Three-phase Pulse Width Modulation Research Articles

Design and Implementation of Robust H∞ Control for Improving Disturbance Rejection of Grid-Connected Three-Phase PWM Rectifiers

In response to the high performance requirements of pulse width modulation (PWM) converters in grid-connected power systems, H-Infinity (H∞) control has attracted significant research interest due to its robustness against parameter variations and external disturbances. In this work, an advanced robust H∞ control is proposed for a grid-connected three-phase PWM rectifier. A two-level control strategy is adopted, where cascaded H∞ controllers are designed to simultaneously regulate the DC bus voltage and input currents even under load disturbances and non-ideal grid conditions. As a result, unit power factor, stable DC bus voltage, and sinusoidal input currents with lower harmonics can be accurately achieved. The design methodology and stability of the proposed controller are verified through a comprehensive analysis. Simulation tests and experimental implementation on a dSPACE 1103 board demonstrate that the proposed control scheme can effectively enhance disturbance rejection performance under various operating conditions.

Virtual Power Grid Flux-Oriented Vector Control for Three-Phase Voltage-Type PWM Rectifier

More considerable power distortions are produced by the non-reversible diode-bridge rectifiers in the power system’s AC-DC conversion technology. In addition, bridge-rectifiers worsen energy quality and decrease power factor. Three-Phase Pulse Width Modulation (3phase-PWM) rectifiers have seen rapid growth in use due to recent breakthroughs in power device technology. Its benefits include a unity power factor, no harmonic distortion, and pulsating direct currents. An actual power regulation technique based on a novel virtual power grid controller is suggested to cheaply regulate a 3phase-PWM converter with good performance. The study introduces a new sensorless control scheme to improve the 3phase-PWM-performance rectifier. The proposed control technique employs the virtual power grid flux-oriented vector control with a Second-Order Generic Integral with Instantaneous Phase Lock Loop (SOGI-IPLL) to overcome the problems inherent in relying only on low-pass filter estimates. The virtual power grid flux value may then determine the phase difference. The IPLL takes the phase angle as an input and is utilized to construct the power-oriented vector control. The proposed power grid flux-oriented control strategy combines the VFidea with SOGI-IPLL to circumvent the restrictions imposed by relying only on an integrator of low-pass filters (LPF) to provide an estimate. A refined Virtual flux (VF) estimator with direct power control can improve management at a cheaper cost and more efficiently. The modeling findings demonstrate that the DC voltage input and power grid throughput of the 3phase-PWM rectifier can be successfully regulated in both the rectification and inversion states, allowing for the effective functioning of the 3phase-PWM rectifier.

Model Predictive Based Direct Power Control Method Using Switching State Preference for Independent Phase Loss Decrease of Three-Phase Pulsewidth Modulation (PWM) Rectifiers

Model Predictive Based Direct Power Control Method Using Switching State Preference for Independent Phase Loss Decrease of Three-Phase Pulsewidth Modulation (PWM) Rectifiers

Integrated Control and Optimization for Grid-Connected Photovoltaic Systems: A Model-Predictive and PSO Approach

To propel us toward a greener and more resilient future, it is imperative that we adopt renewable sources and implement innovative sustainable solutions in response to the escalating energy crisis. Thus, renewable energies have emerged as a viable solution to the global energy crisis, with photovoltaic energy being one of the prominent sources in this regard. This paper represents a significant step in the desired direction by focusing on detailed, comprehensive dynamic modeling and efficient control of photovoltaic (PV) systems as grid-connected energy sources. The ultimate goal is to enhance system reliability and ensure high power quality. The behavior of the suggested photovoltaic system is tested under varying sun radiation conditions. The PV system is complemented by a boost converter and a three-phase pulse width modulation (PWM) inverter, with MATLAB software employed for system investigation. This research paper enhances photovoltaic (PV) system performance through the integration of model-predictive control (MPC) with a high-gain DC–DC converter. It improves maximum power point tracking (MPPT) efficiency in response to the variability of solar energy by combining MPC with the traditional incremental conductance (IN-C) method. Additionally, the system incorporates a DC–AC converter for three-phase pulse width modulation, which is also controlled by predictive control technology supported by Particle Swarm Optimization (PSO) to further enhance performance. PSO was selected due to its capability to optimize complex systems and its proficiency in handling nonlinear functions and multiple variables, making it an ideal choice for improving MPC control performance. The simulation results demonstrate the system’s ability to maintain stable energy production despite variations in solar irradiation levels, thus highlighting its effectiveness.

