Rectifier System Research Articles

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 Moreover, a superseded control method based on ANFIS architecture for the conventional control system of single-phase PWM rectifiers is suggested.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.

Active Phase Fault-Tolerant Control of 12-Phase Permanent Magnet Synchronous Generator Controllable Rectifier System

The multi-phase permanent magnet synchronous generator controllable rectification system has the capability of fault-tolerant operation and high reliability, and is widely used in ship power systems. After a phase loss fault occurs in such a system, the DC current output from each rectifier bridge is unbalanced, and the DC voltage ripple coefficient increases. In this paper, from the perspective of power balance distribution of residual phase windings and the symmetrical operation of the system, the design of fault-tolerant control strategy is carried out with current equalization and DC voltage maintenance as the control target. After detecting the phase loss fault of the generator, the blocking fault corresponds to the trigger pulse of the rectifier bridge connected to the whole set of three-phase windings, and the remaining three rectifier bridges are connected in parallel to provide the DC voltage to the load, and the trigger angle of the remaining three sets of rectifier bridges is adjusted to balance the output DC current of each bridge. The simulation and experimental results of a 100kW 12-phase permanent magnet synchronous generator controlled rectifier system operating under normal, phase loss and fault tolerance conditions are compared and analysed. The designed control method can effectively reduce the DC current imbalance and improve the DC power supply quality.

Matrix Extraction of Parasitic Parameters and Suppression of Common-Mode Conducted Interference in a PMSG-IDOS Rectifier Module

The rectifier module is the key part of a permanent magnet synchronous generator integrated DC output system (PMSG-IDOS) with low-voltage and high-current. The high-speed switching device of the rectifier module is the main source of electromagnetic interference (EMI). In this paper, the matrix extraction method is proposed to establish an accurate conducted interference model, and a 3D crimped SiC MOSFET model is established via Ansoft Q3D simulation software. The matrix of the parasitic parameters between poles of the MOSFET is simulated to extract the accurate parasitic parameters. Furthermore, a high-precision conducted interference simulation model of the pulse width modulation (PWM) rectifier system is established. Then, the space vector pulse width modulation (SVPWM) jump-backward control strategy based on the three-phase four-leg structure is proposed to suppress the common-mode interference, and the comparison with other two methods is carried out based on this model. Finally, the experimental platform of a 5 V/1000 A synchronous generator with rectifier is constructed, and conducted interference is tested in accordance with the simulated results. It demonstrates the accuracy of the model with parasitic parameters based on the matrix extraction method. This paper provides a more simple and effective reference method for the prediction study of conducted interference in power converter systems. After comparing the simulation results with the experimental results, it is proven that the SVPWM jump-backward control strategy based on the three-phase four-leg structure can ensure the output balance of the bridge leg and allow the common-mode (CM) interference to reach the ideal state.

Impedance Modeling and Stability Analysis in Vehicle-Grid System with CHB-STATCOM

Recently, the low-frequency oscillation (LFO) frequently happens in the vehicle-grid system of high-speed railways when electric multiple units (EMUs) are put into operation. As a possible solution, a single-phase cascaded H-bridge static synchronous compensator (CHB-STATCOM) directly connected to the traction network is applied to dynamically compensate the reactive power of vehicle-grid system. This paper focuses on the impedance modeling and stability analysis in the vehicle-grid system with CHB-STATCOM. Firstly, the vehicle-grid system is simplified to a single-phase rectifier with large grid inductance. The accurate dq -frame impedance of the rectifier system with CHB-STATCOM is derived in detail. Secondly, through the generalized Nyquist stability criterion (GNSC), the influence of CHB-STATCOM and its different control parameters on the stability of rectifier system is revealed. Thirdly, the excellent performance of CHB-STATCOM in suppressing the LFO and the accuracy of theoretical analysis are verified via time-domain simulations. Finally, to further verify the effectiveness of CHB-STATCOM in real applications, a dSPACE based controller hardware-in-the-loop (HIL) simulation platform is established, which includes the physical control circuits of eight EMUs. The experimental results show that the CHB-STATCOM has a good dynamic compensation effect and can efficiently suppress the LFO.

