Controlling a permanent-magnet motor using PWM converter in flywheel energy storage systems

Flywheel energy storage systems are very useful in power-conditioning applications. One of the main concerns of the automobile industry is the search for more environmental friendly power systems. The implementation of flywheel batteries in the hybrid-electric or all-electric automotive vehicles is on the road ahead. Following this direction, a power DC-AC converter has been designed and built to govern an AC machine to be used in a flywheel battery system. Different load connections have been investigated. An output RLC filter has also been designed and built to minimize the harmonics due to the switching operations of the pulse width modulated (PWM) converter that drives the motor. Simulations were carried out using PSpice and compared with corresponding laboratory experiments. It is found that the harmonics were considerably reduced when a RLC output filter was included in the system. The simulation results were verified with the experimental results as they showed a good agreement.