Phase-controlled Rectifier Research Articles

The Scheme of Movable DC Ice Melting Device Based on the Engine-Generator Topology

In this article, an entire scheme of DC ice-melting devices based on the engine-generator topology is proposed to solve the problem of poor portability caused by the current devices. It is found that the engine-generator topology suffers from a power mismatch when starting with load, which may eventually lead to starting failure. A soft-start strategy is proposed to control the power required by the load by controlling the duty cycle of the switching tube to achieve real-time power matching. Compared with the most popular phase-controlled rectifier DC ice melting device, the entire scheme of the device is proposed, which not only achieves continuous voltage and current adjustment but also effectively reduces the ripple of the output and control complexity. The feasibility of the proposed soft-start strategy and the entire scheme of the device is verified by simulation results.

Open-Circuit Fault Diagnosis of Power Rectifier Using Deep Convolutional Neural Network

Aimed to automatically provide accurate fault diagnosis of data from failed power electronics, various studies have been researched based on different approaches. Recently, data driven methods based on deep learning have required increasing attention because of their automatic feature learning abilities. Nonetheless, one of the challenges using these methods in practice is how to obtain the most representative fault features and ensure the better predication performances at the same time. This paper is in respect of the open-circuit fault diagnosis of the phase-controlled three-phase full-bridge power rectifier using deep convolutional neural network (DCNN) for extracting and further classifying fault features. The process mainly includes four steps. Firstly, a presupposed approach of DCNN which is applied to automatically capture the paramount fault features from the raw data is briefly introduced. Then a structure of DCNN is designed to extract the features from output data. Furthermore, the model and framework of the fault diagnosis system are developed to diagnose the open-circuit fault of the power rectifier. Finally, the effectiveness of the proposed method is validated using simulation results. Experiments illustrate that the DCNN model can achieve high accuracy in different fault cases and present great capability of diagnosing fault types in open-circuit fault of power rectifiers.

Study on the Control System of the Phase Controlled Rectifier for Mine

In order to meet the requirements of different voltage rating of different electric equipment in coal mine and the requirement of voltage stabilizing for equipment use. A new type of phase control rectifier control system for mine is studied in this paper. The system has designed the control system based on the chip DSP software and the closed loop control system of the software PID. The experimental results show that the phase controlled rectifier control system can achieve a good phase shifting regulation for the rectifier output voltage, and control the output voltage of the trigger angle to meet the needs of the rated voltage of different electrical equipment, which is flexible and convenient. The software PID can adjust the closed loop according to the set value of voltage and current to meet the requirement of the rated power when the equipment is working normally. The result proves the effectiveness of the control system of the phase control rectifier, and has a good value in engineering application and popularization.

Conceptual design of 2 MJ capacitive energy storage

Abstract The conceptual design of the capacitive energy storage intended for operation in laboratory conditions is considered. This capacitive energy storage includes the capacitor cells of 200 kJ stored energy, each incorporating one self-healing high-energy-density capacitor, one semiconducting switch unit on the basis of Light Triggered Thyristors (LTT) and the pulse diodes, as well as the toroid inductor. Power supply of the capacitive energy storage is provided by high voltage (HV) 3 × 10 kV, 50 Hz industrial electrical network, using the HV power transformer and phase-controlled rectifier. Special design for the capacitor cell and the module of capacitor cells is proposed, which provides easy access to all components of the capacitor cells during operation and maintenance. Control system of the capacitive energy system has a hierarchic structure and includes programmable logic controller (PLC), programmer for non-synchronous triggering of capacitor cells discharges and data acquisition system.

Power supply for generating frequency-variable resonant magnetic perturbations on the J-TEXT tokamak

To further research the response of the tearing mode (TM) to dynamic resonant magnetic perturbation (DRMP) on the J-TEXT tokamak, a modified series resonant inverter power supply (MSRIPS) with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor (IGBT) full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier (SCR) switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak.

Open-circuit fault diagnosis of power rectifier using sparse autoencoder based deep neural network

Abstract This paper is concerned with the open-circuit fault diagnosis of phase-controlled three-phase full-bridge rectifier by using a sparse autoencoder-based deep neural network (SAE-based DNN). Firstly, some preliminaries on SAE-based DNN are briefly introduced to automatically learn the representative fault features from the raw fault signals. Then, a novel strategy is developed to design the structure of the SAE-based DNN, by which the depth and hidden neurons of the SAE-based DNN could be regularly determined to extract the features of input signals. Furthermore, the fault model and system framework are presented to diagnose the open-circuit fault of the three-phase full-bridge rectifier. Finally, the effectiveness of the developed novel strategy is verified by the results of simulation experiments, and the superiority of the novel SAE-based DNN is evaluated by comparing with other frequently used approaches.

