Rectifier Control System Research Articles

Research on VIENNA rectifier QPR control and soft start

The principle and operation of the VIENNA rectifier is examined and the VIENNA mathematical model is developed. To address the issue that the three-phase VIENNA rectifier’s double PI controller finds it challenging to attain both rapidity and accuracy, a double closed-loop control approach consisting of inner loop quasi-proportional resonant control (QPR) and outer loop PI control is created. Aiming at the problems of inrush current on the grid side and DC bus voltage overshoot caused by the VIENNA rectifier in the startup process, the paper makes a theoretical analysis and designs a soft startup strategy. Then, the simulation model of the three-phase VIENNA rectifier control system was built in Simulink, which verified the correctness of the QPR control strategy and soft start scheme. Finally, an 8-kW prototype is set up, and the experimental results further confirm the effectiveness of the slope setting of the current.

Dynamic performance enhancement of nonlinear AWS wave energy systems based on optimal super-twisting control strategy

This paper presents a Super-Twisting Algorithm (STA) sliding mode control technique as an alternative to the conventional Proportional-Integral (PI) control system. This application is specifically in the context of a nonlinear Archimedes Wave Swing (AWS) device, which functions as a wave energy converter system (WECS) connected to the power grid. The main goal is dynamic performance enhancement of such wave energy systems under network disturbances. Two STA controllers areessential for the rectifier control system in the grid-connected system to capture the most power from waves while limiting losses in the AWS linear generator. In addition, four STA controllers are incorporated into the inverter control loop to preserve the DC link and common coupling voltages at the preset values. The Honey-Badger Algorithm (HBA) is applied for the optimization of gain parameters of the STA controllers, which are compared to the PI gains adjusted using the coot, the hybrid augmented grey wolf optimizer and cuckoo, and PSO search techniques to assess the worthiness of adopting this new control approach. The grid-connected AWS experiences a variety of faults, includingsymmetrical and unsymmetrical faults with successful and unsuccessful breaker reclosures. Finally, the system is experimentally validated using the OP4510 real-time simulator. The experimental results reveal that the HBA-STA controllers outperformPI controllers in omitting fluctuations in the regulated variables, making the STA a strong contender as a control method.

Feedback Linearization Sliding Mode Control Strategy for Three-Phase Voltage PWM Rectifier Based on New Variable Speed Reaching Law

Three-phase voltage PWM rectifier is a multivariable, strong coupling, nonlinear multi-input and multi-output system. In the design of rectifier control systems, with PI control it is difficult to achieve the ideal control effect, the dynamic performance is poor, and the parameter computation is complex. Moreover, the traditional sliding mode control voltage outer loop suffers from the problem of chattering, which is difficult to solve. Responding to the above issues, a new type of variable speed reaching law is proposed, which is applied to the voltage outer loop sliding mode control, while the feedback linearization principle is introduced to the current inner loop, and a new type of double closed-loop sliding mode control system is obtained by applying the two theories to the design of the sliding mode controller. A simulation model is established in MATLAB/Simulink to compare the PI control, the SMC control and the V-SMC control strategy proposed in this paper (voltage outer loop V-SMC current inner loop FLC-SMC control), and the simulation results show that the rectifier under the new dual-closed-loop sliding mode control strategy has the advantages of good dynamic performance, strong robustness and strong anti-interference ability. At the same time, compared with the traditional sliding mode control strategy, the vibration suppression effect under the proposed control strategy is obvious. Finally, a 10 kW rectifier control system is built on a semi-physical hardware-in-the-loop experimental platform to further verify the correctness and superiority of the proposed control strategy.

Co-Design of the Control and Power Stages of a Boost-Based Rectifier with Power Factor Correction Depending on Performance Criteria

Rectifiers with power factor correction are key devices to supply DC loads from AC sources, guaranteeing a power factor close to one and low total harmonic distortion. Boost-based power factor correction rectifiers are the most widely used topology and they are formed by a power stage (diode bridge and Boost converter) and a control system. However, there is a relevant control problem, because controllers are designed with linearized models of the converters for a specific operating point; consequently, the required dynamic performance and stability of the whole system for different operating points are not guaranteed. Another weak and common practice is to design the power and control stages independently. This paper proposes a co-design procedure for both the power stage and the control system of a Boost-based PFC rectifier, which is focused on guaranteeing the system’s stability in any operating conditions. Moreover, the design procedure assures a maximum switching frequency and the fulfillment of different design requirements for the output voltage: maximum overshoot and settling time before load disturbances, maximum ripple, and the desired damping ratio. The proposed control has a cascade structure, where the inner loop is a sliding-mode controller (SMC) to track the inductor current reference, and the outer loop is an adaptive PI regulator of the output voltage, which manipulates the amplitude of the inductor current reference. The paper includes the stability analysis of the SMC, the design procedure of the inductor to guarantee the system stability, and the design of the adaptive PI controller parameters and the capacitor to achieve the desired dynamic performance of the output voltage. The proposed rectifier is simulated in PSIM and the results validate the co-design procedures and show that the proposed system is stable for any operating conditions and satisfies the design requirements.

