Abstract
In hybrid vehicles, there is the regenerative braking mode by traction motor during deceleration. In this state, the conventional hydraulic braking with the regenerative braking makes the total braking force of the vehicle. Therefore, it is necessary to control hydraulic brakes cooperatively with regenerative braking to meet the total braking force. In this paper, the smart booster system which replaces vacuum booster with PMSM driven stroke based hydraulic pressure generator is proposed to enable controlling hydraulic brake force in hybrid vehicles. This system consists of a brake pedal, a smart booster module, ECU, hydraulic lines and wheel brake modules. For controller design, the maximum brake force is estimated and PI current controller is used for PMSM torque control. To verify suitability of the proposed system for hybrid vehicle, the fundamental experiment was executed on a gasoline vehicle. And the evaluation result shows that the proposed system is effective as the braking system for hybrid vehicle.
Keywords: Smart booster, ECU(Electronic Control Unit), Regenerative brake, PMSM(Permanent Magnet Synchronous Motor)