Energy efficiency is a vital criterion for developing any electronic or electrical device. Lower energy use means higher cost savings, which can make or break the fortunes of a business that relies on machinery on a day-to-day basis. Brushless Permanent Magnet Machines (BPMM) are designed to maximize energy efficiency and minimize losses. One of the best implementations of Brushless Permanent Magnet Machines is a brushless permanent magnet motor. Mostly found in cylindrical shapes, a BLDC motor has electrical windings on the stator and permanent magnets on the rotor. Due to the stationary windings on these motors, no electrical contacts such as brushes are required. Therefore, these motors are popularly known as Brushless DC motors.
Fundamental Attributes of BPMM
BPMM are categorically divided into AC and DC machines. It is possible to design both AC motor permanent magnet and DC permanent magnet machines as Surface Permanent Magnet (SPM) Machines or Interior Permanent Magnet (IPM) Machines. For a permanent magnet brushless DC motor machine, the back EMF has a trapezoidal waveform. It uses a shaft-position sensor with low resolution to synchronize the switch of the drive transistors with the rotor position. For AC motors, the waveform is sinusoidal.
Common Attributes of Brushless Permanent Magnet DC Motor:
· Have concentrated windings and full pitched · Come with trapezoidal back EMF · Use the hall sensor board to detect the correct switching position · Higher power density · Tolerance to torque ripple · No extra field weakening is required · Ideal for power drives
The Designing of High-Efficiency Brushless Permanent Magnet Machines and Driver Systems
To design a brushless permanent magnet motor and Driver System, one has to consider many factors related to permanent magnet brushless dc motor drives and controls. Let’s take a glance at the design process:
Selecting the appropriate material
Select the best material in terms of high magnetic permeability and low losses for the stator and rotor cores. It is preferred if you use laminated cores and quality magnetic steel as they can drive down the losses significantly. It is worth noting that permanent magnet brushless motors for RC boats work well because of their high-grade material.
Writing down the exact specifications
The design can never be right if it does not cover the requirements accurately. You must jot down the speed range, power rating, torque output, and size constraints before beginning the design process.
Selecting the topology of BPMM that needs to be built
Only after looking at the requirements, you can choose the most beneficial BPMM topology. For instance, you can select the appropriate topology between surface-mounted or interior permanent magnets based on your needs.
Figuring out the magnetic design
To determine the magnetic design, you need to ponder upon the magnet’s size, type, shape, and arrangement. It is advised that you use Finite Element Analysis (FEA) tools to optimize the magnetic circuit for delivering max flux density and minimum cogging torque.
Coming up with the right stator design
You should design the slots and stator windings to minimize losses due to the resistance of windings and iron losses. Scrupulously arranging slots and windings and choosing the ideal winding material for insulation is crucial.
Management of thermals
Efficient heat dissipation can help in maintaining high efficiency and stopping overheating. Integrate cooling fans, or bring in liquid cooling systems to control temperature rise in both the driver and the machine.
Tuning the efficiency
Utilize cutting-edge control strategies to optimize efficiency under different load conditions. It is advisable to use techniques such as field-oriented control (FOC) to increase torque output while reducing losses.
Driver System Design
Along with the machine/motor, one needs to design a high-performance Driver (Inverter) system to transform DC power into three-phase AC power, which is needed to drive the brushless permanent magnet electric motor. You must choose apposite semiconductor devices such as IGBTs, MOSFETs, SiC, and GaN along with the correct control algorithms. After that, you need to implement sensor less control techniques for position and speed estimation to minimize system intricacy.
Final Thoughts
High-efficiency brushless permanent magnet machines and driver system can only work well if it is designed while keeping every consideration mentioned above in mind. Only the top permanent magnet motor supplier keeps all the considerations at the forefront of their thoughts and delivers motors that work as intended. Therefore, always procure the machines from a permanent magnet dc motor supplier if you want to leverage the true efficiency of these highly productive motors.