Proportional-integral Control Method Research Articles

PENINGKATAN KINERJA PLTB MELALUI KENDALI FREKUENSI FUZZY LOGIC

This research explores the use of a Governor as a frequency control mechanism in a power generation system by implementing two control methods: Proportional-Integral (PI) Controller and Fuzzy Logic Controller (FLC). The objective of the study is to evaluate the dynamic frequency response of the system and compare the performance of both control methods against the permissible standard, which is within the range of 50±2% (49 Hz to 51 Hz). Through simulations of a power generation system, parameters were adjusted to achieve the target frequency, and both control methods were evaluated. The results indicate that both methods can maintain the frequency within the desired range. However, Fuzzy Logic Controller on the Governor produces a superior dynamic frequency response with a lower steady-state error percentage. The implementation of Fuzzy Logic Controller also demonstrates a faster time to reach steady state compared to the PI Controller method. This superiority suggests that FLC provides more adaptive and responsive control to load fluctuations, enhancing the efficiency and stability of the power generation system.This research provides deeper insights into optimizing frequency control on Governors, particularly through the use of Fuzzy Logic Controller. Consequently, the development of this technology has the potential to improve the performance and reliability of power generation systems, supporting the transition towards a more efficient and sustainable electric grid.

A speed loop control method of a laser tracing measurement control system

In a laser tracking control system, a motor drives the load to achieve continuous forward and reverse rotation speed control, and the magnitude of the load changes periodically during the motor rotation to realize tracking. Based on these characteristics, we propose an integral-separated improved variable universe fuzzy proportional-integral (PI) control method with torque feedforward compensation method in this study. The proposed method achieves the control performances of fast response, high steady-state accuracy, and strong anti-interference. The conventional fuzzy PI control method achieves good performance only in the unidirectional acceleration of a motor; therefore, we have improved its fuzzy rules, and designed a novel universe contraction–expansion factor. Additionally, a load torque observer is introduced to observe and compensate for the external load and to further improve the anti-interference performance of the tracking control system. The experimental results demonstrate that the integral-separated improved variable-universe fuzzy PI control method achieves better performance in the forward and reverse speed regulation processes of the motor. The overshoot is 92% less than that of the conventional PI control when the target speed is set to ±500 rpm. The Luenberger observer is introduced to observe and compensate for the load torque. After the stabilizing the speed and applying an external load of 0.2 N m to the motor, the maximum speed reduction is observed to be 59% less than that obtained using the conventional PI control. The improved PI control method satisfies the speed loop control requirements of the laser tracking control system and can improve the steady-state tracking accuracy and robustness of the system.

Design and Testing of Bidirectional DC-DC Converters for Emergency Lighting

Lighting systems are among the most energy-intensive systems in the home because they consume a lot of electricity. Nighttime blackouts are currently being caused by an urgent need for lighting systems, especially emergency lighting. PLN and the battery provide electrical energy for emergency lighting. DC-DC converters that use the bidirectional method regulate electrical energy sources. PLN bidirectional converters have two functions, namely buck mode and boost mode, which work whenever the primary source of PLN is out, the battery will automatically supply the lighting system. In this research, the bidirectional converter can switch from buck mode to boost mode depending on the voltage of the power supply When the power supply voltage is low, the converter will switch to buck mode to reduce the voltage, and when the power supply voltage is high, the converter will switch to boost mode to increase the voltage. This allows the battery to be used as a backup power source when the main source fails. A lamp load of 10 W is used in the boost mode of the discharging process. Analytical proportional integral control methods are used to control the charging and discharging processes.

Research on the adaptive proportional-integral control method of a direct-expansion photovoltaic-thermal heat pump system

An adaptive proportional-integral control method (APCM) of a direct expansion photovoltaic-thermal heat pump (DX-PVTHP) system is proposed. First, the APCM was adopted and the proportional and integral factors were determined by experiments. Then, a universal engineering model combined the 10-factor model and temperature prediction model is built. The initial electronic expansion valve (EEV) opening during start-up under different working conditions is predicted and the EEV opening under dramatic irradiance changes is corrected under the APCM. Multiple experiments were conducted to evaluate the effectiveness of the APCM and test the performance of DX-PVTHP system under the APCM. The results reveal that the stability of superheat improved under typical cloudy skies and the maximum overshoot value was 3.2 °C. The overshoot time percentage of superheat was 27.54% with a decrease of 36.12% relative to the conventional control method. Moreover, the average coefficient of performance and photoelectric conversion efficiency were 3.51 and 13.25% in household mode, and 3.16 and 13.78% in commercial mode. Furthermore, the comprehensive coefficient of heating and electricity generation (CHE) is proposed to evaluate the comprehensive coefficient of the DX-PVTHP system. The CHE of the system was obtained 34.92% in household mode and 32.83% in commercial mode.

