TWI395874B - Fan system and brake circuit thereof - Google Patents

Description

Fan system and its brake circuit

The present invention relates to a fan system and a brake circuit thereof, and more particularly to a fan system that uses a control unit to send a reverse rotation control signal to control the fan system to stop rotating and its brake circuit.

In recent years, the use of digital-based microcontrollers (MCUs) combined with power electronic switch drive circuits for electronic product design has become a common technology in the industry. However, when the electronic product is operated, the digital microcontroller and the power electronic switch may generate a large amount of heat due to the high frequency operation; therefore, the heat dissipation requirement of the electronic product will become a very important design issue.

At present, the more common heat dissipation method is to drive the heat of the electronic product by the operation of the fan system. However, based on the fan control and the safe operation of the user, the fan system usually combines a stall circuit to power off the power supply. When the fan system is stopped, the accuracy of the fan control and the safety of the user are ensured.

As shown in FIG. 1, a conventional fan system and its braking circuit are disclosed, including a bridge driver 91, a control unit 92, a storage capacitor 93, an immediate stop unit 94, and a motor coil 95. One of the voltage sources VCC is coupled to the bridge driver 91, the control unit 92, the storage capacitor 93, and the immediate stop unit 94 to provide the power requirements of the components described above. The bridge driver 91 has two upper bridge electronic switches M91 and M94 and two lower bridge electronic switches M92 and M93. The instant stop unit 94 has two electronic switches M95 and M96 for respectively connecting and controlling the bridge driver 91. Two lower bridge electronic switches M92, M93; the control unit 92 has four control outputs respectively connected to the instant stop unit 94 two electronic switches M95, M96 and two other electronic switches M97, M98; the motor coil 95 One end is connected to the bridge driver 91 above the bridge electronic switch M91 and the lower bridge electronic switch M93 are connected to each other; the other end is connected to the bridge driver 91 the other upper bridge electronic switch M94 and the other The bridge electronic switch M92 is connected to each other.

When the voltage source VCC normally supplies power to the fan system, the control unit 92 generates a set of control signals from the control output thereof, and controls the bridge driver 91 and the immediate stop unit 94 to operate, so that the bridge driver 91 The upper bridge electronic switch M91, M94 and the two lower bridge electronic switches M92, M93 form an alternating conduction to control the current on the motor coil 95 to form an alternating current; for example, the electronic switches M91 and M92 form a conduction, and the The other two electronic switches M93 and M94 form an open circuit so that the current flows in the motor coil; otherwise, the current is controlled to flow backward in the motor coil. In addition, the storage capacitor 93 continues to be charged until a predetermined amount of power is supplied.

When the voltage source VCC is interrupted, the control unit 92 no longer provides a control signal to the bridge driver 91 and the immediate stop unit 94 to operate, so that the two electronic switches M95 and M96 of the instant stop unit 94 form an open circuit; The storage capacitor discharges, because each of the conduction control terminals (such as the gate terminal of FIG. 1) of the second bridge electronic switches M92 and M93 of the bridge driver 91 is connected to the storage capacitor 93, thereby making the bridge driver The 91nd second lower bridge electronic switch M92, M93 can be turned on according to the power supply of the storage capacitor 93, so that the two ends of the motor coil 95 have the same potential, so that the fan system stops immediately.

However, in general, the above-mentioned conventional use has the following disadvantages, for example, the fan system needs to be controlled by the immediate stop unit 94 during power-off to perform an immediate stop operation. In contrast, the fan system is bound to increase the circuit connection complexity, increase the control complexity, and increase the circuit installation cost due to the setting of the immediate stop unit 94. For the above reasons, it is necessary to further improve the above conventional fan system and its braking circuit.

The object of the present invention is to improve the shortcomings of the above-mentioned conventional fan system and its braking circuit. When one of the control units reverses the operation of the control signal, the input voltage of the fan system is interrupted, and a motor brake is immediately executed. To simplify the control of the stop control circuit and the complexity of the circuit connection.

A second object of the present invention is to provide a fan system and a brake circuit thereof, wherein a motor is braked by a control unit to reduce the circuit installation cost of the fan system.