Suppression Strategy of Differential Mode Circulating Current in Parallel Three-Phase PWM Converter

Parallel three-phase pulse width modulation (PWM) converter is a useful technique for increasing the capacity of a power system, but it also introduces the issue of circulating current, which can cause an increase in the loss of power electronics (PE) switches and even lead to over-current, which can affect the overall performance of the system. In this paper, a strategy is proposed for suppressing the differential mode circulating current (DMCC) in each phase of the parallel converter, which is less dependent on system parameters. Based on the mathematical model of the parallel converter, the relationship between the PWM duty cycle and circulating current is derived, which provides a basis for adjusting the switching operation of PE switches. This method requires no additional hardware and is simple to implement with a fast dynamic response. The simulation results verify the correctness of the theoretical analysis, and it can effectively achieve the balanced suppression of DMCC in each phase, which indicates that the method is suitable for the application scenario of parallel current sharing of multiple converters.

Finite-Time Adaptive Fuzzy Control for Three-Phase PWM Rectifiers With Improved Output Performance

For three-phase pulse width modulation (PWM) rectifiers, system uncertainties, such as load disturbances, parametric uncertainties, and grid disturbances, may result in significant DC-link voltage fluctuations, degrade the quality of grid currents, and even lead to system instability. To address this issue, a modified dynamic model of the PWM rectifier with system uncertainties is established, and a finite-time adaptive fuzzy control (FTAFC) method with the dual-loop structure is proposed. In the outer voltage loop, a finite-time adaptive law is used to maintain stable DC-link voltages despite load disturbances. In the inner power loop, an adaptive fuzzy technique is used to estimate and compensate system uncertainties, thus ensuring finite-time power tracking. It is confirmed that all signals of the closed-loop system are finite-time bounded. The experimental and simulation results demonstrate the effectiveness of the proposed method.

Sliding mode approach for control and observation of a three phase AC-DC pulse-width modulation rectifier

Introduction. For AC-DC conversion systems, the electrical systems typically use thyristor or diode bridge rectifiers, which have relatively poor performance. Nowadays, three-phase pulse-width modulation rectifiers are widely applied in various applications for their well-known intrinsic benefits, such as adjustable DC link voltage, unity power factor, bidirectional power flow and very low total harmonic distortion. Purpose. The objective of this work is to achieve better stability and dynamic performance using sliding mode strategy for control and observation. Methods. For that purpose, first a sliding mode controller is introduced on the DC-link side to ensure a fast and accurate response of the output load voltage. Then, the sliding mode approach is employed to control the quadrature and direct components of power to maintain the input power factor at unity. Finally, this approach is used to design two observers for grid voltage estimation and online variation of load resistance. To overcome the problem associated with the use of the classical low-pass filter, an adaptive compensation algorithm is used to compensate the attenuation of the amplitude and phase delay of the observed grid voltages. This algorithm is based on the use of the two low-pass filters in cascade and ensures the minimization of chattering. Results. Comparative studies have been carried out between sliding mode control method for controlling the three-phase AC-DC pulse-width modulation rectifier and other conventional techniques. The validation by simulation and the tests carried out gave very satisfactory results and proved the effectiveness and feasibility of the sliding mode for both control and observation of three phase pulse-width modulation rectifier.

Advanced Control of Three-Phase PWM Rectifier Using Interval Type-2 Fuzzy Neural Network Optimized by Modified Golden Sine Algorithm

Three-phase Pulse-Width Modulated (PWM) rectifiers used between the power grid and the load in applications requiring DC voltage have features such as high efficiency, high power factor, and low harmonics. This paper proposes a hybrid control approach to improve the dynamic performance of three-phase PWM rectifiers under different operating conditions. Operating conditions are considered as step response, internal disturbance, and regenerative operation. First, Interval Type-2 Fuzzy Neural Network (IT2FNN) is designed and then antecedent and consequent parameters of IT2FNN are optimized with Modified Golden Sine Algorithm (GoldSA-II). The dynamic performance of the hybrid controller, named GoldSA-II-IT2FNN, is analyzed for all operating conditions in Matlab/Simulink environment. The simulation studies are realized to evaluate the performance of the proposed controller. In the simulations, settling times of proposed controller are observed as 27.2 ms, and 10.8 ms for step response, respectively. Moreover, recovery times are calculated as being 12 ms to 5.5 ms for internal disturbance, and 7.2 ms to 19 ms for regenerative operation, respectively. The obtained results demonstrate that the proposed controller not only provides better dynamic performance but also improves the stability of PWM rectifier.

