초록 ▼

A stabilized control system and method for smoothly connecting and disconnecting an induction generator to the utility power grid is described. Thyristor switches are interposed between each phase of the mains and the generator. The thyristors are gated so as to decouple the generator from the mains

A stabilized control system and method for smoothly connecting and disconnecting an induction generator to the utility power grid is described. Thyristor switches are interposed between each phase of the mains and the generator. The thyristors are gated so as to decouple the generator from the mains for a period during each mains half-cycle, the decoupling period decreasing as the generator power factor angle increases as the generator is driven by the prime mover to its synchronous speed and above. A feedback circuit processes the generator terminal voltage to produce an analog feedback signal level proportional to the thyristor blocking voltage. The feedback signal is used to increase the thyristor gate delay angle as the generator voltage increases with increasing generator output power. This causes the rate-of-change of the generator voltage with respect to generator speed to be less than it would be with no feedback signal present. The result is increased stability margin and also reduced generator losses which increase the available generator power flow to the mains when the generator is operating at a small fraction of its rated output.

대표청구항 ▼

A controller for stabilized coupling of an induction generator to an alternating current (AC) power mains, comprising: switching means electrically connecting the power mains to the generator to transmit power therebetween, said switching means being adapted to switch on for current conduction betwe

A controller for stabilized coupling of an induction generator to an alternating current (AC) power mains, comprising: switching means electrically connecting the power mains to the generator to transmit power therebetween, said switching means being adapted to switch on for current conduction between the AC power line and the generator in response to a gating signal, and to switch off in response to a lack of current flow, adjustable control means connected to provide a gating signal to the switching means after a predetermined initial gate delay angle during each half cycle of the AC power mains voltage, means for sensing the switching means blocking voltage, and feedback means responsive to the sensed blocking voltage for adjusting the control means to progressively increase the gate delay angle as the generator power factor angle approaches the gate delay angle, the gate delay angle increasing at a lesser rate than the increase in power factor angle to stabilize transitions between motoring and generating modes of operation.