An Improved Open-Switch Fault Diagnosis Technique of a PWM Voltage Source Rectifier Based on Current Distortion

Numerous studies show that power semiconductors are significant contributors to the overall failure rate of pulsewidth modulation (PWM) voltage source rectifier (VSR) systems. Aimed at this problem, this paper presents an improved diagnosis system for open-circuit faults of a three-phase PWM VSR based on ac current distortion characteristics, which consists of a diagnosis module, a register module, and a decision module. The diagnostic module employs a hysteresis comparator to judge the change trend of the currents, and thereby diagnoses the single open-circuit (OC) faults. The register module is employed to achieve multi-switch OC fault diagnosis, and the decision module is used to output the final result. The proposed method extends the previous work to multi-switch OC fault conditions as well as improves the diagnosis accuracy. The experimental results show that the proposed method can correctly achieve fault diagnosis, including 6 kinds of single-switch faults and 15 kinds of different double-switch faults. Additionally, the proposed method also shows superior anti-interference performance and high robustness under abrupt load transient conditions, different power factor conditions, unbalanced and/or distorted grid voltage conditions, and different ac filter structure conditions. Furthermore, the average diagnostic time of this method is only 3.68 ms.

Design and Research of Thyristor Rectifier Based on Polarization Technology

The thyristor rectifier has the advantages of simple operation, fast response, good steady flow accuracy and high rectification efficiency. In this paper, the system structure design and parameter design of the thyristor rectifier are carried out, and the main technical measures of the rectifier cabinet are analyzed. Through the research of the thyristor rectifier system, the system can obtain high stability DC current, which can basically meet the actual production needs.

A New Design and Analysis of Round-Shaped Transformers Supplying Diode and Controllable Rectifiers

This paper presents a new design of round-shaped transformers applied in diode and controllable rectifiers. Despite conventional three-phase transformers, in round-shaped transformers, voltage is induced on the secondary winding by rotating magnetic field. As a result, in the secondary of this transformer, there can be more than three phases with desired shifts. On the other hand, some rectifier systems may use more bridges supplying from the secondary to improve output dc voltage. However, the rectifier systems produce undesirable current harmonics, especially in controllable systems. This paper discusses how the new design of round-shaped transformers can significantly reduce the harmonic contents of the input current by sinusoidal skewing of the secondary core. The new design is investigated in this paper and its analysis confirms that the harmonics of the input currents can be effectively reduced. Experimental results are also provided to validate the analysis carried out in this paper.

Design Paradigm for Modular Multilevel Converter-Based Generator Rectifier Systems

Modular Multilevel Converters (MMC) are being widely considered for medium to high voltage DC applications. Designing such converters through multi-objective optimization is of interest because such an approach allows the trade-off between competing objectives (for example mass and loss) to be explicitly and quantitatively identified. In this work, an optimization based design paradigm for MMC based generator rectifier systems is proposed. Such development typically requires detailed component design and simulation models for the electric machine and converter which are computationally expensive. As an alternative, the proposed work utilizes an electric machine metamodel, inductor metamodel, and high-speed steady-state simulation model for the MMC to facilitate multi-objective optimization minimizing system metrics of interest while satisfying system constraints. A case study is undertaken to demonstrate the functionality of the proposed design paradigm.

Thermally Activated ReBCO Switches for Charging High-Current Magnets

Aiming at design improvements for the International Axion Observatory, alternative options for powering of the 20-kA magnet are under consideration. Use of high-Temperature superconductors in a transformer-rectifier system cooled by a single stage cryocooler at 40 K-50 K level is a promising option, which allows to avoid massive movable bus bars, current leads, and related services. The overall efficiency of such a magnet powering system is determined by the characteristics of high-current switches, which have to operate in a fast synchronous manner. We studied the performance of thermally activated superconducting switches made of adjusted 4-mm-wide ReBCO tapes, using etching of the tapes in a FeCl-3 bath to increase their resistance in normal state and to prepare low-mass heaters perfectly matching the tape surface. First experimental results on the 'off' state performance and time constants of the switches, when toggling between 'on' and 'off' states, are presented. Finally, we discuss a conceptual design of an all-ReBCO rectifier system comprising a superconducting transformer and thermally activated switches, which can be scaled up for charging large magnet systems like particle detector magnets where slow charging is feasible.

Application of Active Disturbance Rejection Controller in Three-Phase PWM Rectifier

For the three-phase voltage type PWM rectifier which is a strong nonlinear, a strong coupling and time-varying system, a double-loop control structure of DC voltage outer loop and current inner loop is designed to control it. In practice, the traditional PID controller is commonly used. However, it is relatively sensitive to changes in system parameters and the control effect is not ideal. This paper proposes to use the auto disturbance rejection control instead of the traditional PID control. The auto disturbance rejection controller is based on the improvement of the PID controller. It inherits the core concept of PID error feedback control. And it solves the problem of contradiction between response fastness and overshoot by using a processing method that arranges a transition process. I compare the results of the two controllers by simulation, which proves that the scheme of auto disturbance rejection control is more suitable for the PWM rectifier system than the traditional PID control. The auto disturbance rejection controller has better dynamics, stability, and faster response times.

