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The basic spatial modulation effects of induction machines caused by slotting and saturation, have been analyzed for exploitation in speed sensorless control. With increasing load level, additional spatial harmonics arise, acting as disturbance and deteriorating sensorless control performance. In view of the fact, that induction machines for application in traction systems (e.g. public or cargo transportation)...
Equivalent circuit parameters are very important for permanent magnet synchronous machines since they serve as the basis for performance estimation and implementation of power electronic drives controls. Specified in the newly approved IEEE Std 1812, a short-circuit test can be employed, in combination with an open-circuit measurement, in order to determine the back emf and the synchronous inductance...
Current derivative based sensorless control methods, which falls under saliency tracking technique, is a promising new sensorless control methods for AC machines over a wide speed range, including zero speed. This method requires accurate current derivative measurement under different applied PWM voltage vectors. The accuracy of current derivative is affected by the high frequency oscillations which...
Efficiency of induction machines can be determined using international efficiency test standards such as the IEEE standard 112, IEC 60034-2-1 and JEC 37. The methods presented in these standards involve tests such as the no-load test, lock rotor test and a dynamometer test. Performing the no-load test is simple with fewer requirements in terms of equipment. The dynamometer test and the locked rotor...
The paper analyzes the capability of synchronous reluctance generators to achieve successful self-excitation when operating in stand-alone systems. To initiate the self-excitation process, the machine steel core has to retain sufficient residual flux during the generator start-up. This residual flux depends on the magnetic properties of the machine core as well as the previous machine operating condition...
This paper presents a method of position and speed estimation technique for a four-phase switched reluctance machine with novel bridge converter. The phase inductance is measured by high frequency voltage injection in an idle phase which is opposite to energized phase and the inductance variation is maximum. The two order Fourier series is used to match the phase inductance with rotor position. The...
Precise control methods of the electric drives with induction machines like field oriented control (FOC) or direct torque control (DTC) need an accurate model of the machine they control. Certain parameters of the model have to be obtained with sufficient accuracy before the drive can be put into the operation. This article concerns an offline parameter identification method that is suitable for on-site...
The goal of this paper is to investigate the influence of the rotor geometry and the contribution of a small amount of PM in the fundamental-frequency-based electromechanical position estimation of synchronous reluctance motors. The analysis is carried out by means of the sensitivity analysis, which allows to consider the effects of both parameter mismatches and measurement errors on the position...
The paper deals with brushless DC motors (BLDC) operated in high speed region without any speed or position sensor. A six-step commutation technique is used to control the BLDC motor, utilizing the disconnected motor phase for sensing the induced voltage. The main goal of the paper is to describe the limitation of the conventional 6-step commutation control in sensorless mode at high speeds and to...
In the paper the design of an IPMSG for small wind turbines is presented. Based on classical construction of induction motor (IM), the internal permanent magnet generator (IPMG) was projected. Parameterization and sweep analysis of the rotor geometry was done in the finite element analysis (FEA) software, to obtain the maximum back electromotive force (BEMF). Based on this analysis, one case was chosen...
This paper presents a sensorless starting procedure for a soft starter driven IE4 direct on line permanent magnet synchronous motor (PMSM). First, the initial position of the rotor is determined using a pulsating current space vector. Subsequently, the motor is started from standstill by the soft starter from a known position. The following firing sequences are calculated on the basis of the flux...
The paper presents the possibility of using a two-dimensional field-circuit model of a squirrel cage induction motor for qualitative tests of the axial leakage flux course used in non-invasive diagnostics of induction machines. The study considered the reduction of leakage fluxes associated with the stator and rotor winding to the zero component of the symmetric components system. A qualitative comparison...
The failure rate of doubly-fed induction generators (DFIG) for wind turbine generations was relatively higher than that of direct-driven generators, according to statistical data from some wind power industries. The rotor insulation was a relatively weak part of the insulation system for DFIG because it was normally subjected to a PWM impulse voltage during the long-time operation. In this paper,...
This paper investigates the harmonic voltage control strategy of direct torque control for five-phase induction generator (IG) system. In high/medium power applications, the generating function requires the performance of fast dynamic response, good static performance and high utilization of the dc bus voltage. For IG generating system, the direct torque control strategy has the advantages of easy...
This paper proposes a novel technique to estimate online the inductances of a Permanent Magnet Synchronous Machine (PMSM) based on the measurement of the current derivatives excited by two active-voltage vectors and one zero-voltage vector within a PWM cycle. The d- and q-axes inductances of PMSMs are calculated during normal operation of the drive system. The influence of the magnetic saturation...
This paper presents a sensorless control method for IPMSMS drives over a wide speed range operation, including zero speed. The rotor position estimation of this method is based on relating the measured current derivative response which excited from fundamental PWM sequences to the incremental inductance. Compared to other saliency tracking sensorless control schemes, this method doesn't require additional...
This paper examines several techniques for determining the parameters of the Brushless Doubly Fed Reluctance Machine (BDFRM). Even though the mathematical model for this machine is like that of a double-fed induction machine, the very high leakage inductances prevent the use of the normal locked rotor/unloaded rotor tests. The accuracy of the parameters found is validated by machine testing and comparison...
Recently, there has been a lot of researches on various methods for a sensorless control of permanent magnet generators (PMG) in wind turbines. The sensorless control of the PMG considers estimations of a rotor angle and speed which are based on the PMG parameters estimation. The parameters that have been estimated are stator resistance, rotor flux, d-axis and q-axis inductance. For more precise rotor...
This paper presents a novel algorithm for speed and position estimation of Permanent Magnet Synchronous Machine (PMSM). The developed sensorless control scheme is based on a simple implementation of sliding mode observer (SMO) employing the modified PMSM mathematical model. All PMSM variables are expressed in an arbitrary rotating frame. Initially the modified rotor flux is calculated through measuring...
This paper discusses the problem of a sensorless control method for permanent magnet synchronous machines named Direct Flux Control (DFC). Direct Flux Control provides its users with the angle of the total flux in the machine at all working points, including standstill. The Direct Flux Control signals are a mirror for the current inductivity and flux distribution in a permanent magnet synchronous...
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