Feedback Energy Efficiency Optimization Of Propeller Propulsion Load Simulation

With the development of ship propulsion technology,it has been widely used that power propulsion system as a power system to simulate the running state of the propeller.The propeller is an important part of the power propulsion system,for its load characteristics affect the performance of the ship power propulsion system.The brushless DC motor replaces mechanical commutation with electronic commutation,this paper will use it as load motor to study the propeller load simulation control strategy.Firstly,based on the basic principle of the propeller load simulation,the load characteristics of the propeller are studied,and the torque characteristic curves under different working conditions are analyzed,and the corresponding coefficients are improved.Then,according to the relationship between the propeller and the ship,the mathematical model is established,and the propeller simulation model is built.The main regenerative braking state control strategy of brushless DC motor is analyzed.Aiming at the disadvantages of diode freewheeling in unipolar PWM modulation and larger switching loss in bipolar PWM modulation,a novel regenerative braking PWM modulation mode: PWM_OFF_PWM is proposed.Based on the proposed PWM modulation method,the influences on diode freewheeling and commutation torque ripple are studied,and the expression of DC bus feedback current about the speed and duty cycle are analyzed,and conclusion can be drawn that the duty ration can be adjusted to control feedback current and feedback efficiency.The correctness and effectiveness of theoretical analysis are verified in MATLAB simulation model.The propeller load simulation system is built,where,the output load torque of propeller is used as the given torque of the load motor,and the electromagnetic torque of the load motor can be consistent with the propeller load torque by controlling the load motor.The simulation results show that the load simulation system can operate normally under different conditions of ship.Based on the design of the brushless DC motor control system,build the hardware experimental platform for debugging,the experimental results verify the correctness and feasibility of the control system and control method.