Research And Implementation Of Fractional Order PI~?D~? Controller Based On FPGA

The microprocessor-based digital PID(or PI~?D~?)controller changes the inflexible problem of traditional analog controllers,but the microprocessor has a long reset time(up to ms level)and poor field conditions.Fly the problem,affecting the control system stability and reliability.FPGA specific architecture can effectively improve the processor speed and reset time for the fractional PI~?D~? controller to achieve an effective way to achieve.In order to solve the problem that the mathematical expression of fractional PI~?D~?controller is complex and difficult to program,the expression of fractional PI~?D~?controller is transformed into matrix multiplication,and the lookup table in FPGA architecture is used to get output according to input address data(the data is pre-calculated and stored in the lookup table),the algorithm can improve the fractional PI~?D~? controller calculation speed and accuracy.The results show that the relative error of the algorithm is less than 0.3%,which is much higher than that of the traditional method.The speed closed-loop control system is constructed to verify the performance of the fractional-order PI~?D~? controller.The logic circuit module implemented in FPGA mainly includes the motor speed measuring module,the PWM wave generating module and the fractional PI~?D~? controller module.In order to improve the measurement accuracy of the speed and the dynamic performance of the system,a dynamic estimation method is proposed to realize the speed measurement of the motor.In order to improve the speed measurement of the motor,the rising edge of the control signal is not complete between the rising edge of the first measured pulse The use of direct digital synthesis technology(DDS)output sawtooth wave as a carrier to generate PWM wave and control the motor;the fractional number of the pulse The PI~?D~? controller is mainly composed of a register module,a lookup table module,a calculation matrix a module,and a control module.The results show that the functions of each module reach the expected target,and the output lag time of the velocity measurement result is less than 2 us,which realizes the high precision characteristic of the motor speed measurement.In this paper,we study and design the fractional PI~?D~? controller and measure the motor speed based on the dynamic estimation method.It has the advantages of improving the calculation and speed measurement of the fractional PI~?D~? controller,reducing the calculation time and speed measurerment delay of the fractional PI~?D~?controller,Which can improve the dynamic performance of the control system and provide a realization method for the fractional PI~?D~? controller,which has high engineering application value.