In this paper, we proposed an output voltage stabilization of a DC-DC Zeta converter using hybrid control. We modeled the Zeta converter under continuous conduction mode operation. We derived a switching control law t...In this paper, we proposed an output voltage stabilization of a DC-DC Zeta converter using hybrid control. We modeled the Zeta converter under continuous conduction mode operation. We derived a switching control law that brings the output voltage to the desired level. Due to infinite switching occurring at the desired level, we enhanced the switching control law by allowing a sizeable output voltage ripple. We derived mathematical models that allow one to choose the desired switching frequency. In practice, the existence of the non-ideal properties of the Zeta converter results in steady-state output voltage error. By analyzing the power loss in the zeta converter, we proposed an improved switching control law that eliminates the steady-state output voltage error. The effectiveness of the proposed method is illustrated with simulation results.展开更多
To enhance power flow regulation in scenarios involving large-scale renewable energy transmission via high-voltage direct current(HVDC)links and multi-infeed DC systems in load-center regions,this paper proposes a hyb...To enhance power flow regulation in scenarios involving large-scale renewable energy transmission via high-voltage direct current(HVDC)links and multi-infeed DC systems in load-center regions,this paper proposes a hybrid modular multilevel converter–capacitor-commutated line-commutated converter(MMC-CLCC)HVDC transmission system and its corresponding control strategy.First,the system topology is constructed,and a submodule configuration method for the MMC—combining full-bridge submodules(FBSMs)and half-bridge submodules(HBSMs)—is proposed to enable direct power flow reversal.Second,a hierarchical control strategy is introduced,includingMMCvoltage control,CLCC current control,and a coordinationmechanism,along with the derivation of the hybrid system’s power flow reversal characteristics.Third,leveraging the CLCC’s fast current regulation and theMMC’s negative voltage control capability,a coordinated power flow reversal control strategy is developed.Finally,an 800 kV MMC-CLCC hybrid HVDC system is modeled in PSCAD/EMTDC to validate the power flow reversal performance under a high proportion of full-bridge submodule configuration.Results demonstrate that the proposed control strategy enables rapid(1-s transition)and smooth switching of bidirectional power flow without modifying the structure of primary equipment:the transient fluctuation ofDC voltage from the rated value(UdcN)to themaximumreverse voltage(-kUdcN)is less than 5%;the DC current strictly follows the preset characteristic curve with a deviation of≤3%;the active power reverses continuously,and the system maintains stable operation throughout the reversal process.展开更多
This paper presents an advanced control strategy for DC-DC buck converters utilizing Non-Minimal State Space (NMSS) representation combined with Proportional-Integral-Plus (PIP) control, optimized through Linear Quadr...This paper presents an advanced control strategy for DC-DC buck converters utilizing Non-Minimal State Space (NMSS) representation combined with Proportional-Integral-Plus (PIP) control, optimized through Linear Quadratic Regulator (LQR) design. The proposed approach leverages NMSS to eliminate the need for state observers, enhancing robustness against model mismatch and improving overall system performance. The PIP controller extends traditional PI control by incorporating additional dynamic feedback. Experimental results demonstrate that the NMSS-PIP-LQR controlled buck converter achieves excellent dynamic performance. The design procedure is fully documented, and microcontroller implementation issues are discussed.展开更多
By analyzing the output voltage ripple of a buck-boost converter with large equivalent series resistance（ESR） of output capacitor, one valley voltage-mode controller for buck-boost converter is proposed. Considering...By analyzing the output voltage ripple of a buck-boost converter with large equivalent series resistance（ESR） of output capacitor, one valley voltage-mode controller for buck-boost converter is proposed. Considering the fact that the increasing and decreasing slopes of the inductor current are assumed to be constant during each switching cycle, an especial sampleddata model of valley voltage-mode controlled buck-boost converter is established. Based on this model, the dynamical effect of an output-capacitor time-constant on the valley voltage-mode controlled buck-boost converter is revealed and analyzed via the bifurcation diagrams, the movements of eigenvalues, the Lyapunov exponent spectra, the