In order to reach a compromise between fast response control and torques matching control in double turboshaft engines,research on nonlinear model predictive control for turboshaft engines based on double engines torq...In order to reach a compromise between fast response control and torques matching control in double turboshaft engines,research on nonlinear model predictive control for turboshaft engines based on double engines torques matching is conducted.Meanwhile,a Nonlinear Model Predictive Control(NMPC)method is proposed,which combines the control index of the power turbine speed with torques matching of double engines creatively.In addition to the control index,the difference of output torques between each engine is also incorporated in the objective function as a penalty term to ensure constant speed control and short torques matching time.Simulation results demonstrate that relative to unilateral torques matching,the settling time of the bidirectional matching method can be reduced by nearly 30.8%.Nevertheless,compared with the bidirectional torques matching method under the cascade PID controller,the NMPC method can decrease the overshoot of the power turbine speed by 65%and reduce the matching time by 15.5%synchronously.Besides fast response control of turboshaft engines,fast torques matching control of double engines is accomplished as well.展开更多
This paper studied a supervisory control system for a hybrid off-highway electric vehicle under the chargesustaining(CS)condition.A new predictive double Q-learning with backup models(PDQL)scheme is proposed to optimi...This paper studied a supervisory control system for a hybrid off-highway electric vehicle under the chargesustaining(CS)condition.A new predictive double Q-learning with backup models(PDQL)scheme is proposed to optimize the engine fuel in real-world driving and improve energy efficiency with a faster and more robust learning process.Unlike the existing“model-free”methods,which solely follow on-policy and off-policy to update knowledge bases(Q-tables),the PDQL is developed with the capability to merge both on-policy and off-policy learning by introducing a backup model(Q-table).Experimental evaluations are conducted based on software-in-the-loop(SiL)and hardware-in-the-loop(HiL)test platforms based on real-time modelling of the studied vehicle.Compared to the standard double Q-learning(SDQL),the PDQL only needs half of the learning iterations to achieve better energy efficiency than the SDQL at the end learning process.In the SiL under 35 rounds of learning,the results show that the PDQL can improve the vehicle energy efficiency by 1.75%higher than SDQL.By implementing the PDQL in HiL under four predefined real-world conditions,the PDQL can robustly save more than 5.03%energy than the SDQL scheme.展开更多
A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to...A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to achieve high-precision control,two-phase current sensors are necessary for successful implementation of MPTC.For this purpose,two ESOs are used to estimate q-axis current and stator resistance respectively,and then based on this,d-axis current is estimated.Moreover,to reduce torque and flux ripple and to improve the performance of the torque and speed,MPTC strategy is designed.The simulation results validate the feasibility and effectiveness of the proposed scheme.展开更多
Denurcioslu et al. presented a method named continuous-time general-ized predictive control(CGPC) in 1991, which is obtained on the basis of the mini-mization of a quadratic cost function. However, In engineering prac...Denurcioslu et al. presented a method named continuous-time general-ized predictive control(CGPC) in 1991, which is obtained on the basis of the mini-mization of a quadratic cost function. However, In engineering practice, the behav-ior of a control system is generally evaluated by observing its dynamic response con-cerned mainly with the clused-loup poles uf the system. A CGPC algorithm withclosed-loop pole-placement is propused in this paper which advances the results byDemircioglu et al.展开更多
To reach an acceptable controller strategy and tuning it is important to state what is considered “good”. To do so one can set up a closed-loop specification or formulate an optimal control problem. It is an interes...To reach an acceptable controller strategy and tuning it is important to state what is considered “good”. To do so one can set up a closed-loop specification or formulate an optimal control problem. It is an interesting question, if the two can be equivalent or not. In this article two controller strategies, model predictive control (MPC) and constrained direct inversion (CDI) are compared in controlling the model of a pilot-scale water heater. Simulation experiments show that the two methods are similar, if the manipulator movements are not punished much in MPC, and they act practically the same when a filtered reference signal is applied. Even if the same model is used, it is still important to choose tuning parameters appropriately to achieve similar results in both strategies. CDI uses an analytic approach, while MPC uses numeric optimization, thus CDI is more computationally efficient, and can be used either as a standalone controller or to supplement numeric optimization.展开更多
