FIELD: electrical engineering.
SUBSTANCE: invention relates to electrical engineering and can be used in control systems of step motors (SM) in discrete electric drives. This technical solution can be used mainly when solving problem of determination of mechanical thrust of electric drive with bipolar step motor operating in full-step mode without loss of synchronism and installation of this drive into initial position. Method of determining the moment when mechanical stop is reached by a step motor is based on a characteristic change in the supply current of the driver when the rotor of the step motor meets an obstacle. To determine the mechanical thrust of the electric drive, the period of power supply pulsations of the unloaded electric drive driver is determined. During movement of the SM rotor towards the mechanical stop on the time interval containing at least two periods of pulsations of the power supply of the driver of the non-loaded electric drive and spaced from the moment of supply of the control signal to the time interval sufficient for change of polarity of current in the active phase of the step motor, period of pulsations of supply current of driver of step motor occurring after supply of control signal is measured. When this period exceeds the preset threshold value, a signal is generated, which is a sign of achievement of mechanical thrust by the electric drive. To implement the disclosed method, a device is developed. Expansion of the application area of the device is achieved by the possibility of its inclusion into the spent and operated control system of the drive without adjustment of the driver of the vehicle.
EFFECT: technical result is simplification and reduction of hardware and software costs, high noise immunity due to use of decision criterion, which sharply changes its value at approach of rotor of SM to mechanical stop.
8 cl, 6 dwg
