Research On Current Sensor Error Correction Of Ship Permanent Magnet Synchronous Propulsion Motor

In recent decades,electric propulsion ship has been widely used.As an important part of electric propulsion system,the high-performance control strategy of permanent magnet synchronous motor has become a research hotspot.However,in the vector control system of permanent magnet synchronous motor,the current measurement error introduced by the relevant circuit in the current sampling link will cause the motor speed ripple and deterioration of phase current,which will reduce the control performance and efficiency of the system,and the safety and reliability of equipment.To solve these problems,the current measurement error compensation strategies for ship permanent magnet synchronous propulsion motor were studied in this thesis.First,the mathematical model of permanent magnet synchronous motor and the vector control system are established,and a simulation model is set up for validation.The influence on speed by q-axis current measurement errors is analysis in detail and the quantitative relationship between them was deduced.Second,to eliminate the influence of current measurement offset error on the system,compensation strategy is designed to estimate and compensate the offset error by using the feature that the 1st-order speed ripple amplitude contains the information about the offset error.Series second order generalized integrator is designed to extract accurate 1st-order speed ripple quadrature component and calculate the amplitude.Particle swarm optimization is used to adjust the PI controller parameters in the strategy to overcome the difficulty of parameter adjusting and achieve the best compensation.Third,in order to further improve the accuracy of compensation and realize the real-time self-adaptation of parameters,the current harmonic compensation strategy is designed.Cascade decoupled second-order generalized integrator with higher extraction accuracy is designed to extract the1st-and 2nd-harmonics of d-q axis current.An adaptive linear neural network compensator is designed to output the d-q axes compensating current to eliminate 1st-and2nd-harmonics of the d-q axes current and speed,and improve the phase current state.In addition,an improved harmonic current compensation strategy is designed for the condition with 1st-and 2nd-ripple in load torque.d-q axes current can be compensated by adjusting only one group of weights.Finally,the experiment is carried out on a permanent magnet synchronous motor experimental platform to verify the validity and feasibility of the two compensation strategies proposed above.Simulink results and experimental results show that the proposed compensation strategies can effectively eliminate the speed ripple and deterioration of phase current caused by current measurement error.Comparing with the existing current measurement error compensation strategy,it has the advantages of simple structure,wide application range and independent of motor parameters.