Dual Parallel-PMSM System Using Single PMSM Control Hardware: A PLL-Integrated UIO Approach

A permanent magnet synchronous motor (PMSM) control hardware has integrated two phase-current sensors and a rotor position sensor to realize the control of the motor. Connecting an additional PMSM in parallel without modifying the control hardware would further reduce the cost of building up a multimotor system. However, in this new configuration, not all the necessary information is available directly from the existing sensors, resulting in potential risks in controlling the system properly. In this article, a new unknown input observer (UIO) is developed via interval observer joint phase-lock-loop. The proposed UIO can asymptotically not only estimate the phase current of each motor but also reconstruct the rotor position of the additional motor. Then, a delicately designed controller together with the proposed UIO realizes the speed control of the system. Comprehensive experiments including start-up, speed, and load torque variation verify that the proposed system can achieve the desired goal either in the steady or transient operation state. Moreover, the controller's robustness to variations in stator resistance, inductance, and flux are verified both by simulation and experiment. In this way, without equipping any additional sensors, building a dual parallel PMSM based on conventional single PMSM control hardware is entirely feasible in practice.

Automated summary

This article proposes a method to build a dual parallel PMSM based on traditional PMSM control hardware without additional sensors, and verifies the performance of the system and the robustness of the controller through experiments.