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Modular motor drives can be considered as multi‐agent systems, in which the agents can work together to reach a common goal. One agent in such a modular motor drive consists of only a subset of the machine phases and power electronic converter modules, and is equipped with a dedicated controller. When the dc‐links of the different agents are connected in series to a single voltage source, giving rise to a so‐called stacked polyphase bridges converter, the power electronic converter components can have low voltage ratings. However, a voltage balancing controller must ensure that the total dc‐link voltage is distributed evenly among the agents when working in motoring mode. The goal of this research is to propose a multi‐agent voltage balancing algorithm based on dynamic average consensus, which depends solely on local computations, local measurements, and neighbour‐to‐neighbour communication. The scalability and reliability of the modular hardware are hence extended towards the control. Simulations and experimental results on a 4 kW modular axial‐flux PMSM demonstrate the feasibility of the concept. [ABSTRACT FROM AUTHOR]

A stacked polyphase bridge converter consists of multiple standard, three‐phase two‐level voltage source inverters connected in series to the same dc voltage source. The authors present a decentralised and dynamic dc‐bus reconfiguration strategy for this type of converter. The innovation of the proposed strategy lies in its ability to isolate or reactivate one of the inverters in the series connection online, even in motoring mode, enabling increased fault tolerance and an extended speed range. Both the required hardware alterations and the multi‐agent control strategy are addressed. Its major benefits compared to the state‐of‐the‐art are that only two additional active, unidirectional semiconductor switches are required per inverter, and that the control is based on local computations, local measurements and neighbour‐to‐neighbour communication only. Hence, the scalability and reliability of the hardware are extended towards the control. Simulations and experimental results on a 4 kW modular axial‐flux PMSM prove the feasibility of the concept, and validate that the dc‐bus can be reconfigured in 100 ms, without torque interruption. [ABSTRACT FROM AUTHOR]