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This study presents a real-time optimal torque control scheme for interior permanent magnet synchronous motors (IPMSMs). The proposed scheme enables computation of optimal current reference for a torque reference under all operating regions, including the maximum torque per ampere (MTPA), flux weakening (FW), maximum current (MC), and maximum torque per voltage (MTPV), using numerical optimization techniques to simplify the problems and obtain the corresponding solutions with reduced computation burden. Linearizing the torque equation of IPMSM is utilized to derive solutions for the MTPA and FW. These solutions are proved to converge to their optimum with the aid of the reference smoother. Numerical solutions for the MC and MTPV are derived based on the assumption that the resistive voltage drop is small enough but not zero. These solutions differ from the existing solutions that ignore the resistive voltage drop. The effectiveness of the proposed method is numerically and experimentally verified using a 7.5-kW IPMSM with a considerable reduction in computational time of approximately 90% in the simulation compared with the analytic solution.

In this article, the position-tracking problem for magnetic levitation (MAGLEV) systems is addressed by handling the model nonlinearities and uncertainties of parameters and loads. The first feature is devising a variable cut-off frequency algorithm enhancing the transient tracking performance by updating the feedback gain accordingly. The second is introducing the disturbance observer (DOB) improving the disturbance attenuation performance with the offset-free property, which corresponds to the replacement of tracking error integrators. The simulation results numerically demonstrate the effectiveness of the proposed technique considering model-plant mismatches and load variations.

This brief proposes an advanced positioning law for hybrid-type stepper motors with two main features: a) a combination of pole-zero cancellation-based proportional-integral control with disturbance observers and b) a variable manifold forced to be exponentially convergent by the proposed control law. The parameter and load uncertainties are also explicitly handled in the controller design task. The practical improvement is confirmed with experimental evidence using a 10-W stepper motor controlled by two dual half-bridge drivers and a 32-bit digital signal processor.

This paper suggests a novel model-based nonlinear DC motor speed regulator without the use of a current sensor. The current dynamics, machine parameters and mismatched load variations are considered. The proposed controller is designed to include an active damping term that regulates the motor speed in accordance with the first-order low-pass filter dynamics through the pole-zero cancellation. Meanwhile, the angular acceleration and its reference are obtained from simple first-order estimators using only the speed information. The effectiveness is experimentally verified using hardware comprising the QUBE-Servo2, myRIO-1900, and LabVIEW.

This paper suggests a position-tracking algorithm for the outer-loop through the invariant dynamic surface approach for balancing robot applications. The main feature is to devise a dynamic surface representing the target position-tracking performance with variable cut-off frequency. The proposed controller makes the dynamic surface invariant while updating the closed-loop cut-off frequency accordingly with the self-tuner. The closed-loop properties are rigorously analyzed. The experimental verification result shows that the proposed controller establishes the 48% enhancement of the circular tracking performance in comparison with the feedback linearization method, where the LEGO Mindstorms EV3 is used.

This brief presents an advanced proportional-derivative (PD) voltage control mechanism for DC/DC boost converters suffering from the parameter and load variations. The proposed controller eliminates the requirement for current feedback by designing the first-order observer estimating the voltage derivative without the use of converter parameters, which corresponds to the first contribution. As another contribution, a specific feedback gain structure for PD-loop and the active damping component guarantees the first-order closed-loop transfer function from the reference to the output voltage by the stable pole-zero cancellation. A prototype bi-directional 3-kW boost converter experimentally validates the closed-loop performance of the proposed technique.

This brief presents a novel energy-shaping technique-based speed controller for permanent-magnet synchronous motors (PMSMs) considering machine nonlinearities and load and parameter changes. There are three features: The time-varying damping term is injected into the speed loop, which is automatically updated by the proposed self-tuner. The disturbance observers are designed for both the speed and current loops to achieve better disturbance rejection performance with removal of offset errors without the use of tracking error integral actions. Furthermore, the closed-loop analysis result is provided to demonstrate its beneficial closed-loop properties. The practical advantages are experimentally verified in several convincing scenarios with a prototype 500-W PMSM driven by a three-phase inverter.

