This paper presents the experimental investigation of DSP based 4Ф Switched Reluctance Motor (SRM) Drive. SRM is a doubly-salient, singlyexcited machine and having very simple construction, has a low inertia and allows an extremely high-speed operation. The control system of SRM is highly complex due to non linear nature. In such a system for implementing control algorithm needs high speed processor. In this work TMS320F28335 DSP processor is used to implement the inner loop PI current controller and outer loop PI speed controller. The TMS320F28335 is highly integrated, high performance solution for challenging control applications. Email: natarajmekala@gmail.com
INTRODUCTIONThe SRM have a simplest construction of all electrical machines and only the stator has windings. The rotor contains no permanent magnets. It consists of steel laminations stacked onto a shaft. The rotor is aligned whenever the diametrically opposite stator poles are excited. The magnetic circuit rotating part prefers to come to the minimum reluctance position at the instance of excitation and two rotor poles are aligned to the two stator poles, the other set of rotor poles is out of alignment with respect to a different set of stator poles [1]. Then, this set of stator poles is excited to bring the rotor poles into alignment. It is because of this simple mechanical construction that SRMs carry the low manufacturing cost, and also it provides high reliability, wide-speed range at constant power, fast dynamic response, ruggedness and fault-tolerance, 80% efficiency depending on the application and high starting torque [2]-[3]. This in turn has motivated a large amount of research on SRMs in the last decade. The SRM operation is extremely safe and the motor is used in industrial and domestic applications like robotics, aerospace, washing machine and also vacuum cleaner. In [11], a speed control of 4Ф 8/6 SRM using DSP TMS320F2407A was proposed. The converter is fed through a DC split converter was discussed in [7]. The speed is regulated through a PWM controller in which, the average phase voltage during the conduction period is controlled by varying the duty ratio of the switches. The implementation of speed controller for switched reluctance motor drive using fuzzy logic controller was proposed in [14]. This speed controller show that the FLC is more robust and, hence it is a suitable replacement of the conventional controllers for the high-performance SRM drive applications. In [9], A New Random Switching Technique using DSP TMS320F2812 was presented. This technique brings acoustic noise decrease by combining the varying turn-on, turn-off angle and RPWM. The experimental results show that the harmonic intensity of output voltage is better than other conventional methods.
