Implementation Of Current Control Research Articles

A dSPACE-based implementation of ANFIS and predictive current control for a single phase boost power factor corrector

This paper presents an innovative control scheme designed to significantly enhance the power factor of AC/DC boost rectifiers by integrating an adaptive neuro-fuzzy inference system (ANFIS) with predictive current control. The innovative control strategy addresses key challenges in power quality and energy efficiency, demonstrating exceptional performance under diverse operating conditions. Through rigorous simulation, the proposed system achieves precise input current shaping, resulting in a remarkably low total harmonic distortion (THD) of 3.5%, which is well below the IEEE-519 standard threshold of 5%. Moreover, the power factor reaches an outstanding 0.990, indicating highly efficient energy utilization and near-unity power factor operation. To validate the theoretical findings, a 500 W laboratory prototype was implemented using the dSPACE ds1104 digital controller. Steady-state analysis reveals sinusoidal input currents with minimal THD and a power factor approaching unity, thereby enhancing grid stability and energy efficiency. Transient response tests further demonstrate the system’s robustness against load and voltage fluctuations, maintaining output voltage stability within an 18 V overshoot and a 20 V undershoot during load changes, and achieving rapid response times as low as 0.2 s. Comparative evaluations against conventional methods underscore the superiority of the proposed control strategy in terms of both performance and implementation simplicity. By harnessing the strengths of ANFIS-based voltage regulation and predictive current control, this scheme offers a robust solution to power quality issues in AC/DC boost rectifiers, promising substantial energy savings and improved grid stability. The results affirm the potential of the proposed system to set new benchmarks in power factor correction technology.

Deadbeat Predictive Control Method for 4-leg Inverters

Until now, computational burden alleviation and stability issues for the three-phase four-leg converter has not yet been thoroughly investigated. However, compared to the conventional controllers, the implementation of predictive current control approach for 3-Ø, 4-L inverter suffers a large computational burden due to its additional fourth-leg. Motivated by this fact, this article provides an alternative predictive current control implementation for 3-Ø, 4-L inverter which offers reduced computational effort to achieve similar performance as the conventional FCS-MPC and ensures the global stability of the closed-loop system. To further understand the consequences of the developed control law, theoretical stability analysis has been carried out that links Lyapunov's direct method with the closed-loop system behavior. The outcome of the theoretical stability analysis demonstrates the global stability of the overall system which is later supported by the experimental results. With the proposed method, the number of possible voltage vectors required to obtain the optimal voltage vector in each sampling interval reduces from sixteen to five and thereby simplifies the prediction process. It is also derived that the Lyapunov function-based approach actually yields to the dead-beat control, which has not been previously highlighted in the previous papers. The current work also provides experimental results for different loading conditions (balanced and unbalanced) which further demonstrates the efficacy of the proposed method.

Fast Finite-State Predictive Current Control of Electric Drives

This work presents a novel optimization method for the implementation of finite-state model-based predictive current controllers in electrical drives. The proposal avoids the usual exhaustive search to find the control action, reducing the computational burden. The method is based on physical considerations of the power converter voltage vectors and is easy to implement on digital signal processors. The proposal is applied to a five-phase induction machine. Experimental results are compared with those obtained by a standard model-based controller, showing the feasibility of the proposal and the improvements in terms of sampling time reduction and control accuracy.

Optimized Multi-Carrier PWM Strategy and Topology Review for Multi-Cell Series-Parallel Medium-Voltage Rectifier

Solid-state transformer (SST) acting as a medium-voltage (MV) rectifier is a viable solution to supply low-voltage DC (LVDC) loads directly from the MV ac grid. Different from a classical boost-derived power-factor-correction (PFC) topology, the multicell series-parallel (MCSP) converter steps down and distributes the input ac voltage by multiple switching cells while providing the PFC function. We propose an optimized multicarrier pulsewidth modulation (PWM) strategy to avoid unwanted modes by modified multicarrier waveforms for ensuring frequent parallel connectivity to improve balancing effect while preserving simple current control implementation. Compared with conventional phase-shifted (PS) PWM and other modified multilevel carrier methods, the proposed method has no adverse effect on the input current distortion and optimizes the balancing effect on the capacitor voltages resulting suppressed circulating currents. Effectively reduced current stresses on the switch devices could lead a reduction of conduction loss on the device. Topology discussion, circulating currents, digital implementation, and loss analysis are provided. Finally, the superiority of the proposed PWM method is validated by thermal-based simulation presenting a power loss breakdown and comparing with other PWM methods. A full-scale prototype is developed, and the experimental outcomes verify the remarkable performance of proposed PWM scheme in balanced and even suppressed switch currents with improved system efficiency.

