Three-phase Rectifier Research Articles

Robust direct power control of a three-phase PWM rectifier

This paper presents two robust controls techniques: current control in the dq reference frame and direct power control (DPC) applied to a three-phase PWM rectifier to achieve efficient dc voltage regulation, unit power factor control and harmonic distortion rate reduction. Simulations were performed using Matlab/Simulink software. According to these results, the DPC direct power control seems to be more efficient than the current control in the dq reference frame, which has a lower harmonic distortion rate, and the DC voltage follows its new reference for the two developed controls. However, the response time, overshoot and oscillations of the controlled quantities, as well as the exponential convergence of the errors for the transient regime and the setpoint change, are different. It can be seen that the best values of the latter are those obtained by applying the DPC direct power control, which is considered to be the best performing and most efficient control compared to the other control.

Dynamic stability analysis of the aircraft electrical power system in the more electric aircraft concept

This paper presents the modelling and analysis process of the electrical power management system on board an electrified aircraft conforming to the More/All Electric Aircraft concept. The main objective of the study is to assess the stability of the Electric Power Distribution System under different operational conditions, including the aspect of constant power loads. The paper describes the structure of the system, in which the key role is played by a synchronous generator and a three-phase rectifier converting alternating current AC into direct current DC. To solve the problem, modeling methods in the Matlab/Simulink environment were used, which enabled the analysis of the dynamic properties of the system and the assessment of stability under various types of loads. The obtained test results show that the presence of constant power loads can lead to instability in the EPDS system, manifested by voltage and current oscillations exceeding the standards specified in the MIL-STD-704E standard. The paper also provides tools for predicting system stability without the need to conduct full stability tests, which is important for the design of modern aviation power systems. The final section of the work presents the research results obtained and the resulting significant insights and practical conclusions.

Research on fault diagnosis for three-phase rectifier device in direct current transmission system based on continuous wavelet transform and vision transformer

Abstract As a core component of photovoltaic power generation systems, the three-phase rectifier device plays a crucial role, and its failure can potentially reduce energy conversion efficiency and output quality. Presently, the performance of fault time-domain signal diagnosis methods based on three-phase rectifier circuits is challenging to enhance. This paper proposes a novel fault detection method for three-phase rectifier devices based on Vision Transformer, referred to as CWT-ViT, to address this issue. This method transforms time-domain fault signals into images through Continuous Wavelet Transform (CWT), subsequently inputting these images into a Vision Transformer model. Relying on its powerful self-attention mechanism and fully connected layers, it realizes the extraction and learning of rectifier device image features. A Simulink simulation model of a three-phase bridge controllable rectifier circuit is established for fault injection to collect fault signals. Fault diagnosis experiments demonstrate that the proposed diagnostic method achieves a prediction accuracy of 98.6%, maintaining a relatively high precision level. In comparison to four excellent classification models currently available: AlexNet, RepVGG, ResNet, and GoogLeNet, the proposed method demonstrates superior diagnostic performance. Additionally, this paper conducts ablation experiments to meticulously analyze the impact of each module in the fault diagnosis process. This research achieves more precise and efficient fault diagnosis in photovoltaic power generation systems, thereby reducing downtime and maintenance costs for actual equipment and enhancing the stability of photovoltaic power generation systems. This research provides an innovative, intelligent solution for the intelligent operations and maintenance of photovoltaic power generation.

A Novel Shunt Zigzag Double-Tap Low-Harmonic Multi-Pulse Rectifier Based on a Three-Stage Power Electronic Phase-Shifting Transformer.

