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The maximum torque per ampere (MTPA) control has been widely employed to improve the efficiency of the permanent-magnet synchronous machine (PMSM) drive systems. To achieve accurate online MTPA tracking, in this work, a high-frequency current injection based method is proposed. Compared to the lookup-table based MTPA control, the proposed method can significantly reduce the pre-tuning effort. Since...
Salient pole wound field synchronous machines (WFSMs) share similar torque characteristics as permanent magnet (PM) machines, but are free of permanent magnet material since a wound rotor winding instead generates the required field flux. In addition to cost advantages, the rotor field flux is readily varied making these machines attractive for traction and generator applications. This paper introduces...
When direct torque control (DTC) is applied to permanent magnet synchronous motor (PMSM) drives, the relationship between the torque and stator flux linkage is important for high-efficiency drives because DTC requires them as references. In the stator flux linkage synchronous frame (M-T frame), the torque is described by a simple equation using the T-axis current. However, the M-axis current is neglected...
For maximum torque control of induction machines (IM) in flux-weakening region, the following problems exist: 1. In Volts/Hz scalar control mode, a slow frequency ramp time cannot provide sufficient electromagnetic torque, whereas the excessive acceleration leads to overcurrent shutdown and system collapse; 2. In vector control mode, the under-estimated leakage inductance in field-weakening region...
Computational burden is a major hurdle for practical implementation of finite-state predictive torque control (FS-PTC) of motor drive fed by a multi-level inverter. One of the reasons of computational complexity is that all voltage vectors are evaluated for prediction and actuation. This paper proposes selected number of voltage vectors for the prediction and actuation, which are called prediction...
The AHU (air handler unit) is one of the main research objects in HVAC (heating, ventilating and air conditioning) system containing coils, blower wheel, heater, etc. Most of the high efficiency blower wheels are driven by BLDC (brushless DC) motor. This paper mainly focuses on two severe problems in blower wheel, namely airflow blockage and unbalanced load of fan motor. Early diagnosis of these problems...
This paper presents an approach to implement the universal flying restart for an induction machine using a frequency search algorithm that determines the rotor speed so that the correct frequency and voltage can be applied to minimize the inrush current during the restart. This method only uses the measured phase current and the motor nameplate parameters, thus making it ideal for use with scalar-controlled...
This paper considers the possibility of adopting a conical shaped motor for Green Taxiing (GT) application. This topology of motor has been selected in order to obviate the presence of external declutching system (i.e. mechanical or electromagnetic clutch) interposed between the electric actuator and the wheel. An axial force contributes to move the rotor inside-out of the stator (principle of sliding-rotor)...
Motor current signature analysis (MCSA) has recently become widespread in industry for on-line detection of rotor cage faults in induction motors for preventing forced outages. Although it can provide low cost, remote monitoring of rotor faults, cases of false indications have been reported, where the causes of some false indications are still unknown. It is shown for the first time in this work that...
Model predictive current control uses a model of the machine and an appropriate cost function to indirectly control electromagnetic torque and reactive power. However, due to sensitivity of model predictive control (MPC) to system parameters, need for high sampling frequency, and high torque and flux ripples, this method is not employed in a wide variety of commercial drives. Incorporating the concept...
Doubly fed induction generators are presently used in the large majority of high power wind turbine applications. The current doubly-fed induction generator technology specifies that the turbine operates sub-synchronously to follow the desired power vs. wind speed profile and to operate super-synchronously only during brief periods where wind gusts exceed the nominal maximum value of thrust. This...
This paper investigates the dynamic stability of a droop-controlled multi-generator system in the more electric aircraft (MEA). Based on the developed state-space model of the potential dc electrical power system (EPS) architecture, the stability boundaries of EPS operation depending on parameter variations including component parameters and operating conditions are investigated. The effect of multiple...
This paper proposes a control scheme for the wide operation range of an induction generator (IG) with a Vienna rectifier. A Vienna rectifier has the limited operation range because the sign of the current should be the same as that of the voltage in the normal operation. For this reason, the power factor of a Vienna rectifier is also limited. In the IG, the d-axis stator current is necessary for the...
Electromagnetic acoustic noise from electrical machines has increasingly become an area of attention for both academia and industry. In electric propulsion systems, this is a main contributor to the total acoustic noise and it is usually perceived as annoying due to its tonal appearance. This paper presents an alternative rotor design for a permanent magnet synchronous machine with the objective to...
Gearbox faults are a leading reliability issue in wind turbines. Generator current-based methods have been successfully used in gearbox fault diagnosis and have shown advantages over the traditional vibration-based techniques in terms of implementation, cost, and reliability. This paper proposed a new generator stator current-based fault diagnostic method for the gearboxes in doubly-fed induction...
This paper proposes a rotor tooth shaping method to reduce the cogging torque of an axial flux-switching permanent magnet machine. The rotor tooth is shaped in different configurations, including constant, trapezoidal, asymmetrical, extended, and square shapes. 3-D finite element analysis is performed to compare the proposed shapes of rotor tooth. Peak-to-peak cogging torque, fundamental flux linkage,...
In typical traction Electric Vehicle applications, the DC-link voltage varies during transient accelerating and decelerating process in field-weakening region. The calculated reference voltages of current PI regulators tend to be larger than the one in steady state, which will result in the undesired flux-producing current oscillations. This further deteriorates the electromagnetic torque performance...
The determination of induction machine torque and current speed characteristics relies on methods based on either direct testing or calculation, using machine equivalent circuit. Both methods may lead to significant errors. The paper discusses the challenges encountered using these methods and an approach is presented in the paper to overcome the inherent challenges. The proposed approach considers...
This paper presents an analytical model, for a new spoke type variable flux machine, with AlNiCo magnets, in the no-load condition. This method is based on the solution of a simple magnetic equivalent circuit of spoke type machines. The effect of stator slots on the air gap magnetic flux density is studied and uneven air gap length is modeled. Based on the no-load air gap magnetic flux density, the...
Lately, a new diagnostic mean has been introduced for reliable fault diagnosis in delta-connected induction motors. This diagnostic mean is the zero-sequence current frequency spectrum. It will be shown in this paper that, the zero-sequence current waveform can be reliably used for identifying the induction motor's iron core saturation level. So in this work, simulations with the Finite Element Method...
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