밀폐형 공압회로 내 정밀압력제어를 위한 기계 구동식 가스 압력제어기의 제어특성 평가

In this work, precise gas pressure control based on a closed pneumatic circuit was achieved with a mechanically driven gas pressure controller (MDGPC), consisting of a variable-volume bellows chamber and linear actuator. The linear actuator was employed to change an axial dimension of the bellows chamber with the proportional (P) and proportional-integral (PI) controls for fast, stable, and precise pressure control of the gas inside the bellows chamber. The pressure control stability and resolution of the MDGPC were approximately 1.5 Pa and 10 Pa for the P control and 1 Pa and 5 Pa for the PI control, respectively. Despite the more stable and precise control characteristics of the PI control method, overshoots and undershoots observed during the set-point pressure changes and recoveries from pressure disturbances rendered it unsuitable for the MDGPC control method. In contrast, the MDGPC operated under the P control did not show any significant overshoots or undershoots when the set-point pressure abruptly changed or when the MDGPC was exposed to pressure disturbances. Therefore, it was concluded that a fast, precise, and stable gas pressure control in a closed manner was attainable with the MDGPC under the P control.

Energy Management and Control in Multiple Storage Energy Units (Battery-Supercapacitor) of Fuel Cell Electric Vehicles.

This paper presents a new approach of energy management for a fuel cell electric vehicle traction system. This system includes a supercapacitor, a traction battery of valve-regulated sealed lead-acid type, a high-performance permanent magnet traction system, and a power electronics converter. Special attention was placed on the coordination for managing the flow of energy from several sources to treat the concerns of prolonged electric vehicle mileage and battery lifetime for drivetrains of electric vehicles. Connection to a supercapacitor in parallel with the electric vehicle's battery affects electric vehicle battery lifetime and its range. The paper used a study case of an all-electric train, but the used methods can be applied on hybrid or electric train cases. Fuzzy logic control and proportional integral control methods were used to control the electric vehicle system. The results of these two control methods were examined and compared. The simulation results were compared between the proposed electric vehicle system and the traditional system to show the effectiveness of the proposed method. Comparison of waveforms was made with and without the supercapacitor. The proposed optimized energy management strategy could improve the overall performance of the hybrid system and reduce the power consumption.

Model-Free Control of Single-Phase Boost AC/DC Converters

Conventionally, the benchmark proportional-integral control method is implemented to realize power factor correction and output voltage regulation of single-phase ac/dc converters. However, the performance is deteriorated due to the influence of uncertainties and disturbances, e.g., periodic input voltage and load variation. Concerning this problem, this article proposes a model-free control (MFC) strategy of single-phase ac/dc converters. The MFC principle is revisited and a frequency response analysis is presented for the algebraic estimators of uncertainties and disturbances. Consequently, the closed-loop performance of MFC systems is allowed to be analyzed in frequency domain via classical linear control theory. Based on the theoretical results, the model-free current and voltage control systems are synthesized in detail to achieve control objectives of the converter. Simulation results demonstrate the performance of MFC systems in reference tracking and disturbance rejection. The feasibility and validity of the presented MFC strategy for single-phase boost ac/dc converters is also confirmed experimentally as compared to the benchmark scheme.

A PI Control Method with HGSO Parameter Regulator for Trajectory Planning of 9-DOF Redundant Manipulator.

In order to solve the tracking accuracy problem of the redundant manipulator, a PI control method with Henry gas solubility optimization parameter regulator (PI-HGSO) is proposed in this paper. This method consists of the controller and the parameter regulator. The characteristic is that the position deviation of a manipulator is equivalent to a specific function; namely, the proportional-integral (PI) controller is used to adjust the deviation input. The error can be better corrected by the processing of the PI controller so that the inverse kinematics solution of the minimum error can be realized. At the same time, the parameter selection of PI controllers has always been a difficulty in controller design. To address the problem, Henry gas solubility optimization (HGSO) is selected as a parameter regulator to optimize the parameters and obtain the optimal controller, thereby achieving high-precision trajectory tracking. Experiments on 9-DOF redundant manipulator show that our method achieves competitive tracking accuracy in contrast with others. Meanwhile, the efficiency and accuracy of the PI controller are greatly guaranteed by using HGSO to automatically optimize controller parameters instead of making approximate adjustments through infinite manual trial and error. Therefore, the feasibility and competitive superiority of PI-HGSO is fully proved in trajectory planning of redundant manipulators.

