Taking apart the motor controller of a brushless ceiling fan.

The motor rotor indicates that the motor power is about 35W, AC 230V, 50Hz, and the label clearly states the product is 'Made in India.' The plastic cover has threads and can be screwed onto the rotor body.

After opening the cover, we saw a huge PCB board – that’s the BLDC driver and power section. When we took off the PCB, we saw magnets on the inner surface of the outer rotor and the wound stator. The stator windings look hand-wound. Take a look at the details of the copper wire winding, everyone.

The basic block diagram of the whole circuit is roughly like this:

The low-voltage output section uses three RJ series 35V 1000μF 105℃ long-life 12000H high-frequency low-impedance capacitors from Nantong Sanxin Electronics, providing long-term operational reliability for the whole system in India's unique high-temperature environment.

The part circled in red in the picture is the ACDC, a standard flyback design. The red and black lines are AC input, followed by a fuse, varistor, and safety X capacitor, with no common-mode inductor.

Next, you can see that the high-voltage capacitor is a red CBB capacitor. Usually, people think conventional flyback high-voltage capacitors are big electrolytic ones, but the one in the picture is part of a high-PF flyback power supply, with a PF easily above 0.9, very low harmonics, and it easily meets various standards. 

The external high-voltage NMOS is a Toshiba K6A80E, 800V, 6A, RDS(ON) = 1.35 Ω (typ.).

There are also a lot of components on the back of the PCB, and the low-voltage side rectifier diodes are on the back too.

The bridge rectifier is MIC 12T10, probably 1.2A, 1000V.

The ACDC control IC is 28811, it might be UCC28811.

EE25 core, main winding inductance 330uH.

The optocoupler uses Wurth Electronics 814, and it's used to adjust the feedback control loop.

The ACDC converts 230V AC to 24V DC to power the motor. Also, a low-dropout LDO is used to provide a 3.3V supply for the MCU.

The brushless motor is driven using Texas Instruments' DRV10983. The DRV10983 is a three-phase sensorless motor driver with integrated power MOSFETs, capable of providing up to 2 A of continuous drive current. It has built-in presets and motor driving algorithms, and users can directly control the motor via PWM, analog signals, or I2C input. Motor speed feedback can be obtained through the FG pin or I2C interface. 

INABUCC70U23102300242 (QR code auto-detection)

The microcontroller is also connected to an infrared sensor for remote control and drives six LEDs, which can be used as night lights or to show the timer/fan speed status.