An Improved Torque and Current Pulsation Suppression Method for Railway Traction Drives Under Fluctuating DC-Link Voltage

Railway Traction Drives

ABSTRACT:  

For railway traction drives, the dynamic front end typically receives a solitary stage rectifier. Be that as it may, the dc-interface voltage of this single-stage rectifier contains a second-arrange fluctuating part because of the variance of the immediate power at both the air conditioner and dc sides. Encouraged by the fluctuating dc-interface voltage, the footing engine experiences serious torque and current throb. The equipment arrangement with an extra LC thunderous channel is basic, yet it will lessen the power thickness of the framework.

An elective arrangement is to wipe out the beat part in the stator voltage/current through tweak proportion or recurrence remuneration. Notwithstanding, it is hard to accomplish superior for the customary feed forward technique. In this paper, an enhanced shut circle torque and current throb concealment technique is proposed, which can wipe out the q-pivot current throb part in the field-arranged control framework through recurrence pay. The torque throb concealment is additionally accomplished consequently. Recreation and test results demonstrate that the proposed plan can successfully lessen the torque and current throb in different activity modes contrasted and the ordinary feed-forward strategy.

 

CIRCUIT DIAGRAM:

Fig. 1. Circuit schematic of the ac/dc/ac traction drive system.

 

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation results of two methods in the asynchronous modulation mode. (a) Line voltage of the motor. (b) and (c) Stator current and torque with the conventional method. (d) and (e) Stator current and torque with the proposed method. (f) DC-link voltage of the inverter without and with the proposed method. (g) Transition waveforms of the stator current without and with the proposed method.

Fig. 3. Spectrum analysis of the simulation results of the two methods in the asynchronous modulation mode. (a)–(c) Stator current without compensation, with the conventional method, and with the proposed method. (d)–(f) Torque without compensation, with the conventional method, and with the proposed method.

Fig. 4. Simulation results of the two methods in the synchronous modulation mode. (a) Line voltage of the motor. (b) and (c) Stator current and torque with the conventional method. (d) (e) Stator current and torque with the proposed method.

Fig. 5. Simulation results of the two methods in the square-wave modulation mode. (a) Line voltage of the motor. (b) and (c) Stator current and torque with the conventional method. (d) and (e) Stator current and torque with the proposed method.

CONCLUSION:

A shut circle torque and current throb concealment technique for Railway Traction Drives under fluctuating dc-interface voltage is proposed. This technique means to dispense with the q-hub current throb part in the FOC framework through yield recurrence remuneration. The torque throb concealment is accomplished based on q-pivot current throb end naturally. A thunderous controller is proposed for the shut circle control of q-hub present and dynamic pay of the yield recurrence. Unique in relation to the regular feed forward open-circle recurrence pay strategy, the torque throb with the proposed technique is smothered through the disposal of the q-hub current throb part instead of the beat segment in the yield voltage.

The viability of the proposed technique have been confirmed by recreation and analyses on footing drives with the inverter worked in non-concurrent, synchronous, and square wave regulation modes, separately. The outcomes have been contrasted with those with the customary feed forward recurrence pay technique dependent on fluctuating dc-connect voltage recognition. Both reenactment and test results demonstrate that the concealment of stator current and torque throb are evident in various regulation modes with the proposed control technique utilizing a similar dc-interface capacitance. The proposed concealment strategy can diminish the affect-ability of the framework to varieties of the matrix recurrence. Be that as it may, the fluctuating segment in the dc-connect voltage will be expanded with the proposed strategy contrasted and the LC resounding channel arrangement.

 

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