This paper presents a grid connected photovoltaic system (PV) with a proposed high voltage conversion ratio DC-DC converter which steps up the variable low input voltages of photovoltaic module to the required DC link...This paper presents a grid connected photovoltaic system (PV) with a proposed high voltage conversion ratio DC-DC converter which steps up the variable low input voltages of photovoltaic module to the required DC link voltage. This voltage is applied to an H-bridge inverter which converts DC voltage into AC voltage and a low pass filter is used to filter the output. By adjusting the duty ratio of switches in DC-DC converter, the magnitude of inverter’s output voltage is controlled. The frequency and phase synchronization are ensured by a feedback signal taken from the grid. In this way, inverter is synchronized and connected with the grid to meet the energy demand. The PV system has been designed and simulated.展开更多
提出一种考虑分布式光伏无功和储能有功参与的配电网电压分层控制方法。首先,分析了由分布式光伏与负荷时空不匹配引起的高/低电压问题,依据配电网拓扑以及线路参数计算得到配电网节点电压与注入功率的无功-电压、有功-电压近似灵敏度...提出一种考虑分布式光伏无功和储能有功参与的配电网电压分层控制方法。首先,分析了由分布式光伏与负荷时空不匹配引起的高/低电压问题,依据配电网拓扑以及线路参数计算得到配电网节点电压与注入功率的无功-电压、有功-电压近似灵敏度矩阵。其次,在第一层控制中,提出了分布式光伏参与配电网调压的无功-电压下垂系数优化控制方法,通过求解电压优化模型得到分布式光伏逆变器的最优下垂系数,从而计算出其无功输出。当光伏逆变器的无功容量不足时,提出了第二层控制,即储能参与调压的有功-电压自适应下垂控制策略,储能逆变器的下垂控制系数根据储能荷电状态(state of charge,SOC)与所在节点电压自适应调整,既考虑了储能的容量,又实现了储能功率和SOC的相对均衡控制。最后,以一实际10节点配电网系统作为算例验证了所提方法的有效性。展开更多
In this paper, a perturb and observe(P&O) based voltage regulator(POVR) and a capacitor compensator(CC)circuit are proposed for the implementation on 31-level asymmetrical switch-diode based multi-level DC-link(ML...In this paper, a perturb and observe(P&O) based voltage regulator(POVR) and a capacitor compensator(CC)circuit are proposed for the implementation on 31-level asymmetrical switch-diode based multi-level DC-link(MLDCL) inverter. Since the application of MLDCL in a standalone photovoltaic(PV) system requires constant DC voltages from PV panels, the POVR strategy is deployed to regulate the voltage along with the capability to deliver the maximum power at full load.Boost DC-DC converters are used as the interface between the panels and the inverter for the POVR operation. The results show that POVR is capable of achieving the desired fixed DC voltages even under varying environmental and load conditions,with a steady 230 V at the output. At full load, the standalone system successfully delivers 97.21% of the theoretical maximum power. Additionally, CC is incorporated to mitigate voltage spikes at the output when supplying power to inductive loads.It successfully eliminates the spikes and also reduces the total harmonic distortion(THD) of output current and voltage from more than 10% to less than 5%, as recommended in IEEE 519 standard.展开更多
The generation of electricity based on renewable energy sources,parti-cularly Photovoltaic(PV)system has been greatly increased and it is simply insti-gated for both domestic and commercial uses.The power generated fr...The generation of electricity based on renewable energy sources,parti-cularly Photovoltaic(PV)system has been greatly increased and it is simply insti-gated for both domestic and commercial uses.The power generated from the PV system is erratic and hence there is a need for an efficient converter to perform the extraction of maximum power.An improved interleaved Single-ended Primary Inductor-Converter(SEPIC)converter is employed in proposed work to extricate most of power from renewable source.This proposed converter minimizes ripples,reduces electromagnetic interference due tofilter elements and the contin-uous input current improves the power output of PV panel.A Crow Search Algo-rithm(CSA)based Proportional Integral(PI)controller is utilized for controlling the converter switches effectively by optimizing the parameters of PI controller.The optimized PI controller reduces ripples present in Direct Current(DC)vol-tage,maintains constant voltage at proposed converter output and reduces over-shoots with minimum settling and rise time.This voltage is given to single phase grid via 1�Voltage Source Inverter(VSI).The command pulses of 1�VSI are produced by simple PI controller.The response of the proposed converter is thus improved with less input current.After implementing CSA based PI the efficiency of proposed converter obtained is 96%and the Total Harmonic Distor-tion(THD)is found to be 2:4%.The dynamics and closed loop operation is designed and modeled using MATLAB Simulink tool and its behavior is performed.展开更多
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
文摘This paper presents a grid connected photovoltaic system (PV) with a proposed high voltage conversion ratio DC-DC converter which steps up the variable low input voltages of photovoltaic module to the required DC link voltage. This voltage is applied to an H-bridge inverter which converts DC voltage into AC voltage and a low pass filter is used to filter the output. By adjusting the duty ratio of switches in DC-DC converter, the magnitude of inverter’s output voltage is controlled. The frequency and phase synchronization are ensured by a feedback signal taken from the grid. In this way, inverter is synchronized and connected with the grid to meet the energy demand. The PV system has been designed and simulated.