Fast calculation method for rectifier matrix model and its application in optimised control of SAPF for network‐wide harmonic suppression

The conventional control strategies of shunt active power filter (SAPF) normally focus on the compensation for local non-linear loads, which may become uneconomical with a number of distributed non-linear loads. For an optimised network-wide harmonic suppression method, harmonic power flow calculation is the basis, and non-linear load modelling is the key which affects the accuracy and efficiency. First, this study discussed an accurate, but complicated non-linear load model, the coupled admittance matrix model for a typical harmonic source, phase-controlled rectifier, in detail, and proposed a fast calculation method which can simplify the calculation process evidently and explain the variation rules of model parameters clearly. Second, the main harmonic coupling characteristics of the rectifiers are analysed based on the calculation method, thus the rectifier matrix model is simplified and then an impedance-based network harmonic model for networks with distributed rectifiers is established. Finally, based on the network model, a promising control strategy of SAPF for network-wide harmonic suppression is presented, by which network parameters are acquired by online impedance measurement technique and good compensation performance is assured by the proposed network model. Experimental results and simulations are provided to validate the effectiveness of the proposed methods.

Design and Implementation of Three-phase Resonant DC-DC Power Converter for Low-voltage High-current Applications

—The most commonly employed DC power supply in industrial processes, such as chemical electrolysis, aluminum potlines, DC arc furnaces, graphitizing furnaces, copper refining, plasma torches, the starting process of aircraft, the large Hadron collider, and nuclear fusion, is a magnetic confinement approach based on a line frequency isolated transformer with a phase-controlled rectifier. These power supplies suffer from high conduction losses, low efficiency, large size, and heavy weight. In this article, a high-frequency isolated three-phase resonant DC-DC converter is proposed for high power applications that demand low voltage, isolation, good regulation against load and line disturbances, and fast dynamic response. The modeling, control, and design of the proposed converter are carried out under symmetrical control with fixed frequency operation, and its steady-state analysis has been presented according to the description of the operational stages of the converter. Mathematical modeling of the LLC resonant tank network is presented, and its design curves are plotted against a variation of normalized frequency for different values of load. Based on mathematical analysis, a 5-V/150-A prototype model has been built and tested under various operating conditions, and the obtained experimental results are presented.

3상 위상제어 정류기를 위한 DVR의 반응시간 최적화

In this paper, we present optimization technique for the response time of DVR (Dynamic Voltage Restorer) and the possible compensation range of voltage dip by the DVR system. To protect 3-phase phase-controlled rectifier from voltage dip, DVR system needs to have optimum response time as an important design factor. Although the fast response time of DVR ensures wider range of voltage dip, DVR controller has so high cost and poor stability. This paper proposes DVR system with optimum response time required for certain intensity of voltage dips and good stability to support possible compensation range of voltage dip. Proposed technique showed optimum response time and good stability for overall system. We believe that proposed technique is reliable and useful in DVR design.

Line-frequency phase-controlled rectifiers with adaptive digital controllers

This article deals with the influence of PI controller linear gain scheduling on the dynamic characteristics of the line-frequency phase-controlled rectifier. The examined device has digital control electronics of the DRI 07B type, based on the Intel 80C196 microcontroller. The realized adaptive PI controllers utilize wide variations of the current gain (Kp), decreasing linearly in proportion to the increase in the rectifier output current in the area of the discontinuous currents. Reaching the threshold of the rectifier's discontinuous current, the current gain of the PI voltage controller remains constant. Beside the improvement of the thyristor rectifier's static stability during operation with small output currents, implementation of the adaptive PI control also led to improvement of the voltage controller response in the case of load disturbance in the range of 13-90 % of the nominal rectifier output current. Transfer functions were analyzed for specific parts of the phase-controlled rectifier DRI 110-100 having nominal output parameters of 116 V and 100 A. The values of the relative damping and root-locus characteristics were analyzed in detail.

