Research On Performance Optimization Of IPT System For Modern Tram

As an important part of the urban rail transit system,modern trams have many advantages such as strong economic applicability,humanization and ecology,which has flourished in new areas of large cities and medium-sized cities.As a new type of power supply system,the induction power transmission system has been widely used in low-power charging applications such as mobile phones and electric vehicles.This paper takes the induction power transmission system for modern trams as the research background,research for optimizing operating performance of the system.Different from other applications,modern trams have the characteristics of2M2T100%low-floor,and require high output power and efficiency levels of the power supply system.The installation space under the tram is limited and the power transmission time between the tram and the ground is short,making it difficult to establish a reliable real-time communication.Based on this,this article takes the operating performance of the inductive power transmission system when applied to modern trams as the starting point,with regard to the output power efficiency,the adaptability and performance of the coupling mechanism and the tram,and the dynamic response when the primary and secondary sides have no communication.The key technical issues were verified by building ANSYS(?)electromagnetic simulation model and MATLAB/Simulink(?)circuit simulation model based on actual tram parameters.At the same time,a 1k W low-power experimental platform was built for experimental verification,providing theoretical guidance for the system engineering practice process.Through the analysis of key power efficiency indicators such as the output power,transmission efficiency and power efficiency product of the induction power transmission system,it is found that the system cannot achieve the maximum power and efficiency at the same time.However,the current control strategy is usually optimized for a single goal,and lacks consideration of the system operating status.This paper integrates the two external factors of system coupling coefficient and electric load demand,and proposes a load segment tracking control strategy for different output demands.According to the different coupling coefficient states and power requirements of the system when the tram is charging,the equivalent load is adjusted to track different power efficiency indicators,so that the system always maintains the best power efficiency state under different charging conditions.Optimizes the overall power efficiency performance of the system,which is more flexible than the single-objective optimization.By building a circuit simulation model,the simulation verifies the power efficiency optimization results.In order to improve the performance of the coupling mechanism,the existing design schemes of the coupling mechanism are usually complicated,and are not suitable for occasions where the installation space and location of modern trams are strictly limited.According to the installation space of the coupling mechanism under the modern trams,this paper proposes a configuration method of coupling coils that is suitable for the installation space.Combining the power efficiency characteristics of the previous stage and the requirements of the air gap between the tram and the ground,optimal design of primary turns,secondary turns and their ratio.The mutual inductance level of the coupling mechanism was verified by the electromagnetic simulation model,and the results were introduced into MATLAB/Simulink(?)to verify the system output power efficiency level.At the same time,the design of the coupling mechanism is an optimization problem that requires comprehensive consideration of multiple system objectives.A comprehensive evaluation system for the performance of the coupling mechanism based on the attribute hierarchy method-grey correlation method combined weight is proposed to quantify the influence of basic parameters on the coupling mechanism performance.In order to optimize the dynamic response performance of the system when the primary and secondary side has no communication,complex circuit topology design or control strategy improvement is usually carried out,but it is not suitable for high-power practical engineering applications.This paper proposes a mutual inductance identification method based on parameter sensitivity weights.According to the parameter sensitivity,the weight in the final identification result is determined to improve the identification accuracy.According to the results of mutual inductance identification,an improved variable-step maximum output power tracking algorithm based on disturbance observation is proposed.The system adjusts the disturbance step length when it is close to the maximum power operating point,and performs exponential attenuation according to the Hua Luogeng optimization method to achieve precise tracking.Aiming at the unstable disturbance failure phenomenon caused by the mutation of mutual inductance,a solution is proposed to re-identify the mutual inductance and initialize the disturbance step length when the next disturbance period exits the failure zone.The steady-state accuracy and fast dynamic response performance of the system are verified by simulation.Finally,in order to simulate the operating parameters of modern trams as much as possible.The design of electrical parameters such as voltage and current is reduced in proportion to the high-power basic module to keep the equivalent load of the original side unchanged as the basic principle.Built a small prototype experiment platform with a rated power of 1k W.The coupling mechanism is designed through the optimization of the coupling mechanism in this article,and the feasibility of the optimization scheme and control strategy is verified through the small platform.The experiment verifies that the system maintains a high power transmission level under the target air gap range,while the transmission efficiency meets the requirements,and also verifies the fast response performance and steady-state accuracy in the case of canceling communication.