Single-phase Pulse Width Modulation Research Articles

Rectifier Fault Diagnosis Based on Euclidean Norm Fusion Multi-Frequency Bands and Multi-Scale Permutation Entropy

With the emphasis on energy conversion and energy-saving technologies, the single-phase pulse width modulation (PWM) rectifier method is widely used in urban rail transit because of its advantages of bidirectional electric energy conversion and higher power factor. However, due to the complex control and harsh environment, it can easily fail. Faults can cause current and voltage distortion, harmonic increases and other problems, which can threaten the safety of the power system and the train. In order to ensure the stable operation of the rectifier, incidences of faults should be reduced. A fault diagnosis technique based on Euclidean norm fusion multi-frequency bands and multi-scale permutation entropy is proposed. Firstly, by the optimal wavelet function, information on the optimal multi-frequency bands of the fault signal is selected after wavelet packet decomposition. Secondly, the multi-scale permutation entropy of each frequency band is calculated, and multiple fault feature vectors are obtained for each frequency band. To reduce the classifier’s computational cost, the Euclidean norm is used to fuse the multi-scale permutation entropy into an entropy value, so that each frequency band uses an entropy value to characterize the fault information features. Finally, the optimal multi-frequency bands and multi-scale permutation entropy after fusion are used as the fault feature vector. In the simulation system, it is shown that the method’s average accuracy is 78.46%, 97.07%, and 99.45% when the SNR is 5 dB, 10 dB, and 15 dB, respectively. And the fusion of multi-scale permutation entropy can improve the accuracy, recall rate, precision, and F1 score and reduce the False Alarm Rate (FAR) and the Missing Alarm Rate (MAR). The results show that the fault diagnosis method has high diagnosis accuracy, is a simple feature fusion method, and has good robustness to working conditions and noise.

A Voltage Source Inverter-Based Hybrid Renewable Energy Source for Improving Power Quality

The power demand is quickly rising day by day and however, the available industrial sector needs the demand for power high. Therefore, different loads and different output sources can be employed between supply and demand. This approach intends to assess the current condition need for power quality, without distortion, and Bus interface management with fully integrated PV-based MPPT (Maximum power point tracking) and Wind-based rotor winding induction generator. Solar energy is directly converted into electrical energy using a Photovoltaic (PV) system. The PV cell is the fundamental component of a PV array and can be created by grouping cells and the voltage and current that are accessible at a PV device's contacts. In solar PV, the MPPT technique and boost converter are used to maximize the buck or boost and feed it to the single-phase Pulse Width Modulation (PWM) to the inverter. The rectifier circuit rectifies the AC input source and is connected through the controller; simultaneously, the DC-DC converter converts the DC input and bucks or boosts up the from the input sources. The voltage source inverter is combined with shunt active power filter functionality, which is further used to interface the DC-shunted wind-solar hybrid model to the grid. A voltage source inverter has more efficiency and both different input sources are connected via a DC bus. In this method, both DC and AC output loads are connected, managing the desired output voltage with efficient and better output results, and analyzing the total harmonics distortion method using Mat-lab simulation.

A Multiple-Sensor Fault-Tolerant Control of a Single-Phase Pulse-Width Modulated Rectifier Based on MRAS and GPI Observers

Due to their advantages in ensuring low harmonic distortion and high power factors, single-phase Pulse-Width Modulated (PWM) rectifiers are widely employed in several industrial applications. Generally, the conventional control loop of a single-phase PWM rectifier uses both voltage and current sensors. Hence, in case of sensor fault, the performance and the availability of the converter can be seriously compromised. Therefore, diagnosis approaches and fault-tolerant control (FTC) strategies are mandatory to monitor these systems. Accordingly, this paper introduces a novel multiple-sensor FTC scheme for a single-phase PWM rectifier. The proposed fault diagnosis approach relies on joining several Generalized Proportional Integral (GPI) and Model Reference Adaptive System (MRAS) observers with a residual generation technique to detect and isolate sensor faults in a simple and reliable manner. While conventional sensor FTC methods dedicated to PWM rectifiers can only deal with single faults, the suggested approach guarantees a very good effectiveness level of sensor fault detection, isolation (FDI) and FTC of multiple-sensor fault occurrence scenarios. Consequently, the single-phase PWM rectifier can work with only the survivable single sensor with the guarantee of very good performance as in healthy operation mode. The effectiveness of the proposed sensor FDI approach and its control reconfiguration performance are demonstrated through both extensive simulation and experimental results.