A Study on the Reliability of DVR in a 3-Phase Phase-Controlled Rectifier

This study investigated the relationship between the response time of DVR (Dynamic Voltage Restorer) and the possible compensation range for voltage dips by the DVR system which protects the 3-phase phase-controlled rectifier from said dips. As a result, the permissible range of voltage dip is presented in a 3-phase phase-controlled rectifier. When the DVR compensates for voltage dip, the range of voltage dip can be compensated according to the DVR"s response time. Using the proposed method, DVR response time can be determined from the parameters of the 3-phase phase-controlled rectifier and the possible compensatory range of voltage dip, while at the same time it is possible to use a control system having an appropriate speed. Therefore, the use of excessively fast equipment can be avoided, improving the stability of the overall system. The reliability of the DVR concerning the 3-phase phase-controlled rectifier can be verified by simulation.

Interrupting Short-Circuit Direct Current Using an AC Circuit Breaker in Series with a Reactor

This paper describes and demonstrates the principle and efficacy of a novel direct current fault interruption scheme using a reactor in series with a controlled rectifier and a conventional AC circuit breaker. The presence of the series reactor limits the capacitive discharge current from the DC filter capacitor at the output terminals of the phase-controlled rectifier. In addition, the series reactor along with the filter capacitor forms an underdamped series RLC circuit which forces the fault current to oscillate about zero. This synthetic alternating current can then be interrupted using a conventional AC circuit breaker. The selection criteria for the series reactor and overcurrent protection are presented as well. Using the proposed scheme for an example case, a DC fault current magnitude is reduced from 56 kA to 14 kA, while the interruption time is reduced from 44 ms to 25 ms.

MITIGATION OF HARMONICS USING THYRISTOR BASED 12 PULSE VOLTAGE SOURCE PWM RECTIFIER

Three-phase thyristor rectifiers have been used in industries for obtaining a variable dc voltage, but they have a problem of including large lower-order harmonics in the input currents. For high-power applications, a 12-pulse configuration is useful for reducing the harmonics, but it still includes the (12m ± 1) th (m: integer) harmonics. In order to further reduce the harmonics, this paper proposes to supply a ramp wave voltage at the input of a 12-pulse phase-controlled rectifier. Theoretical investigation to reduce harmonics is presented, and a strategy to control the regulated voltage and unity power factor at input side based on 12 pulse modulation technique. This paper discuss the impact of using 3-phase and 12-pulse rectifier circuit commonly found in unity power factor at input ac mains and regulate output voltage. The 12-pulse topology is known to be more expensive, but produce the least input current harmonics. However, the latter statement is completely true under balanced line conditions. In practice, the lines are inherently unbalanced. Hence, the question of whether the 12-pulse rectifier will indeed perform better in terms of the harmonics injected to the line is still under on-going discussions. This presents the modelling and simulation of both rectifier topologies to compare their input current and regulated output voltage harmonics. The rectifiers are modelled using the MATLAB/SIMULINK simulation model and several common cases conditions will be simulated to compare their harmonic levels.

POWER EFFICIENCY AND DIGITAL COMMUNICATION OF PHASE-CONTROLLED RECTIFIERS FOR INDUSTRIAL UNINTERRUPTIBLE POWER SUPPLY SYSTEMS

In this paper are presented line-frequency phase-controlled rectifiers with digital control units developed in Institute 'Nikola Tesla'. Digital control units of the type 'DRI 07' are based on microcontroller 'Intel' 80C196KB16. Implemented technical solutions are described, with emphasis on capabilities to establish digital communication with a central process computer implementing standard industrial communication protocols. Electrically isolated 'half-duplex' serial communication of RS-485 standard enables easy connection of numerous, mutually remote rectifiers with one programmable logic controller adjusted for the conversion of communication protocols, also as further proceeding of data on the state of all rectifiers in a facility to the process control system. Results of the examinations of power factor, total current harmonic distortion and overall efficiency are presented. Comparison of procured results with corresponding data related to the rectifiers made by the leading west-European manufacturers. On phase-controlled rectifier rated for 90 kVA, loaded with 50% of its nominal current, overall efficiency of at least 96.6% was measured.