The fan system according to the present invention comprises: a motor, a motor drive circuit and a control unit. The motor driving circuit is electrically connected to the motor; the control unit is electrically connected to the motor driving circuit; when an input voltage is supplied to the fan system, the control unit generates a forward rotation control signal to control the motor in a predetermined direction Rotating; when the input voltage interrupts power supply to the fan system, the control unit generates a reverse rotation control signal that controls the motor to rotate in a direction opposite to the predetermined direction.

The stop control circuit of the fan system according to the present invention includes a control unit that generates a forward rotation control signal to control the rotation of the motor in a predetermined direction when an input voltage is supplied to the fan system; When the voltage is interrupted to supply to the fan system, the control unit generates a reverse rotation control signal that controls the motor to rotate in a direction opposite to the predetermined direction.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

Referring to FIG. 2, a fan system and a brake circuit thereof according to a preferred embodiment of the present invention are disclosed. The fan system includes a motor drive circuit 1, a control unit 2, a motor 3, and an energy storage unit 4. An input voltage VCC is electrically connected to the motor driving circuit 1, the control unit 2 and the energy storage unit 4 through a diode D. In other words, the motor driving circuit 1, the control unit 2 and the energy storage unit 4 are electrically connected. Connected to one of the cathodes of the diode D, such that the input voltage VCC can be supplied through the diode D to provide power for the components.

The motor drive circuit 1 is composed of a plurality of electronic switches, and the motor drive circuit 1 is electrically connected to the motor 3 to form a full bridge drive circuit or a half bridge drive circuit, and the electronic switch of the motor drive circuit 1 The number is determined by the phase number system of the motor 3, and each of the electronic switches has a controlled end to receive a turn-on or turn-off switching signal.

The control unit 2 can be selected from a microcontroller or a motor drive IC, the control unit 2 comprising a plurality of control outputs, the plurality of control outputs forming a control output group 21 of the control unit 2, the control The plurality of control outputs of the output group 21 are electrically connected to the plurality of electronic switches of the motor drive circuit 1 respectively, so that the control unit 2 can output a set of forward rotation control signals or a set of reverse rotation control signals to control the The switching operation of the plurality of electronic switches of the motor drive circuit 1 performs the forward/reverse control of the motor 3.

Furthermore, the control unit 2 further includes a voltage detecting terminal 22, and the voltage detecting terminal 22 is electrically connected to the input voltage VCC for detecting abnormality of the input voltage VCC. In addition, in order to enable the voltage detecting terminal 22 of the control unit 2 to receive a voltage signal, the voltage detecting terminal 22 of the control unit 2 can be electrically connected to the diode through a voltage converting unit 5 . D one of the anodes and receives the input voltage VCC. The voltage conversion unit 5 can select a voltage dividing network, and the input voltage VCC can output the voltage signal suitable for the rated voltage of the control unit 2 by using the voltage dividing network (for example, converting a 12V input voltage VCC into a partial voltage) A voltage signal of 3V is input to the control unit 2) to prevent excessive voltage from directly impacting the control unit 2. Furthermore, since the voltage conversion unit 5 is electrically connected to the anode of the diode D, and the energy storage unit 4 is electrically connected to the cathode of the diode D, the voltage conversion unit 5 can be connected to the diode The body D blocks the discharge voltage of the energy storage unit 4 to avoid affecting the conversion accuracy of the voltage conversion unit 5.