boundary equations,and the operating-state regions. It is found that with gradual reduction of output-capacitor time-constant, the buck-boost converter in continuous conduction mode（CCM） shows the evolutive dynamic behavior from period-1 to period-2, period-4, period-8, chaos, and invalid state. The stability boundary and the invalidated boundary are derived theoretically by stability analysis, where the stable state of valley voltage-mode controlled buck-boost converter can enter into an unstable state, and the converter can shift from the operation region to a forbidden region. These results verified by time-domain waveforms and phase portraits of both simulation and experiment indicate that the sampled-data model is correct and the time constant of the output capacitor is a critical factor for valley voltage-mode controlled buck-boost converter, which has a significant effect on the dynamics as well as control stability.展开更多
Reaction flywheel is a significant actuator for satellites＇ attitude control. To improve output torque and rotational speed accuracy for reaction flywheel, this paper reviews the modeling and control approaches of DC...Reaction flywheel is a significant actuator for satellites＇ attitude control. To improve output torque and rotational speed accuracy for reaction flywheel, this paper reviews the modeling and control approaches of DC-DC converters and presents an application of the variable structure system theory with associated sliding regimes. Firstly, the topology of reaction flywheel is constructed. The small signal linearization process for a buck converter is illustrated. Then, based on the state averaging models and reaching qualification expressed by the Lee derivative, the general results of the sliding mode control （SMC） are analyzed. The analytical equivalent control laws for reaction flywheel are deduced detailedly by selecting various sliding surfaces at electromotion, energy consumption braking, reverse connection braking stages. Finally, numerical and experimental examples are presented for illustrative purposes. The results demonstrate that favorable agreement is established between the simulations and experiments. The proposed control strategy achieves preferable rotational speed regulation, strong rejection of modest disturbances, and high-precision output torque and rotational speed tracking abilities.展开更多
Based on the mechanism for the generation of chaos in a buck converter, a pole placement method is proposed and applied to controlling the chaos in a circuit. The control circuit is designed and tested. Numerical calc...Based on the mechanism for the generation of chaos in a buck converter, a pole placement method is proposed and applied to controlling the chaos in a circuit. The control circuit is designed and tested. Numerical calculation and circuit implementation demonstrate the validity of this chaos control method.展开更多
In this paper, a robust sliding mode controller for the control of dc-dc buck converter is designed and analyzed. Dynamic equations describing the buck converter are derived and sliding mode controller is designed. A ...In this paper, a robust sliding mode controller for the control of dc-dc buck converter is designed and analyzed. Dynamic equations describing the buck converter are derived and sliding mode controller is designed. A two-loop control is employed for a buck converter. The robustness of the sliding mode controlled buck converter system is tested for step load changes and input voltage variations. The theoretical predictions are validated by means of simulations. Matlab/Simulink is used for the simulations. The simulation results are presented. The buck converter is tested with operating point changes and parameter uncertainties. Fast dynamic response of the output voltage and robustness to load and input voltage variations are obtained.展开更多
This article studies a design and implementation of state-feedback control problem for dc-dc Positive Output Super Lift Luo (POSLL) converter by considering the line and load disturbances for needing desired power sou...This article studies a design and implementation of state-feedback control problem for dc-dc Positive Output Super Lift Luo (POSLL) converter by considering the line and load disturbances for needing desired power source for various portable electronic equipments like battery charger, hard disk drives, medical device, LED TV etc. The POSLL’s dynamic performance becomes non-linear in nature;the designed controller able to get superior dynamic performance given by load estimation is done by using an observer and by combining the state-feedback control with the load estimator, a controller which is explicitly developed with strong robustness using separation principle. An effectual stability analysis is exemplified to prove that by carefully selecting the state feedback control and observer gain matrix, the output voltage of the dc-dc POSLL converter tracks the desired value irrespective of the uncertainties. Extensive simulation is carried out using MATLAB/Simulink model. The result based on time domain analysis is done by using the controllers for various disturbances given to the converter.展开更多
