Source Inverter Type Research Articles

PERFORMANCE ANALYSIS AND SPEED CONTROL USING INDIRECT VECTOR CONTROLLED FOR INDUCTION MOTOR DRIVES

This paper presents the speed control scheme of an indirect vector-controlled induction motor (IM) drive. PWM controlling scheme is based on Voltage source inverter type space vector pulse width modulation (SVPWM) and the Conventional-PID controller or Fuzzy-PID controller is employed in closed-loop speed control. Decoupling of the stator current into torque and flux producing (d-q) current components model of an induction motor is involved in the indirect vector control. The torque component Iq current of an IM is developed by an intelligent-based Fuzzy PID controller. Based on settling time and dynamic response the performance of the Fuzzy Logic Controller is compared with that of the PID Controller to sudden load changes. It provides better control of motor torque with high dynamic performance. The simulated design is tested using various toolboxes in MATLAB. Simulation results of both controllers are presented for comparison.

Reactive power control of grid-connected photovoltaic micro-inverter based on third-harmonic injection

<span lang="EN-US">This paper presents four interleaved flyback DC-DC converters. Each flyback converter contains a separate maximum power point tracker (MPPT). The MPP tracker is used to collect the maximum power value from photovoltaic panel by using (P&O) algorithm with an output of reference current. In latest years, the active third-harmonic injection circuit have received much interest, this technique contributed to getting a better quality of injection current into the utility grid and control the reactive power. For converting direct current to three-phase sinusoidal currents, a line-commutated current source inverter type (CSI) with filter is used. The developed micro-inverter of (1000 W) offers an expanded range of reactive power control with balanced three-phase output power and good efficiency 95.07%. The effectiveness of the suggested system is clarified through the MATLAB program simulation. The system proposed in this paper has proven its effectiveness in obtaining reactive power control, nearly sinusoidal three-phase output currents and it is compared with the traditional PV micro-inverter system. The comparison shows that the PV micro-inverter is best in more specification than the traditional PV system such as efficiency and total harmonic distortion (THD) and the system losses.</span>

REACTIVE POWER CONTROL OF THREE-PHASE MODULE INTEGRATED PV MICRO-INVERTER BASED ON BOOST CONVERTER

In recent years, photovoltaic power generation has become a creative technology. This technology uses solar energy to overcome the energy shortages in modern power systems because of increasing environmental problems in traditional power generation systems. It has irreplaceable benefits like pollution reduction and has increasingly been turned into a new path for distributing power generation applications. In traditional PV system design to produced enough DC-bus voltage from PV panels, several PV modules are connected in series connection. However, when certain modules are partially shadowed, the overall power generation of the PV panels often falls significantly, reducing its essential current generation and preventing the output current from reaching its maximum value within that panels. An AC modules strategy was suggested in this paper to solve this drawback. The PV system with an interleaved DC-DC boost converter and maximum power point tracker (MPPT) for each boost converter is used in the DC-DC converter stage. The perturbation and observation (P&O) algorithm is applied to extract sun power. In this paper, a three-phase micro-inverter voltage source inverter type (VSI) of 1000W is designed and simulated. By controlling the direct and quadrature components of inverter output currents, the active and reactive power can be injected into the grid. The system is simulated using MATLAB software and the simulation results show the validity of the suggested Micro-inverter system.

Performance Comparison of Reactive Power Control Methods of Photovoltaic Micro-inverter

Photovoltaic power generation becomes an important technology in recent year, because of its advantages such as clean energy, pollution reduction, no gas emissions, maintenance and operation requirements are low. So it is a new path for generating electric power. This paper will study the performance comparison of two photovoltaic systems of three-phase grid-connected micro-inverter and study their design methods of reactive power control. The first design is suggested that the photovoltaic PV system based on an interleaved DC-DC boost type converter with its maximum power point tracking control (MPPT) for each boost converter. A voltage source inverter type (VSI) is used as a three-phase micro-inverter. By controlling the direct and quadrature components of inverter output currents, reactive power controlling is achieved at 90.76% efficiency. The second design is suggested that the photovoltaic panel is connected DC-DC converter of an interleaved flyback type. Each sub-converter is controlled by an individual (MPPT). The circuit of active third-harmonic current injection in recent years have received much interest, this technique contributed to get better quality of current injected into the utility grid and to control the reactive power with good efficiency 95.07%. A line-commutate current source inverter type (CSI) with filter is used. The developed micro-inverter of (1000W) offers an expanded range of reactive power control with balanced three-phase output power. Each system design in this study has proven its effectiveness in obtaining control of reactive power and nearly sinusoidal three-phase output currents. The effectiveness of the suggested systems are clarified by using the MATLAB Simulink program and the results of the simulation show the validity of the suggested micro-inverter system.

