Cost-Effective Current Reconstruction Method Using Two Sensors and a Single Shunt Resistor for MIDP PMSM Systems

초록

This paper proposes a current reconstruction method using a single shunt resistor to reduce the number of phase current sensors in a mono inverter dual parallel (MIDP) permanent magnet synchronous motors (PMSMs) drive system. Conventional MIDP PMSM drive system requires four phase current sensors, which account for a considerable portion of the overall system cost. Since the MIDP structure is typically adopted in cost-sensitive applications, reducing the number of sensors is particularly important. The proposed method achieves this by reconstructing the phase currents using the dc-link shunt together with two phase current sensors. In this configuration, the dc-link current represents the sum of the phase currents of both PMSMs, making it difficult to distinguish the individual currents of the two motors. To overcome this challenge, this paper proposes an algorithm that employs two phase current sensors placed in different phases, enabling accurate reconstruction of the three-phase currents for both motors. A compensation technique is incorporated to enable current reconstruction in all immeasurable regions, achieving reconstruction errors of approximately 3.07% and 2.08%. By reducing the number of sensors, the proposed method enhances the cost-efficiency and compactness of the MIDP PMSM drive system. The effectiveness and reliability of the proposed method are verified through both PSIM simulation and hardware-in-the-loop (HIL) experimental results.

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