Steady-State and transient assessments of integral back-stepping current controllers in high-voltage direct current transmission systems

In the last five decades, proportional-integral (PI) controller remains dominant in control of high-power converters in industrial and utility power systems despite its bandwidth, hence, the performance is coupled to power circuit parameters and degrades in parts of operating range. Consequently, further mitigation measures such as fine-tuning or loop reshaping might be needed. In contrast, integral back-stepping (IBS) decouples controller bandwidth and performance from the system parameters; hence, leads to consistent performance throughout the operating range and simplifies tuning of controllers with complex structures with multiple loops. Therefore, this paper investigates the suitability of IBS for implementation of inner current controllers of the voltage source converter (VSC)-based high-voltage direct current (HVDC) transmission systems. The paper presents step-by-step synthesis of back-stepping current controller and supporting theoretical bases, and assesses its performance against the conventional PI current controller. Theoretical analysis and discussions and comparative simulations reveal that the characteristics of IBS technique enjoys unique characteristics: decouples the controller gains from the converter parameters; restricts closed loop poles to real axis; and exhibits larger closed loop bandwidth than the PI counterpart. It has been shown that the gains of IBS current controllers are explicitly specified in terms of the desired natural frequency and damping ratio, which are advantageous compared to that of the PI equivalent, in which the closed loop bandwidth are limited by converter parameters. For ease of illustration of similarities and differences, only inner current controllers of the converter stations were designed using integral back-stepping technique and compared against PI equivalents. The outer control loops such as dc link voltage, active and reactive power controllers are designed based on proportional-integral controllers. MATLAB-SIMULINK models of the point-to-point VSC-HVDC system, in which the current controllers implemented using integral back-stepping and proportional-integral controllers (active/reactive power and DC link voltage controllers) have been developed and subsequently used for performance comparison. Results of the one-to-one comparison show that the integral back-stepping current controller can match and even outperform its proportional-integral equivalent during normal and abnormal conditions, including current limitation during ac faults. Selected experiments conducted on grid connected voltage source converter that employs IBS current controller have confirm its viability.

Model Predictive Control based Direct Matrix Converter fed Permanent Magnet Synchronous Machine drives for Traction and Electric Mobility Applications

There have been extensive research works going on electric mobility but most of these work and the existing electric mobility systems are battery-based DC systems. In some applications of electric mobility like traction and advanced technologies like electromagnetic induction charging, AC fed systems are employed due to the innate qualities of AC power transmission. Almost all the electric mobility systems we use are AC induction or permanent magnet machines. The conventional electric mobility systems including traction having AC as their energy source use two-stage conversion i.e. A fixed AC is converted to a fixed or variable DC link using a rectifier and finally, an inverter provides a variable AC in terms of frequency and magnitude according to the control algorithm. The two-stage conversion has its pros and cons but Matrix Converter (MC) will be a suitable and efficient alternative for AC fed AC motor drives. In the case of traction and other electric mobility applications, the load torque demand plays a significant role. The predictive control technique provides a suitable solution for these kinds of special drive applications due to their selective parameter control ability. Implementation of predictive control using a matrix converter is more effective than the conventional inverter fed drives, owing to the increased viability of matrix converter switching configurations. This paper discusses the mathematical implementation and comparison of Predictive Current Control (PCC) and Predictive Torque Control (PTC) with and without weighing factor for AC fed electric mobility applications. The efficacy of both the model predictive control techniques in concern of execution time, steady-state, transient, and dynamic conditions are analysed and validated along with the influence of diverse control variables in the cost function.

