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Spacecraft formation flying for interferometric observations around the 2nd Lagrange point in the Sun-Earth system (SEL2) is currently focal point in deep space exploration research, which demands high precision in relative position control of spacecraft. This paper proposes the relative motion dynamics of satellite formations around the L2 point in the port-Hamiltonian framework, and establishes a high-precision nonlinear dynamics model. PID passivity-based control (PID-PBC) is widely used in engineering. However, existing methods of PID-PBC cannot address the trajectory tracking issues in port-Hamiltonian systems. Utilizing the contraction properties of the port-Hamiltonian system, this paper proposes the trajectory tracking PID-PBC (tPID-PBC) approach, effectively resolving trajectory tracking issues for formation dynamics around L2 point in port-Hamiltonian framework. The paper details explicit solutions of the Partial Differential Equations (PDE) for the tPID-PBC method and its controller structure, and references the trajectories of interferometric observation formations, to verify the method's effectiveness through numerical simulation. The presented control approach is applicable across generic port-Hamiltonian systems, offering substantial theoretical value. [ABSTRACT FROM AUTHOR]

Summary: This paper presents an adaptive nonlinear control scheme to ensure the stability of a boost converter in a DC microgrid that supplies a constant power load (CPL) and a resistive load. The proposed controller comprises a passivity‐based control (PBC) and a Nonlinear Disturbance Observer‐Based Robust Control (NDOBRC). The PBC guarantees the overall stability of the proposed controller, whereas the NDOBRC compensates for various sources of disturbances and uncertainties in the system, such as CPL power. The large‐signal stability of the PBC is established using the Lyapunov function. Simulation and experimental results demonstrate the effectiveness of the proposed controller in terms of superior performance compared to the PI method. [ABSTRACT FROM AUTHOR]

Unified force-impedance control (UFIC) aims at integrating the advantages of impedance control and force control. Compliance and exact force regulation are equally important abilities in modern robot manipulation. The developed passivity-based framework builds on the energy tank concept and is suitable for serial rigid and flexible-joint robots. Furthermore, it is able to deal either with direct force measurements or model-based contact force estimation. Thus, in this theoretical framework, the most relevant practical systems are covered and shown to be stable for arbitrary passive environments. Particular focus is also laid on a robust impedance-based contact/non-contact stabilization methodology that prevents abrupt, unwanted, and potentially dangerous movements of the manipulator in case of contact loss, a well-known problem of both impedance and force control. The validity of the approach is shown in simulation and through various experiments. Our work roots in Haddadin (2015); Schindlbeck and Haddadin (2015), where the basic UFIC regulation controller was proposed. In the present paper, we significantly advance this idea into a complete theoretical UFIC tracking framework, including rigorous stability analysis and extensive experimental evidence. [ABSTRACT FROM AUTHOR]

Quadrotor unmanned aerial vehicles (UAVs) have emerged as versatile platforms applicable to various fields such as surveillance, reconnaissance, and mapping. However, the limited energy capacity inherent in these vehicles poses a significant challenge. This limitation is a critical concern hindering their widespread adoption across diverse applications. Despite various proposed technological solutions addressing the energy consumption issue, the central challenge for the control community lies in developing controllers that ensure stability, robustness, and energy efficiency. In this paper, we present a passivity-based sliding mode controller (P-SMC) designed specifically for quadrotor UAVs. The suggested controller capitalizes on the robustness of the SMC and the energy efficiency of passivity-based control theory. Feedback passification is employed to create a sliding surface with passivity, ensuring stability. The inclusion of a noncontinuity term in the proposed P-SMC guarantees global asymptotic convergence to the sliding surface. To address the multi-faceted nature of the problem, a multi-objective optimization criterion is introduced. This criterion, which combines tracking error and control energy, is solved using the ant colony optimization (ACO) algorithm. The optimization process aims to identify control parameters that strike a balance between tracking accuracy and energy efficiency. Additionally, a conventional sliding mode method is developed to respond to conditions of attempted reach and sliding. Finally, the effectiveness of the proposed method is demonstrated through simulation results considering piecewise constant external disturbances. The outcomes based on the proposed control strategy indicate a notable reduction in energy consumption (ranging from 23% to 27%), faster reaching times (5–8 times), higher accuracy approximately (99%), and reduced chattering compared to the conventional sliding mode technique. [ABSTRACT FROM AUTHOR]

This paper addresses the problems of valve-turning operation in rescue environments where a wheeled mobile manipulator (WMM) is employed, including the possible occurrence of large internal forces. Rather than attempting to obtain the exact position of the valve, this paper presents a solution to two main problems in robotic valve-turning operations: the radial position deviation between the rotation axes of the tool and the valve handle, which may cause large radial forces, and the possible axial displacement of the valve handle as the valve turns, which may lead to large axial forces. For the former problem, we designed a compliant end-effector with a tolerance of approximately 3.5° (angle) and 9.7 mm (position), and provided a hybrid passive/active compliance method. For the latter problem, a passivity-based force tracking algorithm was employed. Combining the custom-built compliant end-effector and the passivity-based control method can significantly reduce both the radial and the axial forces. Additionally, for valves with different installation types and WMMs with different configurations, we analyzed the minimum required number of actuators for valve turning. Simulation and experimental results are presented to show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper aims to show how the switching frequency influences the properties of the digitally controlled voltage source inverter (VSI). The measurements of the Bode plots of the inverter are shown and discussed to present the existing signal delays and power conversion efficiency, depending on the switching/sampling frequency. Two types of controllers are presented, Single-Input–Single-Output (SISO) and Multi-Input–Single-Output (MISO), and adequate prediction units (the Smith Predictor for SISO—Coefficient Diagram Method and the full-state Luenberger Observer for MISO—Passivity Based Control) were used to compensate for the delays. It will be shown by comparing the THD of the VSI output voltage that prediction is useful with low VSI switching frequency (about 10 kHz) but is not important for the middle switching frequencies (about 25 kHz) or the high switching frequency (>50 kHz). This paper shows that increasing the switching frequency simplifies digital control without reasonably decreasing efficiency. The theoretical considerations, the Matlab/Simulink 2021b simulations, the final experimental laboratory verification are presented. [ABSTRACT FROM AUTHOR]

