International OPEN ACCESS Journal Of Modern Engineering Research (IJMER) | IJMER | ISSN: 2249–6645 | www.ijmer.com | Vol. 4 | Iss. 6| June. 2014 | 6| Design and Development of Gate Signal for 36 Volt 1000Hz Three Phase Inverter Devender Singh 1 , Dr. Syed Hasan Saeed 2 1 PG Student, Integral University Lucknow,India, SSO-I, DGAQA, HAL-Lucknow, India 2 HOD, Electronics And Communication Engineering, Integral University, Lucknow, India I. INTRODUCTION Aerospace industry is a complex field of engineering, where all the branches of science and technology have made their presence in general and specific in particular such as use of rectifier unit, rotary inverter, static inverter in power system of fighter aircraft.Though the use of Sinusoidal pulse width modulation inverter is very common in single and three phases of commercial inverters working on frequency 50 Hz/60Hz available in open market, but the article under question wherein the developed gating signal for 1000Hz,three phase for inverter of 36 volt is taken up in this paper. Other popular version of inverter in aircraft industry is 400Hz, 3 phase, 36 Volt; which is used in older version of fighter aircraft to provide power supply to gyros. In high speed aerospace vehicle such as missiles and aircraft with supersonic and hypersonic speed;inverter of 36volt, 3 phase, 1000 Hz can be used. The rigidity and degree of precession of gyro is directly depend on frequency of rotation of gyro mass. In modern aircraft, mechanical version of gyro is replaced by LRG (Laser Ring Gyro) or FOG (Fiber Optics Gyro) [3]. The 1000 Hz, 3 phase, 36 Volt supply can be used to operate gyro and synchro in modern aircraft and missiles. II. Literature Survey The authors have surveyed various papers published in journals and studied the features of invertors, type of SPWM method for generation and no evidence of work on 1000Hz, 3 phase, 36 Volt is found. However, for commercial power supply i.e 230 Volt, 50Hz, single phase and 400 volt, 3 phase 50 Hz;a lot of papers are found. The advantage of SPWM is clearly mentioned in [1]. Sinusoidal PWM results in lowest THD percentage as compared with other techniques like square wave PWM, trapezoidal PWM and modified sinusoidal PWM [2]. Therefore, SPWM method is chosen for design. III. SPWM The brief details of the SPWM are as follows: (a) In SPWM sinusoidal signal frequency is compared with triangular carrier frequency. (b) Sinusoidal signals {V 1 = A Sin ωt, V 2 =A Sin (ωt-120◦), V 3 = A sin (ωt+120◦)} are fed to be positive inputs of comparators and triangular signal (common to all three comparators) to the negative input of comparators. (c) The pulse corresponding to the point whenever the instantaneous amplitude of sine signal is more than triangular signal then a pulse is generated. The width of the pulse is function of sinusoidal angular position. (d) The pulse width varies with sinusoidal manner so that the average fundamental component frequency is the same as sinusoidal signal. (e) It is necessary to maintain carrier frequency (triangular wave) ofat least 15 times more than the frequency of sinusoidal signal (1000 Hz). In practice, carrier frequency greater than 21 times are preferred; because, it reduces sub harmonic contentin the output of inverter. (f) The rms value of line voltage; Vl = √3 Vs. In present case, it will be approx110 volt DC to be applied at MOSFET bridge to get 36 volts, phase to phase at inverter output. This is transformer-less design and output voltage can easily be changed by changing MOSFET bridge supply. Abstract: The sinusoidal PWM gating signals generation is most popular PWM method, which reduce harmonic reduction in output. SPWM can be generated by FPGA, micro controller and micro processor but this kind of device needs programming and coding hence avoided in using power system of aircraft. This paper present an experiment using SPWM method to generate 1000 Hz gating signals suitable for 36 Volt , 1000 Hz, 3 phase, three wire supply. Discrete components design approach is chosen to provide noise immunity at higher amplitude level of signal and a large flexibility to adjust and process various operating parameters of signals. The circuit is proved with commercial components however MIL version of components can be easily incorporated in design in later stage. Keywords: aircraft, comparator,gyro, sine wave, triangular wave.