Open-Switch Fault Diagnosis Algorithm and Tolerant Control Method of the Three-Phase Three-Level NPC Active Rectifier

This paper proposes a fault diagnosis and tolerant control methods for an open-switch fault caused in a three-phase three-level neutral-point-clamped (NPC) pulse-width modulation (PWM) active rectifier. The open-switch fault in the three-level NPC active rectifier causes a distortion in the input phase current and a ripple in the DC-link capacitor voltage. Therefore, proper fault diagnosis and tolerant control methods are required to prevent additional failures and performance degradation in the rectifier system. This paper conducted a detailed analysis of the effect of the single open-switch fault on the NPC PWM active rectifier and proposed a fault diagnosis method utilizing the DC link voltage and the phase angle of the input grid voltage. Furthermore, this paper proposes a fault-tolerant control method to reduce the effect of the open-switch fault by compensating a distorted reference voltage. The effectiveness of the proposed fault diagnosis and tolerant control methods are verified through experimental results.

Tunneling Magnetoresistance and Spin-Dependent Diode Performance in Fully Epitaxial Magnetic Tunnel Junctions With a Rocksalt ZnO/MgO Bilayer Tunnel Barrier

Metal/insulator/metal (MIM) tunnel diodes are promising for high-frequency rectifier systems, such as for energy harvesting in the infrared-to-terahertz range, where typical semiconductor devices cannot operate. For practical applications, though, better rectification is needed. The authors fabricate fully epitaxial Fe/ZnO/MgO/Fe tunnel junctions exhibiting 96% magnetoresistance at room temperature, as well as greatly enhanced rectification performance, due to magnon excitations at the Fe/barrier interfaces. This is an exciting result for energy harvesting at longer wavelengths.

Design of a Three-Phase Bidirectional PWM Rectifier with Simple Control Algorithm

Abstract The paper covers the main aspects of designing a low voltage three-phase PWM rectifier for bidirectional AC/DC power flow with unity power factor. A model in Matlab/Simulink environment has been built for a 10kW active rectifier with an LCL filter connected to grid side of the rectifier. The primary goal of the model is to achieve low grid current harmonic content for frequency ranges described in worldwide applicable standards and above. LCL filter parameter design procedure is described in the paper and implemented in the rectifier model to achieve a better power quality with limitations in passive element size. A simple “p-q” theory-based voltage oriented control algorithm is used in the model and described in the present paper. Model performance is characterised by dynamic response, stability and grid parameters during simulation. The simulation results demonstrate that the modelled rectifier system is stable and the grid current harmonic content is low both in the low-and high-frequency ranges.

Control Strategy for a Multiphase Lundell-Alternator/Active-Rectifier System in 14 V Automotive Power Systems

This paper presents a novel control strategy for a conventional six-phase Lundell alternator fed at the output with a MOSFET-based active rectifier. The signal references for the controller are calculated from a cost-function aiming to minimize the alternator stator copper losses in an effort to maximize the alternator–rectifier system overall efficiency. The system is initially simulated and tuned in MATLAB/Simulink and then experimentally verified. The steady-state efficiency results from experimental measurements of the alternator/rectifier system are compared against a standard passive rectifier. The results indicate a better overall efficiency compared to the passive rectifier, for an alternator speed of up to approximately 5000 rpm, corresponding to city driving.

Control Strategy to Compensate for Current and Voltage Measurement Errors in Three-Phase PWM Rectifiers

This paper introduces a compensation strategy to deal with both current and voltage measurement errors in the three-phase pulsewidth modulated rectifier system. The dc offset and scaling errors in the voltage and current measurements cause the injection of undesired dc and unbalanced currents into the three-phase input current and subsequently lead to voltage ripple at the dc output voltage. This paper proposes a compensation scheme for current measurement error where the dc offset and scaling errors in the current measurement are estimated from the characteristic of the dc output voltage ripple combining with simple band-pass and low-pass filters. Meanwhile, an advanced current controller designed with a proportional integral plus two resonant controllers tuned at the fundamental grid frequency $({{\omega _s}})$ and $2{\omega _s}$ in the synchronous ( d–q ) reference frame is suggested to reject the impact of the dc offset and scaling errors in the voltage measurement. The proposed compensation method is developed without the need of extra hardware circuit, sensor, or precise information of system parameters so that it can be considered as more cost-effective and robust solution. The effectiveness of the proposed solution is verified by experimental results.

