102 IPTEK, The Journal for Technology and Science, Vol. 22, No. 2, May 2011 Thermal Analysis on Radial Flux Permanent Magnet Generator (PMG) using Finite Element Method Pudji Irasari 1 , Hilman Syaeful A 2 , and Muhammad Kasim 1 AbstractThe main source of heat in the permanent magnet generator (PMG) is the total losses which f come from winding losses, core losses and rotational losses. Total heat arising from such these losses must be properly distributed and maintained so as not to exceed the maximum allowable temperature to prevent damage to insulation on the winding and demagnetization on the permanent magnet machines. In this research, we consider thermal analysis which is occurred on the radial flux PMG by using finite element method to determine the extent to which the heat generated can be properly distributed. The simulation results show that there are no points of heat concentration or hot spot. The simulation maximum temperatures of the permanent magnet and the winding are 39.1 o C and 72.5 o C respectively while the experimental maximum temperature of the winding is 62 o C. Keywordsgenerator, permanent magnet, radial flux, temperature, finite element methode AbstrakSumber utama panas dalam generator magnet permanen (GMP) adalah rugi-rugi yang terdiri dari rugi lilitan, rugi inti dan rugi rotasional. Panas total yang timbul dari rugi-rugi tersebut, harus terdistribusi secara merata dan dijaga supaya tidak melebihi temperatur maksimum yang diizinkan untuk mencegah kerusakan isolator pada lilitan dan demagnetisasi pada mesin magnet permanen. Dalam penelitian ini telah dilakukan analisis termal pada GMP fluks radial menggunakan metoda elemen hingga untuk mengetahui sejauh mana panas yang ditimbulkan dapat terdistribusi secara merata. Hasil simulasi menunjukkan bahwa tidak terjadi titik konsentrasi panas atau hotspot dalam generator. Temperatur maksimum magnet dan lilitan hasil simulasi adalah 39.1 o C dan 72.5 o C sedangkan temperatur maksimum hasil eksperimen pada lilitan adalah 62 o C. Kata Kuncigenerator, magnet permanen, fluks radial, temperatur, metoda elemen hingga I. INTRODUCTION7 emperature rise is caused by the operation of rotating machines is merely an unavoidably natural phenomenon. Related to the temperature rise problem, for a designer an important thing that needs to be considered is how to distribute and reduce the heat so that overheating will not occur. A design analysis therefore focusing on the thermal aspects becomes very important to be ignored in which it provides the existency a certain requirement in which thermal condition must be maintained within the permitted operational limits. An analysis upon temperature distribution is highly necessary to ensure there is no heat concentration point or hotspot that might cause damage to the isolator on the winding or demagnetization on the permanent magnet [1, 2]. The method for thermal analysis is basically divided into two, i.e. analytical lumped-circuit (thermal circuit) and numerical method. The method of analytical approach has its own advantage on the faster speed of its computation; nevertheless its circuit modeling demands higher accuracy in order that distribution path for the heat to transfer can be precisely determined. 7 Pudji Irasari is with Department of Research Center for Electrical Power and Mechatronics, Indonesian Institute of Sciences, Bandung, 40135, Indonesia. E-mail: pudj002@lipi.go.id Hilman Syaeful A, and Muhammad Kasim are with Department of Technical Implementation Unit for Instrumentation Development, Indonesian Institute of Sciences, Bandung, 40135, Indonesia. The method of numerical analysis holds its own advantage due to its capability in modeling all geometrical objects. However, it takes longer time in both establishing the model and running the computation. Two types of numerical analyses are currently in existence, i.e. finite-element analysis (FEA) and computational fluid dynamics (CFD). CFD is more advantageous because once it is used it can predict the flow in a complicated area, e.g. around the end winding of a motor/generator. On the other hand, FEA can only be utilized for modeling conduction heat transfer on solid components [3]. A thermal analysis on electric machine (motor and generator) using finite element method has been conducted by some research. Mahadi studied linear generator for automotive and stand-alone (standby or remote) generator applications. The effect of heat (generated from combustion engine, current carrying conductors and friction) on the performance of NdFeB magnet was examined with and without cooling fins [4]. In [5], heat transfer of 600W and 60 kW switch reluctance motors (SRMs) was investigated. The heat transfer mechanism of 600W SRM was done by natural convection; while for 60 kW SRM the analysis was carried out using copper pipe with water as a cooling system. A 30kW solid rotor line-start PMSM with new structure was developed and analyzed in [6]. The study was focused on thermal field of the motor and influences of loads and stray loss on rotor temperature. This paper considers the thermal analysis on a radial flux permanent magnet generator using finite element T