Perfect wave oscillation suppression with reflection coefficients adaptation in PWM motor drives with long feeding cables

A perfect wave oscillation cancellation scheme is a proposed method for suppressing overvoltage in adjustable speed PWM motor drives through long feeding cables. It is a new solution to the overvoltage problem, which cascades the proposed filter with the transmission line achieving a pure delay transfer between inverter and motor, completely removing the pulse reflection that causes the overvoltage problem. Simple voltage transfer function with time delay is derived under a distortionless transmission assumption, which is valid in practice. The proposed PWM input voltage form is calculated by inverting the voltage transfer function. Also, the unknown reflection coefficients are identified through a simple adaptive algorithm. The simulation results verify the performance of the proposed method, which is compared with a previous method.