Voltage dip immunity of PWM drives with ride-through capabilities

Variable frequency PWM drives (VFD) are part of many industrial processes today. Back a few years ago, VFD susceptibility of voltage dips was a main concern for end users. Over the years, manufacturers improved their design in power loss ride-through by utilizing new mitigation techniques including controlling the undervoltage of the intermediate DC link with the use of load regeneration. Thought the techniques worked in many applications, questions arise to how much these VFD new capabilities are effective to withstand voltages dips in specific applications and how VFD models from different manufacturers can be compared with each other. This paper is aimed to evaluate and compare the immunity of five (5) industrial 100 hp PWM VFD from five (5) different manufacturers under a series of voltage dips of different magnitudes and durations.