Deadbeat Current Control Research Articles

Adaptive Predictive Deadbeat Current Control of Single-Phase Multi-Tuned Shunt Hybrid Active Power Filters

This paper suggests an adaptive predictive deadbeat current control method for single-phase multi-tuned shunt hybrid active power filters (HAPFs) to improve the power quality of single-phase and three-phase four-wire utility grids. The HAPF structure eliminates the resonance between the passive power filter and the grid impedance. Furthermore, it can be integrated into passive filters to enhance their filtering performance. In this paper, a digital algorithm is proposed for managing the performance of each converter leg accurately. To do so, an exact model of the high-order system is developed, and the transfer function of the plant is calculated in continuous and discrete time domains. Then, a predictive deadbeat technique for HAPF current control is presented, which benefits from high accuracy, fast dynamics, and low sensitivity to system parameter mismatches. Extensive simulation and experimental tests are conducted and the results match well to confirm the success and appropriate performance of the overall system. Also, performance comparison with conventional solutions demonstrates the superiority of the suggested filtering technique.

Loss Modulated Deadbeat Control for Grid Connected Inverter System

Deadbeat controllers are commonly employed in grid connected inverter systems for their fast transient response. In this paper, a loss modulated deadbeat current control (DCC) is proposed for a grid connected inverter system. This control calculates the required modulation signal by considering the losses in the system at every switching cycle. The proposed method tracks the reference current with negligible error. The loss component used in the control method eliminates the effect of sensing and computational time delay and adapts to variation in system parameter. The proposed DCC is extended for deadbeat based direct power control (DDPC) without employing inner current control loop. Further, a modified DDPC is presented to eliminate the delay of one switching cycle which is inherently present for the grid current in DCC. The proposed control concepts are realized on a multi-source fed switched capacitor based multilevel inverter. The topology considered features more number of voltage levels with less component count, high gain, self capacitor charge balancing and increased source utilization. The steady-state and transient behaviour of the control methods are verified in simulation and experimental studies for a power rating of 500 W under various system conditions. The proposed algorithms are able to track the reference signals with fast transient response and negligible steady-state error.

Fault-tolerant control strategy of six-phase permanent magnet synchronous motor based on deadbeat current prediction.

The fault-tolerant control after phase loss is crucial in the studies of the six-phase permanent magnet synchronous motor (PMSM), and the one phase loss is the most frequent phase loss fault. To improve the system instability caused by nonlinear and time-varying perturbations of inductance parameters in a double-Y phase shifted 30° six-phase PMSM, an improved deadbeat predictive current fault-tolerant control (DPC-FTC) method is proposed in this study. The transformation matrix after single-phase open-phase is first reduced and reconstructed, and the reduced-dimensional voltage equation is derived. Based on this equation, the deadbeat current predictive control is then used to predict the expected voltage using the current feedback value and the reference value, so as to shorten the response time and improve the overall control effect. The voltage equation after parameter perturbation is rewritten, and the current discrete transfer function under constant expected voltage before and after parameter perturbation is calculated. Afterwards, to further improve the low stability of fault-tolerant control after phase loss, which is caused by the inductance parameter perturbation of the control system, the weight coefficient is introduced in order to enhance the deadbeat predictive current control so that it splits and optimizes the direct-quadrature axis current. The stability of the system is then analyzed. By changing the weight coefficient, the fault-tolerant control system has a wider stable working range. Finally, the simulation model and experimental platform are completed. The results show that the improved DPC-FTC method improves the permissible inductor parameter uptake range by a factor of 1/β, reduces the current static difference by 32.05% and 46.02% when the inductor parameter is mismatched by a factor of 2, reduces the current oscillation and effectively reduces the sensitivity of system stability to inductor parameter uptake.

