Brushless motor control code quickly generate principle and structures,
model based design method using Mathworks provides a series of tools, can be achieved directly from design concept to the algorithm model, and then automatically generated by the model of embedded code efficient development process. For this example, on LPC2124 chip to achieve brushless motor control (刷)State of transformation, the designers do not need to consider how to motor in C or assembly language, only pay attention to the algorithm itself, to complete the work tedious code generation to computer. This can greatly shorten the product development cycle, improve work efficiency.
1 principle analysis of brushless dc motor work leave the electronic switch circuit, so the ontology by motor, rotor position sensors and electronic switching circuit of three parts, the brushless dc motor control system, its structure diagram is shown in figure 1. Dc power supply power to the motor stator winding through the switch circuit, position sensor detecting the rotor position at any time, and according to the position signal to control the switch tube conduction and globe, model aircraft, motor windings which winding electricity, which is automatically controlled by power outages, implements the electronic commutation.
figure 1 brushless motor control system structure diagram below in a three-phase winding brushless motor as an example, a brief introduction to its working principle. Figure 2 for three-phase full bridge drive circuit principle diagram, with the method of two common electric drive to its, the two winding electricity at the same time. Figure contains six three-phase inverter circuit composed of transistors, diodes, Ha, Hb, Hc for rotor position signal of hall element of feedback. Control circuit will be determined according to the position signal 6 road PWM signal on and off, which makes the power tube conduction or shut off, the winding conduction in a certain order, continuous rotation drive motor. when using two phase conduction way drive motor, the power tube of the situation after 1/6 cycle (conduction on or offThe 60 & deg; ）。 Embedded on the inside of the brushless dc motor has three hall position sensor, they differ on the space & 120 deg; 。 Due to the rotor is a permanent magnet motor, when it is in the rotation, the magnetic field will change form a rotating magnetic field, each hall sensors generate 180 & deg; The pulse width of the output signal.
figure 2 three-phase full bridge drive circuit principle diagram V1, assuming that the current power tube V6 conduction, into the motor, the current from A phase from phase C motor, the magnetic field generated by the electricity flows through the winding direction is (A，C）。 由A和C的合磁场产生的转矩使转子转动到AC位置。 The rotation of the rotor to make the output of the hall sensor changes, control circuit will adjust power tube conduction, will switch off V6, V5 conduction. At this time, the current from A photograph into the motor, flowed from B phase motor, the magnetic field generated by the winding direction is (A，B）。 由A和B的合磁场产生的转矩使转子转动到AB位置。 Similarly, hall device can output a different value, control circuit to make corresponding processing, complete a full phase of the cycle.
