Sensitivity of a 5-phase Brushless DC machine to the 7th harmonic of the back-electromotive force

Eric Semail (1) , Xavier Kestelyn (1) , Alain Bouscayrol (1)

1 L2EP - Laboratoire d’Électrotechnique et d’Électronique de Puissance - ULR 2697

This paper presents a vector control of a 5-phase drive composed of a 5-leg Pulse Width Modulation (PWM) Voltage Source Inverter (VSI) supplying a permanent-magnet Brushless DC (BLDC) machine with trapezoidal waveform of the back-electromotive force (EMF). To achieve this control a Multi-machine Multi-converter model is used: the 5-phase machine is transformed into a set of two 2-phase fictitious machines which are each one controlled in a (d,q) frame as 3-phase machines with sine waveform back-EMF. In comparison with the 3-phase BLDC drives, the 5-phase ones present one particularity: a high sensitivity to the 7th harmonic of back-EMF. Experimental results show that the 7th harmonic of back-EMF, which represents only 5% of RMS back-EMF, induces high amplitude parasitic currents (29 % percent of RMS current). The model allows to explain the origin of this sensitivity and how to modify simply the control algorithm. Experimental improvements of the drive are presented.

Mots clés: multiphase; brushless machine; five-phase; 5-phase; multiphase drive

Domaines: Energie électrique

Eric Semail, Xavier Kestelyn, Alain Bouscayrol. Sensitivity of a 5-phase Brushless DC machine to the 7th harmonic of the back-electromotive force. Power Electronics Specialists Conference, 2004. PESC 04. 2004 IEEE 35th Annual, Jun 2004, AACHEN, Germany. pp.4564 - 4570, ⟨10.1109/PESC.2004.1354807⟩. ⟨hal-01314306⟩