Intelligent brake control system circuit design based on DSP embedded technology

　　In terms of hardware circuit design, DSP chip and peripheral circuits are used to form the speed capture circuit. The motor drive controller uses microcontroller chip and peripheral circuits to form current sampling, overcurrent protection, pressure regulation and other circuits. CPLD is used to realize the logical commutation of the rotor position signal of the brushless DC motor. The racing brake controller is composed of an anti-skid controller and a motor drive controller. Both controllers are based on DSP chips. The anti-skid controller mainly controls the slip rate and outputs a given brake pressure. The DSP chip is used as the CPU, and the racing car and wheel speed signal conditioning circuit is added. The motor drive controller mainly adjusts the brake pressure and controls the motor current. The DSP chip is used as the CPU, and the peripheral circuits such as motor current feedback conditioning circuit, overcurrent protection circuit, brake pressure conditioning circuit, and four sets of three-phase full-bridge inverter circuits constitute the motor drive controller.

　　Signal processing circuit: The anti-skid controller of a racing car mainly controls the slip rate to prevent the car from slipping. The pressure reference value is output after adjusting the deviation of the slip rate to track the given slip rate. The anti-skid controller must have a conditioning circuit for the speed signal of the front wheel and brake wheel of the racing car, mainly to obtain the feedback slip rate. The racing car speed signal is replaced by the speed signal of the front wheel of the racing car that is rolling freely. Speed ​​sensors are installed on the front wheel and brake wheel of the racing car. When the wheel rotates, the speed sensor generates an AC signal in the form of a sine wave. For each rotation of the wheel, the speed sensor sends a 50-cycle sine AC signal. The amplitude of the sine AC signal changes with the change of the wheel speed. The signal is a sine wave signal with a bias voltage of 2.5V, a peak value of 0.3V, and a maximum signal amplitude not exceeding 5V.

　　Current sampling and overcurrent protection circuit: The current of the brushless DC motor is detected through the resistor on the bus of the power drive circuit. The resistor on the bus is composed of two 0.01Ω power resistors in parallel. The sampling circuit samples the current through these two parallel sampling resistors. The sampling resistor converts the current signal into a voltage signal, which is sent to the current monitoring chip for amplification, and then filtered by the second-order active filter circuit composed of OPA2344. Finally, the current feedback signal is obtained and sent directly to the A/D converter.

　　The hardware overcurrent protection circuit plays an important role in the normal operation of the system, mainly protecting the power device MOSFET and the motor. The system also has a software protection function. The overcurrent signal OVCURX is sent to the input pin of the DSP. When OVCUR is high, the DSP will generate the motor control rotation signal ENABLE to shut down the logic signal and stop the motor. The chip IR2130 itself has an overcurrent protection function.

　　The design of the racing car brake control system has been completed, mainly focusing on hardware design and control strategy research. In terms of design, high-speed DSP chips and CPLD are used and their peripheral circuits are designed. The system also designs a drive circuit with IR2130 as the core, a current signal hardware amplifier circuit, a filter circuit and a protection circuit, a pressure signal amplifier circuit and a filter circuit, a racing car speed and wheel speed processing circuit, etc. In terms of control strategy, fuzzy control is used to adjust PID parameters.