Investigation of the control system of a three-phase active voltage rectifier

Investigation of the control system of a three-phase active voltage rectifier

Influence of System Harmonics on Digital Rectifier Control System and its Solution

Influence of System Harmonics on Digital Rectifier Control System and its Solution

The efficiency of the active controlled rectifier operation in the mains voltage distortion mode

Goal. Checking the efficiency of the active rectifier with differences types of control systems in conditions of deep voltage distortions of a three-phase three-wire supply network. Methodology. The authors have used the Matlab/Simulink software environment to create a model of an active rectifier with various types of control systems as part of a frequency electric drive. We performed a series of simulations of the operating modes of an active rectifier with various control systems when the supply voltage is distorted. Results. When the active rectifier is operating in an unregulated mode, the distortions of the current and mains voltage exceed the maximum permissible values. The quality indicators of the mains current and mains voltage are significantly higher than the normally permissible values. In the absence of voltage distortions in the supply network, the operation of the active rectifier can effectively eliminate the distortions of the mains current, regardless of the type of control system of the active rectifier. In conditions of deep distortions of the supply network voltage, the operation of an active rectifier with a vector control system is more efficient than with a parametric control system. Originality. Criteria for determining the quality of consumed electricity at the connection point of the circuit are proposed. Practical significance. Recommendations have been developed for the use of active rectifier control systems when working with a distorted power supply voltage.

Бортовая система электроснабжения для электрических самолетов

The development of electric aircraft, the design of which will use, apart from doing away with pneumatic and hydraulic transmissions, electric propulsion, is one of promising lines in aviation technology. As an example, the project of the X-57 Maxwell electric aircraft developed by NASA, which is equipped with 14 propulsion electric motors, is given. In view of insufficient energy efficiency of existing storage batteries, a combined storage battery-and-generator power supply system for electric aircraft is considered. In the considered system, the aircraft propulsion is provided by electric motors, which are powered by storage batteries in combination with permanent magnet generators. The generator shaft is rotated by an auxiliary internal combustion engine, which operates in an economical mode. The power circuit of an active rectifier producing the +270 V DC bipolar output voltage is proposed, with which the permanent magnet generator operates with a sinusoidal phase current waveform and a close-to-unity power factor. The active rectifier control system uses an enhanced phase-locked loop, which eliminates the need to use generator rotor position sensors. For determining the stability domains and revealing undesirable hidden attractors in the considered storage battery-and-generator power supply system, it is proposed to use special analytical-numerical computation procedures based on modifications of Lyapunov's functions methods. The article will be of interest for developers of both aircraft and ground-based self-contained electric power supply systems with a bipolar 270 V DC voltage that must meet stringent requirements for improvement of their mass-and-dimensions and power performance characteristics.

Battery Charger for Hybrid Locomotive

<p><strong><span style="font-family: Times New Roman; font-size: small;">The paper introduces the concept and functionality of the battery charger – pulse rectifier control system for hybrid shunting locomotive. The locomotive producer is the company CZ LOKO a.s. The pulse rectifier operates in several modes including modes with charging of the traction battery from the alternator or from the distribution net, emergency mode or test modes. The paper presents the integration of the pulse rectifier into the context of the hybrid drive and the results of partial tests of drive control.</span></strong></p>

Grid-Voltage Sensorless Model Predictive Control of Three-Phase PWM Rectifier Under Unbalanced and Distorted Grid Voltages

The sensors in a three-phase pulse width modulation (PWM) rectifier control system are the basis of high-performance methods. Line voltage sensors are utilized to obtain information about the grid voltage amplitude and phase. To eliminate the grid voltage sensors and to decrease the cost of PWM rectifier control systems, various grid-voltage sensorless methods have been developed. In this article, a virtual-flux-based grid voltage estimation method is utilized in the model predictive control (MPC) of a PWM rectifier. The extended reactive power is introduced in the proposed MPC method; the MPC is then able to realize the control targets of eliminating input-side power oscillations and ensuring sinusoidal currents under unbalanced network conditions without any power compensation terms. The cascaded delayed signal cancellation (CDSC) method is applied to obtain the fundamental rectifier voltages in the virtual flux-based grid-voltage sensorless method. The proposed method can operate under unbalanced and distorted network conditions. Moreover, a startup current suppression method is applied in this method to avoid over-currents during the startup process. Experimental tests are performed to verify the effectiveness of the proposed method.

