EXPANSION OF THE REALIZED RANGE OF MECHANICAL COORDINATES OF ELECTRIC DRIVES BASED ON SYNCHRONOUS MOTORS EXCITED BY PERMANENT MAGNETS

Relevance Modern traction electric drives based on permanent magnet synchronous motors (PMSM) require a wide range of torques and speeds. However, the natural characteristic of the PMSM does not correspond to the parabolic shape typical of traction systems, where a high torque is required at low speeds and its reduction at high speeds. Traditional control with maintaining zero current along the transverse axis (id = 0) ensures high energy efficiency, but limits the maximum speed, which narrows the operating range of the drive. Aim of research Development and analysis of PMSM vector control methods that allow expanding the speed range without significant deterioration in energy performance. Particular attention is paid to assessing the effect of demagnetization current (id < 0) on drive losses and selecting optimal control laws. Research methods The paper uses mathematical modeling based on the equations of the PMSM with implicitly expressed poles, where the currents along the d and q axes are expressed through the parameters of voltage, resistance, and angle θ between the voltage and EMF vectors. A comparative analysis of two control modes is performed, in particular, the classic (id = 0), which maximizes efficiency but limits speed, and the maximum torque mode, which expands the speed range by regulating the current iq and angle θ. The mechanical and energy characteristics are also calculated in relative units to assess the impact of engine parameters on performance and efficiency. Results It is shown that the proposed control method not only expands the speed range, but also maintains high energy performance of the drive. The maximum torque mode allows to significantly expand the speed range, but leads to an increase in losses at low values of the relative winding inductance ξ. It is established that at ξ → ∞ (low active resistance) the efficiency tends to 100 %, and the current id becomes constant, which minimizes additional losses. Based on the analysis of mechanical and energy characteristics, recommendations are proposed for selecting optimal control parameters that provide a balance between the control range and energy efficiency. The results of the work can be used in the design of traction electric drives for electric vehicles, rail transport and industrial mechanisms, where a combination of high starting torque and a wide speed range is required, as well as systems where both high torque and a wide speed range are critical. Thus, the article contributes to the development of vector control methods for PMSM, offering an effective solution for expanding the operating range of motors without deteriorating their energy characteristics.