Effective Power quality improvement using Dynamic Activate compensation system with Renewable grid interfaced sources

Abstract Rapid Industrialization and demand for Energy makes the distribution system more complicated. To address such issue robust control system is being developed for newly implemented microgrid and smart grid concepts. These control systems being a complex structure interconnects the renewable sources with the conventional sources of energy production. The power quality issues arising due to interconnection of number of variable generation system makes it more dynamic and fault oriented. The dynamics of the system is due to the use of power conditioning unit in the renewable system. Most of the power conditioning unit are of current source inverter type. However if these inverters can be made up of voltage source type then reactive power compensation can be achieved in addition to the active power supplied by the inverter into the grid. Dynamic Active Compensation System (DACS) is simulated through MATLAB to validate the performance.

Sensorless Control Technology for PMSG base on the Dead-time Compensation voltage

In order to improve the speed sensorless-control system of PMSG in low speed performance, this paper introduces a novel Dead-time compensation control method .Mathematical model is established according to the Dead-zone of the influence of the voltage source type inverter output voltage. At the same time, the given value of current regulator output voltage has been fixed based on the established model. Then the stator voltage after compensationed is applied to the flux estimation, which improves the performance of flux estimation. Finally, the position and speed of the rotor is estimated based on Back-Electromotive Force, which has Simple algorithm and good robustness. In order to verify the correctness of theoretical analysis, the experiment was done according to the new control method. The results proved the correctness and feasibility of this control method.

Linearization Approach for Modeling Power Electronics Devices in Power Systems

Power electronics devices are extensively used in renewable energy resources, modern power grids, and industrial facilities. In this paper, a linearization approach is proposed as a generic dynamic modeling method for power electronics devices in power systems. The associated control system is included in the modeling. This approach can be readily used for renewable energy resources, such as wind turbines and solar photovoltaic systems, and for power electronics devices in power systems, such as variable frequency drives (VFDs). The developed dynamic models are suitable for power systems dynamic studies. To demonstrate the effectiveness of the proposed approach, the dynamic load model of a system, consisting of a voltage source inverter type low-voltage six-pulse VFD and an induction motor, is developed in this paper, and a sample motor drive system is provided as a case study to verify the accuracy of the developed dynamic load model.

Output Voltage Correction for a Voltage Source Type Inverter of an Induction Motor Drive

A proposed voltage error correction method that uses a disturbance observer for various types of induction motor control was evaluated. The features of the proposed control method are: 1) control parameters are easily determined according to the motor model and the parameter sensitivity is robust, and 2) the proposed method can be applied for field-oriented vector control, speed sensor-less vector control, and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> / <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> control of the induction motor by modification of a back electromotive force compensation term in the observer. The disturbance observer is designed to have fast response that is ten times faster than the current controller for vector control. The voltage error is efficiently corrected using the proposed method, and the current distortion can be reduced by approximately 1/3. The proposed method is validated on the basis of experimental results.

Implementation of a Fuzzy PI Controller for Speed Control of Induction Motors Using FPGA

This paper presents the design and implementation of voltage source inverter type SVPWM based speed control of an induction motor using a fuzzy PI controller. This scheme enables us to adjust the speed of the motor by controlling the frequency and amplitude of the stator voltage; the ratio of the stator voltage to the frequency should be kept constant. A model of the fuzzy control system is implemented in real time with a Xilinx FPGA XC3S 400E. It is introduced to maintain a constant speed to when the load varies.

Current Control for Single-Phase Active Filter Based on Multirate PWM

The shunt active filter, which is connected to power systems in parallel with the load, is considered as a current source. However, the shunt active filter is actually realized by current control using the voltage source type inverter. Authors applied multirate perfect tracking control (PTC) to current control for the shunt active filter. Although conventional single-rate deadbeat control could not guarantee zero tracking error for arbitrary reference signals, the proposed multirate control can achieve perfect tracking at every sampling point. In this paper, we propose a novel method to generate repetitive compensation signals. Simulations and experiments are shown to verify the effectiveness of the proposed method.

Newly proposed hybrid resonant commutation bridge-leg link snubber-assisted three-phase ZVZCS-PWM soft-switching inverter

This paper presents the newly proposed hybrid resonant commutation bridge-leg link (HRCB) snubber circuit which can achieve zero voltage and zero current soft-switching commutation for single-phase and three-phase voltage source-type inverter, along with its unique features and operation principle. The circuit parameter design approach for the HRCB snubber circuit and the determination estimating scheme of the gate pulse timing processing which is more suitable and acceptable for single-phase and space voltage vector modulated three-phase voltage source inverter using the HRCB snubber circuit are described in this paper. In particular, the three-phase voltage source soft-switching inverter associated with the proposed HRCB circuits are evaluated and discussed from simulation and experimental viewpoints. The practical effectiveness of the HRCB snubber-assisted three-phase voltage source soft-switching inverter using IGBT power modules which is based on the instantaneous space voltage vector modulation is clarified on the output voltage waveform, actual efficiency of electromagnetic noise in comparison with three-phase voltage source-type conventional hard-switching inverter. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 75–84, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20111

