brushless dc motor controller commonly used control method are brushless dc motor controller is on the basis of a brush dc motor development, with stepless speed regulation, wide speed range, overload ability, good linearity, long life, small volume, light weight, large output, etc, to solve the motor controller, a series of problems, are widely used in industrial equipment, instruments and meters, household appliances, robotics, medical equipment and other fields. Due to no brush brushless motor controller for automatic reverse, so you need to use the electronic commutator for reversing. Brushless dc motor drive controller implementation is the function of the electronic commutator. At present, the mainstream of control method of brushless dc motor controller has 3 kinds: square wave control (Also known as the trapezoidal wave, 120 °, six steps commutation control)And sine wave control and FOC control (Also known as the vector variable frequency, magnetic field vector oriented control)。 Then the three kinds of control mode are each have advantages and disadvantages? Square wave to control the square wave control using hall sensor or non-inductive estimation algorithm to obtain the position of the rotor motor controller, and then according to the position of the rotor in the 360 ° electrical cycle, 6 reversing (Once every 60 ° the reversing)。 Each motor commutation position controller output power in a certain direction, therefore the position of the square wave to control precision is electrical 60 °. Because in this way under control, the phase current waveform close to square wave brushless dc motor controller, so called square wave control. Square wave control mode, control algorithm of the method is simple, low hardware cost, using ordinary controller can obtain high performance motor controller speed; The disadvantage is that large torque ripple, there is a current noise, can not reach the maximum efficiency. Square wave control is suitable for the controller of brushless dc motor rotation performance requirements is not high. Sine wave control sine wave control mode is used SVPWM wave, sine wave output is three phase voltage, the corresponding current is sine wave current. This way has no concept of square wave to control the reversing, or that an electrical cycle reversing the infinite times. Obviously, sine wave control compared to square wave control, the torque ripple is small, less current harmonic, control feels more 'exquisite', but the performance requirements of the controller is a bit higher than that of square wave to control, and efficiency of the motor controller can't play to the maximum. FOC control is realized the voltage sine wave vector control, indirect help to control the current size, but can't control the direction of current. FOC control mode can be thought of as an upgraded version of the sine wave control, realized the current vector control, which has realized the vector control of motor controller of the stator magnetic field. Due to the direction of the controller to control the motor stator magnetic field, so the controller can make the motor stator magnetic field and rotor magnetic field to keep at 90 °, achieve a certain electricity flow peak torque output. The advantage of FOC control mode is: small torque ripple and high efficiency, low noise, fast dynamic response. The disadvantage is that: the hardware cost is higher, the controller performance have higher requirements, motor controller parameters should be matched. Because of the obvious advantages of FOC, has in many applications gradually replace the traditional control mode, popular in the motion control industry.
