为解决光伏接入电网引起的并网点电压越限问题,增大光伏在电网中的渗透率,可充分利用并网光伏逆变器的无功调压能力向电网提供无功支撑。为此,从电网电压降落角度研究光伏发电接入电网前后并网点电压的变化,并深入分析了德国电气工程师...为解决光伏接入电网引起的并网点电压越限问题,增大光伏在电网中的渗透率,可充分利用并网光伏逆变器的无功调压能力向电网提供无功支撑。为此,从电网电压降落角度研究光伏发电接入电网前后并网点电压的变化,并深入分析了德国电气工程师协会(Verband Deutscher Elektrotechniker)提出的无功功率控制策略,在此基础上,提出一种基于并网点电压幅值与光伏有功出力的Q(U,P)无功功率控制策略。该控制策略继承了德国电气工程师协会提出的策略的优点,在此控制策略下,光伏系统所有逆变器参与电网电压调节,在维持电网电压在要求范围的前提下,无功吸收总量最低,电网有功、无功损耗最小。算例结果验证了该策略的有效性。展开更多
Renewable generation interfaced through gridforming converters are proposed as a replacement for synchronous generators in power systems.However,compared to the synchronous generator,the power electronics converter ha...Renewable generation interfaced through gridforming converters are proposed as a replacement for synchronous generators in power systems.However,compared to the synchronous generator,the power electronics converter has a strict limit on the current to avoid overcurrent damage.The gridforming converter acts like a voltage source,directily controlling the voltage.This conflicts with the operation of the conventional current limit control,which is applied to a current source.The switch between the voltage control and current control aimed to impose the current limit leads to synchronization instability.This paper proposes a novel control scheme which can be applied to the grid forming voltage control in order to enforce current limits.The proposed method has been verified through simulation and hardware tests in both symmetrical and asymmetrical faults to perform current suppression while maintaining synchronization stability in the voltage control mode.展开更多
The occurrence of power flow reversal and off-limit of the voltage on common bus becomes more frequent because of the increasing penetration of renewable energy sources(RES)in microgrids.To guarantee the safe and stab...The occurrence of power flow reversal and off-limit of the voltage on common bus becomes more frequent because of the increasing penetration of renewable energy sources(RES)in microgrids.To guarantee the safe and stable operation,adjusting the power output of RES-based inverters to avoid the off-limit voltage is necessary.Considering the apparent power characteristics of inverters,as well as the minimum participation of active power,a voltage control strategy based on stage division to be within the voltage limit is investigated in this paper.In the case of unknown demand and distribution of loads,the proposed control strategy is able to make full use of the apparent power to regulate voltage using simple calculations,while the performance in economical operation is satisfactory.Simulation results prove the effectiveness of the proposed method on the common bus off-limit voltage adjustment.展开更多
This paper puts forward a new practical voltage source converter(VSC)based AC-DC converter model suitable for conducting power flow assessment of multi-terminal VSCbased high-voltage direct current(VSC-MTDC)systems.Th...This paper puts forward a new practical voltage source converter(VSC)based AC-DC converter model suitable for conducting power flow assessment of multi-terminal VSCbased high-voltage direct current(VSC-MTDC)systems.The model uses an advanced method to handle the operational limits and control modes of VSCs into the power flow formulation.The new model is incorporated into a unified framework encompassing AC and DC power grids and is solved by using the Newton-Raphson method to enable quadratically convergent iterative solutions.The use of complementarity constraints,together with the Fischer-Burmeister function,is proposed to enable the seamless incorporation of operational control modes of VSC and automatic enforcement of any converter’s operational limits that become violated during the iterative solution process.Thus,a dedicated process for checking limits is no longer required.Furthermore,all existing relationships between the VSC control laws and their operational limits are considered directly during the solution of the power flow problem.The applicability of the new model is demonstrated with numerical examples using various multi-terminal AC-DC transmission networks,one of which is a utility-sized power system.展开更多