To solve the problem of the large size of traditional industrial frequency phase-shift transformers and the harmonic distortion of multi-pulse wave rectifier systems, this paper proposes a three-stage shunt zigzag power electronic phase-shift transformer based on a double-tap multi-pulse wave rectifier, which combines the power factor correction (PFC) converter with the voltage-type SPWM inverter circuit to form a power electronic converter to realize the frequency boost and power factor correction. Through AC-DC-AC conversion, the frequency of the three-phase AC input voltage is increased, the number of core and coil turns in the transformer is reduced to reduce the size of the phase-shifter transformer, a zigzag structure of the phase-shifter transformer is used to solve the unbalanced distribution of current between the diode bridges, and a passive harmonic suppression method on the DC side is used to generate a loop current by using a group of single-phase rectifier bridges to regulate the input line current of the phase-shifter transformer. The phase-shifted voltage is input into two three-phase diode rectifier bridges to rectify and supply power to the load. Simulation and semi-physical test results show that the proposed method reduces the total harmonic distortion (THD) value of the input current of the phase-shifted transformer to 7.17%, and the THD value of the grid-side input current is further reduced to 2.49%, which meets the harmonic standard and realizes the purpose of power factor correction as well as being more suitable for high-power applications.

Analysis of harmonic characteristics of the three-phase rectifier and the impacts on the power quality

Analysis of harmonic characteristics of the three-phase rectifier and the impacts on the power quality

Teaching three-phase half-wave power electronic rectifier with gamified augmented reality support

This paper presents a support tool designed for instructors in technical education within engineering programs, focusing specifically on power electronics and laboratory procedures related to the three-phase half-wave rectifier. The Augmented Reality (AR) application was developed for Android devices using Unity+Vuforia, employing a gamification-based approach. The application allows students to evaluate their knowledge and skills in real-time and offers an interactive learning environment. It provides learning diagnostics and sends each student's evaluation to a database stored on Google-Forms that is accessible by the instructor or assessor in question. It's important to note that this APP is freely accessible through the Android APP store. The learning strategy is around a game that tests players on their knowledge of measuring devices and theoretical concepts. Additionally, there is a puzzle task that encourages learners to correctly arrange the waveforms in a rectifier. Students can also connect the half-wave rectifier's essential connections and the transformer's delta-star connections through touch interaction. A comparison study between traditional teaching methods and the innovative AR-based approach has been conducted. This educational proposal itself is an innovative solution that will be especially helpful for laboratories lacking useful equipment in Mexican colleges. To test the effect of AR application on student success, an experimental study was conducted on two groups of students (a control group [non-using AR] and a test group [using AR]). To determine significant difference in acquired learning, an ANOVA statistical analysis was conducted using independent sample tests. According to tests result, there is a significant difference in the acquired knowledge for those who used the designed tool. The probability value (p = 1e-5 <0.05) for the use of AR is found. They increase their initial average grade from 27.08% to 72.3%, in contrast to the control group with no significant increasing learning, reporting an initial average grade of 28.75–43.33%. These results show that the use of AR in electronic practice makes a significant difference in student success.

Unidirectional Hybrid Three-Phase Rectifier with Boost Converter and Coupled Inductor

The unidirectional hybrid three-phase rectifier (UHTR) with Boost converter consists of two different rectifiers (Rectifier 1 and 2), where Rectifier 2 consists of modules corresponding to the phases. Each rectifier processes different part of the current waveform at the input, so that the sum of the current waveform parts is sinusoidal, or multilevel. Analyzing existing literature, the UHTR with Boost converter and isolation transformer, is proven as a classic solution with high weight, volume and cost. Therefore, in 2019 the UHTR with Boost converter was proposed, without any isolation transformer. To do this, it was necessary to replace the Boost inductor of each Rectifier 2 module with a coupled inductor. However, the proposed UHTR has not described the coupled inductor in details, neither the control circuit and the decoupling of the power circuit with the control circuit were described. Therefore, this main objective this paper is to provide answers to those aspects, and consequently present the UHTR proposal in a more realistic and practical application way, thus favoring the implementation of the prototype. A simulation of the proposed UHTR with coupled inductor was performed in the PSIM version 12.0 software with a power of 20 kW. The results of the proposed UHTR show that there is no current interaction and it works correctly, having a high PF of 99.92% and low total harmonic distortion of 3.96% at full load. In this way, it is proven that it is possible to implement an UHTR with a Boost converter and using coupled inductor.