Auxiliary Supply Assisted Harmonic Suppression for 12-Pulse Phase-Controlled Rectifiers

A 12-pulse phase-controlled rectifier consists of two sets of 6-pulse rectifiers. It is found that harmonic distortion of the input current is minimized if dc currents of the two rectifiers are in a boundary between continuous and discontinuous conduction modes. In order to realize the boundary mode operation under any load conditions an auxiliary voltage supply (AVS) is introduced. The AVS is required a bi-directional power flow but its handled net power is quite small. Capacity of AVS is less than 10% of rated rectifier output. A simple AVS arrangement is proposed and the usefulness is verified by simulation and experimental results.

Auxiliary Supply-Assisted 12-Pulse Phase-Controlled Rectifiers With Reduced Input Current Harmonics

Three-phase thyristor rectifiers have been used in industries for obtaining a variable dc voltage, but they have a problem of including large lower-order harmonics in the input currents. For high-power applications, a 12-pulse configuration is useful for reducing the harmonics, but it still includes the (12 m plusmn1)th (m: integer) harmonics. In order to further reduce the harmonics, this paper proposes to insert an auxiliary supply producing a square wave voltage to the dc bus of a 12-pulse phase-controlled rectifier. Theoretical investigation to reduce harmonics is presented, and a strategy to control the auxiliary supply voltage based on pulse-width-modulation is proposed. Reduction in the current harmonics is verified by simulation and experimental results. The volt-ampere (VA) rating of the auxiliary supply is about 5% of the rectifier output.

Current-source-rectifier topologies for sinusoidal supply current: theoretical studies and analyses

For current-source-rectifier (CSR)-based systems, sinusoidal supply current and unity displacement power factor in the utility are achieved through either a pulsewidth-modulation CSR or a phase-controlled rectifier in conjunction with an active filter. This paper investigates theoretical studies and analyses for the two topologies from the standpoint of converter kilovoltampere rating and switch rating.

3상 위상제어 정류기에서 DVR의 응답시간과 허용 가능한 순시저전압의 범위에 대한 연구

It is investigated that the relation between the response time of DVR(Dynamic Voltage Restorer) and the possible compensation range of voltage dip by the DVR system which protects the 3-phase phase-controlled rectifier from voltage dip. As a result, the permissible range of voltage dip is presented in the 3-phase phase-controlled rectifier, and it is presented that the range of voltage dip which can be compensated according to the DVR s response time. when the DVR compensates voltage dip, Using the proposed method, the DVR s response time can be determined from the parameters of 3-phase phase-controlled rectifier and the possible compensation range of voltage dip, and it is possible to use the control system which have an appropriate speed. Therefore, the use of excessively fast device can be avoided, and the stability of the overall system is improved. Also the reliance of DVR about the 3-phase phase-controlled rectifier can be verified.

Brushless permanent magnet (BPM) motor drive system using load-commutated inverter

The goal of this work is to develop a brushless permanent magnet (BPM) motor drive system with low total system cost, high reliability and adequate performance for high-volume production and application to commercial appliances. The power converter used is a low-cost thyristor-based load-commutated inverter (LCI). Although LCIs have been used to supply sinusoidally excited permanent magnet motors, their application to BPM motors is a key contribution of this work. A detailed digital computer model capable of predicting the steady state as well as the transient performance of a BPM motor driven by an LCI has been developed. The utility-side phase-controlled rectifier, as well as the motor-side inverter-including the DC-link inductor, are modeled. A load-commutated inverter specifically designed to supply the BPM motor has been fabricated in the laboratory. The developed control strategy has been implemented on an INTEL 80C196KD microcontroller board. Simulation and experimental results to support the use of an LCI to drive a BPM motor are included in the paper.

Estimation of speed and armature temperature in a brushed DC drive using the extended Kalman filter

Closed-loop speed control of a DC drive requires a rotor-speed feedback signal which can be obtained using a speed measuring device. However this device adds to the cost of the drive and the number of electrical connections to the motor. The paper describes a method of speed estimation using armature voltage and current measurements that eliminates the speed measuring device. By including thermal effects in the estimation process the effect of temperature variations on the speed estimte are minimised and an estimate of average armature temperature is produced. An extended Kalman filter observer for real-time estimation of speed and armature temperature is formulated using electrical, mechanical and thermal models of the motor. The observer is implemented using a TMS 320C30 digital signal processor system. A range of experimental results demonstrating the observer's steady-state and transient performance is presented for the particular case of a 3 kW machine with constant field current supplied from a phase-controlled rectifier, although the estimation method is applicable to DC drives of any power rating and configuration.