Investigation and Experimental Validation of Sideband Harmonic Vibration of IPMSM with and without Skewed Slots for EVs

Due to their advantages of high power density and high efficiency, permanent magnet synchronous machines (PMSMs) are widely used in the field of electric vehicles (EVs). Vibration and noise are important indicators for evaluating the performance of PMSMs, and the skewed slot method is now widely used to mitigate the torque ripple and noise of motors. In the vector control strategy, the space vector pulse width modulation (SVPWM) method produces sideband voltage harmonics with a frequency near the switching frequency. These harmonics act on the magnetic field to generate an excitation force with a frequency near the switching frequency. This paper compares and analyzes the sideband harmonic current and the exciting force of a skewed slot motor and a straight slot motor during steady-state operation. The research results show that the skewed slot method can effectively mitigate the vibration and noise caused by sideband harmonics.

Vector control strategy of the five-phase VSI

The paper describes an example of the vector control strategy applied to five-phase two-level inverters. Two base methods are discussed. The first one is based on the standard space vector transformation, while the other uses state vectors which enable the definition of the basic physical quantities of the inverter. The proposed notation system offers an universal simplification of vector identification. It comprises a standardized proposal of notation and vector marking. This tool may be really useful for the description of inverter states and makes it possible to reach correlation between state and space vectors. All vectors are defined by use of the same digits. The proposed mathematical tool has been verified during simulation tests performed with the use of the PLECS program.

The Potential Container Habitats of Chikungunya Vector in Outbreak Area of Southern Thailand

ABSTRACT Chikungunya virus (CHIKV) is primarily transmitted by Aedes mosquitoes and is responsible for reemerging disease internationally. Container habitats of immature Aedes mosquitoes are often found around residential areas, thus water-holding container investigation is an important vector control strategy. This study aimed to survey mosquito species in container inhabiting stages and water-holding containers associated with the CHIKV outbreak in urban areas within the 4 villages of Hat Yai district in Songkhla province during 2019. The results indicated that of the 75 houses surveyed, 34 had water-holding containers; 78 out of 438 containers were positive for mosquitoes; and 34 were positive for mosquito stages. The house index (HI), Breteau index (BI), container index (CI), and pupal index (PI) were 46.87, 93.75, 14.92, and 271.88 for case houses, respectively. Specific container index (SCI) showed discarded containers such as bottles, cans, and tires. The findings suggest that Aedes aegypti was predominant in the surveyed urban area and might be the vector responsible for CHIKV transmission in Songkhla province.

Towards a Sustainable Vector-Control Strategy in the Post Kala-Azar Elimination Era

Visceral leishmaniasis (VL) is a potentially deadly parasitic disease. In the Indian sub-continent, VL is caused by Leishmania donovani and transmitted via the bite of an infected Phlebotomus argentipes female sand fly, the only competent vector species in the region. The highest disease burden is in the northern part of the Indian sub-continent, especially in the state of Bihar. India, Bangladesh, and Nepal embarked on an initiative, coordinated by World Health Organization, to eliminate VL as a public health problem by the year 2020. The main goal is to reduce VL incidence below one case per 10,000 people through early case-detection, prompt diagnosis and treatment, and reduction of transmission using vector control measures. Indoor residual spraying, a major pillar of the elimination program, is the only vector control strategy used by the government of India. Though India is close to its VL elimination target, important aspects of vector bionomics and sand fly transmission dynamics are yet to be determined. To achieve sustained elimination and to prevent a resurgence of VL, knowledge gaps in vector biology and behavior, and the constraints they may pose to current vector control methods, need to be addressed. Herein, we discuss the successes and failures of previous and current vector-control strategies implemented to combat kala-azar in Bihar, India, and identify gaps in our understanding of vector transmission towards development of innovative tools to ensure sustained vector control in the post-elimination period.