摘要：
独立运行的单相全桥逆变器通常工作于电压源模式,将直流源侧能量传送至交流负载侧.由于负载的多样性,系统具有复杂的动态特性.阻感性负载(如电机、空调等)连接至逆变器交流输出时,系统出现振荡失稳现象.首先,建立单相逆变器系统数学模型,并结合比例-谐振(PR)控制器特征对模型进行线性化处理,得出了单相逆变器系统的输出阻抗表达.其次,采用阻抗比判据方法,绘制阻抗比的奈奎斯特曲线,确定了系统不稳定运行的拒绝域,从而解析性地得到了感性负载、控制系数、滤波电容等对拒绝域的影响.结果表明,在实际运行参数范围内,随逆变器的比例系数、滤波电感的减小,或者滤波电容、滤波电感串联电阻的增大,阻感性负载下的单相逆变器趋于稳定,可得到稳定的输出电压波形.%The standalone single-phase H-bridge inverter usually works in voltage-mode control,converting DC power to AC local loads.Due to the diversity of loads,the inverter may have rich dynamic behaviors.Oscillation instability occurs when the inductive loads (e.g.,electric machine and air conditioner) are connected to AC output of the inverter.Firstly,a mathematical model is established for the single-phase inverter system,and the linearization is processed by taking into account the characteristics of proportional-resonant (PR) controller.Then the inverter output impedance can be derived.Secondly,according to the Nyquist criterion,the impedance ratio curves are plotted to determine the forbidden region of operation.The forbidden region is studied in an analytical way by varying the inductive load,control factor and filter capacitor.The results show that single-phase inverters with inductive loads can achieve stability by the reduction of proportional coefficient and filter inductance,or increase of filter capacitance and series resistor filter inductance in practical parameter ranges.
