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In this paper, a 600 KW electrical balance of plant (EBOP) for a molten carbonate fuel cell (MCFC) power plant is introduced. The requirements for EBOP are categorized into as follows : demands on grid interconnection and operational interface with a fuel cell. EBOP has three modes of operation, i.e. grid-connected (GC) mode, grid-independent (GI) mode, and grid-synchronization (GS) mode, to control...
With its new SineFormertrade EPCOS is introducing a fully new output filter technology for frequency converters. In contrast to conventional filter topologies the new SineFormertrade simultaneously converts the phase-to-phase voltage into a sinusoidal signal, damps the common mode currents and also forms the conductor-to-ground voltage to sine shaped voltage. This offers users a number of key benefits...
In this paper, a direct control of a flying capacitor inverter is proposed. This control allows to limit the number of commutations in a switching period with the use of a pre-calculated output voltage profile. A predictive control is made for the 3 phases 4 levels inverter in a active filtering operation. The advantages of this direct control is to reduce the switching frequency of the IGBTs, to...
A control algorithm is proposed for a three-phase hybrid power filter constituted by a series active filter and a shunt passive filter. The control strategy is based on the dual formulation of the vectorial theory of electrical power, so that the voltage waveform injected by the active filter is able to compensate the reactive power, to eliminate harmonics of the load current and to balance asymmetrical...
This work investigates the influence of the choice of the operation point (Deltai @ fs) under the final volume of PFC boost converter. Boost inductor, EMI filter and thermal heatsink are the elements which main influences in the converter volume. These elements are strongly influenced by the chosen operation point, showing a direct relationship among them. With the increase of switch frequency and...
This document describes the implementation of the model predictive direct torque control (MPDTC) algorithm for the control of three-phase induction motor drives comprising a three-level dc-link inverter with an output LC filter. As the filter introduces delays in the system, the motor torque and flux are no longer directly controllable. Therefore the inverter torque and flux are introduced and the...
The aim of this paper is to propose an over current limitation and voltage control strategy for a grid connected inverter with a LC output filter used in distributed generation and in case of voltage sag. This strategy relies on the control of LC output filter voltage with a resonant controller. This controller has to control current and load voltage throughout voltage sag. Generally, resonant controller...
Incipient fault detection and isolation (FDI) in the current sensors of a controlled induction motor is addressed by an original diagnosis system based exclusively on the three-phase signals model. In this way we avoid a reduction in the performance of the FDI system due to the uncertainty in the machine model. Assuming that the three current signals are measured, the proposed FDI system is made of...
In this paper an algorithm for optimal design of active power filters using Strength Pareto multi-objective optimization approach is proposed. Some parameters of the repetitive current controller together with the inverter's DC bus voltage have been considered as design variables. Different optimizing pairs of objective functions including THD of the line currents and the transient response of the...
This paper presents several shaft voltage reduction techniques for doubly-fed induction generators in wind turbine applications. These techniques includes: pulse width modulated voltage without zero vectors, multi-level inverters with proper PWM strategy, better generator design to minimize effective capacitive couplings in shaft voltage, active common-mode filter, reducing DC-link voltage and increasing...
A deeper design approach for three-phase electrical filters to reduce CM and DM emissions is presented. Equations to consider mutual impact of common mode (CM) and differential mode (DM) filter design are developed. After introducing a typical drive system and today's filter design, the new approach is proposed and proven by experimental results.
This work presents a Neural Networks based intelligent Active Power Filter control unit for harmonics current elimination. The paper is centered on an Improved Three-Monophase (ITM) method and a novel one called Two-Phase Flow (TPF) method for detecting harmonics from disturbed currents due to non linear loads in electric power systems. The TPF method introduces new currents decomposition in the DQ-space...
The systematic use of Active Power Filters, APFs, to compensate nonlinear loads, has extended the use of the instantaneous reactive power theory. Originally, the p-q theory appeared; it obtained constant instantaneous power in the source side after compensation. Later, other formulations have been developed. They have allowed different compensation objectives to be obtained. Nevertheless, all of them...
This contribution deals with a shunt-type active power filter designed mainly for railway applications (50-Hz and 16.7-Hz electrification systems) which is able to compensate undesired harmonic currents as well as reactive power. Its control algorithm employs an optimized DFT-based fundamental current and voltage estimator generating an accurate control reference signal. The APF configuration, the...
Parallel converter architecture using intercell transformers is one of the most adapted architecture for low-voltage, high-current and fast transient power conversion applications. Interleaved buck converter with intercell transformers main interest is the current ripple reduction in each converter arms which is not the case with non-coupled inductor architectures. As a consequence, current constraints...
A novel MPPT algorithm for three-phase grid-connected photovoltaic generation systems is presented in this paper. Reference is made to a conversion scheme consisting in two balanced arrays of PV modules, each one feeding a standard 2-level three-phase voltage source inverter (VSI). The dc-link voltages of each VSI are regulated according with the requirement of the proposed MPPT algorithm, based on...
A delta-sigma modulator converts an analog input signal into a high-frequency stream of single bits with out-off band noise. A high-resolution signal is extracted from the bit-stream with an appropriate low pass filter. The paper emphasizes on the utilization of SincK-filters as low pass filter and proposes a sampling method that is synchronized with the controller to incorporate a regular sampling...
This paper proposes a new three-phase positive sequence detector. The scheme is based on a stationary reference frame and a Moving Average Filter (MAF) that guarantees the complete cancellation of harmonics and grid imbalances. The performance of the MAF is mathematically analyzed and a proper selection of the optimal filter's window width is realized. The proposed detector operates in open loop and...
The paper presents the speed sensorless control of the induction motor in the system with the voltage inverter and LC filter. The LC filter is used to smooth the motor currents and voltages. In the control system the non-linear control method is used. For the state variables estimation the disturbance observer is implemented. Because of the voltage drop and phase shift caused by the LC filter the...
This article presents an automated method for the sizing of filter parameters taking into account stability and quality criteria. The analytical linearized model of the system is automatically built from a circuit description. System stability conditions are firstly assessed on this model with the Routh-Hurwitz criterion. Then, filtering and damping conditions are introduced. To complete the sizing,...
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