Design of general multivariable process controllers is an attractive and practical alternative to optimizing design by evolutionary algorithms (EAs) since it can be formulated as an optimization problem. A closed-loop...Design of general multivariable process controllers is an attractive and practical alternative to optimizing design by evolutionary algorithms (EAs) since it can be formulated as an optimization problem. A closed-loop particle swarm optimization (CLPSO) algorithm is proposed by mapping PSO elements into the closed-loop system based on control theories. At each time step, a proportional integral (PI) controller is used to calculate an updated inertia weight for each particle in swarms from its last fitness. With this modification, limitations caused by a uniform inertia weight for the whole population are avoided, and the particles have enough diversity. After the effectiveness, efficiency and robustness are tested by benchmark functions, CLPSO is applied to design a multivariable proportional-integral-derivative (PID) controller for a solvent dehydration tower in a chemical plant and has improved its performances.展开更多
Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the s...Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the speed range under finite DC-bus voltage,extensive research on field weakening(FW)control strategies has been conducted.This paper summarizes the major FW control strategies of PMSMs,which are categorized into calculation-based methods,voltage closed-loop control methods,and model predictive control related methods.The existing strategies are analyzed and compared according to performance,robustness,and execution difficulty,which can facilitate the implementation of FW control.展开更多
Digital pulsed metal inert gas welding machine with double closed-loop control mode is designed and implemented. It realizes precision control for real time energy and demonstrates the flexibility of digital control. ...Digital pulsed metal inert gas welding machine with double closed-loop control mode is designed and implemented. It realizes precision control for real time energy and demonstrates the flexibility of digital control. Test results of design prototype show that the designed control strategy can effectively adapt to the change of arc length and achieve ideal droplet transfer via one drop per pulse mode. Thus the welding process is stable and the weld bead is good.展开更多
A novel real-time predictive control strategy is proposed for path following(PF)and vehicle stability of autonomous electric vehicles under extreme drive conditions.The investigated vehicle configuration is a distribu...A novel real-time predictive control strategy is proposed for path following(PF)and vehicle stability of autonomous electric vehicles under extreme drive conditions.The investigated vehicle configuration is a distributed drive electric vehicle,which allows to independently control the torques of each in-wheel motor(IWM)for superior stability,but bringing control com-plexities.The control-oriented model is established by the Magic Formula tire function and the single-track vehicle model.For PF and direct yaw moment control,the nonlinear model predictive control(NMPC)strategy is developed to minimize PF tracking error and stabilize vehicle,outputting front tires’lateral force and external yaw moment.To mitigate the calcu-lation burdens,the continuation/general minimal residual algorithm is proposed for real-time optimization in NMPC.The relaxation function method is adopted to handle the inequality constraints.To prevent vehicle instability and improve steering capacity,the lateral velocity differential of the vehicle is considered in phase plane analysis,and the novel stable bounds of lateral forces are developed and online applied in the proposed NMPC controller.Additionally,the Lyapunov-based constraint is proposed to guarantee the closed-loop stability for the PF issue,and sufficient conditions regarding recursive feasibility and closed-loop stability are provided analytically.The target lateral force is transformed as front steering angle command by the inversive tire model,and the external yaw moment and total traction torque are distributed as the torque commands of IWMs by optimization.The validations prove the effectiveness of the proposed strategy in improved steering capacity,desirable PF effects,vehicle stabilization,and real-time applicability.展开更多
The traditional PI controller for a hybrid energy storage system(HESS)has certain drawbacks,such as difficult tuning of the controller parameters and the additional filters to allocate high-and low-frequency power flu...The traditional PI controller for a hybrid energy storage system(HESS)has certain drawbacks,such as difficult tuning of the controller parameters and the additional filters to allocate high-and low-frequency power fluctuations.This paper proposes a model predictive control(MPC)method to control three-level bidirectional DC/DC converters for grid-connections to a HESS in a DC microgrid.First,the mathematical model of a HESS consisting of a battery and ultra capacitor(UC)is established and the neutral point voltage imbalance of a three-level converter is solved by analyzing the operating modes of the converter.Secondly,for the control of the grid-connected converters,an MPC method is proposed for calculating steady-state reference values in the outer layer and the dynamic rolling optimization in the inner layer.The outer layer ensures the voltage regulation and establishes the current predictive model,while the inner layer,using the model predictive current control,makes the current follow the predictive value,thus reducing the system current ripple.This cascaded topology has two independent controllers and is free of filters to realize the high-and low-frequency power allocation for a HESS.Therefore,it allows two types of energy storage devices to independently regulate the voltage and realizes the power allocation of the battery and UC.Finally,simulation studies are conducted in PSCAD/EMTDC,and the effectiveness of the proposed HESS control strategy is verified in a case,such as a controller comparison and fault scenario.展开更多
基金co-supported by the National Natural Science Foundation of China(No.51576096)Qing Lan and 333 Project and Research Funds for Central Universities(No.NF2018003).