This paper presents a controller design to track speed, position, and torque trajectories for a permanent magnet synchronous motor (PMSM). This scheme is based on the interconnection and damping assignment passivity-based control (IDA-PBC) technique recently proposed to solve the tracking control problem for mechanical underactuated systems. The proposed approach regulates the dynamics of the tracking system error at the origin, assuming the realizable trajectories preserve the motor's port-controlled Hamiltonian structure. The importance of the contribution is two-fold: First, from the theoretical perspective, the trajectory tracking control problem is solved with proved stability properties, a topic that has not been deeply studied with the IDA-PBC methodology design. Second, from the practical point of view, the proposed control scheme exhibits a simple structure for practical implementation and strong robustness properties with respect to parametric uncertainties. The contribution is evaluated under both numerical and experimental environments considering a speed profile that demands the achievement of high dynamic performances. [ABSTRACT FROM AUTHOR]

This paper presents a passivity-based control (PBC) approach integrated with filtering for a supercapacitor (SC) in a semi-active hybrid energy storage system. The PBC is designed as a current controller using the reference provided by the filter to regulate the system's load current. Additionally, an external loop is employed to regulate the SC voltage to a desired value. In this external loop, a low-pass filter is included to decouple voltage and current control during instantaneous changes in load. A detailed, step-by-step description of both the PBC and the SC voltage control strategy is provided, illustrating how voltage regulation is effectively decoupled from current control to ensure optimal operation during load transients. The effectiveness of the proposed control strategy is validated through simulations and Power Hardware-in-the-Loop testing under variable current loads. This comprehensive evaluation method enables testing of control strategies in scenarios closely resembling real-world applications. [ABSTRACT FROM AUTHOR]

The LLC resonant converter is a widely used DC/DC converter that offers the benefit of enabling soft switching compared to classical DC/DC converters. However, traditional PI control strategy based on a linear model has drawbacks such as slow dynamic response and poor anti-interference performance. To overcome the shortage, a passivitybased control strategy based on the Euler–Lagrange (EL) model is proposed in this paper to improve the dynamic performance of the half-bridge LLC resonant converter. In addition, the stability of the system based on the proposed strategy is analyzed and verified. Further, the effectiveness and performance of the proposed strategy is verified in the simulation by comparing with the traditional PI controller. Finally, a prototype was built to verify the dynamic performance of the LLC resonant converter based on the proposed control strategy.

Summary: LCL‐type grid‐connected inverters have seen extensive use of the passivity‐based control (PBC) system. However, traditional PBC systems rarely take time delay into account while designing the system or doing a stability study. Therefore, utilizing Lyapunov's criterion to conclude that the system is stable is not accurate. The analysis revealed that the differential terms of PBC loops with the Euler–Lagrange (EL) mathematical model could induce instability considered control delay for LCL‐type grid‐connected inverter system. Compared with traditional EL‐PBC method, this paper proposed a reconstructed EL‐PBC scheme by properly optimizing the noise term. Then, the equivalent output impedance of the grid‐connected inverter system with proposed controller is analyzed with frequency domain passivity theory. The controller parameters are also optimized to ensure both the internal stability of LCL‐type grid‐connected inverter and the risk of interactive resonance in complex weak and nonideal grid. Results from simulation and experimentation support the modified control structure's efficacy and performance. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new passivity‐based controller design technique for discrete‐time fully actuated systems. The controller establishes finite‐time and fixed‐time convergence of dynamical system trajectories to an equilibrium state. A new form of a dissipation function, selected a priori, is introduced to design a feedback control rule to achieve such convergence properties. An energy shaping and damping injection methodology is extended to achieve non‐asymptotic stabilization. A numerical example to validate the proposed methods is provided. [ABSTRACT FROM AUTHOR]