Discrete-Time Adaptive Control for Three-Phase PWM Rectifier.

This paper proposes a dual-loop discrete-time adaptive control (DDAC) method for three-phase PWM rectifiers, which considers inductance-parameter-mismatched and DC load disturbances. A discrete-time model of the three-phase PWM rectifier is established using the forward Euler discretization method, and a dual-loop discrete-time feedback linearization control (DDFLC) is given. Based on the DDFLC, the DDAC is designed. Firstly, an adaptive inductance disturbance observer (AIDO) based on the gradient descent method is proposed in the current control loop. The AIDO is used to estimate lump disturbances caused by mismatched inductance parameters and then compensate for these disturbances in the current controller, ensuring its strong robustness to inductance parameters. Secondly, a load parameter adaptive law (LPAL) based on the discrete-time Lyapunov theory is proposed for the voltage control loop. The LPAL estimates the DC load parameter in real time and subsequently adjusts it in the voltage controller, achieving DC load adaptability. Finally, simulation and experimental results show that the DDAC exhibits better steady and dynamic performances, less current harmonic content than the DDFLC and the dual-loop discrete-time PI control (DDPIC), and a stronger robustness to inductance parameters and DC load disturbances.

Back Propagation Artificial Neural Network Based DC Bus Capacitance Identification Method in Three-Phase PWM Rectifier for Charging System of EVs

In order to improve the performance and reliability of the three-phase PWM rectifier in electric vehicle (EV) charging system, it is important to focus on the identification of the DC bus capacitance. The existing methods have the disadvantages such as a low identification accuracy, a high hardware dependency, and high costs. Therefore, the development of new identification methodologies could be the way out of the aforementioned disadvantages, in terms of advanced algorithms. In this paper, a DC bus capacitance identification method based on back propagation (BP) artificial neural network (ANN) algorithm is proposed. The capacitance can be accurately identified in the diode rectification stage, by training the neural network to extract the potential laws in the data, which only includes the Phase-a voltage and current, as well as the DC bus voltage ripple. The regression response is 0.99991. Finally, the experimental results show the accuracy and effectiveness of the proposed method. A simple and effective BP ANN is designed, and it can identify the capacitance at different grid voltages and DC bus loads. It has a high identification accuracy that the maximum identification error is less than 4.5%.

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.

ЕНЕРГЕТИЧНІ ПОКАЗНИКИ ПЕРЕТВОРЮВАЧА ЕНЕРГІЇ МОРСЬКИХ ХВИЛЬ З ВИПРЯМЛЯЧЕМ СТРУМУ ТА АКТИВНО-ЄМНІСНИМ НАВАНТАЖЕННЯМ

The article is dedicated to determining the energy indicators of a generating complex with stochastic wave energy gen-eration. The aim of the study is to compare the energy indicators and power consumption coefficient of wave energy generating complexes' simulation models with magneto-electric generators operating at variable speeds under resistive and resistive-capacitive loads with rectified voltage. The analytical method is employed to calculate the parameters and energy indicators of the magneto-electric generator. The calculation includes inductance, resistance, and voltage gen-erated by the rotor with permanent magnets in the three-phase winding of the magneto-electric generator for electrical circuit modeling with and without a three-phase current rectifier, as well as active-reactive and active loading. The rotor rotation frequency varies harmonically with the same period and amplitude for all electrical circuits. The deter-mined current in the electrical circuits is used to calculate the generator's electromagnetic field and energy indicators. Comparisons are made for circuits with active and active-reactive loads, including power consumption, power losses in the stator winding, power output from the generator, and the power consumption coefficient of wave energy. The com-parison of energy indicators is conducted under the condition of equal rotor oscillation frequency and shaft torque, achieved by varying the load resistance. Bibl. 10, fig. 8, table.

