Three-phase

About: Three-phase is a research topic. Over the lifetime, 16801 publications have been published within this topic receiving 159477 citations.

Output Voltage Control of A Four-Leg Inverter Based Three-Phase UPS by Means of Stationary Frame Resonant Filter Banks

Abstract: A method for high performance output voltage control of a four-leg inverter (FLI) based three-phase UPS is proposed Stationary frame resonant filter bank based output voltage control loop, which is complemented by capacitor current feedback based active damping loop, is employed Utilizing the zero-state partitioning variable, a generalized form of scalar PWM for the FLI is developed and the minimum loss discontinuous PWM method is derived The controller and modulator design and implementation details for the FLI-UPS are given Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered The scalar control and PWM methods are proven by means of theory, simulations, and experiments

Positive and negative sequence estimation for unbalanced voltage dips

Abstract: This paper proposes the use of a complex Kalman filter for the estimation of positive and negative sequences from three phase voltages. A complex voltage is obtained by applying the /spl alpha//spl beta/-transform followed by the dq-transform using a rotational operator. The algorithm for three phase voltages containing K harmonics is also given. In the conventional method, estimation of positive and negative sequences is performed through two steps: the magnitude and phase-angle in each individual phase of the voltages are first estimated and the symmetrical component transformation is then applied. The proposed method offers a direct estimation of the positive and negative sequences that may reduce the estimation errors. In addition, the proposed method has a reduced computational cost since the number of state variables is reduced to 2/3 as compared to that in the conventional method. An experiment was performed on measured three phase voltage data. Results have shown that the proposed method offers a good estimation.

Phase Current Reconstruction and Control of Three-Phase Switched Reluctance Machine With Modular Power Converter Using Single DC-Link Current Sensor

Abstract: According to the modular power converter, a novel phase current reconstruction method using single dc-link current sensor is proposed for three-phase switched reluctance machine (SRM), and the control method is implemented with the reconstructed phase current as well. A highly integrated modular power converter is constructed by a three-phase full bridge and a dual switch module. The phase windings are in star-connection, and the bipolar phase currents are applied. Based on the special operating modes and single pulse width modulation signal injection, the dc-link current is decoupled and the phase current in both magnetization and demagnetization regions is reconstructed, which is very critical for the implementation of some advanced methods that require complete period phase current. The conventional control methods of the SRM, such as single-pulse voltage and hysteresis current control methods, are carried out under different operating conditions with both simulation and experiment to verify the effectiveness of the proposed method, and the reconstruction errors and performance influences are detailed analyzed as well.

A five/nine-level twelve-switch neutral point clamped inverter for high speed electric drives

Abstract: A twelve-switch, three phase, five/nine level inverter is presented for applications using a high speed electric machine with a relatively low per-unit leakage reactance By reducing the voltage blocking requirement of the semiconductors, the neutral point clamped variant of the coupled inductor inverter topology (NPC-CI) is more suited to high DC bus voltages, and features a significant reduction in magnetic material required over six-switch coupled inductor inverters This paper describes the operational and design techniques for the NPC-CI inverter A simple continuous PWM technique for operation with a three-limb core is presented and the specific design challenges involved in the NPC-CI inverter are highlighted: designing the three-limb coupled inductor, the natural balancing action of the split-dc link, semiconductor stresses, inverter construction and practical considerations for inverter operation of the drive Machine performance is then illustrated on an unloaded 18,000 rpm 15HP induction machine to emphasize the harmonic quality improvement, and on a loaded 2HP utility speed induction machine to demonstrate transient performance

Three-Phase Series Resonant DC-DC Boost Converter With Double LLC Resonant Tanks and Variable Frequency Control

Abstract: This paper proposes a three-phase inverter combined with two LLC resonant tanks series resonant DC-DC boost converter with variable frequency control. The three-phase inverter side of the proposed circuit is connected to identical two-level LLC tanks to ensure balanced resonant currents. The proposed converter requires less switching devices and transformers as compared to the conventional interleaved LLC resonant converter, which competitively offers higher efficiency and reduced size and cost. Furthermore, the proposed converter works above the resonant frequency to achieve zero voltage switching (ZVS) for the entire operating frequency range ${(42.5kHz for all switches. Variable frequency controller is considered in order to obtain better stability for diverse loads. Therefore, the proposed converter will have the ability to respond to the load changes by varying the switching frequency to the value that fulfils the requirement. In order to verify the improvement of the proposed converter, the converter performance is compared to conventional interleaved LLC resonant converter. The theoretical outcomes are confirmed through simulation studies using MATLAB/SIMULINK and validated experimentally using a laboratory prototype. Selected results are presented to verify the effectiveness of the proposed converter.