Energy efficient optimization for multi-motor system with novel inverter topology

Electric motors consume a large amount of energy in architectural buildings and industrial applications. Implementing high-efficiency motors and inverter driving systems can improve industrial energy efficiency and enhance societal sustainable development. This study proposes an efficiency-optimization control scheme for multi-motor drive applications based on a novel inverter topology. The multi-motor system operating in parallel is supplied from a new leg-sharing voltage source inverter (VSI) topology that arranges a common leg between the adjacent motors in turn and aims to reduce inverter loss and hardware cost. The specific model predictive control scheme combined with cycle division is designed for driving multi-motor independently and realizing switching state coordination of common legs concurrently. Compared to the traditional schemes, the deadbeat principle and multi-vector combination are adopted to improve output capacity within the affordable computational burden. In addition, a position controller using a cross-coupling structure is presented to fast suppress overcurrent in the sharing leg, thus decreasing inverter loss and extending the device lifetime, regardless of the given speed conditions. Finally, a three-motor platform is established to test the steady-state and transient performance of the proposed strategy and the comparative solutions. The test results indicate that the proposed drive scheme based on the leg-sharing VSI offers an overall efficiency enhancement and maintains excellent control properties simultaneously.