Real-Time Calculation Method of DC Voltage and Current to Eliminate the Influence of Signal Delay

In this study, the influences of the signal delay duration between rectifier and inverter in ultra-high voltage direct current (U-HVDC) transmission systems have been analyzed. The simulation results with different signal delay time under the same fault condition show that the signal delay time has a significant influence on the control system response during the fault and recovery periods. In the worst condition, it may lead to a commutation failure in the inverter. To eliminate the influence of the signal delay time on the DC control system, a fast calculation method for computing the voltage and current has been proposed by establishing the equivalent capacitance and inductance of the DC line. A voltage dependent current order limiter is added in the rectifier control system, which can calculate the DC current order value. Based on this concept, this paper proposes an improved control strategy to eliminate the influence of signal delay. The analysis and simulation results show that the calculation method can effectively improve the response speed and shorten the fault recovery time of the HVDC systems.

Управление полупроводниковым преобразователем изменением светового потока

Controlling the semiconductor device pnpn-structure switching-on moment by changing the illumination intensity opened the possibility to control the semiconductor structure switching-on delay moment. Such effect can be laid at the heart of a semiconductor converter direct control technology. With such technology, there is no need to have a synchronization unit in the rectifier control system, and it becomes possible to do away with using complex elements. It has been shown experimentally that there is no degradation in the rectifier operation reliability. Experimental data on the scatter in the adjustment characteristics of thyristors taken from the same batch are given. It follows from these data that there is a proportional dependence between the photocurrent and thyristor opening angle, and that there is a proportionality of the current adjustment range in different specimens. By applying the basic electric circuit used in the experiments and using the results from calculating the optothyristor control circuits for the specified output voltage adjustment range, it becomes possible to implement control of the rectifier output proportional to the setpoint (reference) signal. The obtained experimental results can be applied in practice and allow continuous operation modes to be realized, because no failures were recorded during the tests. The temperature drift of the characteristics can be compensated by operation of the control system’s negative feedback. No significant fluctuations of the rectified voltage were recorded, because this mainly depends on the initial control accuracy. The application of this control method is most relevant in high-voltage networks.

Improving of operation stability of frequency converters with active rectifiers in electric steel-making complex electrical equipment switching

Frequency converters with active rectifiers (FC-AR) are now used in rolling mill electric drives. Modern control systems of ARs are not adapted to voltage sags in power supply systems, which leads to converter tripping. The known methods of ensuring AR operation stability, such as kinetic buffering, correction signals based on negative sequence voltage and others, do not eliminate these emergency trips. As an additional measure the paper proposes the method of voltage sag compensation by using static var compensators (SVC) of electric arc furnaces (EAF) for parallel operation of frequency converters with active rectifiers and electric arc furnaces. However, it remains unknown how disturbances (such as overvoltages of switching of SVC harmonic filters (HF) and voltage sags during furnace transformer switching) affect operation stability of frequency converters with active rectifiers. All this makes it necessary to study the effect of these processes on the operation conditions of FC-AR and to improve the active rectifier control system. The authors used experimental arrays of instantaneous values of voltages and currents of the real-life complex «EAF-SVC» («Electric Arc Furnace – Statistic VAR Compensator») in this study. They also applied mathematical models of FC-AR with different PWM algorithms realized in Matlab-Simulink software. The main assumption of the model consists in using equivalent current sources modelling the operation of autonomous voltage invertors. An improved control system of AR has been developed. The main feature that distinguishes it from the known systems is the fact that it ensures operation stability during SVC harmonic filter and EAF transformer switching by using a signal conditioning unit for setting the active rectifier reactive current component as a function of power supply and AR input voltage difference. Implementation of the improved AR control system improves FC-AR stability during parallel operation with EAFs through reactive power consumption of the supply system. As a result, it reduces the amplitude of inrush current and voltage deviations in the DC-link of the FC-AR to the values lower than the setpoints of the AR protection system.

