Research And Application On PWM Drive Technology Of Electro-hydraulic Proportional Valve

Electro-hydraulic proportional valve is one of the very important parts, as thestructure of the electro-hydraulic control system, and it is the interface elementbetween the electronic control and hydraulic control. Through the PWM drivingcircuit, it is very convenient to operate and process various input or output signals,and then realize complicated control function. In the electro-hydraulic proportionalvalve PWM drive circuit system, the electro-hydraulic proportional valve, as theperceptual load, at the same time because of the electronic device running intrinsicparameters and the influence of the leakage inductance, produces a large number ofburr peak in the process of PWM drive, and it seriously deteriorates the workingsurroundings of the proportional valve driver. At the same time, the proportionalvalve’s power supply is also one of the main interference sources of the driving circuit.People usually adopt DC regulated power supply, which increases the cost of thesystem.First, the electro-hydraulic proportional valve, drive technology development andstructure of the classification are introduced. The converter which is the corecomponent of electro-hydraulic proportional valve and the working and drivingprinciple of the converter are expounded.Second, the fundamental cause of EMI and its influence in detail during theelectro-hydraulic proportional valve PWM drive circuit are discussed. Combined withthe traditional EMI suppression circuit, it is through the analysis of the workingprocess of the MOSFET deeply that we can change the MOSFET gate drive resistance,make adjusting impulse signal which controls the proportional valve with a certainslope, thus the burr peak of the proportional valve driver circuit is improved.Again, it analyses the influence of the power supply voltage to the proportionalvalve PWM drive circuit, the regulated power supply is saved by the closed-loopcontrol driving circuit, thus make sure the system is protected from the interference ofpower disturbance. The input signal is step signal, the power is joined withdisturbance, and the simulation results show that the system output can be very goodto track the input signal and have good dynamic and static characteristics, which cansatisfy the electro-hydraulic proportional valve drive’s performance requirements.Finally, the electro-hydraulic proportional valve PWM driver is designed, and itgives the specific hardware circuit and software design. Through hydraulic winch speed test bench for drive test, the results show that the EMI interference technologystudied by the article can solve the burr peak of drive circuit well, and the closed loopcontrol drive circuit combined with the mature PI control strategy can achieve goodproportional valve power supply without regulated power supply.