Robust Direct Power Control of Three-Phase PWM Rectifier with Mismatched Disturbances

To effectively eliminate the impacts of both matched and mismatched power disturbances in a three-phase PWM rectifier, this paper proposes a robust direct power control (RDPC) method with a single-loop control structure. Firstly, a nonlinear power model of the three-phase PWM rectifier is established. Then, using the exact feedback linearization method, a linearized power model including matched and mismatched power disturbances is derived and achieves the decoupling of active and reactive power. Secondly, to regulate the DC bus voltage, a sliding-mode controller (SMC) combined with a nonlinear disturbance observer (NDO) is proposed. The proposed SMC combined with an NDO (SMC + NDO) method features a single-loop control structure, which enables a faster response and simpler structure compared to the dual-loop DPC method. By incorporating estimated mismatched power disturbance into the sliding-mode surface, it overcomes the SMC’s defect in incompletely suppressing mismatched disturbances and enables the simultaneous regulation of voltage and active power. Additionally, it effectively reduces sliding-mode chattering. To regulate reactive power, a sliding-mode controller based on the exponential convergence law is designed to suppress matched reactive power disturbances. Finally, the simulation and experimental comparative results demonstrate that the proposed controller exhibits stronger robustness against matched and mismatched power disturbances, as well as a better performance under the constant power load (CPL).

Nonisolated Three-Phase Current DC-Link Buck–Boost EV Charger With Virtual Output Midpoint Grounding and Ground Current Control

Non-isolated three-phase AC/DC converter concepts facilitate more compact and more efficient realizations of future EV chargers. However, without the galvanic isolation and/or high common-mode (CM) impedance provided by an isolation transformer, non-isolated chargers must employ other means to suppress CM leakage currents to ground sufficiently and to prevent nuisance tripping of mandatory residual current devices (RCDs). Typically, the required EMI filters reduce high-frequency (HF) CM leakage currents to uncritical values. However, low-frequency CM voltages, e.g., generated by third-harmonic injection, may drive significant LF CM currents through the parasitic capacitances of the DC output (including the battery pack) to protective earth (PE). Therefore, considering a non-isolated three-phase buck-boost current DC-link PFC rectifier system that consists of a buck-type current-source rectifier (CSR) stage and a three-level boost-type DC/DC-stage, this paper first proposes a virtual grounding control (VGC) of the DC output voltage midpoint. VGC employs the DC/DC-stage to compensate the LF (third-harmonic) CM voltage inherently generated by the CSR-stage, and thus controls the LF CM voltage between the DC output midpoint and PE to zero. This enables further a direct connection of the DC output midpoint to PE, where an additionally proposed ground current control (GCC) ensures near-zero LF CM leakage current. The proposed concepts are verified with a 10kW hardware demonstrator (power density of 6.4 kW/dm3 or 107.5 W/in3, full-load peak efficiency of 98.5%) considering TT (Terra-Terra) and TN (Terra-Neutral) grounding systems. With a direct connection of the DC output midpoint to PE, GCC limits the LF CM leakage current to < 6mA RMS, i.e., significantly below typical RCD trip levels, and, using the human-body impedance model according to UL 2202, achieves a test voltage of 110mV that is clearly below the most stringent limit (250 mV) of the standard.

Three-Phase Current Source Rectifier With Reduced Voltage Stress on Switching Devices and Common Mode Current Mitigation

Three-Phase Current Source Rectifier With Reduced Voltage Stress on Switching Devices and Common Mode Current Mitigation

Structure Optimization of Ultra-Light Power Generation System

A wide-speed, ultra-light power generation system is a critical power generation unit structure, often because of its high efficiency and power density. Lightness and reliability are two key design indicators within the system, albeit they could lead to contradictory problems, particularly in systems containing prime movers, batteries, generators, rectifiers, and inverters. Ultra-light generator sets are facing more severe problems and contradictions in designing in terms of matching, coordinating, and stabilizing the components in the systems. This paper describes the system design of a low-cost and high-reliability microgenerator set: a gasoline engine, three-phase permanent magnet synchronous generator, rectifier, and inverter. Moreover, the matching relationship between the four parts and the design effect of each part of the power generation system was analyzed, simulated, and tested to verify the effectiveness and feasibility of the so-designed system.

