The rapid development of new energy power generation technology and the transformation of power electronics in the core equipment of source-grid-load drives the power system towards the“double-high”development patte...The rapid development of new energy power generation technology and the transformation of power electronics in the core equipment of source-grid-load drives the power system towards the“double-high”development pattern of“high proportion of renewable energy”and“high proportion of power electronic equipment”.To enhance the transient performance of AC/DC hybrid microgrid(HMG)in the context of“double-high,”aπtype virtual synchronous generator(π-VSG)control strategy is applied to bidirectional interface converter(BIC)to address the issues of lacking inertia and poor disturbance immunity caused by the high penetration rate of power electronic equipment and new energy.Firstly,the virtual synchronous generator mechanical motion equations and virtual capacitance equations are used to introduce the virtual inertia control equations that consider the transient performance of HMG;based on the equations,theπ-type equivalent control model of the BIC is established.Next,the inertia power is actively transferred through the BIC according to the load fluctuation to compensate for the system’s inertia deficit.Secondly,theπ-VSG control utilizes small-signal analysis to investigate howthe fundamental parameters affect the overall stability of the HMG and incorporates power step response curves to reveal the relationship between the control’s virtual parameters and transient performance.Finally,the PSCAD/EMTDC simulation results show that theπ-VSG control effectively improves the immunity of AC frequency and DC voltage in the HMG system under the load fluctuation condition,increases the stability of the HMG system and satisfies the power-sharing control objective between the AC and DC subgrids.展开更多
Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefor...Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefore,in future“double high”power systems,research on the control technology of GFM converters will become an urgent demand.In this paper,we first introduce the basic principle of GFM control and then present five currently used control strategies for GFM converters:droop control,power synchronization control(PSC),virtual synchronous machine control(VSM),direct power control(DPC),and virtual oscillator control(VOC).These five strategies can independently establish voltage phasors to provide inertia to the system.Among these,droop control is the most widely used strategy.PSC and VSM are strategies that simulate the mechanical characteristics of synchronous generators;thus,they are more accurate than droop control.DPC regulates the active power and reactive power directly,with no inner current controller,and VOC is a novel method under study using an oscillator circuit to realize synchronization.Finally,we highlight key technologies and research directions to be addressed in the future.展开更多
The increasing adoption of grid-forming converters(GFMCs)stems from their capacity to furnish voltage and frequency support for power grids.Nevertheless,GFMCs employing the current reference saturation limiting method...The increasing adoption of grid-forming converters(GFMCs)stems from their capacity to furnish voltage and frequency support for power grids.Nevertheless,GFMCs employing the current reference saturation limiting method often exhibit instability during various transient disturbances including grid voltage sags,frequency variations,and phase jumps.To address this problem,this paper proposes a virtual power angle synchronous(δv-SYN)control method.The fundamental of this method is to achieve synchronization with the grid using the virtual power angleδv instead of the active power.The transient stability characteristics of the proposed method are theoretically elucidated using a novel virtual power angle-power angle(δv-δ)model.The key benefit of the proposed method is its robustness to various grid strengths and diverse forms of transient disturbances,eliminating the requirement for fault identification or control switching.Moreover,it can offer grid-forming support to the grid during grid faults.Hardware-in-the-loop experimental results validate the theoretical analysis and the performance of the proposed method.展开更多
The brushless doubly-fed induction generator(BDFIG)presents significant potential for application in wind power systems,primarily due to the elimination of slip rings and brushes.The application of virtual synchronous...The brushless doubly-fed induction generator(BDFIG)presents significant potential for application in wind power systems,primarily due to the elimination of slip rings and brushes.The application of virtual synchronous control(VSynC)has been demonstrated to effectively augment the inertia of BDFIG systems.However,the dynamic characteristics and stability of BDFIG under weak grid conditions remain largely unexplored.The critical stabilizing factors for BDFIG-based wind turbines(WTs)are methodically investigated,and an enhanced VSynC method based on linear active disturbance rejection control(LADRC)is proposed.The stability analysis reveals that the proposed method can virtually enhance the stability of the grid-connected system under weak grid conditions.The accuracy of the theoretical analysis and the effectiveness of the proposed method are affirmed through extensive simulations and detailed experiments.展开更多
基金funded by“The Fourth Phase of 2022 Advantage Discipline Engineering-Control Science and Engineering”,grant number 4013000063.
