Thermal effectiveness of explosion-proof hoist inverter based on improved QD-MPCC

Abstract

The working conditions of the explosion-proof hoist inverter are particular. During heavy load and frequent lifting, power devices of the inverter will generate considerable power loss, which often leads to overheating or even damage to power devices and reduces the thermal stability of the whole system. This study proposes a quasi-deadbeat model predictive current control (QD-MPCC) strategy based on the neutral point clamped (NPC) three-level inverter. First, the QD-MPCC quasi-beat controller of the induction motor is designed, the digital delay compensation strategy is developed, and a closed-loop flux observer is adopted to improve the flux observation accuracy. Second, the traditional QD-MPCC strategy is improved. The loss model of the NPC three-level inverter applied to the explosion-proof hoist is established. Then the loss result calculated according to the predicted current is taken as the new control target, and the loss is dynamically optimized according to the operating curve. Finally, the robustness of the improved QD-MPCC strategy and its effectiveness in online power-loss management to improve the thermal stability of the system are verified by simulation and experiment.