Optimum state voltage balancing method for stacked multicell converters

This paper presents a voltage balancing method for stacked multicell converters based on phase disposition pulse-width modulation. This method is based on minimizing a cost function to determine the optimum redundant state for capacitor voltage balance for each particular voltage level. The robustness of the proposed voltage balancing method is verified against static and dynamic unbalanced load conditions. Furthermore, a significant reduction in the switching frequencies of the power devices is achieved by using sawtooth carriers instead of standard triangular carriers without affecting the voltage balancing capability.Peer ReviewedPostprint (published version

Voltage balancing method for a seven-level stacked multicell converter using minimum-switching transitions

This paper presents a voltage balancing method for stacked multicell converters based on phase disposition pulse-width modulation. This method is based on minimizing a cost function to determine the optimum redundant state for capacitor voltage balance for each particular voltage level. The robustness of the proposed voltage balancing method is verified against static and dynamic unbalanced load conditions. Furthermore, a significant reduction in the switching frequencies of the power devices is achieved by using sawtooth carriers instead of standard triangular carriers without affecting the voltage balancing capability.Peer ReviewedPostprint (published version

The seven-level flying capacitor based ANPC converter for grid intergration of utility-scale PV systems

The installed capacity of grid connected PV plants has increased significantly over the past few years and is expected to continue its growth over the next decade due to the continuous demand for renewable energy and distributed generation systems. This paper presents a seven-level flying capacitor (FC) based active neutral point clamped (ANPC) converter for the connection of utility-scale PV system to the electricity grid. The multilevel voltage output of the topology provides high quality waveforms while maintaining the operational characteristics of NPC based converters for PV systems. The converter topology together with a method to regulate the FC voltages to their reference values and an optimal third harmonic injection for utilization of the DC-link voltage are presented. Simulation results for the operation of the grid connected converter under steady state and transient operation are provided in order to demonstrate the operation and performance of the topology in grid connected applications. © 2012 IEEE

The role of sensory evaluation in food quality control, food research and development: a case of cream cheese study

Sensory evaluation is a method of analysing, measuring and interpreting sensory perception responses to food, based on the five human senses, charac terised, in line with other scientific methods of measurement, by precision, accuracy and sensitivity. The material studied consisted of six varieties of cream cheese purchased on the commercial market and produced by a usual technological process. The sensory evaluation session involved assessment of colour, aroma, texture and taste by a group of 20 tasters over three series of tastings. From a ranking point of view, in descending order of the average scores obtained in the sensory evaluation of the characteristics of appearance, colour, texture, smell, taste and creaminess, the samples can be classified as follows: Philadelphia (S2), Hochland (S3), LaDorna (S1) Goldessa (S5), Delaco (S6) and KClassic (S4)