This paper proposes an algorithm to passivity-based control (PBC) for the current control loop of the cascaded H-bridge converter (CHB) connecting the grid-connected PV system with the space vector modulation (SVM) algorithm using the law of expanding any number of voltage levels. The algorithm SVM in this paper is suitable for CHB converters. It can create a number of high levels of alternating voltage that other methods cannot do. Passivity-based control (PBC) algorithm aims to create a flexible controller that can change its structure or parameters to adapt to changes in the system, ensuring stable system quality, reducing switching losses and gaining energy conversion efficiency. It enhances the capability of accurately delivering power on demand to the grid with the CHB inverter in situations in which the grid demands the mobilization of maximum power from the photovoltaics (PV) system. The simulation results of the 9-level CHB system performed by MATLAB/Simulink software have proved the feasibility of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Inverters are important interfaces between micropower sources and consuming loads. However, the varying inductors and capacitors, modeling errors, measurement errors, and external disturbances would lead to degradation of the inverters' performances when conventional linear control is adopted, causing instability problems. To address it, a disturbance-rejection passivity-based nonlinear control strategy is proposed for the inverters of micropower sources. The proposed method innovatively introduces an extended high-gain state observer into the passivity-based controller to achieve online observation and elimination of complex influencing factors such as external disturbances, time-varying parameter uncertainties, and modeling errors, thus ensuring the global stability of the inverter under various disturbances. The design details on the passivity-based controller and the extended high-gain state observer are elaborated. The effectiveness and feasibility of the proposed control strategy are verified by the experiments performed by a 15 kVA inverter designed in the lab. The results show that the proposed control is able to ensure the inverter's stable operation under the following conditions: constant power load, the filter inductance and capacitance reduce up to 33% and 96%, and the input voltage varies more than 22%. [ABSTRACT FROM AUTHOR]

The passivity‐based boundary control is considered for stochastic Korteweg–de Vries–Burgers (SKdVB) equations. Both the stochastic input strictly passive (SISP) and stochastic output strictly passive (SOSP) are studied. By introducing Lyapunov functionals and Wirtinger's inequality, sufficient criteria are derived to establish SISP and SOSP for SKdVB equations with boundary disturbances. Moreover, when parameter uncertainties arise in SKdVB equations, the robust stochastic passivity is also investigated and sufficient criteria are presented to achieve the robust SISP and SOSP. Two numerical simulations are employed to show the effectiveness and advantages of our theoretical results. [ABSTRACT FROM AUTHOR]

Summary: The unidirectional multilevel rectifier has been used in numerous industrial applications due to its reduced active power switches, higher power density, and lower cost compared to conventional bidirectional converters. Recently, the unidirectional five‐level rectifier has been proposed for its lower device stress and the potential for extension to higher levels. However, it adopts a conventional linear proportional integral (PI) control strategy and sinusoidal pulse‐width modulation (SPWM) method, resulting in a complex control structure, particularly for the balance control of the midpoint voltage, and suboptimal dynamic performance. To address this issue and enhance system's large‐scale stability, a hybrid passivity‐based control (PBC) strategy, along with a simplified mathematical model, has been proposed. The hybrid PBC control strategy includes an outer loop active disturbance rejection (ADR)‐PI controller and inner loop PBC controller, providing a simple overall control structure and strong anti‐interference ability. Additionally, a space vector pulse‐width modulation (SVPWM) algorithm has been briefly introduced and applied to further improve the recovery and balance speed of the DC‐side capacitor voltages. Simulation and experiment results have validated the feasibility and effectiveness of the proposed hybrid PBC strategy and the SVPWM algorithm. [ABSTRACT FROM AUTHOR]

Renewable energy production through electrolysis of water to obtain "green hydrogen" has gained interest as a clean energy storage option. However, integrating variable renewable energy resources into the grid poses challenges to maintaining energy balance and stability. In this paper, a hybrid energy storage system combining short-term battery energy storage system and long-term hydrogen-based energy storage system is proposed for an isolated DC microgrid with a structure similar to a hydrogen refueling station. Passivity-Based Control (IDA-PBC) is utilized for power converters regulation, ensuring global stability based on Lyapunov theory while accounting for the nonlinear characteristics of the physical system. The control strategy is designed to ensure a reliable supply of electrical energy to the loads, preserve the quality of electrical variables in the network, and secure the safe operation of system components. Additionally, to safeguard devices from overvoltage, a Sliding Mode Reference Conditioning loop (SMRC) is proposed. It intervenes only when there is a potential risk of exceeding predefined boundaries. Simulations results under demanding conditions demonstrate the effectiveness of incorporating hydrogen energy storage systems with IDA-PBC and SMRC for this class of problems. • An isolated MG with H2 storage, typical structure of a refueling station, was modeled. • The IDA-PBC ensures the stability of the nonlinear and complex MG. • SMRC ensures overvoltage protection in the bus. • The control confirms that H2 storage integrated with RES contributes to MG stability. [ABSTRACT FROM AUTHOR]

Point‐to‐point control of underactuated mechanical systems is a challenging problem, especially if some of the system's parameters are uncertain. A popular method to stabilize underactuated manipulators is total energy shaping, in which a new Hamiltonian function is assigned to the closed‐loop system while a set of partial differential equations (PDEs) should be solved. In this study, an adaptive total energy shaping controller based on the approach called interconnection and damping assignment passivity‐based control (IDA‐PBC) for some underactuated robots is designed. The proposed method can overcome uncertainties in the dynamical parameters and also the parameters of the input mapping matrix under the satisfaction of the PDEs. The stability of the desired pose is ensured by the Lyapunov approach via suitable design of adaptation laws without the requirement for the persistence of excitation condition or other similar conditions. The results are applied to a 3‐DOF underactuated manipulator and verified by simulations. [ABSTRACT FROM AUTHOR]