Fuel cell stack design and modelling with a double-stage boost converter coupled to a single-phase inverter

Abstract A comprehensive proton-exchange membrane fuel cell stack model was developed and integrated with a two-stage DC/DC boost converter. It was directly coupled to a single-phase (two levels—four pulses) inverter without a transformer. The pulse-width modulation signal was used to independently regulate every converter phase. The converter was modelled using a MATLAB®/Simulink® environment and an appropriate voltage control method. The analysis features of the suggested circuit were created and, through established experiments, the simulation results were verified. A single-phase (two levels—four pulses) inverter control circuit was tested and it produced a pure sinusoidal waveform with voltage control. It matches the voltage of the network in terms of amplitude and frequency. A sinusoidal pulse-width modulation approach was performed using a single-phase (two levels—four pulses) pulse-width modulation inverter. The results demonstrated an enhancement in the standard of the output wave and tuned the dead time with a reduction of 63 µs compared with 180 µs in conventional techniques.

A High-Accuracy-Light-AI Data-Driven Diagnosis Method for Open-Circuit Faults in Single-Phase PWM Rectifiers

Data-driven solutions like artificial intelligence (AI) are more upright and effectual for fault diagnosis in the power converter system. To decrease computing load and improve the diagnosis speed of the intelligent algorithm, a high-accuracy-light-AI data-driven open-circuit diagnosis method is proposed to diagnose single or multiple IGBT open-circuit faults in the single-phase pulse width modulation (PWM) rectifiers. Firstly, the fault characteristics of three fault scenarios are analyzed to seek the most critical features and provide prior knowledge for developing the intelligent diagnostic algorithm. Then, a fast-learning algorithm named random vector function link network (RVFL) is utilized to extract the mapping knowledge between the well-selected features and fault modes. To balance the testing accuracy and calculation time of the diagnostic algorithm, the RVFL parameters are tuned to decrease the computing burden. After that, a decision-making framework is designed for identifying the faults in real-time. Finally, the effectiveness of the proposed fault diagnosis method is thoroughly verified by extensive experimental tests. A substantial comparison to state-of-the-art techniques shows the proposed scheme’s superiority in diagnostic accuracy, computing time, and diagnosis time.

VWM-DCRNN: A Method of Combining Signal Processing With Deep Learning for Fault Diagnosis in Single-Phase PWM Rectifier

Based on variational mode decomposition and dual model of convolutional recurrent neural network (VMD-DCRNN), a novel diagnosis method is proposed to discover the faults of IGBTs, diodes and series resonant circuit in single-phase pulse width modulation (PWM) AC-DC rectifier, an important part of traction power supply system of high-speed railway. By virtue of the combination of signal processing and deep learning schemes, the multi-scale feature information for fault diagnosis is extracted by regarding the input current of the rectifier and the voltage of dc side as the original signal. More clearly, VMD is adopted to decompose the original signal to a series of intrinsic mode function components (IMFs). Then, the submodel of current is designed to detect the fault types of IGBTs and diodes. Meanwhile, the submodel of voltage is established to identify the fault types of series resonant circuit. These IMFs are fed into DCRNN consisting of the two submodels for training and testing. Finally, the features extracted from the two submodels are integrated and converted to label space to complete fault diagnosis. Experimental results show that the proposed VMD-DCRNN algorithm is superior to the single-channel models, reaching 96.27%.

Disturbance Decoupling for a Single-Phase Pulse Width Modulation Rectifier Based on an Extended H-Infinity Filter

The growing utilization of single-phase pulse width modulation (PWM) rectifiers in various applications has spurred interest in detecting and monitoring faults in these devices. In particular, voltage and current sensors play a crucial role in the control loop of these rectifiers. However, sensor faults can significantly affect the converter’s performance and availability. This paper introduces a novel and efficient method for detecting and decoupling sensor faults in single-phase PWM rectifiers. The proposed method utilizes residual generation and incorporates an extended filter within the rectifier. Unlike conventional filters, the presented fault detection and isolation (FDI) method effectively eliminates the influence of disturbances on the residual signal. This feature helps prevent false alarms in the monitored system, ensuring reliable fault detection. To evaluate the effectiveness of the approach, hardware-in-the-loop and simulation tests were conducted. The results from these tests provide substantial evidence supporting the efficacy of the proposed method. The hardware-in-the-loop experiments involved real-world implementation, validating the practicality and reliability of the approach. Meanwhile, simulation tests allowed for a comprehensive analysis of system behavior and performance under various fault scenarios. The findings demonstrate the rapid and dependable nature of the proposed method for detecting and decoupling sensor faults in single-phase PWM rectifiers. By effectively mitigating the impact of disturbances on the residual signal, false alarms are minimized, ensuring accurate fault detection. The experimental validation highlights the practical applicability and effectiveness of the proposed approach, making it a valuable contribution to fault detection in single-phase PWM rectifiers.

