Performance analysis, filter component sizing, and controller structure selection of small capacitor diode rectifier front end inverter drives

In this study, the input filter design and dc-bus voltage control of ac motor drives utilizing low capacitance film capacitor are investigated. The dc-bus voltage instability problem arising due to the resonance between the dc-bus capacitor and circuit inductances is explained. A dimensioning algorithm of dc-bus filter components for stable operation is given. The simulation results of the low capacitance motor drives with and without dc-link inductor are provided to observe the stability of the dc-bus at different resonant frequencies. Voltage and current mode active stabilization methods found in literature aiming to actively damp the resonances in the dc-bus are analyzed and evaluated in the simulations for 2.2 kW and 37 kW rated induction motors driving constant torque load (CTL) and variable torque loads (VTL). Results are analyzed both in terms of input (line current) power quality and output (motor motion) quality.