Control Of Power Converters Research Articles

Dual Control Strategy for Non-Minimum Phase Behavior Mitigation in DC-DC Boost Converters Using Finite Control Set Model Predictive Control and Proportional–Integral Controllers

Model Predictive Control (MPC) has emerged as a promising alternative for controlling power converters, offering benefits such as flexibility, simplicity, and rapid control response, particularly when short-horizon algorithms are employed. This paper introduces a system using a short-horizon Finite Control Set MPC (FCS-MPC) strategy to specifically address the challenge of non-minimum phase behavior in boost converters. The non-minimum phase issue, which complicates the control process by introducing an initial inverse response, is effectively mitigated by the proposed method. A Proportional–Integral (PI) controller is integrated to dynamically adjust the reference current based on the output voltage error, thereby enhancing overall system stability and performance. Unlike conventional PI-MPC methods, where the PI controller has an influence on the system dynamics, the PI controller in this approach is solely used for tuning the reference current needed for the FCS-MPC controller. The PI controller addresses small deviations in output voltage, primarily due to model prediction inaccuracies, ensuring steady-state accuracy, while the FCS-MPC handles fast dynamic responses to adapt the controller’s behavior based on load conditions. This dual control strategy effectively balances the need for precise voltage regulation and rapid adaptation to varying load conditions. The proposed method’s effectiveness is validated through a multi-stage simulation test, demonstrating significant improvements in response time and stability compared to traditional control methods. Hardware-in-the-loop testing further confirms the system’s robustness and potential for real-time applications in power electronics.

Finite Control Set Model Predictive Control for Grid-Connected Parallel Power Converters With Guaranteed Optimality

Finite Control Set Model Predictive Control for Grid-Connected Parallel Power Converters With Guaranteed Optimality

Analytical Co-Design of Receding Horizon Estimation and Control for Power Converters

Analytical Co-Design of Receding Horizon Estimation and Control for Power Converters

A Multivariable, Adaptive, Robust, Primary Control Enforcing Predetermined Dynamics of Interest in Islanded Microgrids Based on Grid-Forming Inverter-Based Resources

This paper proposes a multivariable, adaptive, robust (MAR) control strategy for islanded inverter-based resources (IBRs) operating as grid-forming inverters. The proposed method is employed in the inner control loop of the primary layer in the hierarchical or decentralized structures for the islanded operation of microgrids. The MAR control scheme is responsible for stabilizing IBRs’ output voltage in autonomous operations of microgrids, considering mismatched input voltage disturbances from the grid side and a large amount of system uncertainty. The control methodology introduced in this paper does not rely on the system’s physical parameters, such as microgrid topology, load dynamics, LCL filters, and output connectors. As a result, there is no need to know the nominal values or the bounds of uncertainties in system dynamics. The MAR control method uses online adaptation rules first to identify and then adjust the control parameters of the closed-loop system based on an arbitrary dynamic model. In other words, the MAR method replaces the actual dynamics of IBRs with predetermined dynamics of interest. Simulation results in the MATLAB/Simulink environment confirm the capability of the scheme introduced for the closed-loop stabilization and voltage regulation in the presence of disturbances and a significant amount of uncertainty under various case studies; moreover, comparative simulations by comparing the presented method with other studies using sliding mode control are provided. Finally, experiments verify the effectiveness and practicality of the proposed MAR control scheme. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —Inverter-based resources are integral parts of current and especially future power and energy systems; with increasing concerns about carbon footprints, the tendency to substitute traditional synchronous generators with inverter-based resources increases. This transition towards the widespread use of power electronics devices needs careful studies regarding the stability and control of power converters. Although existing studies are addressing potential control system challenges, they suffer from complex mathematical computations and the need for the system’s preliminary information. With this in mind, this study proposes a multivariable, adaptive, robust control strategy for the inner voltage control loop of grid-forming inverters. This method utilizes online estimation algorithms to identify inverter-based resources’ parameters and tune control system parameters simultaneously, making it applicable even to cases with slow parameter variations caused by aging or environmental changes. It can compensate for potential voltage disturbances from the grid side and enable the designer to replace undesirable dynamics of inverter-based resource units with arbitrary and stable dynamics of interest. In fact, unlike traditional methods that need control parameters and gains to be tuned to achieve a proper dynamic response, the control system designer can choose reference dynamics and enforce the closed-loop system to imitate the dynamical model selected. This model is usually chosen based on established priorities, such as response time and other transient behaviors. Moreover, this method does not require complex mathematical and algebraic calculations to design and implement. It can be easily applied to inverter-based resource units after selecting the desired reference dynamics, as shown through this study’s experimental result. The above points give this method a competitive edge over the existing algorithms, especially in practical applications.

