Abstract—The present paper proposes the energy storage system on the batteries with PWM method with the objective regulating the SEIG output voltage during load variation. This method uses the configuration uncontrolled rectifier with a PWM chopper-controlled battery charging. In this study, the SEIG is of 1.5 kW, 380-420 V, 3.5 A, Wye connected. The proposed system shows that the terminal voltage of SEIG can be regulated at a constant value of 406 volts for resistive load variations of 720 watts to 1386 watts. Beside, the frequency of generator can also be maintain at a constant value of 50 Hz. While keeping the generator output voltage constant the power flow from generator to the battery varies from 0 to 444.8 watts. Keywords—Battery, Pulse Charging, PWM DC Chopper, Self- Excited Induction Generator. I. INTRODUCTION He research on use of Self Excited Induction Generator (SEIG) and its peformance improvement has been carried out extensively in the last decade [1]. The successfull of SEIG performance has been supported to some extent by advances of power electronics, especially in the field of static power converter. Compare SEIG to synchronous generators (conventional generators) has several advantages, such as: cheap, easily available, less maintenance, robust construction, simple protection and operation. Owing to advantages and improved performance, SEIG has been being in small scale electricity generation driven by renewable energy sources, such as micro-hydro and wind power. Micro Hydro Power Plant (MHPP) is a electric power generation driven by micro hydro power with capacity less than 100 kW. Currently, the use of induction generators in the MHPP system grows rapidly. Generally, the MHPP operates turbine power input (mechanical power) relatively constant, with generator power capacity in accordance with the peak load or maximum power [2,3,4]. Since, the MHPP load always fluctuates, so that the output voltage and frequency will also fluctuate following the load variations. Refdinal Nazir is with the Electrical Engineering Departement, Andalas University, Padang 25163, Indonesia (phone: 062-751-7891208; e-mail: refdinalnazir@ yahoo.co.id). Andi Pawawoi is with the Electrical Engineering Departement, Andalas University, Padang 25163, Indonesia (phone: 062-751-72566; e-mail: andipawowo@ft.unand.ac.id). Farah Rahmadhani is with the Electrical Engineering Departement, Andalas University, Padang 25163, Indonesia (phone: 062-751-72566; e- mail: hamasah_0k@yahoo.com). A Widely used method to maintain the generator voltage constant during load variation is the method of electronic load control (ELC). In case of SEIG this method is also called the method Induction Generator Control (IGC). In this method, the balance between input and output power is maintained with the installation of ballasts that serves as a dump load. If there is variation of the load then the ELC/IGC would regulate a ballast power so that the power of generator can be maintained constant. Some technique to regulate the output voltage of induction generator using ELC/IGC has been presented elsewhere [2,3]. The technique include binary-weighted switched resistors, phase-controlled thyristor-based load controllers, controlled rectifiers feeding dump loads, and uncontrolled rectifier with a chopper-controlled dump load. The last technique has several advantages, in that the scheme is simple, cheap and reliable, the operation does not require reactive power, and only need a ballast. However, the use of ballasts will be dissipated heat represent energy loss. In case where, the power demand (load) is less than the power output generator, there will be excess energy production of the SEIG. This excess energy may be storied in batteries.Simulation and analysis to utilize excess energy of the SEIG with a method of energy storage in batteries has been conducted by several researchers previously [5-7]. The performance of SEIG equiped Static VAR Compensator (STATCOM) and a battery has been analyzed using the simulation program SIMULINK/MATLAB [5]. VF controller model for SEIG using Voltage Source Converter (VSC) and battery have been simulated using MATLAB with Simulink and SimPower System (SPS) toolboxes [6]. The development ELC/IGC with the batteries to increase the ability of SEIG on household electrical energy supply with energy storage method on the battery has been analyzed [7]. In the present paper, the energy storage system on the batteries with PWM method used to regulate the SEIG output voltage during load variation is proposed and discussed. The proposed system is analyzed, designed and tested in the laboratory. The results for testing of system performance are presented and evaluated. Refdinal Nazir, Andi Pawawoi & Farah Rahmadhani The Energy Storage System on the Batteries with PWM Method to Regulate the Output Voltage of SEIG T World Academy of Science, Engineering and Technology 78 2011 81