Optimisation Technique for DC-Excited Vernier Reluctance Synchronous Condensers

The use of distributed renewable energy led to a renewed interest in synchronous condensers. To solve the disadvantages of conventional wound rotor synchronous condensers, the DC-excited vernier reluctance synchronous condenser was recently proposed. This paper presents a developed optimisation technique to optimise this machine technology as a synchronous condenser. The primary optimisation objective is to maximise the reactive power per losses for a fixed machine volume. An optimum synchronous condenser selection criterion from the optimisation Pareto front is proposed, based on the relationship between the required reactive power and an efficiency indicator of reactive power per losses. The paper presents a case study in which the optimisation technique and selection criterion are applied to an existing machine. The optimisation results prove that the proposed optimisation technique can be used to design the DC-excited vernier reluctance machine as synchronous condenser with a balanced capability of absorbing and supplying reactive power.