A Quasi-Resonant Extended State Observer-Based Predictive Current Control Strategy for Three-Phase PWM Rectifier

In this letter, a quasi-resonant extended state observer-based predictive current control (QRESO-based PCC) strategy is proposed for three-phase pulse width modulation (PWM) rectifier. Specifically, the QRESO is utilized to estimate the predictive value of system total disturbance and grid current at time instant <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> +1 in the stationary <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">αβ</i> frame, and the required control input at time instant <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> +1 is then calculated based on the principle of deadbeat predictive control. The proposed control scheme can achieve robust control against to the electrical parameter variation, accommodate the measurement noise, and also assure the satisfactory steady-state and dynamic performance for the PWM rectifier. Besides, the stability analysis of QRESO and the whole current close-loop control system with the consideration of QRESO in the discrete-time domain are presented. Finally, several hardware-in-the-loop test results of the proposed control strategy are provided and compared with the model free predictive current control based on linear extended state observer and the generalized integrator-extended state observer-based PCC strategy, which validate the effectiveness and superiority of proposed QRESO-based PCC strategy.

Power Quality Analysis of a Hybrid Microgrid-Based SVM Inverter-Fed Induction Motor Drive with Modulation Index Diversification

The effects of varying modulation indices on the current and voltage harmonics of an induction motor (IM) powered by a three-phase space vector pulse-width modulation (SVM) inverter are presented in this research. The effects were examined using simulation and an experimental setup. IMs can be governed by an SVM inverter drive or a phase-angle control drive for applications that require varying speeds. The analysis of THD content in this study used the modulation index (MI), whose modification affects the harmonic content, and voltage-oriented control (VOC) with SVM in three-phase pulse-width modulation (PWM) inverters with fixed switching frequencies. The control technique relies on two cascaded feedback loops, one controlling the grid current and the other regulating the dc-link voltage to maintain the required level of dc-bus voltage. The control strategy was developed to transform between stationary (α–β) and synchronously rotating (d–q) coordinate systems. To test the viability of the suggested control technique, a 1-hp/3-phase/415-V experimental prototype system built on the DSPACE DS1104 platform was created, and the outcomes were evaluated with sinusoidal pulse-width modulation (SPWM).

A High-Performance Pll Observer for Sensorless Three-Phase Induction Motor Control

This paper presents an enhanced estimation algorithm based on the PLL (phase-locked loop) approach, which is used to estimate the rotor speed in induction motors (IM) drives. It can be challenging to obtain an accurate estimate during frequency ramps using existing PLL schemes. Thus, the performance of PLL schemes can be degraded during the acceleration and deceleration operations when applied to motor drives. In addition, the performance of conventional PLL scheme estimation is negatively affected by disturbances, for example, DC offsets. One of the novelties of the proposed speed observer (HPPO - High-Performance PLL Observer) is error normalization, which is based on the currents and a mechanism of variable gain based on the reference speed. The reference speed is also used to build an additional feedforward adjustment action. These modifications improve estimator results during load insertions and at low rates. In order to validate the proposed HPPO algorithm, it is implemented experimentally in a laboratory prototype using a 2.2kW IM. The motor is driven by a three-phase pulse width modulation (PWM) power converter, which is controlled by a DSP TMS320F28069. Numerical analysis and experimental results are carried out to validate the proposed scheme's high performance.

Generalized Clarke Transformation and Enhanced Dual-Loop Control Scheme for Three-Phase PWM Converters Under the Unbalanced Utility Grid

Three-phase grids imbalance causes serious alternating input current distortion in three-phase pulsewidth modulation (PWM) rectifiers where the conventional control scheme is employed. In this article, a generalized Clarke transformation is proposed to convert three-phase unbalanced sinusoidal quantities to two orthogonal sinusoidal quantities with equal amplitudes. Then, these two orthogonal sinusoidal quantities could be converted to two direct quantities by the Park transformation. Furthermore, based on the generalized Clarke transformation, an enhanced dual-loop control (EDLC) scheme is proposed to control the three-phase PWM rectifier in the synchronous rotating frame. Finally, a 5-kW Vienna-type rectifier prototype was built to verify the proposed generalized Clarke transformation and the proposed EDLC control scheme. Experimental results show that, by using the proposed EDLC scheme, the low current total harmonic distortion is achieved even both the amplitude and phase of the utility grid voltages are unbalanced.

