Power-HIL Application Analysis of a 3-level Inverter for PMSM Machine

Power-HIL simulation is one of the emerging areas in power electronics development nowadays. It offers a convenient test environment for the whole power electronics hardware but eliminates the necessity of motor test benches and rotating machines. Selecting a suitable power amplifier for the simulator is however a challenging task. Switching power supplies can be an interesting option as Power Amplifier, but they have to offer superior power capability and dynamic performance over the DUT (Device Under Test), while maintaining high enough switching frequency to meet the dynamic requirements as well. Using commercially available inverters as Power Amplifiers would be an attractive option, if they can achieve the desired emulation accuracy. This paper investigates the possibility of using a common 3-level inverter with an L-C-L coupling network as a Power Amplifier for a P-HIL simulator, to emulate a PMSM (Permanent Magnet Synchronous Machine) machine

Optimal payments to connected depositors in turbulent times - a Markov chain approach

We propose a discrete time probabilistic model of depositor behavior which takes into account the information flow among depositors. In each time period each depositors' current state is determined in a stochastic way, based on its previous state, the state of other connected depositors and the strategy of the bank. The bank offers payment to impatient depositors who accept or decline them with certain probability, depending on the offered amount. The connections between depositors affect the evolution of the state trajectory as well: the more other connected depositors demand money from the bank, the larger is the probability that the depositor turns also impatient. Our principal aim is to see how are the optimal offers of the bank if it wants to keep the expected chance of a bank run under a certain level and minimize its expected payments, while taking into account the connection structure of the depositors. We show that in the case of the proposed model this question results in a nonlinear optimization problem with nonlinear constraints, and that the method is capable of accounting for time-varying resource limits of the bank. Optimal offers increase a) in the degree of the depositor; b) in the probability of being hit by a liquidity shock, and c) the effect of a neighboring impatient depositor

The Euro Crisis and Contagion among Central and Eastern European Currencies

This study analyses the Czech, Hungarian, and Polish currencies by examining the statistical characteristics of the Swiss franc as well as the ECB monetary policy in order to indicate shocks in these markets between 2002 and 2013. The abundance of monetary easing decisions can be used as a viable sign of market misbehaviour in addition to the low probability of extreme exchange rate fluctuations. Indeed, the temporal distribution of extreme currency fluctuations provides vital information about the nature of the recent crisis. Contagions can be defined as increased correlations during periods of crisis, while divergence means a significant decrease in this regard. Methodologically, common movements in this study were calculated by using DCC-GARCH modelling. The findings of this study underline the special features of the Swiss franc exchange rate, notably that its extreme fluctuations can be managed by using swap agreements and that it tended towards divergences during the crisis era. These results support the idea of avoiding lending in reserve currencies