TW202008707A - Driver integrated circuit for stepless speed change of alternating-current fan motor which has smaller circuit area and lower manufacturing cost - Google Patents

Abstract

A driver integrated circuit comprises a sensing unit, a control unit, a pulse width modulation unit, a boosting unit and a driving unit. The sensing unit senses an alternating-current motor and generates a sensing output indicating the current speed of the alternating-current motor. The control unit comprises a lookup table containing a plurality of speed difference values and a plurality of control signals respectively corresponding to the speed difference values. The control unit generates a speed control signal related to the target speed based upon an input signal indicating the target speed, the sensing output and the lookup table. The pulse width modulation unit generates a modulation signal based upon the speed control signal. The boosting unit boosts the modulation signal to generate a boost signal. The driving unit generates a driving signal related to the target speed according to the boost signal and outputs the driving signal to the alternating-current motor.

Description

Driving integrated circuit for stepless speed change of AC motor

The invention relates to a driving integrated circuit, in particular to a driving integrated circuit for driving a stepless speed change of an AC motor.

The prior art mainly uses a conventional variable frequency drive device to receive a power signal from a power source, and uses a variable frequency drive technology to control the speed of an AC motor. In detail, the conventional variable frequency drive device includes a control unit, a drive unit and other related units. The control unit is used to generate a control signal according to an external speed command, which indicates a target speed. The drive unit is electrically connected between the power supply and the control unit, and generates a drive signal with adjusted frequency and voltage according to the control signal and the power supply signal, the drive signal being related to the target speed. The conventional variable frequency drive device outputs the drive signal to the AC motor, so that the AC motor rotates according to the drive signal and drives a fan to rotate at the target speed, so that the fan generates the desired air volume.

However, in the conventional variable frequency drive device, the control unit and the drive unit are designed in two separate integrated circuits, resulting in a larger circuit area and higher manufacturing cost of the conventional variable frequency drive device. Therefore, there is still room for improvement in conventional variable frequency drive devices.

Therefore, the object of the present invention is to provide a driving integrated circuit that can overcome the disadvantages of the prior art.

Therefore, the driving integrated circuit of the present invention is suitable for receiving a power signal from a power source and generating a drive signal accordingly to drive an AC motor with stepless speed change. The driving integrated circuit includes a sensing unit, a control unit, a pulse width modulation unit, a boosting unit, and a driving unit.

The sensing unit senses the AC motor and generates a sensing output that indicates the current speed of the AC motor and a rotor position of the AC motor.

The control unit receives an input signal indicating a target speed, and is electrically connected to the sensing unit to receive the sensing output. The control unit includes a storage module storing a look-up table, the look-up table containing a plurality of speed differences And a plurality of control signals respectively corresponding to the speed differences, the control unit generates a speed control signal related to the target speed according to the input signal, the sensing output and the look-up table, the speed control signals are the One of the control signals.

The pulse width modulation unit is electrically connected to the control unit to receive the speed control signal, and generates a modulation signal whose voltage is adjusted according to the speed control signal, and the pulse width of the modulation signal varies with the speed control signal Change and change.

The boosting unit is electrically connected to the pulse width modulation unit to receive the modulation signal and boost the modulation signal to generate a boosting signal.

The driving unit is electrically connected between the boosting unit and the AC motor, and receives the boosting signal from the boosting unit, generates the driving signal related to the target rotational speed according to the boosting signal, and drives the The signal is output to the AC motor, and the drive unit is a unit with high voltage resistance.

The effect of the present invention is that the sensing unit, the control unit, the pulse width modulation unit, the boosting unit, and the driving unit are integrated into a single driving integrated circuit, so that the driving product of this embodiment Body circuits have a smaller circuit area and require lower manufacturing costs.

Referring to FIG. 1, the driving integrated circuit 20 of the present invention is suitable for being electrically connected between a power supply 11 and an AC motor 12 including a rotor 121, receiving a power supply signal VCC from the power supply 11 and generating a drive signal Ds accordingly The AC motor 12 is driven to be continuously variable. The driving integrated circuit 20 includes a sensing unit 2, a control unit 3, a pulse width modulation unit 4, a boosting unit 5, and a driving unit 6.