Robust Sensor Fault Detection for a Single-Phase Pulse Width Modulation Rectifier

Maintaining safe and efficient operation in a single-phase pulse width modulation (PWM) rectifier that employs current sensors relies heavily on accurate sensor readings. However, several factors such as environmental conditions, aging, or damage can lead to sensor faults. Therefore, it is imperative to implement robust fault detection methods to ensure reliable system operation. The use of unknown input observer techniques is one such method that involves analyzing the differences between actual and estimated states to detect and identify faults in the system. This paper presents the development of a fault detection method that employs an unknown input observer with high sensitivity to faults and disturbance rejection to achieve robust fault detection. The method involves modeling the system as a state-space model and designing an observer to estimate the system’s state variables based on input and output measurements. The deviations between the actual and estimated states are then analyzed to detect and identify sensor faults, without the need for additional hardware, making it a cost-effective solution. Hardware-in-the-loop tests confirm the effectiveness of the proposed method.

Single-phase energy-fed AC electronic load based on DQ current decoupling

The single-phase pulse width modulation (PWM) converter is the main research object to realize single-phase AC electronic load. To achieve high-quality energy feedback, this paper studies the topology of the PWM rectifier, the mathematical model of DQ current decoupling control, SOGI-PLL phase-locked model analysis, and the energy feedback unit with bipolar SPWM inversion to 50 Hz sinusoidal AC. The scheme is simulated and validated by Matlab/Simulink. The simulated characteristic unit can simulate resistive, inductance, and capacitive loads. The energy feedback unit can verify the stability, high efficiency, and practicability of the scheme with 50 Hz sinusoidal AC feedback.

Common-Ground-Structured High-Reliability Single-Phase AC–AC Converters

This paper proposes enhanced single-phase pulse width modulation buck, boost, and buck-boost-type ac-ac converters. The proposed converters, in which input and output voltages share a common ground, require no isolated voltage sensor and have no leakage current problem. The commutation problem is solved with series-connected switching cell structures without using a RC snubber. In addition, switching patterns are determined using only the polarity of input voltage, allowing the inductor currents to flow through switching devices during all operational modes. Because two switches are always turned on during a half-period of the input voltage, the switching loss is significantly reduced. Detailed analysis and experimental results are provided to verify the performance of the proposed converter.

A Simple Model Predictive Instantaneous Current Control for Single-Phase PWM Converters in Stationary Reference Frame

The traditional proportional–integral (PI) based current control for single-phase pulsewidth-modulation (PWM) converters in railway traction applications either has a steady-state error or a poor dynamic response. Deadbeat instantaneous current control (ICC) cannot eliminate the steady-state error due to approximation errors of the linear extrapolation. Compared with PI-based direct current control, continuous-control-set (CCS) model predictive control (MPC) implemented in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d-q</i> frame offers better performance, but its dynamic response is still slower than ICC. To solve these problems, a simple model predictive (MP) ICC scheme for single-phase PWM converters is proposed in this article. The optimal modulation function is calculated in the stationary reference frame by the CCS-MPC principle without <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> -axis current estimation and reference frame transformation. The proposed MP-ICC scheme can keep the fast dynamic response characteristics of ICC and achieve zero steady-state error. In addition, it has the advantages of low current harmonics and low computational complexity. The influence of the inductance parameter mismatch on the current loop is analyzed in detail, and a phasor-method-based inductance parameter online estimation is developed. This solution can be executed during the idle time of the digital processor without making the control delay longer. Finally, a comprehensive experimental comparison with four existing current control schemes is conducted to verify the feasibility and effectiveness of the proposed scheme.

