Regenerative Active Front End based motor-drive systems for servo press applications

Regenerative Active Front End "AFE" based motor-drive systems represent a very important segment in the industry. The main advantages of these drives are they do not require a braking resistor, provide an input current with significantly reduced Total Harmonic Distortion " THD", and regenerate / draw power from the supply at a unity power factor, enhanced resiliency during grid abnormal conditions and voltage sags. Moreover, AFE based motor-drive systems can inject reactive power to the line if needed thus providing power factor correction within the limits of the thermal capacity of the drive. Due to their significant advantages, these systems are penetrating several markets. One of these critical markets is the servo press applications where high pressures must be provided almost instantaneously for metal forming applications. This paper is centered on introducing innovative adaptive DC bus control algorithms to optimize energy consumption and system design in such applications.