Sensorless Control System Research And Design Of SRM Over Entire Speed Range

Switched reluctance motor (SRM) has many advantages, such as simple structure,flexible control, fault-tolerant and so on. While the switched reluctance motor drivesystem (SRD) is a blend of the two major advantages of AC and DC control system.The SRD has been widely used in mining, aerospace, electric vehicle drive, machineequipment and many other industrial fields. However, the position sensor used todetect the rotor position information brought many adverse effects such as reducesystem reliability, installation inconvenience, cost and complexity increases to SRD.The position sensor becomes a bottleneck of SRM to promote. So the technicalresearch of sensorless control of SRM has extremely important practical significance.In order to achieve sensorless control of SRM at startup or high and low speed driveoperating two operating states, this paper studies a sensorless control strategy basedon complex plane inductance model.Firstly, this paper summarizes the rotor position detection technology at homeand abroad of SRM at startup and drive operating two operating states. And this paperintroduces the operating principle, basic mathematical equations and mathematicalmodels of SRM, discusses the common control strategies and operationalcharacteristics.Secondly, this paper obtains the flux characteristic curve of18.5kW prototype bytwo method of finite element analysis and half-cycle excitation. The principles andprocedures of the flux characteristic obtained are given in the paper. Magnetic fluxdensity and magnetic field intensity of18.5kW SRM are analyzed by3D finiteelement simulation of JMAG software. In addition, the paper analyzes the results offlux characteristic obtained of18.5kW prototype by two methods above-mentioned.For the problem that rotor position detection of SRM at startup, low and highspeed drive operating two operating states, the paper proposes a sensorless controlstrategy over entire speed range based on complex plane inductance model. Thearticles start from the functional relationship between complex plane inductancemodel and angle to describe the rotor angle estimation principle. And the method thatthree coefficients of complex plane inductance model obtained by flux characteristicof SRM is given. The paper further analyzes the estimation error when rotor positionangle at different sectors. On this basis, the method to compute three phaseinductances of SRM at startup, low-speed drive operating and reference phase inductance of high-speed operating states is elaborated, and the selection rule ofreference phase is also given. The influence of the inductance saturation effect onrotor angle estimation at low-speed drive operating states is analyzed. And the papertakes compensatory measure of three coefficients to eliminate the impact. Thefeasibility of the rotor position detection method at startup and low-high speed drivedifferent operating states is verified by MATLAB simulation. Moreover, thesensorless control strategy over entire speed range from startup to drive operating isgiven in the paper, and the feasibility of sensorless algorithm switching strategybetween high and low speed drive operating states is verified by simulation.Finally, this paper introduces hardware and software design of sensorless controlexperiment platform. And the sensorless control algorithm over entire speed rangeproposed is verified by experiments. The experimental results show that the sensorlesscontrol algorithm proposed is effective over entire speed range, and this method canalso implement startup of sensorless control at those with initial speed conditions.