This paper considers controlling and maximizing the absorbed power of wave energy converters for irregular waves. With respect to physical constraints of the system, a model predictive control is applied. Irregular wa...This paper considers controlling and maximizing the absorbed power of wave energy converters for irregular waves. With respect to physical constraints of the system, a model predictive control is applied. Irregular waves’ behavior is predicted by Kalman filter method. Owing to the great influence of controller parameters on the absorbed power, these parameters are optimized by imperialist competitive algorithm. The results illustrate the method’s efficiency in maximizing the extracted power in the presence of unknown excitation force which should be predicted by Kalman filter.展开更多
A discrete iterative map model of V^2C control boost converter was established to study the dynamical behaviors of the converter. By using parameter space map and bifurcation diagram, the effects of circuit parameters...A discrete iterative map model of V^2C control boost converter was established to study the dynamical behaviors of the converter. By using parameter space map and bifurcation diagram, the effects of circuit parameters on the bifurcation behaviors of V^2C control and current-mode control boost converters were analyzed. The phase portraits and time-domain waveforms of the V^2C control boost converter were obtained by Runge-Kutta algorithm through piecewise smooth switching model. The research results indicate that V^2C control boost converters can evolve into periodic and chaotic behaviors, and show weaker nonlinear behaviors than current-mode control boost converters.展开更多
A method of controlling chaos in the voltage-mode buck converter is presented by using an improved notch filter feedback control in this paper. The proposed control part comprises a notch filter and a low-pass filter....A method of controlling chaos in the voltage-mode buck converter is presented by using an improved notch filter feedback control in this paper. The proposed control part comprises a notch filter and a low-pass filter. The discrepancy between the outputs of the two filters is introduced into the control prototype of the power converter. In this way, the system period-1 solution is kept unchanged. The harmonic balance method is applied to analysing the variation law of the system bifurcation point, and then the stable range of the feedback gain is ascertained. The results of simulation and experiment are also given finally.展开更多
A novel electron beam welder （ EBW） power supply was developed. Compared with the traditional 3-phase contrail 12-pulse rectifying supplies, it requires a much lower step-up ratio transformer, but a much less output...A novel electron beam welder （ EBW） power supply was developed. Compared with the traditional 3-phase contrail 12-pulse rectifying supplies, it requires a much lower step-up ratio transformer, but a much less output ripple voltage can be obtained. The design of the main circuit of this new power supply is based on PWM buck-boost converter topology. In developing the system a fuzzy PID control method is adopted because of the strong non-linearity and big signal working conditions of the circuit system. The SABER-MATLAB models and fuzzy algorithm were used in developing the fuzzy PID controller. The co-simulation and experimental results displayed that the unit introduced herein has the characteristics of high control precision and antinterference capability.展开更多
A comprehensive predictive strategy was proposed for the neutral-point balancing control of back-to-back three-level converters. The phase currents at both sides and the DC-link capacitor voltages were measured for th...A comprehensive predictive strategy was proposed for the neutral-point balancing control of back-to-back three-level converters. The phase currents at both sides and the DC-link capacitor voltages were measured for the prediction of the neutral-point current. A quality function was found to balance the neutral-point, and a metabolic on-times distribution factor was used as a predicator to minimize the quality function at each switching state. Simulation results show that the proposed method produces smaller ripples in tested signals compared with the established one, namely, 9.15% less in a total harmonic distortion(THD) of line-to-line voltage, 1.08% less in the THD of phase current, and 0.9 V less in the ripple of the neutral-point voltage. The obtained experimental results show that the main harmonics of the line-to-line voltage and the phase current in the proposed method are improved by 10 d B and 6 d B, respectively, and the ripple of neutral-point voltage is halved compared to the established one.展开更多
