Unity Power Factor Control Research Articles

Comparison of three-phase inverter modulation techniques: a comprehensive analysis of SPWM and SVPWM

With the increasing utilization of renewable energy sources like solar and wind, three-phase inverters have become indispensable equipment for grid-connected energy systems, sparking significant research interest in the field of power electronics. This paper presents a comprehensive comparison of two primary modulation techniques employed in three-phase inverters: Sinusoidal Pulse Width Modulation (SPWM) control and Space Vector Pulse Width Modulation (SVPWM) control. The aim is to elucidate their respective advantages and disadvantages, particularly focusing on their performance under various control models. Through a systematic analysis of parameters such as total harmonic distortion under different control schemes including the unity power factor control model, the V/F control model, and the modulation ratio, this paper delves into the operational principles, strengths, and weaknesses of SPWM and SVPWM. Additionally, it elucidates the distinctions between these two modulation techniques and their interconnections. Lastly, the paper provides insights into the future development prospects and identifies potential technical challenges in the realm of pulse width modulation techniques.

Design and Performance Analysis of Ultra-Wide Bandgap Power Devices-Based EV Fast Charger Using Bi-Directional Power Converters

A widespread introduction of electric vehicles would require an advanced enriched fast-charging infrastructure and battery technology. Currently used silicon (Si) based power electronic devices limit their efficiencies, power density, and switching frequency. Designing fast-charging stations using these materials is not suitable due to low breakdown potential, less thermal stability, and less power handling abilities. The research will propose an off-board DC high-power density fast charging infrastructure with grid tie application. The EV station is designed by using ultra-wideband gap (UWBG) material-based power electronic devices to charge the EV vehicles in a few minutes up to an acceptable state of charge. The study will analyze the characteristics of Gallium III oxide (Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) material power devices by modeling them using SPICE and TCAD software tools. The research presents the Simscape physical modeling of electric vehicle chargers based on Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> power devices. Design analysis of three-phase bidirectional AC/DC converter and DC/DC isolated full bridge converter is present in this paper. Research implements the unity power factor control to improve the power quality requirements of the power grid. The dual active power control of converters provides a wide range of charging power for a variety of EV batteries. The study will provide high current and reliable rapid charging for currently available and upcoming future electric vehicles.

Field-Oriented Control of Five-Phase Induction Motor Fed From Space Vector Modulated Matrix Converter

This paper presents the field-oriented control (FOC) of a five-phase induction motor (FPIM) fed from a three-to-five phase direct matrix converter (DMC). The article focuses on the modulation and control of the three-to-five phase DMC, which discusses minimizing the problems associated with switching vector selection, sector identification, switching sequence selection, and dwell-time calculations. The DMC is controlled from the space vector pulse width modulation (SVPWM) technique, eliminating the x-y components of space vectors. Moreover, the matrix converter can perform unity power factor control at the input side. The FPIM is sourced from a DMC, and the FOC technique is applied to control the drive. The dynamic characteristics of the drive are succeeded for different loading conditions. The proposed work is simulated in Simulink/Matlab environment and further verified through practical experimentation. The control signals of the IGBTs are generated through FPGA embedded in dSPACE 1006. The experimental and the simulation results prove the practicability of the FOC to FPIM fed from a DMC.

Capabilities and incapabilities of unity power factor control algorithm for DSTATCOM under abnormal grid and load conditions

Capabilities and incapabilities of unity power factor control algorithm for DSTATCOM under abnormal grid and load conditions

Capabilities and incapabilities of unity power factor control algorithm for DSTATCOM under abnormal grid and load conditions

Capabilities and incapabilities of unity power factor control algorithm for DSTATCOM under abnormal grid and load conditions

Vibrating Coordinates Frame Transformation Based Unity Power Factor Control of a Three-Phase Converter at Grid Voltage Imbalance and Harmonics

This article proposes a control system of a three-phase grid-connected power converter, operating in the rectifier mode, which achieves the unity power factor target, i.e., unbalanced and distorted current instead of sinusoidal one for grid voltage imbalance and harmonics. Such a target is known from active power filters control, but it has not been used for power supply devices yet. Thanks to that, the three-phase converter is seen as resistive load by the utility grid, and active power is consumed with minimal possible rms current, keeping current asymmetry corresponding to the voltage asymmetry during unbalanced dips. Intentional introduction of current harmonics is not trivial from the point of view of both reference signals calculation and control system structure, because in the classical approach, it would require resonant terms in controller structure. Additionally, grid voltage asymmetry introduces another oscillating component, which imposes other resonant terms in the controller. The transformation presented in this article allows to achieve desirable current harmonics and asymmetry with the use of two proportional-integral controllers, one in each controlled axis. This article presents theoretical principles of the new transformation, control system structure as well as simulation and experimental tests of a three-phase converter utilizing this idea.