Control of a transformerless static synchronous series compensator for unbalanced voltage compensation

AbstractThis paper explores a transformerless static synchronous series compensator (TL‐SSSC) for mitigating voltage distortion in a power distribution line with renewable generations. A novel deadbeat current control scheme with time delay compensation is proposed which models the a‐b‐c three phase line with TL‐SSSC plus its LC filters and predicts the compensating voltages to be injected by the TL‐SSSC. Without resolving measured voltages and currents into positive and negative sequences, the scheme is computationally efficient and effective in mitigating voltage distortion due to faults occurring at different locations along the distribution line. It also eliminates the problem of inaccurate compensation voltage caused by inverter filter choking voltage drop. The paper also analyses the power controllable ranges for a TL‐SSSC under different unbalanced voltage ratios. The proposed TL‐SSSC and control scheme is validated using Typhoon Hardware‐In –Loop (HIL) device. Experimental results on mitigation unbalanced voltages of a 11kV transmission line confirm the effectiveness and high performance.

Modulated Model-Predictive Integral Control Applied to a Synchronous Reluctance Motor Drive

This paper investigates an innovative modulation technique for a predictive control applied to a synchronous reluctance motor drive. The new formulation of the duty cycles, in both linear and overmodulation regions, relies on the identified flux-versus-current characteristics. Furthermore, integral terms have been introduced in the predictive control to achieve satisfactory reference tracking performance with zero steady-state error, even under model parameters mismatches. Low current ripple with smooth and fast dynamic responses are achievable at fixed switching frequency over the whole current operating range. Simulations and experimental evidence show the effectiveness of the proposed controller against standard controllers such as field-oriented current control and deadbeat current control, guaranteeing low current ripple, robustness against parameters variations, and fast dynamic performance.

Sliding-Mode-Based Deadbeat Predictive Current Control for PMSM Drives

Deadbeat predictive current control (DPCC) has become a research hotspot for permanent magnet synchronous motor (PMSM) drive systems due to its advantages of short dynamic response time and superior current tracking performance. However, the speed controller in traditional deadbeat current control usually consists of a linear proportional-integral (PI) controller, which cannot quickly limit uncertain disturbances from internal or external sources. Moreover, DPCC is more sensitive to model parameters. In order to reduce the parameter sensitivity of the DPCC method and improve the fast-limiting disturbance capability of the speed controller, a sliding-mode-based deadbeat predictive control method is presented in this article. First, the traditional DPCC is introduced; then, a variable-speed sliding-mode reaching law is designed, and a sliding-mode speed controller is developed using this law to improve the antidisturbance capability of the speed controller. Moreover, in order to suppress the negative impact of the parameter mismatches on the control performance, the parameter mismatches are considered when building the system model, and a sliding-mode-based deadbeat current controller based on the same sliding-mode reaching law as the speed controller is presented. Finally, the experimental results show that the proposed method has a better control performance.

Hybrid Prediction-Based Deadbeat Control for a High-Performance Shunt Active Power Filter

This paper proposes a hybrid current predictive deadbeat tracking control method to address the problem that a conventional deadbeat current tracking control has evolved into a deadbeat control in the digital implementation process. First, the reference current prediction link provides in advance the harmonic compensation reference current at two sampling periods by adopting adaptive forward linear prediction and repetitive prediction algorithms. It realizes the switching between the two current prediction algorithms by setting load dynamic occurrence discriminant conditions. Second, the inverter output current historical and harmonic compensation reference current data is used to predict the output current of the inverter. It can effectively predict the output current of the inverter while considering measurement noise suppression. The problems of the deadbeat control method are its strong mathematics model dependence and weak ability to resist high-frequency interference. Therefore, this study analyzes the robust stability of the control system under the uncertainties of the output filter inductor and equivalent resistance parameters of the active power filter and the measurement noise transmission in the system. Finally, the simulation and experimental results indicate that the proposed method based on hybrid current prediction has a high steady-state compensation accuracy and a fast dynamic response speed under steady-state and load mutation conditions. Thus, the proposed method can still effectively compensate the harmonic current under the condition of uncertain output filter inductor and its equivalent resistance parameters.

