A unified theory for optimal feedforward torque control of anisotropic synchronous machines

Eldeeb, Hisham; Hackl, Christoph M.; Horlbeck, Lorenz; Kullick, Julian

doi:10.1080/00207179.2017.1338359

Cited by 87 publications

(100 citation statements)

References 43 publications

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“…In order to achieve high efficiency and produce as much energy as possible, the Maximum Torque per Current (MPTC) strategy can be implemented. This strategy is often called Maximum Torque per Ampere (MTPA) but, as explained in [1], the terminology MTPC might be more appropriate.…”

Section: Motivationmentioning

confidence: 99%

“…The idea of MTPC is to minimize the current amplitude for a certain torque, to reduce the copper losses in the stator windings. For this, the generally nonlinear flux linkage has to be known [1,[3][4][5].…”

Section: Motivationmentioning

confidence: 99%

“…The solution for a given torque can also be calculated analytically. A unified theory for optimal feedforward torque control with non-negligible mutual inductance was presented in [1].…”

Section: Maximum Torque Per Current For Linear Flux Linkagesmentioning

confidence: 99%

See 2 more Smart Citations

Experimental Identification of the Optimal Current Vectors for a Permanent-Magnet Synchronous Machine in Wave Energy Converters

Krüner

Hackl

2019

Energies

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This paper investigates efficiency enhancements in Permanent-Magnet Synchronous Machines (PMSMs) used as generators in wave energy converters. A method is presented, which allows experimental identification of the optimal current vectors leading to minimal losses and maximum efficiency. Iron and inverter losses are considered. The proposed identification method is generic and is applicable to any PMSM used as a generator. The obtained results are compared to the well-known Maximum Torque per Current (MTPC) strategy. Two MTPC strategies are investigated: (i) MTPC using linearised flux linkages; and (ii) MTPC using measured, nonlinear flux linkages. For both MTPC strategies, the influence of the Voltage Source Inverter (VSI) is taken into account. All measurements are performed on a simple and cheap industrial-like test bench. All three presented methods lead to increased efficiency. The best efficiency is obtained by the proposed maximum efficiency strategy, where iron and inverter losses are taken into account by proper measurement of the optimal current vectors.

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Section: Motivationmentioning

confidence: 99%

Section: Motivationmentioning

confidence: 99%

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Experimental Identification of the Optimal Current Vectors for a Permanent-Magnet Synchronous Machine in Wave Energy Converters

Krüner

Hackl

2019

Energies

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show abstract

“…Until recently, publications providing analytical solutions either neglected resistive components or assumed magnetic linearity (or both) in the problem formulation [5][6][7][8]. These unnecessary simplifications were overcome in [1] (and partly in [9][10][11]), where a unified theory for OFTC was proposed, offering analytical solutions for all aforementioned operation strategies while considering stator resistance and magnetic nonlinearity to minimize copper losses (only). The main idea was to reformulate the optimization problems implicitly using quadrics and finding the optimal solution by intersecting two respective quadrics.…”

mentioning

confidence: 99%

Generic loss minimization for nonlinear synchronous machines by analytical computation of optimal reference currents considering copper and iron losses

Hackl¹,

Kullick²,

Monzen³

2020

Preprint

Self Cite

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The unified theory (introduced in [1]), which allows to analytically solve the optimal feedforward torque control (OFTC) problem of anisotropic synchronous machines (SM), is extended by considering all relevant machine nonlinearities and copper and iron losses and, thus, minimizing the overall (steady-state) losses in the machine. Instead of the well known maximum torque per current (MTPC) operation strategy, maximum torque per losses (MTPL) is realized. The unified theory for the derivation of the analytical solution is briefly recapitulated. Moreover, current and speed dependent iron losses, as well as, magnetic saturation and cross-coupling effects are considered. The resulting nonlinear optimization problem is solved via online linearization of the relevant expressions. The linearization is exemplified for flux linkages and machine torque. The presented decision tree guarantees an optimal operation management and smooth transitions between all operation strategies such as MTPL, field weakening (FW), maximum current (MC) and maximum torque per voltage (MTPV). Finally, the extended unified theory is validated for a real, highly nonlinear SM.

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“…The current locus for the modes of operation can be seen on the circle diagram in Figure 1 for the case of an infinite IPM drive. Thorough studies on the behavior of PMSMs and SynRMs in the different modes of control operations can be found in [15][16][17]. …”

mentioning

confidence: 99%

Field Weakening Characteristics Computed with FEM-Coupled Algorithms for Brushless AC Motors

et al. 2018

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Finite Element Method (FEM) analysis tools are the most adopted in the design of brushless alternating current motors due to the advantage of considering multi-physics effects with dependencies of variables such as cross-coupling, saturation and others that are not possible to be modeled analytically with high precision. During the design process designers compute operation points such as maximum torque per ampere or flux weakening characteristics that cannot be targeted directly on the FEM tool. Therefore, designers make a sweep of simulations and post-processed the data in order to obtain the results, this is repetitive particularly in the conceptual phase of the design where features of the motor are still not defined. This paper presents nine algorithms as an alternative to compute with iterative methods operation points that cannot be targeted directly on a FEM tool. The algorithms must be coupled to the FEM tool and can compute complex points such as the characteristic current and modes of operations limits within acceptable range of error and times of execution for practical purposes. Validation of the algorithms using Jython is presented with results for the three types of brushless motors (non-salient, interior permanent magnet and reluctance motor).

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A unified theory for optimal feedforward torque control of anisotropic synchronous machines

Cited by 87 publications

References 43 publications

Experimental Identification of the Optimal Current Vectors for a Permanent-Magnet Synchronous Machine in Wave Energy Converters

Experimental Identification of the Optimal Current Vectors for a Permanent-Magnet Synchronous Machine in Wave Energy Converters

Generic loss minimization for nonlinear synchronous machines by analytical computation of optimal reference currents considering copper and iron losses

Field Weakening Characteristics Computed with FEM-Coupled Algorithms for Brushless AC Motors

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