| 摘要 |
PURPOSE:To suppress the noise of a compressor by using signals from the outputs of a real time I/O port as ON-OFF control signals of switching elements. CONSTITUTION:Outputs (U phase - W phase) of a real time I/O port 11 are inverted after the lapse of time of real time data from the start of a timer. Pulse trains U-W obtained by the inversion and the inverted pulse trains x-z are used as ON-OFF control signals of switching elements 2. The values of the real time data can be set arbitrarily, the time intervals between the phases of the pulse trains U-W, x-y can be set at about several micro seconds, and especially the pulses having the width of several micro seconds can be obtained at the positions corresponding to the vicinities of zero crossings of a carrier wave due to the accuracy of the timer. Therefore, when a compressor 1 is controlled by the inverter, the current wave shapes of the compressor 1 can be approximated to sinusoidal wave shapes more precisely. |
