Eliminating the Third Harmonic Effect for Six Phase Permanent Magnet Synchronous Generators in One Phase Open Mode

Abstract

To insure stable operation and eliminate twice torque ripple, a topology for a six phase permanent magnet synchronous generator (SP-PMSG) with a neutral point connected together was analyzed in this paper. By adopting an extended transformation matrix, the mathematic model of the space vector control was established. The voltage and torque equations were deduced while considering the third harmonic flux and inductance. In addition, the suppression third harmonic method and the closed loop control strategy were proposed. A comparison analysis indicates that the cooper loss minimum method and the current magnitude minimum method can meet different application requirements. The voltage compensation amount for each of the methods was deduced which also takes into account the third harmonic effect. A simulation and experimental result comparison validates the consistency through theoretical derivation. It can be seen that all of the two control strategies can meet the requirements of post-fault.

Characteristics and Current Harmonic Control of N* Three-Phase PMSG for HVDC Transmission Based on MMC

“…Considering the analysis of the electromagnetic characteristics of the N* three-phase PMSG, it can be seen that the N* three-phase PMSG consists of n sets of three-phase PMSG units and the interaction between each unit is minimal, which could be neglected. According to reference [20], the mathematical model of the N*three-phase PMSG in the d-q coordinate system could be equivalent to that of a traditional three-phase PMSG. Thus, the d-q axes voltage transformation of one three-phase winding can be written as:…”

“…However, the multiple d-q approach leads to heavy cross-coupling between individual winding sets, which requires compensation in the control system [17][18][19]. The VSD modeling method of multiphase PMSG could avoid the problem of flux linkage coupling between multiple windings and dramatically reduces the difficulty of system control [20,21]. However, with the further increase of the number of phases (≥7), the multi-phase PMSG mathematical model obtained by VSD is very complex, which greatly increases the difficulty of analysis and the design of the controller.…”

Nonlinear Optimal Control for Six-Phase Induction Generator-Based Renewable Energy Systems

“…Besides, they exhibit fault tolerance and remain functional when one or more of their phases undergo a failure [10][11][12]. Models of six-phase induction generators combine the rotor's turn motion with the electrical dynamics of the stator's and rotor's phases [13][14][15][16][17]. To integrate 6phase dual star induction generators in the main electricity grid, two three-phase AC/DC converters can be used, each connected with one of the stator's three-phase windings [18][19][20].…”

Fast control of the six phase asymmetric generator with the 3rd harmonic current injection

“…5), on the injection coefficients k 13 , k 24 . These coefficients are calculated according to (4). The electromagnetic torque consists of three components resulting from the action of the basic harmonic, he action of the third harmonic and from the cooperation between these harmonics.…”

“…The generator under investigation is a low and variable speed machine with a large pole pair number. Such a machine has concentrated windings and therefore the third spatial harmonic component is not negligible [2][3][4]. This component is generated by the third harmonic of the windings specific electric loading.…”