Satellite formation flying technology currently represents a focal point in space mission research. Traditional spacecraft payload performance and lifespan are often constrained by propellant limitations. Electromagnetic Formation Flying (EMFF), a propellant-free formation flying technique, has garnered widespread attention. Its inherent strong nonlinearity and coupling present challenges for high-precision control within EMFF. This paper presents the relative motion dynamics of a two-satellite EMFF in the port-Hamiltonian framework and constructs an accurate nonlinear model of the dynamics. Utilizing the concept of Interconnection and Damping Assignment and nonlinear disturbance observer, a composite disturbance-rejection passivity-based controller is designed, offering a method for controlling the magnetic dipole strength of formation satellites. Finally, numerical simulations are conducted to demonstrate the viability of the proposed dynamics model and control strategy. [ABSTRACT FROM AUTHOR]

When the operating state of the power system changes, a modular multilevel converter power electronic transformer (MMC-PET) based on modular multilevel converters cannot perform efficient energy transfer and power conversion under conventional control strategies. To address the above problems, this paper proposes a passive, second-order super-helical sliding mode control strategy for MMC-PET by combining passive control and second-order super-helical sliding mode control with a stronger anti-interference capability. First, a Euler–Lagrange model based on positive and negative sequence separation is established according to the mathematical model of the MMC; second, the model of the system is passively analyzed, and a passive controller is designed according to its passivity, and the passive controller is further optimized by using the super-helical second-order sliding mode control, which improves the overall robustness and interference immunity; finally, the effectiveness and superiority of the super-twisting second-order sliding mode passive control strategy is demonstrated by verifying it through the construction of the MMC-PET simulation model and testing it under various non-ideal working conditions. [ABSTRACT FROM AUTHOR]

Today voltage source inverters (VSIs) operate with high switching frequencies (let us assume higher than 50 kHz) owing to the fast Si (Silicon) or SiC (Silicon Carbide) switching transistors. However, there are some applications, e.g., with slower switches (e.g., IGBT—Isolated Gate Bipolar Transistor) or when lower dynamic power losses are required when the switching frequency is low (let us assume about 10 kHz). The resonant frequency of the output filter is usually below 1 kHz. The measurements of Bode plots of the measurement traces of various microprocessor-controlled VSIs show that in this frequency range, the characteristics of these channels can be simply approximated through two or three switching periods delay. For the high switching frequency, it is not noticeable, but for the low frequency it can cause some oscillations in the output voltage. One of the solutions can be to use the predictor of the measured state variables based on the full-state Luenberger observer or the linear Kalman filter. Both solutions will be simulated in MATLAB/Simulink and the chosen one will be tested in the experimental VSI. The research aims to omit delays in the measurement channels for the low switching frequency by using the predictions for the measured state variables and finally increasing the gains of the controller to decrease the output voltage distortions. [ABSTRACT FROM AUTHOR]

The need for industrial and commercial machinery to maintain high torque while accurately following a variable angular speed is increasing. To meet this demand, induction motors (IMs) are commonly used with variable speed drives (VSDs) that employ a field-oriented control (FOC) scheme. Over the last thirty years, IMs have been replacing independent connection direct current motors due to their cost-effectiveness, reduced maintenance needs, and increased efficiency. However, IMs and VSDs exhibit nonlinear behavior, uncertainties, and disturbances. This paper proposes a robust combined adaptive passivity-based control (CAPBC) for this class of nonlinear systems that applies to angular rotor speed and stator current regulation inside an FOC scheme for IMs' VSDs. It uses general Lyapunov-based design energy functions and adaptive laws with σ -modification to assure robustness after combining control and monitoring variables. Lyapunov's second method and the Barbalat Lemma prove that the control and identification error tends to be zero over time. Moreover, comparative experimental results with a standard proportional–integral controller (PIC) and direct APBC show the proposed CAPBC's effectiveness and robustness under normal and changing conditions. [ABSTRACT FROM AUTHOR]

This work investigates the energy shaping control of a class of underactuated mechanical systems subject to state‐dependent linearly parameterized matched disturbances. To this end, a new integral interconnection and damping‐assignment passivity‐based design is proposed. The controller design is developed for systems subject to either momenta‐dependent disturbances or position‐dependent disturbances or to both simultaneously. The effectiveness of the proposed approach is demonstrated with numerical simulations on three examples: an Acrobot system with nonlinear friction; a ball‐on‐beam system with constant and position‐dependent disturbances; a disk‐on‐disk system with a complete set of state‐dependent disturbances. In all examples, the proposed controller shows better performance compared to previous implementations. [ABSTRACT FROM AUTHOR]

Within a robotic context, the techniques of passivity‐based control and reinforcement learning are merged with the goal of eliminating some of their reciprocal weaknesses, as well as inducing novel promising features in the resulting framework. The contribution is framed in a scenario where passivity‐based control is implemented by means of virtual energy tanks, a control technique developed to achieve closed‐loop passivity for any arbitrary control input. Albeit the latter result is heavily used, it is discussed why its practical application at its current stage remains rather limited, which makes contact with the highly debated claim that passivity‐based techniques are associated with a loss of performance. The use of reinforcement learning allows to learn a control policy that can be passivized using the energy tank architecture, combining the versatility of learning approaches and the system theoretic properties which can be inferred due to the energy tanks. Simulations show the validity of the approach, as well as novel interesting research directions in energy‐aware robotics. [ABSTRACT FROM AUTHOR]

