Simplified Optimum Control Method for Monoinverter Dual Parallel PMSM Drive

This paper proposes a simplified optimum control strategy for a monoinverter dual parallel (MIDP) permanent magnet synchronous motor (PMSM). With reference to the parallel PMSM unified model, two different auxiliary conditions are investigated. The first minimizes the supplied inverter current, and the second maximizes the motor's efficiency. Their formal expressions are derived by the introduction of three new normalized variables, linked to the load conditions. Thus, the optimum tracking considerations are general, and the parameters are independent. Simplified closed analytical forms are found for the optimum tracking, independently under steady-state and transient conditions. The selection of the best solution is then found via a parameter independent look-up table, and imposed through a closed-loop control diagram. The proposed control is compared to the present state of the art via experiments on a 1400-W MIDP PMSM test bench, showing an equivalent performance, with a lower computational burden.