This paper develops an observer-based positioning scheme for ball-beam systems considering actuator dynamics. The practical constraints are handled systematically, including the mechanical dynamical nonlinearities, mismatched load disturbances, and parameter uncertainties. This result provides contributions as follows. First, parameter-independent observers exponentially estimate the ball velocity, motor speed, and its acceleration to remove the velocity, motor speed, and current feedback. Second, the auto-tuner automatically adjusts the desired closed-loop input-output behaviors to update its cut-off frequency in the transient operations. Third, observer-based active damping injection reduces the closed-loop ball position and actuator speed dynamics to 1 by pole-zero cancellation. Finally, disturbance observers act as a dynamic compensator by estimating the disturbances from model-plant mismatches such as dynamic nonlinearities, mismatched load disturbances, and parameter variations. The experimental study verifies the applicability of the proposed technique using the Quanser Ball-Beam hardware driven by an SRV02 servomotor.

This brief proposes a proportional-type angle filter with the variable feedback gain mechanism for motor drives using the encoder for angle feedback. In this case, the angle measurement suffers from discontinuity that has to be made continuous through low-pass filters and observers. There are three features. The first designs a real-time feedback gain update rule to improve the closed-loop filtering performance by magnifying the feedback gain in transient periods. The second introduces the disturbance observer (DOB) in the resultant proportional-type feedback filter for enhanced disturbance attenuation against the speed variations. The third proves the useful properties of the filtering error convergence and performance recovery by investigating the filtering error dynamics. A prototype 500-W permanent-magnet synchronous motor (PMSM) drive system validates the practical advantages of the proposed technique.

This article proposes intelligent nonlinear web tension and velocity controllers for roll-to-roll printing systems. The introduction of the perturbed machine model makes it easy to handle machine nonlinearities and parameter variations, simultaneously, with the simple static and first-order dynamic compensator. The feedback gains of web tension and velocity are automatically updated by the proposed self-tuner, which corresponds with the first feature of this article. As the second feature, the introduction of disturbance observers in place of the regulation error integrators provides an improved disturbance rejection performance and offset-free property, which is rigorously analyzed based on the Lyapunov stability criterion. The closed-loop performance improvement is numerically demonstrated under various scenarios using MATLAB/Simulink.

This study devises a variable-performance control law for rover vehicles servoing velocity and pitch angle commands. This considers both vehicle and actuator dynamics as well as load and parameter variations. The main merits are summarized as follows. First, the proposed auto-tuning law magnifies the feedback gain for desired systems to achieve transient performance improvement with the convergence property guarantee. Second, the collaboration of pole-zero cancellation controller and disturbance observers eliminates over/undershoots through closed-loop order reduction by a special form of feedback gain. Beneficial closed-loop properties are also derived from the closed-loop analysis. The prototype rover vehicle built with TETRIX and MyRIO-1900 experimentally validates the closed-loop performance and robustness improvement.

This study presents a solution to the position stabilisation problem for non-linear magnetic levitation systems using the only position measurement. This considers parameter and load variations without the use of current and velocity feedback. The features are given as follows: (i) the removal of current and velocity feedback by the proposed first-order state estimators without system parameters, (ii) securing of improved closed-loop robustness from the combination of active damping and specified feedback gain with the closed-loop system order reduced to 1 and (iii) proof of performance recovery and offset-free in the absence of regulation error integral actions. The numerical simulations verify the performance and robustness improvements through realistic scenarios.

This study addresses the position-tracking problem for hybrid-type stepper motors in the rotational $d-q$ coordinate system. The proposed controller aims to govern position behavior with the desired low-pass filter from the reference (input) to the position (output). A perturbed form of machine dynamics is adopted to handle both parameter variations and load uncertainties and the control law has two main advantages. First, the real-time auto-tuner increases the closed-loop cut-off frequency during transient periods and restores it to its nominal value as it approaches the steady state. Second, disturbance observers improve the closed-loop robustness against high-frequency disturbances and ensure the offset-free property without additional integral actions. The experimental results validate the practical advantages from the proposed controller with a 10-W prototype stepper motor control system.

