Input voltage control method

Abstract

The invention discloses an input voltage control method, which comprises a power supply, a first rectifying circuit and a second rectifying circuit, the first rectifying circuit and the second rectifying circuit are connected in parallel between the positive electrode and the negative electrode of the power supply and rectify the power supply, the output end of the first rectifying circuit is connected to a motor through a driving circuit, and the output end of the second rectifying circuit is connected to a controller through a voltage detection circuit. The controller collects a bus voltage value U real and a bus current value, stores a target duty ratio value D target and a target voltage value U target, determines the corresponding target voltage value U target according to the collected bus current value, and obtains an output control duty ratio D real to drive the motor according to a formula: D real = (U target * D target) / U real. By collecting the output voltage of the second rectifying circuit, the waveform is stable, the control effect is good, the duty ratio is changed according to the bus voltage, and stable operation of the motor is improved.

Description

【Technical field】 [0001] The invention relates to the technical field of motor control, in particular to a method for controlling the input voltage of a brushless motor. 【Background technique】 [0002] The existing AC brushless circuits all use large electrolytic capacitors, which make the motor control relatively simple, but the volume of large electrolytic capacitors is usually relatively large, which increases the volume of the circuit board. Therefore, the current conventional scheme adopts no large electrolytic capacitors, reducing Small size, and the circuit board has a long service life. However, since this circuit does not use large electrolytic capacitors and uses small-capacity capacitors, the bus voltage will change with the change of the load current after rectification. Usually, the controller needs to collect rectification After the voltage is controlled, the voltage input to the motor can be stabilized, but due to this change, the control effect of the brushle...

AI Technical Summary

Problems solved by technology

[0002] The existing AC brushless circuits all use large electrolytic capacitors, which make the motor control relatively simple, but the volume of large electrolytic capacitors is usually relatively large, which increases the volume of the circuit board. Therefore, the current conventional scheme adopts no large electrolytic capacitors, reducing Small size, and the circuit board has a long service life. However, since this circuit does not use large electrolytic capacitors and uses small-capacity capacitors, the bus voltage will change with the change of the load current after rectification. Usually, the controller needs to collect rectification After the voltage is controlled, the voltage input to the motor can be stabilized, but due to this change, the control effect of the brushless motor is affected, and due to the use of non-polar capacitors, the voltage fluctuation after rectification is easy to cause the input voltage supplied to the motor Fluctuation, and easy to trigger current protection

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