CN-116221166-B - Brushless fan PAM controller and method based on single-phase bridge type phase control rectifier

CN116221166BCN 116221166 BCN116221166 BCN 116221166BCN-116221166-B

Abstract

The invention belongs to the technical field of brushless fan control, in particular to a brushless fan PAM controller and a method based on a single-phase bridge type phase control rectifier, the controller separates rotation speed control and commutation control, the rotation speed control part uses single-phase bridge type phase control rectification, and the commutation control part uses a sensorless control scheme based on a three-phase inversion bridge arm framework. Specifically, the single-phase bridge type phase control rectifying part converts single-phase alternating current input into direct current output, and current closed loop is realized by adjusting the conduction angle of the thyristor, so that the rotating speed closed loop of the brushless fan is realized. Under the condition of single-phase alternating current input power supply, a single-phase bridge type phase control rectifier is used, so that two parts of the rectifier and the DC/DC converter in the traditional framework can be replaced, the cost is saved, the complexity of a circuit structure is reduced, and the efficiency and the reliability are improved. In the commutation control part, sensorless commutation control of the brushless fan is realized through a motor line voltage sampling circuit, a driving circuit and a three-phase bridge arm inverter circuit, and the problem of delay commutation of the traditional back electromotive force method is solved.

Inventors

CHEN LI
WU YUHAN

Assignees

施默赛恩科技(苏州)有限公司

Dates

Publication Date: 20260508
Application Date: 20230321

Claims (8)

1. A brushless fan PAM controller based on a single-phase bridge phase-control rectifier, comprising: The single-phase bridge type phase control rectifier adopts a current loop control mode, and realizes the regulation of output current by controlling the conduction angle of a thyristor so as to control the rotating speed; the reversing control circuit conducts corresponding windings correspondingly by utilizing position feedback of the rotor to conduct reversing control; The output end of the single-phase bridge type phase control rectifier is connected with the input end of the reversing control circuit; The reversing control circuit comprises a three-phase inverter bridge arm circuit, a motor line voltage sampling circuit and a driving circuit; the motor line voltage sampling circuit is used for acquiring the rotor position in real time, and driving the on and off of six switching tubes of the three-phase bridge arm through the driving circuit according to the expected value of the rotor position and the feedback actual value of the rotor position; the motor line voltage sampling circuit is used for scaling and filtering the collected motor line voltages through two operational amplifiers, and then comparing the three motor line voltages in pairs through a hardware comparator to obtain reversing points, so that the reversing control of the motor is realized.
2. The single-phase bridge phase-controlled rectifier-based brushless fan PAM controller of claim 1, wherein the single-phase bridge phase-controlled rectifier comprises four thyristors, two being a group, each group being 180 degrees out of phase, closed loop control of the output current being achieved by controlling the conduction angle of each group.
3. The PAM controller of a brushless fan based on a single-phase bridge phase-controlled rectifier according to claim 2, wherein an output end of the single-phase bridge phase-controlled rectifier is connected in parallel with a freewheeling diode and a voltage stabilizing capacitor.
4. The brushless fan PAM controller based on the single-phase bridge type phase control rectifier according to claim 1, wherein the three-phase inversion bridge arm circuit comprises six MOS tubes, two MOS tubes are combined into a group to form a three-phase bridge arm, and inversion is realized by controlling the on or off of the six MOS tubes in one period.
5. The brushless fan PAM controller based on the single-phase bridge type phase-control rectifier according to claim 1, wherein the driving circuit is used for obtaining a reversing point by comparing the voltages of all motor lines, and driving six MOS transistors of the three-phase inverter bridge arm is completed by the bootstrap circuit.
6. The PAM controller of a brushless fan based on a single-phase bridge phase-control rectifier of claim 5, wherein each phase leg of the three-phase inverter leg has an upper MOS transistor and a lower MOS transistor, wherein a source S of the lower MOS transistor is grounded, and a source S of the upper MOS transistor is suspended and output to a gate of the MOS transistor through a bootstrap circuit to drive the three-phase inverter leg.
7. The brushless fan PAM controller based on a single-phase bridge phase-control rectifier according to claim 1, characterized in that the single-phase bridge phase-control rectifier comprises two PI controllers and a phase-control rectifier bridge, and the closed-loop control of the motor rotation speed is realized by controlling the conduction angle of thyristors in the rectifier bridge; the commutation control circuit adopts a sensorless scheme based on motor line voltage, the motor line voltage obtains a commutation signal after passing through the sampling circuit, and the three-phase inversion bridge arm is controlled by the driving circuit to realize commutation control.
8. A brushless fan PAM control method based on a single-phase bridge phase-controlled rectifier, characterized in that the control method is used for controlling the brushless fan PAM controller based on the single-phase bridge phase-controlled rectifier according to any one of claims 1 to 7, and comprises the following steps: s1, in a strong dragging stage, controlling the bus current of a motor to be stabilized at a set value, and simultaneously controlling six switching tubes of a three-phase inverter bridge arm to periodically and sequentially switch, so that the frequency of switching on the switching tubes is increased, and the motor is started; S2, in an autonomous reversing stage, through motor line voltage sampling, switching on a switching tube of a three-phase bridge arm according to a result obtained by comparison of a hardware comparator, and controlling bus current to drive a motor to accelerate; and S3, in a rotating speed closed loop stage, the rotating speed control of the motor is completed according to the rotating speed set value and the actual rotating speed of the motor.