Solar photovoltaic (PV) generation is one of the most important renewable energy resources, which is a green energy too. The operation and control of the solar PV generation system are important for its application. T...Solar photovoltaic (PV) generation is one of the most important renewable energy resources, which is a green energy too. The operation and control of the solar PV generation system are important for its application. This paper studies the control strategy of the converter used in solar energy photovoltaic (PV) power generation, which can connect with the power grid. The simulation model of the PV generation system is set up to verify the feasibility of the control strategy. And some experiments have been done in the renewable experiment kit of TI Company.展开更多
Sequential control applied to the International Thermonuclear Experimental Re- actor （ITER） poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to th...Sequential control applied to the International Thermonuclear Experimental Re- actor （ITER） poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbax is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.展开更多
The purpose of this paper is to present a new adaptive control method used to adjust the output voltage and current of DC-DC (DC: Direct Current) power converter under different sudden changes in load. The controller ...The purpose of this paper is to present a new adaptive control method used to adjust the output voltage and current of DC-DC (DC: Direct Current) power converter under different sudden changes in load. The controller is a PID controller (Proportional, Integrator, and Differentiator). The gains of the PID controller (KP, KI and KD) tuned using Simulated Annealing (SA) algorithm which is part of Generic Probabilistic Metaheuristic family. The new control system is expected to have a fast transient response feature, with less undershoot of the output voltage and less overshoot of the reactor current. Pulse Width Modulation (PWM) will be utilized to switch the power electronic devices.展开更多
Renewable energy sources require switching regulators as an interface to a load with high efficiency, small size, proper output regulation, and fast transient response. Moreover, due to the nonlinear behavior and swit...Renewable energy sources require switching regulators as an interface to a load with high efficiency, small size, proper output regulation, and fast transient response. Moreover, due to the nonlinear behavior and switching nature of DC-DC power electronic converters, there is a need for high-performance control strategies. This work summarized the dynamic behavior for the three basic switch-mode DC-DC power converters operating in continuous conduction mode, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> buck, boost, and buck-boost. A controller was designed using loop-shaping based on current-mode control that consists of two feedback loops. A high-gain compensator with wide bandwidth was used in the inner current loop for fast transient response. A proportional-integral controller was used in the outer voltage loop for regulation purposes. A proce</span><span style="font-family:Verdana;">dure was proposed for the parameters of the controller that ensures closed-loop</span><span style="font-family:Verdana;"> stability and output voltage regulation. The design-oriented analysis was applied to the three basic switch-mode DC-DC power converters. Experimental results were obtained for a switching regulator with a boost converter of 150 W, which exhibits non-minimum phase behavior. The performance of the controller was tested for voltage regulation by applying large load changes.展开更多
An overview of recent advances in digital control of low-to medium-power DC/DC switching converters is presented.Traditionally,analog electronics methods have dominated in controlling such DC/DC converters.However,wit...An overview of recent advances in digital control of low-to medium-power DC/DC switching converters is presented.Traditionally,analog electronics methods have dominated in controlling such DC/DC converters.However,with the steadily decreasing cost of ICs,the feasibility of digitally controlled DC/DC switching converters has increased sig-nificantly.This paper outlines a sample of digital solutions for DC/DC switching converters to enhance the performance of DC/DC switching converters.Furthermore,latest research activities pertaining to applications for steady-state and dy-namic performance improvement,such as efficiency optimization,controller auto tuning,and capacitor charge balance control,is discussed.These applications demonstrate the significant advantages and potentials of digital control.展开更多