A DSP‐based implementation of fuzzy logic and predictive current control for a Sheppard–Taylor power factor correction converter

AbstractEnsuring a high electric power quality of power systems and electric machinery continues to be a major challenge for power engineers. The research on harmonic reduction and improvement of power factor in connection to alternating current (AC) networks has intensified. This paper focuses on the simulation and real‐time implementation of a single‐phase Sheppard–Taylor power factor correction (PFC) rectifier. Compared to conventional PFC rectifiers, this converter provides a better network current tracking and reduces voltage stresses. Furthermore, it proves an ability to control a detuning phenomenon from which most of the PFC circuits suffer. This yields a significant enhancement in the power quality (PQ). The proposed control scheme consists of two successive controllers: (1) a fuzzy logic controller (FLC) for the voltage loop, which ensures a good robustness to changes in parameters; and (2) a predictive current control (PCC), which allows to achieve a sinusoidal network current and improves the power factor. The proposed configuration is examined by simulation and implemented in real‐time using a dSPACE DS1104 controller board. The robustness of the proposed control is tested under different loading conditions and output voltage variations. The obtained results validate the superiority of the applied approach in terms of unity power factor (0.998), THD of the network current (3.7%, approximately), and fast dynamic response.

Implementation of constant current and constant voltage charging control of a wireless charging converter

ABSTRACT In this work, implementation of constant current (CC) and constant voltage (CV) control of the LC/S compensated wireless charging converter (WCC) is presented. The LC/S compensation topology, operating as load independent in CC mode, is used in the proposed WCC. The CC charging control mode of the WCC is achieved at the constant operation frequency providing the maximum power transfer. On the other hand, frequency modulation (FM) control method is applied to achieve the CV charging control operation. Thus, implementation of entire charge period of WCC using LC/S compensation is provided with a minimum frequency variation. The basic principles and the analytical analysis of the proposed WCC are presented. The analytical output regulation, during CC and CV charging control modes, is discussed based on power transfer efficiency. Finally, a prototype with 60 W output power is built to validate the presented analytical analysis. The efficiency variations of CC and CV charging control modes are extracted as function of the load condition. The misalignment performance of the proposed system is also evaluated based on the load condition. The maximum efficiency of the proposed system is measured as 86.6% at 70 mm air gap and 40 W output power.

Design and Implementation of Four-Switch Current Sensorless Control for Three-Phase PFC Converter

Four-switch current sensorless control for three-phase four-switch converter with power factor correction (PFC) function is presented in this letter. In comparison with conventional multiloop control methods, the proposed control strategy requires sensing of two line voltages and two capacitor voltages only to achieve PFC function. As there is no sensing current, the proposed sensorless control scheme reduces the cost and complexity of design. The performance of the proposed control is validated by its implementation in digital signal processing (DSP) TMS320F28335, and the result shows that the proposed scheme is able to provide comparable PFC performance without sensing current.

Comparative Study of Discrete PI and PR Controls for Single-Phase UPS Inverter

This paper presents a comparative study of discrete proportional integral (PI) and proportional resonant (PR) current control for single-phase uninterruptible power supply (UPS) inverters. There is an increasing requirement for current and voltage-controlled UPS inverters with very low or zero steady-state error, improved transient response and lower total harmonic distortion (THD). The most promising type of current regulator for single-phase inverters is PR control because it can introduce an infinite gain at a selected resonance frequency such as the fundamental frequency to eliminate the steady-state error, which cannot be achieved by well-known proportional integral (PI) control. Note that PI control has limitations in terms of the steady-state magnitude and phase errors. In addition, PI control also has limited harmonic rejection capability, unlike the PR control, also can compensate for low-order harmonics. Imperfections in the current and voltage control scheme results in higher harmonic distortion of the output current and voltage. In this paper, performance of PR control parameters ($K_{p}$ , $K_{i}$ , and $\omega _{c}$ ) and filter parameters ($L_{f}$ and $C_{f}$ ) are optimally tuned to obtain a very low THD current with reduced output voltage ripple and steady-state error. The analysis, design and implementation of both PI and PR current control in single-phase UPS inverter applications through simulations and experiments are also presented in this paper. The performance of both of these control schemes are analyzed in terms of steady-state response, transient response, and level of current harmonics.

FPGA Implementation of Predictive Cascaded Speed and Current Control of PMSM Drives With Two-Time-Scale Optimization

This paper proposes a field programmable gate array (FPGA) implementation of predictive speed and current control of permanent magnet synchronous motor (PMSM) with two-time-scale optimization. Considering the time-scale characteristics of speed loop and current loop, different sampling times are assigned to the subsystems. The predictions of both slow and fast models consuming great computation resource for all the prediction instants are analyzed in two-time-scale system. In order to achieve a fast and accurate predictive control, the proposed method is implemented on an FPGA. Parallel unrolling and maximized parallel pipeline architecture are designed specifically to optimize the computational time of the proposed method. Experimental results validated in PMSM drives illustrate that proposed implementation achieves a high performance with balanced resource consumption.

