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Three-level converters are widely utilized by industries thanks to the advantages of less dv/dt and less frequency common mode voltage in comparison to conventional two-level PWM inverters. Since these converters utilize switches as fully on or fully off elements and they feed a floating output system, common mode voltage will be unavoidable. This paper presents a comprehensive analysis of common...
This paper presents an adaptive PWM control scheme of four-cell interleaved boost-type switching-mode rectifier, used as an input stage of auxiliary power supply of electrical vehicles, and its operation under regular, as well as under specific operating conditions - failure of one or more IGBTs.
With high input voltage or light load, the peak of AC line current for critical conduction mode (CRM) flyback power factor Correctors (PFCs) appears notably distorted. In this paper, the reasons of line current distortion are investigated. Moreover, the relationship between line current peak distortion and high input voltage or light load is presented. Based on theoretical analysis, a simple improved...
This paper shows measurements of the emission of harmonics by a small windpark. The spectrum consists of the characteristic harmonics associated with six-pulse converters and a broadband spectrum covering frequencies at which emission normally is not present. These frequencies are caused by the switching pattern of the power-electronics converters. Similar spectra have been reported by other authors...
Voltage Source Converter (VSC) technology is very common in high-voltage direct current (HVDC) transmission systems. Compared to conventional VSC technology Modular Multilevel Converters (MMCs) offer advantages such as higher voltage levels, modular construction, longer maintenance intervals and improved reliability. For power transmission, stability, robustness of the control and especially the behavior...
Phase locked loop (PLL) is an important part of the current-controlled grid-connected converter. Its job is to estimate the phase angle of the grid voltage. If the PLL is not robust, the grid-voltage distortion will lead to an error in the estimated phase leading to a degradable performance of the converter. In this paper, the effect of the PLL on the operation of a current-controlled voltage-source...
This paper proposes new control strategy for grid connected three-phase Voltage Source Converter (VSC). The strategy is designed to overcome problems of conventional voltage oriented VSC control operating under distorted grid voltage. Proposed control strategy cancels the influence of characteristic distribution grid voltage harmonics, and injects close to sinusoidal current to the grid, with permitted...
This paper presents how through a suitable DC link regulation strategy, the asymmetric cascade H-bridge converter can perform STATCOM and active filter functions simultaneously. Initially DC link regulation strategy for a STATCOM function is developed, and then an adaptation of the strategy is presented in order to show the device works as an active filter. A two cells binary prototype is used to...
The combination of extensive cable networks and wind turbine converters has been identified as a potential cause of resonances. A modelling approach for a doubly fed induction generator and a full power converter fed generator for harmonic penetration studies is developed and discussed. An example offshore wind farm is then studied in the simulation package IPSA using the detailed wind turbine generator...
The Distributed Power Flow Controller (DPFC) is a new device within the FACTS family. It is emerged from the UPFC and has relatively low cost and a high reliability. The DPFC consists of two types of converters that are in shunt and series connected to grids. The common dc link between the shunt and the series converters is eliminated. The active power exchange between the shunt and series converters...
Field experiences have shown that transmission systems using voltage sourced converters can produce high frequency harmonic resonances in the VSC station environment. Modern XLPE cable terminations using non-geometric stress grading can be susceptible to degradation under these harmonics. The paper presents the high frequency voltage effects in XLPE cable terminations, under conditions that are representative...
The industrial electronics market is continuously changing following the users demand. This paper introduces the current industrial electronics applications and is focused in the medium-voltage high-power ones. The multilevel approach is the most attractive solution to achieve the challenges that medium voltage-high power applications arise. Several commercial examples are introduced and some of the...
This paper presents a detailed analysis of a Single-Stage Single-Switch Power Factor Corrector, S4PFC, with Integrated Magnetic, IM. The chosen topology for study for implementing S4PFC is based upon a Boost Converter operating in Discontinuous-Mode for Input Current Shaping, and a Forward Converter for output voltage regulation. Detailed are the modes of converter operation, as well as essential...
The shunt active filters are based on power converters driven to generate a current waveform injected in parallel to the system in order to compensate harmonics or to supply reactive power. Several topologies have been studied based either on voltage-source converters (VSC) or current-source converters (CSC), from the standpoint of power topologies and from the point of view of control strategies...
The paper makes an in-depth analysis on conventional bridge rectifier, the working process of boost chopper, control method, input changes in current law and etc. Based on it and according to the principle of energy equivalent, the relationship between chopper conduction ratio and step-up ratio is given, and makes explanation of boost range. By grafting circuit connection and introducing non-linear...
In this work we present an Asymmetric Multicell Converter fed by a single DC source per phase. The proposed control method is divided in two parts. Firstly, the main cells are handled by using a fundamental frequency switching pattern. In parallel, a Model Predictive strategy is used to control the remaining cells which use floating capacitor instead of a DC source. The target of this controller is...
The characteristics of high-frequency and high-speed for high-speed permanent magnet synchronous motor have led to great difficulties for control. The starting and setting is complicated and losing synchronous easily. The current harmonics for the high-speed motor power supply is larger. The high-speed permanent magnet synchronous motor (PMSM) fuzzy-PID controller is proposed in this paper combined...
This paper presents modeling of line-frequency converters with and without phase control. The operation of the converters can be described by two algebraic equations based on defined mapping functions. Unlike previous work that develops the mapping functions using direct Fourier expansion, double-Fourier series method is applied to avoid the assumption on the perturbation frequency. The resulting...
This paper presents an approach to generate three-phase multi-level AC voltage output using a switching matrix device and photovoltaic (PV) panels. The approach is based on the dynamic reconfiguration of PV panels distributed in a matrix. The principle is similar to methods used in multi-level inverters related to the technique of matrix reconfiguration. The concept is to switch in and out solar panels...
In view of the drawback of traditional bridge 4-quadrant converters which need higher dc-side operating voltage, a new type quasi-buck topology of converters is proposed whose dc-side voltage is reduced by approaching 50%, thus appropriate for lower voltage applications. This paper presents the modeling with the state space averaging method, and steady state theoretical analyses of the converter....
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