Passivity-based Control Research Articles

Passivity-based controller for charging of Lithium-ion battery model 18650

This article deals with a lithium-ion battery charger using a passivity-based controller (called: the exact tracking error dynamics passive output feedback (ETEDPOFC)), which uses the constant-current constant-voltage (CC-CV) protocol. For this, the charger system consists of 3 phases. The first phase involves designing the dc-dc buck power converter, considering the operating voltage and maximum current the battery can withstand—where the passivity-based control operates in the balance points proposed as a function of the load protocols. The second phase consists of the general PSIM simulation of the system (converter + battery), which uses the Shepherd model to characterize the battery used in the tests. Finally, the third phase shows the implementation based on the system’s TMS320F28335 card DSP, just like the experimental results.

Operation Strategy for Photovoltaic Inverters with Microgrid Support Commuting from Grid-Feeding to Grid-Forming

This work proposes an operation strategy for a single-phase photovoltaic inverter to have the capability to change its operation mode from a feeding to a forming converter within an electrical microgrid. In addition, the proposed system provides AC mains support functions through reactive power injection during fault conditions. The IEEE 1547-2018 standard is taken as a basis, which considers the need to provide support in the event of low/high voltage variations, outside the normal operating limits. To meet some of the control objectives, a passivity-based control (PBC) is used. In order to validate the operating conditions and AC mains support functions some simulations are carried out.

Passivity-Based Control of Angular Velocity of PMSM with Position and Stator Currents Measurement

A novel control strategy for the angular velocity of the permanent magnet synchronous motor (PMSM) is presented. The control law is designed using current and position measurements only. The desired velocity signal is obtained through a linear second-order filter. Additionally, a formal stability analysis of the closed-loop system comprised of the motor dynamics and the second-order filter is also presented.

Sensitivity Analysis of Krasovskii Passivity-Based Controllers

In the domain of passivity theory, there were major contributions in the last decade, the most recent notion of passivity being the so-called Krasovskii passivity. This framework offers the possibility of designing a controller which ensures the passivity of the resulting closed-loop system. The current paper proposes a solution to design the parameters of Krasovskii passivity-based controllers (K-PBCs) in order to ensure small sensitivity of the closed-loop systems. As such, after the initial construction of the passivity output, the controller parameters are designed in order to impose the dominant eigenvalues of the Jacobian of the resulting closed-loop system with the smallest deviation around the given forced equilibrium point which is, additionally, smaller than a prescribed stability margin. The resulting optimization problem is non-convex by nature, and a metaheuristic approach is proposed to design these parameters. Moreover, in order to impose an extra set of performances, the control system contains an outer loop where dynamical path planning is used to impose the additional requirements. All mentioned results are developed for processes modeled as bilinear systems. In order to illustrate the proposed control method, a numerical example consisting of a single-ended primary inductor DC-DC converter (SEPIC) process is presented.

Passive robust control for uncertain Hamiltonian systems by using operator theory

In this study, the passivity-based robust control and tracking for Hamiltonian systems with unknown perturbations by using the operator-based robust right coprime factorisation method is concerned. For the system with unknown perturbations, a design scheme is proposed to guarantee the uncertain non-linear systems to be robustly stable while the equivalent non-linear systems is passive, meanwhile the asymptotic tracking property of the plant output is discussed. Moreover, the design scheme can be also used into the general Hamiltonian systems while the simulation is used to further demonstrate the effectiveness of the proposed method.

Hybrid passivity-based control for stability and robustness enhancement in DC microgrids with constant power loads

Hybrid passivity-based control for stability and robustness enhancement in DC microgrids with constant power loads

An optimized parameter design of passivity-based controller for single-phase voltage source inverters