Referring to FIG. 3, it is disclosed that the motor 3 of the preferred embodiment of the present invention is a three-phase system motor, for example, may be selected from a three-phase brushless DC motor. The motor driving circuit 1 is provided with a three-arm switch group in cooperation with the phase number of the motor 3. The first arm switch group is formed by connecting two electronic switches 11 and 14 in series, and has a first series connection point A; the second arm switch The group is formed by two electronic switches 13 and 16 connected in series and has a second series connection point B; and the third arm switch group is formed by connecting two other electronic switches 15 and 12 in series, and has a third series connection point. C. Furthermore, the six electronic switches 11-16 of the motor drive circuit 1 are respectively selected from the transistor switches, and the six electronic switches 11-16 each have a controlled end 111, 121, 131, 141, 151. And 161, each of the controlled terminals 111-161 can individually receive the rotation control signal to control whether each of the electronic switches 11-16 is turned on or off. In addition, each of the controlled terminals 111, 131, and 151 of the electronic switches 11, 13, 15 of the bridge on the motor driving circuit 1 is separately connected to a transistor switch M1, M2, and M3, and the transistor switches M1 and M2 are respectively connected. And the operation of M3 to control the operation of the electronic switches 11, 13, 15 of the bridge on the motor drive circuit 1.

Referring to FIG. 3 again, the control output group 21 of the control unit 2 cooperates with the phase number of the motor 3 to set six control outputs 211, 212, 213, 214, 215 and 216, and the six control outputs. The two end switches 211 216 216 are connected to the six electronic switches 11 16 , the control unit 2 can generate the rotation control signal, and the rotation control signal is fed into the six electronic modes through the six control outputs 211 216 216 The switches 11 to 16 perform on or off control of the six electronic switches 11 to 16.

Referring to FIG. 3 again, the three-phase motor 3 of the present invention has three coils 31, 32, 33. The first coil 31 has a first output end 311 and a first input end 312. The second coil 32 has a second output end 321 and a second input end 322. The third coil 33 has a third output end 331 and a third input end 332. The respective output ends 311, 321, and 331 of the three coils 31, 32, and 33 are connected in common to form a Y-type connection; and the first input end 312 of the first coil 31 is connected to the third arm switch group. a third series connection point C, a second input end 322 of the second coil 32 is connected to the second series connection point B of the second arm switch group, and a third input end 332 of the third coil 33 is connected to the first arm The first series connection point A of the switch group.

When the input voltage VCC of the fan system of the present invention is normal, and the control unit 2 transmits the normal voltage signal (for example, 3V) converted by the voltage conversion unit 5 through the voltage detecting terminal 22, the control unit 2 Sending the forward rotation control signal to the six electronic switches 11-16, and switching the six electronic switches 11-16 to perform the coils 31, 32, 33 of the motor 3. Current direction control. Thereby, the control of the forward rotation control signal of the control unit 2 causes the motor 3 to rotate in a predetermined direction (for example, to rotate in a clockwise direction). At the same time, the input voltage VCC stably supplies power to the energy storage unit 4 and is accumulated to a predetermined amount of power.

However, when the input voltage VCC of the fan system of the present invention is abnormal due to the voltage drop, the control unit 2 detects that the voltage conversion unit 5 converts an abnormal voltage signal through the voltage detecting terminal 22, and the abnormal voltage is generated. When the signal is lower than the abnormality determination voltage value (for example, 2.4V) preset by the control unit 2, since the energy storage unit 4 is electrically connected to the control unit 2, at this time, the energy storage unit 4 is discharged for the control. The unit 2 continues to operate, so that the control unit 2 sends the reverse rotation control signal to the six electronic switches 11-16 to control the rotation direction of the motor 3 to rotate in the opposite direction (for example, Turn counterclockwise) so that the motor 3 of the fan system stops immediately.

The present invention comprises a periodic signal comprising a plurality of timings, and the reverse rotation control signal and the reverse rotation control signal are configured in mutually opposite timing arrangements, and the following further relates to the use of the forward rotation control signal and the reverse rotation control Signal, detailed description of the motor 3 brake control mode of the fan system: Please refer to FIGS. 3 and 4, which discloses that the motor 3 of the fan system of the present invention is driven by a six-step square wave, the motor 3 coils 31, 32 The current change on the 33 shows a cyclical change of the six timings S1 to S6. In the operation of the sequence S1, the control unit 2 controls the two electronic switches 11 and 12 to be turned on, and the other four electronic switches 13 to 16 are turned off, so that the current is passed from the third input terminal 332 of the third coil 33. Flowing in, from the first input terminal 312 of the first coil 31, and defining a current flowing out of the first coil 31 as a negative current, and a current flowing into the third coil 33 is defined as a positive current, and at the timing In S1, no current passes through the second coil 32, and accordingly, the current waveforms of the coils 31, 32, and 33 of the sequence S1 in Fig. 4 can be obtained.

