Optimization of Traction Electric Drive with Frequency Control

Traction motors in electric transport are most often synchronous permanent magnet motors (PMSMs). Induction motors (IMs) have large dimensions and stator current amplitudes under comparable loads. Traditional IM control methods do not solve these problems. Recent studies have shown that by changing the main magnetic flux in the IM in accordance with the load, these characteristics of the asynchronous electric drive can be significantly improved. Standard frequency converters do not allow for the implementation of these algorithms. But it makes sense to conduct a potential assessment of the capabilities of this algorithm to reduce the total stator currents of traction IMs. This article analyzes the results of real tests of a special vehicle for transporting rock inside mines, conducted several years ago at a mining equipment plant and in several mines in Russia. The prototype of the special transport vehicle has a load capacity of 15 tons, and its traction electric drive is based on four motor wheels with a total power of 100 kW and a frequency converter from the company “Vacon” (Vaasa, Finland). The tests were conducted at the plant’s testing ground and in real mine conditions. These tests allowed us to obtain information about the operation of the asynchronous electric drive under dynamically changing loads in a wide range, which is very difficult to obtain on laboratory benches or in industrial enterprise conditions. The experiments confirmed the efficiency of the optimization algorithm for asynchronous electric drives with frequency control. At the same time, the weight, size, and electrical parameters of the drive are as close as possible to those of direct current drives.