This brief exhibits a nonlinear self-tuning position stabilization algorithm for ball-beam system applications under the consideration of parameter uncertainties and actuator dynamics.; there are two major contributions. First, a first-order ball velocity estimator is proposed using only the ball position feedback without dependence on system parameters. Second, the resulting nonlinear controller incorporates the time-varying feedback gain driven by the proposed self-tuner. Third, a first-order disturbance observer (DOB) is introduced to remove the high-frequency disturbance attenuation performance. The various simulation results-based-on MATLAB/Simulink validate the practical merits of the proposed scheme.

In this article, we deal with the one-step time-delay problem in power converter and motor drive system applications implemented by the digital signal processor. For these wide applications, a novel one-step time-delay compensation algorithm is proposed, comprising a standard Luenberger-type observer including a learning algorithm and disturbance observer (DOB). The first novelty is to suggest the learning algorithm automatically determining the observer feedback gains according to the estimation error magnitude. The second is to introduce DOBs with estimation error integrators for removing the steady-state estimation errors, removing the additional adaptive and nonlinear damping compensation terms. The closed-loop observer behaviors are rigorously analyzed to present useful properties. The experimental data obtained using a 3-kW prototype dc–dc boost converter validates the effectiveness of the proposed algorithm.

This brief proposes an auto-tuning proportional-type synchronization controller for dc motor speed applications with consideration of parameter and load variations. The proposed algorithm is comprised of two parts: a proportional-type speed tracking controller with a disturbance observer (DOB) and second a synchronizer driven by an auto-tuning algorithm. The first feature is to propose an auto-tuning synchronizer to reduce synchronization error during transient operations. The second is to introduce a DOB so that the proportional-type controller guarantees tracking and synchronization performance recovery without offset error. Experimental data is provided to convincingly show the effectiveness of the suggested scheme using a 50-W dual dc motor drive system.

This paper presents a nonlinear tracking controller including the cutoff frequency adaptation algorithm for quadcopters without the use of true plant parameters. This study makes two contributions. First, an adaptation algorithm automatically updates the closed-loop cutoff frequency by updating the feedback gains. Second, a nonlinear control law renders the closed-loop system to guarantee the exponential performance recovery and offset-free properties, while only using the proportional component of tracking errors. The numerical verifications are performed to verify the closed-loop performance improvement from the proposed controller with MATLAB/Simulink.

This letter devises a novel signal-filtering technique subject to the feedback structure without the exact source signal dynamics information. The main idea of this result is comprised of two parts: first, the combination of the Luenberger and disturbance observer design techniques to improve the disturbance rejection capability in the feedback structure; second, the closed-form filtering gain-boosting mechanism updating the gain into the direction of the filtering error reduction. It is experimentally confirmed that the proposed filter contributes to lowering the current regulation performance degradation level from the filtering performance improvement using a 500-W permanent-magnet synchronous motor driven by the three-phase inverter.

In this brief, a novel nonlinear tracking control law is presented for dc/dc boost converter voltage control applications through the energy-shaping approach. The first feature is to devise a self-tuner to update the invariant surface according to the output voltage-tracking error. The second is to prove that the exponential convergence and performance recovery properties without steady-state errors under the use of the nominal parameter information of converters. A 3-kW prototype dc/dc boost converter is adopted for experimental verifications of the proposed controller.

This paper exhibits a robust speed controller equipped with a self-tuner for permanent magnet synchronous motors (PMSMs), taking nonlinearity and model-plant mismatches into account. The first contribution of the proposed technique is designing a self-tuner for updating the cutoff frequency of target speed dynamics. The second one is rendering the closed-loop system to recover the target tracking performance and remove the offset errors in the absence of integrators. A 5-kW prototype interior PMSM is used to experimentally verify the effectiveness of the proposed technique.

This study suggests a non-linear control algorithm for the exciter controlling a single-machine infinite-bus system, considering the non-linear dynamics with parameter and sudden input power variations. This study provides three contributions: (i) an estimation algorithm is designed to estimate the power angle operating point for the terminal voltage to be regulated to its desired value, incorporating the disturbance observer (DOB); (ii) a DOB-based proportional-type non-linear stabilising algorithm is systematically derived using the estimated power angle operating point; and (iii) it is rigorously shown that the proposed proportional-type non-linear controller always removes the steady-state errors without integral actions for error variables. The simulation results confirm the effectiveness of the proposed technique under several transmission line fault scenarios.

