Low-speed direct-driven sensorless control including zero-speed for switched reluctance motor based on dynamic inductance model

Accurate and reliable rotor position estimation is extremely required in low-speed direct-driven applications for switched reluctance motor/generator. Due to seriously nonlinearity of phase inductance, phase inductance changes obviously under saturation. On the basis of Fourier analysis, the relationship between dynamic inductance model coefficients and phase current is given. At zero-speed condition, excitation pulse method is proposed for estimate initial rotor position. Dynamic inductance model is proposed for low-speed operation. Sensorless control algorithm is achieved by DSP and FPGA chips. Experimental results indicate that motor start up without inversion at zero speed, sensorless operation error is less than 0.5 degree. The overall sensorless control scheme is easy to implement.