GENERATORS AND C ONTROLLERS FOR M ICRO POWER BASED DISTRIBUTED POWER SYSTEMS

Abstract

Micro turbine based generator systems are becoming popular for
providing electric power and heat in a cogeneration environment. The
reason for this is the fact that the high-speed turbo-generator sets are
very compact in size and are competitive in the cogeneration environ-
ment. The electric generator is directly coupled to the high-speed turbine
and must be capable of operating at the high speed. The typical micro
and mini turbine speeds are in the range of 30,000 rpm to 120,000 rpm.
The higher the power, lower is the speed. Thus a 40-kW micro turbine-
generator may operate at 120,000 rpm, while a 500-kW mini-turbine may
operate at 30,000 rpm.
This article addresses a 200 kW, 60,000 rpm generator and control-
ler suitable for direct coupling to a turbine. Many of the micropower
units available in the market use permanent magnet generators. In the
design presented here, induction generator technology is applied. It is
believed that induction generators offer benefits such as lower cost,
higher cycle efficiency, and safety of operation