Design of Control System Using Online Tuning of PI Controllers for Three-Phase Active Front End Neutral Point Clamped Three-Level Converter

In conventional DC link AC-AC converter system, uncontrolled front end converter has inherent problem of power quality. To overcome the problem associated with uncontrolled front end converter, multilevel front end converter will be good choice for high power applications. In the paper, unity power factor control system (UPC) for active front end (AFE) neutral point clamped (NPC) 3-level converter is presented. PI controllers are used in UPC and for tuning of PI controllers it is essentially required to know the different time constants with their gains exactly for evaluating the optimized controller parameters for steady operation of the NPC rectifier. In this paper a simplified and accurate method of online tuning of PI controllers in UPC is derived and implemented for three phase AFE NPC 3-level converter. Complete design procedure for the design of control system for AFE NPC 3-level is also presented in this paper. Based on developed model, simulations are carried in MATLAB/SIMULIK environment. Experimentation results confirm the simulation results.

Concurrent unity power factor and constant mutual flux control for PMSG-WT MPPT

In this paper, a new concurrent unity power factor and constant stator flux linkage (UPF-CFL) control is presented. The main goal of this technique is to introduce the Permanent Magnet Synchronous Generator (PMSG) as an optimal wind energy transducer. The handled generator load angle and back EMF control achieve the optimum requirements for wind applications namely Maximum Power Point Tracking (MPPT). To do this, both UPF and CFL are integrated into one control methodology to obtain the advantages of each one. While the first well utilizes the apparent power increasing the generator side converter capability, the second protects the generator against magnetic saturation to enable higher speed operation. Mathematical model based on constant current fed equivalent circuit is presented taking the constraints of each individual control algorithm into account. The concurrent performance characteristics are presented and compared with each of concurrent separated algorithm characteristics for assessments. The control technique is implemented and finally, simulation testing is provided for evaluation.

A Day and Night Operational Quasi-Z Source Multilevel Grid-Tied PV Power System to Achieve Active and Reactive Power Control

A day and night operational single-phase energy stored quasi-Z-source-cascaded H-bridge (ES-qZS-CHB) inverter photovoltaic (PV) power system to achieve the active and reactive power control is proposed in this article. The ES-qZS-CHB inverter PV power system usually employs the unity power factor control method to ensure the output current tracking the desired reference in phase with the grid voltage, combining with distributed maximum power point tracking (MPPT) to determine the values of shoot-through duty ratios Dn. These cannot operate at night because there is no PV power input. Meanwhile, as multiple combinations of Dn and modulation ratio Mn could achieve the same voltage gain at night operation, but which is optimal has not been addressed. This article proposes a solution to address these issues. First, a comprehensive control scheme, which not only has the attractiveness of day and night operation but also shows the advantage of active and reactive power control simultaneously, is proposed; then, an optimization control method is proposed for night operational ES-qZS-CHB inverter to achieve optimal combination of Dn and Mn. Simulation and experimental results validate the day and night operational ES-qZS-CHB inverter and the proposed optimal control technique.

Unit Template Based Control of PV-DSTATCOM

Background: In modern electrical power distribution systems, Power Quality has become an important concern due to the escalating use of automatic, microprocessor and microcontroller based end user applications. Methods: In this paper, power quality improvement has done using Photovoltaic based Distribution Static Compensator (PV-DSTATCOM). Complete simulation modelling and control of Photovoltaic based Distribution Static Compensator have been provided in the presented paper. In this configuration, DSTATCOM is fed by solar photovoltaic array and PV module is also helpful to maintain the DC link voltage. The switching of PV-STATCOM is controlled by Unit template based control theory. Results: The performance of PV-DSTATCOM has been evaluated for Unity Power Factor (UPF) and AC Voltage Control (ACVC) modes. Here, for studying the power quality issues three-phase distribution system is considered and results have been verified through simulation based on MATLAB software. Conclusion: Different power quality issues and their improvement are studied and presented here for harmonic reduction, DC voltage regulation and power factor correction.

