Novel Measurement Disturbance Rejection Current Control for Linear Switched Reluctance Motor Drives

Phase currents corrupted by measurement disturbances mainly arising from sensor noise, PWM switching noise, DC-link ripple, and measurement offset, increase torque or force ripple, acoustic noise and EMI. This paper presents a novel current controller for a linear switched reluctance motor (Lobo et al., 2006) to suppress measurement disturbances without extra hardware. The controller is based on an extended state observer (ESO) and a nonlinear proportional controller (NLP). The proposed method does not require an accurate mathematical model of the system and lends itself for implementation with a low-cost DSP controller. The proposed ESO is exploited to estimate measurement disturbances on measured phase currents and the proposed NLP compensates for measurement disturbances estimated by the ESO. The performance of the proposed current control is validated through dynamic simulations and experiments on linear switched reluctance motor drive. Analytical and experimental results prove that measurement disturbances contained in phase currents are mitigated by the proposed control method. Moreover, the rejection of measurement disturbances results in a reduction of force ripple and acoustic noise. From this study, it is inferred that the proposed current control technique is a strong candidate to suppress measurement disturbances with the same promising results without extra hardware in other motor drives as well.