Control method for starting cooling fan motor of railway locomotive

Abstract

A motor starting control method for a cooling fan of a railway locomotive. A target value of an output frequency of an inverter is set as a relatively low value F1, the output frequency of the inverter is controlled according to a relatively low loading rate Rp1, and when the output frequency of the inverter reaches F1, F1 is maintained till time T1. From starting time to T1, a lower value between two closed-loop control output values, namely an output current limit and an intermediate DC voltage limit, is multiplied by a modulation degree Mi to obtain a new modulation degree ML, and an output voltage of the inverter is controlled, such that an output current is limited within a given maximum starting current range, and an intermediate DC voltage is limited within a DC voltage limit value range. At T1, the target value of the output frequency of the inverter is set as a relatively high value F2, the output frequency of the inverter is controlled according to a relatively high loading rate Rp2, and F2 is reached at time T2. The method enables a fan motor to be started stably at any initial rotating speeds and in any rotating directions, and prevents an inverter from an exceeded intermediate voltage.

Description

technical field [0001] The invention relates to a motor starting control method, in particular to a motor starting control method for a cooling fan of a railway locomotive, belonging to the technical field of railway locomotives. Background technique [0002] With the rapid development of power electronics technology, the application of converters is becoming more and more extensive. In the field of industrial control, converters are often used to drive fan motors to achieve precise fan motor speed control. However, in the application of railway locomotives, due to the constraints of cost and installation space, the shaft head of the cooling fan motor cannot be installed with a speed encoder. In many cases, when the converter starts, the fan motor already has a high initial speed, and its direction of rotation is uncertain. If the inverter outputs three-phase alternating current to the cooling fan motor at a certain frequency and voltage rise rate from the very beginning, t...

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Problems solved by technology

If the converter outputs three-phase AC power to the cooling fan motor at a certain frequency and voltage rise rate from the very beginning, it will cause excessive starting current of the motor, which will bring vibration and shock to the mechanical and electrical systems, and even trigger overheating. flow protection, affecting the reliable operation of the system

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