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Simplified models to calculate the change of stator flux and torque of permanent magnet synchronous motor (PMSM) on stator flux coordinate system are proposed. In order to solve high torque ripples of PMSM direct torque control (DTC) system, dead-beat (DB) control of stator flux and torque is proposed. The calculation of ideal voltage vector (VV) for the DB control of stator flux and torque using simplified models are given, and a simplified VV selecting method is used to implement the DB control. In order to improve control performances, a novel way to expand VVs based on both angle and amplitude is proposed. The angle and amplitude of ideal VV are used to determine the angle and amplitude of output VV and the look-up table is used to generate output VVs. Simulation results show this novel method can decrease stator flux and torque ripples dramatically, but increase switching frequency.

This paper presents a dead-beat control algorithm for Uninterruptible Power Supply (UPS) applications of single-phase inverters. The proposed control method requires the measurement of capacitor current and output voltage in order to keep the output voltage sinusoidal ensuring high dynamic performance even under load changes. The dead-beat controller optimizes the behavior of the system by eliminating the error between the output and the reference voltage without increasing the number of current sensors, which are costly, and eliminates load voltage distortions and restores the system state in the event of external shutdown-loop road interference. In this paper, we propose a capacitor current estimation based on the Luenberger observer. Processor-In-the-Loop (PIL) is a test method that allows us to create and evaluate controllers by running built-in C code on the DSP scheduled for the controller during simulated PSIM power phase control. It can be seen that the simulation results match the PIL test results, which proves the validity of the proposed controller.

In this paper, a sample voltage dead-beat control based on differentiative voltage prediction (DVP) and switching-cycle extension (SCE) is presented to achieve optimal transient response for DC-DC converters under discontinuous conduction mode (DCM) operation. Firstly, to improve load transient response, a DVP method is proposed to estimate the load. With the estimated load, the controller realizes load current feedforward and thus improves the transient response with a wide load range. Secondly, an SCE strategy is proposed to enlarge the output current range and output voltage slew rate, both of which have limited value under conventional digital pulse width modulation (DPWM). When the output current reaches the limited value, the proposed strategy increases the switching cycle to enlarge the current range without losing DCM operation. Finally, combining DVP with SCE, the converter not only achieves optimal response in large signal transients, but also doubles the load range in DCM operation. [ABSTRACT FROM AUTHOR]

Aiming at improving the performance of the existing for single-phase electric springs (ESs), such as the fastness of the voltage stabilization and the mitigation of the voltage harmonics across the critical loads (CLs), the dead-beat control cooperating with state observer is proposed in this paper. First, the δ control is reviewed, outlining its features of regulation of the CL voltage while keeping the ES operation stable. After describing the operation of an ES in the continuous-time domain by the state-space technique, its discrete-time model is formulated using the zero-order-hold (ZOH) algorithm. Then, the control system for an ES is designed around the dead-beat control cooperating with a state observer and implementing the two typical compensation functions achievable with the δ control, namely the pure reactive power compensation and the power factor correction. Results obtained by simulation demonstrate that the control system is able to both properly drive an ES and to implement the two functions. The results also show that the proposed control system has the advantage of eliminating harmonic components in CL voltage when grid voltage distorts.

In this paper, a novel approach for finite-time average consensus within a prescribed time is introduced and explored for a multi-agent system running ordinary nearest-neighbor protocols. Differently from the available approaches of finite-time consensus, it exploits the special motion of one agent properly tuned, through an appropriate algorithm based on past values of its own local data. The leader’s motion influence input is built upon a set of internal variables, and it is designed to achieve a finite-time transient behavior while keeping the initial consensus value unchanged. A preliminary procedure is set to retrieve the algorithm’s parameters from data collected in an initial experimental stage, so that the overall algorithm can be run in a fully data-driven fashion. Simulation results put in evidence the effectiveness of the approach, together with some features and drawbacks of the proposed algorithm, so they draw some important insights regarding its use and future research lines.

