A reliable and accurate calculation of excitation capacitance value for an induction generator based on interval computation technique

Abstract

A squirrel cage induction generator (SCIG) offers many advantages for wind energy conversion systems but suffers from poor voltage regulation under varying operating conditions. The value of excitation capacitance (Cexct) is very crucial for the selfexcitation and voltage build-up as well as voltage regulation in SCIG. Precise calculation of the value of Cexct is, therefore, of considerable practical importance. Most of the existing calculation methods make use of the steady-state model of the SCIG in conjunction with some numerical iterative method to determine the minimum value of Cexct. But this results in over estimation, leading to poor transient dynamics. This paper presents a novel method, which can precisely calculate the value of Cexct by taking into account the behavior of the magnetizing inductance during saturation. Interval analysis has been used to solve the equations. In the proposed method, a range of magnetizing inductance values in the saturation region are included in the calculation of Cexct, required for the self-excitation of a 3-φ induction generator. Mathematical analysis to derive the basic equation and application of interval method is presented. The method also yields the magnetizing inductance value in the saturation region which corresponds to an optimum Cexct(min) value. The proposed method is experimentally tested for a 1.1 kW induction generator and has shown improved results.

Analisis Tegangan Keluaran Generator Listrik Frekuensi Rendah dengan Metode Conjugate-Gradient

“…Dimensi kumparan dan besarnya medan magnet pada sebuah generator serta besarnya kecepatan pergerakan di antara keduanya dapat dibuat bervariasi berdasarkan kebutuhan daya listrik yang diinginkan [3]. Fenomena tersebut memerlukan analisis yang tepat untuk menghasilkan sebuah generator yang efektif dan efisien dalam menghasilkan arus listrik [8][9][10]. Metode yang selama ini dikembangkan dalam perancangan generator listrik adalah ekperimen.…”

“…Pada referensi tersebut, digunakan magnet permanen (B) sebesar 1,0833 Tesla (0,0002 Weber), luas penampang (A) sebesar 2 cm 2 , dan sudut antara medan magnet dan momen magnet () sebesar 45 o . Jumlah lilitan sebanyak 63 dengan tegangan keluaran sebesar 12 Volt yang dibangkitkan dengan kecepatan putaran 500 rpm (revolution per minute) [2,3,9]. Jumlah lilitan berdasarkan perhitungan komputasi berada pada angka yang hampir sama dengan ekperimen pada referensi [2,3,9], yaitu pada kisaran 60.…”

“…Jumlah lilitan sebanyak 63 dengan tegangan keluaran sebesar 12 Volt yang dibangkitkan dengan kecepatan putaran 500 rpm (revolution per minute) [2,3,9]. Jumlah lilitan berdasarkan perhitungan komputasi berada pada angka yang hampir sama dengan ekperimen pada referensi [2,3,9], yaitu pada kisaran 60. Tabel 2 merupakan pengembangan metode perhitungan pada Tabel 1 dengan parameter standar yang sama.…”

Determination of Excitation Capacitance of a Three Phase Self Excited Induction Generator

“…This is widely used in isolated wind power generation schemes. The magnetizing inductance value in an induction machine is a function of rotor speed and is non linear [1]. Therefore a range of capacitance value is required so that the machine is in excitation mode and the generator terminal voltage is within the limits.…”

Three-phase self-excited induction generator analysis in stand-alone mode

“…Fo reliability, many wind power systems use in driven by a wind turbine through a gearbo generator. [5,6] Thanks to its many advantages suc ruggedness, inherent self-protection against o circuit faults, together with its ability to g various speeds, the induction machine is wi strongly present in wind energy conversion ap In case of a grid-connected mode, the in can draw a reactive power from the grid. For there must be a suitable capacitor bank con generator terminals.…”