On the Modeling of Commutation Transients in Split-Phase Synchronous Motors Supplied by Multiple Load-Commutated Inverters

Split-phase synchronous motors equipped with multiple-stator three-phase windings, each supplied by a load-commutated inverter, play an important role in today's very high power electrical-drive applications. A criticality of these systems is the possibility that commutations occur in different motor windings simultaneously. The resulting electromagnetic transient depends on the magnetic coupling of motor phases among them and with rotor circuits. In this paper, a model to describe this phenomenon is presented along with some dedicated tests, conducted on various split-phase configurations, to assess the model validity.

Nomenclature

Number of stator windings of the split-phase machine.

Displacement angle between stator windings.

Commutation angle.

,

Firing angles of the load-commutated inverters (LCIs) that supply windings 1 and 2.

,

Line-to-line voltages of stator windings 1 and 2.

,

Motor electromotive forces (EMFs) between phases and in windings 1 and 2.

,

Currents in phases and of stator winding 1.

,

Currents in phases and of stator winding 2.

DC-link current (average value).

Commutation inductance of a three-phase machine.

,

Commutation circulating current in windings 1 and 2.

,

Subtransient inductances of an individual winding.

Rotor position in electrical radians.

Supply electrical pulsation.

Line-to-line voltage fundamental (peak value).

,

Self-inductances of the proposed split-phase machine model.

Mutual inductance of the proposed split-phase machine model.

Leakage-inductance term in the expression of .

Self-leakage inductance of phase in winding 1.

Mutual leakage inductance between phases and .

, ,

Fundamental of the measured supply voltage , EMF , and current .

Phase shift between and .

Phase shift between and .