A feedback control method and system based on pwm regenerative converter

Abstract

The invention discloses a feedback control method and system based on a PWM energy-feedback converter. The method includes: the DC side of the PWM energy-fed converter is connected to the DC catenary, and the AC side is connected to the AC grid through a transformer; detecting the DC catenary voltage within a continuous time t; calculating the DC catenary voltage change slope k; comparing the DC catenary The voltage change slope and the preset conditions of the control system determine the system working condition; if the preset system working condition is met, and the voltage value reaches the set threshold, the PWM energy-feeding converter is put into operation. The system includes: an energy-feedback converter access device, a voltage detection device, a slope calculation device, a working condition judgment device, and a feedback adjustment device. The invention can accurately judge the running state of the train through the change of the DC catenary voltage, solves the problem of stability and reliability in the engineering application of the PWM converter, thereby controlling the accurate input of the PWM rectifier, and achieving the purpose of energy saving in the power supply system , the criterion is simple and accurate.

Description

technical field [0001] The invention relates to the technical field of urban rail transit power supply, in particular to a feedback control method and system based on a PWM energy-feedback converter. Background technique [0002] In the existing urban rail transit power supply system, diode rectifiers are generally used as the power supply for trains. Diode rectifiers have the advantages of high efficiency, large capacity, strong overload capacity, etc., but also have disadvantages such as uncontrollable output voltage, large ripple, and unidirectional energy flow that cannot be used for regenerative braking energy absorption and utilization. When the train starts to run, the diode rectifier rectifies the work to provide traction energy to the train. When the train brakes, it is in the braking power generation mode, the DC bus voltage rises, the catenary voltage fluctuates within a certain range with the change of the train load on the catenary, and the PWM changes. The cur...

AI Technical Summary

Problems solved by technology

Diode rectifiers have the advantages of high efficiency, large capacity, and strong overload capacity. At the same time, they also have disadvantages such as uncontrollable output voltage, large ripple, and one-way energy flow that cannot be used for regenerative braking energy absorption and utilization.

However, the PWM converter is easy to cause misjudgment, and forms a power circulation with the diode rectifier unit, making it difficult to accurately judge the running state of the train, which is not conducive to the energy utilization of the track power supply system

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