在挖掘机等工程机械中使用的嵌入式控制器普遍利用脉冲宽度调制(PWM)来驱动比例电磁阀。但由于 PWM 脉冲输出的特点和电磁阀自身电感特性的双重制约，使 PWM 驱动的比例电磁阀性能难以充分发挥，甚至会影响控制系统整体稳定性。因此，一种根据不同占空比改变 PWM 频率的方法被用于驱动比例电磁阀。控制器根据电磁阀控制需求的不同占空比，输出不同频率的 PWM。测试结果证明，使用变频率 PWM 驱动比例电磁阀的方法可以在保证比例电磁阀二次压力稳定的前提下，维持自身的小幅震荡，同时降低比例电磁阀的功率损耗。%In applications of excavator or other industrial machines,proportional electromagnetic valve was usually driven by PWM signals of embedded control system.However,due to pulse output characteristics of electromagnet,the performance of proportional electromagnetic valve was limited,e-ven impacted stability of the system.A frequency-varying method of PWM driving was proposed.Ac-cording to different duty ratio of PWM,the embedded control system output PWM with different fre-quencies.Through this method,the output oil pressure of proportional electromagnetic valve main-tains within a determinated range,the valve-core’s zero-average oscillations is reserved and power consumption of proportional electromagnetic valve is relatively low.
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