Similarly, in the operation of the sequence S2, the control unit 2 controls the two electronic switches 12 and 13 to be turned on, and the other four electronic switches 11 and 14 to 16 are turned off, so that the current is caused by the second coil 32. The second input terminal 322 flows in, and flows out from the first input terminal 312 of the first coil 31, and defines a current flowing out of the first coil 31 as a negative current, and a current flowing into the second coil 32 is defined as a positive current. At this timing S2, no current passes through the third coil 33, and accordingly, the current waveforms of the coils 31, 32, 33 of the sequence S2 in Fig. 4 can be obtained correspondingly.

Similarly, the operation of the timing S3 is performed by turning on only the two electronic switches 13 and 14; the operation of the timing S4 is performed by turning on only the two electronic switches 14 and 15; The two electronic switches 15 and 16 perform the operation of the sequence S5; and the operation of the timing S6 is performed by turning on only the two electronic switches 16 and 11.

In this way, when the power supply is normal, the control unit 2 of the present invention can sequentially plan the forward timing of the forward rotation control signal for the timings S1 to S6, and control each of the electronic switches 11 to 16 to be turned on or off for each timing control. The motor 3 is sequentially operated in accordance with the timing S1, the timing S2, the timing S3, the timing S4, the timing S5, and the timing S6, thereby controlling the motor 3 to rotate in the predetermined direction.

Furthermore, when the power supply is abnormal (such as a power interruption), the control unit 2 of the present invention can program the reverse timing of the reverse rotation control signal in reverse order for the timings S1 to S6, that is, if the power interruption occurs in the timing In S1, the sequence S6, the sequence S5, the sequence S4, the sequence S3, the sequence S2, and the sequence S1 are sequentially operated, thereby controlling the rotation direction of the motor 3 to rotate in a direction opposite to the predetermined direction, so that the fan system The motor 3 stops immediately.

Referring to Figures 2 and 5, the motor 3 of the preferred embodiment of the present invention is disclosed as a single phase system motor. The motor drive circuit 1' is provided with a two-arm switch set in conjunction with the number of phases of the motor 3, wherein the first arm switch group is formed by connecting two electronic switches 11' and 14' in series, and has a first series connection point A'; The second arm switch group is formed by connecting two electronic switches 13' and 12' in series and has a second series connection point B'. Furthermore, the four electronic switches 11' to 14' of the motor driving circuit 1' are respectively selected from the transistor switches, and the four electronic switches 11' to 14' individually have a controlled end 111', 121. ', 131' and 141', each of the controlled ends 111'-141' can individually receive the forward rotation control signal or the reverse rotation control signal to control the electronic switches 11'-14' to be turned on or off. In addition, the controlled ends 111' and 131' of the electronic switches 11' and 13' of the bridge on the motor drive circuit 1' are separately connected to a transistor switch M1' and M2' by the transistor switch M1'. And the operation of M2' to control the action of the electronic switches 11' and 13' of the bridge on the motor drive circuit 1'.

Referring to FIGS. 2 and 5 again, the control output terminal group 21' of the control unit 2' cooperates with the phase number of the motor 3, and four control output terminals 211', 212', 213' and 214' are provided. The four control outputs 211'-214' are individually connected to the four electronic switches 11'~14', and the control unit 2' can generate the forward rotation control signal or the reverse rotation control signal, and control the forward rotation The signal or reverse rotation control signal is fed into the four electronic switches 11'~14' through the four control outputs 211'-214' to perform the on or off control of the four electronic switches 11'~14'.

Referring to FIGS. 2 and 5 again, the single-phase motor 3 disclosed in the present invention has a single coil 34 having an output end 341 and an input end 342. The input end 342 of the coil 34 is connected to the first series connection point A' of the first arm switch group, and the output end 341 of the coil 34 is connected to the second series connection point B' of the second arm switch group.

