In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)i...In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.展开更多
Flexible traction substations (FTSSs) integrating power converters, solar photovoltaics (PVs), and energy storage systems (ESSs) are beneficial for electric railways (ERs) evolving toward a sustainable and efficient s...Flexible traction substations (FTSSs) integrating power converters, solar photovoltaics (PVs), and energy storage systems (ESSs) are beneficial for electric railways (ERs) evolving toward a sustainable and efficient system. However, traction load and PV generation are uncertain and fluctuating, unfavorable to efficient PV energy consumption in ERs. Thus, this paper proposes a power flow control strategy for FTSSs. First, a real-time power flow optimization method is proposed to calculate the output power references of the back-to-back converter (BTBC) and ESS. It aims for efficient regenerative braking energy and PV energy utilization and negative sequence current suppression. Then, a model predictive power control (MPPC) scheme is designed for BTBC to track output power and DC-bus voltage references quickly and accurately. It includes a revised dynamic reference generation method and a model-based double-line frequency ripple (DLFR) filter. Meanwhile, an MPPC scheme for a bidirectional DC-DC converter is designed to regulate output power of ESS, which realizes accurate power reference tracking and smooth operational mode transition. Finally, the validity of the proposed strategy is confirmed through simulations and experiments.展开更多
First, a three-tier coordinated scheduling system consisting of a distribution network dispatch layer, a microgrid centralized control layer, and local control layer in the energy internet is proposed. The multi-time ...First, a three-tier coordinated scheduling system consisting of a distribution network dispatch layer, a microgrid centralized control layer, and local control layer in the energy internet is proposed. The multi-time scale optimal scheduling of the microgrid based on Model Predictive Control（MPC） is then studied, and the optimized genetic algorithm and the microgrid multi-time rolling optimization strategy are used to optimize the datahead scheduling phase and the intra-day optimization phase. Next, based on the three-tier coordinated scheduling architecture, the operation loss model of the distribution network is solved using the improved branch current forward-generation method and the genetic algorithm. The optimal scheduling of the distribution network layer is then completed. Finally, the simulation examples are used to compare and verify the validity of the method.展开更多
Wind power plants(WPPs)are increasingly mandated to provide temporary frequency support to power systems during contingencies involving significant power shortages.However,the frequency support capabilities of WPPs un...Wind power plants(WPPs)are increasingly mandated to provide temporary frequency support to power systems during contingencies involving significant power shortages.However,the frequency support capabilities of WPPs under derated operations remain insufficiently investigated,highlighting the potential for further improvement of the frequency nadir.This paper proposes a bi-level optimized temporary frequency support(OTFS)strategy for a WPP.The implementation of the OTFS strategy is collaboratively accomplished by individual wind turbine(WT)controllers and the central WPP controller.First,to exploit the frequency support capability of WTs,the stable operational region of WTs is expanded by developing a novel dynamic power control approach in WT controllers.This approach synergizes the WTs'temporary frequency support with the secondary frequency control of synchronous generators,enabling WTs to release more kinetic energy without causing a secondary frequency drop.Second,a model predictive control strategy is developed for the WPP controller.This strategy ensures that multiple WTs operating within the expanded stable region are coordinated to minimize the magnitude of the frequency drop through efficient kinetic energy utilization.Finally,comprehensive case studies are conducted on a real-time simulation platform to validate the effectiveness of the proposed strategy.展开更多
基金National Natural Science Foundation of China(Nos.51767013,52067013)。
文摘In predictive direct power control(PDPC)system of three-phase pulse width modulation(PWM)rectifier,grid voltage sensor makes the whole system more complex and costly.Therefore,third-order generalized integrator(TOGI)is used to generate orthogonal signals with the same frequency to estimate the grid voltage.In addition,in view of the deviation between actual and reference power in the three-phase PWM rectifier traditional PDPC strategy,a power correction link is designed to correct the power reference value.The grid voltage sensor free algorithm based on TOGI and the corrected PDPC strategy are applied to three-phase PWM rectifier and simulated on the simulation platform.Simulation results show that the proposed method can effectively eliminate the power tracking deviation and the grid voltage.The effectiveness of the proposed method is verified by comparing the simulation results.
基金supported in part by the National Science Fund for Excellent Young Scholars of China 52122707in part by the National Key R&D Program of China 2021YFB2601500in part by the Sichuan Science and Technology Program 2022NSFSC1896.
文摘Flexible traction substations (FTSSs) integrating power converters, solar photovoltaics (PVs), and energy storage systems (ESSs) are beneficial for electric railways (ERs) evolving toward a sustainable and efficient system. However, traction load and PV generation are uncertain and fluctuating, unfavorable to efficient PV energy consumption in ERs. Thus, this paper proposes a power flow control strategy for FTSSs. First, a real-time power flow optimization method is proposed to calculate the output power references of the back-to-back converter (BTBC) and ESS. It aims for efficient regenerative braking energy and PV energy utilization and negative sequence current suppression. Then, a model predictive power control (MPPC) scheme is designed for BTBC to track output power and DC-bus voltage references quickly and accurately. It includes a revised dynamic reference generation method and a model-based double-line frequency ripple (DLFR) filter. Meanwhile, an MPPC scheme for a bidirectional DC-DC converter is designed to regulate output power of ESS, which realizes accurate power reference tracking and smooth operational mode transition. Finally, the validity of the proposed strategy is confirmed through simulations and experiments.
基金supported by Beijing Municipal Science Technology commission research(No.Z171100000317003)
文摘First, a three-tier coordinated scheduling system consisting of a distribution network dispatch layer, a microgrid centralized control layer, and local control layer in the energy internet is proposed. The multi-time scale optimal scheduling of the microgrid based on Model Predictive Control（MPC） is then studied, and the optimized genetic algorithm and the microgrid multi-time rolling optimization strategy are used to optimize the datahead scheduling phase and the intra-day optimization phase. Next, based on the three-tier coordinated scheduling architecture, the operation loss model of the distribution network is solved using the improved branch current forward-generation method and the genetic algorithm. The optimal scheduling of the distribution network layer is then completed. Finally, the simulation examples are used to compare and verify the validity of the method.
基金supported by the National Key R&D Program of China under Grant 2021YFB2400500。
文摘Wind power plants(WPPs)are increasingly mandated to provide temporary frequency support to power systems during contingencies involving significant power shortages.However,the frequency support capabilities of WPPs under derated operations remain insufficiently investigated,highlighting the potential for further improvement of the frequency nadir.This paper proposes a bi-level optimized temporary frequency support(OTFS)strategy for a WPP.The implementation of the OTFS strategy is collaboratively accomplished by individual wind turbine(WT)controllers and the central WPP controller.First,to exploit the frequency support capability of WTs,the stable operational region of WTs is expanded by developing a novel dynamic power control approach in WT controllers.This approach synergizes the WTs'temporary frequency support with the secondary frequency control of synchronous generators,enabling WTs to release more kinetic energy without causing a secondary frequency drop.Second,a model predictive control strategy is developed for the WPP controller.This strategy ensures that multiple WTs operating within the expanded stable region are coordinated to minimize the magnitude of the frequency drop through efficient kinetic energy utilization.Finally,comprehensive case studies are conducted on a real-time simulation platform to validate the effectiveness of the proposed strategy.
