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In this paper, an overmodulation (OVM) technique is proposed based on Fourier analysis. The OVM trajectory is a mixture of six arc segments of the inscribed circle and six vertices of the voltage hexagon. By adjusting the holding angle at each vertex, the modulation index is determined. The fundamental component is expressed as a function of the holding angle, and the linearity with the modulation index is obtained by the inverse relation. This algorithm guarantees seamless transitions from the space vector pulsewidth modulation to OVM and finally to the six-step. Apart from the variable voltage variable frequency control, the proposed algorithm works well with the interior permanent magnet synchronous motor current controller. By computer simulation and experimental evidence, the effectiveness is demonstrated.

Sjögren’s syndrome (SS) is a chronic and systemic autoimmune disease characterized by lymphocytic infiltration in the exocrine glands. Although an association between inflammasome activation in peripheral blood cells and disease activity of SS has been reported, little is known about inflammasome activation in exocrine glands and its underlying mechanisms. We investigated the levels of AIM2, ASC, caspase-1, IL-1β, and IL-18 in salivary gland tissues and saliva from SS patients. We found that AIM2, ASC, Caspase-1, and IL-18 were increased in the saliva from primary SS patients compared with healthy and sicca controls. Numbers of AIM2-ASC speck also were elevated in the salivary gland epithelial cells of SS patients. The expression of caspase-1 correlated with type I interferon (IFN) signature gene expressions in the minor salivary glands (MSG) of SS patients, and was increased by type I IFN stimulation in salivary gland epithelial cells (SGECs). The AIM2 inflammasome was activated in SGECs after stimulation by the AIM2 ligand, poly(dA:dT). In addition, type I IFN accelerated AIM2 inflammasome activation as determined by the increased expression of caspase-1 in SGECs. In conclusion, the AIM2 inflammasome activation is increased in the SGECs of SS patients, and therefore should be considered an important pathogenic mediator of SS disease.

An overmodulation (OVM) technique is proposed based on Fourier analysis. The OVM trajectory is a mixture of 6 arc segments of the inscribed circle and 6 vertices of the voltage hexagon. By adjusting the dwell time at each vertex, the modulation index is determined. The fundamental component is expressed as a function of the dwell time, and the linearity with the modulation index is obtained by the inverse relation. This algorithm guarantees seamless transitions from the space vector PWM (SVPWM) to OVM and finally to the six-step. Apart from the VVVF control, the proposed algorithm works well with the interior permanent magnet synchronous motor (IPMSM) current controller. By computer simulation and experimental evidences, the effectiveness is demonstrated.