Aiming at the two-vector model predictive current control(TV-MPCC)strategy of permanent magnet synchronous motor (PMSM), in a sampling period, can merely change the amplitude magnitude by adjusting the action time of the zero vector, resulting in the synthesized voltage vector direction can only be fixed in the direction of the six basic voltage vectors and the current fluctuations generated by the problem. This paper proposes an optimized three-vector model predictive current control (OTV-MPCC) method, which first finds the desired voltage vector and then finds the position angle of the desired vector through the inverse derivation of the formula and determines the sector in which it is located. The two fundamental vectors are selected and the zero vector at the boundary of the sector as the three voltage vectors requires for the model predictive control. Moreover, the time of each vector action is calculated by using the dead-beat control method, and the zero vector is selected by the switching frequency and switching minimum principle, which makes the algorithm computation significantly reduced. The simulation experimental results show that the proposed optimized three-vector model based on the predictive current control strategy can effectively decline the straight-axis and cross-axis current pulsations and enhance the stability of the system.

Dead-beat predictive current control (DPCC) has great potential in the field of motor control due to its fast response. However, it suffers from low robustness due to its sensitivity to parameter variations. In this paper, a DPCC of permanent magnet synchronous motors (PMSM) combined with parameter adaptation is proposed to enhance the robustness of the dead-beat control under parameter misalignment. Firstly, the basic principles of dead-beat current control are introduced. Then, the influence of parameter errors on the control loop of dead-beat current control under imprecise motor parameters is analyzed. To address the issue of imprecise motor parameters, a predictive current control method combined with a parameter-adaptive algorithm is proposed. The motor parameters are identified online, and the parameters of the predictive current controller are modified in real-time to achieve parameter correction. Finally, comparative simulations and performance evaluations are conducted to validate the effectiveness of the proposed method. The results show that the robustness of the current control system is significantly improved, resulting in better control performance when applying the method proposed in this paper.

In this paper, the reference tracking and switching loss minimization problem of grid-tied inverters has been formulated as an integer least square (ILS) problem. It is considered an NP-hard and combinatorial problem due to the binary nature of switching status. A novel modification to the traditional non-recursive sphere decoding algorithm is being proposed in this research to address the implementation of long-horizon control with reduced computational burden. The proposed algorithm demonstrates a significant reduction in computation cost for long horizons resulting in energy minimization. The proposed method exploits the state-space model of the system to predict the sector in the space vector two-dimensional plane in which reference voltage could exist, thereby reducing the search space and time to search for the optimal solution. The proposed algorithm optimizes the utilization of controller resources compared to the conventional approach. The algorithm’s performance has been validated through simulations and Hardware in loop verification, for the performance optimization of a three-phase grid-tied inverter coupled using RL filter.

Byline: Piotr Ostalczyk (Instytut Automatyki, Politechnika Lodzka, 90-924 Lodz, ul. Stefanowskiego18/22, Poland, postalcz@p.lodz.pl); Tomasz Rybicki (Instytut Automatyki, Politechnika Lodzka, 90-924 Lodz, ul. Stefanowskiego18/22, Poland, trybicki@p.lodz.pl) Keywords: Difference equations; discrete-time systems; [...]

Dead-beat controllers for simple Hammerstein systems are investigated. Several designs for nonminimum-time state dead-beat controllers are given for certain classes of simple Hammerstein systems. A general minimum-time state dead-beat controller is presented for a class of simple Hammerstein systems. A design for a family of minimum-time control laws is provided. This enables, to a certain extent, shaping of transient response via choosing an appropriate control law. Finally, the authors design an output dead-beat controller for a class of Hammerstein systems that are not necessarily state dead-beat controllable. Index Terms - Controllability, dead-beat control, discrete-time, Hammerstein systems, time-optimal control.