Power converters analyzed in energy storage systems to enhance the performance of the smart grid application

This paper implements and compares the existing power supply converters for an energy storage system to determine the best suited for the smart grid application. A survey of different DC-DC converters is carried out to analyze the battery's overall performance. The main objective is to identify this application's most appropriate energy storage device. The advantages of this technology have high efficiency and reliability, which can connect various energy sources and reduce conduction losses in the power converters. Through the converter control, reference currents are imposed to charge the battery. The battery nominal voltage needs to change to see which type of converter is the most suitable and robust. Simulation results show that the operating ranges of boost-buck, buck-boost, and buck-boost converters with negative output voltage enhance the efficiency of battery and renewable energy sources and compared the DC converters to know the functional voltage for the energy storage system. The power converter's efficiency and control facility will allow us to link the energy storage system with the power grid. The overall installation is established using MATLAB/Simulink software.

Small‐signal rotor angle stability of multi‐virtual synchronous machine (n‐VISMA) microgrid

AbstractAutonomous microgrid is known to lack appropriate inertia and damping for grid stabilization. Due to this, virtual synchronous machine (VISMA) has been introduced to provide necessary ancillary services through control of power converters. In a multi‐VISMA (n‐VISMA) microgrid, relative rotor angle stability of the power system is dependent on the active power balance after small perturbation. Thus, the use of relevant analytical models are essential issues for microgrid stability analysis. This paper presents a comprehensive small‐signal stability analysis to study inherent electromechanical oscillations in the virtual rotors. The subsystems of the microgrid consisting of VISMA, network, load and the outer power control were all modelled in Synchronous Reference Frame. The small‐signal model (SSM) was tested on IEEE‐9 bus system with VISMA replacing electromechanical synchronous machines on the network. To validate the developed numerical analytics, dynamic responses of the SSM are compared with those of the non‐linear (NL) system dynamics and the results reveal that the developed linearized SSM is sufficient to accurately characterize behaviour of the VISMA microgrid when operated in autonomous mode. Eigenvalues analysis and parameter sensitivities of the critical modes were investigated. Oscillatory participations of the VISMAs and steady state stability limit of the microgrid have also been investigated.

Experimental platform for studying energy regeneration in electric vehicle powertrains

Investigation into the energy consumption in electric vehicles (EVs) plays a pivotal role in determining their autonomy and assessing the electric system performance across diverse operational scenarios. This study focuses on the concept of energy regeneration, encompassing the recovery and storage of kinetic mechanical energy during braking or descent in EVs. Employing control systems in power electronics becomes necessary to establish a seamless workflow across operational quadrants to ensure efficient energy regeneration in an electric machine functioning as both a motor and a generator. To seamlessly integrate new technologies into practical applications, it is essential to conduct thorough evaluations in laboratories prior to deployment. This paper introduces an experimental platform specifically designed to analyze energy consumption and storage in EVs by emulating their powertrains in a controlled laboratory environment. The platform comprises key components for emulating the powertrain of a single-motor electric vehicle with single-axle traction, including a power converter configured in two quadrants, an energy storage system, a primary rotating electric machine, and a mechanically coupled point load torque (another motor). This paper provides a detailed guide on implementing such a laboratory and for facilitating the testing of diverse motor technologies and controllers under varied operational conditions. This comprehensive approach allows for the assessment of electromechanical system efficiency, focusing on both energy recovery and comprehensive control of electric power converters. Validation tests conducted under urban conditions and on steep terrains demonstrate the effectiveness of the platform in analyzing the energy efficiency of both the induction machine and the power controller.