文摘In order to reach a compromise between fast response control and torques matching control in double turboshaft engines,research on nonlinear model predictive control for turboshaft engines based on double engines torques matching is conducted.Meanwhile,a Nonlinear Model Predictive Control(NMPC)method is proposed,which combines the control index of the power turbine speed with torques matching of double engines creatively.In addition to the control index,the difference of output torques between each engine is also incorporated in the objective function as a penalty term to ensure constant speed control and short torques matching time.Simulation results demonstrate that relative to unilateral torques matching,the settling time of the bidirectional matching method can be reduced by nearly 30.8%.Nevertheless,compared with the bidirectional torques matching method under the cascade PID controller,the NMPC method can decrease the overshoot of the power turbine speed by 65%and reduce the matching time by 15.5%synchronously.Besides fast response control of turboshaft engines,fast torques matching control of double engines is accomplished as well.
基金Project(KF2029)supported by the State Key Laboratory of Automotive Safety and Energy(Tsinghua University),ChinaProject(102253)supported partially by the Innovate UK。
文摘This paper studied a supervisory control system for a hybrid off-highway electric vehicle under the chargesustaining(CS)condition.A new predictive double Q-learning with backup models(PDQL)scheme is proposed to optimize the engine fuel in real-world driving and improve energy efficiency with a faster and more robust learning process.Unlike the existing“model-free”methods,which solely follow on-policy and off-policy to update knowledge bases(Q-tables),the PDQL is developed with the capability to merge both on-policy and off-policy learning by introducing a backup model(Q-table).Experimental evaluations are conducted based on software-in-the-loop(SiL)and hardware-in-the-loop(HiL)test platforms based on real-time modelling of the studied vehicle.Compared to the standard double Q-learning(SDQL),the PDQL only needs half of the learning iterations to achieve better energy efficiency than the SDQL at the end learning process.In the SiL under 35 rounds of learning,the results show that the PDQL can improve the vehicle energy efficiency by 1.75%higher than SDQL.By implementing the PDQL in HiL under four predefined real-world conditions,the PDQL can robustly save more than 5.03%energy than the SDQL scheme.
基金National Natural Science Foundation of China(No.61463025)Opening Foundation of Key Laboratory of Opto-technology and Intelligent Control(Lanzhou Jiaotong University),Ministry of Education(No.KFKT2018-8)
文摘A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to achieve high-precision control,two-phase current sensors are necessary for successful implementation of MPTC.For this purpose,two ESOs are used to estimate q-axis current and stator resistance respectively,and then based on this,d-axis current is estimated.Moreover,to reduce torque and flux ripple and to improve the performance of the torque and speed,MPTC strategy is designed.The simulation results validate the feasibility and effectiveness of the proposed scheme.
文摘Denurcioslu et al. presented a method named continuous-time general-ized predictive control(CGPC) in 1991, which is obtained on the basis of the mini-mization of a quadratic cost function. However, In engineering practice, the behav-ior of a control system is generally evaluated by observing its dynamic response con-cerned mainly with the clused-loup poles uf the system. A CGPC algorithm withclosed-loop pole-placement is propused in this paper which advances the results byDemircioglu et al.
文摘To reach an acceptable controller strategy and tuning it is important to state what is considered “good”. To do so one can set up a closed-loop specification or formulate an optimal control problem. It is an interesting question, if the two can be equivalent or not. In this article two controller strategies, model predictive control (MPC) and constrained direct inversion (CDI) are compared in controlling the model of a pilot-scale water heater. Simulation experiments show that the two methods are similar, if the manipulator movements are not punished much in MPC, and they act practically the same when a filtered reference signal is applied. Even if the same model is used, it is still important to choose tuning parameters appropriately to achieve similar results in both strategies. CDI uses an analytic approach, while MPC uses numeric optimization, thus CDI is more computationally efficient, and can be used either as a standalone controller or to supplement numeric optimization.
