Chengshi guidao jiaotong yanjiu (Jul 2024)
On-line Monitoring Method for Metro Vehicle Braking Resistor Temperature without Temperature Sensor
Abstract
Objective To achieve real-time temperature monitoring of BR (braking resistor) in metro vehicles without temperature sensor, a new temperature estimation method for this purpose without additional sensors is proposed. Method By analyzing the BR structure and heat dissipation process, a control body temperature model composed of BR unit and its cooling domain is established. Based on the law of energy conservation and Newton′s law of cooling, equations for the temperature of BR unit and the average temperature of the cooling air within the control body are constructed. According to the relationship between braking resistor value and temperature, the BR heating power is continuously updated and iterative calculations are performed to obtain BR real-time temperature. Finite element thermal simulations are conducted to obtain the BR temperature distribution under steady-state and transient conditions, validating the new BR temperature estimation method. Result & Conclusion By calculating BR heating power based on the DC (direct current) traction network voltage and the duty cycle of the chopper circuit, a software-only solution to substitute hardware is achieved, avoiding the need for additional sensors. This method, combined with the BR temperature estimation algorithm, enhances the reliability of BR temperature estimation. The temperature obtained using this new estimation method is consistent with the thermal simulation results based on Fluent software, with relative errors within acceptable limits, proving the effectiveness of the proposed method. The real-time BR temperature estimation method enables BR temperature on-line monitoring and can adjust the electric braking force command values of metro vehicles based on real-time temperature monitoring, thereby improving the reliability and safety of the traction drive system.
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