Unity power factor control of permanent magnet synchronous motor by using open winding configuration

This paper presents the performance of open-winding permanent magnet synchronous motor (OW-PMSM). It mainly includes vector modulation technology considering the unity power factor control.And a topology structure is proposed to optimize the fault tolerance of inverter. Matlab software and Maxwell software collaborative simulation are supplied to obtain the reactive power, speed, terminal voltage, electromagnetic torque etc. under normal and fault status. Finally, the simulation results of an open-winding permanent magnet synchronous motor are verified by the experimental results.

DSTATCOM for Harmonic Mitigation in Distribution Lines using Two-Level Inverter

Distribution systems have been facing serious problems of harmonics load current mainly due to advancement in power electronic based and other non-linear loads. The DSTATCOM has been widely used to mitigate the load current harmonics problems in distribution system. The power quality improvement is one of the major problems when the distribution side load increases with non-linear loads like electric vehicles, laptops, PCs etc., There are some power quality mitigation technique available at the load side where the electronic chargers works with unity power factor (UPC) control. But many DC loads are connected without the UPC. So, it is a need for a device which corrects the real and reactive power at the distribution level. The DSTATCOM is connected to the Indian distribution system with 415V, 50Hz. In this paper the linear loads and nonlinear loads are coupled to the system and analysis with DSTATCOM and without DSTATCOM cases are presented.

Unity power factor control for surface mounted permanent magnet synchronous generator (PMSG) based on polar coordinate current locus

This paper proposes a unity power factor control for PMSG based on current angle, which replaces the conventional id-iq plane with polar coordinate. The polar coordinate takes the current angle as polar angle and the phase current magnitude as polar radius. The method presented simplify the UPF current locus for PMSG, therefore, the design process of UPF control strategy was simplified. As verification to the proof-of-concept, a simulation model is developed, and also a hardware prototype of a PMSG generation system is constructed and test up to 320kW. The experimental results show that a power factor of 0.9812 with the UPF control method proposed.

DSP in the Loop Implementation of a Backstepping Controller for Wind Energy Conversion System Based on a Doubly Fed Induction Generator Connected to Grid

This paper deals with the design and implementation of the control strategy of a grid connected Doubly Fed Induction Generator wind turbine on a TMS320F28335 Digital Signal Processor (DSP). The synthesized controller is a nonlinear Backstepping control law whose stability is guaranteed in the context of Lyapunov stability theory. The control aim is to optimize the power extracted by the generator for large wind speed variations through Maximum Power Point Tracking (MPPT) and Unity Power Factor (UPF) control. These command strategies are implemented in order to achieve the following specifications: good static precision for optimal energy conversion; electrical dynamics as high as possible regardless of slow mechanical dynamics, smooth transient without overshoots that could damage the lifecycle of the machine and converters, rapid disturbance isolation and robustness to any parametric variations or uncertainties. The results of the Hardware in the Loop (HIL) implementation on DSP show satisfactory performance in terms of response time, setpoint tracking, stability, and robustness under stochastic wind speed profile and parameter variations.

An Effective Charging-Torque Elimination Method for Six-Phase Integrated On-Board EV Chargers

This paper proposes an effective charging-torque elimination method for six-phase integrated on-board electric vehicle (EV) chargers. The integrated EV charger is derived from the power inverter, motor windings, sensors, and microchips, which can significantly reduce the system cost and volume. In fact, the charging electromagnetic torque is inevitable to produce, since the alternating currents flow through the motor windings. This is due to the motor windings serving as the filtering inductors of the rectifier for the on-board charger. In order to keep the vehicle standstill during the charging process, a universal expression of charging torque is derived and analyzed, which is according to magnetic co-energy approach. All possible charging torque elimination positions are presented with a numerical method. Moreover, the unity power factor and zero sequence current control are executed during the EV charging process. Finally, the proposed charging torque elimination method is verified by both simulation and experimentation. The results prove the validity of the proposed charging-torque elimination method for six-phase permanent magnet synchronous machine.