Improved study on double closed-loop control of three-phase PWM rectifier based on induction heating rectifier side

With the development of power electronics technology, induction heating power supply becomes more applicable. The three-phase PWM rectifier is widely used in induction heating system because of its advantages of better power factor and bi-directional energy transfer, and often adopts the control method of voltage outer loop and current inner loop to improve its control performance. However, the traditional rectifier control structure in the application process will appear such as poor anti-interference ability, low fault tolerance and other outstanding problems. In this paper, an improved H∞ controller is designed for the induction heating system based on the rectifier-side power regulation by combining the robust control principle, establishing a state space model of the system with an equivalent series resonant load, firstly decoupling the linearization of the model, and then designing a double-closed-loop PI controller as well as an improved current inner-loop H∞ controller based on the decoupled model. In order to facilitate the analysis, the PI controller and the H∞ controller are simulated under two kinds of starting conditions, and the comparison further confirms that the improved system has better anti-interference ability and dynamic characteristics.

Alternative Performance Indices-Based Control Technique for a Unity Power Factor Three-Phase Rectifier

The implementation of a unity power factor (UPF) three-phase rectifier has the potential to enhance the power factor (PF). However, the PF and total harmonic distortion (THD) experience degradation in low-output regions due to the utilization of a “critical input inductor” under rated load conditions. In this study, an analysis of the operation principle of a UPF three-phase rectifier is conducted and a reference compensation current technique based on alternative performance indices is proposed. The optimal control algorithm is utilized to calculate the single harmonic phase delay of each phase and determine the compensator gain, taking into account factors such as the single harmonic distortion limit, THD limit, PF, and active power consumption. The output of the current compensator serves as the desired current source, which in turn drives the bidirectional switches. The simulation and experimental results demonstrate that the proposed control technique can significantly mitigate power supply current distortion, and the input power factor has been effectively improved within a wider load range.

A Low-Cost Wind Generator System with a Permanent Magnet Synchronous Generator and Diode Rectifiers

A low-cost wind generator systemfor small- or medium-scale wind generator is pro-posed. The system consists of a permanent mag-net synchronous generator (PMSG) with two sets ofthe three-phase stator windings, i.e. six-phase sta-tor winding, two three-phase diode rectifiers, a boostchopper, and a three-phase pulse-width modulation(PWM) inverter. Since two sets of three-phase statorwindings are spatially shifted by 30 electrical degrees,the system can cancel out the dominant harmonicmagnetomotive forces (MMF) produced by the har-monic currents of diode rectifiers. The simulation andexperimental results show that the proposed systemcan significantly reduce the pulsation of the devel-oped torque and the DC current by more than 60 %in comparison with the conventional system consist-ing of a three-phase PMSG and a three-phase dioderectifier. Therefore, the proposed system can use asmaller smoothing reactor in the boost chopper, sothat the lower initial cost can be realized, and it issuitable for small- or medium-scale wind generatorsystems.

Novel soft-start method for three-phase voltage source rectifier based on virtual resistor control

Novel soft-start method for three-phase voltage source rectifier based on virtual resistor control

FEA simulation of harmonics generation from 6-pulse rectifier and their impact over rectifier’s transformer

In the present work, the operation of a 6-pulse three-phase rectifier supplying a powerful DC consumer is simulated using the finite element method (FEM). The purpose of the simulations is to research the generation of harmonics from the rectifier circuit and to investigate their influence on the transformer supplying the three-phase bridge rectifier. For this purpose, two co-simulations were made. The first of them is realized with the help of the professional Finite Element Analysis (FEA) software - Ansys Electromagnetic Suite. The voltage-driven model of the rectifier transformer for FEA was built and was used in the Ansys Twin Builder software simulation. The resulting current harmonics from the FFT analysis of the current waves with their amplitudes and phases are input into the primary and secondary windings of the transformer current-driven model in the second electromagnetic-thermal co-simulation in Ansys Workbench to calculate the losses in the transformer. These losses are used in the thermal model to account for transformer heating from higher harmonics.