Method for suppressing intermediate voltage oscillation of traction main circuit and traction main circuit

Abstract

The invention discloses a method for suppressing the oscillation of the intermediate voltage of the traction main circuit, comprising: S01, when the train is in the working condition of traction or coasting, collecting the voltage value U of the intermediate capacitor c and the voltage value U of the traction power supply network d , and get the difference △U cd , and U c rate of ascent dU c / dt; S02, when △ U cd ≥△U cd1 and dU c / dt≥dU c1 / dt, it is judged that resonance occurs, and the connection between the traction main circuit and the traction power supply network is disconnected; S03, when △U cd ≤△U cd2 , the connection is restored. The invention also discloses a traction main circuit, which includes a control unit, an intermediate capacitor, an inverter module, and a first voltage detection part for detecting the voltage value of the traction power supply network, and a switch unit is connected in series between the DC voltage terminal and the intermediate capacitor , the intermediate capacitor is connected in parallel with a second voltage detection element for detecting the voltage value of the intermediate capacitor, and the control unit controls the action of the switch unit according to the detection values ​​of the first voltage detection element and the second voltage detection element to suppress oscillation. Both the method and the traction main circuit of the invention have the advantages of effectively suppressing oscillation and the like.

Description

technical field [0001] The invention mainly relates to the technical field of rail transit, in particular to a method for suppressing the oscillation of the intermediate voltage of a traction main circuit and the traction main circuit. Background technique [0002] Such as figure 1 It is a typical main circuit of a traction system, including high-speed circuit breaker HB1, charging and discharging units (KM11, KM21 and pre-charging resistor R11), reactor L1, intermediate capacitor C1, inverter and traction motor. figure 1 Simplified as figure 2 As shown, the reactor L1 and the intermediate capacitor C1 in the traction system are mainly used as filters to filter out high-order harmonics, so that the input voltage of the inverter is stable, and the output torque of the motor is controlled by controlling the output of the inverter. The stability of the inverter input voltage plays an important role in the control of the inverter. If the inverter input network voltage is unst...

AI Technical Summary

Problems solved by technology

The stability of the inverter input voltage plays an important role in the control of the inverter. If the inverter input network voltage is unstable, it will affect the output of the inverter.

Due to the existence of the LC circuit, the circuit has an inherent oscillation frequency. Once the front-end network voltage input has the same frequency oscillation, the intermediate voltage of the intermediate capacitor C1 will resonate with the network voltage, which will eventually affect the inverter output, such as image 3 shown (where image 3 The grid voltage waveform diagram is at the top, and the DC waveform diagram is at the bottom), causing overcurrent and other faults and affecting the normal operation of the train

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