Flux estimation based dc bus voltage control in marine dc power system

DC power systems are increasingly being considered for marine applications as they provide certain advantages. Proper modeling and control approach of the system components with suitable dc bus voltage control and power sharing among the generators are important aspects for smooth functioning of the marine dc power system. Conventional bus voltage control in ac systems is usually achieved by using automatic voltage regulator (AVR), which requires the measurement of the generator terminal voltage. Since generators interfaced with the voltage source converter (VSC) system are envisaged in the marine dc power system, determination of generator terminal voltage for voltage control becomes difficult as the measurement is comprised primarily of PWM waveforms. This paper implements the closed loop flux estimation of brushless synchronous generator (BLSG) for dc bus voltage control. This paper also covers the droop control for power sharing among the generators. The proposed method is implemented in Opal-RT which is a real-time simulation platform and the results are discussed in the paper. Apart from the results, the limitations of the closed loop flux control are also highlighted in the paper.