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This paper proposes a digital online efficiency optimization technique for DC/DC Dual Half-Bridge Series Resonant Converters. The proposed technique implements an advanced modulation scheme which exploits the degrees of freedom inherently available in the converter modulation space in order to simultaneously regulate the output voltage and maintain the system in its maximum efficiency point. Furthermore,...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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 an Indirect Matrix Converter (IMC) with two output stages feeding an open-end winding induction machine is presented. The IMC has the advantage of having nobulky energy storage elements and with the two output stages up to 1.5 times the input phase voltage can be obtained across the windings of the machine, without overmodulation. A vector control scheme for the machine currents is used...
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...
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...
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...
In this paper, we discuss the principles of operating the electric spring (ES) as a reactive power compensator and as a power factor corrector. The theory on electric springs with capacitors for voltage stabilization is reviewed to present a general idea on the behavior of ES. Further discussion focuses on the principle of ES with batteries to cover its eight possible operating modes and their usefulness...
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, motor drive system fed by single phase diode rectifier without Power Factor Correction (PFC) circuit is proposed. The motor drive considered in this paper consists of single phase diode rectifier, three-phase inverter, and small DC-link capacitor. Since DC-link capacitor is small, grid input current of the diode rectifier can be directly affected by electrical output power of the inverter...
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