Optimization of the DC ripple energy compensating circuit on a single-phase voltage source PWM rectifier

This paper presents parameter optimization of the compensating circuit for the reduction of the DC ripple energy on a single-phase voltage source PWM rectifier. In the single-phase PWM rectifier, it is well known that a power pulsation with twice the utility frequency is contained in the output power. In a conventional PWM rectifier, electrolytic capacitors with large capacitance have been used in order to smooth the DC voltage. However, lifetime of those capacitors is shortened by the power pulsation with twice utility frequency. The authors have been studied two kinds of DC ripple compensation circuits, such the authors call an inductive storage method and a capacitive storage method, those enable to transfer the ripple energy appeared on the output DC capacitors into the energy in an additional inductor and additional small capacitors. Hence, extension of the lifetime of the converter can be expected because the small film capacitor substitutes for the large electrolytic capacitors. Moreover, the inductance and capacitance region in which the DC ripple energy can be compensated completely and the overall dimensions of the energy storage devices are shown. Finally, experimental results of compensation characteristics on both the steady state and transient state are discussed.