Constant speed drive

A constant speed drive (CSD) is a system that takes rotational power from an engine and ensures that a generator connected to it maintains a constant speed, regardless of the engine speed. This is achieved through a hydro-mechanical CSD connected to the engine via a gearbox, which regulates the output frequency of a three-stage regulated synchronous generator. The CSD is commonly used in aircraft to maintain a consistent power supply.From: Electrical Machines [2016], A hybrid reference current extraction technique with multi-functional capability for shunt active filter in all-electric aircraft [2020]

Synchronous Machines

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Published in Jacek F. Gieras, Electrical Machines, 2016

Jacek F. Gieras

Also, generators are turned by a differential assembly and hydraulic pumps to obtain constant speed. The purpose of the constant speed drive (CSD) is to take rotational power from the engine and, no matter the engine speed, turn the generator at a constant speed. The CSD converts variable engine speed into constant speed to run an AC generator. This is necessary because the generator output must be constant frequency, e.g., 400 Hz.

A hybrid reference current extraction technique with multi-functional capability for shunt active filter in all-electric aircraft

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Published in International Journal of Ambient Energy, 2020

Kumar Reddy Cheepati, Nageswara Rao Maddala, Surya Kalavathi Munagala

The Constant Speed Drive (CSD) generating system found in many aircraft consists of a three-stage regulated synchronous generator where the output frequency is maintained constant by means of a hydro-mechanical CSD connected to the engine via a gearbox. A reduction in the weight of the system is achieved by the combination of the drive and generator integrated to form a single unit that leads to Integrated Drive Generator (IDG) (Eid et al. 2010). The developments in power electronics and microprocessor technology have led to the dc-link VSCF generating system, becoming a viable alternative to the CSD and IDG systems (Rosero et al. 2007). The VSCF electrical system, shown in Figure 1, is more flexible than the CSD/IDG systems since its components are distributed throughout the aircraft, in contrast to the CSD/IDG mechanical system in which they must inevitably be located close to the engine (Cao et al. 2012; Sharma, Capoor, and Chattopadhyay 2015).

Constant speed drive

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Synchronous Machines

A hybrid reference current extraction technique with multi-functional capability for shunt active filter in all-electric aircraft