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This paper deals with control topologies for modular systems of DC-DC converters. It is possible to connect all converters in parallel, all converters in serial or various combinations. The paper describes possible control topologies for mentioned connections and also describes control topology for reconfigurable control system.
This paper shows modified PWM algorithm for control of the series resonant converter working with the low duty cycle in comparison with standard PWM. Proposed algorithm is used in combination with standard PWM to achieve lowest switching losses in whole output voltage range. The standard algorithm uses basic pulse-width modulation with pulses centered to the waveforms of current. That is disadvantageous,...
Identification of the induction machine substituting circuit parameters is very difficult despite the fact that induction machines are the simplest of all. This is caused by the fact that electrical quantities cannot be measured in the rotor cage. In addition there is proved in the literature, that classical Γ-network includes too much freedom degrees (i.e. 4), therefore it cannot be identified unequivocally...
This article deals with an electromagnetic design of a three phase winding for an induction motor with unusual number of stator and rotor slots (30/22). There are presented two types of windings. The first one is a classic integral-slot winding (m = 3, p = 1, Qs = 30, q = 5, y = 15) and second one is an interspersed winding 1-3-1. This type of winding is very useful for elimination and suppression...
This work deals with the switching losses comparison in hard-switching converter and soft-switching series resonant converter controlled by two different PWM algorithms. The first algorithm uses basic pulse-width modulation and the second one uses modified PWM which is improved at the lower duty cycle regime as shown in the article. The proposed converter shows the ability to switch from resonant...
This article deals with a modeling of a skin effect in rotor bars of an induction motor. Frequency dependencies of rotor resistance and leakage inductance are calculated based on a static model of an induction motor in form of a Gamma-circuit. A skin effect is modeled by a transfer function. There is comparison of transfer function created for theoretical values and for measured one. There is shown...
The paper deals with the design of irregular AC windings by a new method. The new method is based on the notion of “local density of conductors”. Design of the interspersed winding 1–3–1 is shown as an example of using this new method. This type of winding can be used to reduce higher harmonic components of magnetic flux density in the air gap, mainly the fifth and the seventh harmonic. This new method...
The paper deals with identification of the equivalent circuit parameters of the induction motor. The identification has been done by comparison of measured torque and current characteristics and computed torque and current characteristics. Equivalent circuit of the induction motor has been used in form of the Γ-circuit. There is computed the dependency of the leakage inductance and the rotor resistance...
The paper describes a new universal infinitesimal method, which enables the calculation of self and mutual inductances of arbitrary AC windings. The method is based on the notion of the local angular density of conductors n(α) = dN(α)/dα. It will be proved the proportionality B(α)≈ ∫n(α)dα for the magnetic flux density in the air gap. The function n(α) can be arbitrary, i.e. of continual or impulse...
The paper describes a new universal infinitesimal method which enables the analysis and synthesis of arbitrary AC motor windings. The method is based on the notion of the local angular density of conductors n(α) = dN(α)/dα. It will be proved the proportionality B(α) ≈ ∫n(α)dα for the magnetic flux density in the air gap. The function n(α) can be arbitrary, i.e. of continual or impulse character. In...
The paper deals with practical realization of the acceleration method for the torque-speed characteristics measurement of the tree-phase induction motor. Reached results are compared with the characteristics measured on the dynamometer. The authors propose to use B-splines for the processing of measured data Both their application and reached results are shown for the actual case. Further, the authors...
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