The stop control strategy of modular multilevel converter based HVDC transmission system is proposed. This stop process is divided into stages of energy feedback and energy consumption. The DC voltage controller is co...The stop control strategy of modular multilevel converter based HVDC transmission system is proposed. This stop process is divided into stages of energy feedback and energy consumption. The DC voltage controller is coordinated to the used modules per phase when active power is transmitted prior to reactive power, so that the energy is fed back to the AC power grid connected to the converter station which uses the fixed dc voltage controller. In addition, in view of the different forms connected to the grid, specifically when the converter station supplies power for passive network, the passive converter station can take a certain auxiliary trigger strategy to make its maximum energy feedback to the grid. Finally, a simulation system of the MMC-HVDC system is constructed in Matlab/Simulink environment, and simulation results show that the proposed stop strategies are effective.展开更多
This paper proposes the new cascaded series parallel design for improved dynamic performance of DC-DC buck boost converters by a new Sliding Mode Control (SMC) method. The converter is controlled using Sliding Mode Co...This paper proposes the new cascaded series parallel design for improved dynamic performance of DC-DC buck boost converters by a new Sliding Mode Control (SMC) method. The converter is controlled using Sliding Mode Control method that utilizes the converter’s duty ratio to determine the skidding surface. System modeling and simulation results are presented. The results also showed an improved overall performance over typical PID controller, and there was no overshoot or settling time, tracking the desired output nicely. Improved converter performance and robustness were expected.展开更多
文摘In this paper, we proposed an output voltage stabilization of a DC-DC Zeta converter using hybrid control. We modeled the Zeta converter under continuous conduction mode operation. We derived a switching control law that brings the output voltage to the desired level. Due to infinite switching occurring at the desired level, we enhanced the switching control law by allowing a sizeable output voltage ripple. We derived mathematical models that allow one to choose the desired switching frequency. In practice, the existence of the non-ideal properties of the Zeta converter results in steady-state output voltage error. By analyzing the power loss in the zeta converter, we proposed an improved switching control law that eliminates the steady-state output voltage error. The effectiveness of the proposed method is illustrated with simulation results.
基金supported by Science and Technology Project of the headquarters of the State Grid Corporation of China(No.5500-202324492A-3-2-ZN).
文摘To enhance power flow regulation in scenarios involving large-scale renewable energy transmission via high-voltage direct current(HVDC)links and multi-infeed DC systems in load-center regions,this paper proposes a hybrid modular multilevel converter–capacitor-commutated line-commutated converter(MMC-CLCC)HVDC transmission system and its corresponding control strategy.First,the system topology is constructed,and a submodule configuration method for the MMC—combining full-bridge submodules(FBSMs)and half-bridge submodules(HBSMs)—is proposed to enable direct power flow reversal.Second,a hierarchical control strategy is introduced,includingMMCvoltage control,CLCC current control,and a coordinationmechanism,along with the derivation of the hybrid system’s power flow reversal characteristics.Third,leveraging the CLCC’s fast current regulation and theMMC’s negative voltage control capability,a coordinated power flow reversal control strategy is developed.Finally,an 800 kV MMC-CLCC hybrid HVDC system is modeled in PSCAD/EMTDC to validate the power flow reversal performance under a high proportion of full-bridge submodule configuration.Results demonstrate that the proposed control strategy enables rapid(1-s transition)and smooth switching of bidirectional power flow without modifying the structure of primary equipment:the transient fluctuation ofDC voltage from the rated value(UdcN)to themaximumreverse voltage(-kUdcN)is less than 5%;the DC current strictly follows the preset characteristic curve with a deviation of≤3%;the active power reverses continuously,and the system maintains stable operation throughout the reversal process.
