International Review of Electrical Engineering (I.R.E.E.), Vol. xx, n. x Manuscript received March 2012, revised June 2012 Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved FPGA Based Optimized Discontinuous SVPWM Algorithm for Three Phase VSI in AC Drives Tole Sutikno 1 , Nik Rumzi Nik Idris 2 , Auzani Jidin 3 , Mohd Hatta Jopri 4 Abstract – The discontinuous space vector pulse width modulation (SVPWM) has well-known that can reduce switching losses. By simplifying the thermal management issues, the discontinuous SVPWM can potentially reduce the inverter size and cost. However, using the modulation due to different time interval equations for each sector can introduce glitches at the points when the sector is changed. The more main problem, it can increase unwanted harmonic content and current ripple. Consider the decrease in switching losses associated with discontinuous modulation allows the system to utilize a higher switching frequency, this paper present high frequency switching of optimized discontinuous SVPWM based on FPGA to overcome the problems above. The proposed SVPWM has been successfully implemented by using APEX20KE Altera FPGA to drive on a three phase inverter system with 1.5 kW induction machine as load. The results have proved that the method can reduce harmonic content and current ripple without glitches. Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved. Keywords: electric drives, FPGA applications, motor controls, power converters, space vector pulse width modulation (SVPWM) Nomenclature DSP digital signal processors FPGA field programmable gate array I a output of A-phase stator current IGBT insulated-gate bipolar transistor P L switching losses PWM pulse width modulation S a , S b , S c switching status a-b-c legs SPWM sinusoidal pulse width modulation SVPWM space vector pulse width modulation T switching period THD total harmonic distortion T J junction layer temperature V a , V b , V c voltages in abc-reference frame V ab output of phase-to-phase voltage V an output voltage line-to-neutral V dc DC voltage source V α , V β voltages in αβ-reference frame I. Introduction The key requirements of any modulation method are to provide higher power output and efficiency for a wide range of inverter output voltage control. The SVPWM method is an advanced PWM method at which it is possibly the best among all the PWM techniques for variable frequency drive applications, since SVPWM can provide a better fundamental output voltage, better harmonic performance and easier be implemented [1-11]. The SVPWM strategies have been the focus of many years of research attempt. In recent years, the SVPWM method gradually obtains widespread applications in the power electronics and the electrical drives due to its superior performance characteristics. The SVPWM is more suitable for digital implementation compared to the SPWM, whereby the obtainable DC voltage utilization ratio can be highly increased. As the result, a better voltage THD factor can be obtained [1, 5-6, 10-12]. The comparison of P L , T J junction IGBT, and weighted THD of the different modulation schemes are shown in Table I [13]. From the comparison, although the discontinuous SVPWM (or bus clamping SVPWM) gives a slightly higher of weighted THD compared with conventional SVPWM method, the result in lowest switching losses and lowest junction temperature of IGBT compared with the SPWM and conventional SVPWM. The switching loss of the discontinuous SVPWM is consistently lower than those of SPWM and SVPWM as there are fewer switching instants and that the dead-time effect is smaller since there is no switching during the DC clamped period. At higher line-side voltages for a given average switching frequency, the discontinuous SVPWM have lower THD in line currents than the continuous SVPWM methods [2, 14-17]. The discontinuous SVPWM also provides a linear range of modulation index 0-115.4% [18]. It is, therefore, can increase the power handling capability of the converter, or its need for cooling, and increasing the converter power density. It is suitable to minimize the weight and volume of power electronics systems, as in electric vehicle and aircraft applications. The discontinuous SVPWM initially developed by Depenbrock [19] in 1977. Currently, the discontinuous