An area-time efficient FPGA-implementation of online finite-set model based predictive controllers for flying capacitor inverters

Recently there has been an increase in the use of model-based predictive control (MBPC) for power-electronic converters. Especially for flying-capacitor multilevel converters (FCC) this offers an interesting possibility to simultaneously control output current and the capacitor voltages. The computational burden however is very high and often restrictive for a good implementation. In this paper a time and resource efficient design methodology is presented for the FPGA implementation of FCC MBPC. The control is fully implemented in programmable digital logic. Due to a parallel processing for the three converter phases and a fully pipelined calculation of the prediction stage an area-time efficient implementation is realized. Furthermore, this is achieved by using a high-level design tool. The implementation aspects for 3, 4 and 5-level FC inverters are discussed, with a focus on the 4-level case

On extended Kalman filters with augmented state vectors for the stator flux estimation in SPMSMs

The demand for highly dynamic electrical drives, characterized by high quality torque control, in a wide variety of applications has grown tremendously during the past decades. Direct torque control (DTC) for permanent magnet synchronous motors (PMSM) can provide this accurate and fast torque control. When applying DTC the change of the stator flux linkage vector is controlled, based on torque and flux errors. As such the estimation of the stator flux linkage is essential. In the literature several possible solutions for the estimation of the stator flux linkage are proposed. In order to overcome problems associated with the integration of the back-emf, the use of state observers has been advocated in the literature. Several types of state observers have been conceived and implemented for PMSMs, especially the Extended Kalman Filter (EKF) has received much attention. In most reported applications however the EKF is only used to estimate the speed and rotor position of the PMSM in order to realize field oriented current control in a rotor reference frame. Far fewer publications mention the use of an EKF to estimate the stator flux linkage vector in order to apply DTC. Still the performance of the EKF in the estimation of the stator flux linkage vector has not yet been thoroughly investigated. In this paper the performance of the EKF for stator flux linkage is studied and simulated. The possibilities to improve the estimation by augmenting the state vector and the consequences of these alterations are explored. Important practical aspects for FPGA implementation are discussed

On the calibration of the 3/2 model

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An accurate analytical approximation for the price of a European-style arithmetic Asian option.

For discrete arithmetic Asian options the payoff depends on the price average of the underlying asset. Due to the dependence structure between the prices of the underlying asset, no simple exact pricing formula exists, not even in a Black-Scholes setting. In the recent literature, several approximations and bounds for the price of this type of option are proposed. One of these approximations consists of replacing the distribution of the stochastic price average by an ad hoc distribution (e.g. Lognormal or Inverse Gaussian) with the same first and second moment. In this paper we use a different approach and combine a lower and upper bound into a new analytical approximation. This approximation can be calculated efficiently, turns out to be very accurate and moreover, it has the correct first and second moment. Since the approximation is analytical, we can also calculate the corresponding hedging Greeks and construct a replicating strategy.Options; Dependence; Structure; Prices; Hedging; Strategy;

Invloed van het strippen op de kwaliteit van de vis en mogelijkheden ervan aan boord van de vissersvaartuigen

The influence of gutting on the quality of fish is discussed. The conclusion of this study is that the usefulness of evisceration depends upon many factors: duration of the voyage, fish species, size and quality of the catch season (influence of temperature), etc.In most cases however, gutting is to be recommended. As it is a very laborious operation especially when important quantities of fish are caught and as it should be carried out carefully in order to keep the quality of the fish at a high level, gutting machines represent a real progress, allowing better working conditions. In recent years, several interesting machines were proposed abroad. A brief description of the most important types is given in this article

Influence of sodium tripolyphosphate and citric acid on the shelf life of thornback ray (<i>Raja clavata</i> L.)

Sodium tripolyphosphate dips (5 min in 12% solution) extended shelf life of thornback ray wings by about 2 days, improved the appearance and eliminated weight losses. With citric acid dips (5 min in 0.5% solution) a 3 day extension of storage life was obtained but the treatment had a slight bleaching effect and caused weight losses of about 5 %. Both compounds were effective in retarding the breakdown of urea with formation of ammonia in thornback ray