文摘The rapid development of new energy power generation technology and the transformation of power electronics in the core equipment of source-grid-load drives the power system towards the“double-high”development pattern of“high proportion of renewable energy”and“high proportion of power electronic equipment”.To enhance the transient performance of AC/DC hybrid microgrid(HMG)in the context of“double-high,”aπtype virtual synchronous generator(π-VSG)control strategy is applied to bidirectional interface converter(BIC)to address the issues of lacking inertia and poor disturbance immunity caused by the high penetration rate of power electronic equipment and new energy.Firstly,the virtual synchronous generator mechanical motion equations and virtual capacitance equations are used to introduce the virtual inertia control equations that consider the transient performance of HMG;based on the equations,theπ-type equivalent control model of the BIC is established.Next,the inertia power is actively transferred through the BIC according to the load fluctuation to compensate for the system’s inertia deficit.Secondly,theπ-VSG control utilizes small-signal analysis to investigate howthe fundamental parameters affect the overall stability of the HMG and incorporates power step response curves to reveal the relationship between the control’s virtual parameters and transient performance.Finally,the PSCAD/EMTDC simulation results show that theπ-VSG control effectively improves the immunity of AC frequency and DC voltage in the HMG system under the load fluctuation condition,increases the stability of the HMG system and satisfies the power-sharing control objective between the AC and DC subgrids.
基金supported by the National Natural Science Foundation of China(No.52177122)the“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 21050100)the Youth Innovation Promotion Association CAS(No.2018170)。
文摘Grid-forming(GFM)converters can provide inertia support for power grids through control technology,stabilize voltage and frequency,and improve system stability,unlike traditional grid-following(GFL)converters.Therefore,in future“double high”power systems,research on the control technology of GFM converters will become an urgent demand.In this paper,we first introduce the basic principle of GFM control and then present five currently used control strategies for GFM converters:droop control,power synchronization control(PSC),virtual synchronous machine control(VSM),direct power control(DPC),and virtual oscillator control(VOC).These five strategies can independently establish voltage phasors to provide inertia to the system.Among these,droop control is the most widely used strategy.PSC and VSM are strategies that simulate the mechanical characteristics of synchronous generators;thus,they are more accurate than droop control.DPC regulates the active power and reactive power directly,with no inner current controller,and VOC is a novel method under study using an oscillator circuit to realize synchronization.Finally,we highlight key technologies and research directions to be addressed in the future.
基金supported in part by the National Natural Science Foundation of China(No.52377186)the Natural Science Foundation of Guangdong Province(No.2024A1515012428)+1 种基金the Science and Technology Planning Project of Guangdong Province,China(No.2023A1111120023)the Basic and Applied Basic Research Foundation of Guangdong Province(No.2022A1515240026)。
文摘The increasing adoption of grid-forming converters(GFMCs)stems from their capacity to furnish voltage and frequency support for power grids.Nevertheless,GFMCs employing the current reference saturation limiting method often exhibit instability during various transient disturbances including grid voltage sags,frequency variations,and phase jumps.To address this problem,this paper proposes a virtual power angle synchronous(δv-SYN)control method.The fundamental of this method is to achieve synchronization with the grid using the virtual power angleδv instead of the active power.The transient stability characteristics of the proposed method are theoretically elucidated using a novel virtual power angle-power angle(δv-δ)model.The key benefit of the proposed method is its robustness to various grid strengths and diverse forms of transient disturbances,eliminating the requirement for fault identification or control switching.Moreover,it can offer grid-forming support to the grid during grid faults.Hardware-in-the-loop experimental results validate the theoretical analysis and the performance of the proposed method.
基金supported by the National Natural Science Foundation of China(No.52077222)the Shandong Provincial Natural Science Foundation(No.ZR2023QE156)。
文摘The brushless doubly-fed induction generator(BDFIG)presents significant potential for application in wind power systems,primarily due to the elimination of slip rings and brushes.The application of virtual synchronous control(VSynC)has been demonstrated to effectively augment the inertia of BDFIG systems.However,the dynamic characteristics and stability of BDFIG under weak grid conditions remain largely unexplored.The critical stabilizing factors for BDFIG-based wind turbines(WTs)are methodically investigated,and an enhanced VSynC method based on linear active disturbance rejection control(LADRC)is proposed.The stability analysis reveals that the proposed method can virtually enhance the stability of the grid-connected system under weak grid conditions.The accuracy of the theoretical analysis and the effectiveness of the proposed method are affirmed through extensive simulations and detailed experiments.