Furthermore, the single-phase motor 3 disclosed in the present invention can be controlled by the timings T1 and T2 as shown in FIG. In the operation of the sequence T1, the control unit 2' controls the two electronic switches 11' and 12' to be turned on, and the other two electronic switches 13' and 14' are turned off, so that the current is input from the input of the coil 34. 342 flows in and is defined as a positive current, and accordingly, the current waveform of the coil 34 as shown in the sequence T1 in Fig. 6 can be obtained.

Similarly, in the operation of the timing T2, the control unit 2' controls only the two electronic switches 13' and 14' to be turned on, so that current flows from the output terminal 341 of the coil 34, and is defined as a negative current. This corresponds to obtaining the current waveform of the coil 34 as shown in the sequence T2 in Fig. 6.

Therefore, in the normal power supply of the present invention, the control unit 2' can sequentially plan the forward rotation control signal by the timings T1 and T2, thereby controlling the motor 3 to rotate in the predetermined direction. In the case of abnormal power supply, the control unit 2' can also plan the reverse rotation control signal in reverse order according to the above-mentioned timing, that is, if the power supply interruption occurs at the timing T1, the sequential timing T2 and the timing T1 are sequentially performed. The operation, in turn, controls the rotation direction of the motor 3 at a time opposite to the predetermined direction to control the fan system motor 3 to stop immediately.

In addition, the motor having the two-phase system can also be modified by the circuit structure of the motor driving circuit 1, 1' and the control unit 2, 2' of the present invention, and the motor is driven by the forward rotation control signal and the reverse rotation control signal. The forward and reverse control can further achieve the effect that the fan system controls the instantaneous stop of the motor 3 under abnormal power supply conditions.

In summary, the control unit 2 and 2' of the present invention controls the rotation direction of the motor 3 to rotate in a direction opposite to the predetermined direction when the input voltage VCC is abnormally supplied, so as to perform the operation of stopping the motor immediately. Compared with the conventional fan system and its braking circuit, the present invention eliminates the need to provide the conventional instant stopping unit 94, thereby having the effect of reducing circuit cost and circuit connection complexity.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

[this invention]

1. . . Motor drive circuit

11. . . Electronic switch

111. . . Controlled end

12. . . Electronic switch

121. . . Controlled end

13. . . Electronic switch

131. . . Controlled end

14. . . Electronic switch

141. . . Controlled end

15. . . Electronic switch

151. . . Controlled end

16. . . Electronic switch

161. . . Controlled end

1'. . . Motor drive circuit

11’. . . Electronic switch

111’. . . Controlled end

12’. . . Electronic switch

121’. . . Controlled end

13’. . . Electronic switch

131’. . . Controlled end

14’. . . Electronic switch

141’. . . Controlled end

2. . . control unit

twenty one. . . Control output group

211. . . Control output

212. . . Control output

213. . . Control output

214. . . Control output

215. . . Control output

216. . . Control output

2'. . . control unit

211’. . . Control output

212’. . . Control output

213’. . . Control output

214’. . . Control output

3. . . motor

31. . . First coil

311. . . First output

312. . . First input

32. . . Second coil

321. . . Second output

322. . . Second input

33. . . Third coil

331. . . Third output

332. . . Third input

34. . . Coil

341. . . Output

342. . . Input

4. . . Energy storage unit

5. . . Voltage conversion unit

A. . . First tandem connection point

A’. . . First tandem connection point

B. . . Second tandem connection point

B’. . . Second tandem connection point

C. . . Third series connection point

M1. . . Transistor switch

M2. . . Transistor switch

M1’. . . Transistor switch

M2’. . . Transistor switch

M3. . . Transistor switch

[知知]

91. . . Bridge driver

92. . . control unit

93. . . Storage capacitor

94. . . Immediate stop circuit

95. . . Motor coil

M91. . . Electronic switch

M92. . . Electronic switch

M93. . . Electronic switch

M94. . . Electronic switch

M95. . . Electronic switch

M96. . . Electronic switch

M97. . . Electronic switch

M98. . . Electronic switch

Figure 1: Schematic diagram of the circuit connection of the conventional fan system and its brake circuit.