In this paper, a robust position tracking controller is proposed using an invariant dynamic surface approach in a cascade control system structure. There are two main contributions. The first is to design a dynamic surface giving the desired tracking-performance with a time-varying cutoff frequency automatically adjusted by the proposed auto-tuner, which can enhance the reliability of the resulting control system. The second is to derive the inner- and outer-loop control laws driving the closed-loop trajectories to the dynamic surface, incorporating a disturbance observer with the use of only nominal plant parameters. A reduction of plant parameter dependence can be accomplished by the second contribution. The realistic simulation results confirm the advantages of the proposed technique.

This article exhibits an output voltage-tracking control algorithm incorporating a self-tuning algorithm and disturbance observers (DOBs) for dc–dc boost converters without tracking error integrators, considering model nonlinearities, parameter variations, and load uncertainties. The proposed algorithm is designed such that it forces the output voltage to track its target trajectory driven by a time-varying low-pass filter (LPF), despite model-plant mismatches. This paper makes two main contributions. First, it constructs the self-tuning algorithm by updating the closed-loop cut-off frequency in the time-varying LPF to improve the transient tracking performance. Second, it embeds first-order DOBs in the proportional-type nonlinear controller to achieve both performance recovery and the offset-free properties. The experimental verifications are carried out to illustrate the effectiveness of the closed-loop system driven by the proposed technique with a 3-kW prototype dc–dc boost converter; the 46% improvement of the tracking performance is observed, compared with the conventional feedback-linearization controller.

This study suggests a proportional-type output-voltage control algorithm of a three-phase inverter for uninterruptible power supply applications with performance-recovery and offset-free properties. It makes the two contributions. The first one is to introduce first-order disturbance observers (DOBs) so as to exponentially estimate disturbances originating from model-plant mismatches. The second one is to rigorously prove that the proposed proportional-type feedback-linearising controller equipped with DOBs guarantees performance-recovery and offset-free properties. The experimental results conducted in this study, which uses a 10 kW three-phase inverter with an output capacitor, confirm that the closed-loop performance is satisfactory in both transient and steady-state periods.

In this paper, a robust output voltage-tracking algorithm is proposed for dc/dc boost power conversion systems based on a variable invariant manifold. A systematic multivariable approach, considering not only nonlinearity but also the parametric uncertainties, is used for deriving the control law. The proposed method has two features. First, a variable cut-off frequency algorithm is constructed to automatically adjust the invariant manifold, improving the transient output voltage-tracking performance. Second, nonlinear disturbance observers are introduced to enable the control law to exponentially recover the desirable tracking performance without any offset errors in the variable invariant manifold. The performance of the proposed technique is experimentally confirmed with a 3-kW dc/dc boost power conversion system.

This paper deals with the reduction of torque ripple in a PMSM (permanent magnet synchronous motor) drive using disturbance observer based control. The current ripple is periodically synchronized to the position of the rotor in the form of distorted back-EMF voltage. Therefore, the current ripple is concentrated on the rotation frequency and integral multiples in the frequency domain. In this paper, a method is introduced to reduce the current ripple while maintaining reference tracking performance without a significant change of the controller by intensively increasing the disturbance suppression performance of the frequency band corresponding to the current ripple. The proposed method is verified that a steady-state 58% ripple reduction in 500W SPMSM in the experiments.

In this paper, a new method is proposed for the real-time estimation of the full parameters of a permanent magnet synchronous motor (PMSM) that is based on the stator current ripple model. By introducing the stator current ripple model together with the known two state equations for the $d$ - and $q$ -axes currents, we resolve the rank deficiency problem, thus enabling real-time full parameter estimation even in the steady state. A signal processing technique for removing adverse effects from noises and uncertainties existing in the stator current ripple measurement is also presented. The efficacy of the proposed method is verified by simulation on a 15-kW PMSM, and both the proposed and conventional methods are compared.

This study presents an advanced current control of permanent magnet synchronous motor (PMSM) aiming for improved transient performance over a wide speed range. While the conventional current control scheme based on proportional-integral controllers often shows a degraded transient performance in high-speed operation where the control inputs are almost saturated, the proposed scheme uses a proportional current controller in combination with a disturbance observer, by which the current error converges to zero in an exponential way. This desirable property preserves the transient performance even under the input constraint. A systematic way to determine the optimal control gain considering parameter uncertainties is also provided. A simulation study verifies the efficacy of the proposed scheme using a 20 kW PMSM model in comparison with the conventional current control scheme.