A Cascaded Half-Bridge Three-Level Inverter With an Inductive DC-Link for Flexible Voltage Boosting

Voltage boosting three-level inverters may present a monotonically increasing or decreasing voltage gain when enlarging the pulsewidth modulation (PWM) ratio. To produce a flexible voltage gain, this article proposes a novel three-phase three-level PWM inverter by cascading a traditional two-level three-leg (B6) inverter with half-bridges. The proposed inverter is supplied by an inductive dc-link consisting of a dc source in series with an inductor that is charged by shooting through the half-bridges in the B6 structure. The voltages across the cascaded half-bridges are subsequently boosted, and the output voltage is stepped up due to the cascaded connection. A moderate voltage gain is achieved with proper selections of two modulation variables while maximizing the PWM ratio. In particular, when the two modulation variables are equal, a constant voltage boosting gain of two is maintained irrespective of the PWM ratio. Additionally, low voltages are induced on the components, which facilitates the use of low-voltage devices. The operating principle of the proposed inverter with a modified third-harmonic-injection PWM scheme is presented, followed with theoretical analysis, comparison, and design considerations. Experimental tests on a 1.5-kVA inverter prototype verify its feasibility.

A New Approach to Input Filter Design for Regenerative Cascaded H-Bridge Drives

The diode-front-end (DFE) cascaded H-bridge (CHB) inverter has prevailed in the nonregenerative industry drive domain for high power medium voltage applications due to its modularity, scalability, and fault-tolerant capability. The regenerative version of the CHB drives is made possible by adding the extra active-front-end (AFE) rectifier in each power cell, such as a three-phase Pulse width modulation (PWM) rectifier. However, AFE introduces the switching harmonics which requires to be attenuated by designing a grid interfaced filter to comply with the harmonic standard IEEE 519-2014. High-order filters like <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> filters are not preferred due to complex inherent resonances in a multiparallel AFE system. A large number of capacitive components in the system rouse multiple resonances, which decreases system reliability and modularity. This article proposes an active filtering strategy based on the optimal asymmetric carrier-shifting method for regenerative CHB drives with only <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> filters. The required filter size is reduced significantly while complying with IEEE 519-2014 standard and thus improves the overall size, cost, and efficiency. The proposed filtering strategy is validated experimentally using a seven-level regenerative CHB drive.

A Novel Zero-Sequence-Voltage-Balanced SVPWM With the Analyses of Common-Mode Voltage and Differential-Mode Current

In three-phase voltage source converters (VSCs), the high-frequency leakage current can be easily suppressed by the common-mode choke, while low-frequency component would be an unfavorable factor to the inductor design. Thus, as the excitation source, the low-frequency common-mode voltage (CMV) should be properly managed. This article analyzes the low-frequency CMV impulse by constructing a 3-D voltage vector space, and a novel modulation method is proposed to eliminate the low-frequency CMV. Meanwhile, a comparative study is conducted between the proposed method and the other four typical space vector pulsewidth modulation (PWM) (SVPWM) method from the view of CMV and differential-mode current (DMC). In the analysis, a double-current-ripple-envelopes method is proposed to describe the current ripples. Besides, the influence of modulation indexes and power factors on DMC are considered and evaluated. And a guiding rule for choosing the appropriate modulation method for three-phase VSCs is provided. Finally, the theoretical analysis and proposed method are experimentally validated under a 5-kW three-phase PWM converter.

General High-Order Selective Harmonic Repetitive Control for PWM Converters

In this article, a general high-order selective harmonic repetitive control (HO-SHRC) scheme is proposed, which is composed of a standard high-order repetitive controller structure and a new order-expandable SHRC. Different from conventional SHRC, the proposed new SHRC is capable of being applied into the standard high-order repetitive control (HORC) structure for generating any high-order SHRC. The proposed HO-SHRC can be used to improve the steady-state tracking accuracy of the pulsewidth modulation (PWM) converter systems and is robust to system frequency variations without changing the controller parameters online. The order expansion of the controller will lead to the increase of the implementation complexity, but it will bring the overall improvement of the controller performance, such as the improvement of frequency adaptability, steady-state tracking accuracy, and dynamic performance. Therefore, HO-SHRC can achieve a good compromise between the controller performance and the implementation complexity. Moreover, the proposed HO-SHRC provides a general structure for various repetitive controls (RCs), such as conventional RC (CRC), odd-harmonic RC (OHRC), high-order CRC (HO-CRC), and HO-odd-harmonic RC (HO-OHRC). Application examples of second-order (SO)- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6k~\pm $ </tex-math></inline-formula> 1 RC-controlled three-phase PWM inverter show the effectiveness and advantages of the proposed control scheme.

