Benefit of The Asymmetrical half Bridge on Proportional valve Electronic Control

Electronically controlled proportional valves are widely used in hydraulic controls both in mobile and industrial applications. Standards for earthmoving machines and for agricultural machines are considered in order to increase safety in mobile applications. In order to increase safety, the classic proportional valves control method is modified. A double control using both high side and low side driver in "asymmetrical half bridge" configuration is used. The solution increases valve control performance: by actuating a PWM control simultaneously in both drivers, the electric coil charge and discharge time are strongly reduced and the electrical effects due to continuous switch of electrical power increase the differential voltage on coil terminals, allowing current recirculation from power source. A simulation is performed and a real control stage is designed, a board is realized and tested both on bench for electric performance evaluation and on a real valve, comparing performance and verifying stage safety.