Robust PI-Type Output Feedback Control of Unknown Nonlinear Systems

The proportional-integral (PI) control method is long well-known because of its simplicity as well as effectiveness. Although the PI control method overwhelmingly dominates engineering applications, the issue of developing a general PI control for nonlinear systems remains open. This paper considers the PI control problem for a family of unknown nonlinear systems. A structurally simple and computationally inexpensive PI-type control approach with constant gains is provided to solve the problem, which maintains pre-assigned transient as well as steady-state performance and guarantees the global stability of closed-loop systems. The key to possessing such properties comes down to the transformation and modification of tracking errors. The effectiveness of the presented control approach is assessed via the experiment on a pneumatic artificial muscle, and the results corroborate the theoretical findings.

Optimal Tracking and Resonance Damping Design of Cascaded Modular Model Predictive Control for a Common-Mode Stabilized Grid-Tied $LCL$ Inverter

A cascaded modular model predictive control (MMPC) method is designed for a modified nonisolated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$LCL$</tex-math></inline-formula> grid-connected inverters to provide resonance damping, improved dynamic performance, and leakage current attenuation capabilities. The continuous control set model predictive control strategy is applied for the proposed method. The active damping function of the inner loop MMPC is analyzed in detail to illustrate the mechanism of improving the system dynamic performance. The cascaded MMPC method is compared with the conventional proportional-integral (PI) control methods with/without a notch filter to show the merits in resonance damping and dynamic response. The optimal control parameters design procedure is elucidated with the tuning mechanism of the MMPC weighing factor and PI gain. With the proposed optimal MMPC design method, the dynamic performance of rising time and overshoot are improved compared to the conventional PI control methods with/without the notch filter. The simulation and experimental results verified the proposed control design method.

High performance control method of electro-mechanical actuator based on active disturbance rejection control

Integrated electro-mechanical actuators (EMAs) are widely used in cooperative robots. Their control system has to be carefully designed to achieve a desirable performance. The proportional-integral (PI) control and the active disturbance rejection control (ADRC) are the two commonly used controllers. Compared with the PI, the ADRC shows better performance in terms of disturbance rejection, response speed and overshooting suppression. However, the ADRC utilises numerous parameters and the optimisation of these parameters is a challenge. In this study, the influence of the parameters of β01, β02, β03, β1, β2 on the ADRC performance is deeply analysed. Considering the two non-linear factors of permanent magnet synchronous motor and harmonic transmission in the EMA, a simulation model of the EMA was established. An improved swarm optimisation algorithm was employed to optimise the parameters of the ADRC. A second-order ADRC in speed and position modes was designed. The parameters of the ADRC in these modes were adjusted using improved particle swarm optimisation. ADRC was applied to the EMA field-oriented control system instead of cascade PI, and the simulation and experimental results were compared using the cascade PI control method. When the target speed is to 15 rpm, the speed fluctuation range of the ADRC is about ±0.3 rpm, which is smaller than that of the PI controller’s ±0.5 rpm. Compared with the cascade PI control, ADRC affords a faster response speed, greater robustness and stronger disturbance resistance in the steady-state operation process.

A Constant Current Control Method With Improved Dynamic Performance for CLLC Converters

The capacitor–inductor–inductor–capacitor ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CLLC</i> ) converter is a promising topology for bidirectional power conversion applications, such as hydrogen or battery energy storage systems and bidirectional pulsing current charging or heating for electric vehicle (EV) batteries. For these applications, high dynamic constant current control is required. In this article, a novel constant current control method with improved dynamic performance over the conventional proportional–integral (PI) method is proposed for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CLLC</i> converter. In constant current control, the charging and discharging process of the output capacitor determines the dynamic performance. A state trajectory model is proposed for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CLLC</i> converter and is employed to analyze the transient process in the resonant tank. Based on the analysis, a novel dead-band-based control method for the constant current control is proposed. The proposed method can directly and effectively control the charging and the discharging process of the output capacitor, which the conventional PI control method cannot do. As a result, the dynamic performance is improved. The correctness of the proposed state trajectory model, the state trajectory analysis, and the effectiveness of the proposed constant current control method are verified by experiments. Experimental results show that the response time of the proposed method is reduced by more than 50% compared with that of the conventional PI method, with no overshoot.