文摘This paper presents an advanced control strategy for DC-DC buck converters utilizing Non-Minimal State Space (NMSS) representation combined with Proportional-Integral-Plus (PIP) control, optimized through Linear Quadratic Regulator (LQR) design. The proposed approach leverages NMSS to eliminate the need for state observers, enhancing robustness against model mismatch and improving overall system performance. The PIP controller extends traditional PI control by incorporating additional dynamic feedback. Experimental results demonstrate that the NMSS-PIP-LQR controlled buck converter achieves excellent dynamic performance. The design procedure is fully documented, and microcontroller implementation issues are discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61371033 and 51407054)the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201442)the Fundamental Research Funds for the Central Universities of China(Grant No.2682016CX035)
文摘By analyzing the output voltage ripple of a buck-boost converter with large equivalent series resistance（ESR） of output capacitor, one valley voltage-mode controller for buck-boost converter is proposed. Considering the fact that the increasing and decreasing slopes of the inductor current are assumed to be constant during each switching cycle, an especial sampleddata model of valley voltage-mode controlled buck-boost converter is established. Based on this model, the dynamical effect of an output-capacitor time-constant on the valley voltage-mode controlled buck-boost converter is revealed and analyzed via the bifurcation diagrams, the movements of eigenvalues, the Lyapunov exponent spectra, the boundary equations,and the operating-state regions. It is found that with gradual reduction of output-capacitor time-constant, the buck-boost converter in continuous conduction mode（CCM） shows the evolutive dynamic behavior from period-1 to period-2, period-4, period-8, chaos, and invalid state. The stability boundary and the invalidated boundary are derived theoretically by stability analysis, where the stable state of valley voltage-mode controlled buck-boost converter can enter into an unstable state, and the converter can shift from the operation region to a forbidden region. These results verified by time-domain waveforms and phase portraits of both simulation and experiment indicate that the sampled-data model is correct and the time constant of the output capacitor is a critical factor for valley voltage-mode controlled buck-boost converter, which has a significant effect on the dynamics as well as control stability.
基金supported by the National Natural Science Foundation of China(No.61121003)
文摘Reaction flywheel is a significant actuator for satellites＇ attitude control. To improve output torque and rotational speed accuracy for reaction flywheel, this paper reviews the modeling and control approaches of DC-DC converters and presents an application of the variable structure system theory with associated sliding regimes. Firstly, the topology of reaction flywheel is constructed. The small signal linearization process for a buck converter is illustrated. Then, based on the state averaging models and reaching qualification expressed by the Lee derivative, the general results of the sliding mode control （SMC） are analyzed. The analytical equivalent control laws for reaction flywheel are deduced detailedly by selecting various sliding surfaces at electromotion, energy consumption braking, reverse connection braking stages. Finally, numerical and experimental examples are presented for illustrative purposes. The results demonstrate that favorable agreement is established between the simulations and experiments. The proposed control strategy achieves preferable rotational speed regulation, strong rejection of modest disturbances, and high-precision output torque and rotational speed tracking abilities.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10247005 and 70571017）, the Guangxi New Century Foundation for Ten, Hundred and Thousand Talents （Grant No 2002226）.
文摘Based on the mechanism for the generation of chaos in a buck converter, a pole placement method is proposed and applied to controlling the chaos in a circuit. The control circuit is designed and tested. Numerical calculation and circuit implementation demonstrate the validity of this chaos control method.
文摘In this paper, a robust sliding mode controller for the control of dc-dc buck converter is designed and analyzed. Dynamic equations describing the buck converter are derived and sliding mode controller is designed. A two-loop control is employed for a buck converter. The robustness of the sliding mode controlled buck converter system is tested for step load changes and input voltage variations. The theoretical predictions are validated by means of simulations. Matlab/Simulink is used for the simulations. The simulation results are presented. The buck converter is tested with operating point changes and parameter uncertainties. Fast dynamic response of the output voltage and robustness to load and input voltage variations are obtained.
