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Condition monitoring of inverter-fed drives is gaining a more important role. Inverter operation enables maximum utilization of a drive. However, some parasitic phenomena may occur, e.g. bearing currents, temperature increase due to additional losses and stress caused by fast voltage rise times. With focus in this work on stator winding insulation an online monitoring method is presented to detect...
The demand for AC machines in traction applications fed by voltage source inverters is increasing. These highly efficient drives working near and even above their rated values are expected to operate for many years or even decades. Thus, condition monitoring is gaining a more important role. With focus in this work on outages due to deteriorated machine winding insulation an online monitoring method...
Insulation condition monitoring is important in case of inverter-fed machines due to the high strains on the machine and especially on its winding insulation system. In particular in traction applications the usage of new emerging semiconductor technologies, which enable higher inverter switching frequencies and rapid voltage rises, transient overvoltages at the machine occur. The insulation system...
In order to investigate insulation degradation of high voltage traction drives, series of measurements on form wound coil specimens have been done. These stator bars have been aged by different accelerated aging cycles until the failure of the insulation is determined by voltage exposure tests. After every aging cycle the dissipation factor (tan δ) and capacitance (C) of the insulation system is recorded...
In this work a method to detect stator insulation degradation of traction drives based on analyses of the transient current reaction caused by inverter switching is proposed. Two simple excitation methods are proposed to analyze the state of the inter-turn insulation as well as the groundwall insulation. With the standard hall-effect based closed loop current transducers used for the control of the...
Industrial application of adjustable speed drives (ASD) has been constantly growing in the last decades. In addition to the sheer number of inverter-fed drives the variety of application fields is increasing too. The use of such ASD in safety critical devices or industrial systems with many drives installed leads to the requirement of increased reliability. Furthermore many drives are operated at...
Adjustable Speed Drives (ASD) are the favorable choice in a fast increasing scope of applications. Although generally highly reliable, continuous condition monitoring of electrical drive systems becomes more and more important, as the adoption of such systems in safety critical applications, like x-by-wire and in the so called more electric aircraft, increases. To fulfill the demand of high efficiency...
Modern electrical drive systems basically consist of three components determining its complex impedance system - the inverter, the cabling and the machine itself. For high efficiency and good return on investment these components are operated at or near their rated values. Furthermore stress is added due to high dynamic operation, transient overload and the very fast switching of modern power electronics...
This paper analyzes a new method for detecting defective rotor bars at zero load and standstill by means of modeling using the finite element method (FEM). The detection method uses voltage pulses generated by the switching of the inverter to excite the machine and measures the corresponding reaction of the machine phase currents, which can be used to identify a modulation of the transient leakage...
The electrical part of modern drive systems usually consists of different components like power electronics, cabling, windings. Each of these components is usually operated at or near its rated values. In addition, high dynamic operation, overload cycles, as well as the fast switching of the power devices puts additional stress on all drive components. As a consequence overall reliability is reduced...
In comparison to rotor bar fault detection for mains fed induction machines the detection in inverter-fed drives is especially challenging. The most important reasons are the disturbances introduced by the fast switching of the inverter. Moreover the fault indicator is influenced also by control dynamics and load changes. In addition most known fault detection technologies need a certain load level...
Inverter-fed induction machines are permanently excited by the switching of the power electronic devices. Machine design and high-frequency material properties influence the transient electrical behavior which is not only important for the design of the machine, but can also be exploited for sensorless control methods for induction machines. To enable a simulation of this influence, a model has been...
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