The FU68 series MCU incorporates an integrated FOC core computation module, facilitating highly efficient single-phase sensorless drive with minimal peripheral circuitry requirements. This advanced single-phase sensorless sinusoidal drive solution is primarily utilized in household appliances, such as hair dryers and vacuum cleaners. Currently, the domestic market predominantly features two types of single-phase motors: the single-phase AC motor and the sensored single-phase BLDC motor. While the former exhibits lower overall efficiency, its cost is comparable to that of the latter, which is inconsistent with the prevailing trend towards energy conservation and emission reduction. The sensored single-phase BLDC motor solution is constrained by the limitations of position sensors, and the traditional square-wave drive solution generates electromagnetic noise during motor operation, thereby restricting its applicability in environments with stringent requirements.

This solution mainly introduces the features and application methods of FU68 series single-phase sensorless sinusoidal MCU solution and the control features and functions of example programs.

Introduction:

This solution generates a sinusoidal waveform based on the motor phase current while effectively addressing the challenge of position estimation in single-phase motors. In contrast to the traditional single-phase sensored square-wave control solution, the single-phase sensorless sinusoidal solution demonstrates significantly broader applicability, enabling precise motor control across a wide range of speeds. Currently, it supports motor control with a maximum electrical speed of up to 210,000 RPM. Furthermore, the sensorless sinusoidal solution ensures stable torque control, effectively mitigating noise caused by torque fluctuations. This results in superior performance, enhanced compatibility, and a more refined operational experience.

Features:

• Solidified sinusoidal algorithm and fast operation: FU68 series MCU implements all   sinusoidal computations in hardware, saving software runtime. With a  maximum PWM frequency of 40 kHz, it is suitable for high-speed motors (>210,000RPM);

• High control accuracy and efficiency: The electrical angle 360° expanded to2^15 and the angular resolution reaching 0.01° can realize high accuracy control to the motor; the upgraded position estimation algorithm can realize high efficiency control;

• Low noise: FOC algorithm accurately controls drive current waveform as smooth sinusoidal waveform reduces torque impulse and also implements ultra-mute operation;

• Smooth and fast startup: This solution ensures startup reliability and stability via load torque varying adjusting startup torque and mode; Startup time is 50% shorter than that of normal startup mode;

• Simple hardware circuit: The chip integrates high-speed operational amplifier, high-voltage LDO, and minimal peripheral circuitry to lower the product cost and improve the reliability of the system.

We own the exclusive patent, details are as follows:

Application:

Features of the exampled program based on single-phase sensorless sinusoidal drive solution are showed below:

1. FU68 series IC

2. Startup Control

(1) Quick startup with 600ms speed at highest

(2) Detect motor initial state and realize dynamic startup (including tailwind and headwind detection)

(3) Set the largest startup current

3. Speed Control

(1) Open-loop speed control, convert to current frequency and set V/F curve parameters according to a given speed

(2) Speed regulation interface: SREF/PWM/IR/UART

4. State Display

LED indicates the system's operational status (Normal/Fault).

5. Protection Control

(1) Over-voltage protection: The over-voltage protection is triggered when the voltage is higher than the over-voltage threshold and the system restarts when the voltage is lower than the restore threshold

(2) Under-voltage protection: The under-voltage protection is triggered when the voltage is lower than the under-voltage threshold and the system restarts when the voltage is higher than the restore threshold

(3) Over-current protection: The over-current protection is triggered when the current is higher than the over-current threshold and you can set restart times

(4) FO protection: The hardware over-current protection is impulsed by large current and the system will not restart

(5) Over-temperature protection: The over-temperature protection is triggered when the temperature is higher than the over-temperature threshold and the system restarts when the temperature is lower than the temperature restore threshold

6. User Interface

(1) Key interface: Define key interface and provide Key command. You can define Key command, like ONOFF control command

(2) SREF interface: Provide potentiometer value for ADC sampling and give SREF commands. You can define SREF command, like ONOFF control command, open-loop PWMDuty reference value, open-loop Speed reference value

(3) PWM interface: Capture PWM signal, gain PWMDuty, give PWM command. You can define PWM command, like ONOFF control command, open-loop PWMDuty reference value, and open-loop Speed reference value

(4) IR interface: Define infrared interface. Provide IR command after receiving infrared data, like ONOFF control command, open-loop PWMDuty reference value, and open-loop Speed reference value

(5) UART interface: Provide UART command after receiving UART data. You can define UART command, like ONOFF control command, open-loop PWMDuty reference value, open-loop Speed reference value

(6) Buzzer interface: Define buzzer interface. Realize alarm or warning after receiving control command from Buzzer. You can define Buzzer command, like key warning control

7. Debugging Interface

Under the default functional settings, the program provides the Customer.h document as your debugging interface. You shall only modify the corresponding parameters to achieve general motor control functions.