Model predictive based frequency control of power system incorporating air-conditioning loads with communication delay

The variability of renewable energy sources (RESs) introduces more frequency fluctuations, and the reserve capacity of generation side needs to be sharply enlarged to maintain frequency stability, which inevitably increases the cost. In this paper, massive inverter air conditioners (IACs) as flexible regulation resources are aggregated to provide capacity support in frequency regulation. This paper establishes the state-space dynamic model and then presents a coordinated optimal control strategy by using model predictive control (MPC). However, the communication delay during the control signal transmission to IACs is one of the main obstacles that degrades the system performance in frequency regulation. To handle this issue, a predictive compensation method (PCM) based on MPC is applied to the control loop of IACs to compensate for the communication delay. Moreover, the robustness of the proposed MPC method with PCM against variations of system delay and parameters in the frequency response process is investigated in comparison to the proportional–integral (PI) controller. The simulation results are conducted to validate the superiority of the proposed method to the PI control method in virtue of the dynamic response and the performance indices, which demonstrates faster response, robustness, fewer fluctuations.

Modeling, Analysis and Proportional Resonant and Proportional Integral Based Control Strategy for Single Phase Quasi-Z Source Inverters

This paper proposes a proportional resonant and proportional integral based control strategy for single phase quasi-Z-source inverters (qZSIs) which is able to operate in buck and boost modes. Switching signals of the qZS inverters can be generalized as shoot through and non-shoot through states. The dc-link voltage of the qZSIs can be controlled by generating proper shoot through signals. The control strategy for qZSIs should be able to control both dc and ac-sides at the same time. First, the average state&#x2013;space model of qZSI is obtained for closed loop control in this paper. Thereafter, the proportional resonant control is designed to achieve ac-side voltage control. Also, voltage control of dc-side capacitor is achieved by using proportional integral control method. Finally, the switching signals are obtained by applying the control outputs to modulation strategy. Experimental results are presented to demonstrate the effectiveness of the control method. The results verify that the proposed control strategy successfully regulates both dc and ac-side control variables.

Control of the rated production power of DFIG-wind turbine using adaptive PSO and PI conventional controllers

Production of rated power and protection of generator and power converter from an overload are necessary. Therefore, measuring the accurate value of the pitch angle of the doubly fed induction generator (DFIG) wind turbine is essential. An assessment study between the adaptive particle swarm optimisation (PSO) technique and conventional proportional integral (PI) controller of the pitch control system in limiting the electrical output power at the rated value of DFIG is introduced in this study. Pitch control with PSO is designed by solving the nonlinear equation of pitch angle at each wind speed higher than rated wind speed. The PI controller gains of the pitch system are evaluated to keep the power limited at rated value. Accuracy in measuring pitch angle is essential because a small difference in pitch angle value results in an overload on the generator. The performance of each parameter of DFIG with a detailed analysis is studied. The simulation shows that the pitch control system with PSO technique gives better results in regulating the DFIG output power compared to PI controller method under wind speed variation.

Back Electro Motive Force Estimation Method for Cascade Proportional Integral Control in Permanent Magnet Synchronous Motors

A cascade proportional integral control method with back-electro motive force compensation has been widely used for permanent magnet synchronous motors. In the permanent magnet synchronous motor control, it is important to accurately know the back-electro motive force constant for torque generation as well as back-electro motive force compensation. In this study, a real-time back-electro motive force constant estimation algorithm is developed to improve the velocity tracking control performance. The proposed method consists of a proportional integral controller and a back-electro motive force constant estimator. The proportional integral controller is designed to reduce the velocity tracking error. The back-electro motive force constant estimator is designed to estimate the back-electro motive force constant. It was verified that the estimated back-electro motive force constant converges to the actual back-electro motive force constant. The estimated back-electro motive force constant is applied to the cascade proportional integral controller. To verify the effectiveness of the proposed method, the performance of the proposed method is validated experimentally.

