The Design Of Digital 3-phase HB-type Stepping Motor Driver

Stepping motor has no accumulative error, high positioning accuracy and low cost advantages, is widely used in motion control field. As digital chip processing ability has increased and aspires of high quality and low cost driver system, the manufacturing of a digital driver work perfectly, which has practical significance obviously.In this paper, three-phase stepping motor working principle and structural characteristics is analyzed, to lay the theoretical foundation for driver design and obtains that the hybrid stepper motor is the mainstream in the future development, with the advantages of both reactive and excitation type stepping motor.This paper introduces PWM technology of current tracking PWM, sinusoidal pulse width modulation(SPWM) and voltage space vector pulse width modulation(SVPWM) in detail. The current tracking PWM is one type of feedback current follow reference voltage handling, has the advantages of simple control and realization of analog circuit with MCU; SPWM and SVPWM handling process more, with DSP as its processing units regularly. The output SPWM wave of regular sampling method has the high harmonic components and the low voltage utilization rate, However, SVPWM method is widely used for its high voltage utilization rate.For the realization of vector pulse width modulation, taking TMS320F28031 as the processing unit in this paper, digital stepper motor driver compatible with twophase stepper motor is established and the software written based on SVPWM is fulfilled. This paper clearly presents the implementation of hardware and software each module, and the completed analog driver of current tracking type is compared.Finally, the analysis draw that digital driver not only can drive two-phase stepper motor simultaneously, with a broad hardware platform applicability; but also the phase current is similar to sine wave in low speed and motor rotation steadily, and solve the analog driver at a low subdivisions inevitable oscillation phenomenon, further validates the advantages of the voltage vector control method and the feasibility of hardware and software scheme.