Method of controlling input voltage

A method of controlling an input voltage, applied to control operation of a motor, the method performed by a motor control circuit, the motor control circuit comprising:

• a power supply, a first rectifier circuit connected between a positive terminal and a negative terminal of the power supply, and a second rectifier circuit connected between the positive terminal and the negative terminal of the power supply,
• wherein the first rectifier circuit and the second rectifier circuit are connected in parallel with each other, an output end of the first rectifier circuit is connected to the motor via a driver circuit;
• an output end of the second rectifier circuit is connected to a controller through a voltage detection circuit;
• and
• wherein the method comprises:
• collecting, by the controller, a bus current value;
• and collecting, by the controller based on the voltage detection circuit, a bus voltage value Ureal output from the second rectifier circuit, wherein the controller stores at least one target duty cycle value Dtarget and at least one target voltage value Utarget;
• determining, by the controller, one of the at least one target voltage value Utarget based on the collected bus current value to obtain an output control duty cycle Dreal based on a formula:
• Dreal=(Utarget*Dtarget)/Ureal to drive the motor to control the input voltage of the motor;
• wherein a capacitor is connected in parallel with and between the output end of the first rectifier circuit and the driver circuit, both the voltage detection circuit and the capacitor are connected to the ground, the first rectifier circuit comprises four diodes, and two diodes of the second rectifier circuit and two diodes of the four diodes in the first rectifier circuit are shared by the second rectifier circuit and the first rectifier circuit.