ABSTRACT
The frequency domain method is commonly used in the design and the correction of a fluid power servo system. The premise for utilizing this method is that transfer functions or the describing functions of all the elements are known. The describing function of the PWM high-speed on-off valve, therefore, must be discovered in order to use the frequency domain method. As mentioned above, its characteristics is described by the four time domain parameters, and no direct relationship between them can be seen. This paper tries to propose a method by which the relationship between them can be discovered. Based on this method, the influences of the switching behavior of the valve and the carrier frequency on its frequency response characteristics are fully studied. And some conclusions are obtained, which are useful for the designer to identify the high-speed on-off valve correctly during his designing.