文摘This article studies a design and implementation of state-feedback control problem for dc-dc Positive Output Super Lift Luo (POSLL) converter by considering the line and load disturbances for needing desired power source for various portable electronic equipments like battery charger, hard disk drives, medical device, LED TV etc. The POSLL’s dynamic performance becomes non-linear in nature;the designed controller able to get superior dynamic performance given by load estimation is done by using an observer and by combining the state-feedback control with the load estimator, a controller which is explicitly developed with strong robustness using separation principle. An effectual stability analysis is exemplified to prove that by carefully selecting the state feedback control and observer gain matrix, the output voltage of the dc-dc POSLL converter tracks the desired value irrespective of the uncertainties. Extensive simulation is carried out using MATLAB/Simulink model. The result based on time domain analysis is done by using the controllers for various disturbances given to the converter.
文摘This paper considers controlling and maximizing the absorbed power of wave energy converters for irregular waves. With respect to physical constraints of the system, a model predictive control is applied. Irregular waves’ behavior is predicted by Kalman filter method. Owing to the great influence of controller parameters on the absorbed power, these parameters are optimized by imperialist competitive algorithm. The results illustrate the method’s efficiency in maximizing the extracted power in the presence of unknown excitation force which should be predicted by Kalman filter.
基金The National Natural Science Foundation of China (No.50677056)the Natural Science Foundations of Jiangsu Province (No.BK2009105)
文摘A discrete iterative map model of V^2C control boost converter was established to study the dynamical behaviors of the converter. By using parameter space map and bifurcation diagram, the effects of circuit parameters on the bifurcation behaviors of V^2C control and current-mode control boost converters were analyzed. The phase portraits and time-domain waveforms of the V^2C control boost converter were obtained by Runge-Kutta algorithm through piecewise smooth switching model. The research results indicate that V^2C control boost converters can evolve into periodic and chaotic behaviors, and show weaker nonlinear behaviors than current-mode control boost converters.
基金Project supported by the National Natural Science Foundation of China （Grant No 50677071）.
文摘A method of controlling chaos in the voltage-mode buck converter is presented by using an improved notch filter feedback control in this paper. The proposed control part comprises a notch filter and a low-pass filter. The discrepancy between the outputs of the two filters is introduced into the control prototype of the power converter. In this way, the system period-1 solution is kept unchanged. The harmonic balance method is applied to analysing the variation law of the system bifurcation point, and then the stable range of the feedback gain is ascertained. The results of simulation and experiment are also given finally.
文摘A novel electron beam welder （ EBW） power supply was developed. Compared with the traditional 3-phase contrail 12-pulse rectifying supplies, it requires a much lower step-up ratio transformer, but a much less output ripple voltage can be obtained. The design of the main circuit of this new power supply is based on PWM buck-boost converter topology. In developing the system a fuzzy PID control method is adopted because of the strong non-linearity and big signal working conditions of the circuit system. The SABER-MATLAB models and fuzzy algorithm were used in developing the fuzzy PID controller. The co-simulation and experimental results displayed that the unit introduced herein has the characteristics of high control precision and antinterference capability.
基金Project(61074018)supported by the National Natural Science Foundation of ChinaProject(2012kfjj06)supported by Hunan Province Key Laboratory of Smart Grids Operation and Control(Changsha University of Science and Technology),China
文摘A comprehensive predictive strategy was proposed for the neutral-point balancing control of back-to-back three-level converters. The phase currents at both sides and the DC-link capacitor voltages were measured for the prediction of the neutral-point current. A quality function was found to balance the neutral-point, and a metabolic on-times distribution factor was used as a predicator to minimize the quality function at each switching state. Simulation results show that the proposed method produces smaller ripples in tested signals compared with the established one, namely, 9.15% less in a total harmonic distortion(THD) of line-to-line voltage, 1.08% less in the THD of phase current, and 0.9 V less in the ripple of the neutral-point voltage. The obtained experimental results show that the main harmonics of the line-to-line voltage and the phase current in the proposed method are improved by 10 d B and 6 d B, respectively, and the ripple of neutral-point voltage is halved compared to the established one.
