Research on the adaptability of dynamic pitch control strategies on H-type VAWT close-range arrays by simulation study

Arranging VAWTs in close distance to form an array has been shown to be superior compared with a VAWT working alone. Existing studies on VAWT arrays mainly focused on the layout parameters of the VAWTs, while little attention is paid to the real-time control of individual rotor in VAWT arrays. This study preliminary explored the dynamic pitch control strategies in double-VAWT arrangements. Due to the interaction of adjacent turbines, the pitch control curve for VAWT in arrays should change with the inflow condition in different positions. Pitch control enables the downstream rotor deviating from the wake (ψ > 15°) to fully utilize the flow acceleration adjacent to the upstream VAWT. And the upstream rotor with pitch control also can improve the efficiency of its downstream rotor in the wake area. Results show that the overall power output of the arrangements can increase by more than 20% through suitable control strategies compared with zero-pitch VAWT array. The reduction of the rotor's blockage effect and the acceleration of the wake resulted from pitch control are the main reasons for the variations and improvement of the flow and the efficiency of the VAWTs in the arrangements. •Dynamic pitch method is separately applied to each VAWT in several staggered double-rotor arrangements.•The flow mechanism in the arrays caused by pitch control is analyzed and presented.•The recommended pitch control strategies and curves of VAWTs in different arrangements are given.•The average power coefficient of double VAWTs increased by 20% at most through optimization at the optimal TSR.