This paper presents an offset-free global tracking control algorithm for the input-constrained plants modeled as controllable and open-loop strictly stable linear time invariant (LTI) systems. The contribution of this study is two-fold: First, a global tracking control law is devised in such a way that it not only leads to offset-free reference tracking but also handles the input constraints using the invariance property of a projection operator embedded in the proposed disturbance observer (DOB). Second, the offset-free tracking property is guaranteed against uncertainties caused by plant-model mismatch using the DOB’s integral action for the state estimation error. Simulation results are given in order to demonstrate the effectiveness of the proposed method by applying it to a DC/DC buck converter.

This article exhibits a nonlinear proportional-type position tracking controller for DC motors, taking the parameter and load variations into account. The proposed method makes two contributions. First, a first-order disturbance observer (DOB) is devised in order to exponentially estimate the disturbances caused by parameter and load uncertainties. Secondly, a proportional-type nonlinear position tracking controller is constructed by incorporating the resulting DOB in order to ensure two useful closed-loop properties; namely, performance recovery and offset-free properties without the tracking error integral actions. The experimental result confirms the efficacy of the proposed method where a 30-W DC motor is used with an half bridge inverter.

This article suggests a cascade output voltage regulation algorithm for an N-phase interleaved DC/DC boost converter based on reference dynamics. The proposed algorithm has two advantages. The first is to guarantee the performance recovery property using the reference dynamics in the presence of a model-plant mismatch, and the second is to present a systematic procedure determining the stabilising control gains by solving an optimisation problem. The closed-loop performance of the proposed method is evaluated through simulations and experiments using a 3-kW four-phase interleaved DC/DC boost converter where the proposed method is compared with the feedback linearising method.

In this article, a variable sliding surface-based output voltage tracking controller is proposed for three-phase rectifiers driven by the pulse-width modulation technique. A systematical multi-variable approach is used for deriving the control law, considering the not only non-linearity but also parametric uncertainties. The proposed method has two features. First, the non-linear first-order disturbance observers are introduced to enable for the control law to exponentially recover the desirable tracking performance without any offset-errors in the sliding mode. Second, the self-tuning algorithm is designed to update the sliding surface to enhance the output voltage tracking performance in transient periods. The performance of the proposed method is experimentally demonstrated by using a 3-kW three-phase rectifier.

This article suggests a robust cascade speed control algorithm for a permanent magnet synchronous motor (PMSM) combining the classical feedback linearising (FL) method and the disturbance observers...

This study presents a proportional-type non-linear current control algorithm for permanent magnet synchronous motors (PMSMs) with performance recovery and offset-free properties. The contribution falls into two parts. First, the disturbances from the model-plant mismatch are exponentially estimated by the proposed first-order convergent disturbance observers. Second, it is proven that the proposed algorithm guarantees the performance recovery and offset-free properties, also stabilises the first-order internal dynamics that arise from the PMSM speed dynamics. The closed-loop performance was shown by the simulations and experiments by using a 5 kW interior PMSM.

This article proposes a proportional-type cascade output voltage control algorithm equipped with disturbance observers for a three-phase AC/DC converter considering a model-plant mismatch. The advantages of the proposed method are grouped into two. First, a simple first-order disturbance observer is devised for both inner and outer-loops, not only to recover the target closed-loop performance, but also to eliminate steady state offset errors. Second, it is thoroughly verified that the entire closed-loop system driven by the proposed proportional-type cascade controller is stable. The efficacy of the proposed method is experimentally investigated using a 3–kW AC/DC converter.

This study exhibits a self-tuning speed control scheme for the surface-mounted permanent magnet synchronous motor (SPMSM) against the parameter variations through the multivariable approach. The proposed method has two novelties. The first one is to combine the adaptive controller with the self-tuning algorithm so as to make the decay ratio of the tracking errors higher in the transient period. The second one is to provide a systematical way to find a robust stabilizing control gain corresponding the speed and current tracking errors by solving an optimization problem. The efficacy of the proposed method was experimentally investigated using a 3- kW SPMSM.

