The market needs more and more Variable Speed Drive (VSD) motor control for better efficiency. Electric motor-based home appliances increased from 420 million pieces in 2011 to 514 million pieces in 2016, and in the meantime, the VSD penetration market share increased from around 20% to 40%.
For instance, in refrigerators where a PSM motor has been the standard for a long time, a permanent magnet 3-phase BLDC is more and more designed to decrease power consumption. For a designer, this requires new knowledge and expertise. But thanks to Infineon I-motion, no C code is necessary, greatly simplifying the design and minimizing risks.
For a Field Oriented Control, designers have to apply relatively complex mathematics and perform matrix calculation. In a standard solution, this must be programmed. The performance of the microcontroller is very important, but the way the code is written is also critical. In Infineon’s solution, only some parameters must be configured, as the loop for Field Oriented Control is hardwired and hence no C code is necessary. Thanks to this innovative architecture, even a newcomer to 3-phase motor control design will have the motor spinning within a few minutes, and new configurations can be tested almost on the fly.
The iMotion™ solution from Infineon is a full system solution. This means, software is available to configure the Motor Control Engine, along with the microcontrollers and all of the power section. The power section can be discrete with standalone gate drivers and MOSFETs or IGBTs, or all these devices can be included in a module.
The iMotion™ controller itself is in fact split in 3 sections:
- The Microcontroller
- Motion Control Engine (MCE) – configuration section for the sensorless control engine
- Analog Signal Engine (ASE) – Signal processing and ADC
The iMotion™ portfolio has several levels of complexities. The IRMCK099 is a Motion Control Engine, while the IRMCK1/3 or the IRMCF1/3 families integrate a Motion Control Engine and a Microcontroller. Finally, the IRDM982 and 3 combine the Motion Control Engine, the Microcontroller and the Power Stage. A more or less integrated solution will fit a solution depending on current requirements. Indeed, a product like the IRDM983 coming in a Power-QFN 12x12 mm2 will dissipate less heat than a customized design that takes all the necessary space on a board to optimize power dissipation.
Functions are already hardwired, so no C code to implement. All the constants parameters can be changed for the performance. The coding for a BLDC is not trivial, and only powerful microcontrollers can perform the required tasks. For instance, the program continuously must perform matrix calculations. Indeed, the system must transform the 3-phase 120 degree reference frame (for calculation of currents in each coil) to 2-axis orthogonal reference frame (for physical position of the motor). This is called the Park transform. iMotion gets rid of this hurdle.
In order to calculate parameters, the wizard tool is a big help.
After the welcome page, a list of questions about the motor, DC bus, operational amplifiers, temperature requirements, motor parameters, some protection requirements or the kind of desired PWM pops up. In the end, the parameters can be exported as a header file for a C code or as a simple text file.
Once done, the MCE Designer tool will make the motor spin. The parameters file saved previously in a txt format can be imported.
As shown in the Motor window, functions to start and stop the motor are available, and the designer is ready to test the design, again without having to write any C code.
To conclude, thanks to iMotion™ development platform from Infineon, all the pieces, hardware and software are available to spin a high power BLDC motor in a few minutes. This process previously required extensive knowledge and tedious embedded programming tasks right at the beginning. iMotion™ saves engineers days of trying to achieve the right configuration that optimizes Variable Speed Drive (VSD) motor control.