2014 17th International Conference on Electrical Machines and Systems (ICEMS),Oct. 22-25, 2014, Hangzhou, China 978-1-4799-5162-8/14/$31.00 ©2014 IEEE Abstract — Utilization of renewable energy has increased spectacularly in recent years, with the high energy demand and fast decaying of fossil fuels. Renewable energy, especially solar energy has been the power choice for many applications such as solar powered induction motor drive. For that reason, this paper aims to propose an open loop speed control method for achieving high performance over a wide range of operating speeds. The proposed induction motor drives are supplied by a solar power system which consists of two-stages of power conversion; DC-DC boost converter with maximum power point tracker (MPPT) for the first stage and DC-AC three-leg voltage source inverter supplying a two-phase induction motor load for the second stage. A modulation strategy is developed to supply unbalanced two- phase output voltage based on the carrier-based space vector PWM (SVPWM) with open-loop V/F control. The performance characteristics of the induction motor with the proposed method are determined by two modulation strategies namely balanced and unbalanced SVPWM. The validity of the proposed method is verified by simulation results. I. INTRODUCTION Single-phase induction motor (SPIM) have been widely used in industrial and domestic applications. SPIM have two stator windings, a main winding and an auxiliary winding. A capacitor is connected in series with the auxiliary winding to shift the phase of auxiliary winding current which is related to the main winding current by 90 degrees. Thus, the SPIM becomes an asymmetrical parameter type two-phase induction motor (TPIM) if the capacitor is removed and supplied to the both windings with the two voltage sources and 90 degrees departure [1], [2]. The commonly employed speed control technique is the stator voltage control, where the AC supply voltage is varied to obtain wide speed operation. However, this method has experienced several problems. Therefore, it is essential that, to achieve better performance in lower speed ranges, the supply frequency should be changed in accordance with its voltage value to maintain constant level of magnetization [3]. An asymmetrical parameter type TPIM is probably adapted from an existing single-phase split capacitor induction motor (SPCIM) by removing a capacitor out of the auxiliary winding. Many research efforts have been made to improve the performance of drive not only by a control method but also by a pulsewidth modulation strategy [4]-[6]. This paper presents two types of space vector (SVPWM) strategy for a three-leg voltage source inverter (VSI) fed asymmetrical parameter type TPIM with open-loop V/F control, a balanced phase voltage SVPWM (B-SVPWM) and an unbalanced phase voltage SVPWM (U-SVPWM) [7]. To improve the performance characteristics of the TPIM when operated with variable frequency supplies, it is required to control both main winding voltage and auxiliary winding voltage independently. Normally, adjustable voltage with variable frequency supply can be obtained from inverter with constant DC input voltage which is provided by rectifier circuits. However, with the advent of renewable energy resources, photovoltaic (PV) array is often considered the best power source for DC supplies voltage [8]. It is necessary to obtain higher voltage for three- leg VSI driving TPIM with rated flux. Therefore, a boost converter is included with MPPT to achieve sufficient DC link voltage and increased of the system efficiency. Several papers in the world was proposed different MPPT control algorithms in the past years [9]-[11]. The simplest method is perturbation and observation (P&O) method, it is often used in many PV systems. Therefore, this scheme is used in this work which is not focused. In this paper, modeling and simulation of a PV powered three-leg VSI fed asymmetrical parameter type TPIM drive system using the open-loop V/F control have been performed with motor load using MATLAB/Simulink. In the first section the principle of induction motor driven by PV system are presented. The working of the proposed speed control technique and its control strategy is explained in the second section. In the third section the drive characteristics with the proposed method are simulated for different operating conditions are described. The simulation results obtained are presented and discussed in the last section. II. INDUCTION MOTOR DRIVEN BY PV SYSTEM The conventional speed control method for variable speed operation of SPIM driven by PV system under variable frequency supplies is shown in Fig. 1. With conventional speed control method, the SPIM is operated at constant voltage variable frequency supply fed by VSI. However, SPIM have experienced several problems such as low efficiency, low power factor and torque pulsations. The problems are caused from the capacitor in motor is adversely affected by changes in the frequency supplies by the VSI. To overcome the above mentioned effects, the method proposed have been developed PV Powered Three-Leg VSI Fed Asymmetrical Parameter Type Two-Phase Induction Motor Ekkawid Hayakwong, Vijit Kinnares Department of Electrical Engineering, Faculty of Engineering King Mongkut’s Institute of Technology Ladkrabang, Thailand E-mail: ekkawid@yahoo.com 3220 Authorized licensed use limited to: Rajamangala Univ of Technology Isan provided by UniNet. 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