With the advantages of fast response, good stability, and strong robustness to filter parameter variations as well as load perturbations, the application of passivity-based control (PBC) in the single-phase voltage source inverter (SPVSI) has received extensive attention. However, as a non-linear control strategy, PBC control has a complex coupling structure containing feed-forward, negative feedback, etc., which poses many difficulties for multi-damping design. In addition, ensuring the passivity of the islanded system under various load conditions or filter parameter drift is still an unresolved issue in the damping coefficient design of the PBC controller. Therefore, for SPVSI systems with LC filters, this paper proposes a multi-damping coefficient design method for PBC controllers based on stability domain analysis. The designed PBC controller can ensure system stability under several load conditions or certain deviations of LC filter parameters. Moreover, the design order from the inner to the outer control loop is adopted according to the distribution of individual damping coefficients in the control loop. As a result, each control loop has a good dynamic performance and distinct control bandwidth. Finally, robustness analysis, simulation, and experimental results verify the correctness and effectiveness of the proposed multi-damping coefficients design method for the PBC controller.

A new regulation control method for underactuated 3D overhead cranes

Interconnection and damping assignment passivity-based control (IDA-PBC) has been successfully applied to many mechanical, electrical, and electromechanical systems. For the control of such systems, existing IDA-PBC methods have concentrated on systems with underactuation degree one, such as the ball and beam system, the vertical takeoff and landing aircraft, and the pendulum on a cart. In this paper, we focus on the application of the IDA-PBC methodology to the regulation control of a three-dimensional (3D) overhead crane system with underactuation degree two. The goal of this study is to design and analyze a regulation controller that can drive the cart to the desired position precisely and eliminate the payload swing effectively. To achieve this challenging objective, we first find an ingenious way to solve partial differential equations for constructing a Lyapunov function candidate. Then, we devise a nonlinear controller on the basis of the constructed Lyapunov function and analyze the stability of the closed-loop system by using Lyapunov techniques and LaSalle’s invariance principle. Finally, both simulation and experimental results demonstrate the proposed strategy can achieve excellent positioning accuracy and significant swing elimination, and a comparison study between the proposed method and the existing PBC method is included as well.

Sensorless passivity based control of doubly-fed induction generators in variable-speed wind turbine systems based on high gain observer

The current study presents a robust sensorless control using passivity based control (PBC) combined with high gain observer (HGO). The proposed controller is applied to control the generated doubly-fed induction generator (DFIG) active and reactive power installed on a variable speed wind energy conversion system. The control objective is used to regulate independently the DFIG stator active and reactive power, which are decoupled by using the field oriented control technique. Additionally, this process leads to reduce the cost of control scheme by eliminating the speed sensor. Firstly, the DFIG is modeled under the port controlled Hamiltonian (PCH) model, as well as the method of simultaneous injection damping. Then, the DFIG is further modeled by assignment passivity based on the simultaneous injection damping and assignment (SIDA-PBC) control of the obtained model under such conditions and a comparison with the fuzzy sliding mode controller is carried out. Furthermore, the HGO is selected in order to estimate the rotor position and the speed from the measurement of the DFIG currents and voltages, and compared with fuzzy sliding mode observer. For testing the proposed control scheme performance, a 1.5 MW DFIG system is developed and simulated using MATLAB/Simulink. The obtained results demonstrate the effectiveness of the proposed control scheme in the presence of various DFIG parameters variation. Additionally, the control objective is achieved without speed sensor.

Passivity-Based Control of Dual Active Bridge Converter in Constant Power Load Condition

This paper presents a passivity-based control (PBC) based on the Euler–Lagrange (EL) model for dual active bridge (DAB) converters in the constant power load (CPL) condition. The EL model, which is derived from Kirchhoff’s current equations at the input and output nodes, is first presented in the DAB application, and the bidirectional CPL is considered in the theoretical analysis, simulation, and physical verification. The PBC has strong robustness to large-signal disturbance and negative incremental resistance load, and it is suitable for DAB converters in the CPL condition. In this paper, the DAB’s EL model, passivity analysis, stability analysis, and controller design are described in detail. The simulation results based on SIMULINK are also given in this paper. Finally, a DAB converter prototype is built to demonstrate the validity and feasibility of the proposed approach.