This paper presents a self-tuning speed control scheme for the surface-mounted permanent magnet synchronous motor (SPMSM) against parameter variations with the traditional vector control strategy. The proposed control strategy has three novelties; the first one is to design the inner- and outer-loop controllers to stabilize the current and speed dynamics with the self-tuning algorithm for a better transient performance, the second one is to give a systematic way to constitute a robust optimal control gain by solving an optimization problem, and the third one is to show that the proposed inner-loop controller also stabilizes the closed-loop system, including the first-order internal dynamics caused by the SPMSM speed. The efficacy of the proposed method was verified through experiments using a 3-kW SPMSM.

In this study, a fast and accurate optimal torque control scheme for interior permanent magnet synchronous motors (IPMSMs) is presented, which enables computing the optimal current references for maximum torque per ampere (MTPA) and flux weakening (FW) operations. Instead of analytically solving the optimal torque control problem that involves computationally expensive quartic equations, a numerical optimization technique is introduced to simplify the problem and solve it in iterations with reduced computation burden. Under the reasonable assumption of a slowly varying torque reference, linearizing the IPMSM torque equation helps to derive the solutions for the MTPA and FW operations in simpler forms. Unlike conventional numerical methods, convergence to the exact solution is ensured. A simulation using a 7.5-kW IPMSM model in MATLAB verifies the effectiveness of the proposed method by comparing it with the conventional methods in terms of solution accuracy and computational efficiency.

This study seeks an advanced sensor fault diagnosis algorithm for DC/DC boost converters governed by nonlinear dynamics with parameter and load uncertainties. The proposed algorithm is designed with a combination of proportional-type state observer and disturbance observer (DOB) without integral actions. The convergence, performance recovery and offset-free properties of the proposed algorithm are derived by analyzing the estimation error dynamics. An optimization process to assign the optimal feedback gain for the state observer is also provided. Finally, a fault diagnosis criteria is introduced to identify the location and type of sensor faults online using normalized residuals. The experimental results verify the effectiveness of the suggested technique under variable operating conditions and three types of sensor faults using a prototype 3 kW DC/DC boost converter.

This paper presents a novel output voltage regulator in the cascade structure under the consideration of both the parameter and load uncertainties. It leads to the first-order closed-loop inner and outer loop dynamics in the low-pass filter form by the pole-zero cancellation through the active damping injection, which is the main contribution of this study. Moreover, it is proved that the active damping injection level determines the disturbance rejection capability of the closed-loop system. A 3-kW DC/DC boost converter confirms the actual advantages from these two contributions.

This paper presents a simple input-constrained current controller for a DC/DC boost converter with stability analysis that considers the nonlinearity of the converter model. The proposed controller is designed to satisfy the inherent input constraints of the converter under a physically reasonable assumption, which is the first contribution of this paper. The second contribution is providing a rigorous proof of the proposed control law, which keeps the closed-loop system along with the internal dynamics stable. The performance of the proposed controller is demonstrated through an experiment employing a 20-㎾ DC/DC boost converter.

This paper suggests an offset-free one-step ahead state predictor for power electronic applications such as power converters and motor drives in the presence of plant uncertainties. The proposed method is devised through the robust proportional–integral observer technique, considering the full state as the output, and it has the two advantages: 1) to adopt the integrator of the state estimation error for ensuring the offset-free state prediction performance and 2) to introduce the nonlinear damping term so that it suppresses the disturbances originated from a plant-model mismatch. Performing the realistic simulations based on the PowerSIM software, it is shown that the proposed method provides an efficient one-step ahead state prediction performance despite the plant uncertainties.

This paper presents an adaptive speed tracking control scheme for an uncertain surface-mounted permanent magnet synchronous motor (SPMSM) without any knowledge of the SPMSM parameters and the singularity problem; further, even the upper and lower bounds of the parameters are not necessary. The contribution of this study is twofold. The first one is to introduce a coordinate transformation so that the resulting controller does not suffer from a singularity problem caused by the denominator including the parameter estimates. Besides, although the number of the unknown parameters is increased by two times, the number of estimators is the same as the previous result. The second one is to prove that the slightly modified parameter adaptation law contributes in enhancing the closed-loop robustness against the disturbance caused by the time-varying component of the load torque. The effectiveness of the closed-loop performance is shown by performing the experiment using the 3-kW SPMSM without any SPMSM parameter knowledge.

