A hybrid nine-level inverter for IM drive

This paper proposes a new hybrid nine-level inverter topology for IM drive. The nine-level structure is realized by using two three-phase two-level inverters fed by isolated DC voltage sources and six H-bridges fed by capacitors. The number of switches required in this topology is only 36 where as the conventional nine-level topologies require 48 switches. The voltages across the capacitors, feeding the H-bridges that operate at asymmetric voltages, are effectively balanced by making use of the switching state redundancies. In this topology, the requirement of DC link voltage is only half of the maximum magnitude of the voltage space vector. As the two-level inverters are powered by isolated voltage sources, the circulation of triplen harmonic current in the motor winding is prevented. The proposed drive system is capable of functioning in three-level mode in case of any switch failure in H-bridges. The performance of the proposed topology in the entire modulation range is verified by simulation study and experiment

The association of ideal cardiovascular health with incident type 2 diabetes mellitus: the Multi-Ethnic Study of Atherosclerosis

AIMS/HYPOTHESIS: Levels of ideal cardiovascular health (ICH) and incident type 2 diabetes mellitus have not been examined in a multiethnic population. We assessed the total and race/ethnicity-specific incidence of diabetes based on American Heart Association (AHA) ICH components. METHODS: Incident diabetes was assessed among 5,341 participants in the Multi-Ethnic Study of Atherosclerosis without prevalent diabetes between 2002 and 2012. ICH components (total cholesterol, BP, dietary intake, tobacco use, physical activity and BMI) were assessed at baseline and participants were categorised as having ideal, intermediate or poor cardiovascular health, as defined by the AHA 2020 impact goals. We developed a scoring system based on the number of ICH components (0–1 ‘poor’, 2–3 ‘intermediate’, and ≥4 ‘ideal’). HRs were calculated using Cox models. RESULTS: During a median follow-up of 11.1 years, we identified 587 cases of incident diabetes. After multivariable adjustment, participants with 2-3 and ≥4 ICH components vs 0-1 components had a 34% lower (HR 0.66; 95% CI 0.54, 0.80) and a 75% lower (HR 0.25; 95% CI 0.18, 0.35) diabetes incidence, respectively. There were significant differences by race/ethnicity: African-American and Hispanic-American participants with ≥4 ICH components had diabetes incidence rates per 1,000 person-years of 5.6 (95% CI 3.1, 10.1) and 10.5 (95% CI 6.7, 16.4), respectively, compared with 2.2 (95% CI 1.3, 3.7) among non-Hispanic white Americans. CONCLUSIONS/INTERPRETATION: Meeting an increasing number of AHA 2020 impact goals for dietary intake, physical activity, smoking, BP, cholesterol and BMI was associated with a dose-dependent lower risk of diabetes with significant variation by race/ethnicity