Plug-and-play realization of the virtual infinite capacitors

摘要

Apparatus (22, 90) for controlling DC voltage on a bus (26) includes a switched power converter (32), including a pair of terminals (31) for connection between the bus and a ground (28), a buffering capacitor (48), and switching circuitry (36) configured to control a voltage between the terminals while a charge on the buffering capacitor varies over a predefined range in response to a current flowing through the terminals. A control circuit (50, 98) is coupled to monitor the voltage between the terminals, the current, and a voltage on the buffering capacitor, and is configured to adjust the voltage between the terminals by controlling the switching circuitry in response to changes in the monitored voltages and current so that the terminal voltage is maintained at a reference voltage value, which can be adjusted adaptively so as to converge to the equilibrium voltage of the DC bus. Consequently, the apparatus need have only two terminals, and hence is easy to install.