Modeling and Simulation of Electric Thermal Coupling Model for Ship Electric Propulsion Equipment

The ship electric propulsion system is a complex large-scale system that includes multiple disciplines such as electrical, mechanical, thermal, control, and electromagnetic. The traditional single-domain system simulation method is difficult to fully describe its system status and performance. This paper takes the propulsion device part of the ship electric propulsion system as the research object, establishes various equipment components and system models based on Modelica, and conducts simulation and experimental verification. Based on the basic modeling ideas of modularization and multi-domain unification of Modelica language, the application scenarios of IGBT models at different time scales are analyzed, the influence of IGBT junction temperature on its electrical characteristics is considered, an IGBT electrothermal coupling model suitable for system-level simulation is established, and the thermal path method is used to realize the simulation calculation of IGBT junction temperature. The mathematical model of the six-phase permanent magnet synchronous motor is established, the motor loss is analyzed, and the motor mathematical model is improved on the basis of considering loss and thermal coupling. Based on the idea of modular modeling, the six-phase permanent magnet synchronous motor is decomposed into multiple sub-modules such as electrical system module, electromechanical conversion module, electromagnetic module, mechanical module, loss module, and heat transfer network module. A six phase permanent magnet synchronous motor model based on Modelica language was established, and the connector mechanism is used to realize the multi-domain unification of the motor model. The vector control module is added to jointly simulate the inverter model and the motor model, and experiments are carried out on the permanent magnet synchronous motor towing test platform to verify the correctness of the established model. The results show that the model is relatively accurate and has certain design verification value for actual engineering.