A novel repetitive control strategy for the output waveform of single-phase CVCF inverters is presented. In this scheme, the inverse transfer function of inverter is used as a compensator to obtain stable and satisfy harmonic rejection. Besides, PD controller is adopted to improve transient performance. Simulation and experimental results, which are gotten from a DSP-based 400Hz, 5.5KW inverter, indicate that the proposed control scheme can achieve not only low THD during steady-state operation but also fast transient response during load step change.
当采用小波分解方法对低压配电系统短路故障进行早期检测时,门限值的合理设置对故障检测的可靠性及灵敏度是至关重要的。本文通过对低压配电系统电动机的起动、过载及线路短路的暂态过程进行深入研究,得到了基于三次 B 样条小波变换的短路故障早期检测门限值的设置方法。该方法与全波傅里叶模值检测方法相比,不仅可将短路故障与电动机起动、过载正确区分开,而且还可超高速地检测出短路故障。仿真结果证实了该方法的正确性及有效性。
