Research On The Control Method Of Switched Reluctance Motor Based On Passivity Based Control

The switch reluctance motor drive system has been considered as a possible alternative to the conventional drives in several variable speed drive applications because of its advantages. Rugged motor structure and absence of magnets,rotor conductors and brushes along with the fault tolerant operation of the inverter, enable a very wide speed range. Recent literature shows that SRM derives are suitable for electric vehicles, electric traction applications, automotive applications, aircraft starter/generator systems, mining drives, washing machines, door actuators and etc.Because of saturation effect and variation of magnetic reluctance, all of significant characteristics of the SR motors such as flux linkage, inductance, back EMF and phase torque are highly nonlinear functions of both rotor position and phase current. Therefore, in spite of the simple mechanical construction, they need complex algorithms for commutation and control. In this paper, the control of switched reluctance motors is approached from a passivity-based control perspective. This controller is designed as follows.At first, a SRM nonlinear modeling is presented after investigating various modeling techniques for the purpose of controller design and simulation. The next step is to review the passivity theory and its suitability for control of SRM. Then controller design is separated into the inner loop and the outer loop. In the outer loop a single-neutron adaptive PID speed controller is designed to determine the appropriate torque command and then compared to a PID controller, finally to achieve high performance torque control. In the inner loop, passivity-based control(PBC) is employed to design a nonlinear feedback current controller by using energy shaping techniques to produce the proper switching function. Such a nonlinear controller is different from the others because of its energy-based approach. Finally, the Control algorithm is simulated through SIMULINK and simulation results confirm that the desired speed reference command is perfectly tracked and torque ripple reduced.The proposed controller solves the torque/speed tracking problem by exploiting the passivity properties of the machine. The methodology design considers the feedback decomposition of the motor model into one electrical and one mechanical passive systems and is divided into the following three steps: control of the electrical subsystem to achieve current tracking, definition of the desired current behavior to assure torque tracking, and design of a speed control loop. The main characteristics of the presented result are: it belongs to the class of control schemes that take into account the saturation effects present in stator windings and, regarding torque generation, it considers the use of torque share function for the purpose of torque ripple reduction. The contribution of the paper is threefold: the controller design is developed using energy-dissipation ideas, the mathematical formalization of the current engineering practice of controlling this kind of machines with a cascade approach, and an extension to previously reported passivity-based controllers for electric machines.