DC Shipboard Microgrids With Constant Power Loads: A Review of Advanced Nonlinear Control Strategies and Stabilization Techniques

In modern dc shipboard microgrid (SMG) systems, the propulsion motors and hotel loads are always supplied through tightly regulated point of load converters, which behave as constant power loads (CPLs). The negative incremental impedance due to CPL’s characteristics destabilizes the dc bus voltage of dc SMGs. Due to uncertain operating conditions of maritime ships on the sea, the dc bus voltage robust control is a crucial matter. Therefore, this paper presents a cutting-edge systematic review on advanced nonlinear control strategies to stabilize and control the CPLs in dc SMGs, such as sliding mode control, synergetic control, backstepping control, model predictive control, and passivity-based control. The latest stabilization techniques and the future trends towards an adaptive nonlinear control have been presented throughout this review. Several feedforward control-based observation and estimation techniques have been highlighted. The stability analysis and stability challenges of dc SMGs are also discussed.

Composite passivity-based control of DC/DC boost converters with constant power loads in DC Microgrids

Composite passivity-based control of DC/DC boost converters with constant power loads in DC Microgrids

Passivity-based boundary control for stochastic delay reaction–diffusion systems

This paper considers the passivity-based boundary control for stochastic delay reaction–diffusion systems (SDRDSs) with boundary input–output. Delay-dependent sufficient conditions are obtained in the sense of expectation for SDRDSs by the use of Lyapunov functional method, for the input strict passivity and the output strict passivity, respectively. Then delay-dependent sufficient conditions are presented to ensure the uncertainty SDRDSs to achieve the robust passivity. Moreover, by utilising the techniques of Green formula and Poincare's inequality, the difficulty is handled caused by the boundary input and boundary controller. Besides, the troubles brought by the existence of the stochastic term and uncertain parameters are resolved by stochastic inequality techniques. Finally, numerical simulations are provided to show the validity of our theoretical results.

Optimal Energy Shaping via Neural Approximators

We introduce optimal energy shaping as an enhancement of classical passivity-based control methods. A promising feature of passivity theory, alongside stability, has traditionally been claimed to be intuitive performance tuning along the execution of a given task. However, a systematic approach to adjust performance within a passive control framework has yet to be developed, as each method relies on few and problem-specific practical insights. Here, we cast the classic energy-shaping control design process in an optimal control framework; once a task-dependent performance metric is defined, an optimal solution is systematically obtained through an iterative procedure relying on neural networks and gradient-based optimization. The proposed method is validated on state-regulation tasks.

Online reinforcement learning with passivity-based stabilizing term for real time overhead crane control without knowledge of the system model

Due to the existing uncertainties such as the payload mass and unmodeled dynamics in the overhead crane system, classical model-based control methods yielding fixed control gain can exhibit certain limitations. In this study, a novel model-free online Reinforcement Learning (RL) control method is proposed for the real-time overhead crane position regulation and anti-swing control problem, combining the benefits of adaptive control and optimal control. The crane control problem is first formulated as an optimal regulation problem with a user-specified objective function. Then, an improved neural-network updating rule with an additional passivity-based stabilizing term is developed to ensure the system stability during learning based on the overhead crane system passivity analysis. The proposed method, unlike other online RL algorithms, does not require the initial stabilizing control policy or prior knowledge of the crane mathematical model. Lyapunov approach is used to prove the closed-loop system stability, and the learned controller is shown to be near-optimal within a finite bound. Finally, simulation studies are conducted to demonstrate the effectiveness of the proposed method in the presence of system parameter variations and external disturbances, exhibiting satisfactory performance when compared to LQR and passivity-based control.

On control of voltage-actuated piezoelectric beam: A Krasovskii passivity-based approach

This paper presents a new passivity property for distributed piezoelectric devices with integrable port-variables. This novel passivity-based control approach is suited for dissipative systems. We present two new control methodologies by exploiting the integrability property of the port-variables. The derived controllers have a Proportional-Integral (PI) like structure and are shown to asymptotically stabilize the piezoelectric devices. Finally, simulation results are presented for both controllers for a PZT-4 piezoelectric device.

