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There are complicated relationships among the radial suspension forces, configuration of windings, permanent magnet thickness and currents in bearingless permanent magnet-type synchronous motors (BPMSM), so researching these relationships has important reference value for designing and optimizing BPMSM. Based on the principle of producing radial suspension forces in BPMSM, the mathematics models of...
The dynamic parameters of a transformer, including its inductances and resistances, are estimated by the application of recursive least squares routine on the measured terminal voltages and currents. The harmonic content of the measured input parameters can be included in the proposed method. The estimation is carried out while the transformer is under load. Therefore, the estimated parameters are...
This paper presents a fast voltage dip detection technique that is suitable for use in a distribution static synchronous compensator (D-STATCOM) in compensating balanced dip and unbalanced voltages in power systems. The proposed voltage dip detection method is based on an efficient least squares algorithm which offers structural simplicity and less computational complexity while maintaining dynamic...
A novel IC-like integration device structure and manufacture process for a thyristor-based capacitor discharging circuit applicable to pulse current generation are studied in this paper. Two structures are compared by means of different design of diode which used as for trigger main thyristor. Substitution of a Zener diode with a p+ n avalanche diode in the equivalent circuit can give more stability...
It is necessary to consider variations of circuit element values for power electronic converter design to satisfy a given specification for a frequency characteristic or a dynamic transient response because the variations of element values generate those of the designed characteristic. Therefore element values and their variation ranges should be designed to give a satisfactory characteristic within...
This paper presents the process of circuit and field coupled finite element (FE) modeling of permanent magnet synchronous motor (PMSM). Compared with traditional centralized parameters model the presented model can consider many effects to the dynamic performance of PMSM, such as the effects of saturation of iron materials, the eddy current, the relative movement of teeth and slots and high-order...
The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic...
With improvement in magnetic property of soft magnetic composites (SMC), electrical machines can be fabricated with more flexible structure at low cost, which results in more options of the drive system design different from the conventional technology, for example, 3D machine structure compared with the 2D structure enforced by the lamination sheets. In this paper, a modular permanent drive system...
In sensorless vector control of induction motor using voltage-fed inverter, the flux estimation error caused by stator voltage error due to the dead time and switch voltage drop and so on can deteriorate the performance of vector control. This paper proposes a method to compensate the stator voltage error by utilizing the error value between the measured current and estimated current. The DC component...
To gain better velocity modulation function and reduce the switch loss, the PWM voltage usually possesses very high frequency and dv/dt in inverter fed induction motor system. The common mode coupling current in the common mode coupling circuit will come into being inside the motor when this style PWM voltage acts on the winding of induction motor. The common mode coupling current component which...
In this paper, using the three-phase induction motor (IM) fifth order model in a stationary two axis reference frame with stator current and rotor flux as state variables, a conventional backstepping controller is designed first for speed and rotor flux control of an IM drive. Then in order to make the control system stable and robust against the parameter uncertainties as well as the unknown load...
Operated under rated conditions, the induction motor (IM) is highly efficient, but the efficiency is greatly reduced with the normal conditions changed. So efficiency optimization has significance for economic saving and environment protecting. This paper summarizes the main efficiency optimization control strategies appearing recently years, and presents a new fuzzy logic based hybrid on-lion minimum...
Ultimo 2006 Danfoss launches the first inhouse-developed micro drive series for the global market. The drive is developed by the Danfoss R&D office in Beijing and manufactured using Danfoss production facilities close to Shanghai. The scope of this paper is to compare the new product with the state-of-the-art of the market
The traditional dynamometers consume more fuel or electric energy while working, so they not only waste energy, but also have lower dynamic performance. An AC variable-frequency power dynamometer scheme is presented based on PWM rectifier and fuzzy direct torque control (DTC) of induction motor in this paper. The dynamometer can operate in both motoring and generating states. The bidirectional flow...
In this paper, a new method based on adaptive radial basis function (RBF) networks is proposed to deal with the issues of rotor position requirement and high torque ripple production in a brushless DC (BLDC) motor. Two RBF networks are trained offline with a self-adjustment growing and pruning (GAP) algorithm, and all the train samples are obtained from experimental results to express the nonlinear...
Motor efficiency evaluation enables the energy savings in industry. However, because of the uninterrupted characteristic of industrial processes, traditional methods defined in IEEE Std-112 cannot be used for these in-service motors. A novel nonintrusive method for in-service motor efficiency estimation based on a modified induction motor equivalent circuit has been developed by the authors. A highly...
This paper presents a kind of simulation software for computing the characteristics of flowing and heat transfer in the stator bars' evaporative cooling system of large hydrogenerators. A model experiment using the real stator bar of Three Gorges' hydrogenerator was introduced also. Under experimental conditions, temperature distributions and utmost thermal load are calculated using the simulation...
A circuit topologies family of single-stage parallel uninterruptible AC/DC converter with high power factor is presented. The topology includes four sections, i.e. full bridge rectifier, parallel converter with power factor correction (PFC), uninterruptible power supply and fast output voltage regulation. The converter has lots of advantages such as: single stage power conversion, uninterruptible...
This paper presents an automatic-current-sharing control method based on average-current mode for parallel boost converters. With the proposed method, the second-order system of the external loop of boost converter is reduced to a first-order in low frequency, which makes the design of the control circuit easy and improves the dynamic response of parallel boost converters. This paper presents detail...
A soft switching converter with parallel-connected full-wave rectifiers is presented. In the proposed converter, the primary windings of two transformers are connected in series. Two full-wave rectifiers with ripple current cancellation are connected in parallel at the output side to reduce the current stress of the secondary winding of transformer. The clamp circuit based on an auxiliary switch and...
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