Description

Brushless fan PAM controller and method based on single-phase bridge type phase control rectifier Technical Field The invention relates to the technical field of brushless fan control, in particular to a brushless fan PAM controller based on a single-phase bridge type phase control rectifier and a method thereof. Background With the progress of modern technology, brushless fans are widely applied in the fields of industry, household appliances, ships, aerospace, energy and the like. In the industrial field, brushless fans are applied to centrifugal air compressors for fuel cells, turbochargers, industrial blowers, and the like. The brushless fan used in the fuel cell has the rotating speed of 10 ten thousand revolutions, and the motor can convey a large amount of clean air for the fuel cell system and provide enough oxygen for the reactor reaction, thereby improving the efficiency of the fuel cell. In the field of home appliances, high-speed brushless fans are widely used in electric blowers, cleaners, air conditioners, and the like. The high-speed dust collector can quickly suck up dust attached to the ground. The Dyson blower has the rotating speed of 11 ten thousand revolutions, and can provide strong wind power to quickly dry the hair. The application of the high-speed brushless fan in the field of household appliances greatly improves user experience, improves use comfort, and more users now start to select the household appliances using the high-speed brushless fan. The electromagnetic torque of a brushless fan is generated by the interaction of the current in the stator windings and the rotor magnetic field, i.e Wherein T em is electromagnetic torque, omega is motor mechanical rotation speed, Therefore, the electromagnetic torque is proportional to the current amplitude, so that the electromagnetic torque of the brushless fan can be controlled by controlling the amplitude of the output current. The relationship between the electromagnetic torque, the load torque and the rotational speed of the brushless fan can be described by the mechanical motion equation of the motor: wherein T L is load torque, B is damping coefficient, and J is moment of inertia. For fan type loads, the load torque is proportional to the square of the rotational speed, i.e.: TL＝Cω2 Wherein C is a constant, depending on the load. When the rotating speed of the brushless fan reaches a stable state, the electromagnetic torque T em is equal to the load torque T L, and the rotating speed of the brushless fan can be controlled by controlling the amplitude of the output current. The traditional control mode of the middle-low speed brushless fan is generally a PWM modulation mode, namely, on the basis of a three-phase bridge arm inverter circuit, the rotating speed control and the reversing control of the motor are realized by PWM control on a switching tube. However, because the inductance value in the high-speed brushless fan is lower, the PWM modulation mode can generate more harmonic components, so that the torque pulsation of the motor is increased, and the operation is not stable enough. Because the inductance value of the high-speed brushless fan is smaller, the PAM control mode is more suitable for the high-speed brushless fan, as shown in fig. 2, the motor rotation speed control and the commutation control are separated, the front stage of the PAM control mode is a current source, the rotation speed control of the motor is completed by controlling the amplitude of the output current, and the rear stage is a three-phase inverter circuit and is responsible for the commutation control of the motor. However, when the power grid is used for alternating current power supply, the traditional motor controller based on the PAM structure needs rectification, DC/DC conversion and three-phase inversion bridge arm three-level structure, which can cause the problems of rising cost, reducing efficiency, reducing reliability and the like of the controller, and the circuit of the traditional PAM structure needs to be improved. The control strategy of the brushless fan can be divided into a control scheme with a position sensor (hereinafter referred to as "sensorless") and a control scheme without a position sensor (hereinafter referred to as "sensorless"). The inductive control scheme is to install a Hall sensor and the like in a motor spindle, detect the position of a rotor by means of the position sensor, and calculate the rotating speed of the motor rotor and the reversing time of the motor according to the information obtained by the position sensor. But installing the position sensor in the high-speed brushless fan greatly reduces the reliability and stability of the motor operation. Because of the high rotating speed, high electric frequency, quick temperature rise, electromagnetic radiation, high temperature and other factors of the high-speed brushless fan. It is possible that the position sensor may not function properly. The sensorles