Research On New Control Algorithms Of Two-Phase Hybrid Stepping Motor

Stepper motor is a kind of machine that transforms an electrical pulse signal into the corresponding angular displacement. Because it has the advantages of low price, easiness to control and high accuracy, stepper motor has been widely used in machinery, instrumentation, offical automation equipment and other fields. With the development of science and technology, permanent magnetic materials develop rapidly. Hybrid stepping motor with higher energy density has come into being.Microstepping drive technology not only inhibits the low-frequency oscillation and overshooting of stepper motor to some extent, but also improves the step accuracy. It has been widely used in actual industrial production. The traditional microstepping drive technology always uses analog circuit to implement the functions. But the hardware circuit is complex, and it's less flexible, transplantable and expandable.This paper describes three new control algorithms of two-phase hybrid stepping motor which are implemented digitally. The first, this paper introduces an open-loop vector microstepping drive system of two-phase hybrid stepping motor. Because of the characteristics of the motor's position in open-loop, a single current loop can be constructed using the discrete angle and synthetic current vector. Then the motor is driven at various microstep states to verify the algorithm. Secondly, the paper introduces the chopper control of two-phase hybrid stepping motor based on three-phase inverter. The paper analyzes various states of 6 switches after linking two windings. And this algorithm uses high-frequency chopper to control the direction and amplitude of two-phase winding's current. The experiment proves that it can drive two-phase hybrid stepping motor in a variety of operating modes successfully. The third, in order to improve the disadvantages of the second technology, SPWM control of two-phase hybrid stepping motor based on three-phase inverter is introduced. Three-phase inverter is also used, but this algorithm needs the coordinate transformation and decoupling operations of two-phase current. And it controls two-phase current with particular SPWM modulation.