Background harmonic modeling and harmonic contribution assessment for large-power industrial supply system

The large-power rectifier system injects numerous harmonics into the public grid, which results in serious effects on the power quality at the point of common coupling (PCC). The two methods, (1) establishment of the accurate probabilistic model for the background harmonics and (2) assessment of the harmonic contribution, are beneficial for evaluating the impact of the harmonics generated by the power consumer on the power grid. First, the background of the power supply system and the harmonic distribution at the PCC are introduced, based on the measured data in the electrolytic manganese factory. The probability distribution of the harmonic voltage during the specific discontinued day is fitted by means of the normal distribution, the lognormal distribution and the Weibull distribution. The goodness-of-fit is obtained by Kolmogrov-Smirnov test method, and the optimal fitting function is identified. The simulation model of the background harmonic voltage is thus built. Finally, the harmonic contribution of the rectifier system on the production day is assessed based on the simulation model. The results show that, the negative harmonic contribution is dominating.

Система «Трехфазный МЭГ – мостовой выпрямитель» с дополнительным дросселем в нейтрали: определение режимов работы и условий их существования

Система «Трехфазный МЭГ – мостовой выпрямитель» с дополнительным дросселем в нейтрали: определение режимов работы и условий их существования

Analysis and design of a class E current-driven rectifier for 1 MHz wireless power transfer system

Abstract The paper presents the design of the class E current-driven rectifier, which is intended for operation in the wireless power transmission system, as well as the concept of selection of the rectifier parameters which allows the operation with high efficiency. The selection of the rectifier parameters was performed with a view to the use of the existing wireless power transmission (WPT) system. The procedure for selection of the rectifier parameters has been proposed to enable its optimal use in reference to the system parameters given already at the design stage, ie; load resistance and the coil magnetic coupling factor (distance between coils). In order to verify the correctness of the procedure for selection of the parameters, the numerical model of the system which consists of the class E resonance inverter, the air-core transformer and the designed E class rectifier system was developed in the LTspice environment. Simulation tests and analysis of the obtained calculation results were performed. Based on the simulation results, a prototype of the class E rectifier system which cooperates with the existing wireless power transmission system supplied from the class E inverter was developed. The obtained results of laboratory measurements demonstrated a high compliance with the simulation results, thus, confirming the correctness of the proposed design procedure and the high operating efficiency of the rectifier system.

Open Switch Fault Diagnosis Method for PWM Voltage Source Rectifier Based on Deep Learning Approach

With the development of machine learning technology, numerous studies have been proposed to diagnose the open circuit (OC) faults in the pulse width modulation (PWM) voltage source rectifier (VSR) systems. However, most methods require system signals of more than one current period, which show poor real-time performance. Aiming at this problem, this paper presents an improved diagnosis system based on deep belief networks (DBN) and least square support vector machine (LSSVM). First, the double chain quantum genetic algorithm (DCQGA) is employed to obtain the proper length of measured signals and DBN structure parameters. Then, the fault features are extracted from the signals through DBN. Finally, these features are used to train the LSSVM fault classifier to construct the diagnosis model. The experimental results show that the proposed method can achieve the fault diagnosis including six kinds of single switch faults and 15 kinds of different double switches faults correctly. Besides, the proposed method also shows the superior anti-interference performance and high robustness on abrupt load transient conditions, unbalanced, and/or distorted grid voltage conditions, as well as, different power factor conditions. Furthermore, the average diagnostic time of this method is only 2.57 ms.

A New 24-pulse Rectifier Transformer with Delta-extended Connection

The low-voltage distribution system is influenced by ever-increasing harmonics caused by nonlinear loads. A simple and reliable 24-pulse rectifier transformer for high-current and low-voltage is proposed in this paper. The proposed 24-pulse rectifier transformer consists of four secondary windings in which an original delta-extended connection is adopted. First, the existing 24-pulse rectifier system is analyzed. Second, the topology, the phase-shifting principle, the input current and the output voltage of 24-pulse transformer are described. Finally, the simulation results validate the theoretical analysis and the advantages of the new 24-pulse rectifier transformer in multi-pulse rectifier areas.