Investigation on Multisampling Deadbeat Current Control With Time-Delay Compensation in Grid-Connected Inverter

The control of voltage source converters (VSCs) is now implemented on digital microprocessors. This digitalization has the drawback of time delay in the control loop. The goal of this research work was to investigate improvements that can be obtained from the combination of model-based and model-free time-delay compensation approaches. Deadbeat control (DBC) from model-based techniques and the method of moving the control variable’s sampling instants, or the pulse-width modulation (PWM) updating instants, from model-free time-delay compensation techniques, were put together as the proposed new method of time-delay compensation in this study. These controllers were thoroughly examined in terms of control algorithm design, system stability analysis, and sensitivity analysis of plant parameter perturbations. In addition, thorough Simulink-based computer simulations were conducted in this work to assess the performance of each controller. The proposed method compensated about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$80~\mu \text{s}$ </tex-math></inline-formula> as compared with the time delay compensated by the conventional single-sampling method. This research work was limited to simulations only; hence, conducting experiments to further validate this research work could be a direction for further research.

Dynamic Enhancement for Dual Active Bridge Converter with a Deadbeat Current Controller.

This paper investigates the deadbeat current controllers for isolated bidirectional dual-active-bridge dc-dc converter (IBDC), including the peak current mode (PCM) and middle current mode (MCM). The controller uses an enhanced single phase shift (ESPS) modulation method by exploiting pulse width as an extra control variable in addition to phase shift ratio. The control variables for PCM controllers are derived in detail and the two different current controllers are compared. A double-closed-loop control method is then employed, which could directly control the high-frequency inductor current and eliminate the transient DC current bias of the transformer. Furthermore, load feedforward was introduced to further enhance the dynamic of the converter. With the proposed control method, the settling time could be reduced within several PWM cycles during load disturbance without transient DC current bias. A 5 kW IBDC converter prototype was built and the settling time of 6 PWM cycles during load change with voltage regulation mode was achieved, which verifies the superior dynamic performance of the control method.

Improved Flux Weakening Control Strategy for Five-Phase PMSM Considering Harmonic Voltage Vectors

This article proposes a novel flux weakening scheme for five-phase PMSM with active harmonic currents injection. The conventional flux weakening control schemes applied in the five-phase PMSM do not consider the voltage limit drop in the fundamental subspace due to the harmonic current controller. Thus, the derivation between the reference current trajectory and actual current trajectory would cause the current distortion when applying deadbeat current controller (DBCC). This article analyses the precise voltage limit circles considering the voltage drop caused by the resistance and harmonic currents control at first. Then, a feed-forward flux weakening control algorithm is designed to optimize the current trajectory online. The gradient descent method is used to ensure the converge speed and stability of the optimized current trajectory. Thirdly, the peak value of phase currents would be clipped by the harmonic currents to prevent the inverter current limit, where a new non-linear harmonic current controller is designed to precisely control the harmonic currents. Finally, the DBCC and modified SVPWM technology are utilized to generate the duty cycle. The proposed improved flux weakening control strategy is successfully implemented in an interior five-phase PMSM, and the performance demonstrate the effectiveness of this strategy.

Hybrid Active Power Filter for Power Quality Improvement

A Deadbeat current controller for an LC-coupling hybrid active power filter is proposed, which can track with the reference compensation current with low steady- state error and fast dynamic response. Moreover, it can lead Hybrid Active power Filter to be operating at a fixed switching frequency with low output current ripples, thus reducing the size of the filtering circuit. The stability issue and parameter design of the proposed deadbeat current controller are analyzed and discussed. Finally, the compensating performance of the deadbeat current controller for the Hybrid Active Power Filter (LC-HAPF) is verified by simulation compared with the conventional hysteresis bandwidth modulation control, the proportional-integral (PI) control, and the proportional multi-resonant control for the LC-HAPF, which shows its effectiveness and superior compensating performances.

Generic predictive model calibration for PMSMs with different topologies

The main difficulty in designing predictive controllers for permanent magnet motors with different topologies is the control of the additional current subspaces. The frequency of current components in these additional subspaces (harmonic subspaces and zero-sequence loop/subspaces) is several times the fundamental current frequency. Moreover, the inner voltage source would vary with operation conditions, and there are also different views about the causes of inner voltage sources. This paper analyses the inner voltage sources in these additional current subspaces for permanent magnet motors with different drive topologies using simulation and experiment. Based on the results of the simulations and experiments, we analyze the sources and characteristics of the inner voltage sources and provide a predictive model calibration method for the components in these additional subspaces. Finally, the deadbeat current control scheme based on calibrated look-up table is designed and verified.

