Online identification method, device and circuit for leakage reactance of secondary side of transformer

Abstract

The invention provides an online identification method, device and circuit for leakage reactance of a secondary side of a transformer. The secondary side winding of the transformer is connected with aconverter. The method specifically comprises the steps of obtaining a secondary side alternating current voltage of the transformer; obtaining input voltage and input current of the front end of theconverter; calculating a power grid side flux linkage and an alternating current side flux linkage based on the secondary side alternating current voltage and the input voltage respectively; and calculating the front-end inductance of the converter based on the power grid side flux linkage, the alternating current side flux linkage and the input current so as to represent the secondary side leakage reactance of the transformer. The invention also provides the device and the circuit for realizing the online identification method. According to the online identification method, device and circuitfor the leakage reactance of the secondary side of the transformer, the leakage reactance value can be accurately identified, the precision is high, and engineering implementation is facilitated.

Description

technical field [0001] The invention relates to the field of control of power electronic converters, in particular to the on-line identification of the secondary side leakage reactance of the transformer at the front end of the converter. Background technique [0002] Converters, also known as rectifiers and grid-side converters, are connected at one end to the AC power grid and at the other end to the DC circuit, enabling bidirectional flow of energy. They are used in some high-power traction drives, DC transmission, new energy and other fields. , have a very wide range of applications. Especially for electrified railways, as the "heart" of high-power locomotives and EMUs, the core equipment of electrified railways, the performance of high-power traction converters directly affects the running performance of locomotives. [0003] The performance of a high-power traction converter is not only related to its own design and control strategy, but also closely related to the tr...

AI Technical Summary

Problems solved by technology

[0004] Generally speaking, the transformer leakage reactance used in the control is the data provided by the transformer design file, and this leakage reactance value is due to the difference in the manufacturing process, as well as the actual application of the device, due to the Inductance, the actual leakage reactance value may have a certain difference from the nominal value, this deviation will affect the precise control of the grid-side converter, resulting in inaccurate four-quadrant control of the converter, which will affect the locomotive harmonic wave performance

If the error is too large, it will cause a large reactive component in the system, sometimes causing system instability, resulting in abnormal AC current or DC voltage, and in serious cases, it will be out of control, resulting in protection action or damage to the converter

Images