级联型高压变频器过流保护的缺陷分析及改进措施

Analysis on defects of over-current protection of cascade high-voltage frequency converter and improvement measures

分析了目前级联型高压变频器过流保护回路存在的问题及过流保护误动的原因,论述了现有保护方案对变频器正常运行造成的损害。提出了将硬件保护改为软、硬件互为备用的新方案及改进型的全波傅里叶算法。工程实践表明,新过流保护可提高级联型高压变频器运行的可靠性。

The problems existing in the over-current protection circuit of current cascade high-voltage frequency converters and the reasons causing incorrect tripping of the over-current protection were analyzed.The hazard of the existing over-current protection for normal operation of the converter was expounded.The hardware protection was transformed into a new protection scheme,in which the hardware protection and software protection are used as standby for each other,and an improved full wave Fourier algorithm was put forward.The engineering practice shows that the new over-current protection scheme can improve the operation reliability of the cascade high-voltage frequency converter.