Low-Frequency Oscillation Analysis in Train-Traction Power Supply System Using an SISO Voltage Loop Model

Low-frequency oscillation (LFO) in the train-grid coupling system severely endangers the stability and safety of railway operation. It is well known that this phenomenon is caused by impedance mismatch among the trains and the traction power supply system (TPSS). A novel voltage loop model of the single-phase pulsewidth modulation rectifier is proposed in this article. Unlike the commonly adopted multi-input multi-output (MIMO) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$d$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$q$ </tex-math></inline-formula> impedance model in the literature, this is a single-input single-output (SISO) model that enjoys some advantages, such as easier calculation of the system poles and quantitative analysis of the stability margin. The most attractive character of this model in comparison to the MIMO one is perhaps the decoupling of the controller and the voltage loop. This paves the way toward the analytical design of the dc-link voltage controller (DVC), whereas the impedance model is mainly useful for analysis. Furthermore, the maximum amount of trains allowed for keeping stability is derived from the steady-state equation. Robust stability margin (RSM) and sensitivity analysis are adopted to quantitatively investigate the influence of the control parameters and the circuit element parameters. LFO is guaranteed to be eliminated permanently by adjusting the controller parameters.

A New Technique for Online Open Switch Fault Detection and Location in Single-phase Pulse Width Modulation Rectifier

A New Technique for Online Open Switch Fault Detection and Location in Single-phase Pulse Width Modulation Rectifier

Control system design of a low‐frequency‐switchingsingle‐phase four‐quadrant PWMconverter

This work is focused on the control of low-frequency-switching single-phase four-quadrant pulse width modulation (PWM) converters used in grid-connected modern power electronics applications. The switching frequency is chosen to be lower than that used in industrial applications in order to use the designed control system in high-power applications such as railway electrical traction systems. The control system is designed under three main headings: grid synchronization, input current control, and voltage control, where grid synchronization is achieved by a single-phase phase-locked loop (PLL). The current loop is designed by using a proportional-resonant (PR) controller, and the classical proportional-integral (PI) controller is employed in the voltage control loop. The parameters of the PI controller are determined by using the coefficient diagram method (CDM). The control system is modelled as a discrete-time system to get the response closest to the actual system and to be easily implemented on the TMS320F28335 DSP platform. The performance of designed control system is tested on a 30-kW single-phase PWM converter test set-up, and experimental results show that bidirectional power flow, sinusoidal input current, power factor correction, and constant output voltage are achieved. This study is aimed to be a guide for the designers, from the selection of converter passive elements to controller design and experimental verification.

Robust current control scheme for single‐phase PWM rectifiers based on improved μ ‐synthesis in electric locomotive

The parameter perturbation of grid-side equivalent inductance is a significant feature of the uncertainty in the single-phase pulse-width modulation rectifiers system for the electric locomotive. This characteristic tends to reduce the robustness of the rectifier system. This study handles these problems in the framework of the structured singular value, which helps to reduce the influence of model parameter perturbation, caused by measurement error and operation condition change, on the robustness. However, the conventional μ-synthesis robust controls only reflect tracking and anti-disturbance performance by weighting functions and ignoring the dynamic response performance. Herein, a direct current control (DCC) scheme based on improved μ-synthesis is proposed. A desired closed-loop transfer function is introduced to the conventional μ-synthesis control structure to ameliorate the performance of the dynamic response. Furthermore, considering the external disturbances on the system control output, a suitable weighting function is used to restrict the external disturbance. The input–output relationship of the generalised open-loop plant can thus be constructed accordingly. The proposed control scheme is compared with the widely applied proportional–integral-based DCC scheme and the conventional μ-synthesis DCC scheme. Hardware-in-the-loop experiment results show promising dynamic performance as well as stronger robustness against parameter perturbation and external disturbances.

An Improved Bipolar-Type AC–AC Converter Topology Based on Nondifferential Dual-Buck PWM AC Choppers

A novel single-phase pulsewidth modulation (PWM) direct ac-ac converter based on two-level nondifferential dual-buck ac chopper legs with inverting and noninverting operations is first proposed in this article. It has the ability to resolve both voltage sag and swell problems at the same time when used as distributed flexible voltage conditioner. Compared to the traditional ac-ac converter, it has much enhanced system reliability thanks to no shoot-through problems even when all switches of each ac chopper legs are turned on, and therefore, the PWM dead time is not needed leading to improve the utilization of the duty cycles. Only half of the switches in the proposed converter is switched at high frequency during a switching period at most, which significantly reduces the total switching loss. In particularly, the converter has two greatest advantages that it retains the common sharing ground of the input and output and has the same buck/boost operation process for noninverting and inverting modes. In order to fully testify the performance of the proposed converter, a 500-W experimental prototype is built and tested at different conditions.