Dynamic parking charge–perimeter control coupled method for a congested road network based on the aggregation degree characteristics of parking generation distribution

Homogeneous traffic density is the precondition of macroscopic fundamental diagrams (MFDs) that exist in a regional road network. However, traffic density may be transformed by the effects of traffic flow transmission and parking generation in a dynamic system. Once the homogeneous and uniform traffic density is changed, the shape of the MFD curve is likely affected, and thus, the output efficiency of the road network decreases.Based on the existing research of the aggregation evaluation model of parking generation in a regional road network, the study analyses the relationship between the variation in parking generation aggregation and the variation ratio in the trip completion flow of the network through further analysis. On this basis, a dynamic parking charge–perimeter control coupled (DPCPCC) method in a macro road network is proposed to balance the traffic flow density in a dynamically congested sub-region that exists in multiple public parking lots and to improve the efficiency of traffic flow for the entire road network. Furthermore, the method optimizes the entire parking charge rate of each MFD sub-region, aiming for the lowest generalized cost, reduces the delay time of the road network by adjusting the perimeter control rate, and changes the traffic aggregation index by dynamic charging strategies to improve the congested sub-region outflow efficiency. Finally, the regional road network in the Binhu New District of Hefei is taken as an example, and three control scenarios consisting of the DPCPCC method, the static parking charge–perimeter control coupled (SPCPCC) method, and the proportional–integral (PI) method are analysed and compared.According to the analysis of the relationship between the parking generation aggregation index and MFD changes and the application of this relationship to verify the regional road network dynamic charging model, the results reveal that the DPCPCC method can reduce the marginal social cost and improve the operation efficiency of the road network compared with the SPCPCC and PI control methods.

Hybrid force/position control in workspace of robotic manipulator in uncertain environments based on adaptive fuzzy control

In this study, a novel hybrid force/position controller in workspace of robotic manipulator based on adaptive fuzzy control is developed to improve the controlling performance of force and position in contact with uncertain environments. The dynamic model of the robotic manipulator in joint space is converted to a dynamic model in workspace, which is consisted of the model of position-controlled subsystem and model of force-controlled subsystem. Furthermore, in the position-controlled subsystem, an adaptive fuzzy computed torque control is proposed by considering adaptive fuzzy control and conventional computed torque control (AFCTC), for compensating deviations caused by the presence of structured uncertainty and unstructured uncertainty. In the force-controlled subsystem, a fuzzy proportional integral control method (FPI) is proposed by fuzzy logic and conventional proportional integral method to improve the control performance. The asymptotic stability of the developed controller is proved by Lyapunov theorem. The simulation results show the preferable performance of the proposed controller (AFCTC-FPI) by comparison with adaptive fuzzy sliding mode control (AFSMC), adaptive network-based fuzzy inference system with proportion differential and integral (ANFIS-PD+I), computed torque control-proportion integral (CTC-PI), fuzzy proportional integral derivative (FPID), and proportional integral derivative (PID) in uncertain environments. Furthermore, in the experimental study, average position error with AFCTC-FPI is decreased by 87.14 % than that with PID, meanwhile, range of interaction force with AFCTC-FPI is reduced by 70.31% than that with PID. In summary, the experimental results also show the superior control accuracy of the proposed controller in real environment.

Mountain Rescue Mobile Platform based on Anti-saturation Strategy Proportional Integral Control

Rugged terrain and inconvenient transportation in the rural areas of southwest China, lead to difficulties in transporting power equipments such as electric poles, transmission lines and small transformers in time of power grid upgrading and emergencies. In particular, when there is no road in the last few kilometers, the transportation relies totally on manpower. In this paper, the dynamics of the power equipment mobile platform is analyzed, and then its stability is analyzed using the proportional-integral control method with anti-saturation strategy. Combined with the control rate characteristics and anti-saturation strategy, the stable operation conditions of the mobile platform are obtained, making it possible for the platform to drive in mountains, hills and farmlands. This creates an efficient mechanical operation mode under no-road conditions during construction.

Active disturbance rejection control of nonlinear SISO Lagrangian systems via endogenous injections and exogenous feedback for trajectory tracking

This article deals with a linear classical approach for the robust output reference trajectory tracking control of nonlinear SISO Lagrangian systems with a controllable (flat) tangent linearization around an operating equilibrium point. An endogenous injections and exogenous feedback (EIEF) approach is proposed, which is naturally equivalent to the generalized proportional integral control method and to a robust classical compensation network. It is shown that the EIEF controller is also equivalent, within a frequency domain setting demanding respect for the separation principle, to the reduced order observer based active disturbance rejection control approach. The proposed linear control approach is robust with respect to total disturbances and, thus, it is effective for the linear control of the nonlinear Lagrangian system. An illustrative nonlinear rotary crane Lagrangian system example, which is non-feedback linearizable, is presented along with digital computer simulations.