Double-Sided Control of DC-link Voltage in Back-to-Back Converters

This paper proposes a simple and effective dc-link voltage control method for power electronics converters sharing the same dc-link capacitor. The method basically incorporates both of the converters that are connected to the same dc-link capacitor in the voltage control process via two topological modifications on the conventional dc-link voltage control method. As a result, the effective dc-link voltage control bandwidth can be increased, which was usually confined in conventional single-sided control by the current control bandwidth of the converter that is responsible for the dc-link voltage control. The primary advantage of such a bandwidth increase is improved disturbance rejection characteristics so that the dc-link voltage regulation becomes more resistant to the dynamic changes of system variables. Furthermore, such incorporation can yield continued dc-link voltage regulation under a fault condition in one of the converters so that the remaining converter can still continue some services such as reactive current provision. The viability of the proposed control method is demonstrated via simulations.