Internal Voltage Phase-Amplitude Dynamic Analysis With Interface Friendly Back-To-Back Power Converter Average Model for Less Power Electronics-Based More-Electric Ship

Kai Ni,Rui Liang,Mohammed Alkahtani,Huiqing Wen,Yihua Hu

doi:10.1109/access.2019.2927617

Abstract

The advancement in power electronics techniques provides a strong impetus for the adoption of medium-voltage direct current (MVDC) shipboard power system (SPS). However, high fault protection difficulty and cost are the major challenges. In this paper, a partially power decoupled SPS based on the doubly fed induction machine (DFIM) propulsion load is presented to increase the system safety level by using less power electronics. Different from a grid-connected DFIM-based system, the on-board power of the proposed DFIM-SPS is supplied from standalone synchronous generators, and its system dynamics need to be further investigated. An interface friendly average model for the back-to-back power converter (BTBPC) in DFIM-SPS is proposed for system-level dynamic study, which reduces the simulation time and is easy for physical understanding. The stator and BTBPC of DFIM are regarded as separate voltage vectors in the system, and small-signal modeling is carried out in the electromechanical control timescale to analyze the internal voltage phase-amplitude dynamics. The control effects of rotor speed control (RSC), reactive power control (RPC), and phase-locked loop (PLL) are considered in the modeling process. The simulations are performed to study the control effects on DFIM-SPS in MATLAB/Simulink, with the effectiveness of the proposed BTBPC average model validated.

Highlights

The latest more-electric ships (MESs) tend to adopt DC power distribution architectures [1]–[3] due to the benefits of no power factor issue, no skin effect, and easy integration of energy storage systems
As this paper focuses on the system dynamics of doubly fed induction machine (DFIM)-shipboard power system (SPS) in electromechanical control timescale, the DC-bus voltage Vdc is assumed to be stable, only the control of load-side converter (LSC) is considered
SIMULATION RESULTS AND DISCUSSION The simulation studies are carried out in Matlab/Simulink to verify the operation of a DFIM-SPS by applying the proposed interface friendly back-to-back power converter (BTBPC) average model, and the control effects of phase-locked loop (PLL), rotor speed control (RSC) and reactive power control (RPC) on DFIM stator phaseamplitude dynamics are investigated

Summary

INTRODUCTION

The latest more-electric ships (MESs) tend to adopt DC power distribution architectures [1]–[3] due to the benefits of no power factor issue, no skin effect, and easy integration of energy storage systems. For the sake of carrying out system-level studies, average-value modeling (AVM) methods for power converters were presented for MVDC-SPS [9]–[11] to release the computational burden and reduce the simulation time. A large number of researchers focused on improving the system safety level by proposing different control strategies for fully rated motor drive systems to improve the stability and reliability of MVDC-SPS [24]–[31] These methods are applicable for certain cases, they do not deal with the intrinsic safety issues caused by applying DC power distribution and extensive use of power electronics. The RSC and RPC that are in the electromechanical control timescale are the main focus, and they play the most important role in assessing the system dynamics of DFIM-SPS with respect to the source-load interactions. The variables of SG are with the subscript ‘‘SG’’, while no additional subscript is added for the variables of DFIM

SG AND EXS

LINEARIZATION OF INTERNAL VOLTAGE VECTOR

LINEARIZATION OF RSC AND RPC

SIMULATION RESULTS AND DISCUSSION

CONCLUSION

DFIM PARAMETERS USED IN SIMULATION