Direct Torque Control Schemes for Split-Phase Induction Machine

Abstract

In this paper, DTC (Direct Torque Control) algorithms for Split-phase Induction Machine (SPIM) are established. SPIM has two sets of three-phase stator windings, with a shift of thirty electrical degrees between them. The significant contributions of the present work are: a) Two new methods of DTC technique for SPIM are developed. They are called as Resultant Flux Control Method and Individual Flux Control Method. b) Advantages and disadvantages of both the methods are discussed. High torque ripple is a disadvantage for three-phase DTC. It is found that torque ripple in SPIM could be significantly reduced without increasing the switching frequency.

Comparison of Efficiency for Different Switching Tables in Six-Phase Induction Motor DTC Drive

“…To reduce these harmonics in the DTC of a six-phase induction machine, K. Hatua, et al [3] individual the flux control method. In this technique, two different two-level flux hysteresis controllers are used separately for two stator fluxes (Ψ s1 ,Ψ s2 ).…”

“…The other subspace is (z 1 − z 2 ), and the harmonics of the order 6k ±1, (k = 1, 3, ...) are mapped on it [5]. Because of the isolation of the neutrals of the two windings, the (o 1 − o 2 ) voltage vectors are all equal to zero [3], [8], [10].…”

“…Multi-phase machines with various structures are used in different applications. They are used in different applications including marine propulsion, railway traction, electric vehicles, and aerospace applications [1]- [3]. One of the major benefits of a six-phase induction machine is that it will continues working after cutting off one to three phases [1], [4].…”

“…Speed control of a six-phase induction machine can be accomplished by many approaches such as FOC [2], [6], [7] and DTC. Direct Torque Control of a six-phase induction machine has been reported in [3], [8]- [10]. Similar to a three-phase induction machine, there are two basic approaches for the DTC of a six-phase induction machine.…”

“…Accuracy in stator flux estimation is very important in the PWM-DTC of a six-phase induction motor. In [3] a split-phase induction machine is operated by two independent voltage source inverters. The proposed algorithms are complex and they are used in symmetrical sixphase induction machines.…”