Research On High Performance Closed-loop Drive System For Two-phase Hybrid Stepping Motor

The two-phase hybrid stepping motor is widely used in the fields of industry and consumer electronics because of its simple control,accurate positioning and low cost.In the traditional application situation,the control of the stepping motor is mainly based on open loop control,its shortcoming are low frequency oscillation,no high speed,poor load-bearing capacity,lost step and so on.In recent years,with the continuous development of modern industrial applications,people put forward higher and higher requirements on the stepping motor application occasions,higher precision,dynamic response speed and improve load-bearing capacity has become a new research hotspot.So it has practical engineering significance and theoretical significance to study the control system of stepping motor in order to improve the control performance.Firstly,on the basis of the operation mechanism of stepping motor and the permanent magnet AC servo system closed-loop control mechanism in this paper,the mathematical model of the stepping motor is derived under the dq coordinate system and the principle block diagram of the closed loop control system is confirmed.An especial control mode based on the up and down bridge complementary conduction and the diagonal bridge conduction at the same time is designed by analyzing topological structure of double H bridge inverter,and a space voltage vector pulse width(SVPWM)modulation method is re-derived based on double H bridge inverter by using three-phase SVPWM modulation mode for reference.The integral separation PI controller is also designed at the same time.Closed-loop control structure with current loop / speed loop as the inner loop and position loop as the outer loop is introduced,and the high performance closed-loop drive system of the two-phase hybrid stepping motor is finally formed.Secondly,in order to verify this scheme's feasibility.The closed-loop control system simulation model based on matlab / simulink is established.The system comprises a motor body model,SVPWM model,integral separating PI regulator model,Park transform and its inverse transform and so on.Among them,the SVPWM model and the integral separating PI regulator model are mainly used in the M language.At the same time,the system model is simulated and analyzed from several aspects,and the feasibility of the design is finally proved.Then,combining with the control algorithm of this paper,the hardware of the drive system is designed.It comprises control core and its peripheral circuit,double H bridge inverter circuit,PWM isolation drive circuit,current sampling and over current protection circuit,external signal input / output circuit and communication circuit and so on.Among them,the TI C2000 series DSP chip TMS320F28035 is used for the control core.In addition,the sampling and over current protection circuit is simulated with multisim because of the importance of circuit security.Its results show that the circuit can be protected well.Finally,two-phase hybrid stepping motor high performance closed-loop drive system control program is compiled with C language by module-design idea.Among them,it comprises the SVPWM algorithm program,the rotor incipient position location program,the encoder decode program,the current sampling program and the integral separation PI program.At the same time,the necessary experiment and analysis are carried out.The experimental results show that correctness,feasibility and superiority of the control strategy proposed in this paper is finally proved.