Experimental nonlinear torque control of a permanent-magnet synchronous motor using saliency

Abstract

In this paper, a new nonlinear control strategy is proposed for a permanent-magnet salient-pole synchronous motor. This control strategy simultaneously achieves accurate torque control and copper losses minimization without recurring to an internal current loop nor to any feedforward compensation. It takes advantage of the rotor saliency by allowing the current (i d ) to have nonzero values. This, in turn, allows us to increase the power factor of the machine and to raise the maximum admissible torque. We apply input-output linearization techniques where the inputs are the stator voltages and the outputs are the torque and a judiciously chosen new output. This new output insures a well-defined relative degree and is linked to the copper losses in such a way that, when forced to zero, it leads to maximum machine efficiency. The performance of our nonlinear controller is demonstrated by a real-time implementation using a digital signal processor (DSP) chip on a permanent-magnet salient-pole synchronous motor with sinusoidal flux distribution. The results are compared to the ones obtained with a scheme which forces the i d current to zero.

A Self-Learning Solution for Torque Ripple Reduction for Nonsinusoidal Permanent-Magnet Motor Drives Based on Artificial Neural Networks

“…While working in the d-q reference frame of Park, the authors in [20], [21] determine the expressions of the d-q optimal currents; [21] optimizes only for one harmonic of rank 6. A direct expression of the a-b-c currents is given in [22], [23] by using an extension of Park's transformation. In [24], an adaptive process based on the Fourier series expansion is presented for a machine containing 4 pairs of poles and 24 stator slots.…”

Generic maximum power point tracking controller for small-scale wind turbines

“…If the permanent magnets are uniformly mounted on the rotor surface, then L d and L q may be assumed equal and the electromagnetic torque becomes [11]; . This loss increases at higher torques (as I G is higher) and this operation is associated with low rotational speed and low voltage for the same output power.…”

High dynamic performance of a BLDC motor with a front end converter using an FPGA based controller for electric vehicle application

“…This results in two phases conducting at a time and producing the torque. Therefore, for trapezoidal variation of induced back EMFs and with an assumption that phase inductances are constant, the equations governing the above described induction profile of the BLDC motor in abc reference frame [20] are given by Figure 3 shows a three phase front end converter for speed control of the BLDC motor drive system through electronic commutation. Each leg has two IGBT switches, accompanied by antiparallel flywheel diodes, which are complementary in their switching action.…”