具有良好负载适应性的软开关电流混合控制单相逆变器

Soft-Switch Current Hybrid Controlled Single-Phase Inverter with Good Load Adaptability

负载适应性是衡量逆变器性能的重要参数。滞环电流控制的开关频率不固定,导致滤波器难以设计且输出电流频谱较分散。采用单极性BCM调制模式控制的逆变器有低损耗、高功率密度的特性,但单极性控制的开关频率在负载电压过零点降低到零,BCM调制模式对负载电流敏感,对于容性和感性负载,在负载电流过零点附近有大的频率畸变。由此提出一种单双极性混合BCM调制模式来消除开关频率的过零和高频畸变,同时保持了单极性BCM模式的效率优势。最后搭建试验平台进行验证,试验结果表明提出的单双极性混合BCM控制对频率有很好的负载适应性。

Load adaptability is an important parameter to measure the performance of an inverter.The switching frequency of hysteresis current control is not fixed,which makes it difficult to design the filter and the output current spectrum is scattered.The inverter controlled byunipolar Boundary Current Mode(BCM)modulation has the characteristics of low cost and high power density,but the switching frequency controlled by unipolar control will reduce to zero when the load voltage passes zero.The BCM modulation is sensitive to the load current,and there is a large frequency distortion near the load current crossing zero for capacitive and inductive load.A unipolar-bipolar hybrid BCM modulation was proposed to eliminate the zero-crossing and high-frequency distortion of switching frequencies while maintaining the efficiency advantage of the unipolar BCM modulation.Finally,an experimental platform was set up for verification.The experimental results showed that the proposed unipolar-bipolar hybrid BCM modulation had good load adaptability to frequency.