The VBC has the functions to control the circulating current and capacitor voltage, to protect converter valves and to monitor converter valves. The valve control receives commands and signals from the pole (converter) control to control/monitors the conduction of power electronic devices within the valves. The key function is Interfacing the converter control system to many (hundreds or more) of the individual power electronics modules within the HVDC power converter. The Valve Base Electronics (VBE) communicates with a large number of power electronics modules using an industry standard passive optical communication technology that allows each module to be controlled and monitored in a tightly-synchronized, time-critical and reliable manner while minimizing the number of fibers needed without compromising redundancy. Some of the functions handled by VBC includes modulating reference voltage of bridge arm based on command received from converter control, Current balance control including the circulating current between upper and lower bridge arms and between different phases, Voltage balance control by calculating the right number of working submodules (SMs) ensuring the capacitors’ voltages within a reasonable range, Valve and bridge arm protection and monitoring.