This reference design from Renesas is a single board inverter based on RX111 device from the powerful 32-bit RX microcontroller family. It also includes a low-voltage MOSFETs power stage and a communication stage. The reference design enables engineers to drive a 3-phase Permanent Magnet Synchronous Motor ( PMSM) or AC brushless motor using an advanced sensorless Field Oriented Control algorithm. The reference design can be used to make motor drivers for drones, compressors, air conditioning, fans, air extractors, pumps and industrial drives, etc.
The advantage of the design is that it is simpler and more economical. The reference design allows the user to monitor and tune various parameters using the Graphical User Interface provided by the company. The reference design is highly customizable and allows the user to select the best switching frequency and control frequency to adapt the control dynamics suitable to the application requirements. This enables any designer to make the right compromise between system dynamics, CPU load and overall efficiency
The reference design allows calibrating of any 3-phase Brushless AC/DC motors using an Auto-tuning procedure. The reference design can be used in a sensorless mode which reduces the design complexity. For example, it employs three shunt resistors for the phase current measurement rather than an expensive current sensor, therefore, driving down the BoM cost and number of components. This reference design is compatible with other existing Motor Control Reference Platform with external power stage delivering up to 1.5KW at 230VAC.
Figure showing screen of the GUI (Source: Renesas)
Features of the Reference Design
- Memory Footprint: 30 KB Flash / 3 KB RAM
- PWM Frequency: 16 kHz
- Control loop Frequency: up to 16 kHz
- CPU time available: 45%
- Auto-tuning PI current: Enable by default
- Motor calibration: Enable by default
- Flux weakening algorithm: Enable by default
- Voltage bus monitoring: Enable by default
- Fail-safe mechanism: Enable by d