Control of Power Converters in Micro Grids

Owing to several operational drawbacks in the existing power management schemes for interlinked AC-DC micro grids which are either concerned about only on sharing power or regulation of voltage but not on both, so as to overcome these issues this paper is proposed. This proposed autonomous power management scheme will consider the specific loading condition of the DC micro grid before importing power from the interlinked AC microgrid. This strategy not only enables voltage regulation in the DC micro grid but also reduces the number of converters in operation which will in turn reduces the power transfer losses. Theproposed scheme is fully self governed as it holds on the plug-nplay features for generators and tie-converters. The performance of the proposed control scheme has been validated under different operating scenarios. The results reveal the usefulness of the proposed scheme in managing the shortcoming of power in the DC microgrid efficiently and autonomously, on the other hand maintaining the better voltage regulation in the DC micro grid. In this project a DG interfacing network and its control also to be simulated to analyze the system stability The results are verified through MATLAB/SIMULINK environment.

Control of Power Converters for Soft Open Points Based on a Hybrid Approach

Control of Power Converters for Soft Open Points Based on a Hybrid Approach

Slip modes modeling of electric vehicle asynchronous electric drive

Purpose. Creation a computer model of electric drive of an electric vehicle with the possibility of modeling in slippage modes, as well as the subsequent determination of slippage detection method as early as possible to further reducing or preventing slippage. Methodology. Mathematical analysis and modeling. Findings. Mathematical models in the structural form of the control system, power converter and motor are added in a simplified way, as the blocks. For compiling a computer model, the blocks of the control system and the power converter will be assembled using models of elements of power electric circuits. The model allows the ED simulation with a huge number of parameters varying – modeling slipping processes with one or two wheels, a sharp change in engine parameters, failure of one of the components of the power circuit, etc. Using the Simulink and SimPower packages of the Matlab software package, as well as the block diagram of the electric drive, a computer model of the ED was synthesized. Computer simulation of dynamic processes in the electric drive during a collision, as well as pulling away on the road surface with a reduced coefficient of friction, was carried out. The obtained diagrams fully correspond to the real physical processes occurring in the electric vehicle and give reason to believe that the constructed mathematical and computer models are adequate. Proceeding from this, electromechanical transients in the electric drive during acceleration with slipping and one wheel runover a road surface with reduced traction were obtained and analyzed. As a result of this analysis, the most optimal and reliable way to determine the skidding mode for its further elimination was determined. Originality. Computer model of the asynchronous electric drive of an electric vehicle with a detailed mechanical part, taking into account the mechanical differential gear, was built. The model allows the ED simulation with a huge number of parameters varying – modeling slipping processes with one or two wheels, a sharp change in engine parameters, failure of one of the components of the power circuit, etc. Practical value. Computer simulation was carried out for two modes: start of electric vehicle movement , when one of the wheels has been of on the road surface with a reduced coefficient of adhesion (0,1) since launch and acceleration with a collision with a surface with a reduced coefficient of adhesion (0,1) with one wheel at the moment of time of 6.3 s.

