Minimisation of reactive component values in back-to-back converters

The back-to-back AC-AC power converter, consisting of two PWM inverter bridges with a common DC link, is considered as a future replacement for the conventional inverter drive. The topology offers the advantages of high power factor and regenerative capability. The factors determining the size of the reactive components are discussed. Guidelines for selecting components are derived from consideration of the required DC link voltage, the input current quality, the stability of the DC link voltage control loop, and the transient response of the system. Simulation shows the feasibility of implementing a 7.5 kW converter with a DC link capacitance of 50 mu F. This result suggests that it may be possible to use nonelectrolytic capacitors in the DC link.<>