| The shipbuilding industry in China is at a historical stage of transitioning from traditional fossil fuels to clean new energy.Promoting marine hybrid systems is of great significance in addressing energy depletion and air pollution issues.However,the bottleneck of mode switching control technology limits the widespread application of hybrid ships in China.This article focuses on the problem of power system performance degradation when ships switch from PTH mode to main propulsion mode,establishes a high hybrid power system simulation model,and proposes the optimal control scheme for mode switching based on multi-objective optimization algorithm,providing a theoretical basis for the breakthrough of mode switching control technology.This article completes the modeling of key equipment modules based on the power architecture and equipment parameters of a typical inland gas electric hybrid ship.The test data validation results show that the maximum deviation of the exhaust temperature in the simulation results can reach 7.91% at low speed,and the maximum deviation of other steady-state and dynamic parameters is only 1.08% and 4.18%,respectively.Since the exhaust temperature is not the key parameter for mode switching research,it can have a high tolerance.In general,the simulation error of the simulation model under both steady-state and dynamic conditions is less than 5%,meeting the demand for mode switching optimization research.This article is based on simulation models and traditional mode switching control strategies,selecting the connection speed,connection time,and compensation torque as key parameters that affect the mode switching performance,and completing the analysis of the impact of a single variable on the system mode switching performance.The simulation results show that the mode switching performance is better when the connection speed,connection time,and compensation torque are 700r/min,10 s,and200Nm,respectively.The torque compensation strategy can reduce the gas engine speed overshoot rate and NOX emission rate from 12.66% and 16.26g/k Wh under the traditional mode switching strategy to 9.17% and 2.09g/k Wh,respectively.This article selects three intelligent optimization algorithms,namely simulated annealing algorithm,particle swarm optimization algorithm,and non dominated sorting genetic algorithm,to solve the multi-objective optimization problem of mode switching.For high hybrid power systems,the optimal mode switching control parameter configuration scheme is studied.The research results indicate that the large torque compensation and fast exit strategy developed based on non dominated sorting genetic algorithm has the best control effect,which can further reduce the speed overshoot rate and NOX emission rate of the gas engine to 5.89% and 0.56g/k Wh,achieving fast and stable connection.This article is based on the inspection mode switching optimization strategy of the gas-electric hybrid power test bench,and has successively completed performance verification tests for the optimization strategy of connection speed,compensation torque,and the optimization strategy of "connection speed+compensation torque".The results show that the single variable optimization strategy with connection speed of 700r/min and compensation torque of 200 Nm,as well as the multi-objective optimization strategy with connection speed of 750r/min and compensation torque of 300 Nm,have good mode switching performance.Among them,the "connection speed+compensation torque" control strategy can reduce the overshoot rate and switching time of the gas engine speed from 12.547% and 11.733 seconds under the traditional mode switching strategy to6.395% and 7.267 seconds,respectively.Finally,this article proposes a mode switching optimization strategy of "connection speed+compensation torque" to improve the mode switching power,economy,emissions,and speed of high hybrid power ships.For the target ship,the optimal connection speed and compensation torque are 750r/min and 300 Nm,respectively;For other ships of the same type,this can be used as a reference to design a suitable mode switching optimization scheme for oneself. |