Steady-State Error Suppression and Simplified Implementation of Direct Source Current Control for Matrix Converter With Model Predictive Control

A matrix converter (MC) with model predictive control based on the source reactive power control usually fails to show sinusoidal source currents. The analysis presented in this paper shows that this common combination of a converter and control has the inherent inability to suppress some harmonics in the source currents, even with additional passive or active damping control. Direct source current control can be implemented to give sinusoidal source currents and intrinsic active damping. However, the issue of steady-state error in output currents then arises, as the MC topology does not allow of the independent control of source and output currents. Therefore, feedback control of load active power is proposed to address this issue without degrading the fast dynamic performance. Benefiting from the direct source current control, a simplified implementation is also proposed to decrease the number of candidate switching states from 27 to 5, which significantly reduces the computational burden. Experimental results have verified the theoretical analysis and the effectiveness of the proposed control scheme.

Design and Implementation of Three-Phase Current Sensorless Control for PFC Bridge Converter With Considering Voltage Drops of Power Semiconductors

Three-phase bridge converter is popular in ac-dc power conversion. The conventional sensor control with inner current loop and outer voltage loop is often used to control the three-phase bridge converter. Many three-phase sensorless control methods had been proposed to control the bridge converter with considering the inductance and inductor resistance. In this paper, the voltage drop of the power semiconductor is first considered in the proposed three-phase current sensorless control method. At first, the dynamic behaviors of three-phase bridge converter for power factor correction (PFC) applications are studied, and its equivalent three-switch model is developed. Based on this developed model, three-phase current sensorless control with only voltage controller is proposed. Additionally, the voltage-loop transfer function of PFC bridge converter controlled by the proposed method is modeled, and the result is helpful to obtain the controller parameter. The proposed control method is implemented on the DSP-based platform for evaluation. Finally, the provided simulation and experimental results demonstrate the performance of the proposed method.

Constant voltage and constant current control implementation for electric vehicles (evs) wireless charger

This paper presents the implementation of Constant Voltage (CV) and Constant Current (CC) control for a wireless charger system. A battery charging system needs these control modes to ensure the safety of the battery and the effectiveness of the charging system. Here, the wireless charger system does not employ any post-regulator stage to control the output voltage and output current of the charger. But, it uses a variable frequency control incorporated with a conventional PI control. As a result, the size and the weight of the system are reduced. This paper discusses the brief review of the SS-WPT, control strategy and implementation of the CV and CC control. Experimental hardware with 2kW output power has been performed and tested. The results show that the proposed CV and CC control method works well with the system.

FPGA implementation and analysis of model predictive current control for three-phase voltage source inverter

A detailed investigation of the model predictive current control (MPCC) for a three-phase voltage source inverter (VSI) with an output RL filter is examined in this manuscript. The investigation on VSI and its operating conditions such as dynamic, steady state, transient state condition with balanced and unbalanced loads are explained. The parameter variations such as sampling time, filter inductance and DC-link voltage variations are also explained in terms of load current Total Harmonic Distortion (THD) and inverter switching frequency. During each sampling period, the discrete mathematical model of the system is used to predict the load current for all the inverter switching state. These predictions are estimated using cost function, and so, the switching state which gives minimum cost function is selected and applied to the inverter. The effectiveness of the control technique is verified in MATLAB software and also in real-time hardware setup using Xilinx XCS500E Spartan 3E FPGA board. The detailed simulation and hardware results are included to investigate the implementation.

FPGA implementation and analysis of model predictive current control for three-phase voltage source inverter

A detailed investigation of the model predictive current control (MPCC) for a three-phase voltage source inverter (VSI) with an output RL filter is examined in this manuscript. The investigation on VSI and its operating conditions such as dynamic, steady state, transient state condition with balanced and unbalanced loads are explained. The parameter variations such as sampling time, filter inductance and DC-link voltage variations are also explained in terms of load current Total Harmonic Distortion (THD) and inverter switching frequency. During each sampling period, the discrete mathematical model of the system is used to predict the load current for all the inverter switching state. These predictions are estimated using cost function, and so, the switching state which gives minimum cost function is selected and applied to the inverter. The effectiveness of the control technique is verified in MATLAB software and also in real-time hardware setup using Xilinx XCS500E Spartan 3E FPGA board. The detailed simulation and hardware results are included to investigate the implementation.