FEATURES OF THE CONFIGURATION OF CONTROL SYSTEMS FOR PHOTOVOLTAIC INVERTERS

Today, the issue of energy supply and the implementation of ecological systems of electricity generation is relevant, including in the agricultural sector of the economy. This issue is important not only at the state level, but also at the level of the world community. The world's leading countries are actively implementing world-leading technologies for the decarbonization of the energy sector. One of the options for the introduction of alternative and renewable energy sources in the agricultural sector of the economy of the leading countries of the world is the use of photovoltaic systems. The use of modern sources of electrical energy is also inherent in the transport industry. One of the options for such implementation is the use of photovoltaic systems in electrical networks of electric transport and auxiliary systems and infrastructure complexes. Also, attention should be paid to modern global trends in the development of distributed energy systems, which are characterized to a large extent by the use of new progressive developments in power electronics. Also, attention should be paid to modern world trends in the development of distributed energy systems, which are characterized by the use of new progressive developments in power electronics, which are already used in various areas of the economy [1]. Therefore, network converters of electrical energy, which are operated as part of distributed generation systems and as part of complexes based on renewable sources of electrical energy, must meet the parameters of the network, and their control system must be adaptive to stochastic modes of network operation and modes of generation by renewable sources of electric energy. Meanwhile, attention should be paid to the synchronization of three-phase electrical energy converters with the electrical network to which they are connected, which must be ensured by a system for regulating their operation. It should be noted that the structures of control systems of network converters have a significant difference from the structures of control systems of autonomous converters, which directly concerns inverters. This state of affairs is connected with the peculiarity of the functioning of network inverters. Since the specified converters have a modulated sinusoidal voltage using PWM to form in accordance with the parameters of the network to which they are connected. Therefore, the issue of synthesizing a mathematical method that will simplify the development of an automatic control system and also optimize the computing resources of the power converter control controller for photovoltaic systems is relevant. On the basis of analytical data, it is possible to predict with full confidence the post-war development of Ukraine's economy based on the introduction of modern progressive technologies in the field of energy. To date, the sustainable development of the economic and energy component of Ukraine's economy is postponed. Meanwhile, electric power generation systems remain a priority in the context of not only implementation into existing power supply systems, but also relevant in the context of national energy security. The paper considers the use of Park's transformation in the development of control systems for network inverters of photovoltaic systems. The results of the research, which were conducted on inverters whose control systems were built using the proposed mathematical apparatus, confirm high control accuracy and efficiency, without spending a large amount of computing resources of the microcontroller. The proposed approach to building control systems for inverters of photovoltaic systems will allow to increase the efficiency of the operation of photovoltaic systems, which will make them more economically attractive for implementation in the agricultural sector of the economy.

Robust Predictive Control of Grid-Connected Converters: Sensor Noise Suppression With Parallel-Cascade Extended State Observer

Model predictive control (MPC) is a constrained optimization control method with superior performance than linear methods for multi-variable and multi-objective control of power converters. Nonetheless, its performance is limited by model uncertainties and measurement noise. This study tackles this challenge by proposing a new hybrid parallel-cascade extended state observer (PC-ESO) with two key advantages, viz.: (i) higher disturbance rejection than the conventional linear ESO and cascade ESO (CESO) at low bandwidth, and (ii) better noise suppression than the conventional ESO. PC-ESO's time-domain structure, and comprehensive frequency-domain analysis are presented. Furthermore, PC-ESO is applied to improve the transient disturbance rejection of CESO through a novel structurally-adaptive ESO (SAESO) algorithm. The proposed SAESO provides both high-frequency noise-suppression and better disturbance rejection than CESO and cascade-parallel ESO. Finally, the proposed methods are experimentally validated by the model-free predictive control of a grid-connected power converter.

A Comparative performance evaluation of a complex-order PI controller for DC–DC converters

Switched-mode DC–DC converters are required to maintain constant output under uncertainties and variations in input voltage and load. The controller’s robustness is crucial in such systems, and hence various controllers have been proposed in the past few decades for DC–DC converter control. Fractional order PID controllers have attracted the attention of researchers due to their robustness and flexibility in control of power converters. Such controllers use fractional orders of integration and differentiation. Complex order controllers are the generalized form of the fractional order PID controllers and have complex orders of integration and differentiation. These controllers are very robust in the control of nonlinear systems with time-varying parameters. But complex order controllers have been very sparingly used in power electronic control. This paper proposes a complex order PI controller with a complex order integrator for controlling DC–DC buck and boost converters. The complex PID controller has four parameters to be tuned. The complex order PI controller is designed by optimization using the metaheuristic Cohort Intelligence algorithm. The results are compared with that of a fractional-order PID controller. It was observed that the complex PI controller gave a better response than the FOPID controller and was more robust to parameter variations.