Controlling the Permanent Magnet Synchronous Motor (PMSM) can be challenging due to the nonlinearity of its dynamics, which makes it difficult to design control strategies that are both robust and effective. To address this challenge, this paper presents a novel control strategy rooted in the concept of passivity that combines field‐oriented control (FOC). This strategy compels the PMSM to accurately follow velocity and electrical torque trajectories. The approach, known as passivity‐based control (PBC), entails reshaping the inherent system energy while introducing the necessary damping to attain the desired objectives. A crucial aspect involves identifying workless force terms within the process model. Despite their presence, these terms do not impact the energy balance and stability properties. As a result, eliminating these terms is unnecessary. This simplicity in control architecture not only preserves system stability but also bolsters overall robustness. The system's overall stability and the current tracking error's exponential convergence have both been demonstrated analytically. In order to maintain stability, the controller accounts for the nonlinearities of the plant and approximates the unstructured dynamics of the PMSM. The proposed control is designed using the dq model of the PMSM, which avoids the model's structure destruction due to singularities, since the dq model does not depend explicitly on the rotor angular position. Experimental results shown further, illustrate speed and position control with a desired pair calculated by a filter or a proportional‐integral (PI) controller for speed control and a proportional‐integral‐derivative (PID) controller for position control. Also the correlation between practical and theoretical results is given as well as the robustness test in relation to the uncertainties of the PMSM's inertia moment. The results demonstrates the effectiveness of the proposed strategy in controlling the PMSM under different operating conditions, highlighting its potential for industrial applications. [ABSTRACT FROM AUTHOR]

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In this article, we propose a model for a stand-alone hybrid distributed generation system. In this model, the input sources are distributed DC sources like solar panels or batteries. The idea behind this network framework is to introduce a hybrid DC/AC network, feasible for small and remotely located areas with stand-alone DC grids, in the vicinity of larger towns requiring a functional AC connection. The behaviour of the system in the steady state is analysed, and the network is mathematically represented with port-controlled Hamiltonian modelling. Stabilization to the desired voltage, both AC as well as DC, is attained with nonlinear passivity-based control taking into consideration not only the energy characteristics but also the inherent physical structure.

In a modern electrified aircraft, fuel cells, batteries, and supercapacitors are promising power sources to supply the onboard electric loads, such as flight control actuators, avionics, etc. These loads are mainly regulated power converters and motor drive systems, which behave as constant power loads (CPLs) that can significantly affect the system’s stability. The system may become unstable and cannot operate at rated power. This paper proposes a composite controller composed of a passivity-based controller (PBC) and an extended high-gain state observer (EHGSO) for the terminal DC–DC converters of source units of an onboard DC microgrid. The PBC can guarantee system stability in all load types, while the EHGSO can improve control performances by accurately estimating system disturbances, including unmolded dynamics and parameter uncertainties. A test-rig setup, which consists of a CPL fed by two source units through two parallel-connected bidirectional Buck-Boost converters, is developed in the lab. The effectiveness of the proposed composite controller is verified by the experimental results performed by it.

This paper presents a passivity-based control (PBC) approach integrated with filtering for a supercapacitor (SC) in a semi-active hybrid energy storage system. The PBC is designed as a current controller using the reference provided by the filter to regulate the system’s load current. Additionally, an external loop is employed to regulate the SC voltage to a desired value. In this external loop, a low-pass filter is included to decouple voltage and current control during instantaneous changes in load. A detailed, step-by-step description of both the PBC and the SC voltage control strategy is provided, illustrating how voltage regulation is effectively decoupled from current control to ensure optimal operation during load transients. The effectiveness of the proposed control strategy is validated through simulations and Power Hardware-in-the-Loop testing under variable current loads. This comprehensive evaluation method enables testing of control strategies in scenarios closely resembling real-world applications.

This paper aims to show how the switching frequency influences the properties of the digitally controlled voltage source inverter (VSI). The measurements of the Bode plots of the inverter are shown and discussed to present the existing signal delays and power conversion efficiency, depending on the switching/sampling frequency. Two types of controllers are presented, Single-Input–Single-Output (SISO) and Multi-Input–Single-Output (MISO), and adequate prediction units (the Smith Predictor for SISO—Coefficient Diagram Method and the full-state Luenberger Observer for MISO—Passivity Based Control) were used to compensate for the delays. It will be shown by comparing the THD of the VSI output voltage that prediction is useful with low VSI switching frequency (about 10 kHz) but is not important for the middle switching frequencies (about 25 kHz) or the high switching frequency (>50 kHz). This paper shows that increasing the switching frequency simplifies digital control without reasonably decreasing efficiency. The theoretical considerations, the Matlab/Simulink 2021b simulations, the final experimental laboratory verification are presented.

