| 摘要 |
PURPOSE:To provide a highly reliable protection method which can reduce the drop of the power efficiency in parallel operation of an uninterruptive power unit. CONSTITUTION:At parallel redundant operation of an uninterruptive power unit, each arm of an inverter 5 is provided with fuses 22u-22z, and if it detects a short circuit 10, it cuts off a faulty uninterruptive power unit from a sound parallel operation apparatus by turning off a changeover circuit by this detection signal, and also, turning on or turning off the switching elements 18u, 18y, 18w, 18y, and 18z of the U, V, W, Y and Z phases excluding the short-circuit arm of, for example, X phase with proper timing. |
