| The development of intelligent hydraulic control technology puts forward higher requirements for the performance of electro-hydraulic proportional valves.Electrohydraulic proportional valves are developing towards the direction of large flow rate,high frequency response,high reliability,intelligence,and integration.As the key component of electro-hydraulic proportional valve,the performance of the proportional solenoid determines the working characteristics of the valve.Research on the power driver of proportional solenoids is an effective way to improve the working performance of itself and even the characteristics of electro-hydraulic proportional valves.Aiming at the problem that the existing driving circuit is difficult to meet the dynamic response requirements of the high-power and high-response proportional solenoid,and is limited by the installation and heat dissipation requirements of the high-frequency response proportional valve.In this paper,a push-pull energy storage PWM power drive strategy is proposed,and a drive circuit is designed.The main research contents are as follows:(1)Based on the analysis of the research background and significance of the power drive circuit,the research status and development trend of proportional solenoid and its driving control technology are summarized.From the perspective of proportional solenoid function conversion relationship and time constant influencing factors,combined with the power driving requirements of proportional solenoid s,a push-pull energy storage type power driving strategy is proposed.(2)The principle of push-pull energy storage is expounded,the main circuit of push-pull energy storage power drive circuit is designed,and its specific working process is introduced in detail.From the theoretical level,the advantages of push-pull energy storage power drive over traditional power drive are discussed.The simulation model of push-pull energy storage power drive circuit is built,and its characteristics are analyzed from the simulation level.(3)With ARM as the core,the overall structure of the push-pull energy storage PWM power drive of the high-power high-frequency response proportional electromagnet is designed.Complete the hardware circuit construction and software program writing of the power drive.Combined with the reliability design of power drive,the prototype of push-pull energy storage PWM power drive is realized by using EDA software.(4)An experimental platform for push-pull energy storage PWM power drive was built,and hardware debugging and performance testing were carried out.The experimental results show that the driving circuit has strong current driving ability,great input and output characteristics.Its output current can reach up to 4A.For a highpower proportional solenoid with a current of 3300 m A,compared with the traditional single switch modulation and reverse discharging power drive circuits,the response time of the rising step is shortened by 24%,and the response time of the falling step is shortened by 94.6% and 45% respectively.The response speed of the proportional solenoid has been significantly improved.The push-pull energy storage power drive circuit accelerates the dynamic response of the proportional solenoid and improves its working characteristics.(5)A proportional pressure reducing valve test system based on push-pull energy storage power drive was established,and the steady-state and dynamic characteristics of the valve were experimentally studied.The results show that the proportional pressure reducing valve driven by push-pull energy storage PWM power driver has stable pressure regulation,good steady-state pressure control characteristics,and improved dynamic characteristics.The pressure step response time is shortened by 16.1%and 13.4% respectively compared with the traditional single switch modulation and reverse discharging power drive circuits.The push-pull energy storage power device can better meet the working requirements of the high-response proportional valve. |
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