The sensing unit 2 continuously (or periodically) senses the signal generated by the SN polarity conversion of the AC motor 12 and the rotor 121 to generate a sensing output Ss, the sensing output Ss indicates that the AC motor 12 is currently The rotation speed and a rotor position of the rotor 121 of the AC motor 12. In this embodiment, the sensing unit 2 is a Hall sensing unit.

The control unit 3 receives an input signal Is indicating a target speed, and is electrically connected to the sensing unit 2 to receive the sensing output Ss. The control unit 3 includes a storage module 31 storing a look-up table 311, the look-up table 311 contains a plurality of speed difference values and a plurality of control signals corresponding to the speed difference values, respectively. The control unit 3 generates a speed control signal Cs related to the target speed according to the input signal Is, the sensing output Ss and the lookup table 311, and the speed control signal Cs is one of the control signals. In detail, the control unit 3 first subtracts the current speed of the AC motor 12 indicated by the sensing output Ss from the target speed indicated by the input signal Is to obtain a current speed difference, and then according to the current The speed difference is compared with the lookup table 311, and a control signal corresponding to the speed difference corresponding to the current speed difference is used as the speed control signal Cs.

It should be noted that, in this embodiment, the control unit 3 is a programmable control unit. The input signal Is is generated by a user from a user input interface (not shown) in response to a pair of input operations corresponding to the target speed, that is to say, the user can arbitrarily adjust the target speed according to the The driving integrated circuit 20 that generates the driving signal Ds based on the input signal Is can drive the AC motor 12 to achieve a stepless speed change. The rotation speed differences and the control signals contained in the look-up table 311 are pre-created by the user through a program setting, and the user can continuously update the look-up table 311. The rotation speed control signal Cs is used to cause the AC motor 12 to increase the rotation speed, decrease the rotation speed, or maintain the rotation speed. For example, when the current speed difference is negative (or positive), it means that the current speed of the AC motor 12 is greater than (or less than) the target speed, and the control unit 3 selects from the look-up table 311 according to the current speed difference The obtained rotation speed control signal Cs is used to reduce the rotation speed (or increase the rotation speed) of the AC motor 12. When the current speed difference is zero, it means that the current speed of the AC motor 12 is equal to the target speed. The speed control signal Cs generated by the control unit 3 is used to maintain the speed of the AC motor 12.

The pulse width modulation unit 4 is electrically connected to the control unit 3 to receive the speed control signal Cs, and according to the speed control signal Cs, generates a modulation signal Ms whose voltage is adjusted (the voltage of the modulation signal Ms is 12V ), and the pulse width of the modulation signal Ms changes with the change of the rotation speed control signal Cs. For example, when the current speed difference is negative and the speed control signal Cs is used to reduce the speed of the AC motor 12, the pulse width of the modulation signal Ms becomes narrower as the speed control signal Cs changes. Conversely, when the current speed difference is positive and the speed control signal Cs is used to increase the speed of the AC motor 12, the pulse width of the modulation signal Ms becomes wider as the speed control signal Cs changes.

The boosting unit 5 is electrically connected to the pulse width modulation unit 4 to receive the modulation signal Ms and boost the modulation signal Ms to generate a boosting signal Bs (the voltage level of the boosting signal Bs is 24V~48V), so that the voltage of the boost signal Bs is sufficient to drive the driving unit 6.

The driving unit 6 is electrically connected between the boosting unit 5 and the AC motor 12, and receives the boosting signal Bs from the boosting unit 5, and generates the drive related to the target speed according to the boosting signal Bs Signal Ds, and the driving signal Ds is output to the AC motor 12, so that the AC motor 12 rotates according to the driving signal Ds and drives a fan (not shown) to rotate at the target speed, so that the fan produces the desired Air volume. In this embodiment, the drive unit 6 is a unit with high voltage resistance. The voltage of the driving signal Ds is 110V or 220V, and the frequency is 50Hz or 60Hz. The driving unit 6 can drive a high-power AC motor with a required power of 20W~90W to rotate.

Further referring to FIG. 2, the driving unit 6 includes a signal switch 61, first and second capacitors 62, 63, a diode 64, first and second resistors 65, 66, and first and second electrical Crystal 67, 68.

