Cascaded multilevel inverter for hybrid electric vehicles

Hybrid Electric Vehicle (HEV) is an emerging technology in the modern world because of the fact that it mitigates environmental pollutions and at the same time increases fuel efficiency of the vehicles. Multilevel inverter controls electric drive of HEV of high power and enhances its performance which is the reflection of the fact that it can generate sinusoidal voltages with only fundamental switching frequency and have almost no electromagnetic interference. This paper describes precisely various topology of HEVs and presents transformer less multilevel converter for high voltage and high current HEV. The cascaded inverter is IGBT based and it is fired in a sequence. It is natural fit for HEV as it uses separate level of dc sources which are in form of batteries or fuel cells. Simulation has been done in PSEVI as well as MATLAB and its responses match the theoretical concept of multilevel inverter

Generation of possible switching patterns for VSI using microcontroller for the control of PM BLDC motor

It has been observed that adoption of different possible switching patterns/schemes affects the transient behaviours such as phase current and torque of a PMBLDC motor. Four possible switching patterns are achieved by modulating only upper/lower switches and incoming/outgoing phase switches. For the purpose of control of PMBLDC motor low cost ATMEGA 32 micro-controller is used to generate all the four possible switching schemes. Use of dummy hall sensor is a near ideal and cheaper approach to prepare micro-controller for the control of PMBLDC motor. Dummy Hall sensor signals where generated for variable speed reference with the help of micro-controller to analyse inverter voltages. Provision is made to bypass the generated dummy hall sensor signal with actual hall sensor signal from the motor for the control purposes

Not Available

Not AvailableConservation agriculture (CA) including reduced or no-tillage and crop residue retention, is known to be a self–sustainable system as well as an alternative to residue burning. The present study evaluated the effect of reduced tillage coupled with residue retention under different cropping systems on soil properties and crop yields in a Vertisol of a semiarid region of central India. Two tillage systems – conventional tillage (CT) with residue removed, and reduced tillage (RT) with residue retained – and six major cropping systems of this region were examined after 3 years of experimentation. Results demonstrated that soil moisture content, mean weight diameter, percent water stable aggregates (>0.25 mm) for the 0–15 cm soil layer were significantly (P < 0.05) affected by tillage practices. Soil penetration resistance was significantly higher for RT than CT. Irrespective of soil depth, there was higher soil organic carbon (SOC) for RT than CT. The SOC fractions followed in the order: non-labile > moderately labile > less labile. At the 0–15 cm depth, the contributions of moderately labile, less labile and non-labile C fractions to total organic C were 39.3%, 10.3% and 50.4% respectively in RT and corresponding values for CT were 38.9%, 11.7% and 49.4%. Significant differences in different C fractions were observed between RT and CT. Soil microbial biomass C concentration was significantly higher in RT than CT at 0–15 cm depth. The maize–chickpea cropping system had significantly (P < 0.05) higher soybean grain equivalent yield of 4.65 t ha–1 followed by soybean + pigeon pea (2 : 1) intercropping (3.50 t ha–1) and soybean–wheat cropping systems (2.97 t ha–1). Thus, CA practices could be sustainable management practices for improving soil health and crop yields of rainfed Vertisols in these semiarid regions.Not Availabl