for most BLDC control system of motors, according to the available space and motor shaft of the convenience of installation, configuration and installation of sensors have many options. Figure 3 shows the ADA4571 two example configuration.
in figure 3. BLDC system with ADA4571 motors (a)The shaft end system (b)Axis side system
shaft end of a typical configuration includes a installed on the axis of rotation the diameter of the disc magnet magnetization, the magnet installed inside the motor assembly, as shown in figure 3 (a)Shown below. The magnet can provide a magnetic field through the sensor plane.
in this configuration, without having to make contact with mechanical and electrical components can directly read the rotor Angle. Because of AMR technology does not depend on the magnetic field intensity, so that can tolerate the air gap. Don't depend on the intensity of magnetic field can also increase mechanical tolerance and simplify magnet material choice.
the shaft end of the compact configuration means that the sensor can be installed directly in the very near the electronic control unit (Microcontrollers, MOSFET)The printed circuit board (PCB)Brushless dc motor, which can minimize signal routing and reduce the distance with severe motor environment.
another possible configuration is figure 3 (b)As shown in the axis of the system. Lateral axis configuration can be used for the shaft to be detected is not installed in the end the application of the magnet. In this configuration, provide incentives by magnetic ring, sensors and magnetic ring can be installed in any position on the shaft. Typical applications include electric power steering pump or because of the space limit cannot use BLDC motor motors at the shaft end.
since the ADA4571 provide low latency and accurate position feedback information, therefore can be precise control of motor current of each phase, so that the motor make smooth response to dynamic load, or maintain a constant speed under changing conditions. The end result is a better control, maximum torque, higher efficiency of start/stop, and the operation condition is better.