文摘提出一种考虑分布式光伏无功和储能有功参与的配电网电压分层控制方法。首先,分析了由分布式光伏与负荷时空不匹配引起的高/低电压问题,依据配电网拓扑以及线路参数计算得到配电网节点电压与注入功率的无功-电压、有功-电压近似灵敏度矩阵。其次,在第一层控制中,提出了分布式光伏参与配电网调压的无功-电压下垂系数优化控制方法,通过求解电压优化模型得到分布式光伏逆变器的最优下垂系数,从而计算出其无功输出。当光伏逆变器的无功容量不足时,提出了第二层控制,即储能参与调压的有功-电压自适应下垂控制策略,储能逆变器的下垂控制系数根据储能荷电状态(state of charge,SOC)与所在节点电压自适应调整,既考虑了储能的容量,又实现了储能功率和SOC的相对均衡控制。最后,以一实际10节点配电网系统作为算例验证了所提方法的有效性。
基金supported in part by the Postgraduate Fellowship from Universiti Sains Malaysia and in part by University Sains Malaysia (No. RUI1001/PELECT/8014027)。
文摘In this paper, a perturb and observe(P&O) based voltage regulator(POVR) and a capacitor compensator(CC)circuit are proposed for the implementation on 31-level asymmetrical switch-diode based multi-level DC-link(MLDCL) inverter. Since the application of MLDCL in a standalone photovoltaic(PV) system requires constant DC voltages from PV panels, the POVR strategy is deployed to regulate the voltage along with the capability to deliver the maximum power at full load.Boost DC-DC converters are used as the interface between the panels and the inverter for the POVR operation. The results show that POVR is capable of achieving the desired fixed DC voltages even under varying environmental and load conditions,with a steady 230 V at the output. At full load, the standalone system successfully delivers 97.21% of the theoretical maximum power. Additionally, CC is incorporated to mitigate voltage spikes at the output when supplying power to inductive loads.It successfully eliminates the spikes and also reduces the total harmonic distortion(THD) of output current and voltage from more than 10% to less than 5%, as recommended in IEEE 519 standard.
文摘The generation of electricity based on renewable energy sources,parti-cularly Photovoltaic(PV)system has been greatly increased and it is simply insti-gated for both domestic and commercial uses.The power generated from the PV system is erratic and hence there is a need for an efficient converter to perform the extraction of maximum power.An improved interleaved Single-ended Primary Inductor-Converter(SEPIC)converter is employed in proposed work to extricate most of power from renewable source.This proposed converter minimizes ripples,reduces electromagnetic interference due tofilter elements and the contin-uous input current improves the power output of PV panel.A Crow Search Algo-rithm(CSA)based Proportional Integral(PI)controller is utilized for controlling the converter switches effectively by optimizing the parameters of PI controller.The optimized PI controller reduces ripples present in Direct Current(DC)vol-tage,maintains constant voltage at proposed converter output and reduces over-shoots with minimum settling and rise time.This voltage is given to single phase grid via 1�Voltage Source Inverter(VSI).The command pulses of 1�VSI are produced by simple PI controller.The response of the proposed converter is thus improved with less input current.After implementing CSA based PI the efficiency of proposed converter obtained is 96%and the Total Harmonic Distor-tion(THD)is found to be 2:4%.The dynamics and closed loop operation is designed and modeled using MATLAB Simulink tool and its behavior is performed.
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。
