Current Error Space Vector Based Hysteresis Controller for VSI Fed PMSM Drive

The current error space vector based hysteresis controller with nearly constant switching frequency for voltage source inverter (VSI) fed permanent magnet synchronous machines drive is proposed in this article. A new method for online computation of voltage error vector is presented, from which the boundaries for hysteresis current controller is computed to maintain nearly constant switching frequency. Experimental results are given for the validation of the proposed method. With the proposed controller, the Fast Fourier transformer profile of the output voltage generated by the VSI is similar to that of a space vector modulated VSI, by maintaining nearly constant switching frequency. Explanations for variation in switching frequency are presented from a delay perspective of digital controllers. The contribution of machine parameter variations to alterations in the desired switching frequency is also investigated.