| High-efficiency PMSM drive systems are frequently employed in a variety of ship equipment because of the ongoing advancements in distribution and drive technology.The large-capacity electrolytic capacitors in conventional power drive equipment inverters are gradually being replaced by low-capacity film capacitors in order to increase the dependability of ship power drive equipment and decrease the failure rate of drive equipment.In addition,because ship motor drive systems have a cascaded control structure,the motor drive control system may have poor damping control characteristics,which can cause oscillations in the inverter’s DC-link voltage.Therefore,this thesis takes the lacking-damping PMSM drive system as the research object,and proposes corresponding DC-link voltage stabilization control methods for different control methods’ system impedance characteristics to ensure the reliability of ship drive equipment operation.The oscillation mechanism of the DC-link voltage in the ship lacking-damping drive control system is extensively discussed in the study.The generally employed topological structure of the ship PMSM drive system is subjected to equivalent analysis,and the impedance properties of the lacking-damping PMSM drive system under field oriented control and finite constraint set model predictive control are determined.The theoretical underpinnings for the stable control method of the DC-link voltage are provided by a comparison of the control features and computational complexity of the two methods.A hardware experimental platform for the lacking-damping drive control system is also built,providing experimental support for the stable control approach.An active impedance compensation method based on field oriented control is proposed to address the issue of system instability caused by negative impedance in lacking-damping drive control systems.The impedance signal is compensated in the pulse width modulation strategy to reconstruct the reference voltage of the DC-link,and the inductive component of the motor is used to absorb the oscillation energy of the system,thereby achieving the suppression of DClink voltage oscillation.Small signal analysis is used to determine the input and output impedances of the drive system after impedance compensation,and Middlebrook’s stability criterion is used to demonstrate the stability of the active impedance compensation approach.The suggested technique was tested using an experimental platform for the lacking-damping drive control system.The findings demonstrate that the method has a straightforward structure,precise impedance compensation,and may lessen the negative effects of the compensation loop on the motor system.The method has significant advantages in suppressing DC-link voltage disturbance.A voltage predictive control method based on finite constraint set model predictive control is proposed to solve the problem of DC-link voltage oscillation in lacking-damping drive control systems.By analyzing the mathematical model of the inverter input filter,the predictive equation of the direct voltage is derived and established,and the constraint of the direct voltage is designed to achieve synchronous control of the direct voltage and motor current.The weight coefficients of the cost function are determined by the oscillation amplitude of the DC-link voltage,which accelerates the convergence speed of the direct voltage when the oscillation amplitude is relatively large.The full-order state observer is used to obtain the filter inductor current,which simplifies the design of the hardware measurement circuit and saves hardware costs.The system characteristic equation under voltage predictive control is derived,and the stability of the system with voltage constraint is proven by using the Routh-Hurwitz criterion.Experimental validation was performed on the built hardware experimental platform,and the results showed that,compared with the active impedance compensation method,the proposed method has a stronger ability to suppress voltage oscillation and lower motor quadrature axis current ripple.A nonlinear extended state observer-based amplitude control set model predictive control method is proposed to address the problem of poor steady-state performance in DC-link voltage control.An amplitude control set is constructed in the rotating coordinate system,avoiding coordinate transformation operations for vector resolution.The design range of the control set is reduced by utilizing the motor voltage equation,improving the operational efficiency of the method.The disturbance current of the predictive model is actively observed and compensated using the nonlinear extended-state observer,which reduces the impact of parameter changes on the predictive voltage and current.The frequency domain analysis method is used to configure the parameters of the nonlinear extended state observer,and the stability of the system is demonstrated using the root locus method,improving the feasibility of engineering applications.Experimental verification is conducted on a hardware experimental platform of the control system,and the experimental results show that the proposed method effectively suppresses the predictive error with parameter variation and reduces the harmonic content of the DC-link voltage and motor phase current.In summary,this thesis investigates the issue of DC-link voltage oscillations in a lackingdamping PMSM drive control system under different control scenarios.A DC-link reference voltage active impedance compensation method is proposed under field oriented control,simplifying the impedance compensation structure and parameter configuration process while reducing its adverse effects on the motor system.Furthermore,a DC-link voltage predictive control and optimization method is proposed under finite constraint set model predictive control,which accelerates the convergence speed of DC-link voltage oscillations,reduces the impact of time-varying disturbances on the prediction model,and enhances the overall control performance of the drive system.Finally,experimental verification is conducted to validate the effectiveness of the above control methods. |
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