In the field-weakening region, the traditional field-weakening method for induction motor drives based on model predictive control (MPC) is to take a no-load operation as the premise and adjust the flux reference in the cost function proportional to the inverse of the rotor speed, which leads to poor torque output. This paper presents a novel field-weakening method for IM drives based on MPC. Considering the induction motor field-weakening limiting conditions and according to the speed adaptive field-weakening strategy with a voltage closed-loop, the speed adaptive field-weakening controllers were designed to optimize the references of the excitation current and torque current. In the rotor field-orientation d–q coordinate system, the stator flux amplitude and torque reference values were optimized by the optimal distribution current. Then, according to the dead-beat control principle, they were converted into an equivalent stator flux vector reference. Moreover, the stator voltage vector reference can be obtained. For an induction motor fed by a three-level neutral point clamped (3L-NPC) inverter, the cost function was constructed by combining all the constraints, including the voltage vector, the neutral potential balance, and the switching frequency. In this way, the high-performance field-weakening operation for the induction motor based on a model predictive control can be realized. The simulation and experiment results show that the proposed method can increase the torque output by 22% in the field-weakening region; at the same time, the steady characteristics and the dynamic response performance can be maintained well.

To improve the voltage utilization rate of DC bus and reduce the voltage vector tracking error, a finite-control-set modulated model predictive control (FCS-M2PC) with overmodulation capacity for permanent magnet synchronous motor (PMSM) incorporating penalty function is proposed in this paper. Firstly, three modulation regions are determined according to the combined action of dead-beat control and model predictive control (MPC). Secondly, three, two and one voltage vectors are applied to linear modulation region (LMR), overmodulation region I (OMR-I) and overmodulation region II (OMR-II), respectively, to synthesize the reference voltage vector. Thirdly, to obtain better steady-state performance in the whole modulation region, the optimal vector dwell-times can be obtained from the uniform penalty function defined by a set of mode parameters to minimize the error between the current references and the current predictions, rather than applying a single voltage vector in the conventional finite-control-set model predictive control (FCS-MPC). The effectiveness and superiority of the proposed method are validated experimentally.

The dead-beat control problem for linear, periodic, discrete-time systems in presence of unmeasurable disturbances and external reference signals is considered. Using a polynomial method, a parameterization of all causal output feedback controllers solving the problem is provided. Index Terms--Dead-beat control, discrete time, linear systems, periodic systems.

In this paper, an open loop control scheme is developed in order to design a dead-beat control effort in the high order continuous-time systems. The dead-beat control is really a finite-time control law. In this method, the input signal has been manually selected such that the output signal becomes constant in a finite time. In the LTI systems, having known the step response, a control signal could be exactly selected such a way that the control objective would be met in a finite time. For this end, the dead-beat control problem is firstly investigated in a standard first order system. Then a similar problem is studied in the second order systems. Finally a general design framework would be developed to obtain a dead-beat control policy in the high order continuous-time systems. In the proposed method, the control design problem is deliberately converted into the solution of a linear matrix equation. Therefore the control signal would be determined by solving such an algebraic equation. The proposed procedure is applied in some continuous-time LTI systems. The simulation results are shown effectiveness of the suggested methods for designing of a finite-time control law in the continuous-time systems.

On the basis of the steady state analysis of the VIENNA rectifier, an improved direct synchronous decoupling method is used to model the current inner loop, and a small amount of power compensation is added to expand the working area to adapt to different degrees of unbalanced voltage, which can reduce the DC voltage ripple and reactive power DC component under unbalanced input condition. In addition, this paper adds dead-beat control to track the reference current and selects the best duty cycle to drive the gate. The control strategy effectively realizes DC side voltage ripple elimination and power factor correction. Simulation and experiment verify the correctness of the theoretical analysis and the feasibility of the control strategy.

We are concerned with the problem of fast and accurate tracking of currents in the general synchronous drive. The problem becomes complicated with decreasing available voltage, which is common in high-speed and field weakening regimes. The existing time-optimal controllers rely on a simplified model, ignoring stator resistance and differences in inductances. We derive a solution for the general model considering all parameters and show how the parameters affect the current trajectory. One simplifying assumption had to be made, but we show in simulation that it has a negligible impact on accuracy. The simplification allowed for the design of a feed-forward controller that has a low computational cost and can be easily implemented in realtime. We provide experimental validation of the controller on the developed IPMSM drive prototype of the rated power of 4.5 kW using conventional industrial DSP. The controller is compared to conventional PI and deadbeat solutions, demonstrating that the time-optimal controller can reach the required setpoint four times faster than the competitors at the field weakening regime of the drive. The proposed feed-forward control can be seen as a universal building block that can be combined with existing feedback controllers and observers and thus incorporated into existing control solutions.