .- 1941-0107. ; 39:4, s. 4557-4566
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Journal article (peer-reviewed)abstract
- Multiphase electrical machines are inherently fault tolerant due to the higher number of phases. An important step in achieving a fault tolerant control is the ability to detect and identify the fault. In variable phase-pole drives, which are a class of multiphase machines that change the number of pole pairs during real-time operation, there are further unexplored possibilities. Based on the harmonic plane decomposition theory for variable phase-pole machines, a fault detection and identification algorithm is proposed, which analyzes the spatial harmonics of the current distribution. The fault detection is fast, operation independent, non-invasive, parameter-insensitive, and computationally simple. Experimental tests validate the proposed method.
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| 10. |
- Wu, Yixuan, 1993-, et al.
(author)
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Open-Phase Fault Tolerant Pole Transition Control of an Asynchronous Variable-Pole Machine Using Harmonic Plane Decomposition
- 2024
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In: IEEE Journal of Emerging and Selected Topics in Power Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 2168-6777 .- 2168-6785. ; , s. 1-1
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Journal article (peer-reviewed)abstract
- Automotive applications are revisiting the use of induction machines as magnet-free propulsive solutions due to theirintrinsic robustness and reliability. Special multiphase configurations are under investigation to reduce the losses further andfulfill the stringent energy-efficiency and compactness requirements of the automotive industry. One of these configurations isknown as variable-pole machines, which allows the number ofmagnetic pole pairs to change on the fly. These machines canstretch the torque-speed operating region, exploit the maximumtorque capability, and exhibit competitive efficiency. Althoughfault tolerance has been widely explored for multiphase machines,the same cannot be said for variable-pole machines because,until recently, complete models to describe their dynamics under any condition, including magnetic pole changing and faultoccurrences, were unavailable. This paper presents a post-faultcontrol strategy for variable-pole machines with an open-phasefault, which can operate during pole changing and addressesthe issue of fault-tolerant operation. The effectiveness of thecontrol system is verified by experimental tests carried out withan eighteen-phase variable-pole induction machine prototype.
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