This paper proposes a hybrid control scheme that combines fractional-order sliding-mode control (FOSMC) with radial basis function neural network adaptive damping passivity-based control (RBFPBC) for modular multilevel converters (MMC) under non-ideal operating conditions. According to the passive control theory, we establish the Euler–Lagrange (EL) models of positive and negative sequences based on the unbalanced grid. A passivity-based controller that satisfies the energy dissipation law is designed. To enable rapid convergence of the system energy storage function, a radial basis function neural network (RBFNN) is introduced to adjust the injection damping adaptively. Additionally, a fractional-order sliding-mode controller (FOSMC) is designed. The fractional-order sliding mode surface used can improve tracking performance, and effectively suppressed the undesirable chattering phenomenon compared to the traditional sliding-mode control (SMC). Finally, combining the two control methods can effectively solve the issue of passivity-based control (PBC) being too dependent on parameters. The proposed hybrid control scheme enhances the ability of the system to resist disturbances, and improves its overall robustness. Simulation results demonstrate the feasibility and effectiveness of this control method. [ABSTRACT FROM AUTHOR]

In this paper, a two-layer hierarchical control strategy for an isolated DC microgrid with a hybrid energy storage system is considered. The DC microgrid studied is composed of a short-term battery energy storage system, long-term hydrogen-based energy storage system and renewable energy resources. The proposed control strategy, combines concepts of Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) as a primary level and Model Predictive Control (MPC) as a supervisory level. The IDA-PBC layer guarantees a correct power balance and ensures global stability according to Lyapunov theory, considering the non-linear behavior of the physical system. On the other hand, the MPC layer calculates the reference signals for the primary level, ensuring null stationary error in the desired variables. As known, it is important to keep the electrolyzer, the fuel cell and the batteries in a safe operating mode to increase their useful life and guarantee the quality of the hydrogen produced. In this sense, the benefits of MPC are exploited by considering system constraints in the controller design. The main objective of the two-layer control strategy is to ensure the supply of electrical energy to the loads and quality in the electrical variables of the network. Representative simulation results under demanding conditions verify the effectiveness of combining IDA-PBC and MPC for this class of problems. • An isolated MG with H2 storage, typical structure of a refueling station, was modeled. • The hierarchical control strategy successfully combines IDA-PBC and MPC techniques. • The IDA-PBC ensures the stability of the nonlinear and complex MG. • Supervisor MPC ensures zero stationary error and safe operating mode of the MG. • The control confirms that H2 storage integrated with RES contributes to MG stability. [ABSTRACT FROM AUTHOR]

This paper presents a comparison of the voltage and current dynamic responses for the Boost converter in three different simulation software, namely PSIM, PLECS, and MATLAB/Simulink, while using two types of nonlinear controllers. The utilized controller designs are (i) proportional-integral passivity-based control (PI-PBC) and (ii) inverse optimal control with PI action (IOC-PI). The main advantage of the PI-PBC and IOC-PI controllers is that both ensure the stable operation of the converter via Lyapunov's stability theory. In addition, in both controllers, integral action enables the elimination of non-modeled dynamics in the converter by allowing it to reach the reference with minimal stabilization times. The results showed that, despite the fact that all utilized simulation software applications had their advantages, the one with the best dynamic response for both nonlinear controls was PSIM. Moreover, it is easier to use for someone who has never worked with a simulation environment. The main objective of this research was to compare simulation software and find the most suitable environment for evaluating and implementing nonlinear control with regard to power electronic converter applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel control approach for integrated converters using Exact Tracking Error Dynamics Passive Output Feedback control and Exact Static Error Dynamics Passive Output Feedback control. By continuously injecting active distributed power systems (DPS) power sources into the utility grid and loads, the approach reduces harmonic current distortion and maintains unity for the grid's power factor. The paper compares existing control methods, such as P, PI, proportional–integral–derivative (PID), energy structuring and damping infusion and interconnection and damping assignment—passivity-based control and considers the impacts of instantaneous fluctuations in reference current elements on the AC side and oscillations in DC voltage generated by the DC-link voltage. Relevant switching state functions are designed, and if the maximum power can be fed exceeds the required power from grid-connected loads, the true, reactive, and harmonic current elements of loads are adjusted dynamically, resulting in in-phase sinewave grid currents. The performance analysis is performed using MATLAB/Simulink, and a smaller research prototype is built and discussed. [ABSTRACT FROM AUTHOR]

The LLC resonant converter is a widely used DC/DC converter that offers the benefit of enabling soft switching compared to classical DC/DC converters. However, traditional PI control strategy based on a linear model has drawbacks such as slow dynamic response and poor anti-interference performance. To overcome the shortage, a passivitybased control strategy based on the Euler-Lagrange (EL) model is proposed in this paper to improve the dynamic performance of the half-bridge LLC resonant converter. In addition, the stability of the system based on the proposed strategy is analyzed and verified. Further, the effectiveness and performance of the proposed strategy is verified in the simulation by comparing with the traditional PI controller. Finally, a prototype was built to verify the dynamic performance of the LLC resonant converter based on the proposed control strategy. [ABSTRACT FROM AUTHOR]

Soft-switching technologies can effectively solve the problem of switching losses caused by increasing switching frequency of grid-connected inverters. As a branch of soft-switching technologies, load-side resonant soft-switching is a hotspot for applications of high-frequency inverters, because it has the advantage of achieving soft-switching without using additional components. However, the traditional PI control strategy based on the linear model is prone to destabilization and non-robust dynamic performance when large signal perturbation occurs. In this paper, a novel Passivity-Based Control (PBC) method is proposed to improve the dynamic performance of load-side resonant soft-switching grid-connected inverter. Besides, the model based on the Port Controlled Hamiltonian (PCH) model of the soft switching inverter is carried out, and the passivity-based controller is designed based on the established model using the way of interconnection and damping assignmentpassivity based control (IDA-PBC). Both stable performance and dynamic performance of the load-side resonant soft-switching inverter can be improved over the whole operating range. Finally, a 750 W load-side resonant soft-switching inverter simulation model is built and the output performance is compared with the traditional PI control strategy under stable and dynamic conditions. The simulation results show that the proposed control strategy reduces the harmonic distortion rate and improves the quality of the output waveforms. [ABSTRACT FROM AUTHOR]