Deadbeat two-vector model predictive current control for open-winding primary permanent-magnet linear motor

The structure of open-winding motor fed by the dual-inverter can increase the winding terminal voltage of the primary permanent-magnet linear motor (PPMLM). So, it is an effective method to improve the thrust performance of the PPMLM. Based on the detailed derivation of the mathematical model of the open-winding PPMLM and the in-depth analysis of the space voltage vector distribution characteristics of the dual-inverter, a deadbeat two-vector model predictive current control (MPCC) model is proposed in this paper. First, the optimal vector of the inverter 1 is determined by judging the position of the large sector. Second, two optimal vectors of the inverter 2 is determined by judging the position of the small sector. Finally, the duty cycle of the two optimal vectors of the inverter 2 is calculated to realize the proposed deadbeat two-vector MPCC algorithm. Compared with the traditional model predictive torque control (MPTC) and MPCC strategies, the proposed algorithm has the advantages of lower current harmonics (lower 34 % and 44 % under rated conditions, respectively) and better thrust performance (higher 77 % and 61 % under rated conditions, respectively) as well as lower computational complexity. Simulation and experimental results show that the proposed two-vector MPCC has good steady-state and dynamic performances, which can reduce the current harmonics and thrust ripple, and thus improve the motor drive performance compared with the traditional method.

A Wide-Range High-Voltage-Gain Bidirectional DC–DC Converter for V2G and G2V Hybrid EV Charger

This article proposes a new wide-range bidirectional dc–dc converter that has an improved voltage gain transfer ratio for use in electric vehicle (EV) applications. The converter preserves the common electrical ground between input and output terminals, and presents a low-voltage stress of switches, high utilization factor, and high efficiency. The proposed EV charger performance is evaluated for a bidirectional power flow in grid-connected vehicle-to-grid (V2G) and grid-to-vehicle (G2V) modes. The converter uses a dead-beat current controller in the dc–dc and dc–ac stages, which has a smooth, accurate, and fast response. Finally, experimental results for a 500 W, 40–200 V prototype are provided under a bidirectional power flow in a closed-loop system in the presence of the proposed dead-beat controllers. The obtained results substantiate the theoretical analysis and the applicability of this structure. The converter exhibits the capability for EV battery charging/discharging and demonstrates a peak efficiency of 97.2% and 96.8% in the step-down and step-up modes of operation, respectively.

A Deadbeat Current and Flux Vector Control for IPMSM Drive with High Dynamic Performance

In this paper, a new deadbeat stator current and flux linkage vector control (DB-CFVC) scheme for interior permanent magnet synchronous machines (IPMSM) is proposed. The control structure is simplified by implementing the proposed flux linkage vector control method in the α-β stationary coordinate. Unlike conventional deadbeat methods, the dynamic performance of the proposed DB-CFVC can be enhanced while voltage command saturation and over output current are avoided. This is achieved with a “reinforced” phase angle reference of stator flux linkage vector by considering rotor speed error and maximum voltage to properly enhance the quality of the calculated flux phase angle command. By predicting stator flux linkage and current in the stationary coordinate, the deadbeat direct flux linkage vector control based on the one-step delay compensation strategy becomes straightforward and exhibits low sensitivity to motor parameters compared to conventional methods performed in the rotating frame. Then, by developing a practical and robust hybrid flux linkage observer, the proposed DB-CFVC method can work more reliably and effectively than conventional methods. Simulations and experiments are conducted in a drive system for an IPMSM to evaluate the effectiveness and reliability of the proposed method.

Research on Improved Current Predictive Control of Permanent Magnet Synchronous Motor

Aiming at the motion control problem in permanent magnet synchronous motor speed control system, an improved deadbeat current predictive control algorithm based on fuzzy PID control is proposed. In this algorithm, the traditional PID control uses fuzzy control to realize real-time parameter adjustment, it eliminates the overshoot of the system; The improved deadbeat current predictive control is adopted in the current loop, and the control output of the speed loop is taken as the input of the current loop. the output speed of the motor is adjusted, so feedback control is formed to obtain accurate and fast track performance. The simulation results show that the control algorithm is fast and robust under no-load and disturbance conditions, which verifies the feasibility and effectiveness of the algorithm.

