基于CY8C24533的电动自行车设计.ppt

* 现在大家看到的是PSoC的结构图，整个系统是由MCU核，Memory，数字系统，模拟系统，和其他系统资源组成。 左面的部分是普通单片机的结构，包含时钟源，Flash，SRAM和MCU本身。 右面的部分就是PSoC特色，请看桔黄色的部分，这就是可编程数字模块和模拟模块，PSoC的优势也正是在这里。 This slide is the block diagram of the demo board. This is a low voltage BLDC control platform, the input power supply is 24V. 3phase low voltage invert is included on the board. This board can support both sensored and sensorless control algorithm. For sensored control, an interface on the board to connect with the HALL sensor from the motor. White for sensorless control, the board provides a signal condition circuit to sample the BEMF signal. An potentiometer on the board can be used for the speed command input, and two button on the board for start/stop, forward/reverse control. Other on-board peripherals like UART interface for communication and LCD for information display As we introduction before, current control is very important in motor control. Especial for the over-current detection. The over-current protection implemented by hardware can quickly response and avoid the over-current damage to the power device. This slide we introduce the how to design the over-current protection by hardware. Usually in the control circuit, there is a shunt resistor for the current sampling. The voltage drop on the shunt resistor is compared with a PSoC internal reference voltage through the PSoC comparator, which is formed by a CT module. The comparator output signal will be inverted by the LUT module on comparator bus. Through the digital buffer which is formed by a digital block, the comparator output signal can AND with the PWM signal before output to the I/O. When current low than limit value, the comparator will output low and through the inverter change to high, then it will enable the PWM signal output to IO. when over-current scenario occurs, then the signal change to LOW and disable PWM output to I/O. This slide show the implemented of the circuit I presented in last slide into PSoC. Point out the comparato