In this paper, the issues of ensuring the statically stable operation of a two-motor electric drive are considered, a fundamentally new system of coordinated rotation of asynchronous motors based on an electromagnetic working shaft (EMWSh) has been developed. A distinctive feature of EMWSh is the connection of the rotor windings of two or more motors to the power windings of an induction rheostat (IR) and capacitors. The issues of practical application of EMWSh and electroelectromagnetic working shaft EEMWSh with the inclusion of a capacitor in the rotor circuit of motor systems in multi-motor electric drives of crane movement mechanisms and long conveyor lines are studied.

Induction motors (IMs) consume most of the electricity used in industry, and the efficiency of their drives is classified through the IE and IES classes of IEC 60034-30-1 and IEC 61800-9-2. This PRISMA 2020 systematic review examines energy-efficient model predictive control (MPC) for IM drives using a three-axis taxonomy: efficiency objective (electrical loss, thermal/economic, degradation), solution paradigm (model-based, data-driven, learning-augmented), and uncertainty handling (nominal, observer-based, adaptive/robust). Of the 65 included studies, 43 concern induction-machine drives, but only three of these report an industrial, process, or marine load, and 20 of the 65 address traction or transport. The largest reported effects, 49–65% reductions in drive-cycle loss or energy and light-load efficiency gains of up to about 30 percentage points on a 0.75 kW machine, were obtained in simulation. Hardware-validated IM results mostly amount to about 0.7–4% in efficiency at fixed operating points and 8–18% in drive-cycle energy relative to other MPC variants. These figures are not directly comparable because loss boundaries, operating points, baselines, and validation methods differ. No included study combines a thermal/economic or degradation objective with a data-driven or learning paradigm and adaptive/robust uncertainty handling. Open problems and a research agenda on thermally adaptive economic MPC are outlined.

In loss-minimizing model predictive control of induction motor drives, the torque reference is often enforced by a quadratic penalty. Since every newton-meter costs loss, it leaves a steady torque error, and its weight has no physical basis. The error is shown to equal \( λ_M/(2q_M M^* ) \), where \( λ_M \) is the marginal loss per unit torque of the loss-optimal steady state, and a penalty on the absolute torque error removes it once its weight, in W/(N·m), exceeds the largest \( λ_M \)below the reference. The closed form of \( λ_M \) is derived from a temperature-dependent machine and inverter loss model. For a 7.5 kW drive at 36 simulated operating points, the closed-loop threshold equaled the marginal loss at fixed flux, which coincides with \( λ_M \) except on the voltage-limit boundary (up to 15% lower). The nominal quadratic weight left errors of 0.46–3.88%; with exact measurements the absolute-value penalty kept them below 10^-4%, also on pump and conveyor cycles, while the loss per unit of work changed by at most 0.6%. Without flux reservation it lowers and delays the torque during a current-limited flux rebuild, unlike a combined absolute-value and quadratic term. Field-orientation mismatch, measurement noise and dead time cause errors that the penalty does not remove.

In this paper, the issues of ensuring the statically stable operation of a two-motor electric drive are considered, EMWSh, has been developed. A distinctive feature of EMWSh is the connection of the rotor windings of two or more motors to the power windings of an induction rheostat (IR), some issues of the practical application of EMWSh systems in multi-motor electric drives for movement mechanisms of cranes and long conveyor lines.