文摘Solar photovoltaic (PV) generation is one of the most important renewable energy resources, which is a green energy too. The operation and control of the solar PV generation system are important for its application. This paper studies the control strategy of the converter used in solar energy photovoltaic (PV) power generation, which can connect with the power grid. The simulation model of the PV generation system is set up to verify the feasibility of the control strategy. And some experiments have been done in the renewable experiment kit of TI Company.
基金supported by International Cooperation Project of Ministry of Science and Technology of China(4.1.P2.CN.01/1A)
文摘Sequential control applied to the International Thermonuclear Experimental Re- actor （ITER） poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbax is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.
文摘The purpose of this paper is to present a new adaptive control method used to adjust the output voltage and current of DC-DC (DC: Direct Current) power converter under different sudden changes in load. The controller is a PID controller (Proportional, Integrator, and Differentiator). The gains of the PID controller (KP, KI and KD) tuned using Simulated Annealing (SA) algorithm which is part of Generic Probabilistic Metaheuristic family. The new control system is expected to have a fast transient response feature, with less undershoot of the output voltage and less overshoot of the reactor current. Pulse Width Modulation (PWM) will be utilized to switch the power electronic devices.
文摘Renewable energy sources require switching regulators as an interface to a load with high efficiency, small size, proper output regulation, and fast transient response. Moreover, due to the nonlinear behavior and switching nature of DC-DC power electronic converters, there is a need for high-performance control strategies. This work summarized the dynamic behavior for the three basic switch-mode DC-DC power converters operating in continuous conduction mode, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> buck, boost, and buck-boost. A controller was designed using loop-shaping based on current-mode control that consists of two feedback loops. A high-gain compensator with wide bandwidth was used in the inner current loop for fast transient response. A proportional-integral controller was used in the outer voltage loop for regulation purposes. A proce</span><span style="font-family:Verdana;">dure was proposed for the parameters of the controller that ensures closed-loop</span><span style="font-family:Verdana;"> stability and output voltage regulation. The design-oriented analysis was applied to the three basic switch-mode DC-DC power converters. Experimental results were obtained for a switching regulator with a boost converter of 150 W, which exhibits non-minimum phase behavior. The performance of the controller was tested for voltage regulation by applying large load changes.
文摘An overview of recent advances in digital control of low-to medium-power DC/DC switching converters is presented.Traditionally,analog electronics methods have dominated in controlling such DC/DC converters.However,with the steadily decreasing cost of ICs,the feasibility of digitally controlled DC/DC switching converters has increased sig-nificantly.This paper outlines a sample of digital solutions for DC/DC switching converters to enhance the performance of DC/DC switching converters.Furthermore,latest research activities pertaining to applications for steady-state and dy-namic performance improvement,such as efficiency optimization,controller auto tuning,and capacitor charge balance control,is discussed.These applications demonstrate the significant advantages and potentials of digital control.
文摘The stop control strategy of modular multilevel converter based HVDC transmission system is proposed. This stop process is divided into stages of energy feedback and energy consumption. The DC voltage controller is coordinated to the used modules per phase when active power is transmitted prior to reactive power, so that the energy is fed back to the AC power grid connected to the converter station which uses the fixed dc voltage controller. In addition, in view of the different forms connected to the grid, specifically when the converter station supplies power for passive network, the passive converter station can take a certain auxiliary trigger strategy to make its maximum energy feedback to the grid. Finally, a simulation system of the MMC-HVDC system is constructed in Matlab/Simulink environment, and simulation results show that the proposed stop strategies are effective.
文摘This paper proposes the new cascaded series parallel design for improved dynamic performance of DC-DC buck boost converters by a new Sliding Mode Control (SMC) method. The converter is controlled using Sliding Mode Control method that utilizes the converter’s duty ratio to determine the skidding surface. System modeling and simulation results are presented. The results also showed an improved overall performance over typical PID controller, and there was no overshoot or settling time, tracking the desired output nicely. Improved converter performance and robustness were expected.