± 180° Discontinuous PWM for Single-Phase PWM Converter of High-Speed Railway Propulsion System

As high-capacity alternating current/direct current (ac/dc) power conversion systems, single-phase pulse-width modulation (PWM) converters used in high-speed railway propulsion systems adopt high-voltage Insulated-Gate Bipolar Transistors (IGBTs) as switching elements. Due to their high breakdown voltage characteristics, the switching dynamics are inferior to those of low-voltage IGBTs and switching losses are more dominant than conduction losses despite operating at relatively low switching frequencies of hundreds to several kHz. To solve this problem, this paper proposes ± 180° discontinuous PWM (DPWM) suitable for a single-phase circuit. With the simple addition of offset voltages, the proposed DPWM method can be implemented easily and switching losses can be reduced by half by clamping the switching legs of the H-bridge converter to the positive or negative dc rail during every half cycle. In addition, temperature deviation between the power stacks can be minimized by using selective application of clamping modes. The validity and effectiveness of the proposed DPWM are verified through simulations and experiments of a prototype converter.

Optimized Switching Finite Control Set Model Predictive Control of NPC Single-Phase Three-Level Rectifiers

A new model predictive control scheme, optimized switching finite control set model predictive control, is studied in this article for neutral-point-clamped (NPC) single-phase three-level pulsewidth modulation (PWM) rectifiers. To ensure the actual stability of the power converter, the ac-side current error of single-phase PWM rectifier and the neutral point voltage of the converter are both converged to the bounded invariant set, and the adjustment of system performance is thus realized by setting the bounded invariant set. Based on the NPC single-phase three-level PWM rectifier model, the ac-side current, the neutral point voltage, and the current error in the future time can be predicted in advance. The above objectives are achieved by optimizing the selection of switch combinations. The advantage of the proposed method is that it can reduce the average switching frequency of the converter when the ac-side current error and the neutral point voltage of the converter are controlled within a certain range, which makes it suitable for the application of high-power single-phase PWM rectifier.

A new pulsating power elimination method based on ANFIS and PR control structures applicable for single-phase PWM rectifiers

In the input power of single-phase Pulse Width Modulation (PWM) rectifiers there is a pulsating portion with twice the grid frequency. To prevent the transferring of pulsating power to the DC side, it should be filtered properly. A convenient method is to install a high-capacitance capacitor at the DC side which cannot be an appropriate solution due to its undesirable characteristics. This paper proposes an active method for eliminating the pulsating power in which the control system is based on Adaptive Network-based Fuzzy Inference System (ANFIS) architecture. To improve the controller performance, an online supervisory learning algorithm based on the Error Back Propagation (EBP) learning method is employed. This approach leads to a control system with minimal structure, enhanced accuracy and improved dynamics. Also, a Proportional Resonant (PR) controller is proposed and the results of two controllers are compared with each other and with one of the most outstanding previous works. Moreover, a superseded control method based on ANFIS architecture for the conventional control system of single-phase PWM rectifiers is suggested. The proposed methods’ efficiency are confirmed by extensive simulations in MATLAB/Simulink.

Coupled Inductor Based Regenerative Cascaded Multicell Converter for Drives With Multilevel Voltage Operation at Both Input and Output Sides

Cascaded multicell converter (CMC) is proved to be an effective solution for medium voltage drives. Three-phase diode bridge rectifiers are normally used in this converter, which do not have regeneration capability. Pulsewidth-modulated (PWM) rectifier-based power cells enable the drives with regeneration capability. However, due to their two-level voltage operation at the input side, an inductor is required for each cell to filter out the switching frequency components from the input current. In this paper, a new configuration with single-phase PWM rectifier-based power cell is proposed to achieve multilevel voltage operation at both the input and output sides of the converter. Therefore, the devices at the rectifier side are also operated at reduced switching frequency without using any filter inductor for each cell. In the proposed converter, simple modular transformers are used instead of a single large and complex transformer that is used in the conventional CMC. Further, input phase currents of the converter are controlled in the synchronously rotating d–q frame, which requires only two current sensors at the input side instead of individual current sensors for each cell. Experimental validation of the proposed converter configuration is carried out on a 4.5-kVA prototype, and the results are presented.