Fault tolerant digital control of 2 MVA parallelable frequency converters for harbor applications

This paper deals with the design of a fault tolerant digital control of high power, parallelable frequency converters for harbor application. With the aim to yield a high degree of system availability the control algorithm must be able to automatically switch from parallel to single mode operation in case of fault. Scalability is a further key feature of the proposed control strategy: in order to increase the output power rating, the control strategy can parallel more than two converters increasing, in turn, the availability of the whole system as well. An inclusive set of MATLAB simulations shows that the proposed control algorithm makes the whole power system complying with the specifications in terms of THD, power efficiency and dynamic response. A full set of measurements, performed on a scaled converter prototype, confirmed the simulation results.