Buck–Boost Common Ground Bridgeless PFC (CGBPFC) Rectifies With Positive/Negative Output

This article proposes new common ground bridgeless power factor correction rectifiers suitable for use in any application which requires a positive or negative dc power supply. The main advantage of the proposed rectifiers, compared to previous works, is the provision of the common ground between input and output, which eliminates electromagnetic interference (EMI) associated with high rates of change of voltage and consequently reduces the need for EMI common mode filtering. The converter also provides step-down and step-up operation, and facilitates positive or negative output voltages with a low number of semiconductor devices operating simultaneously. High power factor, acceptable grid-side current quality, and high efficiency are also achieved. Two variants are presented, referred to as type-I and type-II, which offer common ground positive and negative dc voltages, respectively. Closed-loop control of the converters is provided by a dead-beat current controller in the inner loop. Experimental results are presented for a 500-W prototype, operating from 220 and 110 Vrms input to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 48 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 200 Vdc output. The experimental results demonstrate the capability for step-down and step-up ac-to-dc power conversion with a peak efficiency of 96.8% and 96.6% in the positive and the negative outputs, respectively.

An Improved Deadbeat Current Controller of PMSM Based on Bilinear Discretization

Based on the bilinear discretization mathematical model of permanent magnet synchronous motor (PMSM), an improved incremental deadbeat current prediction control algorithm is proposed. Aiming at the system instability caused by the forward Euler discretization method, this paper combines the deadbeat current prediction control and the improved bilinear discretization method to improve the system stability. Further, the proposed controller considers the two-beat delay of a digital system to make the mathematical model more accurate. Moreover, the proposed bilinear discretization predictive current controller is not affected by the permanent magnet flux of the motor. Then, the system stability conditions of the proposed controller are analyzed. The simulation and experimental results verify the feasibility and effectiveness of the proposed method.

Deadbeat Current Control in Grid-Connected Inverters: A Comprehensive Discussion

Discrete-time dynamic systems demonstrate quite exciting possibilities from the perspective of control as compared with the continuous-time counterpart. Interesting properties of discrete-time dynamic systems include the possibility to algebraically determine previously unknown system parameters by simply measuring the present inputs and outputs of the system. Additionally, achieving a finite settling time with zero steady-state error is only achievable in discrete-time dynamic systems. Deadbeat current control (DBCC) has been used to achieve a finite settling time, especially in grid-connected inverter applications. However, there is no comprehensive study on reviewing or evaluating existing control approaches, to the authors’ best knowledge. This paper systematically examined the existing methods by paying attention to four key research issues: 1) research evidence indicating the adoption of DBCC in grid-connected inverter applications (GCIAs), 2) the types of deadbeat control approaches adopted in GCIAs, 3) the best approach in terms of stability especially regarding grid-impedance variation, and 4) the barriers that might prevent the wide adoption of DBCC in GCIAs. Finally, this paper presents a hypothesis based on the simulated results on which approach is superior at present to give readers a direction for further research classification on deadbeat control.

A Current Harmonic Suppression Method for PMSM Based on Harmonic Prediction Adaptive Notch Filter

The adaptive filters (ANF) have been commonly used in current harmonic suppression. However, the digital delay will narrow the stability region and its harmonic suppression performance will be deteriorated at high-speed region. To overcome this problem, this paper proposed two modified ANF. Combining with the deadbeat current (DBC) controller, the effect of digital delay on ANF is analyzed. A simple one step harmonic prediction method (OSPANF) is proposed to replace the traditional steepest gradient method (SGM). Based on the OSPANF, the current can be controlled stably in the high-speed area and the harmonic suppression effect is better than the traditional notch filter. Through bode diagram analysis, OSPANF will have a harmonic amplification peak near the set notch frequency, which may bring additional disturbances. Thus, a two steps prediction adaptive notch filter (TSPANF) is implemented. Through the Experimental results, it can be proved that the proposed TSPANF method has better harmonic suppression effect in the high-speed area than OSPANF and the stability region of the proposed two methods is larger than the traditional method.