CN204669254U - BLDC motor control assembly in blower fan filtering unit - Google Patents

Abstract

The utility model discloses BLDC motor control assembly in a kind of blower fan filtering unit, comprise switch element, detecting unit, comparing unit and logical circuit, wherein, described switch element is connected with stator coil in BLDC motor, and powers to stator coil; Described detecting unit is used for the back electromotive force detecting stator coil when Hall element fault; Described comparing unit is used for the back electromotive force of the stator coil in BLDC motor and reference voltage to compare, and exports result to described logical circuit; Described logical circuit is connected with Hall element, for judging the operating state of Hall element, and controls described switch element break-make according to the Output rusults of comparing unit, and then control BLDC motor action.The utility model can guarantee the normal work of BLDC motor in described blower fan filtering unit.

Description

BLDC motor control device in fan filter unit

Technical Field

The utility model relates to a controlling means, in particular to BLDC (Brushless direct current) motor control device among fan filter unit.

Background

The brushless dc motor applied to the fan filter unit includes a stator coil (U-phase, V-phase, W-phase, respectively), a permanent magnet, and a rotor. The drive circuit of a brushless dc motor supplies a current to a stator coil, which generates a magnetic field based on the current to rotate a motor mover. The motor continuously rotates towards one direction, and the current flow direction can be judged by detecting the position of the rotor, so that whether the change-over switch is turned on or turned off is determined.

As shown in fig. 1, the brushless dc motor is composed of a BLDC motor main body 100 and a motor driving circuit 200, the BLDC motor main body 100 includes three stator coils 130, a permanent magnet 120, and hall sensors 110 for detecting the magnetic field strength of a rotor, and specifically, the hall sensors 110 have three groups, i.e., first, second, and third hall sensors 110a, 110b, and 110c, respectively.

The phase difference between the input and output signals of the first, second and third hall sensors 110a, 110b, 110c is 180 °, that is, two signals Hu⁺And Hu^-，Hv⁺And Hv^-，Hw⁺And Hw^-Is 180 deg., the first, second and third hall sensors 110a, 110b, 110c output a signal Hu⁺，Hv⁺，Hw⁺The phase difference therebetween was 120 °.

The motor driving circuit 200 receives the signal output from the hall sensor 110 and generates a three-phase reference signal, and the generated three-phase reference signal excites the three stator coils 130 to generate a magnetic field, thereby controlling the permanent magnet 120 to rotate. Specifically, the motor drives electricityThe circuit 200 includes a reference signal generating unit 220 for receiving an output signal of the hall sensor 110 and a controller 240 corresponding thereto, wherein the reference signal generating unit 220 receives a signal (Hu)⁺，Hu^-；Hv⁺，Hv^-；Hw⁺，Hw^-) And outputs the reference signals isou, isov, isow to the controller 240. However, since the hall sensor 110 is susceptible to the ambient temperature, it is prone to malfunction, and the reference signals isou, isov, isow output by the reference signal generating unit 220 are inaccurate, which affects the BLDC motor.

SUMMERY OF THE UTILITY MODEL

The utility model provides a BLDC motor control device among fan filter unit to solve the above-mentioned technical problem who exists among the prior art.

In order to solve the technical problem, the utility model provides a BLDC motor control device in fan filter unit, which comprises a switch unit, a detection unit, a comparison unit and a logic circuit, wherein the switch unit is connected with a stator coil in the BLDC motor and supplies power to the stator coil; the detection unit is used for detecting the back electromotive force of the stator coil when the Hall sensor fails; the comparison unit is used for comparing the back electromotive force of the stator coil in the BLDC motor with a reference voltage and outputting the result to the logic circuit; the logic circuit is connected with the Hall sensor and used for judging the working state of the Hall sensor and controlling the switch unit to be switched on or switched off according to the output result of the comparison unit.

Preferably, the stator coil is provided with three groups of u-phase, v-phase and w-phase coils.

Preferably, three groups of hall sensors are provided.

Preferably, the switch unit has three sets, and each set controls three sets of stator coils.