Optimized Modeling and Control Strategy of the Single-Phase Photovoltaic Grid-Connected Cascaded H-bridge Multilevel Inverter

This paper presents the modeling and control-loop design method with an inverted decoupling scheme of a single-phase photovoltaic grid-connected five-level cascaded H-bridge multilevel inverter. For the unity power factor, the proportional and integral current controller with a duty ratio feed-forward compensation is used. In addition, in order to achieve the maximum power point tracking of each photovoltaic array, when the stacked modules are in the partial shading condition, each direct current (DC) voltage is stably controlled to their maximum power points (MPP) by dedicated voltage controllers of each H-bridge module. This paper also presents a control method that minimizes the effect of the loop-interaction in the design of an individual DC-link voltage control loop in a two-input two-output system. The proposed control methods of the cascaded H-bridge multilevel inverter are validated through the simulation and experimental results of the 2-kW prototype hardware.

UPC strategy and implementation for buck–buck/boost PF correction converter

Nowadays, low power factor (PF) is a serious problem that has gained more importance in power electronics area. In this study, a unity PF control (UPC) strategy for boundary conduction mode (BCM) buck–buck/boost PF correction converter is proposed. The proposed control strategy can achieve high PF and low total harmonic distortion by utilising the input and output voltages to modulate the on-time of both buck and buck/boost switches. The operating principles and comparative analysis of BCM buck–buck/boost converter with conventional non-UPC and UPC are analysed. For verifying the effectiveness of the proposed control strategy, the experimental verifications are carried out from a 100 W universal input prototype.

Effective power transfer scheme for a grid connected hybrid wind/photovoltaic system

A new topology and effective power transfer scheme with minimum number of converters is proposed for a grid connected wind/photovoltaic (PV) system. Distributed generation sources considered are permanent magnet synchronous generator (PMSG)-based wind energy conversion system and PV array system. Two voltage source converters with a common DC-link serve as wind side converter (WSC) and grid side converter (GSC), respectively. The PV array is directly tied to the DC link without any power converter providing variable DC-link voltage. The Perturb and Observe technique extracts the maximum power from PV and the DC-link voltage is set to the maximum power point (MPP) voltage of the PV array. The output DC voltage of WSC is regulated to an MPP PV voltage using an outer proportional–integral voltage control loop. The maximum power from the PMSG and stator voltages is utilised to generate the reference currents for WSC to make stator currents to follow stator voltages. With unity power factor control, the overall VA of the WSC would contribute to the active power transfer and thereby reduce the kVA rating of the WSC in the proposed configuration. GSC tracks the maximum power from wind and PV array, and serves as a shunt active power filter to compensate for the current unbalance due to the connection of non-linear loads at the grid. All these functions are accomplished simultaneously. Various power transfer modes of operation are simulated through MATLAB/Simulink software and its results are validated through dSPACE Digital Signal Processor.

Simulation Study of Three - phase PWM Rectifier with Square of the Voltage Double Closed Loop Control

Based on the rotating coordinate system model, the mathematic analysis of the three-phase voltage-sourced PWM rectifier is carried out, and its feed-forward decoupling control strategy is studied. In order to realize the fast response of DC voltage and improve the dynamic and static performance of the rectifier, the double-closed-loop control of outer square of voltage loop and inner current loop is established. The control system of three-phase voltage-sourced PWM rectifier based on space vector modulation algorithm is designed. The simulation results demonstrate the designed model is accurate, and can achieve unity power factor control, DC voltage fast responses, and has not steady-state error.

Double-ended Synchronous Reluctance Motor Drive with Extended Constant Power Speed Ratio and Increased Power Factor

This article proposes a double-ended synchronous reluctance machine drive to increase the constant power speed ratio and the power factor of a synchronous reluctance machine. The proposed double-ended synchronous reluctance machine drive is formed by two inverters, one connected to an energy source and the other one connected to a floating capacitor bank for reactive power compensation. Two control strategies are presented: the unity power factor control can keep the power factor unity seen from the energy source side inverter under all operating conditions; the optimum inverter utilization control can increase torque output ability and the constant power speed ratio while increasing the power factor. Detailed modeling and simulation of the proposed double-ended synchronous reluctance machine drive are presented. Compared to the traditional single-inverter synchronous reluctance machine drive, the proposed drive is able to reduce the conversion ratio of the front-end DC/DC converter and the rating of each switching device. In addition, three-level voltage output of the proposed drive is also capable to reduce total harmonic distortion. In conclusion, the proposed drive is very attractive for applications for which a high power factor or reactive power regulation is required or when a high constant power speed ratio is desired.