-
Date submitted2019-03-31
-
Date accepted2019-08-25
-
Date published2020-02-25
Cascade frequency converters control features
The structures of systems with high-voltage cascade frequency converters containing multi-winding transformers and low-voltage low-power converters connected in series at each output phase of the load are considered. Low-voltage blocks contain three-phase diode or active rectifiers, DC capacitor filters, single-phase stand-alone voltage inverters and block disconnecting devices in partial modes (in case of failure when part of the blocks are disconnected). The possibilities of operation of cascade converters are determined, equations for correcting tasks to units in partial modes are given, tables of correction of tasks with estimates of achievable load characteristics are proposed. The results of experiments on the model of a powerful installation with a cascade frequency converter are presented, confirming the possibility of ensuring the symmetry of the load currents when disconnecting part of the blocks and the asymmetry of the circuit.
-
Date submitted2019-05-07
-
Date accepted2019-07-13
-
Date published2019-10-23
Improving the Energy Efficiency of the Electromechanical Transmission of an Open-pit Dump Truck
- Authors:
- A. E. Kozyaruk
- A. M. Kamyshyan
The article analyzes the existing systems of electromechanical transmission of mining trucks BelAZ. The influence of the load nature created by the uncontrolled rectifier on the power factor and mass-dimensional indicators of the electromechanical transmission isassessed. Variants of modernization of the AC-electromechanical transmission system are proposed, which provide power factor correction. The influence of the proposed options on the overall dimensions of the electromechanical transmission is considered. Based on the assessment, a modernization option was chosen that provides the required power factor with minimal impact on the overall dimensions of the electromechanical transmission. The results of modeling the operation of the existing electromechanical transmission and the modernized electromechanical transmission system using the most promising modernization option are presented.
-
Date submitted2018-10-27
-
Date accepted2019-01-04
-
Date published2019-04-23
Application of an active rectifier used to mitigate currents distortion in 6-10 kV distribution grids
The paper addresses issues of using the active rectifier in partially loaded variable frequency drive as active filter in the conditions of non-sinusoidal current and voltage disturbances caused by the presence of high-power non-linear load in the grid. The topology of transformless three-level converter for 6-10 kV suitable for proposed solution has been presented and its mathematical model has been de-rived. Based on the model, the direct power control algorithm with ability to compensate non-linear currents has been designed. The investigation of active rectifier efficiency was performed depending on the relation between linear and non-linear load currents of the grid node, as well as on active power load of the active rectifier. Efficiency analysis was based on the developed computer model of the grid node with connected non-linear load simultaneously with the variable frequency drive with active rectifier.
-
Date submitted2010-07-26
-
Date accepted2010-09-14
-
Date published2011-03-21
Algorithm of control of the electric drive with ventilniy electric motor and the converter of frequency with the active rectifier
- Authors:
- A. P. Emelyanov
- A. O. Sviridenko
Advantages of application of the active rectifier as a part of converters of frequency for powerful drives with ventilniy electric motors are considered. The mathematical description of the processes proceeding in a power part of the active rectifier is given. The scheme of a drive with a vector control system with the gage of position of a rotor and the active rectifier is presented, schedules of power consumption and a current by a drive with the active rectifier are resulted.