A novel method for active filter current regulation using deadbeat control

AbstractThe shunt‐type active filter (AF), which is widely used due to its protection capability, is installed in parallel to the load. It is considered as an ideal current source and it compensates the harmonic current of the load. However, the AF is practically realized by a current regulator using a voltage source‐type inverter, and it is very difficult to realize the AF current as an ideal current source, especially when it is controlled by digital equipment.A new control scheme for a line current detection AF is proposed to improve the current regulation capability based on digital deadbeat control. The current control scheme is achieved by controlling the intermediate voltage of the inverter output filter so that the AF output current is regulated, using the dead‐beat control law for the calculation of the pulse width of the PWM inverter. In the proposed scheme, the current regulation performance is much better than in the conventional one.The control method, mathematical analysis, simulation results, and experimental results are presented in this paper. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(2): 67–77, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10201

A Novel Method for Active Filter Current Regulation using Dead-beat Control

The shunt-type active filter (AF), which is widely used due to the protection capability, is installed in parallel to the loads. It is considered as the ideal current source and it compensates the harmonic current of the load. However, the AF is practically realized by the current regulator using the voltage source type inverter, and it is very difficult to realize the AF current as an ideal current source, especially when it is controlled by the digital equipments.A new control scheme for the line current detection type AF is proposed to improve the current regulation capability based on the digital dead-beat control. The current control scheme is achieved by controlling the intermediate voltage of the inverter output filter so that the AF output current is regulated using the dead-beat control law for the calculation of the pulse width of the PWM inverter. In the proposed scheme, the current regulation performance is improved much better than the conventional one.The control method, mathematical analysis, the simulation results and the experimental results are presented in this paper.

Analysis of common mode voltage-"neutral shift" in medium voltage PWM adjustable speed drive (MV-ASD) systems

In this paper, an analysis of common mode voltage or "neutral lift" in the new emerging voltage source inverter type medium voltage adjustable speed drive (MV-ASD) systems is presented. Both cascaded multilevel (CML) inverter and 3-level NPC inverter topologies are analyzed. An equivalent circuit model to determine the common mode voltage stress is presented. Analysis and simulation results are discussed and worst case common mode voltage excursion is computed for an example 800 hp, 4160 V MV-ASD. It is shown that certain system components are excessively stressed and in the MV-ASD system these data are particularly useful in specifying system components and for proper design of the system. Possible effects of common mode voltage and its dv/dt on medium voltage motor bearings are discussed. A new multilevel PWM strategy is introduced which results in zero common-mode voltage. Simulation results are shown to illustrate the effectiveness of these schemes. Finally, experimental results from a 800 hp, 4160 V, MV-ASD system are presented.

Harmonic and interharmonic distortion in current source type inverter drives

Current source inverter drives are sources of harmonic and nonharmonic distortion in supply systems. The nonharmonic components have frequencies that change with motor speed so conventional filters might not be effective in reducing their amplitude. The distortion calculation at the design stage allows preventive actions to minimise the distortion at source by varying DC link and/or AC motor parameters. The aim of the paper is to discuss the modeling of the supply side current distortion and to analyse the effects of nonideal supply conditions. The main utilizable models, both analogue and numerical, are discussed and analysed. Several laboratory and numerical experiments are reported to compare the different model characteristics and to analyse the current distortion sensitivity to the supply voltage distortion and unbalance. >

Fundamental Design and Electrical Characteristics of Superconducting Commutatorless Motor.

Since there are no iron cores in the rotor and stator windings of superconducting synchronous motors, some reactances are intrinsically smaller than the ones of conventional motors. So the low synchronous reactance would be expected to improve the torque-ampere ratio stability and the overload capacity in case of the variable speed drive system of a load commutated inverter due to the small armature reaction. Moreover, the low sub-transient reactance may contribute to lessen the voltage stress during the shortened commutating period, especially in current source type inverter (CSI) systems.In this paper, after presenting analytical formulas needed for a machine design, one design algorithm is described, citing one example of an experimental CSI fed superconducting motor of 30 kVA which will be fabricated. Further, the distinguished features in its operation, as expected just above, are verified by the computer simulation study in comparison with a conventional machine in terms of a high specific power density, an extension of stable power limit and so on.

Comparison of thyristor switched capacitor and voltage source GTO inverter type compensators for single phase feeders

The use of small static compensators for the control of voltage on single-phase distribution feeders is investigated. A candidate feeder system is examined to determine the size and type of reactive compensation required. A comparison is made of the single-phase design of a thyristor switched capacitor type compensator with an advanced gate turn-off thyristor voltage source inverter type of compensator. The advantages of the three-phase advanced compensator are not evident in the single-phase design.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Generalized Root-Loci Theory for the Static Scherbius Drive

Generalized root-loci techniques, developed in the mid 70's for squirrel cage motors, have been extended in the static Scherbius configuration to wound rotor, slip energy, recovery systems. This arrangement is now applied to large power drives in the 0.5 to 50 MW range. In this paper, general results applicable to all machines are presented for the open-loop control scheme, but only the subsynchronous rmode of operation in which a voltage source type inverter is used is addressed.