本文提出了一种新颖的电压限位电路.该电路该采用电压跟随器FOLLOWER和模拟二选一选择器结构,其中的比较器采用PNP双极型三极管,从而使输出更精确地跟随输入.与传统电压限压电路相比,该电路在设定的电压范围内,输出电压能更好地跟随输...本文提出了一种新颖的电压限位电路.该电路该采用电压跟随器FOLLOWER和模拟二选一选择器结构,其中的比较器采用PNP双极型三极管,从而使输出更精确地跟随输入.与传统电压限压电路相比,该电路在设定的电压范围内,输出电压能更好地跟随输入电压变化,在输出端误差小,设定的电压范围以外,电路输出能固定在某一特定值.本电路基于0.35 um BCD工艺,对所设计电路进行了仿真验证.仿真结果表明,当下限阈值VTH-设定在0.5V,上限阈值VTH＋设定在2V,输入电压VIN输入范围在0～ 3V内时,输出电压精确跟随VIN的变化而变化.展开更多
文摘为解决光伏接入电网引起的并网点电压越限问题,增大光伏在电网中的渗透率,可充分利用并网光伏逆变器的无功调压能力向电网提供无功支撑。为此,从电网电压降落角度研究光伏发电接入电网前后并网点电压的变化,并深入分析了德国电气工程师协会(Verband Deutscher Elektrotechniker)提出的无功功率控制策略,在此基础上,提出一种基于并网点电压幅值与光伏有功出力的Q(U,P)无功功率控制策略。该控制策略继承了德国电气工程师协会提出的策略的优点,在此控制策略下,光伏系统所有逆变器参与电网电压调节,在维持电网电压在要求范围的前提下,无功吸收总量最低,电网有功、无功损耗最小。算例结果验证了该策略的有效性。
基金This work was supported in part by the Science Foundation Ireland(SFI)under Grant SFI/15/SPP/E3125。
文摘Renewable generation interfaced through gridforming converters are proposed as a replacement for synchronous generators in power systems.However,compared to the synchronous generator,the power electronics converter has a strict limit on the current to avoid overcurrent damage.The gridforming converter acts like a voltage source,directily controlling the voltage.This conflicts with the operation of the conventional current limit control,which is applied to a current source.The switch between the voltage control and current control aimed to impose the current limit leads to synchronization instability.This paper proposes a novel control scheme which can be applied to the grid forming voltage control in order to enforce current limits.The proposed method has been verified through simulation and hardware tests in both symmetrical and asymmetrical faults to perform current suppression while maintaining synchronization stability in the voltage control mode.
基金jointly supported by the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110794)the Research and Development Program Project in Key Areas of Guangdong Province(No.2021B0101230001).
文摘The occurrence of power flow reversal and off-limit of the voltage on common bus becomes more frequent because of the increasing penetration of renewable energy sources(RES)in microgrids.To guarantee the safe and stable operation,adjusting the power output of RES-based inverters to avoid the off-limit voltage is necessary.Considering the apparent power characteristics of inverters,as well as the minimum participation of active power,a voltage control strategy based on stage division to be within the voltage limit is investigated in this paper.In the case of unknown demand and distribution of loads,the proposed control strategy is able to make full use of the apparent power to regulate voltage using simple calculations,while the performance in economical operation is satisfactory.Simulation results prove the effectiveness of the proposed method on the common bus off-limit voltage adjustment.
基金supported by Fondo de Sustentabilidad Energética SENERConacyt,México(No.246949 and No.249795)。
文摘This paper puts forward a new practical voltage source converter(VSC)based AC-DC converter model suitable for conducting power flow assessment of multi-terminal VSCbased high-voltage direct current(VSC-MTDC)systems.The model uses an advanced method to handle the operational limits and control modes of VSCs into the power flow formulation.The new model is incorporated into a unified framework encompassing AC and DC power grids and is solved by using the Newton-Raphson method to enable quadratically convergent iterative solutions.The use of complementarity constraints,together with the Fischer-Burmeister function,is proposed to enable the seamless incorporation of operational control modes of VSC and automatic enforcement of any converter’s operational limits that become violated during the iterative solution process.Thus,a dedicated process for checking limits is no longer required.Furthermore,all existing relationships between the VSC control laws and their operational limits are considered directly during the solution of the power flow problem.The applicability of the new model is demonstrated with numerical examples using various multi-terminal AC-DC transmission networks,one of which is a utility-sized power system.
文摘本文提出了一种新颖的电压限位电路.该电路该采用电压跟随器FOLLOWER和模拟二选一选择器结构,其中的比较器采用PNP双极型三极管,从而使输出更精确地跟随输入.与传统电压限压电路相比,该电路在设定的电压范围内,输出电压能更好地跟随输入电压变化,在输出端误差小,设定的电压范围以外,电路输出能固定在某一特定值.本电路基于0.35 um BCD工艺,对所设计电路进行了仿真验证.仿真结果表明,当下限阈值VTH-设定在0.5V,上限阈值VTH＋设定在2V,输入电压VIN输入范围在0～ 3V内时,输出电压精确跟随VIN的变化而变化.