The signal switch 61 has first to eighth pins P1 to P8. The first pin P1 receives the power signal VCC. The second and third pins P2 and P3 are electrically connected to the boosting unit 5 and are in phase. In cooperation with receiving the boost signal Bs, the fourth pin P4 is electrically connected to ground.

The first capacitor 62 is electrically connected between the first and fourth pins P1 and P4. The second capacitor 63 is electrically connected between the sixth and eighth pins P6 and P8. The diode 64 has an anode electrically connected to the first pin P1, and a cathode electrically connected to the eighth pin P8. The first resistor 65 has a first terminal electrically connected to the seventh pin P7, and a second terminal. The second resistor 66 has a first terminal electrically connected to the fifth pin P5, and a second terminal. The first transistor 67 has a first terminal receiving a bias voltage VDD, a second terminal electrically connected to the sixth pin P6, and a control terminal electrically connected to the second terminal of the first resistor 65 . The second transistor 68 has a first terminal, a second terminal electrically connected to ground, and a control terminal electrically connected to the second terminal of the second resistor 66. The outputs of the first terminal of the second transistor 68 and the second terminal of the first transistor 67 serve as the driving signal Ds.

It should be noted that, in this embodiment, the first capacitor 62 is a polar capacitor, and the first and second resistors 65 and 66 are each a current limiting resistor. The first and second transistors 67 and 68 are each an N-type metal oxide half-field effect transistor, wherein the drain, source and gate of the N-type metal oxide half-field effect transistor are the first and The first end, the second end, and the control end of each of the second transistors 67, 68. In addition, the role of the signal switcher 61 is to switch the boost signal Bs it receives through its own internal switch to stagger the clock of the boost signal Bs to divide into an output from the seventh pin P7 Signal to drive the first transistor 67, and another signal is output from the fifth pin P5 to drive the second transistor 68. In addition, the signal switch 61 continuously detects whether the first transistor 67 is normally output or locked through the sixth pin P6. If the first transistor 67 is locked, the signal switch 61 will The reset signal is output to the eighth pin P8 through the sixth pin P6 and the second capacitor 63 for resetting. The detailed circuit structure of the signal switch 61 has many different implementations and is well known to those having ordinary knowledge in the art, so it will not be repeated here.

In summary, since the sensing unit 2, the control unit 3, the pulse width modulation unit 4, the boosting unit 5, and the driving unit 6 are integrated into a single driving integrated circuit 20, In this way, the driving integrated circuit 20 has a smaller circuit area and a lower manufacturing cost than the conventional variable frequency drive device. In addition, since the sensing unit 2 continuously senses the sensing output Ss obtained by the AC motor 12 to know the current rotation speed of the AC motor 12 and the rotor position of the rotor 121, the driving integrated circuit 20 according to the The driving signal Ds generated by the sensing output Ss can enable the transistor (not shown) in the AC motor 12 to reach zero-point switching, so that the AC motor 12 does not generate a reverse electromotive force to the driving unit 6, which can be avoided The driving unit 6 is damaged due to the reverse electromotive force, so that the service life of the driving integrated circuit 20 of this embodiment can be extended. Furthermore, the sensing unit 2 is continuously sensing the AC motor 12 so that the driving integrated circuit 20 can automatically adjust the driving signal Ds automatically according to the sensing output Ss continuously output by the sensing unit 2, In this way, the driving integrated circuit 20 can achieve real speed detection and speed control of the AC motor 12 and avoid the situation that the speed of the AC motor 12 does not reach the target speed due to the quality difference or aging of the AC motor 12 itself.

However, the above are only examples of the present invention, and should not be used to limit the scope of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still classified as This invention covers the patent.

