PMSM/BLDC Motor Controller
1. Overview
BLDC motor/ PMSM has begun to replace the original asynchronous motors on the market on a large scale due to their energy-saving and high-efficiency characteristics, and are emerging in various industrial and household fields. Regarding the corresponding controller of the motor, the asynchronous motor does not require an additional controller to control it in an application environment that does not require speed regulation, and can be used directly by plugging in. When speed regulation or other related functions are required, a corresponding controller is required. Unlike asynchronous motors, all brushless DC motors/permanent magnet synchronous motors require a matching controller for control regardless of whether there is a speed regulation requirement.

2. Basic Control Principles
In the BLDC motor/ PMSM controller, the general low-voltage motor uses 6 power MOSFET tubes to form an electronic commutator as shown in Figure 2. MOSFET tubes VT1 and VT4 form the bridge arm of the brushless motor A-phase winding, VT3 and VT6 form the bridge arm of the brushless motor B-phase winding, and VT5 and VT2 form the bridge arm of the brushless motor C-phase winding. In any case, the upper and lower tubes of the same bridge arm cannot be turned on at the same time, otherwise the tubes will be burned out. By turning on the 6 power MOSFETs in sequence according to certain requirements, the 3-phase windings A, B, and C of the brushless motor can be energized in turn, and the motor can operate normally when the commutation requirements are met.

Generally, a high voltage motor controller will use 6 IGBTs as shown in Figure 3. Our engineers will make corresponding solutions based on customer needs.

Depending on whether the motor has a corresponding sensor, it can be divided into sensory control and sensorless control. According to the corresponding back electromotive force of the motor, it can be divided into square wave control and sine wave control.
On this basis, the controller will have various protection functions for the motor, such as overvoltage protection, undervoltage protection, overcurrent protection, undercurrent protection, overtemperature protection, etc.
3. Weak Magnetic Control
The BLDC motor/PMSM vector control technology has made great progress after decades of refinement. Nowadays, the vector control system of BLDC motor/ PMSM has reached a certain level, and the system stability, rapid response and speed tracking accuracy have been further strengthened and improved. However, in industries such as electric vehicles, ship power, and metal cutting that require motors to operate at high speeds, the motor vector control speed regulation system cannot meet the industry’s demand for motor speed, so weak magnetic control speed regulation has been gradually researched and developed.
Weak magnetic control not only inherits the excellent properties of closed-loop control of vector control, but also has a certain width of speed regulation range and smooth weak magnetic field transition characteristics. It basically meets the requirements for motor working conditions that require high-speed operation. As the times develop, the research and development of weak magnetic control has become particularly important. The hot issue of tapping the potential of motors has attracted extensive attention from scholars at home and abroad, and the weak magnetic control strategy has developed rapidly.
4. Summary
The above is some basic knowledge about BLDC motor/PMSM controller. In addition to standard BLDC motor/PMSM controllers, please contact us for specific project development. The development team will make matching designs based on customer requirements and application environment.