Performance of Neutral Point Clamped Five Level Inverter Using Space Vector Modulation Control Fed by DPC-VF-SVM Rectifier

The purpose of this paper is to develop a control and regulation method for the input DC voltage of a five level neutral point clamping (NPC) inverter feeding a induction motor. In this context, the authors propose in the first part, the control strategy of three-phase pulse width modulation rectifier, they propose the virtual flux-based direct control (DPC_VF) with vector modulation (SVM), this method is applied for the enhancement of network power quality by compensation of harmonic currents produced by an non linear load, and good regulation of DC-bus voltage. The second part of the paper is dedicated to the presentation of the model of the three phase, five-level NPC voltage source inverter with its space vector modulation (SVM) control method. The performance of the proposed strategy in terms of out-put voltage and THD has studied successfully and shown using MATLAB/Simulink.

A Novel Three-Vector-Based Model Predictive Direct Power Control for Three-Phase PWM Rectifier

A novel strategy of three-vector-based model predictive direct power control (MPDPC) is proposed for three-phase Pulse-width Modulation (PWM) rectifier. Under ideal grid conditions, three-vector MPDPC is studied, and a good control effect has been achieved. However, under the unbalanced power grid condition, the traditional control strategy has some problems, such as a high harmonic content of current and large instantaneous power pulsation. A new three-vector model predictive control is proposed based on the new instantaneous power theory, and the objective function is established by instantaneous power error. The duty cycle of the selected vector is calculated by solving the optimal objective function. Under an unbalanced power grid, this paper takes a three-phase PWM rectifier as a research object, and carries out simulation and experimental tests on the traditional and new control strategies. The experimental results show that the new control strategy has lower current harmonics, and eliminates the twice grid-frequency oscillation of the grid in instantaneous power.

Implementation on the dSPACE 1104 of VOC-SVM based anti-windup PI Controller of a three-phase PWM rectifier

&lt;p&gt;&lt;span&gt;The study made in this paper concerns the use of the voltage-oriented control (VOC) of three-phase pulse width modulation (PWM) rectifier with constant switching frequency. This control method, called voltage-oriented controlwith space vector modulation (VOC-SVM). The proposed control scheme has been founded on the transformation between stationary (α-β) and and synchronously rotating (d-q) coordinate system, it is based on two cascaded control loops so that a fast inner loop controls the grid current and an external loop DC-link voltage, while the DC-bus voltage is maintained at the desired level and ansured the unity power factor operation. So, the stable state performance and robustness against the load’s disturbance of PWM rectifiers are boths improved. The proposed scheme has been implemented and simulated in MATLAB/Simulink environment. The control system of the VOC-SVM strategy has been built based on dSPACE system with DS1104 controller board. The results obtained show the validity of the model and its control method. Compared with the conventional SPWM method, the VOC-SVM ensures high performance and fast transient response.&lt;/span&gt;&lt;/p&gt;

Comprehensive Modeling and Control of Grid-Connected Hybrid Energy Sources Using MPPT Controller

Nuclear and renewables energies are the two variants for low-carbon energy and the evolving grid suggests possible synergies between them. Nuclear energy introduces supple operations based on power demand, while renewables such as PV and wind hybrid systems depend on the presence and strength of sunlight or wind. For grid stability, there is need to improve their performance in order to overcome the impact of this disadvantage. The paper is a step in this direction as it addresses a detailed comprehensive dynamic modeling and an efficient control of grid-connected energy sources such as PV or wind system to increase system reliability and to ensure the power quality and safe operation of critical demands. The behavior of the suggested hybrid system is tested at different climate circumstances such as variation of sun radiation and wind speed. The PV is equipped with a boost converter and a three-phase pulse width modulation (PWM) inverter. The wind energy comprises a doubly fed generator (DFIG) based on a variable-speed wind turbine. The two controllers’ rotor-side and grid-side converters of DFIG have the ability to generate and observe reactive power, to keep constant speed of the rotor and control the DC-link voltage. The proposed scheme was investigated using MATLAB software. The maximum power point tracking (MPPT) was used for two systems, PV and wind, in varying weather conditions. The simulation results prove that the voltage at the point of common coupling was constant. Furthermore, the injected current of the grid side was in sinusoidal form and was synchronized with grid side voltage. In addition, the injected power-to-utility grid was around power delivered by the hybrid PV and wind system.