АНАЛІЗ ПРАВОВИХ ФОРМ ПОТОЧНОГО КОНТРОЛЮ АНТИКОНКУРЕТНИХ УЗГОДЖЕНИХ ДІЙ

The focus is on the legal forms in the implementation of the Antimonopoly Committee of Ukraine of current control in the field of violations of competition law, in particular, control over the concerted actions of business entities (cartels). Such a form of current control of the Antimonopoly Committee as consideration of cases on anti-competitive concerted actions is analyzed in detail. Special emphasis is placed on the stages and sequence of implementation of current control, which begin with the adoption of the relevant order on the commencement of proceedings on anti-competitive concerted actions. Other stages of the current control are accompanied by the adoption of interim decisions by the Antimonopoly Committee of Ukraine on procedural actions to investigate the facts of the case, to provide evidence (inspections, seizures, seizure of evidence). The current control is completed by the adoption of the Committee's decision in the case on the merits of the issue. As a result of the analysis, it was also revealed that at the legislative level, the issues concerning the procedure for exercising certain important powers of the antimonopoly body remain unresolved. This primarily concerns the legal instability in the exercise of the Committee's right to request information, the right to receive explanations, the right to withdraw evidence during inspections, and so on.

FPGA-Based Fault-Tolerant Space Vector-Hysteresis Current Control for Three-Phase Grid-Connected Converter

This paper investigates the field-programmable gate array (FPGA) implementation of a fault-tolerant space vector-hysteresis current control (SV-HCC) for three-phase grid-connected converter. The proposed control ensures continuous operation despite of an open-circuit fault in one grid current measurement circuit (caused by defected cables, lines or connectors at the output of the current measurement circuit). It is based on hardware redundancy of current measurement circuits for fault detection and isolation. The faulty measured current is identified through the computation of residuals with well-defined thresholds. Thanks to the high computation capabilities of FPGAs, the implemented fault-tolerant SV-HCC is executed with a very high sampling frequency and very low execution time. As a consequence, the defined theoretical thresholds remain available for the experimental tests. Several experimental results, carried out on FPGA-based prototyping platform, are given in order to illustrate effectiveness and reliability of the proposed fault-tolerant SV-HCC.

Identification of irregularities and allocation suggestion of relative file system permissions

It is well established that file system permissions in large, multi-user environments can be audited to identify vulnerabilities with respect to what is regarded as standard practice. For example, identifying that a user has an elevated level of access to a system directory which is unnecessary and introduces a vulnerability. Similarly, the allocation of new file system permissions can be assigned following the same standard practices. On the contrary, and less well established, is the identification of potential vulnerabilities as well as the implementation of new permissions with respect to a system's current access control implementation. Such tasks are heavily reliant on expert interpretation. For example, the assigned relationship between users and groups, directories and their parents, and the allocation of permissions on file system resources all need to be carefully considered.This paper presents the novel use of statistical analysis to establish independence and homogeneity in allocated file system permissions. This independence can be interpreted as potential anomalies in a system's implementation of access control. The paper then presents the use of instance-based learning to suggest the allocation of new permissions conforming to a system's current implementation structure. Following this, both of the presented techniques are then included in a tool for interacting with Microsoft's New Technology File System (NTFS) permissions. This involves experimental analysis on six different NTFS directory structures within different organisations. The effectiveness of the developed technique is then established through analysing the true positive and true negative values. The presented results demonstrate the potential of the proposed techniques for overcoming complexities with real-world file system administration.

Decoupled Current Model and Control of Modular Multilevel Converters

Modular multilevel converters offer several benefits, such as high scalability and power quality, which are particularly advantageous for high-voltage dc transmission systems. However, the control of such converters is very challenging due to the number of control objectives to be achieved simultaneously. The input and output currents must be controlled at their own references, and these references must be properly generated in order to keep the average capacitor voltage constant. The circulating current can be controlled either to minimize losses or to reduce capacitor voltage ripple. Additionally, the capacitor voltage must be kept balanced among cells during the converter operation. In this paper, a model with four independent dynamical components of the arm currents, which also considers the effect of ac and dc systems, is proposed. The proposed model facilitates the dynamical analysis of currents and simplifies the design and implementation of current controllers. Analysis of the proposed current model and experimental results, which confirm the performance of the designed controllers, is shown.