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.

Improved discrete sliding mode control strategy for pulse-width modulation rectifier

An improved sliding mode control utilizing repetitive control (ISMRC) is proposed for a three-phase pulse- width modulation (PWM) rectifier. The proposed controller integrates the advantages of both sliding mode control (SMC) and repetitive control (RC) by implementing a structure that embeds an RC controller into the equivalent control branch of an SMC controller. Both a simulation and an experiment are conducted to compare the proposed ISMRC controller with a conventional SMC controller. It is demonstrated that the fifth harmonic distortion of the current of the PWM rectifier system is controlled at 3.3%, the power factor is close to the unit, and the effect on the DC bus voltage is effectively restrained. Therefore, the proposed control strategy can improve both the steady-state performance and the dynamic transient response of a PWM rectifier control system effectively, as well as increase the robustness of the system to load disturbances and parametric uncertainties.

Simulation Study of Three - phase PWM Rectifier with Square of the Voltage Double Closed Loop Control

Based on the rotating coordinate system model, the mathematic analysis of the three-phase voltage-sourced PWM rectifier is carried out, and its feed-forward decoupling control strategy is studied. In order to realize the fast response of DC voltage and improve the dynamic and static performance of the rectifier, the double-closed-loop control of outer square of voltage loop and inner current loop is established. The control system of three-phase voltage-sourced PWM rectifier based on space vector modulation algorithm is designed. The simulation results demonstrate the designed model is accurate, and can achieve unity power factor control, DC voltage fast responses, and has not steady-state error.

Direct Power Control Strategy of PWM Rectifier Based on Improved Virtual Flux-Linkage Observer

In order to achieve the low cost and high performance control of three-phase PWM rectifier, a direct power control (DPC) strategy based on a new-style virtual flux-linkage observer is proposed. The model of three-phase PWM rectifier and the principle of virtual flux-linkage vector control are introduced firstly. Then, in order to avoid the effect of integral initial value and cumulative deviation, three first-order low-pass filters are cascaded to replace the pure integral link; an improved virtual flux-linkage observer of three-phase power grid is presented. From the observed virtual flux-linkage, the voltage and instantaneous power of three-phase power grid are online estimated. On this basis, the power grid voltage sensorless direct power control system of three-phase PWM rectifier is designed. Simulation results have shown that, both in the rectifying state and in the inverting state, the power grid side current and the DC side voltage of three-phase PWM rectifier all can be effectively controlled; the high power factor operation of three-phase PWM rectifier is realized.

Improved Virtual-Flux-Linkage Observation Method of PWM Rectifier

In order to improve the virtual flux oriented vector control performance of PWM rectifier, an improved observation method of virtual flux-linkage is proposed. To avoid the relevant problems of pure integrator, and to achieve the accurate observation of the grid voltage’s phase, three first order low-pass filters are cascaded to displace the pure integrator. Based on the SVPWM modulation module and the presented algorithm, grid voltage sensorless control system of three-phase PWM rectifier is given. Simulation results have shown that: either in rectifying or inverting status, the amplitude and phase of virtual flux-linkage can be observed accurately, i.e. the control system of PWM rectifier can operate reliably without the grid voltage sensors; the presented estimation method of virtual flux-linkage is effective.

Engine-Generator's Optimized Control Strategy for Electric Drive Armored Vehicle

By analyzing the enginegenerator units (EGU) work characteristics of electric drive armored vehicles, engine is controlled running along the optimum fuel curve. Voltage regulation of DC side and generator working condition are optimized through designing voltage space vector PWM (SVPWM) rectifier control system. Adopting rule-based method to solve the nonlinear problem during multi-power source coordination output, developed the multi-power source coordination output control strategy, satisfied the load power needs and the working state of the EGU is optimized.

Input AC Voltage Sensorless Control Scheme for a Three-Phase PWM Rectifier in Wind Power Generation System

In this paper, a sensorless control scheme for a three-phase bi-directional voltage-type PWM rectifier in wind power generation system that operates without the input AC voltage sensors (generator side) is described. The basic principles and classification of the PWM rectifier are analyzed, and then the three-phase mathematical model of the input AC voltage sensorless PWM rectifier control system is established. The proposed scheme has been developed in order to lower the cost of the three-phase PWM rectifier but still achieve excellent output voltage regulation, limited current harmonic content, and unity input power factor.