Figure 2 is a circuit diagram of a fan system and its braking circuit in accordance with a preferred embodiment of the present invention.

Fig. 3 is a circuit diagram showing a fan system and a brake circuit thereof according to a preferred embodiment of the present invention applied to a three-phase motor system.

Figure 4: Schematic diagram of the coil current timing of the motor in Figure 3.

Fig. 5 is a circuit diagram showing a fan system and a brake circuit thereof according to a preferred embodiment of the present invention applied to a single-phase motor system.

Figure 6: Schematic diagram of the coil current timing of the motor in Figure 5.

1. . . Motor drive circuit

2. . . control unit

twenty one. . . Control output group

twenty two. . . Voltage detection terminal

3. . . motor

4. . . Energy storage unit

5. . . Voltage conversion unit

Claims (14)

A fan system includes: a motor; a motor driving circuit electrically connected to the motor; and a control unit electrically connected to the motor driving circuit; wherein when an input voltage is supplied to the fan system, the control unit generates a forward rotation control signal for controlling the motor to rotate in a predetermined direction; when the input voltage interrupts power supply to the fan system, the control unit generates a reverse rotation control signal for controlling the motor to rotate in a direction opposite to the predetermined direction; The forward rotation control signal generated by the control unit is a periodic signal, and the periodic signal includes a plurality of timings, and the forward rotation control signals are arranged according to the plurality of timing sequences, and the timings of the periodic signals are reversed The sequence arrangement constitutes the reverse rotation control signal. The fan system of claim 1, wherein a voltage conversion unit is further disposed, and the voltage detecting end of the control unit is electrically connected to the anode of one of the diodes through the voltage conversion unit, and receives the Input voltage. The fan system of claim 1, wherein an energy storage unit is further disposed, the energy storage unit, the motor drive circuit and the control unit are electrically connected to one cathode of one of the diodes. The fan system of claim 2, wherein an energy storage unit is further disposed, the energy storage unit, the motor drive circuit and the control unit are electrically connected to one of the diodes of the diode. The fan system of claim 1, wherein the motor drive circuit is composed of a plurality of electronic switches, and the motor drive circuit is electrically connected to the motor to form a full bridge drive circuit or a half bridge drive. Circuit. The fan system of claim 2, wherein the voltage conversion unit is a voltage division network. The fan system of claim 1, wherein the control unit is a microcontroller or a motor drive IC. A braking circuit for a fan system includes a control unit that generates a forward rotation control signal to control a motor to rotate in a predetermined direction when an input voltage is supplied to the fan system; when the input voltage is interrupted to supply power to In the fan system, the control unit generates a reverse rotation control signal to control the motor to rotate in a direction opposite to the predetermined direction; wherein the forward rotation control signal generated by the control unit is a periodic signal, and the periodic signal includes a plurality of timings And constituting the forward rotation control signal according to the plurality of timing sequences, and the plurality of timings of the periodic signal are arranged in reverse order to constitute the reverse rotation control signal. The brake circuit of the fan system according to claim 8 is further provided with a voltage conversion unit, and a voltage detecting end of the control unit is electrically connected to an anode of a diode through the voltage conversion unit. And receiving the input voltage. The brake circuit of the fan system according to claim 8 is further provided with an energy storage unit, and the energy storage unit and the control unit are electrically connected to one cathode of one of the diodes. The brake circuit of the fan system according to claim 9 is further provided with an energy storage unit, and the energy storage unit and the control unit are electrically connected to one of the cathodes of the diode. The brake circuit of the fan system according to claim 8 is further provided with a motor drive circuit, wherein the motor drive circuit is composed of a plurality of electronic switches, and the motor drive circuit is electrically connected to the motor to form a motor. Full bridge drive circuit or half bridge drive circuit. The brake circuit of the fan system according to claim 9, wherein the voltage conversion unit is a voltage division network. The brake circuit of the fan system according to claim 8, wherein the control unit is a microcontroller or a motor drive IC.