11‧‧‧Power supply 12‧‧‧AC motor 121‧‧‧Rotor 2‧‧‧Sense unit 20‧‧‧Drive integrated circuit 3‧‧‧Control unit 31‧‧‧Storage module 311‧‧‧Look-up table 4‧‧‧Pulse width modulation unit 5‧‧‧Boost unit 6‧‧‧Drive unit 61‧‧‧ Signal switch 62, 63‧‧‧ First and second capacitors 64‧‧‧ Diode 65, 66‧‧‧ First and second resistors 67, 68‧‧‧ First and second transistors Bs‧‧‧ Boost signal Cs‧‧‧Speed control signal Ds‧‧‧‧Drive signal Is‧‧‧ input signal Ms‧‧‧ Modulation signal P1~P8‧‧‧ First to eighth pins Ss‧‧‧Sense output VCC‧‧‧Power supply signal VDD‧‧‧ Bias voltage

Other features and functions of the present invention will be clearly presented in the embodiments with reference to the drawings, in which: FIG. 1 is a block diagram illustrating an embodiment of the present invention driving an integrated circuit; and FIG. 2 is a circuit block The figure illustrates a drive unit of this embodiment.

11‧‧‧Power

12‧‧‧AC motor

121‧‧‧Rotor

2‧‧‧sensing unit

20‧‧‧Drive integrated circuit

3‧‧‧Control unit

31‧‧‧Storage module

311‧‧‧Look-up table

4‧‧‧Pulse width modulation unit

5‧‧‧Boost unit

6‧‧‧Drive unit

Bs‧‧‧boost signal

Cs‧‧‧Speed control signal

Ds‧‧‧Drive signal

Is‧‧‧Input signal

Ms‧‧‧modulation signal

Ss‧‧‧sensing output

VCC‧‧‧Power signal

Claims (6)

A driving integrated circuit is suitable for receiving a power signal from a power supply and generating a driving signal to drive an AC motor stepless speed change. The driving integrated circuit includes: a sensing unit to sense the AC motor to Generate a sensing output that indicates the current speed of the AC motor and a rotor position of the AC motor; a control unit that receives an input signal indicating a target speed and is electrically connected to the sensing unit to receive the sense Measurement output, the control unit includes a storage module storing a look-up table, the look-up table contains a plurality of speed difference values and a plurality of control signals corresponding to the speed difference values respectively, the control unit according to the input signal, the sense The measured output and the look-up table generate a speed control signal related to the target speed, the speed control signal is one of the control signals; a pulse width modulation unit electrically connected to the control unit to receive the speed control Signal and generate a modulation signal whose voltage is adjusted according to the speed control signal, and the pulse width of the modulation signal changes with the change of the speed control signal; a boosting unit electrically connected to the pulse width modulation The unit receives the modulated signal and boosts the modulated signal to generate a boosted signal; and a driving unit electrically connected between the boosted unit and the AC motor and receives the boosted unit The boosting signal, and generating the driving signal related to the target rotation speed according to the boosting signal, and outputting the driving signal to the AC motor, the driving unit is a unit with high voltage specifications. The driving integrated circuit according to claim 1, wherein the sensing unit is a Hall sensing unit, and the sensing unit continuously senses the AC motor. The driving integrated circuit according to claim 1, wherein the control unit is a programmable control unit. The driving integrated circuit according to claim 1, wherein the control unit subtracts the target speed indicated by the input signal from the current speed of the AC motor indicated by the sensing output to obtain a current speed difference, And perform a lookup comparison from the look-up table according to the current speed difference, and a control signal corresponding to the speed difference corresponding to one of the speed differences and the current speed difference as the speed control signal. The driving integrated circuit according to claim 1, wherein the driving unit includes: a signal switch having first to eighth pins, the first pin receives the power signal, the second and third The pin is electrically connected to the boosting unit and cooperates to receive the boost signal, the fourth pin is electrically connected to ground; a first capacitor is electrically connected between the first and fourth pins; a diode , Having an anode electrically connected to the first pin, and a cathode electrically connected to the eighth pin; a second capacitor electrically connected between the sixth and eighth pins; a first resistor, Having a first end electrically connected to the seventh pin, and a second end; a second resistor, having a first end electrically connected to the fifth pin, and a second end; a first power The crystal has a first terminal receiving a bias voltage, a second terminal electrically connected to the sixth pin, and a control terminal electrically connected to the second terminal of the first resistor; and a second transistor , Having a first end, a second end electrically connected to ground, and a control end electrically connected to the second end of the second resistor, the first end of the second transistor and the first transistor The output of the second terminal serves as the driving signal. The driving integrated circuit according to claim 5, wherein the first capacitor is a polar capacitor, and the first and second resistors are each a current limiting resistor.

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