Simulation and FPGA based Implementation of PI and Fuzzy Controllers for Cascaded Asymmetric Multilevel Inverter

The main objective of this work is to improve the performance of Multilevel Inverter by using the novel LS-PD- PWM and controlling technique instead of the existing approach. The proposed work focus on closed loop controller such as existing PI and Fuzzy Logic Controller for resistive load with Multilevel Inverter. The proposed Asymmetric fifteen level Inverter offers less THD and high frequency than the Asymmetric nine level inverter. Asymmetric multilevel inverter is used to reduce the switching losses and THD. In this work is the generation and implementation of Pulse Width Modulation (PWM) techniques using Field Programmable Gate Array (FPGA) for Multilevel Inverter. PWM can be generated via Microprocessors, Microcontroller, FPGA and DSP Processors. Higher density Programmable Logic Devices (PLD) such as FPGAs can be used to amalgamate large amounts of logic into a single Integrated. Pulse width modulation (PWM) is generally used in power converter control. To generate LS-PD- PWM by using FPGA, this occupies less memory capacity and accurate than conventional one. An efficient PWM generation technique is performed using FPGA for lower frequency applications. Simulation and synthesis is done by ModelSim6.3c and Xilinx10.1. Further, the Implementation is carried out by FPGA Spartan3 Xc3s50. Key Word: PWM, FPGA, PLD (Programmable Logic Devices), LS-PD-PWM

Long-Horizon Direct Model Predictive Control for Power Converters With State Constraints

Long-Horizon Direct Model Predictive Control for Power Converters With State Constraints

Control of an Active Filter Based Three-Level Grid Connected Converter for Wind Turbine Applications

This paper presents a control design and implementation analysis of a three level grid connected converter to be deployed in large scale wind turbine applications, which main purpose is to obtain enhanced grid interaction by limiting its harmonic injection capability. The implementation of advanced power converter control in high power converters allows the proposed wind turbine system to provide active and reactive power supply while performing active filter functionalities for the 5th and 7th harmonic current components. Finally, the performance of the system is verified under several practical study cases by performing a laboratory analysis of the obtained results.

Taxonomy of Power Converter Control Schemes Based on the Complex Frequency Concept

This paper proposes a taxonomy of power converter control schemes based on the recently proposed concept of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">complex frequency</i> . This quantity captures local frequency variations due to the change of both the phase angle and amplitude of bus voltages and current injections. The paper derives the analytical expressions of the link between complex power variations and complex frequency of each converter controller as well as the identification of critical control parameters. The main contribution of this work is to provide a general framework that allows classifying converters synchronization mechanisms and controllers. This framework also allows comparing converters with synchronous machines. To validate the theoretical results, extensive simulations are performed using a modified version of the WSCC 9-bus system. Examples of how the theoretical formulations of the paper can be used to improve power converter control in power system applications are showcased.

Reliability and Lifetime Optimal Control for Electric Vehicle Power Converters

Reliability and Lifetime Optimal Control for Electric Vehicle Power Converters

Closed-Loop Current Control of a SiC-Based Power Converter via Galvanically Isolated Electroluminescence Sensing

Closed-Loop Current Control of a SiC-Based Power Converter via Galvanically Isolated Electroluminescence Sensing

Multirate Modeling and Predictive Control for WBG-Device-Based High-Switching-Frequency Power Converters

With the growth of wide bandgap devices, it is necessary to exploit the high switching frequency benefits to improve the power converter's performance, thus requiring a higher sampling/interrupt frequency in digital signal processors. However, such a short interrupt time duration imposes big computational difficulty in the execution of programming code, especially using the model predictive control (MPC). Thus, most of the existing MPCs are applied with switching frequencies below 20 kilohertz, which cannot exploit the full potential of the wide bandgap device-based power converters. To solve this challenge, this article proposes a multi-rate MPC scheme, where the trigger of interrupt and switching device transition can be performed at different rates. Compared to conventional MPCs, the main uniqueness of the proposed multi-rate MPC is that the high-dimension control sequence is solved and applied within each interrupt interval. Therefore, the increased switching frequency objective can be easily achieved with a low sampling/interrupt frequency configuration, which also significantly relieves the digital execution of the heavy interrupt tasks. The proposed method shows a more optimized control input and higher computational efficiency over the multi-rate finite-control-set MPC counterpart. A silicon carbide inverter-fed AC motor drive system is used to verify the proposed multi-rate MPC. The results show the improved system performance with the combined advantages of both the high switching frequency and MPC strategy.