Passivity-Based Control of Multiple Quadrotors Carrying a Cable-Suspended Payload

In this article, a new passivity-based controller is proposed for stable cotransportation of a cable-suspended payload by a number of quadrotors. Nominal proportional–derivative position controllers with desired acceleration feedforward are augmented with time-varying dissipative terms to account for the drones’ underactuation. A storage function is defined that includes terms inspired by the kinetic and potential energies of the system components as well as virtual energy of the controller. A time-domain passivity observer is used in conjunction with an adaptive dissipative term to ensure that the value of the storage function is continuously decreased and, hence, guarantees closed-loop stability. Moreover, barrier Lyapunov functions are employed to avoid interdrone collisions. The proposed controller makes no assumption about and requires no knowledge of the cables’ tension status. Additionally, it requires no measurement from the payload. The cables can be attached to the quadrotors and the payload at arbitrary points. Experiments with a system of three quadrotors and a cable-suspended payload demonstrate the effectiveness of the proposed approach.

Passivation and Passivity-Based Control of DC–DC Converter With Unknown Constant Power Loads

The loads of dc–dc converter (DDC) are mostly constant power loads (CPLs) in dc microgrid. Due to the negative impedance characteristic, CPLs may lead to the nonpassive factor in DDC. Thus, it may result in DDC, not operating reliably at the desired operating point. In this article, a nonlinear controller based on passivity-based stability theory is proposed for the DDC with CPL, which will improve the stability of the converter. Through damping and interconnection injecting, the alternating component passivity-based controller (PBC) is designed to realize the unified control of output voltage and inductor current. It could realize the passivation of alternating component. Furthermore, this controller can solve the problem of traditional PBCs to control inductor current or output voltage only. Moreover, a power observer is adopted, which could fast estimate the variation of the CPL and improve the adaptability of DDC when CPL changes. The proposed controller not only ensures the stability of DDC under large variation of CPL, but also features fast dynamic response with accurate tracking over wide operating range. Finally, the feasibility and effectiveness of the proposed controller are verified by simulation and experimental results.

A State Observer for Sensorless Control of Power Converters With Unknown Load Conductance

In this article, the sensorless control problem of a large class of power converters with unknown load conductance is investigated. A reduced-order generalized parameter estimation-based observer (GPEBO) is presented to reconstruct the unmeasurable states and estimate the unknown load conductance of the system. Three nice features of this observer are as follows: finite-time convergence (FTC) is guaranteed, an alertness preservation is imposed to be able to estimate a possibly time-varying load, and the required excitation condition is very weak and can be satisfied in normal operation of power converters. Then, replacing the estimated states and parameter, in a certainty equivalent manner, in a PI passivity-based controller, a sensorless control scheme is proposed to stabilize the systems with exponential convergence. By virtue of the FTC property of the GPEBO, the global exponential stability of the overall closed-loop system is established. Simulation and experimental results of the proposed controller with application to the boost and Ćuk converters are given to assess its effectiveness.

The Effect of Replacing Si-MOSFETs with WBG Transistors on the Control Loop of Voltage Source Inverters

The operation of a voltage source inverter (VSI) depends on its output LC filter and the PWM modulator delay. The VSI model includes serial equivalent resistance based on the resistances of the active inverter bridge transistors, the filter coil winding, and additional PCB elements, such as traces and connectors, in addition to the large equivalent resistances that result from power losses in the coil core and switches. These dynamic power losses depend on the switching frequency and the inverter load. This paper investigates the change in equivalent serial resistance that occurs if the standard Si-MOSFET switches are replaced with wide bandgap (WBG) transistors with correspondingly lower equivalent serial resistance. The paper further investigates how such a change influences the design of the controller, given that replacement of the switches shifts the roots of the closed-loop characteristic equation. Theoretical analyses of the influence of equivalent serial resistance for a multi-input single-output passivity-based controller and a single-input single-output coefficient diagram method are also presented. These analyses are applied to both types of switches. Two methods are used to measure the serial equivalent resistance for a given VSI using Si and WBG switches. The possibility of replacing switches with WBG technology in existing inverters was assessed, and the corresponding controller adjustment that would be required. The theoretical analysis is verified via the use of an experimental VSI.