Three-closed-loop control method for DC electronic load limiting rail voltage

Abstract

A three-closed-loop control method for DC electronic load limiting rail voltage comprises the step of performing three closed-loop control on a non-isolated DC step-down electronic load device, wherein the outermost loop adjusts the rail voltage by a variable step disturbance control algorithm, the intermediate loop outputs voltage control through a Buck converter, and inner loop is inductor current control. By adding an electronic load device for rail energy consumption on the rail, the method provided by the invention realizes stepless adjustment of an equivalent input resistance R resistance value of the electronic load device under the rated power condition through the three-closed loop control of the electronic load device, so as to consume the end energy of the rail, reduce the voltage at the source end, realize the terminal voltage to control the voltage of the source terminal, and stabilize the source voltage to a safe value. The control method adopted by the invention can effectively control the output of energy on the rail, realize the rail voltage control through the equivalent resistance to the energy consumption of the source end, and make the rail voltage approach thereference value at an optimal rate and maintain the safe range.

Description

technical field [0001] The invention relates to a method for limiting rail voltage, in particular to a three-closed-loop control method for limiting rail voltage, and belongs to the technical field of rail voltage limitation. Background technique [0002] In recent years, with the development of urban rail transit, rail potential rise has become a common problem in subway operation. Aiming at the rail potential problem, the traditional DC traction power supply system solution is to install the rail potential limiting device OVPD at the station, one end is connected to the running rail, and the other end is connected to the system ground grid. The device detects the rail potential in real time. Under normal conditions, the contacts of the DC contactor are disconnected; under abnormal conditions, that is, when the OVPD detects that the rail potential exceeds a given value, the OVPD closes for three stages. The three-stage voltage protection system controls the short-circuit d...

AI Technical Summary

Problems solved by technology

When it was put into use, it was found that there were some problems with the rigid grounding method. A large amount of stray current would be generated during the control process, and frequent grounding of protection actions would easily occur, causing the potential of the rail to fluctuate back and forth, and at the same time reversed the distributed inductance of the line The peak voltage and the oscillation amplitude reach hundreds of volts, which has a great impact on the DC traction power supply system, and in severe cases, electric sparks will occur

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