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The paper proposes a computationally efficient finite state model based current control of a three-level neutral point clamped (NPC) five-phase voltage source inverter. The space vector model of a five-phase voltage source inverter (VSI) yields 243 space vectors, with 240 active and three zero vectors. The presented technique utilizes a modified switching algorithm to reduce the computation time while...
The internal nodes of switched capacitor converters can be used to provide multiple pulsed width modulated voltages that, in combination with filter inductors, can extend the available dc outputs. Such converter architecture requires models that accurately predict the behaviour of switched capacitor converters operated in current output mode. Based on the well-known output impedance model, a new circuit...
LCL filter is becoming an attractive choice over conventional L filters for grid-connected voltage source inverters (VSI) due to smaller inductor size and better attenuation of the ripple components in the grid current. The modulation of the VSI generates switched voltages which results in distorted currents. In this paper, a simple closed form analytical expression is derived for the higher order...
Multi-level rectifier topologies are widely used in applications of the wide-power range. T-type topology, which is one of many three-level topologies, has an advantage in terms of an efficiency compared to a neutral-point clamped (NPC)-type. In applications using T-type rectifier topology, the interest in reliability has been increased recently. Therefore, a tolerance control for T-type rectifiers...
This paper proposes a novel implementation of an FPGA-Based Model Predictive Control (MPC) for a SiC Quasi-Z-Source inverter. To speed-up computations, to satisfy the control requirements and to increase the switching frequency, an MPC algorithm is designed for parallel processing and is implemented on an FPGA. This is suitable for high-sampling/switching frequency operation that enables the use of...
Special switching sequences involving division of active state time are used in space-vector-based generation of pulse width modulation (PWM) waveforms. This paper proposes a hybrid PWM technique which is a combination of the conventional and special switching sequences. The proposed hybrid PWM technique reduces the peak-to-peak torque ripple at high speeds of an induction motor drive. Supporting...
This paper proposes a novel direct torque control (DTC) scheme to reduce the torque and stator flux ripples for permanent-magnet synchronous motor (PMSM) drives using a relatively low sampling frequency. Unlike the conventional DTC in which the voltage vectors are determined by hysteresis controllers, the proposed DTC uses nonlinear saturation comparators and a duty ratio modulation scheme for switch...
This paper presents a novel loss balancing modulation method for more evenly distributing semiconductor losses in multilevel active neutral-point-clamped (ANPC) converters. The presented method is achieved by optimally utilizing the redundant switching states of space vector pulse width modulation (SVPWM) in ANPC converters. A comparison of the effect of losses distribution between the proposed loss...
DC capacitor voltage imbalance is an inevitable technical concern for the multilevel diode-clamped converters with number of levels higher than two. This paper addresses the balancing of the capacitor voltages based on the capacitor current equalization considering a minimum loss space vector pulse width modulation (MLSVPWM) algorithm for five-level diode-clamped converters. In diode-clamped converter...
In this paper comprehensive space vector model of a thirteen-phase voltage source inverter (VSI) is reported. The paper also discusses the space vector Pulse Width Modulation (SVPWM) of a thirteen-phase voltage source inverter (VSI) with the aim of producing sinusoidal output waveform. Generalized space vector theory is used to achieve the SVPWM. As per the general inverter switching theory there...
The inverter often connects to load or grid through inductor-capacitor (LC) filter for feeding the filtered voltage and current. The carrier based modulation techniques, such as sinusoidal pulse width modulation (SPWM) and space vector modulation (SVM), require some kind of current control in LC filter connected inverter to damp out the LC resonance. The major advantage of flux vector modulation for...
In this paper, a new post-fault modulation strategy is proposed to operate the direct matrix converter (MC) as close as possible to its desired normal operating under an open-switch fault condition. The proposed strategy determines the switching states of the eight, out of the nine, remaining healthy switches of the converter, to generate the reference voltage. The corresponding duty cycles of the...
To improve the efficiency of the photovoltaic (PV) system, the centralized topology using three-level inverters are widely used. In this system, PV modules are separately connected to the split DC-links. This causes a decrease of maximum power point tracking (MPPT) efficiency under the partial shading condition. This paper proposes an independent control of two DC-link voltages for separate MPPT of...
DC capacitor voltage balance is one of the key issues in the control of five-level NPC (neutral point clamped) converter. In this paper, it analyses the influence of space vectors to the DC voltage balance in five-level NPC converter SVM (space vector modulation) strategy and present a novel DC capacitor voltage self-balancing SVM strategy. The novel strategy divides the whole five-level space vector...
This paper proposes an improved space vector modulation (SVM) method for the 3-level neutral point clamped (NPC) inverter that serves as a bidirectional power conversion system for renewable energy micro-grid. Conventional SVM for the NPC converter majorly deals with neutral point (NP) balance issue without considering switching loss. The proposed SVM method balances the NP voltage and minimize the...
In this work it is presented a Current Source Converter (CSC) topology that helps to mitigate double line frequency power ripple (low frequency) effect. Low frequency power ripple presented in single-phase systems propagates through DC-bus converter. This low frequency ripple reduction allows to increase the power converter density by reducing the volume of the DC inductor, without lack of stiffness...
In this paper a generalized multi-phase space vector theory is considered for developing the space vector modulation of a three-phase to seven-phase direct matrix converter (DMC). The modulation is based on the control of the voltage vectors in the first d-q plane, while imposing the remaining voltage vectors in the second and the third planes (x1–y1, x2–y2) zero. The duty cycles of the bidirectional...
Space Vector Modulation (SVM) is a powerful method which enables some freedom to generate the modulation sequences and modify the performances of converter. However, in the multi-level converter structures, the number of switching state redundancies significantly increases, and the determination of modulation sequences becomes ambiguous because there are too many possible combinations and arrangements...
Variable speed drives (VSD) constructed with doubly-fed machines (DFM) offer interesting flexibility for power electronic drive design. They also offer opportunities for controlling interactions with an ac grid. Design options are most flexible for the VSD DFM when the machine stator can be operated from an ac or dc source, selected “on-the-fly” as appropriate. This paper presents a SCR-based transfer...
In order to overcome the excitation problem of three-stage synchronous machine(TSM) used as starter for the engine cranking, this paper presented a novel three-phase open-winding structure of the exciter for the proposed machine with the dual-inverter for supplying the integrated AC and DC excitation power. The operation principle of the dual-inverter and the control method of the three-phase AC excitation...
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