The traditional electro-pneumatic PWM(pulse width
modulation) proportional valve driven by electro-mechanical converter of electromagnet has the disadvantages of slow response and poor control precision etc.To solve this
problem,a novel piezoelectric electro-pneumatic PWM proportional valve driven by the electro-mechanical converter of piezoelectric stack was presented,where its displacement
was amplified by the amplification mechanism based on flexure hinges.Then the
mathematical model of PWM proportional valve was set up.On this basis,a prototype was fabricated and its related test was researched.The effect of PWM carrier frequency,proportional control coefficient and flow load on the valve performance was analyzed. And the compound control method combined with pressure feedback,P control and PWM was applied to enhance the steady precision of valve.The experiments indicate that the valve has fast response and high steady precision,with good industrial application prospect.