This paper exhibits a passivity-based robust output voltage controller for DC/DC boost converters for wind power system applications. The proposed technique has two features. The first one is to introduce a nonlinear disturbance observer for estimating the disturbances arising from the load and parameter variations. The second one is to derive a proportional-type passivity-based output voltage tracking controller incorporating the disturbance observer output, which simplifies the control algorithm by removing the use of tracking error integrators and an anti-windup algorithm. These two features constitute the useful closed-loop properties called the performance recovery and offset-free properties. Numerical simulation results confirm the efficacy of the proposed scheme, where a wind power system including the proposed controller is emulated using the PowerSIM software.

This paper presents a robust current tracking controller for permanent magnet synchronous motors (PMSMs) with a performance recovery property for electric power steering (EPS) applications. The contributions of this work are twofold. First, a disturbance observer (DOB) is designed to compensate the disturbances arising from the model–plant mismatches while reducing the closed-loop sensitivity. Second, a current controller is designed to improve the current tracking performance in the frequency domain by assigning the performance recovery property to the closed-loop system. The closed-loop performance is verified through simulations and experiments using a 500 W PMSM connected to an EPS system.

This article presents a robust speed tracking algorithm for a permanent magnet synchronous generator utilized for wind power generation systems, considering the machine parameter and load uncertainties. There are two major contributions: (a) a disturbance observer is designed to exponentially estimate disturbances from the model-plant mismatches and severe load torque variations, and (b) it is included in a nonlinear cascade-type proportional speed tracking controller to establish the performance recovery and offset-free properties without the use of tracking error integrators. A simulation result numerically verifies the effectiveness of the proposed technique, where the PowerSIM software emulates a wind power generation system.

This paper proposes an offset-free proportional-type output voltage-tracking algorithm embedding the disturbance observers (DOBs) for the N-phase interleaved DC/DC boost converter through a systematical multivariable approach. The contributions of this article fall into two parts. The first one is to design the first-order nonlinear DOBs for exponentially estimating the disturbances caused by the model-plant mismatches. The second one is to prove that the proposed proportional-type controller equipped with the DOBs guarantees the performance recovery property as well as the offset-free property. The performance of the proposed method is evaluated through simulations and experiments using a 3-kW four-phase interleaved DC/DC boost converter, comparing the proposed and feedback linearizing (FL) methods.

This paper presents a cascade output voltage control strategy for an uncertain DC/DC boost converter adopting an adaptive current controller in its inner loop. Considering the non-linearity, load uncertainties and parameter uncertainties of the converter, the proposed controller is designed following the conventional cascade voltage controller design method. The proposed method makes the following three contributions. First, a coordinate transformation is introduced for the inner loop, enabling avoidance of the singularity problem caused by the estimates of uncertain parameters. Second, a slight modification to the adaptation law is performed to guarantee closed-loop stability in the presence of the time-varying component of the load current. Third, the outer-loop controller is devised such that its performance can be adjusted without any parameter information. The closed-loop performance is demonstrated through simulations and experiments using the DSP28335 with a 3 kW DC/DC boost converter.

This study proposes a proportional-type position controller for the DC motor with the performance recovery property. The proposed method has two merits. First, the disturbance observers are designed so as to make up for the model-plant mismatches. Second, based on the classical cascade structure, a proportional-type position controller is developed via the feedback linearizing technique with the guarantees of the performance recovery and offset-free properties. The efficacy of the proposed method is evaluated by the simulations using the Simscape toolbox and level-2 S-function in MATLAB/Simulink.

This study proposes a disturbance observer-based proportional-type DC-link voltage tracking algorithm for permanent magnet synchronous generators (PMSGs). The proposed technique feedbacks the only proportional term of the tracking errors, and it contains the nominal static and dynamic feed-forward compensators coming from the first-order disturbance observers. It is rigorously proved that the proposed method ensures the performance recovery and offset-free properties without the use of the integrators of the tracking errors. A wind power generation system has been simulated to verify the efficacy of the proposed method using the PSIM (PowerSIM) software with the DLL (Dynamic Link Library) block.