• Proceedings of the KIPE Conference
• /
• 2018.07a
• /
• pp.114-116
• /
• 2018

This paper presents a control strategy to achieve the balanced sinusoidal output currents, as well as sinusoidal input currents for the matrix converter (MC) under unbalanced input voltages. By regulating the modulation index of the converter according to the instantaneous input voltages, the output currents are kept balanced and sinusoidal. In order to obtain sinusoidal input currents, the input power factor angle should be dynamically calculated based on the positive and negative sequence components of the input voltages. This paper proposes a simple method to construct the expected input power factor angle without the complicated sequence component extraction of input voltages. Simulation results are given to validate the effectiveness of the proposed control strategy.

• 전기의세계
• /
• v.22 no.4
• /
• pp.25-29
• /
• 1973

The computation of transmittances between arbitrary input and output nodes is of particular interest in the signal flow graph theory imput. The signal flow matrix [T] can be defined by [X]=-[T][X] where [X] and [Y] are input nose and output node matrices, respectively. In this paper, the followings are discussed; 1) Reduction of nodes by reforming the signal flow matrix., 2) Solution of input-output relationships by means of Gauss-Jordan reduction method, 3) Extension of the above method to the matrix signal flow graph.

• International Journal of Control, Automation, and Systems
• /
• v.6 no.5
• /
• pp.670-676
• /
• 2008

While the matrix converter has many advantages that include bi-directional power flow, a size reduction, a long lifetime, and sinusoidal input currents, it is vulnerable to the input voltage disturbances, because it directly exchanges the input voltage to the output voltage. So, in this paper, a critical evaluation of the effect of various abnormal voltage conditions like unbalanced power supply, balanced non-sinusoidal power supply, input voltage sags and short time blackout of power supply on matrix converter fed induction motor drives is presented. The operation under various abnormal conditions has been analyzed. For this, a 230V, 250VA three phase to three phase matrix converter (MC) fed induction motor drive prototype is implemented using DSP based controller and tests have been carried out to evaluate and improve the stability of system under typical abnormal conditions. Digital storage oscilloscope & power quality analyzer are used for experimental observations.

• Journal of Electrical Engineering and Technology
• /
• v.6 no.3
• /
• pp.423-430
• /
• 2011

Multi-input multi-output (MIMO) dynamic matrix control (DMC) technique is applied to control steam temperatures in a large-scale ultrasupercritical once-through boiler-turbine system. Specifically, four output variables (i.e., outlet temperatures of platen superheater, finish superheater, primary reheater, and finish reheater) are controlled using four input variables (i.e., two spray valves, bypass valve, and damper). The step-response matrix for the MIMO DMC is constructed using the four input and the four output variables. Online optimization is performed for the MIMO DMC using the model predictive control technique. The MIMO DMC controller is implemented in a full-scope power plant simulator with satisfactory performance.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.3
• /
• pp.627-631
• /
• 2009

This paper presents a novel current steering cell matrix DAC(digital-to-analog converter) architecture to reduce decoder area. The current cell matrix of a existing architecture is selected by columns and lows thermometer code decoder of input bits. But The current cell matrix of a proposal architecture is divided 2n by the thermometer code decoder of upper input bits and are selected by the thermometer code decoder of middle and lower input bits. Because of this configuration, decoder numbers have increased. But the gate number that composed of decoder has decreased. In case of the designed 8 bit current steering cell matrix DAC, the gate number of decoder has decreased by about 55% in comparison with a existing architecture.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.15 no.3
• /
• pp.199-206
• /
• 2010

Matrix converter is an energy conversion device of controlled power semiconductor switches that directly connects the three-phase source to the three-phase load. With no dc-link components for energy storage in the matrix converter the input current depends directly upon the load currents and the switch state of the converter. Therefore the unbalanced and distorted input voltages can result in unwanted output harmonic currents. This paper presents a current compensator based on neural network to improving output current quality for matrix converter under abnormal input voltage conditions. The effectiveness and feasibility of the proposed technique has been proven through numerical simulations and experimental tests.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.25 no.2
• /
• pp.152-155
• /
• 2020

This study proposes an input filter for a gallium-nitride-based direct matrix converter with a stepless current commutation technique. Various current commutation strategies have been adopted for reliable operation of switches. These strategies are complex to be implemented and require additional components. The stepless current commutation technique is simple to operate but causes overcurrent issues due to the occurrence of short circuit on input sources. In this study, to restrict the short circuit current, we utilized GaN devices with fast switching properties and modified the input filter. The proposed input filter was verified by experimental results of induction motor drive.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.23-26
• /
• 2005

This paper describes the design, construction and implementation of matrix converter based on space vector modulation technique. The matrix converter provides sinusoidal input and output wave forms, bidirectional power flow, controllable input power factor and a compact design, compared to the VSI with diode rectification stage at the input. The implemented prototype of matrix converter is built using the exclusive IGBT module and has an input filter, overvoltage protection circuit and commutation means for overcoming practical issues. The good results tested using an induction motor are also presented.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.178-179
• /
• 2017

Input filter is an essential component in a practical matrix converter (MC) system to generate the sinusoidal input currents. However, the input filter causes a displacement angle between the input current of MC and the source current. In this paper, we investigate the input filter design for MCs by considering the displacement angles of the input current and the input voltage to guarantee high input power factor (IPF) operation as well as low input current harmonic contents. Simulation results are provided to validate the input filter design with near unity input power factor and low total harmonic distortion (THD) of the input current.

• Journal of the Korean Data and Information Science Society
• /
• v.20 no.6
• /
• pp.1207-1212
• /
• 2009

Basic objective in cluster analysis is to discover natural groupings of items or variables. In general, clustering is conducted based on some similarity (or dissimilarity) matrix or the original input text data. Various measures of similarities (or dissimilarities) between objects (or variables) are developed. We introduce a real application problem of clustering procedure in SPSS when the distance matrix of the objects (or variables) is only given as an input data. It will be very helpful for the cluster analysis of huge data set which leads the size of the proximity matrix greater than 1000, particularly. Syntax command for matrix input data in SPSS for clustering is given with numerical examples.