Hardware Design For Controlling Drive Module Of Electro Hydraulic Braking System

Along with a new round of technological revolutions dominated by the Internet,large data and cloud computing.The auto industry has also shifted in the wave of technological revolutions.The traditional braking system has been replaced by electronic-hydraulic braking system.Which has become an irreversible trend in the direction of vehicle’s continuous development to electric,network,intellectualization and sharing.One of the core of the braking system is the research and development of the controller driving module,who’s driving performance is the main index to determine the braking performance of the vehicle.In this paper,the hardware requirement of PMSM is driven by electro-hydraulic braking system controller,the driver module of the controller is designed,and the driving module circuit with perfect hardware function,compact structure,high reliability and low cost is developed.Firstly,the research background,research significance and development trend of electro-hydraulic braking system controller are explained,as well as we also determine the research direction.In the aspect of requirement analysis,the design requirement of controller hardware was analyzed based on the requirement of product system,and the design requirement of controller driver module is further clarified.Based on the analysis of the system requirements and the selection of important components,the design of the driving module of the three-phase Full-bridge driving circuit using the pre-drive and MOSFET as the power switch device is finally determined.Secondly,the design of drive module’s core and peripheral circuit are designed,including protection circuit,current sampling circuit and power zone temperature sampling circuit.The rationality of the driver module design is validated by the worst case analysis(WCA),and the PCB drawing and prototyping are completed according to the design scheme.MOSFET as a driving circuit of the core components,its switching process produce power loss and warm the parts,the poor thermal performance can affect the function of the drive circuit and even damage.In this paper,the switching process of MOSFET is analyzed,the MOSFET loss model is established,the equivalent heat path model is established based on the two-sided heat dissipation method,the side-side heat dissipation model of MOSFET is designed,and the thermal analysis software Icepak is used to simulate the MOSFET junction temperature in the worst case.A reasonable external heat dissipation model is designed,and the rationality of the heat dissipation model is verified by experiments.At last,the driving module was tested,the experiment verifies the correctness of the lead signal of the pre-drive chip,the good following of the input and output signal of the driving circuit,the rationality of the dead time of MOSFET high and low side switch,and the reasonable driving resistance value was obtained through the MOSFET opening spike voltage test.By analyzing the experimental results,the synchronization of the parallel drive signal was verified,the influence of the driving resistance on the circuit was explained,and the power stability of the parallel operation was realized.