Аннотация:
This paper presents a nonlinear optimal direct
torque control (DTC) scheme of interior permanent magnet
synchronous motors (IPMSMs) based on an offline
approximation approach for electric vehicle (EV) applications.
First, the DTC problem is reformulated in the stationary
reference frame in order to avoid estimating the stator flux
angle, which the previous DTC schemes in the rotating stator
reference frame require. Thus, the proposed DTC method
eliminates the Park’s transformation and consequently it
reduces the computational efforts. Particularly, since the
estimated stator flux angle is not accurate in low speed range,
the proposed method that does not need this information can
significantly improve the control performance. Moreover, a
nonlinear optimal DTC algorithm is proposed to deal with the
nonlinearity of the IPMSM drive system. In this paper, a simple
offline θ-D approximation technique is utilized to appropriately
determine the controller gains. Via an IPMSM test-bed with a
TI TMS320F28335 DSP, the experimental results demonstrate
the feasibility of the proposed DTC method by accomplishing
better control performances (e.g., more stable in low speed
region, much smaller speed and torque ripples, and faster
dynamic responses) compared to the conventional proportionalintegral
(PI) DTC scheme under various scenarios with the
existence of parameter uncertainties