Radial Flux Permanent Magnet Generator Research Articles

Design Study of Dual Generated Radial Flux Permanent Magnet Generator for Pico Hydro Generator

The RFPM(Radial Flux Permanent Magnet) generator has numerous advantages such as high output voltage and output power, high efficiency, manufacture easy but the slotted RFPM generator configuration produces the cogging torque. The cogging torque would be the source of acoustic noise and vibration. This paper presents the electromagnetic structure design analysis and the cogging torque reduction design of RFPM generator. It is composed of the inner stator and the outer stator and internal rotor. We called it as DG-RFPMG(Dual Generator-Radial Flux Permanent Magnet Generator). Firstly, the design of the pole-arc ratio of rotor magnets to reduce cogging torque is studied. Secondly, the design of the stator displacement of the outer stator and the inner stator to reduce the cogging torque is studied. Finally, the combined design optimization considering both the pole- arc ratio and the stator displacement to reduce the cogging torque is studied. The design of DG-RFPMG was calculated by 2D FEM(Finite Element Method).

Magnetic Simulation and Analysis of Radial Flux Permanent Magnet Generator using Finite Element Method

This paper discusses magnetic simulation and analysis of radial flux permanent magnet generator (PMG) using finite element method (FEM) by utilizing open source software FEMM 4.2. The specification of generator is 25 V, 28 A, 3 phase, 300 rpm. The analyzed magnetic flux was in the air gap, stator teeth and slots to find out the distribusian pattern and its fluctuation. The simulations were conducted in no-load and nominal load (28 A) conditions. Furthermore the maximum flux density of simulation (B g(sim) ) was used to calculate phase voltage E ph to find out the magnitude of generated electromotive force (EMF). The calculation results were presented as voltage vs. rotation graph in no-load condition and voltage vs. current graph in nominal load condition. Both graphs were validated with E ph of experiment result (E ph(exp) ) and E ph that the value of B g obtained from analytical calculation (E ph(calc) ). The final results showed that in no-load condition, E ph graph with B g(sim) (E ph(sim) ) was close to E ph(exp) and E ph(calc). The error rate with respect to the experiment was 6,9%. In nominal load condition, E ph(sim) graph almost coincides with E ph(calc.) graph, with the voltage drop of both was 0,441 V. Both graphs however were far different from E ph(exp) graph, which has 9 V of voltage drop. The overall results demonstrated that magnetic distribution pattern presented by FEM was very helpful to avoid magnetic flux accumulation in a particular segment. Besides B g(sim) facilitated to predict the value of E ph .

Thermal Analysis on Radial Flux Permanent Magnet Generator (PMG) using Finite Element Method

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 39.1oC and 72.5oC respectively while the experimental maximum temperature of the winding is 62oC.

Design optimization and site matching of direct-drive permanent magnet wind power generator systems

This paper investigates the possible site matching of the direct-drive wind turbine concepts based on the electromagnetic design optimization of permanent magnet (PM) generator systems. Firstly, the analytical models of a three-phase radial-flux PM generator with a back-to-back power converter are presented. The optimum design models of direct-drive PM wind generation system are developed with an improved genetic algorithm, and a 500-kW direct-drive PM generator for the minimal generator active material cost is compared to demonstrate the effectiveness of the design optimization. Forty-five PM generator systems, the combinations of five rated rotor speeds in the range of 10–30 rpm and nine power ratings from 100 kW to 10 MW, are optimally designed, respectively. The optimum results are compared graphically in terms of the generator design indexes. Next, according to the design principle of the maximum wind energy capture, the rotor diameter and the rated wind speed of a direct-drive wind turbine with the optimum PM generator are determined. The annual energy output (AEO) is also presented using the Weibull density function. Finally, the maximum AEO per cost (AEOPC) of the optimized wind generator systems is evaluated at eight potential sites with annual mean wind speeds in the range of 3–10 m/s, respectively. These results have shown the suitable designs for the optimum site matching of the investigated PM generator systems.