Preferably, the comparison unit comprises three sets of comparators.

Preferably, the logic circuit comprises a controller and an alarm, and the controller is connected with the Hall sensor, the comparison unit, the detection unit, the switch unit and the alarm.

Preferably, the alarm adopts a warning lamp or a buzzer.

Preferably, the controller is a single chip microcomputer, a PLC or an MCU.

Compared with the prior art, the BLDC motor control device in the fan filtering unit comprises a switch unit, a detection unit, a comparison unit and a logic circuit, wherein the switch unit is connected with a stator coil in the BLDC motor and supplies power to the stator coil; the detection unit is used for detecting the back electromotive force of the stator coil when the Hall sensor fails; the comparison unit is used for comparing the back electromotive force of the stator coil in the BLDC motor with a reference voltage and outputting the result to the logic circuit; the logic circuit is connected with the Hall sensor and used for judging the working state of the Hall sensor and controlling the on-off of the switch unit according to the output result of the comparison unit so as to control the action of the BLDC motor. The utility model discloses a set up logic circuit and detect hall sensor's action state, the back electromotive force through detecting element detection stator coil simultaneously utilizes the back electromotive force of stator coil in the comparing element with the BLDC motor to carry out the comparison with reference voltage, comes the control switch unit and then controls the action of BLDC motor according to this comparative result at last, ensures the normal work of BLDC motor among the fan filter unit.

Drawings

Fig. 1 is a schematic structural view of a BLDC motor in the related art;

fig. 2 to 3 are schematic circuit diagrams of a BLDC motor control device in a fan filter unit according to an embodiment of the present invention.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be noted that the drawings of the present invention are simplified and use non-precise ratios, and are only used for the purpose of facilitating and clearly assisting the description of the embodiments of the present invention.

As shown in fig. 2 and fig. 3, the BLDC motor control device in the fan filtering unit of the present invention includes: a switching unit 210, a detection unit 220, a comparison unit 230, and a logic circuit 240. Wherein,

the switching unit 210 is connected with a stator coil A, B, C in the BLDC motor and supplies power to the stator coil A, B, C;

the detection unit 220 is used for detecting the back electromotive force of the stator coil A, B, C when the hall sensors Ha, Hb and Hc are in failure;

the comparison unit 230 is configured to compare the back electromotive forces un, vn, wn of the stator coil A, B, C in the BLDC motor with a reference voltage n, and output the result to the logic circuit 240;

the logic circuit 240 is connected to the hall sensors Ha, Hb, and Hc, and is configured to determine working states of the hall sensors Ha, Hb, and Hc, and control on/off of the switch unit 210 according to an output result of the comparing unit 230.

Specifically, with continued reference to fig. 2 and 3, the switching unit 210 rotates the rotor of the BLDC motor by applying three-phase voltages to the three stator coils A, B, C of the BLDC motor. Referring to fig. 3, the detecting unit 220 is configured to detect back electromotive forces generated in three stator coils A, B, C in the BLDC motor, that is, u-phase, v-phase, and w-phase coils of the BLDC motor, when the three hall sensors Ha, Hb, and Hc fail. Three Hall sensors Ha, Hb and Hc in the BLDC motor output 1 or 0 digital signals according to the rotating directions of an N magnet and an S magnet in the BLDC motor. The comparing unit 230 is configured to compare the back electromotive forces un, vn, wn of the u-phase, v-phase, and w-phase coils with a reference voltage n, and output first, second, and third switching signals Hall a, Hall B, and Hall C according to a comparison result. The logic circuit 240 receives digital signals sent by the three Hall sensors Ha, Hb, and Hc, determines whether the Hall sensors Ha, Hb, and Hc have a fault according to the received digital signals, and controls the switching unit 210 according to the first, second, and third switching signals Hall a, Hall B, and Hall C output by the comparing unit 230.

