摘要
针对并网系统谐波预测问题,提出引入逆变器实际输出谐波电流建立谐波阻抗模型的方案。首先分析并网系统谐波谐振原理,对单相LCL型并网逆变器进行阻抗建模。为提高阻抗模型准确性,在分析逆变器低频特性的基础上,将单个逆变器并网谐波电流考虑到阻抗模型中,建立谐波阻抗模型,与电路模型仿真对比结果验证了模型的有效性。利用提出的谐波阻抗模型,对多逆变器并网系统进行谐波交互分析及谐波预测建模,以8个并网逆变器为例,分析谐振对并网谐波电流和公共接入点(PCC)处谐波电压的影响,谐波预测模型和电路模型对比仿真结果验证了该多逆变器谐波预测模型的有效性和准确性。
Aimed at harmonic prediction of grid-connected systems,a harmonic impedance modeling scheme is proposed based on output harmonic current of inverter. The grid-connected system harmonic resonance theory was analyzed for impedance modeling of single-phase LCL grid-connected inverter. The low frequency characteristic of inverter was analyzed. Further,the harmonic current of single LCL gridconnected inverter was considered to obtain the harmonic impedance model,which is in good agreement with the simulation results of circuit model. The harmonic impedance model was used for harmonic interaction analysis and harmonic prediction modeling of multi-inverter grid-connected systems. An example of eight grid-connected inverters was proposed,and the resonance effect was analyzed for harmonic current and harmonic voltage over point of common coupling( PCC). This harmonic prediction model was compared with circuit model to prove its effectiveness and accuracy.
引文
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