Abstract When the voltage fluctuation of the traction network occurs in high‐speed railways, the interharmonics in the grid‐side voltage will propagate to the traction motor, which results in the motor torque ripple of running trains. The ripple can cause abnormal vibrations of key train components and even influence train operation safety. However, the traditional proportional‐integral controller used in the inverter‐motor system has a weak anti‐interference capability when facing nonlinear disturbances. This paper proposes an improved passivity‐based control (IPBC) to suppress the impact of interharmonics on trains. First, the Euler‐Lagrange mathematical model of the traction inverter‐motor system is established. Then, the PBC for this system is designed by damping injection, ensuring the asymptotic stability of the system. Furthermore, to purposely suppress the impact of the periodic disturbance on the system, a repetitive controller is designed in parallel with the PBC to control the inverter‐motor system. Finally, through the offline simulation and HIL simulation, it has been verified that the proposed IPBC can effectively suppress the motor torque ripple and the vibrations of key train components. The control strategy proposed in this paper has a reference significance for improving the operational stability of high‐speed trains.

This research focuses on implementing a robust passivity-based nonlinear control method for bilateral/teleoperation systems. The key challenge is addressing communication pathways between the master and slave, control delays, and load disturbances, which can lead to instability and reduced transparency. To tackle these issues, the proposed controller incorporates a second-order super-twisting sliding-mode observer to counteract communication and control delays. A sliding mode assist disturbance observer compensates for load torque variations. The approach aims to ensure stability and transparency by handling time-varying delays. The system model comprises two interconnected direct-drive motors, simulating robotic configurations without a physical robot. The nonlinear controller framework simplifies the complex bilateral control problem, significantly improving stability and transparency performance. Computer simulations with step and sinusoidal inputs demonstrate the effectiveness of the approach, providing a satisfactory level of accuracy and transparency between estimated and actual slave positions, even with varying delays and load variations. The research contributes to control engineering by offering a robust method to enhance bilateral system performance, ensuring stable and transparent communication between the master and slave, particularly suitable for real-time internet-based bilateral control systems.

This work investigates the energy shaping control of a class of underactuated mechanical systems with first‐order actuator dynamics and subject to both matched and unmatched constant additive disturbances. To this end, a new nonlinear control law which includes two independent integral actions is presented. The controller design is outlined for systems with first‐order actuator dynamics, and also for systems with direct actuation. The effectiveness of the proposed approach is demonstrated with numerical simulations on an inertia wheel pendulum and on a ball‐on‐beam system, both actuated by electric DC motors and subject to constant disturbances. [ABSTRACT FROM AUTHOR]

In this paper, an adaptive technology and the interconnection and damping assignment passivity-based control method are combined to solve the stabilization problem for underactuated mechanical systems with uncertainties (including matched and unmatched). These uncertainties include unknown friction coefficients and unknown terms in kinetic energy and potential energy. A novel adaptive interconnection and damping assignment passivity-based control scheme is proposed and an adaptive stabilization controller is designed to make the closed-loop system locally stable. Verification is conducted on the ball and beam system. The locally asymptotic stability is demonstrated using the LaSalle's invariance principle and approximate linearization. The effectiveness of the proposed control law is verified through numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, a passivity-based control combined with sliding mode control for a DC-DC boost power converter is proposed. Moreover, a passivity-based control for a DC-DC boost power converter is also proposed. Using a co-ordinate transformation of state variables and control input, a DC-DC boost power converter is passive. A new plant is zero-state observable and the equilibrium point at origin of this plant is asymptotically stable. Then, a passivity-based control is applied to this plant such that the capacitor voltage is equal to the desired voltage. Additionally, the sliding mode control law is chosen such that the derivative of Lyapunov function is negative semidefinite. Finally, a passivity-based control combined with sliding mode control law is applied to this plant such that the capacitor voltage is equal to the desired voltage. The simulation results of the passivity-based control, the sliding mode control and the passivity-based control combined with sliding mode control demonstrate the effectiveness and show that the capacitor voltage is kept at the desired voltage when the desired voltage, the input voltage E and the load resistor R are changed. The results show that compared with the passivity-based control, the passivity-based control combined with sliding mode control has better performance such as shorter settling time, 8.5 ms when R changes and it has smaller steady-state error, which is indicated by the value of integral absolute error (IAE), 0.0679 when the desired voltage changes. The paper has limitations such as the assumed circuit parameters. [ABSTRACT FROM AUTHOR]