Specifically, when the logic circuit 240 receives that the level voltages of the three output signals sent by the three hall sensors Ha, Hb, Hc are equal, the three hall sensors Ha, Hb, Hc are in a fault state. That is, when the output signals of the three hall sensors Ha, Hb, Hc are in (1, 0, 1), (1, 0, 0), (1, 1, 0), (0, 1, 0), (0, 1, 1), (0, 0, 1)6 states, it is indicated that the hall sensors Ha, Hb, Hc are in a normal state; when the output signals are (0, 0, 0) and (1, 1, 1), that is, when the output signals have the same voltage level, the hall sensors Ha, Hb, and Hc are in a failure state. When the hall sensors Ha, Hb, Hc are in a fault state, the logic circuit 240 controls the BLDC motor to operate according to the back electromotive force of the three stator coils A, B, C detected by the detection unit 220, so as to ensure the BLDC motor to operate normally. Meanwhile, the logic circuit 240 can also give an alarm when the three hall sensors Ha, Hb and Hc have faults, so as to remind a user of paying attention, so that the BLDC motor can work normally.

Preferably, the logic circuit 240 includes a controller and an alarm, the controller is connected to the alarm, the switch unit 210, the detection unit 220, the comparison unit 230 and the hall sensors Ha, Hb, Hc, and is configured to receive data information in the detection unit 220, the comparison unit 230 and the hall sensors Ha, Hb, Hc, and control the switch unit 210 and the alarm, and the alarm may be a warning light or a buzzer.

As shown in fig. 2 to fig. 3, the control method of the BLDC motor control device in the middle blower filtering unit of the present invention is:

firstly, Hall sensors Ha, Hb and Hc detect the initial position of a rotor;

three-phase currents are applied to the three sets of stator coils A, B, C in the BLDC motor to rotate the rotor, generating a counter electromotive force.

The logic circuit 240 obtains the position of the rotor in the BLDC motor through the detection of the three hall sensors Ha, Hb, and Hc, and the detection unit 220 detects three groups of back electromotive forces.

The logic circuit 240 determines whether the three hall sensors Ha, Hb, Hc are operating normally. Specifically, when the output signal level voltages are equal in the three hall sensor BLDC motors, a fault state is present in the hall sensor BLDC motor.

When a fault state occurs in the hall sensor BLDC motor, the rotation of the BLDC motor is controlled according to the counter electromotive force of the sensing unit 220, and the logic circuit 240 provides an alarm indication to a user for the subsequent BLDC motor to be operated normally.

It will be apparent to those skilled in the art that various changes and modifications may be made to the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention belong to the same technology, it is intended that the present invention also include such modifications and variations.

Claims (8)

1. A BLDC motor control device in a fan filtering unit is characterized by comprising a switch unit, a detection unit, a comparison unit and a logic circuit, wherein the switch unit is connected with a stator coil in the BLDC motor and supplies power to the stator coil; the detection unit is used for detecting the back electromotive force of the stator coil when the Hall sensor fails; the comparison unit is used for comparing the back electromotive force of the stator coil in the BLDC motor with a reference voltage and outputting the result to the logic circuit; the logic circuit is connected with the Hall sensor and used for judging the working state of the Hall sensor and controlling the on-off of the switch unit according to the output result of the comparison unit.

2. The control device for the BLDC motor in the fan filter unit of claim 1, wherein said stator coil is provided with three groups of u-phase, v-phase and w-phase coils.

3. The fan filter unit BLDC motor control device of claim 2, wherein said hall sensors are provided in three groups.

4. The control device for the BLDC motor in the fan filter unit of claim 2, wherein said switching unit is provided with three sets for respectively controlling three sets of stator coils.

5. The control device of the BLDC motor in the fan filter unit of claim 1, wherein said comparison unit comprises three sets of comparators.

6. The control device of the BLDC motor in the fan filter unit of claim 1, wherein the logic circuit comprises a controller and an alarm, and the controller is connected to the hall sensor, the detecting unit, the comparing unit, the switching unit, and the alarm.

7. The control device of the BLDC motor in the fan filter unit of claim 6, wherein the alarm is a warning lamp or a buzzer.

8. The BLDC motor control device of claim 6, wherein the controller is a single chip, a PLC, or a MCU.