文摘Design of general multivariable process controllers is an attractive and practical alternative to optimizing design by evolutionary algorithms (EAs) since it can be formulated as an optimization problem. A closed-loop particle swarm optimization (CLPSO) algorithm is proposed by mapping PSO elements into the closed-loop system based on control theories. At each time step, a proportional integral (PI) controller is used to calculate an updated inertia weight for each particle in swarms from its last fitness. With this modification, limitations caused by a uniform inertia weight for the whole population are avoided, and the particles have enough diversity. After the effectiveness, efficiency and robustness are tested by benchmark functions, CLPSO is applied to design a multivariable proportional-integral-derivative (PID) controller for a solvent dehydration tower in a chemical plant and has improved its performances.
基金supported by the Research Fund for the National Natural Science Foundation of China(52125701).
文摘Due to high power density,high efficiency,and accurate control performance,permanent magnet synchronous motors(PMSMs)have been widely adopted in equipment manufacturing and energy transformation fields.To expand the speed range under finite DC-bus voltage,extensive research on field weakening(FW)control strategies has been conducted.This paper summarizes the major FW control strategies of PMSMs,which are categorized into calculation-based methods,voltage closed-loop control methods,and model predictive control related methods.The existing strategies are analyzed and compared according to performance,robustness,and execution difficulty,which can facilitate the implementation of FW control.
基金Supported by National Natural Science Foundation of China （ Grant No. 50875088）.
文摘Digital pulsed metal inert gas welding machine with double closed-loop control mode is designed and implemented. It realizes precision control for real time energy and demonstrates the flexibility of digital control. Test results of design prototype show that the designed control strategy can effectively adapt to the change of arc length and achieve ideal droplet transfer via one drop per pulse mode. Thus the welding process is stable and the weld bead is good.
基金supported by the Natural Science Foundation of Beijing(Grant No.3212013)by the National Natural Science Foundation of China(Grant No.51805030)in part by the National Natural Science Foundation of China(Grant No.51775039).
文摘A novel real-time predictive control strategy is proposed for path following(PF)and vehicle stability of autonomous electric vehicles under extreme drive conditions.The investigated vehicle configuration is a distributed drive electric vehicle,which allows to independently control the torques of each in-wheel motor(IWM)for superior stability,but bringing control com-plexities.The control-oriented model is established by the Magic Formula tire function and the single-track vehicle model.For PF and direct yaw moment control,the nonlinear model predictive control(NMPC)strategy is developed to minimize PF tracking error and stabilize vehicle,outputting front tires’lateral force and external yaw moment.To mitigate the calcu-lation burdens,the continuation/general minimal residual algorithm is proposed for real-time optimization in NMPC.The relaxation function method is adopted to handle the inequality constraints.To prevent vehicle instability and improve steering capacity,the lateral velocity differential of the vehicle is considered in phase plane analysis,and the novel stable bounds of lateral forces are developed and online applied in the proposed NMPC controller.Additionally,the Lyapunov-based constraint is proposed to guarantee the closed-loop stability for the PF issue,and sufficient conditions regarding recursive feasibility and closed-loop stability are provided analytically.The target lateral force is transformed as front steering angle command by the inversive tire model,and the external yaw moment and total traction torque are distributed as the torque commands of IWMs by optimization.The validations prove the effectiveness of the proposed strategy in improved steering capacity,desirable PF effects,vehicle stabilization,and real-time applicability.
基金supported in part by the State Grid Corporation of China under Grant No.521500190017.
文摘The traditional PI controller for a hybrid energy storage system(HESS)has certain drawbacks,such as difficult tuning of the controller parameters and the additional filters to allocate high-and low-frequency power fluctuations.This paper proposes a model predictive control(MPC)method to control three-level bidirectional DC/DC converters for grid-connections to a HESS in a DC microgrid.First,the mathematical model of a HESS consisting of a battery and ultra capacitor(UC)is established and the neutral point voltage imbalance of a three-level converter is solved by analyzing the operating modes of the converter.Secondly,for the control of the grid-connected converters,an MPC method is proposed for calculating steady-state reference values in the outer layer and the dynamic rolling optimization in the inner layer.The outer layer ensures the voltage regulation and establishes the current predictive model,while the inner layer,using the model predictive current control,makes the current follow the predictive value,thus reducing the system current ripple.This cascaded topology has two independent controllers and is free of filters to realize the high-and low-frequency power allocation for a HESS.Therefore,it allows two types of energy storage devices to independently regulate the voltage and realizes the power allocation of the battery and UC.Finally,simulation studies are conducted in PSCAD/EMTDC,and the effectiveness of the proposed HESS control strategy is verified in a case,such as a controller comparison and fault scenario.