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When the voltage fluctuation of the traction network occurs in high‐speed railways, the interharmonics in the grid‐side voltage will propagate to the traction motor, which results in the motor torque ripple of running trains. The ripple can cause abnormal vibrations of key train components and even influence train operation safety. However, the traditional proportional‐integral controller used in the inverter‐motor system has a weak anti‐interference capability when facing nonlinear disturbances. This paper proposes an improved passivity‐based control (IPBC) to suppress the impact of interharmonics on trains. First, the Euler‐Lagrange mathematical model of the traction inverter‐motor system is established. Then, the PBC for this system is designed by damping injection, ensuring the asymptotic stability of the system. Furthermore, to purposely suppress the impact of the periodic disturbance on the system, a repetitive controller is designed in parallel with the PBC to control the inverter‐motor system. Finally, through the offline simulation and HIL simulation, it has been verified that the proposed IPBC can effectively suppress the motor torque ripple and the vibrations of key train components. The control strategy proposed in this paper has a reference significance for improving the operational stability of high‐speed trains. [ABSTRACT FROM AUTHOR]

In this work, we propose two cooperative passivity-based control methods for networks of mechanical systems. By cooperatively synchronizing the end-effector coordinates of the individual agents, we achieve cooperation between systems of different types. The underlying passivity property of our control approaches ensures that cooperation is stable and robust. Neither of the two approaches rely on the modeling information of neighbors, locally, which simplifies the interconnection of applicable systems and makes the approaches modular in their use. Our first approach is a generalized cooperative Interconnection-and-Damping Assignment passivity-based control (IDA-PBC) scheme for networks of fully actuated and underactuated systems. Our approach leverages the definition of end-effector coordinates in existing single-agent IDA-PBC solutions for underactuated systems to satisfy the matching conditions, independently of the cooperative control input. Accordingly, our approach integrates a large set of existing single-agent solutions and facilitates cooperative control between these and fully actuated systems. Our second approach proposes agent outputs composed of their end-effector coordinates and velocities to guarantee cooperative stability for networks of fully actuated systems in the presence of communication delays. We validate both approaches in simulation and experiments. [ABSTRACT FROM AUTHOR]

This article proposes two novel passivity‐based control design frameworks for hybrid nonlinear dynamical systems involving an interacting mixture of continuous‐time and discrete‐time dynamics whose dynamical properties evolve periodically over time. By deriving the Kalman–Yakubovich–Popov (KYP) conditions characterizing dissipativeness for hybrid nonlinear time‐dependent dynamical systems, a hybrid computational algorithm, which alternates between continuous‐time and discrete‐time subsystems at an appropriate sequence of time instants, is then proposed to solve the resultant equations in an interacting manner. Two passivity‐based control schemes are then developed by utilizing the foregoing KYP conditions in tandem with the passivity theorem. The overall framework consists mainly of three steps. The hybrid output dynamics of the plant are first determined judiciously to satisfy the passivity specifications. A hybrid nonlinear controller is then designed to meet the input strict passivity requirements. The stability of the closed‐loop system is finally established by interconnecting the plant and the controller through negative feedback. Practical considerations for appropriately implementing the derived hybrid algorithms are then discussed in detail. The efficacy of the proposed control schemes is ultimately assessed via a multi‐dimensional system with a hybrid source of actuation. [ABSTRACT FROM AUTHOR]

The current paper considers discrete stochastic inertial neural networks (SINNs) with reaction diffusions. Firstly, we give the difference form of SINNs with reaction diffusions. Secondly, stochastic synchronization and passivity-based control frames of discrete time and space SINNs are newly formulated. Thirdly, by designing a boundary controller and constructing a Lyapunov-Krasovskii functional, we address decision theorems for stochastic synchronization and passivity-based control for the aforementioned discrete SINNs. Finally, to illustrate our main results, a numerical illustration is provided. [ABSTRACT FROM AUTHOR]

Controlling the dynamics of chaotic systems is a task which is often addressed in an empirical way, particularly for placing sensors and actuators. Here, we show that selecting the measured variable and placing the actuator can be guided by considering the observability and controllability symbolic coefficients and applying the notion of flatness. This approach is here demonstrated on the piecewise linear Chua circuit, whose specific features are leveraged in constructing a discretized controller with a switch mechanism and optimally placed sensor and actuator. The feedback linearization is compared to a homogeneous and a passivity-based control laws, the flat control laws being more efficient than the others. It is thus shown that the proposed flat control law by feedback linearization is very efficient. The continuous time and discretized Chua circuit, governed by differential and difference equations, respectively, are treated. Most likely, these results could be extendable to a large group of natural and experimental systems. [ABSTRACT FROM AUTHOR]

Summary: In this article, we consider the problem of voltage regulation of a proton exchange membrane fuel cell connected to an uncertain load through a boost converter. We show that, in spite of the inherent nonlinearities in the current‐voltage behavior of the fuel cell, the voltage of a fuel cell/boost converter system can be regulated with a simple proportional‐integral (PI) action designed following the passivity‐based control approach. The system under consideration consists of a DC–DC converter interfacing a fuel cell with a resistive load. We show that the output voltage of the converter converges to its desired constant value for all the systems initial conditions—with convergence ensured for all positive values of the PI gains. This latter feature facilitates the, usually difficult, task of tuning the gains of the PI. An immersion and invariance parameter estimator is afterward proposed which allows the operation of the PI passivity‐based control when the load is unknown, maintaining the output voltage at the desired level. The stable operation of the overall system is proved and the approach is validated with extensive numerical simulations considering real‐life scenarios, where robust behavior in spite of load variations and the presence of noise is obtained. [ABSTRACT FROM AUTHOR]